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Search Results: 1 - 10 of 1357 matches for " Dayane Habib "
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Crystal Growth, Structural and Optical Studies of CuGa3Se5 Bulk Compounds  [PDF]
Dayane Habib, Georges El Haj Moussa
World Journal of Condensed Matter Physics (WJCMP) , 2016, DOI: 10.4236/wjcmp.2016.61004
Abstract: Bulk materials were synthesized by the Bridgman technique using the elements Cu, Ga, Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity. Optical response (Photoconductivity) and Photoluminescence (PL) and PL-excitation (PLE) at temperatures from 4.2 to 77 K were also used to estimate the band-gap energy of Cu-Ga3Se5. They show a nearly perfect stoechiometry and present p-type conductivity. CuGa3Se5 either have an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained by Photoconductivity and Photoluminescence (PL) for the different samples is 1.85 eV. Studying the variation of the gap as a function of the temperature shows that the transition is a D-A type. The defects that appear are probably GaCu.
Spectroscopic Ellipsometry Study of the Dielectric Function of Cu(In1–xGax)3Se5 Bulk Compounds: Identification of Optical Transitions  [PDF]
Dayane Habib, Georges El Haj Moussa
World Journal of Condensed Matter Physics (WJCMP) , 2017, DOI: 10.4236/wjcmp.2017.74009
Abstract: Using Spectroscopic Ellipsometry (SE), the optical properties of Cu(In1xGax)3Se5 bulk compounds, grown by the Bridgman method, were analyzed by varying x composition (0 ≤ x ≤ 1). Energy levels above the gap in the band scheme were determined by measuring the complex dielectric function \"\"?at room-temperature for energies between 1.5 and 5.5 eV using a variable angle of incidence ellipsometer. The transitions values E1, E2 and E3 were observed above the gap for different samples of Cu(In1xGax)3Se5 alloy. When a gallium atom replaces an indium atom, one assumes globally that the levels related to selenium and copper are unchanged. Conversely, the levels corresponding to the conduction band are shifted towards higher energies. Thus, the gap increases as the composition of gallium increases. Spectroscopic Ellipsometry (SE) gave evidence for the interpretation of the choice of gap values which were compatible with that obtained from solar spectrum. Several other characterization methods like Energy Dispersive Spectrometry (EDS), hot point probe method, X-ray diffraction, Photoluminescence (PL), Optical response (Photoconductivity) were presented in this paper. The Cu(In1xGax)3Se5 have an Ordered Vacancy Chalcopyrite-type structure with lattice constants varying as a function of the x composition. The band gap energy of Cu(In1xGax)3Se5 compounds is found to vary from 1.23 eV to 1.85 eV as a function of x.
Identification of Optical Transitions by Spectroscopic Ellipsometry (SE) on CuIn3Se5 Bulk Compounds  [PDF]
Dayane Habib, Georges El Haj Moussa
World Journal of Condensed Matter Physics (WJCMP) , 2017, DOI: 10.4236/wjcmp.2017.74010
Abstract: Bulk materials were synthesized by the Bridgman technique using the elements Cu, In and Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity, Optical response (Photoconductivity) and Photoluminescence (PL) to determine the band gap value and Spectroscopic Ellipsometry to find energy levels above the gap in the band scheme at room-temperature. They show a nearly perfect stoechiometry and present a p-type conductivity. CuIn3Se5 either has a Stannite structure, an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained for the different samples was 1.23 eV. Energy levels above the gap in the band scheme were determinate by measuring the dielectric function at room temperature for energies lying between 1.5 and 5.5 eV. Many transitions were observed above the gap for different samples. Spectroscopic Ellipsometry gave evidence for the interpretation of the choice of gap values which were compatible with that obtained from solar spectrum.
Fabrication, Characterization and Optical Properties of CuIn3Se5 Bulk Compounds  [PDF]
Dayane Habib, Ouloum Aoudé, Slyman Karishy, Georges El Haj Moussa
World Journal of Condensed Matter Physics (WJCMP) , 2015, DOI: 10.4236/wjcmp.2015.53021
Abstract: The present work prepared the CuIn3Se5 ingots by using a horizontal Bridgman method and investigated the Energy Dispersive Spectrometry (EDS) and X-Ray Diffraction (XRD) to calculate the compositions of the ingots. Photoluminescence was used to check their optical properties. It was found that CuIn3Se5 had either a Stanite structure, an Ordered Defect Chalcopyrite (ODC) structure, or an Ordered Vacancy Chalcopyrite (OVC) structure. The gap energy obtained by Photoluminescence (PL) for the different samples is 1.23 eV. Studying the variation of the gap as a function of the temperature shows that the transition is a D-A type.
Influence of Iodine Pressure on the Growth of CuIn1-xGaxSe2 Thin Films Obtained by Close-Spaced Vapor Transport “CSVT”  [PDF]
Dayane Habib, Roy Al Asmar, Ziad El Helou, Georges El Haj Moussa
World Journal of Condensed Matter Physics (WJCMP) , 2013, DOI: 10.4236/wjcmp.2013.34026
Abstract:

We present the results concerning photovoltaic materials CuIn1-xGaxSe2 thin films, which were obtained by close-spaced vapor transport “CSVT”. The influence of the iodine pressure on the growth of CuIn1-xGaxSe2 thin films was studied. The thin films were characterized by Energy Dispersive Spectrometry (EDS), Scanning Electron Microscope (SEM), hot point probe method, X-Ray Diffraction (XRD), Photoluminescence, and Optical response (Photoconductivity). At high pressure, the deposition rate was very important. The films were relatively thick and homogeneous with large grains dimensions. These films are formed of crystals placed in a preferential orientation depending on the plan (112). At low pressure, the films were thin and inhomogeneous with relatively small grains. These films of crystals didn’t have preferential orientation.

Supply Chain Management (SCM): Its Future Implications  [PDF]
Mamun Habib
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.29040
Abstract:

This keynote paper represents theory of Supply Chain Management (SCM) and its future implications as well as demonstrates chronological prospective of SCM in terms of time frame in different areas of manufacturing and service industries. SCM has been widely researched in numerous application domains during the last decade. Despite the popularity of SCM research and applications, considerable confusion remains as to its meaning. There are several attempts made by researchers and practitioners to appropriately define SCM. Amidst fierce competition in all industries, SCM has gradually been embraced as a proven managerial approach to achieving sustainable profits and growth. Finally, this study demonstrates Educational Supply Chain Management, as the application of SCM in the service industry, which would unlock other applications of SCM in different arenas. Integrated Tertiary Educational Supply Chain Management (ITESCM) model would be verified through Structural Equation Modeling (SEM) Techniques that would describe in this paper. The ITESCM model furnishes stakeholders of the supply chain with appropriate strategies to review and appraise their performance toward fulfillment of ultimate goals, i.e. producing high-ca- liber graduates and high-impact research outcomes, which represent two main contributions, for the betterment of the society.

Synthesis and Polymerization of N,N'-[Bis(4,4'-Hydroxypropyl Methacrylate Phenylester) Pyromellitimide] Thermoset Polymer by Microwave Irradiation  [PDF]
Habib Saedi
Advances in Chemical Engineering and Science (ACES) , 2016, DOI: 10.4236/aces.2016.62019
Abstract: A new difunctional monomer N,N'-[bis(4,4'-hydroxypropyl methacrylate phenyl ester) pyromellitimide] (BHPMEPM), was synthesized by the reaction of the bis(4-carboxyphenyl)-N,N'-pyromelli- timide acid (diacid-diimide), and two molar equivalents of glycidylmethacrylate (GMA). The reaction was carried out by microwave radiation. The presence of difunctional groups, double bond groups, makes the monomer a potential material for obtaining thermosetting product. The curing and thermal stability of the crosslinked products were studied by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) techniques. The difunctional monomer and its thermoset polymer were characterized by FT-IR, 1H-FT-NMR and CHN elemental analysis.
Anodic Stripping Voltammetric Determination of Nitrite Using Carbon Paste Electrode Modified with Chitosan  [PDF]
Ibrahim H. I. Habib
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.22035
Abstract: A simple method for anodic stripping voltammetric determination of nitrite using carbon paste electrode modified with biomolecular chitosan, is described. In this method, the electrode is activated electrochemically by scanning 5 replicates over the potential range from +500 to +1400 mV immersing in 0.5 M HCl solution. Following this step, the nitrite sample containing 0.1 M KCl is preconcentrated on the activated electrode at +500 mV for 30 s. The deposited anions are then oxidized by different modes of sweep in the oxidation direction. Chemical and electrical parameters affecting the voltammetric measurements are optimized. The peak current is linear proportional to the NO2- concentration within the range 0.41 - 4.1 µg/ml, with detection limit 0.187 µg/m using differential pulse mode. The relative standard deviation is 0.285% for 2.46 µg/ml (five replicates). No interference is observed due to oxygen dissolved in the sample so that nitrogen purging is not needed in this case. The result obtained by the modified electrode is more accurate and selective than the unmodified electrode.
A Bio-Hydraulic Modelling Approach to Control the Hemodialysis Patient Status—Calculus and Validation  [PDF]
Mohamed Habib Sellami
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.33026
Abstract:

We have developed a model permitting the control of the hemodialysis patient status. We have represented the functioning of each body compartment by a set of differential equations that express the mass balance of the carbonate and bicarbonate concentrations in each one. Experimental data from bibliography were analyzed and compared to our calculus. Results were well satisfying.

Cartoons’ Effect in Changing Children Mental Response and Behavior  [PDF]
Khaled Habib, Tarek Soliman
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.39033
Abstract: Factors that sculpture children’s way of thinking are found mostly in the environment where they grow up. These include daily events, memorable experiences and peak feelings. Cartoons are one of the daily habits for our children; studies have proven that an average child with a facility of a TV and a satellite connection at his home watches approximately 18,000 hours of television from kindergarten to high school graduation. How does this experience affect our children minds? Does it have positive or negative effects? What types of contents are delivered to our kids in a cartoonish show? Are all shows trustable, or shall parents pay monitoring attention to the TV shows? How does our children brain absorb and analysis information in the first place? These questions and others will be answered through this survey-experimental research [1] [2].
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