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17. Comparative study of the production of coumarins and furanocoumarins in three Ruteae species

Author

Bergheul, S., Limones-Méndez, M., Grosjean, J., Alain Hehn, Olry, A., Berkani, A., Université Abdelhamid Ibn Badis de Mostaganem, Laboratoire Agronomie et Environnement (LAE), and Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL)

Subjects
Furanocoumarins, A61K 36/75, Haplophyllum tuberculatum (Forsk) Juss, Coumarins, Ruta chalepensis L, Ruta angustifolia Pers, UHPLC-MS IPC Code, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Int cl (201501)-A61K 36/00
Abstract

International audience; Within specialized metabolites, coumarins and furanocoumarins represent a wide group of structurally diverse compounds and are specially produced in plants belonging to the Rutaceae family. Here we performed the furanocoumarin and coumarin-targeted chemical characterization of three Ruteae species collected from Algeria. Detection and quantification of 27 coumarins and furanocoumarins extracted from stems and leaves was carried out by UHPLC-MS. We highlighted significant chemical differences between these plants. Ruta chalepensis L. is the highest producer with 24.83 mmol/g dry material in stems and 15.70 mmol/g dry materials in leaves while Haplophyllum tuberculatum (Forsk.) is the lowest producer. We also showed a surprising chemical diversity between R. chalepensis L and R. angustifolia Pers. This chemical diversity might, therefore, be a helpful tool for phylogenetic identification of plants.

Published
2019

18. Development of a Dual-band Printed Antenna Based on a Nanocomposite Material made of Polyaniline charged by Iron-Nickel Nanopowder

Author

Hamouda, Z., Wojkiewicz, J.-L., Pud, A.A., Kone, Lamine, Bergheul, S., Lasri, T., Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Microtechnology and Instrumentation for Thermal and Electromagnetic Characterization - IEMN (MITEC - IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Dual-band antenna, [SPI]Engineering Sciences [physics], Nanocomposite, Flexible antenna, Polyaniline, Iron-Nickel nanopowder, Conductive materials
Abstract

International audience; One of the major challenges of printed electronics is to develop materials for flexible devices. Among these latter, antennas occupy a place of choice because of the new applications which are emerging. In this paper a flexible antenna based on a new nanocomposite, Polyaniline (PANI) charged by nanopowder of Iron-Nickel (Fe-Ni), operating in dual-band ([2.4-2.48] and [5.15-5.825] GHz) is proposed. This antenna, triangular/circular shaped with a coplanar waveguide (CPW) feeder to achieve wideband performance is printed on a 130μm thick Kapton® substrate. The nanocomposite fabricated (PANI/Fe-Ni), whose morphology was studied via scanning electron microscopy, has a conductivity of 9600 S/m. The performance of the antenna is analyzed through simulations and measurements which demonstrate a good agreement between each other. A maximum gain of 2.8 dBi for a 90μm thick nanocomposite is obtained. © 2019 European Association on Antennas and Propagation.

Published
2019

19. Design, Fabrication and Characterization of a new Wideband Antenna based on a Polyaniline/ Carbon coated Cobalt Composite

Author

HAMOUDA, Z., Wojkiewicz, J.-L., PUD, A. A., Kone, L., BERGHEUL, S., Lasri, T., Université Blida 2Faculté des sciences sociales, département de psychologie, Algérie, Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Lille Douai), Institut Mines-Télécom [Paris] (IMT), Institut de Recherche Interdisciplinaire [Villeneuve d'Ascq] (IRI), and Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Droit et Santé-Université de Lille, Sciences et Technologies

Subjects
[INFO]Computer Science [cs], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

20. Broadband dielectric characterization of flexible substrates using organic conductive polymer microstrip lines.

Author

Hamouda, Z., Wojkiewicz, J. L, Pud, A. A., Bergheul, S., and Lasri, T.

Subjects
MICROSTRIP transmission lines, CONDUCTING polymers, FLEXIBLE electronics, ORGANIC electronics, PRINTED electronics, POLYANILINES
Abstract

The interest from both consumers and industry toward flexible and organic electronics has grown enormously due to the unique properties of the materials used (flexible, stretchable, reconfigurable, and not easily breakable). In radio frequency and electronic organic systems fabrication, one important feature is the substrate complex dielectric constant. Particularly, in the context of the development of printed organic electronics technology, one of the major challenges is the knowledge of the effect on substrates complex dielectric constant retrieval when using organic conductive materials instead of classical metals (gold, copper, etc). Indeed, the precision on the determination of this parameter depends also on the characteristics of the conductive material used for the characterization of the substrate. When looking to full polymer devices, it is important to evaluate the precision on the determination of the parameters of interest without using metallic structures for the tests. This paper presents the characterization of a substrate on which a conductive polymer, polyaniline (PANI) doped with multiwall carbon nanotubes (MWCNTs) is deposited. The characterization technique is based on the well‐known 2 microstrip lines method. The microstrip lines, fabricated from PANI/MWCNTs, are processed on a substrate made of Kapton, which is a good candidate for flexible electronics. The extraction of the complex dielectric constant is made on the frequency range (1‐8 GHz). [ABSTRACT FROM AUTHOR]

Published
2020
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24. Polyaniline-carbon nanotubes composites - Based patch antenna

Author

Hamouda, Z., Wojkiewicz, J.-L., Pud, A.A., Belaabed, B., Bergheul, S., Lasri, T., Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Microtechnology and Instrumentation for Thermal and Electromagnetic Characterization - IEMN (MITEC - IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Conductivity, [SPI]Engineering Sciences [physics], Carbon nano-tube (CNT), Polyaniline (PANI), Patch antenna, Composites
Abstract

International audience; This paper presents the simulation and realization of a patch antenna made of composites based on Polyaniline (PANI) and carbon nanotubes (CNT). The antenna is designed to work at the frequency of 4.5 GHz; the dielectric substrates used is Rogers RT/duroid 5870 which has a dielectric permittivity of 2.35 and a loss tangent of 0.0012. The conductive polymer used has a conductivity of 4500 s/m, the carbon nanotubes used are multiwall carbon nanotubes. Simulation results show an antenna gain of 5.3dBi for PANI thickness of 70 μm. © 2014 European Association on Antennas and Propagation.

Published
2014

25. Contribution à la réalisation d'antennes patch à partir de polyaniline chargée de nanotubes de carbone

Author

Hamouda, Z., Wojkiewicz, J.L., Pul, A.A., Belaabed, B., Bergheul, S., Lasri, Tuami, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Laboratoire des Sciences Aéronautiques, Université de Saâd Dahlab [Blida] (USDB ), École des Mines de Douai (Mines Douai EMD), Institut Mines-Télécom [Paris] (IMT), Institut of Bioorganic Chemistry and Petrochemistry of NASU, National Academy of Sciences of Ukraine (NASU), Ecole supérieure des techniques aéronautiques (ESTA), École Supérieure des Technologies et des Affaires (ESTA), and Université Saâd Dahlab Blida 1 (UB1)

Abstract

Cet article présente la simulation d'une antenne patch réalisée à partir de polymères conducteurs (polyaniline) chargés par des nanotubes de carbone (NTC). Ce type d'antennes possède des propriétés électriques et mécaniques intéressante pour une utilisation dans des applications à faible coût nécessitant des propriétés de flexibilité. Les antennes ont été conçues à partir de deux types de substrats : la première est un 'verre époxy' de type FR4 ayant une permittivité relative εr =4.4, le second est un RT/Duroid 5870 de permittivité relative εr=2.32 à la fréquence 4.5GHz. La géométrie choisie pour les patchs est rectangulaire. Deux antennes patch en cuivre font office de référence et le polymère conducteur utilisé (PANI/NTC) présente une conductivité de 4500 s/m. Nous montons que les paramètres de rayonnement des antennes patch dépendent très fortement de la forme géométrique du patch (PANI/NTC) et des caractéristiques des substrats utilisés.

Published
2014

41. Structural, Mechanical and Magnetic Properties of Mechanically Alloyed Fe40Co60 Powders

Author

Otmane, Fadhela, Bergheul, S., Zergoug, M., and Azzaz, M.

Abstract

In this work we report on the structural, mechanical and magnetic properties of mechanically alloyed Fe40Co60 powders. Alloying formation, grain size, lattice parameter and internal strain were investigated using X-Ray Diffraction (XRD) measurements. The morphological aspect of the nanostructured powders was analysed by means of the Scanning Electron Microscopy (SEM). Compacted pastilles with circular shape have been under Vickers test of micro Hardness and magnetic measurements of Hysterisis loops. Discussed results according to milling time show that after 60 h milling the grain refinement is about 15.59 nm with internal strain of around 0.5809 %. The micro hardness increases with the decrease of the grain size and the hysterisis loop at 60 h milling is enhanced in term of decreased coercivity.

Published
2011
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42. X-Ray Diffraction, Microstructure and Mössbauer Studies of Nanostructured Fe72Al28 Powder

Author

Hamlati, Zineb, Guittoum, A., Bergheul, S., Souami, N., Taibi, K., and Azzaz, M.

Abstract

Nanocrystalline Fe72Al28 alloy samples were prepared by the mechanical alloying process using planetary high-energy ball mill. The alloy formation and different physical properties were investigated as a function of milling time, t, (in the 0-24 h range) by means of the X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), energy dispersive X-ray (EDAX) and Mössbauer spectroscopy. The complete formation of bcc-FeAl solid solution is observed after 4 h of milling. The lattice parameter, a (nm), quickly increases within the first hours of milling and reaches a maximum value of 0.291 nm at 12 h of milling time; then a (nm) decreases to a value of 0.2885 nm for 24 h. The grain size decreases from 55 to 10 nm, while the strain increases from 0.18% to 0.88%. Grain morphologies at different formation stages were observed by SEM. The Mössbauer spectra show different behaviors with the increase of milling time. Indeed, after 4 h, the Mössbauer spectrum shows the presence of a singlet and sextet. The singlet indicates the presence of paramagnetic phase characteristic of A2 disordered structure and the sextet with a mean hyperfine field, , of 21 T is indicative of ordered DO3 structure. After 8 h of milling, the paramagnetic phase disappears leading to the appearance of a sextet, with a mean hyperfine field, Hhf, equal to 24.18 T which is characteristic of DO3’ structure. For the higher milling time i.e. 24 h, the Mössbauer spectrum was analyzed with two components. The first one with equal to 29.9 T is still indicative of ordered DO3, however, the second with a value of 10.25 T is characteristic of the fine domain B2 ordered structure.

Published
2011
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43. How Fe60Co40 and Fe72Al28 Nano-Alloys Produced by Mechanical Alloying Behave when Exposed to Microwaves

Author

Otmane, Fadhela, Bergheul, S., Hamlati, Z., and Azzaz, M.

Abstract

Fe60Co40 and Fe72Al28 nano-alloys were synthesized from elemental powders via highenergy mechanical alloying. The prepared samples were characterized using X-ray diffraction, scanning electron microscopy and X-band waveguide to measure the reflection loss in a frequency range of 9-10 GHz. The XRD patterns show that disordered Fe60Co40 solid solution with a bodycentred cubic structure is formed for milling times longer than 12 h, and after 4h milling, the solid solution Fe72Al28 has been largely formed. Morphological studies indicate an average grain size of 10 to 15 nm. The microwave- absorbing characteristic reveal good performance for Fe60Co40 compared to Fe72Al28, the maximum reflection loss is about -12 dB for the absorber.

Published
2008
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44. Facteurs prédictifs de l’anxiété des étudiants durant la pandémie (COVID-19)

Author

Bergheul, S., Carole, C., Augustin, E., Oscar, L., and Bedoya Mejía, J.P.

Abstract

La pandémie de la maladie à coronavirus (COVID-19) a provoqué une crise sanitaire majeure et une mise en quarantaine de la majorité de la population planétaire. En période de confinement, des symptômes anxieux peuvent apparaître. La pandémie modifie considérablement la vie des individus en devenant une manifestation concrète de la menace. L’exposition constante à des informations concernant le virus peut faire augmenter l’anxiété, d’autant plus que ces informations peuvent être erronées ou contradictoires. Cet article porte sur les facteurs qui prédisent l’anxiété des étudiants en contexte de pandémie.

Published
2021
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45. CPW-fed dual band monopole antenna based on conductive polymers

Author

Hamouda, Z., Wojkiewicz, J. -L, Alexander Pud, Kone, L., Belaabed, B., Bergheul, S., Lasri, T., Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Microtechnology and Instrumentation for Thermal and Electromagnetic Characterization - IEMN (MITEC - IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
monopole antenna, [SPI]Engineering Sciences [physics], multiwall carbon nanotubes, flexible antenna, conductive polymer, polyimide, coplanar waveguide fed (CPW-fed), polyaniline
Abstract

International audience; This paper describes the design, fabrication and characterization of a flexible CPW-fed monopole organic antenna, based on a multiwall carbon nanotubes (MWCNT) doped Polyaniline (PANI). The antenna is printed on a 130μm Kapton® substrate. The design proposed allows the coverage of two frequency bands, 1.8 to 2.8 GHz and 4.5 to 7 GHz, which include ISM frequencies (2.45 GHz and 5.8 GHz). The dual-band monopole antenna is made of a 65μm-thick conducting polymer (PANI/MWCNT) whose measured conductivity is 5500 S/m. The measurement results of the PANI/MWCNT monopole antenna show a good agreement with the simulation data. Moreover, it achieves a maximum gain of 0.40 dBi at 2.4 GHz and 2.4 dBi at 5.8 GHz. Altogether; the results confirm the potential of conductive polymers for the realization of flexible antennas. © 2015 EurAAP.

48. Formation and Magnetic Properties of Nanocrystalline Fe60Co40 Alloys Produced by Mechanical Alloying.

Author

Bergheul, S., Tafat, H., and Azzaz, M.

Subjects
IRON alloys, MECHANICAL alloying, BALL mills, MAGNETIC properties, SCANNING electron microscopy, MICROMECHANICS, PHASE equilibrium
Abstract

The Fe60Co40 alloys were prepared by mechanical alloying of the Fe and Co powders using a high-energy ball mill. They were studied with respect to phase formation and magnetic properties using x-ray diffraction, scanning electron microscopy, and measurements of coercivity and remanence (Br). The evaluation of Fe lattice parameters during milling showed that formation of a body-centered cubic solid solution occurred by mechanical alloying after 12 h of milling. Intensive milling of Fe-Co powders results in a nonequilibrium microstructure characterized by grain refinement to a minimum of 10-13 nm and the introduction of internal strain up to 0.5%. [ABSTRACT FROM AUTHOR]

Published
2006
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50. [Comparative study on the predictive factors of anxiety among Quebec university students during the pandemic (COVID-19)].

Author

Bergheul S, Labra O, Castro C, Ependa A, Bedoya J, and Marcotte-Beaumier G

Subjects
Humans, Quebec epidemiology, Universities, Anxiety epidemiology, Students, Depression, Pandemics, COVID-19 epidemiology
Abstract

Objective In this study, we present the results of a comparative research carried out on three cohorts of university students in the context of a pandemic. Several research indicate that the anxiety level of populations has increased significantly. Method In this article, we present the results of a comparative study of three cohorts study conducted on 1674 Quebec students. Participants were recruited at three separate time points, in the summer of 2020 (cohort 1; N = 398), in the fall of 2020 (cohort 2; N = 621) and in the winter of 2021 (cohort 3; N = 655). Anxiety was measured using Beck's anxiety inventory and several sociodemographic variables were tested. Results Results from cohort 1 indicate that being younger and having a mental health diagnosis may be vulnerability factors for anxiety. For cohort 2, the interaction of gender x diagnosis x program of study had a significant effect. Age and family income were predictive of significant anxiety in cohort 3. Limitations and perspectives of the study are explored. Conclusion The study recommends that the results be considered in developing preventive and intervention programs in the post-pandemic period.

Published
2023

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