Papers by Abdelkader Nadjem
Social media addiction in middle and high school students during the coronavirus disease 2019 (COVID-19) pandemic
معارف, Jun 30, 2021
Tribocharging of granular polymer as affected by the voltage waveform and frequency of a pretreatment by a dielectric barrier discharge
2019 International Conference on Advanced Electrical Engineering (ICAEE), Nov 1, 2019
Triboelectric charges created by friction or contact of several kind of materials are commonly re... more Triboelectric charges created by friction or contact of several kind of materials are commonly referred to as a source of troubles in most industrial applications, requiring their elimination in most cases. In contrast, the tribocharging of insulating materials is a crucial step for many electrostatic applications involving the electric charges to their proper functioning. Therefore, the acquired charges in this case should be as high as possible to attain the best process performances. The triboelectric charging level depends strongly on the surface state. In this context, the Dielectric Barrier Discharge (DBD), which is non-thermal energetic plasma, is known for its capability to modify surface properties of treated materials and consequently can affect their triboelectric behavior. The purpose of the present work is to study the effect of the DBD electrical parameters on the discharge characteristics and, therefore, the subsequent triboelectric behavior of treated particles of PVC. The carried experiences include the influence of the signal waveform, the applied voltage amplitude and the frequency on the DBD discharge characteristics and the resulting triboelectric charge of PVC particles submitted to the discharge. The DBDtreated particles were charged by triboelectricity in a vibratory device for 5 min. The triboelectric charge acquired by the untreated and DBD-treated particles was measured using a Faraday pail connected to an electrostatic electrometer. The obtained results show that the variation of triboelectric charge acquired by DBD-treated particles depends strongly on the discharge current as well as the discharge distribution in the air gap. The triboelectric charge has been optimally enhanced by about 25% when the square waveform is used with an applied voltage of 27 kV and a 400 Hz frequency.
Experimental Study of an Inclined-Plane Electrostatic Separator
Springer eBooks, 2018
Free-fall electrostatic separator is the most basic and a standard solution to separate insulator... more Free-fall electrostatic separator is the most basic and a standard solution to separate insulators mixtures. In this paper, an inclined configuration based on free-fall separator was studied. The performances of the studied separator were evaluated through recovery and purity of a separated mixture composed of Polyamide (PA) and Polycarbonate (PC) granular materials. Mainly, the applied voltage to the electrodes and the angle of inclination were the two studied factors. These two factors were varied respectively between 5 kV and 10 kV for the voltage and 25° to 90° for the inclination angle. The obtained results show that recovery rate is increased as the voltage increase so that the more is the voltage the more is the recovered quantity. Conversely, the best results are obtained for lowest inclination angle (25°). At 10 kV and 25°, the recovery rate was more than 70% with products purity roughly 97% for the PA and 98% for the PC. The inclined-plane allowed the increase in recovery rate and purity in comparison to the standard free-fall configuration.
Electrostatic characterization of cereal grains
The aim of the present study is to characterize the electrical and electrostatic properties of th... more The aim of the present study is to characterize the electrical and electrostatic properties of the four kinds of cereal grains namely barley, durum wheat, soft wheat and impurities. The samples were charged by exposing them to a negative corona discharge generated by a needle electrode, facing a grounded plate electrode. Surface potential decay and electric charge measurements were recorded in order to determinate the electrostatic behavior of the above mentioned cereals. The obtained results show that the considered cereals have almost identical electrostatic characteristics, while, the impurities are more resistant. The I-V curves have shown that barley is slightly different than durum and soft wheat, the last are very close.
Acta Chimica Slovenica
For carbon steel X70 in a 1 M hydrochloric acid solution, Scorzonera undulata acetate extract (SU... more For carbon steel X70 in a 1 M hydrochloric acid solution, Scorzonera undulata acetate extract (SUAc) was investigated as an ecological corrosion inhibitor. The anti-corrosion effect of Scorzonera undulata extract is studied using potentiodynamic polarization analysis and electrochemical impedance spectroscopy (EIS). The polarization curves clearly show that the extract is an excellent mixed inhibitor. Our findings show that the maximum inhibition efficiency of 83% has been found with inhibitor concentration up to 400 mg/L at 298 Kelvin. The Langmuir isotherm is followed by the inhibitor’s adsorption on the steel surface and physical adsorption was discovered to be the mechanism. To understand the inhibitory mechanism, thermodynamic parameters (ΔG°ads) and activation parameters (Ea, ΔHa, and ΔSa) were determined. Scanning electron microscopy (SEM) and X-ray photoelectron spectrometry studies of the surface chemistry and morphology are included to this investigation. The results obtai...
Semolina extraction from wheat bran using an electro‐separation process
Journal of Food Processing and Preservation
Tout d'abord louanges et remerciements à Dieu pour m'avoir donné le courage et la force de termin... more Tout d'abord louanges et remerciements à Dieu pour m'avoir donné le courage et la force de terminer ce modeste travail. Je tiens à remercier mon directeur de thèse, M. Miloud KACHI, pour ses multiples conseils, suggestions et pour toutes les heures qu'il a consacrées à établir cette recherche. J'aimerais également lui dire à quel point j'ai apprécié sa grande générosité, disponibilité et ses qualités d'écoute et de compréhension. Cela a été un grand privilège pour moi d'avoir coopérer avec Monsieur le Professeur Lucien DASCALESCU du laboratoire d'étude aérodynamique IUT d'Angoulême de l'université de Poitier. Je tiens à lui adresser mes chaleureux remerciements pour ses remarques et conseils pertinents. Mes remerciements s'adressent également à Messieurs Karim MEDLES et Thami ZEGHLOUL pour toute leur aide, leur précieux conseils et leurs encouragements continus qu'il m'a prodigué durant la réalisation de cette thèse et leur confiance à mon égard. Je suis reconnaissant à Messieurs: Marian-Bogdan NEAGOE et Gontran RICHARD, doctorants à l'IUT d'Angoulême, pour leurs aides précieuses à la réalisation des manips. J'adresse tous mes remerciements à Professeur Ahcene LEMZADMI pour avoir accepté de présider mon jury. Mes remerciements vont également à Messieurs : Lazhar HEROUS, Noureddine ZOUZOU et Mokdad REMADNIA qui m'ont fait l'honneur d'examiner, évaluer et juger cette thèse. Mes remerciements s'adressent aussi à tous les membres de l'Institut PPRIME, de l'IUT d'Angoulême, de l'Université de Sidi-Bel-Abbès et de l'Université de Guelma, qui ont été proches de moi ces trois dernières années.
Social media addiction in middle and high school students during the coronavirus disease 2019 (COVID-19) pandemic
Electrostatic characterization of cereal grains
2017 5th International Conference on Electrical Engineering - Boumerdes (ICEE-B), 2017
The aim of the present study is to characterize the electrical and electrostatic properties of th... more The aim of the present study is to characterize the electrical and electrostatic properties of the four kinds of cereal grains namely barley, durum wheat, soft wheat and impurities. The samples were charged by exposing them to a negative corona discharge generated by a needle electrode, facing a grounded plate electrode. Surface potential decay and electric charge measurements were recorded in order to determinate the electrostatic behavior of the above mentioned cereals. The obtained results show that the considered cereals have almost identical electrostatic characteristics, while, the impurities are more resistant. The I-V curves have shown that barley is slightly different than durum and soft wheat, the last are very close.
Experimental Study of an Inclined-Plane Electrostatic Separator
Free-fall electrostatic separator is the most basic and a standard solution to separate insulator... more Free-fall electrostatic separator is the most basic and a standard solution to separate insulators mixtures. In this paper, an inclined configuration based on free-fall separator was studied. The performances of the studied separator were evaluated through recovery and purity of a separated mixture composed of Polyamide (PA) and Polycarbonate (PC) granular materials. Mainly, the applied voltage to the electrodes and the angle of inclination were the two studied factors. These two factors were varied respectively between 5 kV and 10 kV for the voltage and 25° to 90° for the inclination angle. The obtained results show that recovery rate is increased as the voltage increase so that the more is the voltage the more is the recovered quantity. Conversely, the best results are obtained for lowest inclination angle (25°). At 10 kV and 25°, the recovery rate was more than 70% with products purity roughly 97% for the PA and 98% for the PC. The inclined-plane allowed the increase in recovery ...
Triboelectric charging is used for many applications including electrostatic separation of granul... more Triboelectric charging is used for many applications including electrostatic separation of granular insulating materials. For this application, the granules should get the highest electric charge, so that the electric field for ces could easily separate them. Triboelectric charging is a surface phenomenon and dielectric bar rier discharge (DBD) is known for its ability to change surface properties of different materials. This study is focused on the evaluation of the DBD factors that might enhance the triboelectric charging properties of Polypropylene (PP) mm-size granules: the discharge duratio n, as well as the frequency and the amplitude of the high-voltage. After having been exposed to the DBD, the granules were tribocharged in a vibratory device for 5 min. Then, the charge was measured by a Faraday pail connected to an electrostatic voltmeter. The result s show that under optimal operating conditions, DBD exposure can enhance the triboelectric c harging by about 30%.
Tribocharging of granular polymer as affected by the voltage waveform and frequency of a pretreatment by a dielectric barrier discharge
2019 International Conference on Advanced Electrical Engineering (ICAEE), 2019
Triboelectric charges created by friction or contact of several kind of materials are commonly re... more Triboelectric charges created by friction or contact of several kind of materials are commonly referred to as a source of troubles in most industrial applications, requiring their elimination in most cases. In contrast, the tribocharging of insulating materials is a crucial step for many electrostatic applications involving the electric charges to their proper functioning. Therefore, the acquired charges in this case should be as high as possible to attain the best process performances. The triboelectric charging level depends strongly on the surface state. In this context, the Dielectric Barrier Discharge (DBD), which is non-thermal energetic plasma, is known for its capability to modify surface properties of treated materials and consequently can affect their triboelectric behavior. The purpose of the present work is to study the effect of the DBD electrical parameters on the discharge characteristics and, therefore, the subsequent triboelectric behavior of treated particles of PVC. The carried experiences include the influence of the signal waveform, the applied voltage amplitude and the frequency on the DBD discharge characteristics and the resulting triboelectric charge of PVC particles submitted to the discharge. The DBDtreated particles were charged by triboelectricity in a vibratory device for 5 min. The triboelectric charge acquired by the untreated and DBD-treated particles was measured using a Faraday pail connected to an electrostatic electrometer. The obtained results show that the variation of triboelectric charge acquired by DBD-treated particles depends strongly on the discharge current as well as the discharge distribution in the air gap. The triboelectric charge has been optimally enhanced by about 25% when the square waveform is used with an applied voltage of 27 kV and a 400 Hz frequency.
Influence of the geometrical parameters of a dielectric barrier discharge reactor on the subsequent tribocharging of granular polymers
Journal of Electrostatics
Corona discharge as affected by the presence of various dielectric materials on the surface of a grounded electrode
IEEE Transactions on Dielectrics and Electrical Insulation
Triboelectrification of granular insulating materials as affected by dielectric barrier discharge (DBD) treatment
Journal of Electrostatics
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Papers by Abdelkader Nadjem