Showing 6 results for Farid
Najwa Gouitaa, Lamcharfi Taj-Dine, Bouayad Lamfaddal, Abdi Farid, Mohamed Ounacer, Mohammed Sajieddine,
Volume 18, Issue 2 (June 2021)
Abstract
Farid Lekmine, Hachemi Ben Temam, Elhachmi Temam,
Volume 18, Issue 3 (September 2021)
Abstract
Nickel phosphorus alloy coatings were prepared by electrodeposition route from sulfate electrolyte bath at various current densities. SEM studies reveal spherical grains covered the entire surface with uniform distribution. EDX results showed a linear increase of P content in the developed deposits with current density and therefore, enhancing the grains size and drop of the hardness values. XRD studies reveal monocrystalline orthorhombic alloys at a low amount of phosphorus (10.88 wt. %). Corrosion tests show that 1 A.dm-2 is the best applied current density giving the nobler Ecorr (-171.4 mV) and the lower icorr (4.64 µA/cm2).
Najwa Gouitaa, Lamcharfi Taj-Dine, Abdi Farid , Ahjyaje Fatima Zahra,
Volume 18, Issue 3 (September 2021)
Abstract
In this study we have synthesis the Zr substituted BaTi0.80Fe0.20O3 ceramics at different content of Zr from x=0.00 to 0.10 by using the solid-state route. The room temperature X-ray diffraction results confirmed the coexistence of the two tetragonal and hexagonal phases for x ≤ 0.050 of Zr content. While above 0.050 the hexagonal phase disappears in benefit of tetragonal phase. The Raman results confirmed the formation of these phases obtained with XRD. The scanning electron micrographs consist of both spherical and straight grain forms for x=0.000 to 0.075, and only spherical grain form for x=0.100 attributed to the tetragonal phase. Also, the grain size increases accompanied with a decrease in density of ceramics with increasing Zr content up to 0.050 then decreases accompanied with an increase in density. Detailed studies of dielectric permittivity measurement have provided a presence of two anomalies Te and TR-O at different temperatures, with a relaxation phenomenon and diffuse behavior which is very important for ceramic at x=0.075 of Zr content. The dielectric permittivity values of the two anomalies of Zr substituted BaTi0.80Fe0.20O3 ceramics increase with increase of Zr content and the dielectric loss is minimal at x=0.100 of Zr content. The conductivity increases with the increasing of Zr substitution from 0.025 to 0.075 levels while for x = 0.100 the dielectric conductivity decreases. And the Cole-Cole analysis indicates a negative thermal resistivity coefficient (NTCR) behavior of these materials and an ideal Debye-type behavior.
Farideh Golbabaie, Somayeh Farhang Dehghan, Majid Habibi Mohraz, Elham Akhlaghi Pirposhteh,
Volume 18, Issue 4 (December 2021)
Abstract
The present study aims to investigate the role of the electrostatic mechanism in the filtration process of Polyacrylonitrile nanofibers containing single-walled carbon nanotube. The nanofibers were fabricated via electrospinning using 16wt% Polyacrylonitrile polymer (PAN) solution, single-wall carbon nanotubes (SWNT) at a ratio of 99:1 along with N and N-Dimethylformamide solvents. Initial filtration efficiency was tested as per ISO 29463:2011 standard inside a test rig. An electrostatic discharge test was performed via the chemical treatment of the filter media with Isopropyl alcohol in accordance to EN779 standard. Mean initial filtration efficiency of the nanofiber media in the capturing of 100nm and 200nm particles were 95.92% ±2.74 and 97.26% ±1.11 respectively, while for particles between 80nm to 250nm, this was 96.73% ±2.74. The efficiency of the untreated media was 0.2% to 1.2% higher than the PAN/SWNT media after electron discharge using Isopropyl alcohol with an even bigger difference being observed at lower particle size ranges. After treatment with Isopropyl alcohol, the pressure drop of the filtration media was increased from 164.7 Pa to 185.3 Pa. The reduction in filtration efficiency observed after the electrostatic discharge test indicates that the electrical charge of the electrospun nanofibers is influential in its initial efficiency for removing the submicron particles.
Ahabboud Malika, Najwa Gouitaa, Ahjyaje Fatimazahra, Lamcharfi Taj-Dine, Abdi Farid,
Volume 20, Issue 1 (March 2023)
Abstract
In this paper, Pb1-xFex(Zr0.52Ti0.48)O3 (PFZT) nanopowders, with x from 0.00 up to 0.20, were synthesized by using the sol-gel method. The PFZT samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and impedance spectroscopy. According to the experimental results, PFZT combines rhombohedral and tetragonal symmetries for all the samples without a change in phase structure. The SEM investigation indicated that the grains are homogeneous with regular form and the average grain size of PFZT ceramics changed with Fe concentration. The dielectric characterizations show that the dielectric permittivity increases with increasing temperature, and the Fe amount shifts down the temperature of transition. Moreover, a dielectric resonance phenomenon is observed for all the PFZT ceramics.
Ahabboud Malika, Gouitaa Najwa, Ahjyaje Fatimazahra, Lamcharfi Taj-Dine, Abdi Farid, Haddad Mustapha,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
This paper reports the preparation and characterization of (1-x) PbZr0.52Ti0.48O3 -xBiFeO3 (1-x)PZTxBFO) (x= 0.00, 0.15, 0.30, 0.45, 0.60 and 1.00) multiferroic ceramics which were prepared by a sol-gel method for PZT and hydrothermal reaction process for BFO. The perovskite structure of the composite system was confirmed by X-ray diffraction and Raman spectroscopy, while the composite microstructure w:as char:acterized by scanning electron microscopy. XRD results and Rietveld analysis for the (1-x)PZT-xBFO composites confirm the coexistence of these three phases; rhombohedral (R3m) and tetragonal phases (P4mm) for pure PZT and only the rhombohedral phase (R3c) for pure BFO. Raman spectroscopy of the (1-x)PZT-xBFO composites shows two clear bands around 150 and 180 cm-1. When the BFO content increases, the intensities of Raman modes are decreased. The SEM results suggested a formation of agglomerate and form into large complex clusters as BFO increased and a higher grain size was obtained for the BFO sample compared with the other composites. The EDS spectra of our pellets show that all the characteristic lines of the chemical elements Pb, Zr, Ti, and O and Bi, Fe, and O are present for the PZT and BFO materials respectively. The temperature-dependent dielectric constant shows different behavior dependent on BFO content. Indeed, the dielectric properties are found to be improved with an increase in dopant concentration of BFO in PZT, and novel dielectric behavior, resonance, and antiresonance, were obtained.
