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61.
Mohamed Zbair Zkaria Anfar Hamza Khallok Mohamed Ezahri Noureddine Elalem 《Fullerenes, Nanotubes and Carbon Nanostructures》2018,26(7):433-442
In this work, Sawdust was used to develop a new low-cost adsorbent and study its application to remove methylene blue dye from aqueous solution. Sawdust was calcined under air atmosphere at three different temperatures (300°C, 400°C, and 500°C) using phosphoric acid (H3PO4) as an activating agent. The structure, morphology, surface functions and the chemical composition of adsorbent were characterized by Fourier Transform Infrared spectra (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), specific surface area (BET) and Boehm method. Different operational parameters such as pH, adsorbent loading, contact time and were investigated to evaluate experimental data. The adsorption of MB on SD-300, SD-400, and SD-500 show that the pseudo-second-order and Langmuir models fitted better the experimental results of MB adsorption onto all adsorbents. The maximum capacities based on the Langmuir model were 416.7 mg.g?1 for SD-300, 526.3 mg.g?1 for SD-400, and 819.7 mg.g?1 for SD-500. The positive values of ΔG, ΔH, and ΔS implied that the adsorption process was non-spontaneous and endothermic nature. Finally, Regeneration of the SD-500 was investigated and optimization was performed using CCD combined with RSM. 相似文献
62.
Nadia Chagtmi Noureddine Boulejfen Weiwei Zhang Abul Hassan Christian Fager Fadhel M. Ghannouchi 《国际射频与微波计算机辅助工程杂志》2019,29(2)
Two architectures of concurrent dual‐band six‐port‐based receiver (SPR), which are modeled and calibrated using the augmented Hammerstein model (AHM) are proposed for the first time in this article. The receivers are based on six‐port junctions with one or two local oscillators (LO). The proposed single step calibration algorithms achieve the recovery of the two in‐phase (I1 and I2) and quadrature (Q1 and Q2) components of an RF signal with two frequency components (RF1 and RF2). Experimental validations have been performed to verify the performance of the proposed concurrent dual‐band receivers and to test the efficiency of the AHM based calibration algorithms. As a performance metric, the Error Vector Magnitude (EVM) has been measured to compare the transmitted and recovered baseband signals and to evaluate the performance and efficiency of the proposed calibration algorithms for the two receiver topologies. The IQ data has been recovered with EVMs no higher than 2% for the two LOs based receiver excited with a QAM modulated dual‐band RF signal. The single LO based receiver has been tested with a dual‐band LTE signal and the recovered IQ data exhibited EVMs no higher than 4%. 相似文献
63.
Pattern Analysis and Applications - Tracking objects is an important field for many applications like driving assistance and video surveillance. Every tracking system should be able to track... 相似文献
64.
Radhouane Bel Hadj Tahar Noureddine Bel Hadj Tahar 《Journal of the American Ceramic Society》2005,88(7):1725-1728
Novel sol–gel processes for the preparation of grain-oriented thin films of pure and aluminum-doped zinc oxide (AZO) are reported. Using various stabilizing ligands, oxide films with different degree of c -axis orientation could be prepared on amorphous substrates. The origin of orientation in sol–gel-derived ZnO and AZO films is investigated. The texture selection of ZnO films is independent of the heat-treatment schedule but sensitive to the precursor system. The electrical properties of the films do not depend significantly on the crystallographic orientation. The film visible transmittance remained higher than 90% even after vacuum annealing. 相似文献
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68.
Noureddine Barka Ahmed Chebak Abderrazak El Ouafi Mohammad Jahazi Abdellah Menou 《Journal of Materials Engineering and Performance》2014,23(9):3092-3099
The beneficial effects of using flux concentrators during induction heat treatment process of spur gears made of 4340 high strength steel is demonstrated using 3D finite element model. The model is developed by coupling electromagnetic field and heat transfer equations and simulated by using Comsol software. Based on an adequate formulation and taking into account material properties and process parameters, the model allows calculating temperature distribution in the gear tooth. A new approach is proposed to reduce the electromagnetic edge effect in the gear teeth which allows achieving optimum hardness profile after induction heat treatment. In the proposed method, the principal gear is positioned in sandwich between two other gears having the same geometry that act as flux concentrators. The gap between the gear and the flux concentrators was optimized by studying temperature variation between the tip and root regions of gear teeth. Using the proposed model, it was possible identifying processing conditions that allow for quasi-uniform final temperature profile in the medium and high frequency conditions during induction hardening of spur gears. 相似文献
69.
Anne‐Claude Courbaron Gilbert Laurent Billon Noureddine El Bounia Christophe Derail 《Polymer International》2013,62(4):616-620
The influence of carbon nanotubes on various chemical reactions has been examined. These reactions include epoxy crosslinking, in situ polymerization of copolymers in the presence of carbon nanotubes and thermal degradation of a thermoplastic matrix. The various characterizations were based on different types of analyses, including differential scanning calorimetry, proton nuclear magnetic resonance, size exclusion chromatography and thermogravimetric analysis. In each case, we show that the presence of multi‐walled carbon nanotubes accelerates the process. © 2012 Society of Chemical Industry 相似文献
70.
Noureddine Barka Ali Assabbane Abederrahman Nounah Larbi Laanab Yhya Aît Ichou 《Desalination》2009,235(1-3):264-275
The objective of this study was to investigate the ability of natural phosphate (NP) to remove textile dyes from aqueous solutions. The adsorption of methylene blue (MB) as a reference molecule for the adsorption studies of organic molecules, basic yellow 28 (BY 28) and reactive yellow 125 (RY 125) representatives of two families of textile dyes was studied in a batch mode. The experimental results show that NP can totally remove MB and BY 28, whereas a low adsorption affinity was found in the case of RY 125. The adsorption rate data were analysed using the pseudo-first order kinetics of Lagergren and the pseudo second order model to determine adsorption rate constants. The isotherms of adsorption data were analyzed by various adsorption isotherm models. The adsorption was temperature- and pH-dependent with a high adsorption capacity of MB and BY 28 in the basic range and a high adsorption of RY125 in an acidic range. 相似文献