Publications Internationales

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1,4-Dimethoxybutadienediyl-Bridged diiron compounds in three oxidation states : evaluation of delocalization effects
(American Chemical Society, 2019) Sahnoune, Hiba; Mahias, Virginie; Halet, Jean-François; Lapinte, Claude
The binuclear iron complexes [Cp∗(PMe3)(CO)Fe-C(OCH3)=CH-CH=C(OCH3)-Fe(PMe3)(CO)Cp∗] (1meso and 1dl) were prepared by double deprotonation of their known parents [Cp∗(PMe3)(CO)Fe=C(OCH3)CH2-CH2-C(OCH3)=Fe(PMe3)(CO)Cp∗](PF6)2 (5meso and 5dl) and were isolated in good yield (90%). These complexes were characterized by ESI-mass spectrometry, IR and multinuclear NMR spectroscopy, and cyclic voltammetry. The singly and doubly oxidized forms 1meso(PF6)n and 1dl(PF6)n (n = 1, 2) were prepared by oxidation of the parent neutral complexes with 1 and 2 equiv of ferrocenium salt (93-100% yield). The related complex [Cp∗(dppe)Fe-C(OCH3)=CH-CH=C(OCH3)-Fe(dppe)Cp∗](PF6) (2(PF6)) was obtained by reduction of the known dicationic derivative [Cp∗(dppe)Fe-C(OCH3)=CH-CH=C(OCH3)-Fe(dppe)Cp∗](PF6) (2(PF6)2) with 1 equiv of cobaltocene (100% yield). Multinuclear NMR spectroscopy allowed us to establish the diiron(II) conjugated μ-bis(carbene) structure for 1meso(PF6)2 and 1dl(PF6)2. In the case of the meso derivative, 1H NMR revealed the presence of E and Z isomers in a 4:1 ratio, confirming the presence of a C=C double bond in the middle of the bridge. The three radicals 1meso(PF6), 1dl(PF6), and 2(PF6), which are thermally stable, were analyzed by IR, Mössbauer, ESR, UV-vis, and NIR spectroscopy. Experimental data, discussed with the support of quantum chemistry calculations performed at the DFT level of theory, indicate that these radical cations exhibit characteristics of oxidation on the butadienediyl bridge rather than on the metal centers
2,4-Substituted-3-aza-1-thiabutadienes : a conformational study by dipolmetry
(Elsevier, 1992) Cellerin, C.; Abouelfida, A.; Pradère, J.P.; Proutière, A.; Rozé, J.C.; Bouzid, Mohammed; Exner, O.
A 2.3-14 GHz UWB planar octagonal antenna with modified ground plane
(Wiley Periodicals, 2013) Bitchikh, M.; Aksas, R.; Azrar, Arab; Kimouche, H.
2D-DOA Estimation performance using split vertical linear and circular arrays
(John Wiley & Sons, 2016) Aouina, Karima; Benazzouz, Djamel
This paper presents a new approach to reduce the computational complexity in two-dimensional (2D) matrix pencil (MP) method for direction of arrival (DOA) estimation of plane wave signals using a combination of vertical uniform linear array (VULA) and uniform circular array (UCA). By applying phase mode excitation based beamforming to the UCA, we can apply the matrix pencil (MP) method to the beamspace data using only a single snapshot. The technique is based on the split array, which is composed of two perpendicular arrays. The vertical uniform linear array used to determine the elevation DOA components is located perpendicularly at the center of the uniform circular array in the horizontal plane used to calculate the azimuth angles. Unlike common planar and circular arrays, this antenna array with its particular geometry requires no pair-matching between the azimuth and the elevation angle estimation and can also remove the drawbacks of estimation failure problems. Using this particular geometry for the 2D MP method leads to an efficient computational methodology for real-time implementation on a digital signal processor. The obtained simulation results of the MP method applied to both uncorrelated and correlated narrowband sources in the presence of white noise show good performance estimation
3-Methoxycarpachromene and Masticadienonic Acid as New Target Inhibitors from Pistacia atlantica Leaves against Trypanothione Reductase of Leishmania Parasites: In Vitro and In Silico Studies
(2021) Maamri, Sarra; Benarous, Khedidja; Yousfi, Mohamed
This study aimed to identify new drug molecules against Leishmania parasites, leishmaniasis's causal agent, using Pistacia atlantica leaves as source. The evaluation of the anti-leishmania potential against the promastigote form of Leishmania. infantum and Leishmania. major was performed. A new in silico study was accomplished using molecular docking, with Autodock vina program, to find the binding affinity of two important phytochemical compounds from this plant (Masticadienonic acid, 3-Methoxycarpachromene) towards the trypanothione reductase as target drugs, responsible for defence mechanism against oxidative stress and virulence of this parasites. Results: Several concentrations showed a significant decrease in cell viability (P<0.0001), with IC50 values of 0.3 mg/ mL for L. infantum and 0.12 mg/ mL L. major; The molecular docking confirms the significant relationship between Leishmania survival and the inhibition of this crucial enzyme. There were promising and new positive results on binding modes of selected ligands and the trypanothione reductase for the first time. Through this work, we propose 3-Methoxycarpachromene and Masticadienonic acid as anti Trypanosomatidae species drug.
3D anisotropic stress analysis during kyropoulos growth of sapphire single crystal
(Wiley, 2019) Zermout, S.; Mokhtari, Faiza; Nehari, A.; Lasloudji, I.; Haddad, F.; Merah, A.
By using 3D finite element calculations, numerical simulations are performed to predict the thermal field as well as the thermal stress in a c‐axis sapphire single crystal grown by Kyropoulos technique. The effects of additional resistive heating (placed under the crucible bottom) and crystal rotation are investigated and a comparison is made between the isotropic and anisotropic analysis. The anisotropy of the elastic constants and thermal expansion coefficients as well as their temperature dependence are considered in the anisotropy calculations while Young's modulus and the Poisson ratio are used in the isotropic analysis. Thermal stress is found to be smaller in the anisotropy analysis than that in the isotropic analysis and significant differences are found in their respective distribution patterns. Additional resistive heating acts to decrease both of the crystal–melt interface convexity and the von Mises stress. In addition, crystal rotation combined with additional resistive heating decreases significantly the thermal stress inside the sapphire crystal and along the melt–crystal interface. Therefore, optimizing the heating conditions and using a suitable crystal rotation rate seem to be favorable to control the growth interface shape and to reduce thermal‐stress‐related defects during the growth process
A 3D DEM-LBM approach for the assessment of the quick condition for sands = Approche couplée DEM-LBM 3D de prédiction de la boulance des sables
(Elsevier, 2009) Mansouri, M.; Delenne, J.-Y.; El Youssoufi, M.S.; Seridi, A.
3D numerical and experimental modelling of multiphase flow through an annular geometry applied for cuttings transport
(Elsevier, 2022) Ferroudji, Hicham; Rahman, Mohammad Azizur; Hadjadj, Ahmed; Ofei, Titus Ntow; Khaled, Mohamed Shafik; Rushd, Sayeed; Gajbhiye, Rahul Narayanrao
Accurate estimation of volume fraction and pressure gradient is considered indicating parameters of efficient cuttings transportation. It is vital, in this regard, to consider all parameters that can affect cuttings volume fraction and pressure drop during enrollment of the drilling process. The analysis was conducted based on the turbulent flow of a power-law fluid through an annular domain by employing the Finite Volume Method. In addition, dimensional relationships were developed with the Buckingham-π theorem. Before carrying out simulations, the numerical schemes were validated using actual measurements made with the flow loop system available in Texas A&M University at Qatar. The simulation results demonstrated the followings: (i) using a power-law type drilling fluid with a shear-thinning character would reduce energy consumption for an inclination greater than 45°; (ii) inclination angles from 45° to 60° would be least desirable for an effective cuttings transportation with a turbulent Ostwald-de Waele fluid
3D Numerical investigation of asphalt pavements behaviour using infinite elements
(World Academy of Science, Engineering and Technology (WASET), 2017) Sandjak, Khaled; Tiliouine, Boualem
This article presents the main results of three-dimensional numerical investigation of asphalt pavement structures behaviour using a coupled Finite Element-Mapped Infinite Element (FE-MIE) model. The validation and numerical performance of this model are assessed by confronting critical pavement responses with Burmister’s solution and FEM simulation results for multi-layered elastic structures. The coupled model is then efficiently utilised to perform (3-D) simulations of a typical asphalt pavement structure in order to investigate the impact of two tire configurations (conventional dual and new generation wide-base tires) on critical pavement response parameters. The numerical results obtained show the effectiveness and the accuracy of the coupled (FE-MIE) model. In addition, the simulation results indicate that, compared with conventional dual tire assembly, single wide base tire caused slightly greater fatigue asphalt cracking and subgrade rutting potentials and can thus be utilised in view of its potential to provide numerous mechanical, economic and environmental benefits
3D Numerical study of magnetohydrodynamic instability in liquid metal taylor-couette flow
(2015) Merah, Abdelkrim; Mokhtari, Faiza; Bouabdallah, A.; Adnane, M.
This purpose is about a 3D study of magnetohydrodynamic (MHD) instability in liquid matal Taylor-Couette flow, this problem is receiving more and more research interest due to its application in the engineering, oceanography and the astrophysical research The Taylor-Couette system consists of two coaxial cylinders in differential rotation, which is considered as a hydrodynamic model system, allowed researchers to progress in understanding the laminar-turbulent transition phenomena. A set of states found in narrow gap of Taylor-Couette systems where the outer cylinder is held fixed and the inner cylinder speed increased. The symmetry breaking parameter is the Taylor number Ta that gives a measure of the ratio of centrifugal forces to viscous forces. When the liquid is replaced by an electrically conducting fluid and an external magnetic field is applied, this leads to MHD Taylor-Couette flow. Additional body force, Lorentz force, acting on the fluid arises. Lorentz force is in the direction perpendicular to both magnetic and electric fields. The behaviour of flow depends on strength and geometry of applied field, magnetic and electric properties of the liquid, cylinders and endplates. In this work, the MHD instability Taylor-Couette flow is considered for liquid sodium with its magnetic Prandtl number Pm <1. The results of pressure and angular momentum in the Taylor-Couette flow under the effect of an external uniform axial magnetic field B=4 Tesla are investigated numerically for the different cases of electrically conducting or insulating walls at the Ekman cell, at the middle of the first Taylor-votex flow (TVF) and between two cells.
3D structural cartography based on magnetic and gravity data inversion - Case of South-West Algeria
(Elsevier, 2015) Boubekri, Hichem; Hamoudi, Mohamed; Bendaoud, Abderrahmane; Priezzhev, Ivan
Ab initio investigations of magnetic properties of FeCo monolayer alloy films on Rh(001)
(2012) Blizak, S.; Bihlmayer, G.; Blügel, S.
The objective of this work is to employ spin-polarized density functional theory (sDFT) calculations for the exploration of ultrathin magnetic films with large magnetic moments and a strong perpendicular anisotropy. Monolayer films of Fe1−xCox (with x=0, 0.25, 0.5, 0.75, and 1) on Rh(001) were addressed to study their magnetic properties using the all-electron full-potential linearized augmented plane wave (FLAPW) method in film geometry. We studied the magnetic order of these films including structural relaxations of the topmost layers. Fe1−xCox monolayer films were found to be ferromagnetic (FM) in a broad range of Co content x with a maximum magnetic moment of 2.8 μB and of an out-of-plane magneto-crystalline anisotropy of 0.25 meV per magnetic atom at x=0.5. The sDFT results were mapped onto a classical Heisenberg model, demonstrating FM Fe-Co and Co-Co couplings, while the Fe-Fe interaction is antiferromagnetic on Rh(001). The ordering temperature of the FeCo film was estimated to be well above room temperature (482 K)
Ab intio investigation of electronic and magnetic properties of Ca1-x TMx Te (TM = V, Cr, and Mn)
(2021) Daoudi, Youcef; Mazouz, Hadj Moulay Ahmed; Fadla, Mohamed Abdelilah; Benghia, Ali
The interesting characteristics of spintronics exhibit lower energy consumption, higher density, push up us to find new materials that can be functional for spintronics such as half metallic ferromagnets. Based on density functional theory (DFT) and using full potential linearized augmented plane waves and local orbitals (FP-LAPW + lo) method implemented in Wien2k package, we carried out a study of structural, electronic and magnetic properties of CaTe doped with V, Cr, and Mn for various concentrations namely x = 0.25, 0.125, and 0.0625. Tran-Blaha-modified Beck-Johnson potential (TB-MBJ) was used to investigate the electronic and magnetic properties. We found that: only Cr-doped compounds are half metallic ferromagnetic materials with 100% spin-polarisation at Fermi level (Ef) and their ferromagnetism stabilization maybe explained by Zener's double exchange mechanism. An integer integrated total magnetic moment per TM atom marked to be 3,4, and 5 in Bohr magneton(μB) for V, Cr, and Mn-doped compounds respectively. We found large half metallic gaps for Cr dopant compounds resulting from the strong p-d hybridization of 5p (Te) and 3d (Cr), which make them promising candidates for spintronic devices and applications
Ability of spatial filters to distinguish between two MUAPs generated from MUs with different locations, sizes and fibers pennation
(IOP Publishing, 2023) Messaoudi, Noureddine; Belkacem, Samia; Bekka, Raïs El’hadi
In this study, we investigated the effects of the motor unit (MU) location and size and the fibres pennation on the ability of anisotropic and almost isotropic spatial filters used to detect surface electromyographic (EMG) signals to make a distinction between motor unit action potentials (MUAPs) generated from two MUs. The study was based on simulated MUAPs. The fibres orientation was performed by varying the fibres pennation angle (FPA). The root mean square error (RMSE) between MUAPs generated from two MUs was used as a criterion to evaluate the ability of the investigated filters to distinguish between two generated MUAPs. The location of a MU was fixed and the second MU moved away from the first MU in the transversal direction for the first case and in the depth direction in the second case to take five different locations in every case. We showed that the capability of the studied filters to more separate two MUAPs strongly depended on MU location, MU size and FPA. This capability of separation was best with large distances between the two MUs and with large sizes of them. Furthermore, the main survey of this work was that the BiTDD filter has the best ability of separation of two MUAPs than the other filters in a given FPA interval. The number of pennation angles in this interval is related to the location and size of the moved MU
Absence of dynamical crossover in the vortex creep near by the second peak e ect in superconducting Hg-1201 single crystals
(Springer, 2000) Daignere, A.; Aouaroun, T.; Simon, C.
Absorption performances of PLA-Montmorillonite nanocomposites thin films in salisbury and rozanov configurations : influence of aging and mechanical recycling
(MDPI, 2023) Sidi Salah, Lakhdar; Ouslimani, Nassira; Danlée, Yann; Huynen, Isabelle
The present paper aims to address the crucial concern of pollution induced by growing plastic waste and electromagnetic interference (EMI). Nanocomposites combining poly(lactic acid) (PLA) and organo-modified montmorillonite (OMMT) are synthesized and compression molded into thin films. A first set of samples, referred as virgin, was kept as is, while a second set of samples were photochemically, thermally and hydrolytically aged before mechanical recycling via extruding and second compression molding, resulting in the so-called recycled composite. The electromagnetic (EM) properties with a focus on microwave absorption performances of virgin and recycled samples are compared for various thicknesses and weight concentrations of OMMT in PLA matrix. The EM performances are gauges by Rozanov and Salisbury structures that consist in one- and two-layer stacks of composite films back-coated by a metal foil. Characterization in Rozanov configuration shows an average absorption index over the Ka band of 29.3% and 21.1% for, respectively, virgin and recycled PLA reinforced with 4 wt.% OMMT. An optimization of the film thickness is proposed; up to 61.85% and 80% of absorption with a thickness of 1.4 mm and 3.75 mm, respectively, is reached with a metal back-coated rPLA-4%OMMT film. Characterization in Salisbury configuration gives advantage to the recycled structure with an average absorption of 49.6% for a total thickness of 1.4 mm. The requirements of EMI shielding are met by PLA-OMMT composites with a certain benefit of recycling process on EM performance
AC Loads Supply Continuity in Connected and Islanded Microgrids Systems
(2023) Kaddour, Djillali; Belaidi, Hadjira; Belaidi, Dehia; Faouzi, Didi
In the pursuit of establishing a sustainable and highly reliable microgrid, the continual operation and system dependability in both grid-connected and islanded configurations emerge as paramount objectives. Our vision centers on the implementation of an intelligent Energy Management System (EMS), complemented by cutting-edge optimization techniques and well-suitable resource sizing. These synergistic components empower the microgrid to adeptly manage peak demands, surmounting even the most adverse weather conditions, all the while liberating it from external resources or any additional draw from the grid facility. Conducting a compelling case study, we delve into the efficiency of our EMS algorithm, thoughtfully realized through MATLAB Simulink, by analyzing pertinent load profiles and power consumption data from buildings within our esteemed institution, IGEE (Institute of Electrical and Electronic Engineering). To transcend the confines of conventional grid-tied PV systems Inverter, we ingeniously propose a novel approach, coordinating a Diesel Generator-Photovoltaic panel (DG-PV) synchronization, thereby seamlessly enabling the grid-tied PV system to function in off-grid scenarios. This concept lies in achieving optimal performance through the deployment of uniform Distributed Energy Resources (DERs) sizes for Photovoltaic (PV) and Battery Energy Storage Systems (BESS) in both grid-connected and islanded modes. Supplemented by sophisticated control algorithms and real-time monitoring, the microgrid flawlessly transits between operational modes, ensuring unrivaled efficiency and unwavering dependability.
Acaricidal activity of flavonoids extract of Borago officinalis L. (Boraginaceae) against brown dog tick, Rhipicephalus sanguineus (Latreille, 1806)
(Tropical Biomedicine, 2018) EL Haddad, Djillali; Bitam, I.; Bouchenak, Ouahiba; Toubal, S.; Yahiaoui, Karima; Arab, K.; Boumaza, S.
Borago officinalis L. (Boraginaceae) is a plant of the Boraginaceae family, used in Algeria for food and medicinal purposes. This study reports the effect of flavonoids extracted from the aerial part of Borago officinalis L. (Boraginaceae) on the larvae and engorged adult females of the brown dog tick Rhipicephalus sanguineus (Latreille, 1806) using adults immersion test (AIT) and larval immersion test (LIT). For this purpose, the larvae and engorged female of Rhipicephalus sanguineus (Latreille, 1806) were exposed to serial dilutions of flavonoids extract (50 mg/ml, 25 mg/ml, 12.5 mg/ml and 6.25 mg/ml) using “dipping method” in vitro. The plant extract was obtained by fractionation using appropriate solvents. The extraction yield is 22% with a flavonoids concentration equal to 129.12 μg equivalent of quercetin/ml of the extract. The chromatographic analysis by high performance thin layer chromatography (HPTLC) reveals the presence of gallic acid, vanillic acid, kaempferol, dihydroxybenzoic and quercetin. The results obtained show that the flavonoids extract of Borago officunalis L. (Boraginaceae) considerably reduces the oviposition and the hatching rate of the eggs of Rhipicephalus sanguineus (Latreille, 1806) and was shown to be toxic against newly hatched larvae of Rhipicephalus sanguineus (Latreille, 1806) (P < 0.05)
Accurate asymmetrical minor loops modeling with the modified arctangent hysteresis model
(Elsevier, 2024) Birouche, Chafik; Hamel, Meziane; Nait Ouslimane, Ahmed; Fellag, Ratiba; Zaouia, Mustapha
In the area of automotive propulsion, electric motors experience core losses due to the presence of higher harmonic frequencies, particularly those arising from pulse width modulation switching. Consequently, it is required to establish a practical model capable of characterizing the hysteresis loops in electrical steel when subjected to harmonic excitations. Nonetheless, existing dynamic models may be inappropriate for real-world applications due to their inherent complexity and their tendency to neglect the influence of minor loops arising from harmonics. In the present work, the minor and major hysteresis curves of non-oriented silicon steel sheets are measured under variable frequency excitation containing harmonic components. To reproduce the asymmetrical minor hysteresis loops, a modified arctangent model is employed. The evaluation of the accuracy of this hysteresis model is conducted by comparing the fitted results of static and dynamic hysteresis loops against experimental data, both with and without harmonic excitation.
An accurate combination of on-the-fly interface trap and threshold voltage methods for NBTI degradation extraction
(Springer, 2014) Tahanout, Cherifa; Tahi, Hakim; Djezzar, Boualem; Benabdelmomene, Abdelmadjid; Goudjil, Mohamed; Nadji, Becharia