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<i>Acacia trotilis</i>and <i>Calotropis procera</i>: Do They Substantially Promote Soil Carbon Sequestration?

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Open Journal of Soil Science 2012年第2期2卷 116-122页

作者： taoufik Saleh Ksiksi Department of Biology Faculty of Science UAE University Al-Ain UAE

Very little is known about the type and mix of desert plant species and their management to optimize carbon sequestration in desert ecosystems. Overgrazing is one important practice that affects soil carbon cycling and therefore sequestration. Improving soil carbon in desert ecosystems may be best through the use of native trees and shrubs. Acacia tortilis and calotropis procera are two important species in the United Arab Emirates (UAE). The former is a native species that improves biodiversity and the latter is not native and has been reported to be an indicator of overgrazing. The average soil organic matter (SOM) content was higher in soils dominated by A. tortilis when compared to those dominated by C. procera;2.98 and 1.34;respectively (P 2 emission.

关键词： Desert Soils Nutrient Cycling Soil Carbon

Modeling of Radiating Aperture Using the Iterative Method

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Detection 2022年第3期9卷 29-36页

作者： Rafika Mejri taoufik Aguili Communication System Laboratory Sys’Com National Engineering School of Tunis University Tunis El Manar Tunis Tunisia

We are interested in this work to electromagnetic leakage, for example the door of the microwave oven (or shielding of electronic functions working in the microwave band containing holes for ventilation circuit) which must be transparent (chain link) but the level of electromagnetic leakage issued by this device must not exceed certain standards. This work started with this article in which we are interested in a simple structure consisting of a multilayer structure incorporating a radiating aperture. We show in this paper mainly the interests of this study and the limitations of using these structures. Modeling of this device is provided by the wave concept iterative procedure (WCIP) which is simple to implement and is characterized by the fast execution method. The validation of our work is carried out by comparing our results with those calculated by the Ansoft HFSS software which shows a good agreement.

关键词： Electromagnetic Leakage Radiating Aperture Microwave Iterative Method Planar Structure Multilayer Electromagnetic Shielding

Rigorous Electromagnetic Modeling of a Micro Strip Line Incorporating a Flat and Thick Metallic Conductor Based on the Skin Effect Phenomenon

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Open Journal of Metal 2022年第1期12卷 1-9页

作者： Rafika Mejri taoufik Aguili Communication System Laboratory Sys’Com National Engineering School of Tunis University Tunis El Manar Tunis Tunisia

In most studies of microstrip circuits, the majority of researchers assume that the microstrip structures studied have flat metallic conductors of finite widths but without thickness. But in reality these types of structures integrate metallic copper conductors of different thicknesses. If we neglect this thickness we introduce error in the electrical parameters of the microstrip structure, which affects the effective permittivity, the characteristic impedance, the adaptation of the circuit, the resonance frequency, etc. Given the importance of this parameter (thickness of the metal of micro rubon structures), rigorous electromagnetic modeling of the thick micro rubon line based on the skin effect phenomenon (In fact at high frequency the skin effect phenomenon occurs and the current only flows on the periphery of the conductor) has been proposed to improve the studied electric model and ensure the increase in the precision of the analysis method used: Wave concept iterative process. The good agreement between the simulated and published data justifies the improvement of the model.

关键词： Micro Strip Line Thick Conductor WCIP Skin Effect Phenomenon

A New Approach Based on Iterative Method for the Characterization of a Micro-Strip Line with Thick Copper Conductor

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Journal of Electromagnetic Analysis and Applications 2016年第5期8卷 95-108页

作者： Rafika Mejri taoufik Aguili Communication System Laboratory Sys’Com National Engineering School of Tunis University Tunis El Manar Tunis Tunisia

In this work, we applied two electromagnetic models for the characterization of a planar structure including a flat, thick copper conductor. Indeed the first model is consisted by modeling two metal ribbons without bulkiness, placed one above the other at a distance of h2 equal to the thickness of the thick conductor. This approach has been implemented and tested by the iterative method. The results of simulations have been compared with those calculated by the Ansoft HFSS software, and they are in good concordance, validating the method of analysis used. The second model is based on the calculation of the effective permittivity of the medium containing the thick conductor. This medium consists of a metallic region of complex relative permittivity , the rest of this medium is filled with air er2 = 1. The effective permittivity eeff calculated from these two relative permittivity er2 and . Comparing the simulation results of this new formulation of the iterative method with those calculated by the software Ansoft HFSS shows that they are in good matching which validates the second model.

关键词： Thick Conductor Iterative Method Micro-Strip Line Microwaves Skin Effect Phenomenon Effective Permittivity

Friction welding influence on microstructure,microhardness and hardness behavior of CrNiMo steel(AISI 316)

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China Welding 2023年第3期32卷 21-27页

作者： Ammar Jabbar Hassan Billel Cheniti Brahim Belkessa taoufik Boukharouba Djamel Miroud Nacer-Eddine Titouche Advanced Mechanics Laboratory(LMA) Houari Boumediene University of Sciences and TechnologyEl Alia 16111Bab EzzouarAlgiersAlgeria Research Center in Industrial Technologies Algiers 16014Algeria Science and Engineering Materials Laboratory(LSGM) Houari Boumediene University of Sciences and TechnologyEl Alia 16111Bab EzzouarAlgiersAlgeria Birine Nuclear Research Center Ain OusseraDjelfa 17200Algeria

For joining high Cr,Ni and Mo austenitic stainless steel(AISI 316)by direct drive friction welding(DDFW),with friction weld-ing conditions:rotation speed of 3000 r/min,friction time of 10 s,friction pressure of 130 MPa,forge time of 5 s and forge pressure of 260 *** results of microstructure showed that the temperature at the interface reached 819℃while forge applied between 357-237℃,which subdivided welded joint into four distinct regions of highly plastically deformed zone(HPDZ),thermo-mechanically affected zone(TMAZ),heat affected zone(HAZ)and the base metal,with grain size about 10µm,100µm,90µm and 30µm *** re-gions were created due to dynamic recrystallization(DRX)at the interface and thermo-mechanical deformation with heat diffusion in the neighboring ***,high level of microhardness about 300 HV0.1 and hardness roughly 240 Hv10 at the interface due to HPDZ creation while low level of 240 HV0.1 for microhardness and moderately of 205 HV10 for hardness in neighboring regions.

关键词： friction welding austenitic stainless steel microstructure microhardness hardness

New Formulation of the Mulilayer Iterative Method: Application to Coplanar Lines with Thick Conductor

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Journal of Electromagnetic Analysis and Applications 2016年第9期8卷 197-218页

作者： Rafika Mejri taoufik Aguili Communication System Laboratory Sys’Com National Engineering School of Tunis University of Tunis El Manar Tunis Tunisia

The skin effect is an electromagnetic phenomenon that makes the current flows only on the surface of the conductors at high frequency. This article is based on the phenomenon to model a structure made in coplanar technology. In reality, these types of structures integrated metal layers of different thickness of copper (9 μm, 18 μm, 35 μm, 70 μm). The neglect of this parameter introduces errors, sometimes significant, in the numerical calculations. This is why an iterative method (FWCIP) based on the wave concept was restated. Validation of results was carried out by comparison with those calculated by Ansoft HFSS software and Agilent ADS Technology. They show a good matching.

关键词： Skin Effect Electromagnetic Phenomenon Iterative Method Coplanar Structure Microwave

Optimization of Coupled Periodic Antenna Using Genetic Algorithm with Floquet Modal Analysis and MoM-GEC

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Open Journal of Antennas and Propagation 2022年第1期10卷 1-15页

作者： Nader Ben Latifa taoufik Aguili Laboratory of the Communication Systems National Engineering School of Tunis Le Belv&#233 dè re Tunis Tunisia

In this paper Genetic Algorithm has been integrated with Fouquet modal analysis to optimize radiation pattern of coupled periodic antenna. Floquet analysis is used with MoM-GEC (Moment-Generalized Equivalent Circuit) method to study a finite periodic array with uniform amplitude and linear phase distribution. This method is very advantageous for studying large antenna array since it considerably reduces the computation time and the number of operations. In this way, Genetic algorithm is introduced and combined with Floquet analysis to optimize the radiation pattern distribution of this coupled periodic antenna. The goal of the optimization is to provide a better radiation characteristic for the coupled periodic antenna with maximum side lobe level reduction.

关键词： Periodic Antenna Floquet Analysis MoM-GEC Method Genetic Algorithm

New Formula for Evaluating the Number of Unit Cell of a Finite Periodic Structure Considered as Infinite Periodic One

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Journal of Electromagnetic Analysis and Applications 2011年第9期3卷 343-350页

作者： Samia Bouali taoufik Aguili 不详

This paper presents a modeling and an analysis of one-dimensional periodic structure composed of a cascade connection of N cells considered as infinite. The ABCD matrix representations with the Floquet analysis have been used to derive the dispersion relation and input impedance of infinite periodic structure. The transmission matrix for the N identical cascaded cells has been successfully used to obtain an efficient and easy-to-use formula giving the necessary number of cells such that they can be considered infinite. As an illustrative example, the formula is applied and verified to finite size TL periodically loaded with obstacles. Scattering parameters and the input impedance of the structure are expressed and plotted.

关键词： Periodic Structure Floquet Theorem Dispersion Relation Scattering Parameters Input Impedance

Finite Step Conjugate Gradients Methods for the Solution of an Impedance Operator Equation Arising in Electromagnetics

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Journal of Electromagnetic Analysis and Applications 2011年第10期3卷 416-422页

作者： Haifa belhadj taoufik Aguili 不详

A class of finite step iterative methods, conjugate gradients, for the solution of an operator equation, is presented on this paper to solve electromagnetic scattering. The method of generalized equivalent circuit is used to model the problem and then deduce an electromagnetic equation based on the impedance operator. Four versions of the conjugate gradient method are presented and numerical results for an iris structure are given, to illustrate convergence properties of each version. Computational efficiency of these methods has been compared to the moment method.

关键词： Conjugate Gradient method Generalized Equivalent Circuit Method MoM Electromagnetic Computational Scattering