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Local nonlinear unknown input observer

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控制理论与应用（英文版） 2013年第3期11卷 517-520页

作者： ramzi ben messaoud Mekki KSOURI Department of Electrical Engineering National Engineering School of TunisBox 37 1002 Tunis Tunisia

This paper proposes a new nonlinear unknown input observer. The observer design approach utilizes the first order Taylor expansion. The observer gains are then obtained by a systematic method. In this paper, we added some improvements to this method. The developed approach also can enable observer design for a large class of differentiable nonlinear systems. The necessary and sufficient conditions for the existence of the observer are given. A numerical example is given to illustrate the attractiveness and the simplicity of the new design procedure.

关键词： Unknown inputs observers Stability Nonlinear systems Robust and state estimation

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Optimal Systematic Determination of Models' Base for Multimodel Representation: Real Time Application

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International Journal of Automation and computing 2014年第6期11卷 644-652页

作者： Majda Ltaief Anis messaoud Ridha ben Abdennour Research Unit of Numerical Control of Industrial Processes National School of Engineers of Gabes University of Gabes St Omar Ibn El-Khattab6029 Gabes Tunisia

The multimodel approach is a powerful and practical tool to deal with analysis, modeling, observation, emulation and control of complex systems. In the modeling framework, we propose in this paper a new method for optimal systematic determination of models base for multimodel representation. This method is based on the classification of data set picked out of the considered system. The obtained cluster centers are exploited to provide the weighting functions and to deduce the corresponding dispersions and their models base. A simulation example and an experimental validation on a semi-batch reactor are presented to evaluate the effectiveness of the proposed method.

关键词： Multimodel approach identification classification weighting functions complex systems chemical reactor

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Relationship between high sensitivity C-reactive protein and angiographic severity of coronary artery disease

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Journal of Geriatric Cardiology 2020年第5期17卷 256-263页

作者： Nadia Bouzidi Mejdi ben messaoud Faouzi Maatouk Habib Gamra Salima Ferchichi University of Monastir Faculty of PharmacyClinical and Molecular Biology UnitMonastirTunisia University of Monastir Cardiology A Department Fattouma Bourguiba University HospitalCardiothrombosis Research LaboratoryTunisia University of Monastir Cardiology B Department Fattouma Bourguiba University HospitalCardiothrombosis Research LaboratoryTunisia

Background Coronary artery disease(CAD)remains a leading cause of morbidity and *** play a potential role in atherosclerosis pathogenesis and *** investigated the association between high sensitive C-reactive protein(hs CRP)and severity of *** CAD patients were stratified according to hs CRP cut-off value into high levels hs CRP group(≥8.4 mg/L)and low levels hs CRP group(<8.4 mg/L).Severity of CAD was assessed according to artery stenosis degree and the number of vessel *** analysis was performed using Statistical Package for the Social Sciences(SPSS,version 23.0).Results The mean age was 60.3±11.0 *** level of hs CRP was increased and ranged from 0.2 to 1020.0 mg/*** risk factors and severity of CAD didn’t show significant differences between the two *** multivariate linear analysis,cardiac troponin I(c Tn I)and serum amyloid A(SAA)were predictors of hs *** shown in receiver operating characteristic(ROC)curve analysis performed in patients with ST-segment elevation myocardial infarction(STEMI)and compared to myonecrosis biomarkers,hs CRP(area under the curve(AUC):0.905;95%CI:0.844-0.966;P<0.001)could be a powerful predictor marker in evaluating the infarct size after myocardial infarction but not better than c Tn *** Hs CRP levels were not associated with the severity of CAD but could be useful in the evaluation of myocardial necrosis in patients with STEMI.

关键词： Coronary artery disease High sensitive C-reactive protein Severity

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Effect of temperature and pH value on cation exchange performance of a natural clay for selective(Cu2+,Co2+) removal:Equilibrium,sorption and kinetics

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Progress in Natural Science:Materials International 2013年第1期23卷 23-35页

作者： ramzi Chalghaf Walid Oueslati Marwa Ammar Hafsia ben Rhaiem Abdesslem ben Haj Amara UR05/13-01:Physique des Matériaux Lamellaires et Nanomatériaux Hybrides(PMLNMH) Facultédes Sciences de BizerteZarzouna 7021Tunisia

This work aims at investigating the strain effect,created by varying pH solution and continuous heating cycle,on the cation exchange process in the case of Na-rich montmorillonite sample in contact with bi-ionic solution with variable concentration,saturated respectively by Co2+ and Cu2+ *** ionic exchange process is characterized using XRD analysis obtained through the comparison of experimental XRD patterns with calculated ones,which allowed us to determine several structural parameters related to the nature,abundance,size,position and organization of exchangeable cation and water molecule in the interlamellar space along the ***,the proposed theoretical models,for the stressed samples,show that the structure presents an interstratified hydration character and proves the coexistence of more than two ''crystallite'' specie in the *** perturbation types have an obvious effect on the selective exchange process for all stressed samples,where the interlayer space is characterized by the coexistence of more one exchangeable cation.

关键词： Geological membrane Soil decontamination Alkaline strain Thermal stress Quantitative XRD analysis Ionic exchange process

Crystallochemical Characterizations, Raman Spectroscopy and Studies Nuclear Magnetic Resonance (NMR) of Cu<sub>2</sub>Zn(Sn, Si)S<sub>4 </sub>Compounds for Photovoltaic Applications

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Journal of Materials Science and Chemical Engineering 2022年第1期10卷 24-40页

作者： Mohamed Hamdi messaoud benamira Northern Border University Arar Turaif Saudi Arabia Laboratory of Interaction Materials and Environment (LIME) University of Mohamed Seddik Ben Yahia-Jijel Jijel Algeria

In this study, Si-doped Cu2ZnSnS4 compounds (Cu2ZnSn1-xSixS4, 0 ≤ x ≤ 1) were prepared by solid state reaction method for use of materials for photovoltaic cells. The structural and spectroscopic properties of the as-prepared compounds were studied by X-ray diffraction (XRD), 119Sn, 29Si and 65Cu Magic Angle Spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The Si-substitution in the Sn-site induces three different types of XRD patterns which depend largely on the Si content in the compound. For 0 ≤ x ≤ 0.5, XRD analysis reveals the presence of a pure tetragonal phase of solid solution with I-42m as a space group. Mixed tetragonal and orthorhombic phases were observed for 0.5 1 at high content of Si (x ≥ 0.8). 119Sn MAS NMR spectra show the presence of Sn/Si disorder as a function of the Si content. The 65Cu MAS NMR spectra of the quadratic solid solution confirm the presence of the two copper sites (Cu-2a and Cu-2c) at 780 ppm while in the case of the orthorhombic solid solution samples, a very broad band is observed. The optical properties were investigated of all compounds by UV-Vis diffuse reflectance and the obtained optical band gap values (1.31 to 2.43 eV) confirm a semiconductor character.

关键词： Photovoltaic Cells Cu2ZnSnS4 Nuclear Magnetic Resonance Raman Spectroscopy