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LMI solutions for H-two and H-infinity decentralized controllers applied to an aerothermic process

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控制理论与应用（英文版） 2013年第2期11卷 247-254页

作者： Najib BENNIS mustapha RAMZI Mohamed HALOUA Hussein YOULAL ENSET de Rabat Avenue de l'Arme'e Royale Madinat Al Irfane 10100 B. P. 6207 Rabat-InstitutsMorocco LASTIMI EST de sale' Universite' Mohamed V Agdal Avenue Prince sidi Mohammed B.P 227 Sale' Me'dinaMorocco EMI Avenue IbnSina B. P. 765 Agdal RabatMorocco UFR Automatique et Technologies de l'Information Faculte' des Sciences de Rabat Avenue Ibn Batouta B. P. 1014 RabatMorocco

In this paper, we present a linear matrix inequality （LMI）-based solution to implement H-two and H- infinity decentralized robust control strategies. Appropriate parametrization of optimal H-two and H-infinity controllers is used. The general formulation of the decentralized control design leads to the optimal determination of both the state feedback gains and the observer gains of the decentralized controllers. This formulation is two folds： first, a centralized controller is obtained, and then, a simplified decentralized solution is derived by optimizing only the observer gains. The mathematical determination of these gains is formulated as an LMI optimization problem that can be easily solved using LMI solvers. As an experimental evaluation of these controllers, a real time application to an aerothermic process is carried out. A continuous-time model of the process obtained with a suitable direct continuous-time identification approach is elaborated. Results illustrating the real performance obtained from the H-two and H-infinity decentralized controllers are di^cu^ge.d and comnare, d with th~ ce^ntraliTed nn^g

关键词： Parametrization approach Decentralized control H-two/H-infinity control Parameters optimization Lin-ear matrix inequality (LMI) Subspace identification Aerothermic process

Preoperative biliary drainage for resectable or borderline resectable periampullary tumor: what is the best management?

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Hepatobiliary Surgery and Nutrition 2019年第4期8卷 398-400页

作者： Julie Perinel mustapha Adham Service de chirurgie Digestive Hopital Edouard HerriotHospices Civils de LyonLyonFrance Faculte de Medecine de Lyon Universite Claude Bernard Lyon 1(UCBL1)LyonFrance

Management of preoperative biliary drainage (PBD) in patients undergoing pancreaticoduodenectomy (PD) is still debated. Obstructive jaundice is associated with a proinflammatory state, impaired immune function and disturbances in coagulation. Patients with jaundice are at high risk to develop renal dysfunction and bacteriobilia. In this context, PBD was traditionally performed before surgery to improve postoperative outcomes.

关键词： impaired biliary jaundice

Epithelial cells with hepatobiliary phenotype:Is it another stem cell candidate for healthy adult human liver?

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World Journal of Gastroenterology 2007年第10期13卷 1554-1560页

作者： Dung Ngoc Khuu mustapha Najimi Etienne M Sokal Université Catholique de Louvain Laboratory of Pediatric Hepatology & Cell therapyBrusselsBelgium

AIM： To investigate the presence and role of liver epithelial cells in the healthy human adult liver. METHODS： Fifteen days after human hepatocyte primary culture, epithelial like cells emerged and started proliferating. Cell colonies were isolated and sub- cultured for more than 160 d under specific culture conditions. Cells were analyzed for each passage using immunofluorescence, flow cytometry and reverse transcription-polymerase chain reaction （RT-PCR）. RESULTS： Flow cytometry analysis demonstrated that liver epithelial cells expressed common markers for hepatic and stem cells such as CD90, CD44 and CD29 but were negative for CD34 and CDl17. Using immunofluorescence we demonstrated that liver epithelial cells expressed not only immature （α-fetoprotein） but also differentiated hepatocyte （albumin and CK-18） and biliary markers （CK-7 and 19）, whereas they were negative for OV-6. RT-PCR analysis confirmed immunofluorescence data and revealed that liver epithelial cells did not express mature hepatocyte markers such as CYP2B6, CYP3A4 and tyrosine amino-transferase. Purified liver epithelial cells were transplanted into SCID mice. One month after transplantation, albumin positive cell foci were detected in the recipient mouse parenchyma. CONCLUSION： According to their immature and bipotential phenotype, liver epithelial cells might represent a pool of precursors in the healthy human adult liver other than oval cells.

关键词： Epithelial-like cells Liver stem cell Hepatocyte Differentiation Cell therapy

An improved algorithm for mapping burnt areas in the Mediterranean forest landscape of Morocco

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Journal of Forestry Research 2019年第3期30卷 981-992页

作者： Issameddine Zidane Rachid Lhissou Abdelali Bouli mustapha Mabrouki Environment and Valorisation of Agro-resource Laboratory Faculty of Science and TechnologySultan Moulay Slimane UniversityB.O.523Beni MellalMorocco Team of Remote Sensing and GIS Applied to Geosciences and Environment Faculty of Science and TechnologySultan Moulay Slimane UniversityB.O.523Beni MellalMorocco Industrial Engineering Laboratory Faculty of Science and TechnologySultan Moulay Slimane University B.O.523Beni MellalMorocco

The identification of burnt forests and their monitoring provide essential information for the suitable management and conservation of these ecosystems. This research focuses on the use of remote sensing with MODIS sensor data in a Mediterranean environment, precisely in the Rif region known for its high occurrence of forest fires and the largest burnt areas in Morocco. It mapped the burnt areas during the summer of 2016 using spectral indices from MODIS images, namely the Normalized Burn Ratio (NBR) and the Burnt Area Index for MODIS (BAIM). Two field surveys were used to calibrate spectral indices and validate the maps. First, a monotemporal analysis using a single pre-fire image determined the appropriate threshold of the spectral indices (BAIM and NBR) for burn detecting. Secondly, a multitemporal method was applied based on dBAIM and dNBR images which represented pre-fire and postfire differences of the BAIM and NBR images, respectively. The results show that separate use of monotemporal postfire and multitemporal methods produced an overestimation of the burnt areas. Finally, we propose a new algorithm combining both methods for burnt area mapping that we name Burnt Area Algorithm. MCD45A1 and MCD64A1 MODIS burnt area products were compared to the proposed algorithm. Validation of the estimated burnt areas using reference data of the Moroccan High Commission for Water, Forests and Fight against Desertification showed satisfactory results using the proposed algorithm, with a determination coefficient of 0.68 and a root mean square error of 44.0 ha.

关键词： Burnt forest mapping Threshold MODIS MCD45A1 MCD64A1 Spectral indices Morocco

Sliding mode approach applied to sensorless direct torque control of cage asynchronous motor via multi-level inverter

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Protection and Control of Modern Power Systems 2020年第1期5卷 166-175页

作者： Soukaina El Daoudi Loubna Lazrak mustapha Ait Lafkih Laboratory of Automatic Energy Conversion and MicroelectronicsFaculty of Sciences and TechnologySultan Moulay Slimane UniversityBeni MellalMorocco

To improve the robustness and performance of the dynamic response of a cage asynchronous motor,a direct torque control(DTC)based on sliding mode control(SMC)is adopted to replace traditional proportional-integral(PI)and hysteresis *** combination of the proposed strategy with sinusoidal pulse width modulation(SPWM)applied to a three-level neutral point clamped(NPC)inverter brings many advantages such as a reduction in harmonics,and precise and rapid tracking of the *** are performed for a three-level inverter with SM-DTC,a two-level inverter with SM-DTC and the three-level inverter with *** results show that the SM-DTC method achieves better performance in terms of reference tracking,while adoption of the threelevel inverter topology can effectively reduce the *** the SM-DTC to the three-level inverter presents the best solution for achieving efficient and robust *** addition,the use of a sliding mode speed estimator eliminates the mechanical sensor and this increases the reliability of the system.

关键词： Asynchronous cage motor Direct torque control Sinusoidal pulse width modulation Sliding mode control Speed estimator Three-level inverter

Hepatocyte cryopreservation:Is it time to change the strategy?

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World Journal of Gastroenterology 2010年第1期16卷 1-14页

作者： Xavier Stéphenne mustapha Najimi Etienne M Sokal Catholic University of Louvain and St Luc Clinics Paediatric Department(HPED)PEDI unitLaboratory of Paediatric Hepatology and Cell Therapy

Liver cell transplantation presents clinical benefit in patients with inborn errors of metabolism as an alternative,or at least as a bridge,to orthotopic liver *** success of such a therapeutic approach remains limited by the quality of the transplanted *** remains the best option for long-term storage of hepatocytes,providing a permanent and sufficient cell ***, isolated adult hepatocytes are poorly resistant to such a process,with a significant alteration both at the morphological and functional ***,the aim of the current review is to discuss the state of the art regarding widely-used hepatocyte cryopreservation protocols,as well as the assays performed to analyse the post-thawing cell quality both in vitro and in vivo. The majority of studies agree upon the poor quality and efficiency of cryopreserved/thawed hepatocytes as compared to freshly isolated *** ice formation or exposure to hyperosmotic solutionsremains the main phenomenon of cryopreservation process,and its effects on cell quality and cell death induction will be *** increased knowledge and understanding of the cryopreservation process will lead to research strategies to improve the viability and the quality of the cell suspensions after *** strategies,such as vitrification,will be discussed with respect to their potential to significantly improve the quality of cell suspensions dedicated to liver cell-based therapies.

关键词： Hepatocyte Cryopreservation Quality Mitochondria Intracellular ice formation

Amplitude and Period Effect on Heat Transfer in an Enclosure with Sinusoidal Heating from Below Using Lattice Boltzmann Method

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Frontiers in Heat and Mass Transfer 2023年第1期21卷 523-537页

作者： Noureddine Abouricha Chouaib Ennawaoui mustapha El Alami LABSIPE National School of Applied SciencesChouaib Doukkali UniversityEl Jadida24000Morocco Green Tech Institute(GTI) Mohammed VI Polytechnic University(UM6P)Benguerir43150Morocco LPMMAT Department of PhysicsFaculty of SciencesHassan II University of CasablancaCasablanca20100Morocco

This work presents a simulation of the phenomena of natural convection in an enclosure with a variable heating regime by the lattice Boltzmann method(LBM).We consider a square enclosure of side H filled with air(Pr=0.71)and heated from below,with a hot portion of length L=0.8 H,by imposing a sinusoidal *** unheated segments of the bottom wall are treated as adiabatic,and one of the vertical walls features a cold region,while the remaining walls remain *** outcomes of the two-dimensional(2D)problem are depicted through isotherms,streamlines,the temperature evolution within the enclosure,and the Nusselt *** visualizations span various amplitude values“a”in the interval[0.2,0.8],and of the period T0 for Ra=*** amplitude and period effect on the results is evaluated and *** amplitude of the temperature at the heart of the enclosure increases with the increase in *** also increases with the period(T0)of the imposed temperature,something that is not observable on the global Nusselt number.

关键词： Sinusoidal heating square cavity lattice Boltzmann method natural convection heat transfer under floor heating

Experimental Study of Heat Transfer in an Insulated Local Heated fromBelow and Comparison with Simulation by Lattice Boltzmann Method

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Frontiers in Heat and Mass Transfer 2024年第1期22卷 359-375页

作者： Noureddine Abouricha Ayoub Gounni mustapha El Alami LABSIPE National School of Applied SciencesChouaib Doukkali UniversityEl Jadida24000Morocco LPMAT Department of PhysicsFaculty of SciencesHassan II University of CasablancaCasablanca20100Morocco

In this paper,experimental and numerical studies of heat transfer in a test local of side H=0.8 m heated from below are presented and *** the walls,the rest of the floor and the ceiling are made from plywood and polystyrene in sandwich form(3 mmplywood-3 cm polystyrene-3 mmplywood)just on one of the vertical walls contained a glazed door(2 H/3×0.15 m).This local is heated during two heating cycles by a square plate of iron the width L=0.6 H,which represents the heat source,its temperature Th is *** plate is heated for two cycles by an adjustable set-point heat source placed just down the center of *** each cycle,the heat source is switched“on”for 6 h and switched“off”for 6 *** outdoor air temperature is kept constant at a low temperature Tc<*** measurements are carried out with k-type thermocouples and with flux *** will be qualitatively presented for two cycles of heating in terms of temperatures and heat flux densitiesϕfor various positions of the test *** temperature evolution of the center and the profile of the temperature along the vertical centerline are compared by two dimensions simulation using the lattice Boltzmann *** comparison shows a good agreement with a difference that does not exceed±1℃.

关键词： Experimental study numerical study lattice Boltzmann method heat transfer building insulation thermal comfort

Modeling of fiber bridging in fluid flow for well stimulation applications

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Petroleum Science 2020年第3期17卷 671-686页

作者： Mehdi Ghommem mustapha Abbad Gallyam Aidagulov Steve Dyer Dominic Brady Department of Mechanical Engineering American University of ShaijahSharjah 26666United Arab Emirates Schlumberger Dhahran Carbonate Research Center Dammam/Doha Camp 31942Kingdom of Saudi Arabia Schlumberger Completions RosharonTX 77583USA

Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation *** materials(fibers and solid particles)have recently shown a good capability as fluid diversion to overcome the issues related to matrix *** the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism,it was observed that the volume of the base fluid and the loading of the particles are not *** current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular *** is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and *** modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development,new applications of existing products or usage *** this work,we develop a numerical model to study fiber dynamics in fluid *** employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected *** discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous *** focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in *** trends of the dynamic fiber behavior under various operating conditions including fiber loading,flow rate and fluid viscosity obtained from the numerical model show consistency with experimental *** present numerical investigation reveals that the bridging capability of the fi

关键词： Fiber bridging Fiber flocculation Modeling and numerical simulation Discrete element method Fiber-fluid coupling Sensitivity analysis