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Use of Large-Eddy Simulation for the bed shear stress estimation over a dune

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International Journal of Sediment Research 2021年第6期36卷 687-695页

作者： Adrien Bourgoin Sylvain S.Guillou Jér?me Thiébot Riadh Ata normandy University University of Caen Normandy normandy University University of Caen Normand

Environmental flows are generally characterized by complex bed morphology and high current *** configurations favor the formation of vortex structures that strongly affect hydrody-namics and sediment transport. Large-Eddy Simulation(LES) enables investigation of the dynam-ics of the largest turbulence scales and, thanks to enhanced calculation resources, has now become applicable for simulating environmental flows. In this paper, a LES approach is developed in a CFD code(TELEMAC-3 D),which was originally developed to simulate free surface flows using RANS methods. The present developments involve implementing subgrid models, boundary con-ditions and numerical schemes suitable for LES. The LES version of TELEMAC-3 D was validated by comparing results on the model with experimental data for flow past a cylinder. Then, the model was applied to a test case representing flow over dunes. After validating the hydrodynamics, the model was used to assess the bottom shear stress,using both a RANS and a LES approach. Com-parison highlighted the potential contribution of LES to investigating the hydrodynamic forces acting on the bottom.

关键词： Turbulence Environmental flows Large eddy simulations Bed shear stress

Exploration, explanation and exploitation of hydroxyls in zeolites

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National Science Review 2022年第9期9卷 8-9页

作者： Eddy Dib Edwin B.Clatworthy Hugo Cruchade Izabel C.Medeiros-Costa Nikolai Nesterenko Jean-Pierre Gilson Svetlana Mintova Laboratory of Catalysis and Spectrochemistry(LCS) Normandy University National Graduate School of Engineering of Caen(ENSICAEN) French National Center for Scientific Research(CNRS) Total Energies Research and Technology

The ideal crystalline framework of zeolites is perturbed by hydroxyl groups. In pure silica zeolites the framework is neutral, however, the introduction of Al3+into the Si4+oxide framework creates negative charges, giving rise to Br?nsted acid sites (BASs). O?ten referred to as bridged hydroxyls [Si–O(H)–Al], they are formed when a proton is bound to one of the oxygens adjacent to an aluminum.

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Impact of the blockage ratio on the transport of sediment in the presence of a hydrokinetic turbine: Numerical modeling of the interaction sediment and turbine

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International Journal of Sediment Research 2021年第6期36卷 696-710页

作者： Fatima Khaled Sylvain Guillou Yann Méar Ferhat Hadri University of Caen normandy LISV University of Versailles Conservatoire National des Arts et Métiers University of Caen Normandy

Interactions between hydrokinetic turbines and near scale and far scale bed sediment particles are considered a critical area of assessment; however, a limited number of research studies have been published to address this issue. The current paper explores the influence of the blockage ratio on the morphology evolution downstream from a hydrokinetic turbine. A modeling framework is derived to predict the significant transport induced by a turbine installed on the erodible fluvial sandy bed surface,such as the Eulerian multi-phase model for the sediment and the Blade Element Momentum Theory(BEMT) for the turbine, using the open source platform OpenFOAM. Two configurations of different blockage ratios are considered. The configurations show differences in the bed morphology and the sediment transport. It has been shown for both configurations that the scour capabilities are enhanced below the turbine due to the acceleration of the flow and increasing local shear stress on the sediment.

关键词： Environmental impact Blockage effects Euler-Euler multiphase Hydrokinetic turbine Numerical simulations OpenFOAM

Filtered High Gain Observer for an Electric Vehicle’s Electro-hydraulic Brake: Design and Optimization Using Multivariable Newton-based Extremum Seeking

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Chinese Journal of Electrical Engineering 2023年第4期9卷 73-87页

作者： Jamal El-bakkouri Hamid Ouadi Fouad Giri Mohamed Khafallah ENSEM Hassan II University of CasablancaCasablanca BP 8118Morocco ENSAM Rabat Mohammed V UniversityRabat BP 6207Morocco Department of Electrical Engineering University of Caen NormandyCaen 14032France

Designing high-gain observers(HGOs)for the state estimation of an electric vehicle’s electrohydraulic brake(EHB)system is *** type of observer is applicable to model nonlinearities and constant feature ***,they are very sensitive to measurement noise,which is unavoidable in *** first novelty of this study is that it compensates for the measurement noise using a filtered high-gain observer(FHGO)to ensure EHB state *** proposed FHGO provides an estimate of the master cylinder pressure,motor current,and rotor speed from measurements of the rotor *** second novelty is the design of an extremum-seeking(ES)optimization loop to adjust the FHGO gains *** performance of the developed FHGO with ES-based online gain optimization was highlighted in the presence of model uncertainties and output measurement noise using a Matlab/Simulink *** superiority of the FHGO(even with a fixed gain)over a standard high gain observer(SHGO)was also demonstrated.

关键词： Electrohydraulic brake filtered HGO measurement noise optimization extremum-seeking Lyapunov theory

Transradial coronary rotational atherectomy using 5-French guiding catheters

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Chinese Medical Journal 2009年第11期122卷 1356-1358页

作者： Marouane Allouch Zhong Yu Zhu John W. Riddell Remi Sabatier Martial Hamon Department of Cardiology CHU de Caen Normandy France

Transradial coronary stenting using 5-French （5F） guiding catheters has been associated with a higher procedural success rate, a lower frequency of vascular access complications and is well tolerated, particularly i... 详细信息

关键词： rotational atherectomy radial artery elderly

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Detection of CO2 and O2 by iron loaded LTL zeolite films

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Frontiers of Chemical Science and Engineering 2018年第1期12卷 94-102页

作者： Veselina Georgieva Richard Retoux Valerie Ruaux Valentin Valtchev Svetlana Mintova Laboratoire Catalyse et Spectrochimie (LCS) ENSICAEN CNRS Normandy University 14000 Caen France Laboratoire de Cristallographie et Sciences des Matériaux (CRISMAT) ENSICAEN CNRS Normandy University 14000 Caen France

Detection of oxygen and carbon dioxide is important in the field of chemical and biosensors for atmosphere and biosystem monitoring and fermentation processes. The present study reports on the preparation of zeolite films doped with iron nanoparticles for detection of CO2 and O2 in gas phase. Pure nanosized LTL type zeolite with monomodal particle size distribution loaded with iron （Fe-LTL） was prepared under hydrothermal condition from colloidal precursor suspensions. The zeolite was loaded with iron to different levels by ion exchange. The Fe-LTL suspensions were used for preparation of thin films on silicon wafers via spin coating method. The reduction of the iron in the zeolite films was carried out under H2 flow （50% H2 in Ar） at 300 ℃. The presence of iron nanoparticles is proved by in situ ultra-violet-visible spectroscopy. The properties of the films including surface roughness, thickness, porosity, and mechanical stability were studied. In addition, the loading and distribution of iron in the zeolite films were investigated. The Fe-LTL zeolite films were used to detect O2 and CO2 in a concentration dependent mode, followed by IR spectroscopy. The changes in the IR bands at 855 and 642 cm^-1 （Fe O-H and Fe-O bending vibrations） and at 2363 and 2333 cm^-1 （CO2 asymmetric stretching） corresponding to the presence of O2 and CO2, respectively, were evaluated. The response to O2 and CO2 was instant, which was attributed to great accessibility of the iron in the nanosized zeolite crystals. The saturation of the Fe-LTL films with CO2 and O2 at each concentration was reached within less than a minute. The Fe-LTL films detected both oxygen and carbon dioxide in contrast, to the pure LTL zeolite film.

关键词： zeolite films detection of CO2 and O2 adsorption

Chemical characterization of fine and ultrafine PM, direct and indirect genotoxicity of PM and their organic extracts on pulmonary cells

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Journal of Environmental Sciences 2018年第9期30卷 168-178页

作者： Sylvain Billet Yann Landkocz Perrine J. Martin Anthony Verdin Frederic Ledoux Capucine Lepers Veronique Andre Fabrice Cazier Francois Sichel Pirouz Shirali Pierre Gosset Dominique Courcot University of the Littoral Opal Coast Unit of Environmental Chmistry and Interactions with Liuing Organisms UCEIV EA4492 SFR Condorcet FR CNRS 3417 Dunkerque France normandy uniu UNICAEN ABTE EA4651 Caen France University of the Littoral Opal Coast Common Centre of Measurements CCM Dunkerque France Centre Francois Baclesse Caen France Department of Anatomy and Pathological Cytologly Saint-Vincent Hospital Catholic Hospital Lille France

Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed by studying physico-chemical characteristics and mechanisms involved in the toxicity of particulate atmospheric pollution. PM0.3-2.s and PM2.5 including ultrafine particles were sampled in Dunkerque, a French industrialized seaside city. PM samples were characterized from a chemical and toxicological point of view. Physico-chemical characterization evidenced that PM2.5 comes from several sources： natural ones, such as soil resuspension and marine sea-salt emissions, as well as anthropogenic ones, such as shipping traffic, road traffic, and industrial activities. Human BEAS-2B tung cells were exposed to PM0.3-2.5, or to the Extractable Organic Matter （EOM） of PM0.3-2.5 and PM2.s. These exposures induced several mechanisms of action implied in the genotoxicity, such as oxidative DNA adducts and DNA Damage Response. The toxicity of PM-EOM was higher for the sample including the ultrafine fraction （PM2.5） containing also higher concentrations of polycyclic aromatic hydrocarbons. These results evidenced the major role of organic compounds in the toxicity of PM.

关键词： Air pollution particulate matter PM2.5 Ultrafine particles Physico-chemical characterization Biotransformation Genotoxicity

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The Interactions Between“Business”Culture,“Professional”Culture and Training

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Journal of Sociology Study 2023年第5期13卷 215-241页

作者： Robert Messanh Amavi CIRNEF Normandy UniversityNormandyFrance

Ultimately,the fundamental issues of educational sciences remain economic and *** interactions between“business”culture,“professional”culture and training are part of *** contribution is a reflection resulting from a longitudinal empirical research entitled:“Professionalization of an establishment in the social and medico-social field:a French monograph after the law 2002-02 of January 02,2002”.Three concepts were used:“making sense”(Weick,1995);the“strategic paradigm”(Jonhson,1987);and“cultures of action”(Sorel&Wittorski,2005;Barbier,2010;Ardouin,2015).

关键词： business culture professional training development making sense

The Mechanical and Crystallographic Evolution of Stipa tenacissima Leaves During In-Soil Biodegradation

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Journal of Renewable Materials 2018年第3期6卷 336-346页

作者： Zakia Khelifi Mohammed Amine Allal Nabil Abou-bekr Said Taibi Benoit Duchemin normandy University ULHCNRSLOMC76600 Le HavreFrance University of Tlemcen Lab-EOLEBP 23013000 TlemcenAlgeria

The in-soil biodegradation of Stipa tenacissima(alfa)leaves was ***-linear mechanical testing was performed at various biodegradation *** strength,loading and unloading Young’s moduli and dissipation energy decreased with the burial time,whereas plasticity ***-emission scanning electron microscopy(FE-SEM)showed that the fracture cracks propagated in the longitudinal direction in the raw material,resulting in a fracture mode consisting of a mixture of middle lamella delamination and fiber *** contrast,the cracks were perpendicular to the stem axis in the biodegraded material,demonstrating an important strength loss of the load-bearing *** strength loss was correlated with rapid cellulose degradation.A novel X-ray diffraction(XRD)model was implemented in order to take into account anisotropic size *** the first time,XRD demonstrated the action of biodegradation on unrefined plant tissues under quasi in-situ *** induced a progressive loss of crystalline cellulose accompanied with anisotropic crystallite thinning.

关键词： Alfa mechanical testing FE-SEM XRD biodegradation