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Existence and numerical approximation of a solution to frictional contact problem for electro-elastic materials

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 201-219页

作者： Othman Baiz el-Hassan Benkhira rachid Fakhar University Ibn Zohr Lab.ESERFP of OuarzazateMorocco University Moulay Ismail Faculty of SciencesLaboratory MACSESTMBP 3103Toulal-MeknesMorocco University Sultan Moulay Slimane Laboratory LS2MEPolydisciplary Faculty of Khouribga25000 KhouribgaMorocco

In this paper,a frictional contact problem between an electro-elastic body and an electrically conductive foundation is *** contact is modeled by normal compliance with finite penetration and a version of Coulomb’s law of dry friction in which the coefficient of friction depends on the *** addition,the effects of the electrical conductivity of the foundation are taken into *** model leads to a coupled system of the quasi-variational inequality of the elliptic type for the displacement and the nonlinear variational equation for the electric *** existence of a weak solution is proved by using an abstract result for elliptic variational inequalities and a fixed point ***,a finite element approximation of the problem is *** some regularity conditions,an optimal order error estimate of the approximate solution is ***,a successive iteration technique is used to solve the problem numerically and a convergence result is established.

关键词： piezoelectric material frictional contact variational Inequality fixed point process finite element method error estimation iteration method

TWO DISJOINT AND INFINITE SETS OF SOLUTIONS FOR AN elLIPTIC EQUATION INVOLVING CRITICAL HARDY-SOBOLEV EXPONENTS

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Acta Mathematica Scientia 2023年第5期43卷 2061-2074页

作者： Khalid BOUABID rachid ECHARGHAOUI Mohssine el MANSOUR Department of Mathematics Faculty of SciencesIbn Tofail UniversityKenitraB.P.133Morocco

In this paper,by an approximating argument,we obtain two disjoint and infinite sets of solutions for the following elliptic equation with critical Hardy-Sobolev exponents■whereΩis a smooth bounded domain in RN with 0∈?Ωand all the principle curvatures of?Ωat 0 are negative,a∈C1(Ω,R*+),μ>0,02(q+1)/(q-1).By2*:=2N/(N-2)and 2*(s):(2(N-s))/(N-2)we denote the critical Sobolev exponent and Hardy-Sobolev exponent,respectively.

关键词： Laplacien critical Sobolev-Hardy exponent critical Sobolev exponent infinitely many solutions Pohozaev identity

Analysis of Convective Heat Exchanges and Fluid Dynamics in the Air Gap of a Discoid Technology Rotary Machine

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Frontiers in Heat and Mass Transfer 2024年第3期22卷 733-746页

作者： Abdellatif el Hannaoui rachid Boutarfa Chadia Haidar Mechanical Engineering Industrial Management and Innovation LaboratoryFaculty of Science and TechniquesHassan 1st UniversitySettatMorocco Department of Energy Laboratory University Moulay IsmailENSAMMeknèsMorocco

The proposedwork focuses on the in-depth study of convective heat transfer in the unconfined air gap of a discoidal rotor-stator *** rotary cooling mechanism is achieved by the injection of two air jets,while the cavity geometry is characterized by a dimensionless parameter *** numerical analysis primarily concentrated on the effect of flow velocity and rotation on the heat exchange *** precisely,the range of analysis extends from the rotational Reynolds number Re_(ω)=2.35×10^(5)to Re_(ω)=5.04×10^(5),while varying the Reynolds value of the jet in a range from 16×10^(3)to 55.46×10^(3).To carry out this analysis,a numerical simulation was conducted with Ansys-Fluent software,using the RSM turbulence *** results of the study significantly reveal the impact of rotation on heat exchange transfer within the cavity,identifying two distinct zones of fluid *** zones exhibit remarkable heat transfer characteristics,contributing to a better understanding of the complexmechanisms governing heat transfer in this particular technological ***,the analysis of radial mean velocity distributions,as well as local and mean Nusselt numbers,provides further insight into the heat transfer performance of this unique configuration.

关键词： Heat transfer rotor-stator impacting jets RSM turbulence model

pH-indicative Films Based on Chitosan–PVA/Sepiolite and Anthocyanin from Red Cabbage: Application in Milk Packaging

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Journal of Bionic Engineering 2022年第3期19卷 837-851页

作者： Marya Raji Laila el Foujji Mohamed el Mehdi Mekhzoum Mounir el Achaby Hamid Essabir rachid Bouhfid Abou el kacem Qaiss Moroccan Foundation for Advanced Science Innovation and ResearchComposites and Nanocomposites CenterRabat Design CenterRue Mohamed El JazouliMadinat El IrfaneRabat10100Morocco Faculty of Science Laboratoire de Chimie Organique Et HétérocycliqueUniversity Mohammed V in RabatRabat10100Morocco Materials Science and Nano-Engineering Department Mohammed VI Polytechnic UniversityLot 660–Hay Moulay RachidBen Guerir43150Morocco Mechanic Materialsand Composites(MMC)Laboratory of Energy EngineeringMaterials and SystemsNational School of Applied Sciences of AgadirIbn Zohr UniversityAgadir80000Morocco

Biobased smart packaging is been the most interesting research *** this study,pH-sensitive films based on anthocyanin molecules from red cabbage and sepiolite mineral nano-clay as functional additives were *** films were fabricated by casting method of blend polymer Chitosan/Poly(Vinyl Alcohol)at two fillers loading(5wt.%and 10wt.%).The structural,morphological,thermal,optical,hygroscopic,and mechanical properties as well as the pH sensitivity of films were *** thermal properties confirm that the amount of the anthocyanin in sepiolite was around 6.4%.The tensile strength and the young’s modulus of produced composites at 10wt.%sepiolite–anthocyanin content was increased to 8.90 MPa and 163 MPa,*** maximum water absorption that the films may absorb was 12.3%.pH sensitivity analysis showed that the Smart films change the color by changing the pH level,from pink at pH lower than 6 to yellow at pH higher than ***,the developed pH-sensitive films show band gaps in visible light that make them useful for monitoring milk spoilage.

关键词： Smart packaging Anthocyanin Red cabbage pH-sensitive and milk spoilage

New insights into the cardio-renal benefits of SGLT2 inhibitors and the coordinated role of miR-30 family

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Genes & Diseases 2024年第6期11卷 205-220页

作者： Abdellatif el Khayari Soukaina Miya Hakam Gabriel Malka Luc Rochette rachid el Fatimy Institute of Biological Sciences(ISSB-P) UM6P Faculty of Medical SciencesMohammed VI Polytechnic University(UM6P)Ben-Guerir 43150Morocco Equipe d'Accueil(EA 7460):Physiopathologie et Epidemiologie Cerebro-Cardiovasculaires(PEC2) Universite de Bourgogne-Franche ComteFaculte des Sciences de Sante7 Bd Jeanne d'ArcDijon 21000France

Sodium-glucose co-transporter inhibitors(SGLTis)are the latest class of anti-hyper-glycemic *** addition to inhibiting the absorption of glucose by the kidney causing glycosuria,these drugs also demonstrate cardio-renal benefits in diabetic ***-30 family,one of the most abundant microRNAs in the heart,has recently been linked to a setting of cardiovascular diseases and has been proposed as novel biomarkers in kidney dysfunctions as well;their expression is consistently dysregulated in a variety of cardio-renal *** mechanistic involvement and the potential interplay between miR-30 and SGLT2i effects have yet to be thoroughly *** research has stressed the relevance of this clus-ter of microRNAs as modulators of several pathological processes in the heart and kidneys,raising the possibility of these small ncRNAs playing a central role in various cardiovascular complications,notably,endothelial dysfunction and pathological ***,we review current evidence supporting the pleiotropic effects of SGLT2is in cardiovascular and renal out-comes and investigate the link and the coordinated implication of the miR-30 family in endo-thelial dysfunction and cardiac *** also discuss the emerging role of circulating miR-30 as non-invasive biomarkers and attractive therapeutic targets for cardiovascular dis-eases and kidney *** evidence,as well as metabolic,cellular,and molecular as-pects,arecomprehensively covered.

关键词： Cardiac remodeling Cardiovascular diseases Endothelial dysfunction Kidney miR-30 SGLT2 inhibitor

Thermal energy performance of compressed earth building in two different cities in Moroccan semi-arid climate

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Energy and Built Environment 2024年第5期5卷 800-816页

作者： Marouane Wakil Hicham el Mghari Samir Idrissi Kaitouni rachid el Amraoui Laboratory of Energy Engineering and Materials(LEEM) Faculty of Sciences and TechnologiesSultan Moulay Slimane UniversityCampus MghilaBP 523CP 23000Beni MellalMorocco Green Energy Park(IRESEN&UM6P) BenguerirMorocco Research Team:Materials Environment and Sustainable Development(MEDD)Faculty of Sciences and Techniques of TangierAbdelmalek Essaadi UniversityTangier BP 416Morocco

The assessment of the thermal energy performance of earth-based buildings with respect to the semi-arid Mediter-ranean climate of Morocco is scarce,even if the country is historically known for its earthen *** to this need,this work aims to understand and evaluate the indoor thermal comfort and energy performances of passive building in two different *** have used EnergyPlus modeling tool and in addition,the moni-tored ten-day indoor temperatures in two different thermal zones in the test prototype to justify the empirical validation of Building Energy *** findings demonstrate,the use of compressed earth blocks coupled with passive design strategies provides better comfort and great ***,the summer discomfort hours are reduced about 12%for both cities compared to conventional ***,the combination of semi-arid climate-responsive passive design has allowed to reach a thermal energy intensity reduction difference from 20 to 65 kWh.m^(-2).y^(-1).

关键词： Thermal comfort Energy efficiency Sustainable Compressed Earth block Passive house

Weak and strong stabilization of linear systems

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控制理论与应用（英文版） 2009年第4期7卷 359-366页

作者： Mohamed OUZAHRA Hamid BOURRAY Asmae KAMAL rachid el AYADI Departement of Mathematics and Informatics Ecole Normale Supérieure University Sidi Mohamed Ben Abdellah Fès Morocco I2R Team AFACSI Laboratory Faculty of Sciences Departement of Mathematics and Computer Sciences Moulay Ismail University Meknes Morocco

We study the problem of stabilizing a distributed linear system on a subregion of its geometrical domain. We are concerned with two methods： the first approach enables us to characterize a stabilizing control via the steady state Riccati equation, and the second one is based on decomposing the state space into two suitable subspaces and studying the projections of the initial system onto such subspaces. The obtained results are performed through various examples.

关键词： Linear systems Regional stabilization Riccati equation Decomposed method

Laminated Epoxy Biocomposites Based on Clay and Jute Fibers

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Journal of Bionic Engineering 2017年第2期14卷 379-389页

作者： Hind Abdellaoui Hala Bensalah Marya Raji Denis Rodrigue rachid Bouhfid Abou el kacem Qaiss Moroccan Foundation for Advanced Science Innovation and Research (MASclR) Institute of Nanomaterials and Nanotechnology (NANOTECIt) Laboratory of Polymer Processing Rabat Morocco Faculty of Science Laboratory of Simulation in Mechanics and Energy Mohammed V University Rabat Morocco Faculty of Science Laboratory Laboratoire de Chimieorganique et Heterocyclique Mohammed V University Rabat Morocco Department of chemical engineering and CERMA Universite Laval Quebec G1V0A6 Canada

Jute/epoxy hybrid laminated biocomposites were manufactured by using Illite clay particles at various content （5 wt.% - 20 wt.%）. The effects of hybridization on the morphology, structure, and mechanical properties were investigated. The properties of the biocomposites reinforced with jute fibers were mainly influenced by the interfacial adhesion between the jute fibers and the epoxy matrix. An alkali treatment was applied to improve the interfacial fiber-matrix adhesion and thus obtaining better mechanical properties. Besides the chemical treatment, epoxy hybridization using clay particles also had a strong effect on the overall properties of laminated biocomposites. The mechanical properties of the jute/epoxy biocomposites reinforced with Illite clay increased with clay content, up to an optimum value at 15 wt.%. The average technique and the laminates theory were performed to validate the coherence of the elastic moduli between the calculated and experimental values. A difference between the experimental and predicted data was observed, which was attributed to the simplifying assumptions made in both models. The laminates theory gave better overall predictions.

关键词： laminated biocomposites hybridization mechanical properties interracial adhesion surface treatment

Effect of Filler Content on Flexural and Viscoelastic Properties of Coir Fibers and Argania Nut-shells Reinforced Phenolic Resin Composites

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Journal of Bionic Engineering 2022年第6期19卷 1886-1898页

作者： Hala Bensalah Marya Raji Kamal Gueraoui Abdelazziz Khtira Hamid Essabir rachid Bouhfid Abou el kacem Qaiss Group of Mechanics and Materials Energy Research CenterFaculty of ScienceMohammed V University in Rabat10100RabatMorocco Composites and Nanocomposites Center Moroccan Foundation for Advanced ScienceInnovation and Research(MAScIR)10100RabatMorocco Mohammed Ⅵ Polytechnic University Lot 660 Hay Moulay Rachid43150Ben GuerirMorocco Group of Simulation in Mechanics and Energy Energy Research CenterFaculty of ScienceMohammed Ⅴ University10100RabatMorocco Group of Semiconductors and Environmental Sensor Technologies Energy Research CenterFaculty of ScienceMohammed V University10100RabatMorocco Mechanic Materials and Composites(MMC) Laboratory of Energy EngineeringMaterials and SystemsNational School of Applied Sciences of AgadirIbn Zohr University80000AgadirMorocco

The characteristics of two different kinds of lignocellulosic materials(vegetable fillers)with two morphologies as Argania nut-shells(ANS)particles and Coir Fibers(CF)were used as reinforcement for phenolic resin(Bakelite)in this work,and the composite are studied as a function of filler types,shape,content(10,20,and 30%***)and manufacturing loading force(1500 and 3000 LBs).Compression molding was used to create the composites,which were then evaluated using Scanning electronic microscopy(SEM),Fourier-transform infrared spectroscopy(FTIR),bending,dynamic-mechanical-thermal and rheological *** morphology of broken samples demonstrates that both fillers are well dispersed and *** fillers are added to the matrix,the flexural characteristics improve,and the optimal values are attained in the case of Argania *** results showed that the kind and shape of the fillers had a direct influence on the dynamic mechanical characteristics of the composites due to the reinforcement's modulus *** was noticed that,the increment of manufacturing loading force decreased the mechanical and dynamical properties of *** optimum properties obtained indicate that the composites can only be manufactured at low manufacturing loading force(1500 LBs).

关键词： Phenolic resin composites Bionic materials Coir Fibers Argania nut-shells Dynamical mechanical properties Rheological properties