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Analysis and Numerical Approximation of an electro-elastic Frictional Contact Problem

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Advances in Applied Mathematics and Mechanics 2010年第3期2卷 355-378页

作者： el-h.essoufi el-h.Benkhira R.Fakhar Universitéhassan I Facultédes Sciences et Téchniques Département de Mathématiques et Informatique B.P.577SettatRoute de CasablancaSettatMaroc

We consider a mathematical model which describes the static frictional contact between a piezoelectric body and a conductive foundation.A non linear electro-elastic constitutive law is used to model the piezoelectric *** unilateral contact is modelled using the Signorini condition,nonlocal Coulomb friction law with slip dependent friction coefficient and a regularized electrical conductivity *** and uniqueness of a weak solution is established.A finite elements approximation of the problem is presented,a priori error estimates of the solutions are derived and a convergent successive iteration technique is proposed.

关键词： electro-elastic static problem piezoelectric materials unilateral contact nonlocal Coulomb’s friction variational inequality fixed point finite element approximation iterative method error estimates

A Synergistic Multi-Attribute Decision-Making Method for Educational Institutions Evaluation Using Similarity Measures of Possibility Pythagorean Fuzzy hypersoft Sets

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 501-530页

作者： Khuram Ali Khan Saba Mubeen Ishfaq Atiqe Ur Rahman Salwa el-Morsy Department of Mathematics University of SargodhaSargodha40100Pakistan Department of Mathematics University of Management and TechnologyLahore54000Pakistan Department of Mathematics College of ScienceQassim UniversityBuraydah51452Saudi Arabia

Due to the numerous variables to take into account as well as the inherent ambiguity and uncertainty,evaluating educational institutions can be *** concept of a possibility Pythagorean fuzzy hypersoft set(pPyFhSS)is more flexible in this regard than other theoretical fuzzy set-like models,even though some attempts have been made in the literature to address such *** study investigates the elementary notions of pPyFhSS including its set-theoretic operations union,intersection,complement,OR-and *** results related to these operations are also modified for ***,the similarity measures between pPyFhSSs are formulated with the assistance of numerical examples and ***,an intelligent decision-assisted mechanism is developed with the proposal of a robust algorithm based on similarity measures for solving multi-attribute decision-making(MADM)problems.A case study that helps the decision-makers assess the best educational institution is discussed to validate the suggested *** algorithmic results are compared with the most pertinent model to evaluate the adaptability of pPyFhSS,as it generalizes the classical possibility fuzzy set-like theoretical ***,while considering significant evaluating factors,the flexibility of pPyFhSS is observed through structural comparison.

关键词： hypersoft set Pythagorean fuzzy hypersoft set computational complexity multi-attribute decision-making optimization similarity measures uncertainty

Comparative study of semiconductor power losses between CSI-based STATCOM and VSI-based STATCOM,both used for unbalance compensation

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Protection and Control of Modern Power Systems 2020年第1期5卷 56-69页

作者： Anas Benslimane Jamal Bouchnaif Mohammed essoufi Bekkay hajji Loukmane el Idrissi Laboratory Renewable energy embedded system and information processingNational School of Applied SciencesUniversity of Mohammed IOujdaMorocco Laboratory of electrical Engineering and Maintenance Higher School of TechnologyUniversity of Mohammed IOujdaMorocco

In this paper,we present a detailed procedure to determine the semiconductor losses for both structures of a shunt STATCOM(Static Compensator),STATCOM based on Current Source Inverter(CSI)and STATCOM based on Voltage Source Inverter(VSI),both used for voltage unbalance *** a first step,we study the VSI-based STATCOM and the CSI-based STATCOM used in high speed railway *** we analyze the design and the sizing of the unbalance compensator in order to obtain an unbalance factor that does not exceed the limits imposed by the standards or by the energy *** that,we compare the performances obtained with both structures VSI-STATCOM and CSI-STATCOM,after calculating the semiconductor power losses in the STATCOM ***,we validate our approach by simulation over real data of unbalance compensation caused by the new high-speed railway in *** use the tools MATLAB/Simulink/Simpowersys for performing our simulations.

关键词： Power losses VSI CSI STATCOM Unbalance compensation Railway

Solid Waste Management:A MADM Approach Using Fuzzy Parameterized Possibility Single-Valued Neutrosophic hypersoft Expert Settings

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 531-553页

作者： Tmader Alballa Muhammad Ihsan Atiqe Ur Rahman Noorah Ayed Alsorayea hamiden Abd el-Wahed Khalifa Department of Mathematics College of SciencesPrincess Nourah bint Abdulrahman UniversityRiyadh11671Saudi Arabia 2 Department of Mathematics University of Management and TechnologyLahore54000Pakistan Department of Mathematics College of ScienceQassim UniversityBuraydah51452Saudi Arabia

The dramatic rise in the number of people living in cities has made many environmental and social problems *** search for a productive method for disposing of solid waste is the most notable of these *** scholars have referred to it as a fuzzy multi-attribute or multi-criteria decision-making problem using various fuzzy set-like approaches because of the inclusion of criteria and anticipated *** goal of the current study is to use an innovative methodology to address the expected uncertainties in the problem of solid waste site *** characteristics(or sub-attributes)that decision-makers select and the degree of approximation they accept for various options can both be indicators of these *** tackle these problems,a novel mathematical structure known as the fuzzy parameterized possibility single valued neutrosophic hypersoft expert set(ρˆ-set),which is initially described,is integrated with a modified version of Sanchez’s *** this,an intelligent algorithm is *** steps of the suggested algorithm are explained with an example that explains *** compatibility of solid waste management sites and systems is discussed,and rankings are established along with detailed justifications for their *** study’s strengths lie in its application of fuzzy parameterization and possibility grading to effectively handle the uncertainties embodied in the parameters’nature and alternative approximations,*** uses specific mathematical formulations to compute the fuzzy parameterized degrees and possibility grades that are missing from the prior *** is simpler for the decisionmakers to look at each option separately because the decision is *** the computed results,it is discovered that they are consistent and dependable because of their preferred properties.

关键词： hypersoft expert set Sanchez’s method decision making optimization solid waste management possibility grade fuzzy parameterization

Effect of high-Frequency electric Field on Propagation of electrostatic Wave in a Non-Uniform Relativistic Plasma Waveguide

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Plasma Science and Technology 2008年第3期10卷 278-283页

作者： Kh.h.el-ShORBAGY Plasma Physics and Nuclear Fusion Department Nuclear Research Center Atomic Energy Authority Cairo Egypt

The effect of a high frequency （hF） electric field on the propagation of electrostatic wave in a 2D non-uniform relativistic plasma waveguide is investigated. A variable separation method is applied to the two-fluid plasma model. An analytical study of the reflection of electrostatic wave propagation along a magnetized non-uniform relativistic plasma slab subjected to an intense hF electric field is presented and compared with the case of a non relativistic plasma. It is found that, when the frequency of the incident wave is close to the relativistic electron plasma frequency, the plasma is less reflective due to the presence of both an hF field and the effect of relativistic electrons. On the other hand, for a low-frequency incident wave the reflection coefficient is directly proportional to the amplitude of the hF field. Also, it is shown that the relativistic electron plasma leads to a decrease in the value of reflection coefficient in comparison with the case of the non relativistic plasma.

关键词： electrostatic wave relativistic plasma waveguide reflection coefficient separation method

electrical properties of ^(70)Ge:Ga near the metal–insulator transition

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Journal of Semiconductors 2015年第6期36卷 1-5页

作者： M Errai A el kaaouachi h el idrissi Laboratoire MSTI Ecole Supérieure de tecchnologie d'Agadir B.P: 33/S University Ibn ZohrFaculty of Sciences AgadirMorocco Laboratoire electronique électrotechnique Automatique et Traitement de l'Information Département Génie Electrique Faculté des Sciences et Techniques de Mohammedia Université Hassan II Mohammedia CasablancaBP 146 Quartier YasminaMohammedia

The results of the metal-insulator transition （MIT） induced by impurity concentration are presented in the case of metallic and insulating samples 70Ge：Ga p-type. The eight samples studied have Ga concentrations N ranging from 1.848 × 1017 to 1.912 × 10^17 cm-3. The conductivity measurements were carried out at low temperature in the range 1 to 0.019 K. We provide physical explanations to explain the behaviors of the temperature dependence of the electrical conductivity in both sides of the MIT. The data are for a 70Ge：Ga sample prepared and reported by Itoh et aL in Ref. [Itoh K M, Watanabe M, Ootuka Y, et al. J Phys Soc Jpn, 2004, 73（1）： 173].

关键词： 70Ge: Ga semiconductor low temperature impurity concentration metal-insulator variable rangehopping conductivity transport properties

Variable range hopping conduction in n-CdSe samples at very low temperature

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Journal of Semiconductors 2015年第12期36卷 14-17页

作者： M Errai A el Kaaouachi h el Idrissi Physics Department Ibn Zohr University Faculty of Sciences Laboratoire electronique électrotechnique Automatique et Traitement de l'Information Département Génie ElectriqueFaculté des Sciences et Techniques de Mohammedia Université Hassan Ⅱ Mohammedia Casablanca

We reanalyzed experimental data already published in Friedman J R, Zhang Y, Dai P, et al. Phys Rev B, 1996, 53（15）： 9528. Variable range hopping （VRh） conduction in the insulating three-dimensional n-CdSe samples has been studied over the entire temperature range from 0.03 to 1 K. In the absence of a magnetic field, the low temperature conductivity a of the three samples （A, B and C） obeys the Mott VRh conduction with an appropriate temperature dependence in the prefactor （a = σ0 exp [- （T0/T）]^p with p ≈ 0.25）. This behavior can be explained by a VRh model where the transport occurs by hopping between localized states in the vicinity of the Fermi level, EF, without creation of the Coulomb gap （CG）. On the contrary, no Efros-Shklovskii VRh is observed, suggesting that the density is constant in the vicinity of the EF.

关键词： n-CdSe samples low temperature variable range hopping density of state

Summary of the current guidelines for managing iatrogenic colorectal perforations and the evolving role of endoluminal vacuum therapy

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World Journal of Clinical Cases 2025年第6期13卷 1-8页

作者： Ahmed Tawheed Ibrahim halil Bahcecioglu Mehmet Yalniz Mubin Ozercan Ali Cagri Oral Mohamed el-Kassas Department of Endemic Medicine Faculty of MedicineHelwan UniversityCairo 11795Egypt Department of Gastroenterology Firat UniversityElazig 23119Türkiye Liver Disease Research Center College of MedicineKing Saud UniversityRiyadh 7805Saudi Arabia

Colonoscopy represents a safe procedure that is widely used in medical practice either to diagnose or treat various gastrointestinal *** the last few years,the incidence rate of perforations in colonoscopic procedures has increased,especially in therapeutic *** recent advancements in endoscopic techniques and gastrointestinal tumoral resection procedures such as endoscopic mucosal resection,endoscopic full-thickness resection,and endoscopic submucosal dissection(ESD)could be a risk factor for this increased *** incidence rate of mortality of serious colonoscopic perforations is 7.1%.The management plan for these perforations starts with conservative treatment in mild cases,endoscopic closure,and surgical management in severe ***,endoluminal vacuum therapy was found to be effective in the management of colorectal perforations and this has been reported in multiple case *** editorial provides an overview of the current guidelines for the management of iatrogenic colorectal *** insights are from the perspectives of endoscopists and *** also present a management algorithm based on the guidelines of the European Society of Gastrointestinal Endoscopy,the American Gastroenterological Association,and the World Society of Emergency *** also discussed in brief the use of endoluminal vacuum therapy in colorectal perforations.

关键词： Colon Rectum Iatrogenic colonic perforation Colonoscopy Guidelines Endovacuum Endolumical vacuum therapy Endoscopic management

Effect of substitution group on dielectric properties of 4h-pyrano [3,2-c] quinoline derivatives thin films

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Chinese Physics B 2016年第7期25卷 440-449页

作者： h M Zeyada F M el-Taweel M M el-Nahass M M el-Shabaan Department of Physics Faculty of Science Damietta University Department of Chemistry Faculty of Science Damietta University Department of Physics Faculty of Education Ain Shams University

The AC electrical conductivity and dielectrical properties of 2-amino-6-ethyl-5-oxo-4-（3-phenoxyphenyl）-5,6-dihydro-4h-pyrano[3, 2-c]quinoline-3-carbonitrile（Ph-hPQ） and 2-amino-4-（2-chlorophenyl）-6-ethyl-5-oxo-5,6-dihydro-4h-pyrano [3, 2-c] quinoline-3-carbonitrile（Ch-hPQ） thin films were determined in the frequency range of 0.5 k hz–5 Mhz and the temperature range of 290–443 K. The AC electrical conduction of both compounds in thin film form is governed by the correlated barrier hopping（CBh） mechanism. Some parameters such as the barrier height, the maximum barrier height, the density of charges, and the hopping distance were determined as functions of temperature and frequency. The phenoxyphenyl group has a greater influence on those parameters than the chlorophenyl group. The AC activation energies were determined at different frequencies and temperatures. The dielectric behaviors of Ph-hPQ and Ch-hPQ were investigated using the impedance spectroscopy technique. The impedance data are presented in Nyquist diagrams for different temperatures. The Ch-hPQ films have higher impedance than the Ph-hPQ films. The real dielectric constant and dielectric loss show a remarkable dependence on the frequency and temperature. The Ph-hPQ has higher dielectric constants than the Ch-hPQ.

关键词： thin films quinoline derivatives dielectrical properties correlated barrier hopping