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Stability analysis of a time-delayed Van der Pol–Helmholtz–Duffing oscillator in fractal space with a non-perturbative approach

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Communications in Theoretical Physics 2024年第4期76卷 22-31页

作者： Yusry O el-dib Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

The time-delayed fractal Van der Pol–Helmholtz–Duffing(VPHD)oscillator is the subject of this paper,which explores its mechanisms and highlights its stability *** time-delayed technologies are currently garnering significant attention,the focus of this research remains crucially relevant.A non-perturbative approach is employed to refine and set the stage for the system under *** innovative methodologies introduced yield an equivalent linear differential equation,mirroring the inherent nonlinearities of the ***,the incorporation of quadratic nonlinearity into the frequency formula represents a cutting-edge *** analytical solution's validity is corroborated using a numerical *** conditions are ascertained through the residual Galerkin ***,it is observed that the delay parameter,in the context of the fractal system,reverses its stabilizing influence,impacting both the amplitude of delayed velocity and the *** analytical solution's precision is underscored by its close alignment with numerical ***,the study reveals that fractal characteristics emulate damping *** its applicability across diverse nonlinear dynamical systems,this non-perturbative approach emerges as a promising avenue for future research.

关键词： Van der Pol-Helmholtz-Duffing oscillator fractal space time-delay non-perturbative approach stability analysis el-dib's frequency formula

A scalable blockchain-based scheme for traffic-related data sharing in VANETs

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Blockchain(Research and Applications) 2022年第3期3卷 109-121页

作者： el-hacen Diallo Omar dib Khaldoun Al Agha UniversitéParis-Saclay CNRSLaboratoire Interdisciplinaire des Sciences du Numérique91190Gif-sur-YvetteFrance Department of Computer Science Wenzhou-Kean UniversityWenzhou325015China

Recent advances in wireless technology and embedded systems enable vehicles to share relevant traffic-related data to improve the transportation Quality-of-Service(QoS).However,due to the ubiquitousness of cyber-attacks,it is challenging to ensure the integrity of the data collected from *** paper proposes a novel architecture for road traffic events management in Vehicular Ad hoc NETworks(VANETs)relying on a permissioned *** also introduces the concept of micro-transactions to minimize communication and storage *** simulations,a rigorous performance evaluation of the proposed approach was conducted,and the micro-transactions effectiveness was *** addition,a comparison with close works in the literature was *** proposed scheme ensures road traffic records integrity and traceability,and simulation results on the considered scenarios showed good performance.

关键词： Vehicular ad hoc NETworks(VANETs) Blockchain Consensus mechanisms Practical byzantine fault tolerance(PBFT) Data sharing

Damped Mathieu Equation with a Modulation Property of the Homotopy Perturbation Method

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Sound & Vibration 2022年第1期56卷 21-36页

作者： Yusry O.el-dib nasser S.elgazery Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

In this article,the main objective is to employ the homotopy perturbation method(HPM)as an alternative to classical perturbation methods for solving nonlinear equations having periodic *** a simple example,the nonlinear damping Mathieu equation has been *** this investigation,two nonlinear solvability conditions are *** of them was imposed in the first-order homotopy perturbation and used to study the stability behavior at resonance and non-resonance *** next level of the perturbation approaches another solvability condition and is applied to obtain the unknowns become clear in the solution for the firstorder solvability *** approach assumed here is so significant for solving many parametric nonlinear equations that arise within the engineering and nonlinear science.

关键词： Damped Mathieu Equation parametric nonlinear oscillator resonance instability homotopy perturbation method(HPM)

An innovative technique to solve a fractal damping Duffing-jerk oscillator

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Communications in Theoretical Physics 2023年第5期75卷 3-11页

作者： Yusry O el-dib nasser S elgazery Youmna M Khattab Haifa A Alyousef Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Physics College of SciencePrincess Nourah bint Abdulrahman UniversityPO Box 84428Riyadh 11671Saudi Arabia

The idea of the present article is to look into the nonlinear dynamics and vibration of a damping Duffing-jerk oscillator in fractal space exhibiting the non-perturbative *** a new analytical technique,namely,the modification of a He’s fractal derivative that converts the fractal derivative to the traditional derivative in continuous space,this study provides an effective and easy-to-apply procedure that is dependent on the He’s fractal derivative *** analytic approximate solution has a significant match with the results of the numerical simulation as the fractal parameter is very closer to unity,which proves the reliability of the *** behavior is discussed and illustrated *** new powerful analytical tools are developed in an attempt to obtain effective analytical tools,valid for any fractal nonlinear problems.

关键词： modification of He’s fractal derivative fractal duffing-jerk vibration stability analysis non-perturbative approach damping nonlinear fractal system

Hypoglycaemic effect of Berberis vulgaris *** normal and streptozotocin-induced diabetic rats

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Asian Pacific Journal of Tropical Biomedicine 2011年第6期1卷 468-471页

作者： nawel Meliani Mohamed el Amine dib Hocine Allali Boufeldja Tabti Laboraloire des Substances naturelles et Bioactives (LASnaBIO) Departement de Chimie Faculte des SciencesUniversite Aboubekr Belkaid BP 119

Objective:To achieve a primary pharmacological screening contained in the aqueous extract of Berberis vulgaris(***) and to examine the hypoglycaemic effect and biochemical parameters of aqueous and saponins extract on groups of rats rendered diabetic by injection of ***:The phytochemicol tests to detect the presence of different compounds were based on the visual observation of color change or formation of precipitate after the addition of specific *** was induced in rats by intraperitoneal(i.p.) injection of streptozotocin(STZ) at a dose of 65 mg/kg *** fasting blood glucose levels were estimated by glucose oxidase-peroxidase reactive strips(Dextrostix,Bayer Diagnostics).Blood samples were taken by cutting the tip of the *** cholesterol and serum triglycerides were estimated by enzymatic DHBS colorimetric ***:Administration of 62.5 and 2S.0 mg/kg of saponins and aqueous extract respectively in normal rats group shows a significant hypoglycemic activity(32.33%and 40.17%respectively) during the first ***,diabetic group treated with saponin extract produced a maximum fall of 73.1%and 76.03%at day 1 and day 21 compared to the diabetics ***,blood glucose levels of the diabetic rats treated with aqueous extract showed decrease of 78.79%on the first day and the effect remains roughly constant during 3 week. Both extracts also declined significantly biochemical parameters(20.77%-49.00%).The control in the loss of body weight was observed in treated diabetic rats as compared to diabetic controls. Conclusions:These results demonstrated significant antidiabetic effects and showed that serum cholesterol and serum triglycerides levels were decreased,significantly,consequently this plant might be of value in diabetes treatment.

关键词： Berberis vulgaris L. Antidiabetic activity Streptozotocin-induced diabetes Saponins Aqueous extract Photochemical screening Hypoglycaemic effect Biochemical parameters Cholesterol Triglycerides Glucose oxidase-peroxidase Colorimetric method

Disruption of biofilms from sewage pipes under physical and chemical conditioning

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Journal of Environmental Sciences 2009年第1期21卷 120-126页

作者： Charbel Mahfoud Antoine el Samrani Rita Mouawad Walid Hleihel Rim el Khatib Bruno S. Lartiges nam Ouani Holy Spirit University of Kaslik(USEK) Faculty of Sciences and Computer Engineering Department of Chemistry and Life SciencesWater and Environment Laboratory. P.B. 446JouniehLebanon nancy University LEM-ENSG/INPL-CNRSPole de l'Eau15Avenue du CharmoisBP 40-F-54501 Vandoeuvre CedexFrance

Biofilms grown inside two sewage collecting pipes located in industrial and residential areas are studied. Bacterial biomass inside three layers of biofilms was evaluated. Biofilm cohesion under different mixing rate and ionic strength was also investigated. Effects of physical and chemical parameters in the biofilms were evaluated by monitoring turbidity, chemical and biochemical oxygen demands. Extracted organic matter from biofilms was partitioned to polar, aromatic and saturated fractions using activated silica column chromatography. Results revealed that bacterial biomass growth depending on biofilm thickness and stratification. The most loaded stratum in bacteria/biomass was the sewage-biofilm interface stratum that represented 51% of the total bacteria/biomass. Stirring rate and ionic strength of mono- and bivalent salts showed a major influence in biofilm disruption. The stirring time enhanced the exchange dynamic and matter capture between biofilm fragments at the critical stirring rate 90 r/min. Sodium chloride showed the dispersing effect on biofilms in suspension, and decreased the BOD5 （biochemical oxygen demand） beyond the physiological salt concentration.

关键词： biofilms, biochemical oxygen demand (BODs) chemical oxygen demand (COD) biomass ionic strength

ASYMPTOTIC BEHAVIOR OF THE TE AND TM APPROXIMATIONS TO SECOND HARMONIC GENERATION

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Journal of Computational Mathematics 2007年第1期25卷 49-66页

作者： na■ma A■ssa Faculté de Mathématiques USTHBBP32El AliaBab Ezzouar16111Alger Centre de Mathématiques Appliquées CNRS UMR 7641■Ecole PolytechniquePalaiseau 91128 CedexFrance

We consider a Second Harmonic Generation （SHG） problem of an optical signal wave with an optical pump in a medium represented by a smooth bounded domain Ω→∩ IR^d which is assumed to contain a heterogeneous material： a compactly imbedded subdomain B^r →∩∩ in the shape of a small ball contains a nonlinear material, while Ω／ B^r is filled with a linear material. We begin by proving existence and uniqueness of the solution to the TE approximation of SHG for arbitrary bounded susceptibilities, thus improving the result obtained by Bao and Dobson （ Eur. J. Appl. Math. 6 （1995）, 573-590） under small enough susceptibilities assuption. We then establish an existence and uniqueness result of a solution to the TM approximation problem. In both parts we study the asymptotic behavior of the system as the size of the nonlinear material vanishes： error estimates and asymptotic expansion of the solution are derived for both TE and TM approximations.

关键词： Second harmonic generation TE Approximation TM Approximation.

Geochemical assessment, mixing behavior and environmental impact of thermal waters in the Guelma geothermal system,Algeria

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Acta Geochimica 2019年第5期38卷 683-702页

作者： Foued Bouaicha Henia dib Oualid Bouteraa nabil Manchar Kamel Boufaa nabil Chabour Abdeslam Demdoum Department of Applied Biology Universite des Freres Mentouri Constantine 1025000 ConstantineAlgeria Department of Geology Universite des Freres Mentouri Constantine 1025000 ConstantineAlgeria Laboratory of Geology and Environment (LGE) Uni versite des Freres Mentouri Constantine 1ConstantineAlgeria Department of Geology Sciences University of Larbi Ben M'hidi04000 Oum El BouaghiAlgeria Department of Earth Sciences University of Setif 119000 SetifAlgeria

A study of thirteen geothermal springs located in the geothermal field of Guelma,northeastern Algeria,was *** were collected during the period between January 2014 and February *** processes responsible for the chemical composition of thermal and mineralized water were *** hydrochemical analysis shows that the thermal waters are characterized by the presence of two different chemical facies,the first type SO4-Ca in the east,west and south of Guelma,the second type HCO3-Ca in the *** analysis also attributed to sodium,chlorides,and sulfates to an evaporitic terrigenous origin by the molar ratio Sr2+/Ca2+.The thermal spring waters from Guelma geothermal system have a meteoric origin,and all samples are immature with strong mixing between hot and shallow waters with 19-38.5%rate of *** silica geothermometer shows that these thermal waters have a temperature varying from 84 to 122℃and that the water came from a depth of 2100-3000 m through a fault system that limits the pullapart basin of *** environmental effluent from thermal spas could pollute in both the irrigation and drinking waters,and which imposes danger on the health of the inhabitants of the region.

关键词： Geochemistry Geothermometry Mixing Thermal effluents Guelma Algeria

Temporal pattern of resolution/recurrence of choroidal neovascularization during bevacizumab therapy for wet age-related macular degeneration

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International Journal of Ophthalmology(English edition) 2013年第5期6卷 600-605页

作者： Haiyan Wang Giulio Barteselli William R.Freeman Su na Lee Jay Chhablani Sharif el-Emam Lingyun Cheng Department of Ophthalmology Jacobs Retina Center at Shiley Eye CenterUniversity of California San Diego

AIMTo characterize temporal pattern of resolution and recurrence of naive choroidal neovascularization (CNV) secondary to wet age-related macular degeneration (AMD) treated with intravitreal bevacizumab on as needed r... 详细信息

关键词： bevacizumab age-related macular degeneration recurrence anti-vascular endothelial growth factor therapy