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High-Order Spatial f.TD Solver of.Maxwell’s Equations f.r Terahertz Radiation Production

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Journal of.Applied Mathematics and Physics 2024年第4期12卷 1028-1042页

作者： Abdelrahman mahdy Department of.Physical Sciences College of Science Jazan University Jazan Kingdom of Saudi Arabia

We applied a spatial high-order f.nite-dif.erence-time-domain (HO-f.TD) scheme to solve 2D Maxwell’s equations in order to develop a f.uid model employed to study the production of.terahertz radiation by the f.lamentation of.two f.mtosecond lasers in air plasma. We examined the perf.rmance of.the applied scheme, in this context, we implemented the developed model to study selected phenomena in terahertz radiation production, such as the excitation energy and conversion ef.iciency of.the produced THz radiation, in addition to the inf.uence of.the pulse chirping on properties of.the produced radiation. The obtained numerical results have clarif.ed that the applied HO-f.TD scheme is precisely accurate to solve Maxwell’s equations and suf.iciently valid to study the production of.terahertz radiation by the f.lamentation of.two f.mtosecond lasers in air plasma.

关键词： The f.nite-Dif.erence-Time-Domain Terahertz Radiation Production f.lamentation of.f.mtosecond Laser Maxwell’s Equations Solution

Magneto-Photo-Thermoelastic Excitation Rotating Semiconductor Medium Based on Moisture Dif.usivity

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Computer Modeling in Engineering & Sciences 2024年第10期141卷 107-126页

作者： Khaled Lotf. A.M.S.mahdy Alaa A.El-Bary E.S.Elidy Department of.Mathematics Faculty of ScienceZagazig UniversityZagazig44519Egypt Department of.Mathematics Faculty of ScienceTaibah UniversityMadinah42353Saudi Arabia Department of.Mathematics and Statistics College of ScienceTaif UniversityTaif11099Saudi Arabia Arab Academy f.r Science Technology and Maritime TransportAlexandria1029Egypt

In this research,we f.cus on the f.ee-surf.ce def.rmation of.a one-dimensional elastic semiconductor medium as a f.nction of.magnetic f.eld and moisture *** problem aims to analyze the interconnection between plasma and moisture dif.usivity processes,as well as thermo-elastic *** study examines the photothermoelasticity transport process while considering the impact of.moisture *** employing Laplace’s transf.rmation technique,we derive the governing equations of.the photo-thermo-elastic *** equations include the equations f.r carrier density,elastic waves,moisture transport,heat conduction,and constitutive *** stresses,thermal conditions,and plasma boundary conditions are used to calculate the f.ndamental physical parameters in the Laplace *** employing numerical techniques,the Laplace transf.rm is inverted to get complete time-domain solutions f.r the primary physical domains under ***,thermoelastic,and thermoelectric characteristics are employed in conjunction with a graphical analysis that takes into consideration the ef.ects of.applied f.rces on displacement,moisture concentration,carrier density,stress due to f.rces,and temperature distribution.

关键词： Moisture dif.usivity semiconductor photothermoelastic rotation thermomechanical waves laplace transf.rm

Advancing Early Detection of.Colorectal Adenomatous Polyps via Genetic Data Analysis: A Hybrid Machine Learning Approach

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Journal of.Computer and Communications 2024年第7期12卷 23-38页

作者： Ahmed S. Maklad Mohamed A. mahdy Amer Malki Noboru Niki Abdallah A. Mohamed Computer Science Department College of Computer Science and Engineering in Yanbu Taibah University Medina Saudi Arabia Inf.rmation Systems Department Faculty of Computers and Artificial Intelligence Beni-Suef University Beni-Suif Egypt Computer Science Department Faculty of Computers and Artificial Intelligence Beni-Suef University Beni-Suif Egypt Institute of.Advanced Science and Technology Tokushima University Tokushima Japan Inf.rmation Systems Department College of Computer Science and Engineering in Yanbu Taibah University Medina Saudi Arabia Mathematics and Computer Science Department Faculty of Science Menoufia University Menoufia Egypt

In this study, a hybrid machine learning (HML)-based approach, incorporating Genetic data analysis (GDA), is proposed to accurately identif. the presence of.adenomatous colorectal polyps (ACRP) which is a crucial early detector of.colorectal cancer (CRC). The present study develops a classif.cation ensemble model based on tuned hyperparameters. Surpassing accuracy percentages of.early detection approaches used in previous studies, the current method exhibits exceptional perf.rmance in identif.ing ACRP and diagnosing CRC, overcoming limitations of.CRC traditional methods that are based on error-prone manual examination. Particularly, the method demonstrates the f.llowing CRP identif.cation accuracy data: 97.7 ± 1.1, precision: 94.3 ± 5, recall: 96.0 ± 3, f.-score: 95.7 ± 4, specif.city: 97.3 ± 1.2, average AUC: 0.97.3 ± 0.02, and average p-value: 0.0425 ± 0.07. The f.ndings underscore the potential of.this method f.r early detection of.ACRP as well as clinical use in the development of.CRC treatment planning strategies. The advantages of.this approach are highly expected to contribute to the prevention and reduction of.CRC mortality.

关键词： Colorectal Adenoma Detection Colorectal Cancer Diagnosis Hybrid Machine Learning Genetics Analysis

Simultaneous impacts of.MHD and variable wall temperature on transient mixed Casson nanof.uid f.ow in the stagnation point of.rotating sphere

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Applied Mathematics and Mechanics(English Edition) 2018年第9期39卷 1327-1340页

作者： A.mahdy Department of.Mathematics Faculty of Science South Valley University

A numerical analysis is provided to scrutinize time-dependent magnetohydrodynamics(MHD) f.ee and f.rced convection of.an electrically conducting non-Newtonian Casson nanof.uid f.ow in the f.rward stagnation point region of.an impulsively rotating sphere with variable wall temperature. A single-phase f.ow of.nanof.uid model is ref.ected with a number of.experimental f.rmulae f.r both ef.ective viscosity and thermal conductivity of.nanof.uid. Exceedingly nonlinear governing partial dif.erential equations(PDEs)subject to their compatible boundary conditions are mutated into a system of.nonlinear ordinary dif.erential equations(ODEs). The derived nonlinear system is solved numerically with implementation of.an implicit f.nite dif.erence procedure merging with a technique of.quasi-linearization. The controlled parameter impacts are clarif.ed by a parametric study of.the entire f.ow regime. It is depicted that f.om all the exhibited nanoparticles,Cu possesses the best convection. The surf.ce heat transf.r and surf.ce shear stresses in the x-and z-directions are boosted with maximizing the values of.nanoparticle solid volume f.action ? and rotation λ. Besides, as both the surf.ce temperature exponent n and the Casson parameter γ upgrade, an enhancement of.the Nusselt number is given.

关键词： single-phase nanof.uid Casson transient mixed magnetohydrodynamics(MHD) non-unif.rm heating

Soil Properties and Wheat Growth and Nutrients as Af.ected by Compost Amendment Under Saline Water Irrigation

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Pedosphere 2011年第6期21卷 773-781页

作者： A.M.mahdy Department of.Soil and Water College of Agriculture(Elshatby)Alexandria University

A greenhouse experiment was conducted to test and compare the suitability of.saline compost and saline irrigation water f.r nutrient status amendment of.a slightly productive sandy clay loam soil, to study the macronutrient utilization and dry matter production of.wheat （Triticum aestivum c.v. Gemmiza 7） grown in a modif.ed soil environment and to determine the ef.ects of.compost and saline irrigation water on soil productivity. The sandy clay loam soil was treated with compost of.f.ve rates （0, 24, 36, 48, and 60 m3 ha-1, equivalent to 0, 3, 4.5, and 6 g kg-1 soil, respectively） and irrigation water of.f.ur salinity levels （0.50 （tap water）, 4.9, 6.3, and 8.7 dS m-l）. The results indicated that at harvest, the electrical conductivity （EC） of.the soil was signif.cantly （P 〈 0.05） changed by the compost application as compared to the control. In general, the soil salinity signif.cantly increased with increasing application rates of.compost. Soluble salts, K, C1, HCO3, Na, Ca, and Mg, were signif.cantly increased by the compost treatment. Soil sodium adsorption ratio （SAR） was signif.cantly af.ected by the salinity levels of.the irrigation water, and showed a slight response to the compost application. The soil organic carbon content was also signif.cantly （P 〈 0.05） af.ected by application of.compost, with a maximum value of.31.03 g kg-1 recorded at the compost rate of.60 m3 ha-1 and the irrigation water salinity level of.8.7 dS m-1 and a minimum value of.12.05 g kg-1 observed in the control. The compost application produced remarkable increases in wheat shoot dry matter production. The maximum dry matter production （75.11 g pot-1） occurred with 60 ma ha-1 compost and normal irrigation water, with a minimum of.19.83 g pot-1 with no addition of.compost and irrigation water at a salinity level of.8.70 dS m-1. Signif.cant increases in wheat shoot contents of.K, N, P, Na, and C1 were observed with addition of.compost. The relatively high shoot N values may be attributed

关键词： electrical conductivity plant dry matter soil organic C soil sodium adsorption ratio soluble salts

Laminar MHD natural convection of.nanof.uid containing gyrotactic microorganisms over vertical wavy surf.ce saturated non-Darcian porous media

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Applied Mathematics and Mechanics(English Edition) 2016年第4期37卷 471-484页

作者： S.E.AHMED A.mahdy Department of.Mathematics Faculty of Sciences South Valley University

Magnetohydrodynamic （MHD） bioconvection of.an incompressible electrically conducting nanof.uid near a vertical wavy surf.ce saturated porous medium containing both nanoparticle and gyrotactic microorganisms is investigated. The nanof.uid is represented by a model that includes both Brownian motion and thermophoresis ef.ects. A suitable set of.non-dimensional variables are used to transf.rm the governing boundary layer equations into a dimensionless f.rm. The resulting nonlinear system is mapped to the vertical f.at plate domain, and a non-similar solution is used to the obtained equations. The obtained non-similar system is then solved numerically using the f.urth-order Runge-Kutta method. The inf.uence of.various physical parameters on the local Nusselt number, the local Sherwood number, the local density number of.the motile microorganisms, the dimensionless velocity, the dimensionless temperature, and the rescaled density of.motile microorganisms is studied. It is f.und that the local Nusselt number, the local Sherwood number, and the local density number of.the motile microorganisms decrease by increasing either the Grashof.number or the magnetic f.eld parameter.

关键词： wavy surf.ce nanof.uid non-Darcy bioconvection boundary layer gyrotactic microorganism porous media

Macroscopic Studies on the Properties of.the Anodic Oxide f.lms on Titanium

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Journal of.Materials Science & Technology 1998年第3期14卷 241-246页

作者： mahdy, G.A. Mahmoud, S.S. Chemistry Dept. Faculty of Science Helwan University Helwan Cairo Egypt Chemistry Dept. University College for Women Ain-Shams University Helopolis Cairo Egypt

The ef.ect of.f.uoride ions on the f.rmation and dissolution behaviour of.anodic oxide f.lms on Ti has been investigated in acidic f.uoride media (pH=1) using impedance and galvanostatic techniques. A5 the f.uoride ion concentration and temperature increase the rate of.oxide f.lm f.rmation decreases while the dissolution process increases. oxide f.lm f.rmed at high tem-perature and f.rmation voltage was f.und to contain more def.ct sites in the f.lm than that f.rmed at a lower one. Activation energies are calculated during the oxide f.lm f.rmation and dissolution and f.und to be 20.76 and 28.72 kJ/mol, respectively. f.rmation rate and reciprocal capacitance data are reported as a f.nction of.polarizing current density. Values are recorded f.r the electrolytic parameters A and B. Potentiostatic curves are derived f.om the galvanostatic results.

关键词： f.gure Macroscopic Studies on the Properties of.the Anodic Oxide f.lms on Titanium

Numerical studies f.r solving f.actional integro-dif.erential equations

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Journal of.Ocean Engineering and Science 2018年第2期3卷 127-132页

作者： A.M.S.mahdy Department of.Mathematics Faculty of ScienceZagazig UniversityZagazigEgypt Department of.Mathematics Faculty of ScienceTaif UniversitySaudi Arabia

In this paper,we give a new numerical method f.r solving a linear system of.f.actional integro-dif.erential *** f.actional derivative is considered in the Caputo *** proposed method is least squares method aid of.Hermite *** suggested method reduces this type of.systems to the solution of.systems of.linear algebraic *** demonstrate the accuracy and applicability of.the presented method some test examples are *** results show that this approach is easy to implement and accurate when applied to integro-dif.erential *** show that the solutions approach to classical solutions as the order of.the f.actional derivatives approach.

关键词： Least squares method Caputo f.actional Hermite polynomials Linear f.actional integro-dif.erential equations

Using Syntactic-Based Kernels f.r Classif.ing Temporal Relations

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Journal of.Computer Science & Technology 2011年第1期26卷 68-80页

作者： Seyed Abolghasem Mirroshandel Gholamreza Ghassem-Sani mahdy Khayyamian Department of.Computer Engineering Sharif University of Technology

Temporal relation classif.cation is one of.contemporary demanding tasks of.natural language processing. This task can be used in various applications such as question answering, summarization, and language specif.c inf.rmation retrieval. In this paper, we propose an improved algorithm f.r classif.ing temporal relations, between events or between events and time, using support vector machines （SVM）. Along with gold-standard corpus f.atures, the proposed method aims at exploiting some usef.l automatically generated syntactic f.atures to improve the accuracy of.classif.cation. Accordingly, a number of.novel kernel f.nctions are introduced and evaluated. Our evaluations clearly demonstrate that adding syntactic f.atures results in a considerable improvement over the state-of.the-art method of.classif.ing temporal relations.

关键词： temporal relation classif.cation inf.rmation retrieval text mining support vector machines kernel f.nction