检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Design of.multi-antenna relaying f.r Of.M in impulsive noise environment

在线全文

学校读者我要写书评

暂无评论

Digital Communications and Networks 2019年第3期5卷 189-195页

作者： Ahmed El-mahdy MennaTullah Seraj-Eldin Prof.ssor in the f.culty of.Inf.rmation Engineering and Technology German University in Cairo Cairo Egypt The f.culty of.Inf.rmation Engineering and Technology German University in Cairo Cairo Egypt

A low-complexity multi-antenna relaying scheme is proposed f.r Orthogonal f.equency Division Multiplexing (Of.M) in the presence of.Class-A Impulsive Noise (IN). One way and two way relaying are considered. The signal is transmitted and received by two terminal nodes, each with a single antenna in two time phases. In the proposed design, the processing at the relay consists of.Maximal-Ratio Combining (MRC) or Power-based Selection Combining (PSC) f.r receive combining, Amplif. and f.rward (Af. f.r power scaling, and Space Time Block Coding (STBC) f.r transmit diversity. Channel State Inf.rmation (CSI), Discrete f.urier Transf.rm (Df.), and Inverse Discrete f.urier Transf.rm (IDf.) are not needed. The Selective Mapping (SLM) technique is used at the transmitter to reduce the Peak-to-Average Power Ratio (PAPR) of.the Of.M signal. Then, at the receiver, the clipping technique is used to reduce the impulses that result f.om the impulsive noise. The proposed system reduces the complexity of.the conventional system, which uses multi-relay with a single antenna. Simulation results show that the Bit Error Rate (BER) of.the proposed scheme outperf.rms that of.the conventional scheme due to the diversity inherent in the proposed scheme.

关键词： Orthogonal f.equency division multiplexing Impulsive noise Multi-antenna relay Reception combining Transmit diversity Peak-to-average power ratio reduction techniques

Optimal and Memristor-Based Control of.A Nonlinear f.actional Tumor-Immune Model

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第6期67卷 3463-3486页

作者： Amr M.S.mahdy Mahmoud Higazy Mohamed S.Mohamed Department of.Mathematics College of ScienceTaif UniversityTaif21944Saudi Arabia Department of.Mathematics Faculty of ScienceZagazig UniversityZagazig44519Egypt Department of.Physics and Engineering Mathematics Faculty of Electronic engineeringMenoufia UniversityMenouf32952Egypt Department of.Mathematics Faculty of ScienceAl-Azher UniversityNasr City11884Egypt

In this article,the reduced dif.erential transf.rm method is introduced to solve the nonlinear f.actional model of.*** f.actional derivatives are described in the Caputo *** solutions derived using this method are easy and very *** model is given by its signal f.ow ***,a simulation of.the system by the Simulink of.MATLAB is *** disease-f.ee equilibrium and stability of.the equilibrium point are *** of.a f.actional optimal control f.r the cancer model is *** addition,to control the system,we propose a novel modif.cation of.its *** modif.cation is based on converting the model to a memristive one,which is a f.rst time in the literature that such idea is used to control this type of.***,we study the system’s stability via the Lyapunov exponents and Poincare maps bef.re and af.er *** order dif.erential equations(f.Es)are commonly utilized to model systems that have memory,and exist in several physical phenomena,models in thermoelasticity f.eld,and biological *** have been utilized to model the realistic biphasic decline manner of.elastic systems and inf.ction of.diseases with a slower rate of.*** are more usef.l than integer-order in modeling sophisticated models that contain physical phenomena.

关键词： RDTM tumor-immune optimal control caputo derivative signal f.ow simulink disease-f.ee equilibrium stability memristive lyapunov exponents poincare map

Solving f.actional Integro-Dif.erential Equations by Using Sumudu Transf.rm Method and Hermite Spectral Collocation Method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2018年第2期54卷 161-180页

作者： Y.A.Amer A.M.S.mahdy E.S.M.Youssef Department of.Mathematics Faculty of Science44519Zagazig UniversityEgypt Department of.Mathematics and Statistics Faculty of ScienceTaif UniversitySaudi Arabia

In this paper we are looking f.rward to f.nding the approximate analytical solutions f.r f.actional integro-dif.erential equations by using Sumudu transf.rm method and Hermite spectral collocation *** f.actional derivatives are described in the Caputo *** applications related to Sumudu transf.rm method and Hermite spectral collocation method have been developed f.r dif.erential equations to the extent of.access to approximate analytical solutions of.f.actional integro-dif.erential equations.

关键词： Caputo derivative integro-dif.erential equations hermite polynomials sumudu transf.rm