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Frontiers of Environmental Science & Engineering 2024年第10期18卷 15-48页

作者： mahmoud a.ahmed Safwat A.mahmoud Ashraf A.Mohamed Veolia Water Technologies Cairo 11835Egypt Chemistry department Faculty of ScienceAin Shams UniversityCairo 11566Egypt Physics Department Faculty of ScienceNorthern Border UniversityArar 13211Saudi Arabia

Microbiologically induced corrosion(MIC)is a complex and destructive phenomenon that occurs in various sectors,involving the interaction between microorganisms and metal surfaces,resulting in accelerated corrosion *** review article provides a comprehensive analysis of MIC,encompassing microbial species involved,their metabolic activities,and influential environmental factors driving the corrosion *** mechanisms of MIC,both in the presence and absence of oxygen,are explored,along with the diverse effects of microbes on different types of corrosion and their economic *** and monitoring techniques,including traditional and advanced methods such as microbiological and electrochemical methods,are ***,it examines preventive and control measures,such as the use of biocides and their mechanisms of *** to enhance the performance of these control measures and the effectiveness of antimicrobial agents during disinfection processes,including surfactants and chelators,are ***,the review highlights enzymatic remediation as a sustainable alternative approach,providing detailed *** challenges in mitigating MIC and potential future developments and collaborative opportunities are also *** systematic review is a valuable resource for researchers,industry professionals,and policymakers seeking a comprehensive understanding of the complex phenomenon of MIC and effective strategies for its management.

关键词： Metal failure Biofilm formation Enzymatic remediation Antimicrobial agents Bio-corrosion mechanisms

A Comparative Study on the Corrosion Performance of Ni_(47)Ti_(49)Co_4 and Ni_(51)Ti_(49) Shape Memory Alloys in Simulated Saliva Solution for Dental Applications

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Acta Metallurgica Sinica(English Letters) 2016年第11期29卷 1001-1010页

作者： Rasha a.ahmed Chemistry Department Faculty of Science Taif University Forensic Chemistry Laboratories Medico Legal DepartmentMinistry of Justice

In this study, the corrosion behavior of Ni47Ti49Co4 shape memory alloy（SMA） was investigated in simulated saliva solution with the binary alloy Ni（51）Ti49 as a reference. The surface morphology and the chemical composition of the oxide films were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy before and after immersion in the test solutions, respectively. The results showed that the ternary alloy was less affected by the test solution,owning to the formation of passive layer composed mainly of the oxides of titanium and cobalt in several oxidation *** voltammetry, electrochemical impedance spectroscopy and potentiodynamic polarization measurements affirmed that the passive oxide film significantly improved the corrosion resistance of Ni47Ti49Co4 SMAs as demonstrated by the smaller corrosion current density, larger resistance and smaller capacitance. Consequently, alloying with cobalt, which has paramount importance in enhancing the passive layer, expands the use of Ni47Ti49Co4 SMAs in dental work as new nitinol alloys with high corrosion resistances.

关键词： Ni47Ti49Co4 Shape memory alloy (SMA) Corrosion Artificial saliva X-ray photoelectronspectroscopy (XPS)

Improved narrow wavelength band blocking filters

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Chinese Optics Letters 2009年第4期7卷 352-354页

作者： Hayder a.ahmed Physics Department College of ScienceBasrah University

A design approach is described to achieve spectral blocking filters of any spectral width and optical density for narrow blocking bands. We give new criterions to find the necessary number of layers from the desired bandwidth and optical density, and give new estimate equations which describe the number of layers required for designing a blocking filter of given bandwidth, high index, and optical density. This approach can be useful for laser line blocking, night vision filters, and many other general applications.

关键词： Bandpass filters Bandwidth Density measurement (optical)

Boundary layer flow of Maxwell fluid due to torsional motion of cylinder: modeling and simulation

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Applied Mathematics and Mechanics(English Edition) 2020年第4期41卷 667-680页

作者： M.KHAN a.ahmed J.ahmed Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

This paper investigates the boundary layer flow of the Maxwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse magnetic *** constitutive flow equations for the current physical problem are modeled and analyzed for the first time in the *** torsional motion of the cylinder is considered with the constant azimuthal velocity *** partial differential equations(PDEs)governing the torsional motion of the Maxwell fluid together with energy transport are simplified with the boundary layer *** current analysis is valid only for a certain range of the positive Reynolds ***,for very large Reynolds numbers,the flow becomes ***,the governing similarity equations are simplified through suitable transformations for the analysis of the large Reynolds *** numerical simulations for the flow,heat,and mass transport phenomena are carried out in view of the bvp4c scheme in *** outcomes reveal that the velocity decays exponentially faster and reduces for higher values of the Reynolds numbers and the flow penetrates shallower into the free stream *** is also noted that the phenomenon of stress relaxation,described by the Deborah number,causes to decline the flow fields and enhance the thermal and solutal energy transport during the fluid *** penetration depth decreases for the transport of heat and mass in the fluid with the higher Reynolds *** excellent validation of the numerical results is assured through tabular data with the existing literature.

关键词： torsional motion Maxwell fluid magnetic field stretchable rotating cylinder bvp4c scheme

Transient flow of magnetized Maxwell nanofluid: Buongiorno model perspective of Cattaneo-Christov theory

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Applied Mathematics and Mechanics(English Edition) 2020年第4期41卷 655-666页

作者： M.KHAN a.ahmed J.ahmed Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

The present research article is devoted to studying the characteristics of Cattaneo-Christov heat and mass fluxes in the Maxwell nanofluid flow caused by a stretching sheet with the magnetic field *** Maxwell nanofluid is investigated with the impact of the Lorentz force to examine the consequence of a magnetic field on the flow characteristics and the transport of *** heat and mass transport mechanisms in the current physical model are analyzed with the modified versions of Fourier’s and Fick’s laws,***,the well-known Buongiorno model for the nanofluids is first introduced together with the Cattaneo-Christov heat and mass fluxes during the transient motion of the Maxwell *** governing partial differential equations(PDEs)for the flow and energy transport phenomena are obtained by using the Maxwell model and the Cattaneo-Christov theory in addition to the laws of *** transformations are used to convert the PDEs into a system of nonlinear ordinary differential equations(ODEs).The homotopic solution methodology is applied to the nonlinear differential system for an analytic *** results for the time relaxation parameter in the flow,thermal energy,and mass transport equations are discussed *** is noted that higher values of the thermal and solutal relaxation time parameters in the Cattaneo-Christov heat and mass fluxes decline the thermal and concentration fields of the ***,larger values of the thermophoretic force enhance the heat and mass transport in the ***,the Brownian motion of the nanoparticles declines the concentration field and increases the temperature *** validation of the results is assured with the help of numerical tabular data for the surface velocity gradient.

关键词： transient flow Cattaneo-Christov theory Maxwell nanofluid Buongiorno model homotopy analysis method (HAM) solution

Thermal analysis in swirl motion of Maxwell nanofluid over a rotating circular cylinder

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Applied Mathematics and Mechanics(English Edition) 2020年第9期41卷 1417-1430页

作者： a.ahmed M.KHAN J.ahmed Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

In this paper,the mechanism of thermal energy transport in swirling flow of the Maxwell nanofluid induced by a stretchable rotating cylinder is *** rotation of the cylinder is kept constant in order to avoid the induced axially secondary ***,the novel features of heat generation/absorption,thermal radiation,and Joule heating are studied to control the rate of heat *** effects of Brownian and thermophoretic forces exerted by the Maxwell nanofluid to the transport of thermal energy are investigated by utilizing an effective model for the nanofluid proposed by *** whole physical problem of fluid flow and thermal energy transport is modelled in the form of partial differential equations(PDEs)and transformed into nonlinear ordinary differential equations(ODEs)with the help of the suitable flow *** acquired results through the technique bvp4c are reported graphically with physical *** analysis reveals that there is higher transport of heat energy in the Maxwell nanoliquid for a constant wall temperature(CWT)as compared with the prescribed surface temperature(PST).Both thermophoretic and Brownian forces enhance the thermal energy transport in the flowing Maxwell ***,the temperature distribution increases with increasing values of the radiation parameter and the Eckert *** is also noted that an increase in Reynolds number reduces the penetration depth,and as a result the flow and transport of energy occur only near the surface of the cylinder.

关键词： Maxwell nanofluid rotating cylinder heat source/sink Joule heating convective condition numerical solution

Repurposing verapamil for prevention of cognitive decline in sporadic Alzheimer's disease

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Neural Regeneration Research 2022年第5期17卷 1018-1019页

作者： Heba a.ahmed Tauheed Ishrat Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA Pharmaceutical Sciences Neuroscience InstituteUniversity of Tennessee Health Science CenterMemphisTNUSA

Dementia is currently the only leading cause of death that is still on the rise,with its overall costs already surpassing those of cancer and heart disease combined,it has developed into a worldwide *** response to its serious and far-reaching effects,the US government has established the"National Alzheimer's Project Act"(Public Law 111-375).

关键词： Alzheimer prevention death verapamil

Rotational flow of Oldroyd-B nanofluid subject to Cattaneo-Christov double diffusion theory

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Applied Mathematics and Mechanics(English Edition) 2020年第7期41卷 1083-1094页

作者： A.HAFEEZ M.KHAN a.ahmed J.ahmed Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

A nanofluid is composed of a base fluid component and nanoparticles, in which the nanoparticles are dispersed in the base fluid. The addition of nanoparticles into a base fluid can remarkably improve the thermal conductivity of the nanofluid, and such an increment of thermal conductivity can play an important role in improving the heat transfer rate of the base fluid. Further, the dynamics of non-Newtonian fluids along with nanoparticles is quite interesting with numerous industrial applications. The present predominately predictive modeling studies the flow of the viscoelastic Oldroyd-B fluid over a rotating disk in the presence of nanoparticles. A progressive amendment in the heat and concentration equations is made by exploiting the Cattaneo-Christov heat and mass flux expressions. The characteristic of the Lorentz force due to the magnetic field applied normal to the disk is studied. The Buongiorno model together with the Cattaneo-Christov theory is implemented in the Oldroyd-B nanofluid flow to investigate the heat and mass transport mechanism. This theory predicts the characteristics of the fluid thermal and solutal relaxation time on the boundary layer flow. The von K′arm′an similarity functions are utilized to convert the partial differential equations(PDEs) into ordinary differential equations(ODEs). A homotopic approach for obtaining the analytical solutions to the governing nonlinear problem is carried out. The graphical results are obtained for the velocity field, temperature, and concentration distributions. Comparisons are made for a limiting case between the numerical and analytical solutions, and the results are found in good agreement. The results reveal that the thermal and solutal relaxation time parameters diminish the temperature and concentration distributions, respectively. The axial flow decreases in the downward direction for higher values of the retardation time parameter. The impact of the thermophoresis parameter boosts the temperature di

关键词： Oldroyd-B nanofluid rotating disk magnetohydrodynamic(MHD) Cattaneo-Christov theory analytical solution

Von Kármán rotating flow of Maxwell nanofluids featuring the Cattaneo-Christov theory with a Buongiorno model

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Applied Mathematics and Mechanics(English Edition) 2020年第8期41卷 1195-1208页

作者： a.ahmed M.KHAN J.ahmed A.HAFEEZ Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

This research paper analyzes the transport of thermal and solutal energy in the Maxwell nanofluid flow induced above the disk which is rotating with a constant angular *** significant features of thermal and solutal relaxation times of fluids are studied with a Cattaneo-Christov double diffusion theory rather than the classical Fourier’s and Fick’s laws.A novel idea of a Buongiorno nanofluid model together with the Cattaneo-Christov theory is introduced for the first time for the Maxwell fluid flow over a rotating ***,the thermal and solutal distributions are controlled with the impacts of heat source and chemical *** classical von Karman similarities are used to acquire the non-linear system of ordinary differential equations(ODEs).The analytical series solution to the governing ODEs is obtained with the well-known homotopy analysis method(HAM).The validation of results is provided with the published results by the comparison *** graphically presented outcomes for the physical problem reveal that the higher values of the stretching strength parameter enhance the radial velocity and decline the circumferential *** increasing trend is noted for the axial velocity profile in the downward direction with the higher values of the stretching strength *** higher values of the relaxation time parameters in the Cattaneo-Christov theory decrease the thermal and solutal energy transport in the flow of Maxwell *** higher rate of the heat transport is observed in the case of a larger thermophoretic force.

关键词： Maxwell fluid nanoparticle Cattaneo-Christov theory rotating disk homotopy analysis method(HAM)

Remote Monitoring of Electric Vehicle Charging Stations in Smart Campus Parking Lot

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Journal of Modern Power Systems and Clean Energy 2020年第1期8卷 124-132页

作者： Mohamed a.ahmed Mohamed R.El-Sharkawy Young-Chon Kim Department of Electronic Engineering Universidad Técnica Federico Santa MaríaValparaíso 2390123Chile Department of Communications and Electronics Higher Institute of Engineering&TechnologyKing MarriottAlexandria 23713Egypt Department of Automotive and Tractor Engineering Minia UniversityEl-Minia 61111Egypt Department of Computer Engineering Chonbuk National UniversityJeonju 561-756Korea

Smart parking lots are smart places capable of supporting both parking and charging services for electric vehicles(EVs).In order to manage EV charging,the parking lot local controller(PLLC)requires data exchange with EV charging stations(EVCSs)through communication ***,data losses and communication delays are unavoidable and may significantly degrade the system *** work aims to investigate the underlying communication networks for remote monitoring of EVCSs in a smart campus parking *** communication network consists of two subnetworks:parking area network(PAN)and campus area network(CAN).PAN covers communication among EVs,charging stations and PLLC,while CAN enables dedicated communication between PLLCs and a global controller of the *** one of the major obstacles in EV system is the lack of unified communication architecture to integrate EVCS in the power grid,we develop communication models for the in-vehicle system and EVCSs based on logical node concept of IEC 61850 ***,we implement network models for EVCSs using OPNET *** communication technologies and configurations are considered in modeling and simulations,and end-toend delay is evaluated and discussed.

关键词： Communication network electric vehicle(EV) electric vehicle charging station(EVCS) IEC 61850 OPNET smart parking lot