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Particuology 2016年第6期14卷 154-161页

作者： ahmed A. Afify Nasser s. Elgazery Department of Mathematics Faculty of Science Helwan University Ain Helwan PO Box 11795 Cairo Egypt Department of Mathematics Faculty of Education Ain Shams University Roxy Heliopolis Cairo Egypt

The influences of the convective boundary condition and heat generation/absorption on magnetohydro- dynamic boundary layer flow of a Maxwell fluid over a stretching surface in the presence of nanoparticles have been numerically investigated. In the model, the physical mechanisms responsible for Brownian motion and thermophoresis with a chemical reaction are considered. similarity equations are derived and then solved using the shooting method with the fourth-order Runge-Kutta integration scheme, The rates of heat and mass transfer are enhanced with a destructive chemical reaction and Blot number. The opposite influence is found with a generative chemical reaction in the presence of Brownian motion and the thermophoretic property.

关键词： Magnetohydrodynamics Nanoparticle Maxwell fluid Boundary layer flow Chemical reaction

V_2O_5·nH_2O nanosheets and multi-walled carbon nanotube composite as a negative electrode for sodium-ion batteries

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Journal of Energy Chemistry 2019年第3期28卷 145-151页

作者： ahmed s. Etman Junliang sun Reza Younesi Department of Materials and Environmental Chemistry (MMK) Stockholm University Department of Chemistry Faculty of science Alexandria University College of Chemistry and Molecular Engineering Peking University ?ngstr?m Advanced Battery Centre Department of Chemistry-?ngstr?m Laboratory Uppsala University

Two dimensional(2D) transition metal oxides and chalcogenides demonstrate a promising performance in sodium-ion batteries(sIBs) application. In this study, we investigated the use of a composite of freeze dried V_2O_5·nH_2O nanosheets and multi-walled carbon nanotube(MWCNT) as a negative electrode material for sIBs. Cyclic voltammetry(CV) results indicated that a reversible sodium-ion insertion/deinsertion into the composite electrode can be obtained in the potential window of 0.1–2.5 V vs. Na^+/Na. The composite electrodes delivered sodium storage capacities of 140 and 45 m Ah g^(-1) under applied current densities of 20 and 100 m A g^(-1), respectively. The pause test during constant current measurement showed a raise in the open circuit potential(OCP) of about 0.46 V, and a charge capacity loss of ～10%. These values are comparable with those reported for hard carbon electrodes. For comparison, electrodes of freeze dried V_2O_5·nH_2O nanosheets were prepared and tested for sIBs application. The results showed that the MWCNT plays a significant role in the electrochemical performance of the composite material.

关键词： sodium-ion batteries Anode materials Vanadium pentoxide nanosheets Composite materials

Relative performance of novel blast wave mitigation system to conventional system based on mitigation percent criteria

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Defence Technology（防务技术） 2021年第3期17卷 912-922页

作者： Moustafa Esa Mostafa s.Amin ahmed Hassan Eng.Mechanics Dept. Military Technical CollegeKobry ElkobbahCairoEgypt Civil Eng.Dept. Military Technical CollegeKobry ElkobbahCairoEgypt

Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist *** of the main embraced strategies is the structural systems that use mitigation *** are developed from a combination of structural elements and described herein as conventional *** the promising techniques is that redirect the waves propagation through hollow *** blast wave propagation through tubes provides an efficient system since it combines many blast wave phenomena,such as reflection,diffraction,and *** this research,a novel blast load mitigation system,employed as a protection fence,is developed using a technique similar to the technique of the bent tube in manipulating the *** relative performance of the novel system to the conventional system is evaluated based on mitigation percent *** of both systems are calculated through numerical *** proposed novel system proved to satisfy high performance in mitigating the generated blast waves from charges weight up to 500 kg TNT at relatively small standoff distances(5 m and 8 m).It mitigates at least 94%of the blast waves,which means that only 6%of that blast impulse is considered as the applied load on the targeted structure.

关键词： Blast mitigation Blast barriers Protection system Mitigation percent Protection evaluation

Visible light-driven photo remediation of hazardous cationic dye via Ce-doped WO_(3) nanostructures

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Journal of Rare Earths 2024年第5期42卷 869-878,I0003页

作者： Azra Haroon Kaseed Anwar Arham s.ahmed Department of Physics Aligarh Muslim University202002AligarhIndia Interdisciplinary Nanotechnology Centre Aligarh Muslim University202002AligarhIndia

Ce-doped WO_(3) nanoparticles were successfully synthesized by the sol-gel method and characterized through advanced characterization *** high resolution transmission electron microscopy(HRTEM)and scanning electron microscopy(sEM)results show a reduction in the agglomeration of nanoparticles upon *** energy dispersive X-ray(EDX)analysis validates the existence of the Ce element in all the doped samples.X-ray photoelectron spectroscopy(XPs)and Raman spectra justify the presence of structural defects(oxygen vacancies)and successful formation of the monoclinic WO_(3) phase,*** Kubelka-Munk function indicates a decrease in band gap with doping,while photoluminescence(PL)spectra show intense visible and UV emissions,significantly,all doped samples exhibit higher photocatalytic performance than pure WO_(3) nanoparticles,with the 6 wt%Ce-doped sample displaying the highest degradation *** with Ce can help to increase the surface area of WO_(3),thereby improving its photoactivity,Moreover,a correlation between PL and photocatalysis is established in the light of oxygen vacancies suggesting a direct dependence of high photocatalytic activity on strong PL signals of WO_(3) *** experiments further reveal that the degradation process is primarily driven by active species,providing insight into a plausible photocatalytic mechanism.

关键词： WO_(3) Rare-earth element Environmental crisis Oxygen vacancies Luminescence Photocatalysis

Combined heat and mass transfer by mixed convection MHD flow along a porous plate with chemical reaction in presence of heat source

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Applied Mathematics and Mechanics(English Edition) 2010年第10期31卷 1217-1230页

作者： J.ZUECO s.ahmed ETs Ingeniería Industrial Departamento de Ingeniería Térmicay FluidosUniversidad Politécnica de Cartagena Fluid Dynamics Research Department of MathematicsGoalpara College

An exact and a numerical solutions to the problem of a steady mixed convective MHD flow of an incompressible viscous electrically conducting fluid past an infinite vertical porous plate with combined heat and mass transfer are presented.A uniform magnetic field is assumed to be applied transversely to the direction of the flow with the consideration of the induced magnetic field with viscous and magnetic dissipations of *** porous plate is subjected to a constant suction velocity as well as a uniform mixed stream *** governing equations are solved by the perturbation technique and a numerical *** analytical expressions for the velocity field,the temperature field,the induced magnetic field,the skin-friction,and the rate of heat transfer at the plate are *** numerical results are demonstrated graphically for various values of the parameters involved in the *** effects of the Hartmann number,the chemical reaction parameter,the magnetic Prandtl number,and the other parameters involved in the velocity field,the temperature field,the concentration field,and the induced magnetic field from the plate to the fluid are *** increase in the heat source/sink or the Eckert number is found to strongly enhance the fluid velocity *** induced magnetic field along the x-direction increases with the increase in the Hartmann number,the magnetic Prandtl number,the heat source/sink,and the viscous *** is found that the flow velocity,the fluid temperature,and the induced magnetic field decrease with the increase in the destructive chemical *** of the study arise in the thermal plasma reactor modelling,the electromagnetic induction,the magnetohydrodynamic transport phenomena in chromatographic systems,and the magnetic field control of materials processing.

关键词： MHD perturbation technique network simulation method Eckert number mixed convection induced magnetic field viscous dissipation heat source/sink

sOME COMPLETELY MONOTONIC FUNCTIONs AssOCIATED WITH THE q-GAMMA AND THE q-POLYGAMMA FUNCTIONs

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Acta Mathematica scientia 2015年第5期35卷 1214-1224页

作者： ahmed sALEM Eid s.KAMEL Department of Basic science Faculty of Information Systems & Computer ScienceOctober 6 University Department of Mathematics Faculty Science Al Jouf University

In this paper, the q-analogue of the stirling formula for the q-gamma function （Moak formula） is exploited to prove the complete monotonicity properties of some functions involving the q-gamma and the q-polygamma functions for all real number q 〉 0. The monotonicity of these functions is used to establish sharp inequalities for the q-gamma and the q-polygamma functions and the q-Harmonic number. Our results are shown to be a generalization of results which were obtained by selvi and Batir [23].

关键词： completely monotonic functions inequalities q-gamma function q-polygammafunction

Interactions between hepatic iron and lipid metabolism with possible relevance to steatohepatitis

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World Journal of Gastroenterology 2012年第34期18卷 4651-4658页

作者： Umbreen ahmed Patricia s Latham Phillip s Oates Department of Physiology Army Medical CollegeNational University of Sciences and TechnologyRawalpindi 46000Pakistan Department of Pathology The George Washington School of Medicine and Health SciencesWashingtonDC 20037United States Physiology M311 AnatomyPhysiology and Human BiologyUniversity of Western AustraliaPerthWA 6009 Australia

The liver is an important site for iron and lipid metabolism and the main site for the interactions between these two metabolic pathways. Although conflicting results have been obtained, most studies support the hypothesis that iron plays a role in hepatic lipogenesis. Iron is an integral part of some enzymes and transporters involved in lipid metabolism and, as such, may exert a direct effect on hepatic lipid load, intrahepatic metabolic pathways and hepatic lipid secretion. On the other hand, iron in its ferrous form may indirectly affect lipid metabolism through its ability to induce oxidative stress and inflammation, a hypothesis which is currently the focus of much research in the field of nonalcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NAsH). The present review will first discuss how iron might directly interact with the metabolism of hepatic lipids and then consider a new perspective on the way in which iron may have a role in the two hit hypothesis for the progression of NAFLD via ferroportinand the iron regulatory molecule hepcidin. The review concludes that iron has important interactions with lipid metabolism in the liver that can impact on the development of NAFLD/NAsH. More defined studies are required to improve our understanding of these effects.

关键词： Lipids Iron Non-alcoholic fatty liver dis-ease/non-alcoholic steatohepatitis Hepcidin Oxidativestress

Real-Time Prediction of Urban Traffic Problems Based on Artificial Intelligence-Enhanced Mobile Ad Hoc Networks(MANETs)

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Computers, Materials & Continua 2024年第5期79卷 1903-1923页

作者： ahmed Alhussen Arshiya s.Ansari Department of Computer Engineering College of Computer and Information SciencesMajmaah UniversityAl-Majmaah11952Saudi Arabia Department of Information Technology College of Computer and Information SciencesMajmaah UniversityAl-Majmaah11952Saudi Arabia

Traffic in today’s cities is a serious problem that increases travel times,negatively affects the environment,and drains financial *** study presents an Artificial Intelligence(AI)augmentedMobile Ad Hoc Networks(MANETs)based real-time prediction paradigm for urban traffic *** are wireless networks that are based on mobile devices and may *** distributed nature of MANETs and the power of AI approaches are leveraged in this framework to provide reliable and timely traffic congestion *** study suggests a unique Chaotic spatial Fuzzy Polynomial Neural Network(CsFPNN)technique to assess real-time data acquired from various sources within *** framework uses the proposed approach to learn from the data and create predictionmodels to detect possible traffic problems and their severity in real ***-time traffic prediction allows for proactive actions like resource allocation,dynamic route advice,and traffic signal optimization to reduce *** framework supports effective decision-making,decreases travel time,lowers fuel use,and enhances overall urban mobility by giving timely information to pedestrians,drivers,and urban *** simulations and real-world datasets are used to test the proposed framework’s prediction accuracy,responsiveness,and *** results show that the suggested framework successfully anticipates urban traffic issues in real-time,enables proactive traffic management,and aids in creating smarter,more sustainable cities.

关键词： Mobile AdHocNetworks(MANET) urban traffic prediction artificial intelligence(AI) traffic congestion chaotic spatial fuzzy polynomial neural network(CsFPNN)

Comparative study between gas phase and liquid phase for the production of DMC from methanol and CO_2

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Journal of Natural Gas Chemistry 2012年第2期21卷 189-193页

作者： ahmed Aouissi salem s. Al-Deyab Department of Chemistry King Saud University

Direct synthesis of dimethyl carbonate （DMC） from methanol and carbon dioxide over Co1.5PW12O40 in liquid and in gas phase is investigated. The synthesized catalyst has been characterized by means of FTIR and XRD. Liquid phase experiment results showed that high pressures are favorable for the synthesis of DMC. However, DMC formation is limited by the reaction with co-produced water. DMC selectivity is more strongly dependent on the temperature than on the pressure of CO2. As for the reactions in gas phase, it has been found that both CH3OH conversion and DMC selectivity decreased with increasing temperature, owing to the decomposition of DMC at high temperatures. High temperatures and more amount of Co1.5PW12O40 catalyst favor the formation of dimethoxymethane （DMM） and methyl formate （MF）.

关键词： heteropolyanion Keggin structure methanol dimethyl carbonate carbon dioxide

Oilfield produced water treatment in internal-loop airlift reactor using electrocoagulation/flotation technique

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Chinese Journal of Chemical Engineering 2018年第4期26卷 879-885页

作者： saad H.Ammar ahmed s.Akbar Department of Chemical engineering AL-Nahrain University

Oilfield produced water is large quantities of salty water trapped in underground formations and subsisted under high temperatures and pressures that are brought to the surface along with oil during production. Produced water(PW) contains a lot of pollutants such as hydrocarbons and metals, this water must be treated before disposal. Therefore, different techniques are being used to treat produced water. Electrocoagulation is an efficient treatment technique involving the dissolution of anodes and formation of electro-coagulants, while the simultaneous generation of H_2 bubbles at the cathode leads to the pollutant removal by flotation. Electrocoagulation(EC)method is one of the most promising and widely used processes to treat oilfield produced water. In the present work, a conventional internal-loop(draught tube) airlift reactor was utilized as electrocoagulation/flotation cell for PW treatment by inserting two aluminum electrodes in the riser section of the airlift reactor. The EC airlift reactor was operated in a batch mode for the liquid phase. Different experimental parameters were studied on the oil and turbidity removal efficiencies such as current density, initial pH, electrocoagulation time, and air *** experimental results showed that mixing of the oil droplets in the PW was accomplished using only the liquid recirculation resulted by H_2 microbubbles generated by EC process which enhanced the oil removal. The experimental results further showed that the EC time required achieving ≥ 90% oil removal efficiency decreases from 46 to 15 min when operating current density increases from 6.8 to 45.5 mA·cm^(-2). This reactor type was found to be highly efficient and less energy consuming compared to conventional existing electrochemical cells which used mechanical agitation.

关键词： Produced water Wastewater treatment Electrocoagulation/flotation Internal loop Airlift reactor