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Spectral collocation method for solving continuous population models for single and interacting species by means of exponential Chebyshev approximation

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International Journal of Biomathematics 2018年第8期11卷 265-288页

作者： m. A. Ramadan m. A. abd el salam mathematics Department Faculty of Science Menoufia University Shebin El-KomEgypt mathematics Department Faculty of Science Al-Azhar University Nasr-City Cairo Egypt

In this paper, an efficient and accurate method is presented to solve continuous population models for single and interacting species using spectral collocation method with exponential Chebyshev (EC) functions. The first problem is a logistic growth model in a population, while the second problem is a prey-predator model: Lotka-Volterra system, the tbird is a simple 2-species Lotka-Volterra competition model, and the final one is a prey-predator model with limit cycle periodic behavior. The high accuracy of this method is verified through some numerical examples. The obtained numerical results are compared with other methods, showing that the proposed method gives higher accuracy.

关键词： Exponential Chebyshev functions continuous population models spectral collocation method

PERIODIC mOTIONS OF SPINNING RIGID SPACECRAFT UNDER INFLUENCE OF GRAVITATIONAL AND mAGNETIC FIelDS

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Applied mathematics and mechanics(English Edition) 2006年第8期27卷 1061-1069页

作者： Yehia A.abdel-aziz m.h.Yehia F.A.abd el-salam m.Radwan National Research Institute of Astronomy and Geophysics Helwan. Cairo Egypt mathematics Department Faculty of Science Mansoura University MansouraEgypt Astronomy Department Faculty of ScienceCairo UniversityCairo12613Egypt

The motion of a magnetized axisymmetric spacecraft about its center of mass in a circular orbit is considered, taking the gravitational and magnetic effects of the central body into account. Equations of motion of the reduced system are transformed to equations of plane motion of a charged particle under the action of electric and magnetic fields. Stationary motions of the system are determined and periodic motions near to them are constructed using the Lyapounoff theorem of the holomorphic integral.

关键词： periodic motions routhian rigid spacecraft

Position and Velocity Time Delay for Suppression Vibrations of a hybrid Rayleigh-Van der Pol-Duffing Oscillator

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Sound & Vibration 2020年第3期54卷 149-161页

作者： Y.A.Amer A.T.el-Sayed m.N.abd el-salam mathematics Department Science FacultyZagazig UniversityZagazigEgypt Basic Sciences Department Modern Academy for Engineering and TechnologyCairoEgypt Basic Sciences Department Higher Technological Institute10th of Ramadan CityEgypt

In this paper,we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing *** system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external *** applied the multiple scales method to get the solution from first *** and numerically,we studied the system before and after adding time delay feedback at the primary resonance case(ffi!).We used mATLAB program to simulate the efficacy of different parameters and the time delay on the main system.

关键词： Position time delay feedback velocity time delay feedback multiple scales method resonance cases

A Suitable Active Control for Suppression the Vibrations of a Cantilever Beam

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Sound & Vibration 2022年第2期56卷 89-104页

In our consideration,a comparison between four different types of controllers for suppression the vibrations of the cantilever beam excited by an external force is carried *** four types are the linear velocity feedback control,the cubic velocity feedback control,the non-linear saturation controller(NSC)and the positive position feedback(PPF)*** suitable type is the PPF controller for suppression the vibrations of the cantilever *** approximate solution obtained up to the first approximation by using the multiple scale *** PPF controller effectiveness is studied on the *** used frequency-response equations to investigate the stability of a cantilever *** notified that,there is a good agreement between the analytical solution and the numerical solution.

关键词： Cantilever beam cubic velocity feedback control linear velocity feedback control non-linear saturation controller(NSC) positive position feedback(PPF)controller

Biochemical changes in phenols,flavonoids,tannins,vitamin E,β-carotene and antioxidant activity during soaking of three white sorghum varieties

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Asian Pacific Journal of Tropical Biomedicine 2012年第3期2卷 203-209页

作者： abd el-moneim mR Afify hossam S el-Beltagi Samiha m abd el-salam Azza A Omran Department of Biochemistry Faculty of AgricultureCairo University Department of Crops Technology Food Technology Research InstituteAgricultural Research CenterEgypt

Objective:To investigate the changes in total phenols,flavonoids,tannins,vitamin E, β-carotene and antioxidant activity during soaking of three white sorghum ***: The changes in total phenols,total ilavonoids,tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity during soaking of sorghum grains were ***:Total phenols,total flavonoids,tannins,vitamin E,P-carotene and antioxidant activity in raw sorghum were ranged from 109.21 to 116.70,45.91 to 54.69,1.39 to 21.79 mg/100 g,1.74 to 5.25,0.54 to 1.19 mg/kg and 21.72%to 27.69%and 25.29%to 31.97%,respectively. The above measured compounds were significantly decreased after soaking.p-hydroxybenzoic acid,vanillic acid,syringic acid and cinnamic acid represent the major phenolic acids in Dorado *** ferulic acid,p-coumaric acid,gallic acid and caffeic acid represent the major phenolic acids in *** the other hand,protocatechuic acid represents the major phenolic acids in *** flavonoids components,Dorado was the highest variety in kampferol and naringenin while Shandaweel-6 was the highest variety in luteolin, apigenin,hypersoid,quercelin and ***,Giza-15 was the highest variety in catechin. Phenolic acids,flavonoid compounds and antioxidant activities were decreased after soaking. Conclusions:Sorghum varieties have moderate quantities from total phenols,total flavonoids, tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity which decreased after soaking.

关键词： Sorghum Soaking Total phenols Flavonoids Tannins Vitamin E β-carotene Antioxidant activity Phenolic acids Flavonoid components Biochemical change

Swarming Behavior of harris hawks Optimizer for Arabic Opinion mining

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Computers, materials & Continua 2021年第12期69卷 4129-4149页

作者： Diaa salam abd elminaam Nabil Neggaz Ibrahim abdulatief Ahmed Ahmed el Sawy Abouelyazed Department of Information Systems Faculty of Computers and Artificial IntelligenceBenha University12311Egypt Department of Computer Science Faculty of Computer ScienceMisr International UniversityEgypt Universite des Sciences at de la Technologie d’Oran mohamed Boudiaf USTO-MBBP 1505EL M’naouer31000 OranLaboratoire Signal Image Parole(SIMPA)Department d’informatiqueFaculte des Mathematiques et InformatiqueAlgerie Department of Computer Science Faculty of Computers and Artificial IntelligenceBenha University12311Egypt Department of Computer Science Obour High Institute for Computers and InformaticsEgypt

At present,the immense development of social networks allows generating a significant amount of textual data,which has facilitated researchers to explore the field of opinion *** addition,the processing of textual opinions based on the term frequency-inverse document frequency method gives rise to a dimensionality *** study aims to detect the nature of opinions in the Arabic language employing a swarm intelligence(SI)-based algorithm,harris hawks algorithm,to select the most relevant *** experimental study has been tested on two datasets:Arabic Jordanian General Tweets and Opinion Corpus for *** terms of accuracy and number of features,the results are better than those of other SI based algorithms,such as grey wolf optimizer and grasshopper optimization algorithm,and other algorithms in the literature,such as differential evolution,genetic algorithm,particle swarm optimization,basic and enhanced whale optimizer algorithm,slap swarm algorithm,and ant–lion optimizer.

关键词： Arabic opinion mining harris hawks optimizer feature selection AJGT and OCA datasets

Assessment of coal gasification in a pressurized fixed bed gasifier using an ASPEN plus and Euler–Euler model

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International Journal of Coal Science & Technology 2020年第3期7卷 516-535页

作者： Tamer m.Ismail mingliang Shi Jianliang Xu Xueli Chen Fuchen Wang m.abd el-salam mechanical Engineering Department Suez Canal UniversityIsmailiaEgypt Key Laboratory of Coal Gasification and Energy Chemical Engineering of ministry of Education East China University of Science and TechnologyShanghaiChina Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyShanghaiChina Department of Basic Science Cairo UniversityGizaEgypt

With the help of Aspen Plus,a two-dimensional unsteady CFD model is developed to simulate the coal gasification process in a fixed bed gasifier.A developed and validated two dimensional CFD model for coal gasification has been used to predict and assess the viability of the syngas generation from coal gasification employing the updraft fixed bed *** process rate model and the sub-model of gas generation are *** particle size variation and char burning during gasification are also taken into *** order to verify the model and increase the understanding of gasification characteristics,a set of experiments and numerical comparisons have been carried *** simulated results in the bed are used to predict the composition of syngas and the conversion of *** model proposed in this paper is a promising tool for simulating the coal gasification process in a fixed bed gasifier.

关键词： Fixed bed gasifier Aspen plus Euler-Euler model Coal

Numerical and experimental analysis for simulating fuel reactor in chemical looping combustor system

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International Journal of Coal Science & Technology 2020年第3期7卷 551-559页

作者： Tamer m.Ismail Lu Ding Khaled Ramzy mabd el-salam Department of mechanical Engineering Suez Canal UniversityIsmailiaEgypt Institute of Clean Coal Technology East China University of Science and TechnologyShanghai200237China Department of Basic Science Cairo UniversityGizaEgypt

The greenhouse problem has a significant effect on our communities such as,health and *** dioxide is one of the main gases that cause global ***,CO2 capture techniques have been the focus of attention these *** chemical looping combustion technique adopted the air reactor and fuel reactor to recycle heat *** study presents a numerical and experimental investigation on a fuel reactor in chemical looping combustor(CLC)*** present numerical model is introduced by the kinetic theory of granular flow and coupled with gas–solid flow with chemical reactions to simulate the combustion of solids in the *** k–εturbulent model was used to model the gas phase and the particle *** developed model simplify the prediction of flow patterns,particle velocities,gas velocities,and composition profiles of gas products and the distribution of heterogeneous reaction rates under the same operating *** predicted and experimental results were compared according to the basis of determination coefficient(R2).In addition the results showed that there is a good agreement between the predicted and experimental *** value of(R2)for CO,CO2 and Ch4 was 0.959,0.925 and 0.969 *** shows that the present model is a promising simulation for solid particle combustion and gives the power direction for the design and optimization of the CLC systems.

关键词： Chemical looping combustion mathematical modeling Fluidized bed Coal Kinetic model

Simulation of buoyancy-induced turbulent flow from a hot horizontal jet

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Journal of hydrodynamics 2014年第1期26卷 104-113页

作者： el-AmIN m.F. SUN Shuyu salam Amgad Computational Transport Phenomena Laboratory (CTPL) Division of Physical Sciences and EngineeringKing Abdullah University of Science and Technology

Experimental visualizations and numerical simulations of a horizontal hot water jet entering cold water into a rectangular storage tank are described. Three different temperature differences and their corresponding Reynolds numbers are considered. Both experimental visualization and numerical computations are carried out for the same flow and thermal conditions. The realizable k-e model is used for modeling the turbulent flow while the buoyancy is modeled using the Boussinesq approximation. Polynomial approximations of the water properties are used to compare with the Boussinesq approximation. Numerical solutions are obtained for unsteady flow while pressure, velocity, temperature and turbulence distributions inside the water tank as well as the Froude number are analyzed. The experimental visualizations are performed at intervals of five seconds for all different cases. The simulated results are compared with the visualized results, and both of them show the stratification phenomena and buoyancy force effects due to temperature difference and density variation. After certain times, depending on the case condition, the flow tends to reach a steady state.

关键词： turbulent flow realizablc k - e turbulence model heat transfer jet heat storage