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Fluid Dynamics & Materials Processing 2023年第6期19卷 1535-1549页

作者： ahmad s.awad Banan Hudaib Waid Omar Mechanical Engineering Department Faculty of Engineering TechnologyAl-Balqa Applied UniversityAmman11134Jordan Chemical Engineering Department Faculty of Engineering TechnologyAl-Balqa Applied UniversityAmman11134Jordan

In this study,the potential of a low-cost bio-adsorbent,taken directly from Date Palm Trunk Fibers(DPTF)agricultural wastes,for cadmium ions removal from wastewaters is *** performances of this adsorbent are evaluated by building breakthrough curves at different bed heights and flow rates while keeping other parameters,such as the initial feed concentration,pH,and particle size,*** results indicate that the maximum cadmium adsorption capacity of DTPF can be obtained from the Thomas model as 51.5 mg/g with the most extended mass transfer zone of 83 min at the lowest flow rate at 5 ml/*** saturation concentrations(NO)and the rate constant(kab)obtained from the BDsT(bed depth service time)model are 7022.16 mg/l and 0.0536 l/***,*** the Yon-Nelsen Model,it is found that operating at a lower flow rate leads to a larger value of the elapsed needed time to reach a 50%*** Wolborska model indicates that the bed capacity increases with decreasing the flow rate,and the adsorbent can achieve a greater external mass transfer kinetic coefficient(2.271/min)at a higher flow rate.

关键词： Cadmium ions adsorption fixed bed biodorbent pollutant date palm trunk fibers wastewater treatment breakthrough curves modeling

Thermospheric neutral wind studies over the equatorial region:A review

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Earth and Planetary Physics 2025年第1期9卷 81-100页

作者： siti syazwani Nasuha Idahwati sarudin Nurul shazana Abdul Hamid ahmad Fairuz Omar school of Physics Universiti Sains Malaysia11800 USMPulau PinangMalaysia Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia space science Centre(ANGKAsA) Institute of Climate ChangesUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia

Thermospheric neutral winds(TNWs)refer to the neutral gases in the thermosphere circulating as tides,which play a crucial role in the dynamics of the thermosphere-ionosphere system(TIs).Global geospace neutral winds,particularly over the magnetic equator,have been a subject of study for several ***,despite the known importance of neutral winds,a comprehensive understanding and characterization of the winds is still *** ground-based and satellite missions have provided valuable information on the contribution of neutral winds to the global atmospheric ***,efforts in the global monitoring of neutral winds are still lacking,and the drivers behind the behavior of TNWs as well as their influence on the TIs remain *** address these knowledge gaps in the global circulation of TNWs,it is crucial to develop a deep understanding of the neutral wind characteristics over different *** low-latitude equatorial region in particular has been observed to exert complex influences on TNWs because of the unique effects of the Earth’s magnetic field at the dip *** neutral winds over this region will provide valuable insights into the unique dynamics and processes that occur in this region,thereby enhancing our understanding of their role in the overall dynamics of the ***,through empirical observations,an improved ability to accurately model and predict the behavior of this region can be *** review article addresses challenges in understanding equatorial winds by reviewing historical measurements,current missions,and the interactions of ionospheric and thermospheric phenomena,emphasizing the need for comprehensive measurements to improve global atmospheric dynamics and weather forecasting.

关键词： thermospheric neutral wind thermosphere-ionosphere system dip equator equatorial region

Leaching of styrene and other aromatic compounds in drinking water from Ps bottles

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Journal of Environmental sciences 2007年第4期19卷 421-426页

作者： Maqbool ahmad ahmad s. Bajahlan Environmental Control Department Directorate General for Royal Commission at Yanbu P.O.Box 30031 Yanbu Al-SinaiyahKingdom of Saudi Arabia

Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene （Ps） bottles used locally for packaging. Water sapmles in contact with Ps were extracted by a preconcentration technique called as ＂purge and trap＂ and analysed by gas chromatograph-mass spectrometer （GC/Ms）. Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in Ps bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In styrofoam and Ps cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from styrofoam cups. Paper cups were found to be safe for hot drinks.

关键词： styrene polystyrene (Ps) ethyl benzene leaching styrofoam

Magnetic force microscopy of an operational spin nano-oscillator

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Microsystems & Nanoengineering 2022年第3期8卷 247-252页

作者： seyed Amir Hossein Banuazizi Afshin Houshang ahmad A awad Javad Mohammadi Johan Akerman Liubov M.Belova Faculty of New sciences and Technologies University of TehranTehranIran Materials and Nanophysics Department of Applied PhysicsSchool ofEngineering SciencesKTH Royal Institute of Technology11419 StockholmSweden Department of Physics University of Gothenburg41296 GothenburgSweden Department of Materials science and Engineering KTHRoyal Institute of Technology10044 StockholmSweden

Magnetic force microscopy(MFM)is a powerful technique for studying magnetic microstructures and nanostructures that relies on force detection by a cantilever with a magnetic *** detected magnetic tip interactions are used to reconstruct the magnetic structure of the sample ***,we demonstrate a new method using MFM for probing the spatial profle of an operational nanoscale spintronic device,the spin Hall nano-osillator(sHNO),which generates high-intensity spin wave auto-osillations enabling novel microwave applications in magnonics and neuromorphic *** developed an MFM system by adding a microwave probe station to allow electrical and microwave characterization up to 40 GHz during the MFM ***-based on NiFe/Pt bilayers with a specific design compatible with the developed system-were fabricated and scanned using a Co magnetic force microscopy tip with 10 nm spatial MFM resolution,while a DC current sufficient to induce auto-oscillation *** results show that this developed method provides a promising path for the characterization and nanoscale magnetic field imaging of operational nano-osilators.

关键词： microwave characterization system

Physical and Kinematical Characteristics of Wolf–Rayet Central stars and their Host Planetary Nebulae

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Research in Astronomy and Astrophysics 2023年第9期23卷 219-240页

作者： Z.awad A.Ali Department of Astronomy Space Science and MeteorologyFaculty of ScienceCairo University12613 Giza

We address the physical and kinematical properties of Wolf–Rayet[WR]central stars(Css)and their host planetary nebulae(PNe).The studied sample comprises all[WR]Css that are currently *** analysis is based on recent observations of the parallax,proper motion,and color index of[WR]Css from the Gaia space mission’s early third release(eDR3)catalog,as well as common nebular *** results revealed an evolutionary sequence,in terms of decreasing Teff,from the early hot[WO 1]to the late cold[WC 12]*** evolutionary sequence extends beyond[WR]Cs temperature and luminosity to additional Cs and nebular *** statistical analysis shows that the mean final stellar mass and evolutionary age of the[WR]Cs sample are 0.595±0.13M⊙and 9449±2437 yr,respectively,with a mean nebular dynamical age of 7270±1380 *** addition,we recognize that the color of the majority(∼85%)of[WR]Css tends to be red rather than their genuine blue *** analysis indicates that two-thirds of the apparent red color of most[WR]s is attributed to the interstellar extinction whereas the other one-third is due to the PN self-extinction effect.

关键词： Wolf-Rayet-(IsM )planetary nebulae general-IsM kinematics and dynamics

Roll-pitch-yaw autopilot design for nonlinear time-varying missile using partial state observer based global fast terminal sliding mode control

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Chinese Journal of Aeronautics 2016年第5期29卷 1302-1312页

作者： Ahmed awad Wang Haoping sino-French International Joint Laboratory of Automatic Control and signal Processing (LaFCAs) School of AutomationNanjing University of Science & Technology

The acceleration autopilot design for skid-to-turn （sTT） missile faces a great challenge owing to coupling effect among planes, variation of missile velocity and its parameters, inexistence of a complete state vector, and nonlinear aerodynamics. Moreover, the autopilot should be designed for the entire flight envelope where fast variations exist. In this paper, a design of integrated roll-pitch-yaw autopilot based on global fast terminal sliding mode control （GFTsMC） with a partial state nonlinear observer （PsNLO） for sTT nonlinear time-varying missile model, is employed to address these issues. GFTsMC with a novel sliding surface is proposed to nullify the integral error and the singularity problem without application of the sign function. The proposed autopilot consisting of two-loop structure, controls sTT maneuver and stabilizes the rolling with a PsNLO in order to estimate the immeasurable states as an output while its inputs are missile measurable states and control signals. The missile model considers the velocity variation, gravity effect and parameters＇ variation. Furthermore, the environmental conditions＇ dynamics are mod- eled. PsNLO stability and the closed loop system stability are studied. Finally, numerical simulation is established to evaluate the proposed autopilot performance and to compare it with existing approaches in the literature.

关键词： Flight control system Global fast terminal slidingmode control Integrated autopilot Nonlinear state observer skid-to-turn missile

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Journal of Rare Earths 2018年第10期36卷 1106-1111页

作者： sardar ahmad M.shafiq Rashid ahmad s.Jalali-Asadabadi Iftikhar ahmad Department of Chemistry University of Malakand Center for Computational Materials science University of Malakand Department of Physics Abbottabad University of Science and Technology Department of Physics Faculty of SciencesUniversity of Isfahan

In this paper, we explored the structural, elastic and mechanical properties of the strongly correlated electron systems, intermetallic Ln-Au（Ln = Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu） in cubic structure,using PF-LAPW method within the density functional theory. structural properties of these intermetallics were investigated by treating the exchange-correlation potential with the GGA-PBE, GGA-PBEsol and GGA ＋ U. The effectiveness of the U for the structural properties as compared to other methods confirms the strong correlated nature of these compounds and the calculated lattice constants endorse the divalency of Yb. The results demonstrate the stable cubic CsCl structure of these compounds. Bulk modulus, Young＇s modulus, shear modulus, B/G ratio, Cauchy pressure, Poisson＇s ratio, anisotropic ratio,Kleinman parameters and Lame＇s coefficients were studied using the PBEsol to evaluate their importance in various types of engineering applications. The most prominent features of these compounds are their ductility, very high melting points, resistance to corrosion, and anisotropic nature.

关键词： strongly correlated electron systems Rare-earth monoaurides Mechanical properties Ab-initio calculation

Folding model calculations for ~6He+^(12)C elastic scattering

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Chinese Physics C 2016年第3期40卷 66-73页

作者： awad A.Ibraheem Physics Department King Khalid University Physics Department Al-Azhar University

In the framework of the double folding model, we used the α＋2n and di-triton configurations for the nuclear matter density of the ~6He nucleus to generate the real part of the optical potential for the system ~6He＋^（12）C. As an alternative, we also use the high energy approximation to generate the optical potential for the same system. The derived potentials are employed to analyze the elastic scattering differential cross section at energies of 38.3, 41.6 and 82.3 Me V/u. For the imaginary part of the potential we adopt the squared Woods-saxon form. The obtained results are compared with the corresponding measured data as well as with available results in the literature. The calculated total reaction cross sections are investigated and compared with the optical limit Glauber model description.

关键词： optical model elastic scattering halo nuclei folding model glauber model

Enhancing Network Intrusion Detection Model Using Machine Learning Algorithms

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Computers, Materials & Continua 2021年第4期67卷 979-990页

作者： Nancy awadallah awad Department of Computer and Information systems Sadat Academy for Management SciencesCairo11742Egypt

After the digital revolution,large quantities of data have been generated with time through various *** networks have made the process of data analysis very difficult by detecting attacks using suitable *** Intrusion Detection systems(IDss)secure resources against threats,they still face challenges in improving detection accuracy,reducing false alarm rates,and detecting the unknown *** paper presents a framework to integrate data mining classification algorithms and association rules to implement network intrusion *** experiments have been performed and evaluated to assess various machine learning classifiers based on the KDD99 intrusion *** study focuses on several data mining algorithms such as;naïve Bayes,decision trees,support vector machines,decision tables,k-nearest neighbor algorithms,and artificial neural ***,this paper is concerned with the association process in creating attack rules to identify those in the network audit data,by utilizing a KDD99 dataset anomaly *** focus is on false negative and false positive performance metrics to enhance the detection rate of the intrusion detection *** implemented experiments compare the results of each algorithm and demonstrate that the decision tree is the most powerful algorithm as it has the highest accuracy(0.992)and the lowest false positive rate(0.009).

关键词： Intrusion detection association rule data mining algorithms KDD99

Impact Assessment and Mitigation Techniques for High Penetration Levels of Renewable Energy sources in Distribution Networks:Voltage-control Perspective

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Journal of Modern Power systems and Clean Energy 2022年第2期10卷 450-458页

作者： Ahmed s.A.awad Dave Turcotte Tarek H.M.El-Fouly Natural Resources Canada Can-metENERGYVarennesCanadaon leave from the Electrical Power and Machines DepartmentFaculty of EngineeringAin Shams UniversityCairo 11566Egyp Natural Resources Canada CanmetENERGYVarennesCanada Advanced Power and Energy Center Khalifa UniversityAbu DhabiUnited Arab Emirates

The integration of renewable distributed generation(RDG)into distribution networks is promising and increasing ***,high penetration levels of distributed generation(DG)are often limited as they may have an adverse effect on the operation of distribution *** of the operation challenges is the interaction between DG and voltage-control equipment,e.g.,an under-load tap changer(ULTC),which is basically designed to compensate for voltage changes caused by slow load *** integration of variable DGs leads to rapid voltage fluctuations,which can negatively affect the tap operation of *** paper investigates the impact of high penetration levels of RDG on the tap operation of ULTC in distribution networks through *** mitigation techniques that can alleviate this impact are also *** these techniques,constant power-factor mode is regarded as the best trade-off between the simplicity and effectiveness of minimizing the number of tap *** are performed on a Canadian benchmark rural distribution feeder using OpenDss software.

关键词： Renewable energy distributed generation(DG) voltage regulator load tap changer distribution network.