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Optoelectronics Letters 2020年第5期16卷 369-372页

作者： S.Alsheikh Salo b.abdallah M.Akel M.Kakhia S.Alsheikh Salo B.AbdallahM.AkelM.Kakhia Department of PhysicsAtomic Energy CommissionDamascus P.O.Box 6091Syria1

The chromium(Cr)films on silicon Si(100)substrate are prepared using DC magnetron sputtering technique at an argon gas pressure of 3 Torr for different applied powers(40—140 W).The chemical composition,the thicknesses and the structural characterization of the deposited Cr films are studied and analyzed using energy dispersive X-ray spectroscopy(EDX),scanning electron microscopy(SEM),and X-ray diffraction(XRD),***,the generated plasma parameters,including floating potential,plasma potential,electron density,ion density and electron temperature,have been measured,and the automated Langmuir probe is used for the Cr films *** ion and metal fluxes are also *** results show that the Cr film thickness enhances with the higher applied *** Cr deposited films properties are characterized and correlated with the measured plasma parameters.

关键词： deposited chromium film

Evaluation of rainwater harvesting and shrub establishment methods for sustainable watershed management in northern Afghanistan

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Journal of Mountain Science 2022年第8期19卷 2346-2359页

作者： LOUHAICHI Mounir HASSAN Sawsan GAMOUN Mouldi SAFI Navin abdallah Mohamed A.b. ATES Serkan International Center for Agricultural Research in the Dry Areas(ICARDA) Tunis 1004Tunisia Department of Animal and Rangeland Sciences Oregon State UniversityCorvallisOR 97331USA International Center for Agricultural Research in the Dry Areas(ICARDA) Amman 11185Jordan Consultant-Field Assistant Mazar Sharif 1703Afghanistan

Watershed rangelands in Northern Afghanistan provide various ecosystem services that support the local people's livelihoods,but they are now highly degraded essentially due to the continuous high grazing pressure and recurrent *** of shrub establishment method enhanced by water harvesting techniques to rehabilitate degraded rangelands have not been well *** main goal of this study was to evaluate the impact of direct seeding and transplanting of seedlings in combination with semi-circular bunds on growth,yield,and survival rate of four shrub species(Atriplex halimus,Atriplex nummularia,Atriplex lentiformis,andMaireana brevifolia)under semi-arid conditions of Sayyad village,Khulm *** rate(%),plant height,width,and plant length(cm)and plant cover(%)were measured for each plant over five occasions.A non-destructive reference unit was used to estimate biomass *** results showed that growth attributes and biomass production of shrubs were consistently greater in the transplanting compared to direct *** average,the plant length,width,height,volume,cover,and biomass production of transplanted shrubs were greater than direct-seeded shrubs by 24.3%,8.6%,8.7%,121.5%,13.8% and 34.1%,*** production of transplanted seedlings was the highest for ***(1313.5 g DM/plant)and ***(800 g DM/plant).There was a strong correlation between plant biomass production and plant volume(R^(2)_(Plant volume)=0.88)for the shrub ***,indicating that plant volume is a key variable for assessing biomass production for this ***,the survival rate of *** was 100% in both planting methods,suggesting that based on better survival this halophytic plant has great potential when restoring degraded ***,on the basis of better growth rates,yield,and survival,transplanting *** *** may enhance shrub establishment and contribute to the rehabilitation of slop

关键词： biomass production Land degradation Rangeland rehabilitation Seed germination Shrub survival Vegetation cover Water harvesting

Reliable Phase Selection Method for Transmission Systems based on Relative Angles between Sequence Voltages

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1431-1444页

作者： abdallah A.Aboelnaga Maher A.Azzouz the Department of Electrical and Computer Engineer ing University of WindsorWindsorON N9B 3P4Canada Electrical Power and Machines Department Faculty of EngineeringAin Shams UniversityCairo 11566Egypt the Electrical Engineering Department Qatar UniversityDohaQatar

Fault currents emanating from inverter-based resources(IbRs)are controlled to follow specific references to support the power grid during ***,these fault currents differ from the typical fault currents fed by synchronous generators,resulting in an improper operation of conventional phase selection methods(PSMs).In this paper,the relative angles between sequence voltages measured at the relay location are determined analytically in two stages:(1)a short-circuit analysis is performed at the fault location to determine the relative angles between sequence voltages;and(2)an analysis of the impact of transmission line on the phase difference between the sequence voltages of relay and fault is conducted for different IbR ***,new PSM zones based on relative angles between sequence voltages are devised to facilitate accurate PSM regardless of the fault currents,resistances,or locations of *** time-domain simulations confirm the accuracy of the proposed PSM with different fault locations,resistances,types,and currents.

关键词： Fault resilience fault type identification phase selection method inverter-based resource control function renewable energy source sequence voltage

DECAY ESTIMATES FOR ISENTROPIC COMPRESSIbLE MAGNETOHYDRODYNAMIC EQUATIONS IN bOUNDED DOMAIN

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Acta Mathematica Scientia 2012年第6期32卷 2211-2220页

作者： Mohamed Ahmed abdallah 江飞谭忠 School of Mathematical Sciences Xiamen University College of Mathematics and Computer Science Fuzhou University Institute of Applied Physics and Computational Mathematics

In this paper, under the hypothesis that y is upper bounded, we construct a Lyapunov functional for the multidimensional isentropic compressible magnetohydrodynamic equations and show that the weak solutions decay exponentially to the equilibrium state in L2 norm. Our result verifies that the method of Daoyuan Fang, Ruizhao Zi and Ting Zhang I1] can be adapted to magnetohydrodynamic equations.

关键词： Navier-Stokes equations weak solution decay estimates magnetohydrody-namic

Daily variation of radon gas and its short-lived progeny concentration near ground level and estimation of aerosol residence time

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Chinese Physics b 2016年第5期25卷 111-118页

作者： M Mohery A M abdallah A Ali S S baz Physics Department Faculty of Science University of Jeddah Physics Department Faculty of Science Sohag University Astronomy Department Faculty of Science King Abdulaziz University Astronomy Department Faculty of Science Cairo University Physics Department Girls Faculty of Science King Abdulaziz University

Atmospheric concentrations of radon（^（222）Rn） gas and its short-lived progenies^（218）Po,^（214）Pb, and^（214）Po were continuously monitored every four hours at the ground level in Jeddah city, Kingdom of Saudi Arabia. The measurements were performed three times every week, starting from November 2014 to October 2015. A method of electrostatic precipitation of positively charged^（218）Po and ^（214）Po by a positive voltage was applied for determining^（222）Rn gas concentration. The short-lived^（222）Rn progeny concentration was determined by using a filter holder connected with the alpha-spectrometric technique. The meteorological parameters（relative air humidity, air temperature, and wind speed） were determined during the measurements of^（222）Rn and its progeny concentrations.^（222）Rn gas as well as its short-lived progeny concentration display a daily and seasonal variation with high values in the night and early morning hours as compared to low values at noon and in the afternoon. The observed monthly atmospheric concentrations showed a seasonal trend with the highest values in the autumn/winter season and the lowest values in the spring/summer season. Moreover, and in parallel with alphaspectrometric measurements, a single filter-holder was used to collect air samples. The deposited activities of^（214）Pb and the long-lived^（222）Rn daughter ^（210）Pb on the filter were measured with the gamma spectrometric technique. The measured activity concentrations of^（214）Pb by both techniques were found to be relatively equal largely. The highest mean seasonally activity concentrations of ^（210）Pb were observed in the autumn/winter season while the lowest mean were observed in the spring/summer season. The mean residence time（MRT） of aerosol particles in the atmospheric air could be estimated from the activity ratios of ^（210）Pb/^（214）Pb.

关键词： daily variation radon progeny concentration meteorological variables

ANALYZING TAX CREDITS FOR RESIDENTIAL ENERGY EFFICIENCY USING ENERGY MODELING

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Journal of Green building 2018年第1期13卷 83-94页

作者： Caroline M.Clevenger Moatassem abdallah Jayapradha Madhavan Construction Engineering and Management College of Engineering&Applied ScienceUniversity of Colorado Denver1200 Larimer StreetDenverCO USA

From roughly 2013 to 2016,ten building product categories related to residential energy efficiency were eligible for United States ENERGY STAR Federal Tax *** general,the objective of residential energy-efficiency tax credits is to encourage individuals to increase residential energy-efficiency investments and invest in properties that generate renewable *** research analyses eight of the available tax credit categories for four climatic zones and recommends packages based on low Life Cycle Cost and low First Cost for the eligible ENERGY STAR *** experiment was conducted using energy modeling software for different tax credits and costs combinations,to explore potential variability in economic impact of the federal *** used building America b10 benchmark as a reference,and the energy computations were completed using building Energy Optimization(bEopt)*** suggest that ENERGY STAR product packages that include PV systems generally have the lowest(best)Life Cycle Costs and packages that include Geothermal Heat Pumps generally have the highest(worst)Life Cycle ***,there are tradeoffs between cost savings and energy source savings,and the particular economics of tax incentives for ENERGY STAR products depend on project specifics as well as owner priorities.

关键词： ENERGY STAR products energy performance lifecycle costs

Information theoretic conditions for tracking in leader-follower systems with communication constraints

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控制理论与应用（英文版） 2013年第3期11卷 376-385页

作者： Yongxiang RUAN Sudharman K.JAYAWEERA Chaouki T.abdallah Department of Electrical and Computer Engineering University of New Mexico

In this paper, we introduce a general framework for tracking in leader-follower systems under communication constraints, in which the leader and follower systems as well as the corresponding controllers are spatially distributed and connected over communication links. We provide necessary conditions on the channel data rate of each communication link for tracking of the leader-follower systems. by considering the forward and feedback channels as one cascade channel, we also provide a lower bound for the data rate of the cascade channel for the system to track a reference signal such that the tracking error has finite second moment. Examples and simulations are provided to demonstrate some of the results.

关键词： Networked control systems Leader-follower systems Information theory

A Shuffling-Steganography Algorithm to Protect Data of Drone Applications

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Computers, Materials & Continua 2024年第11期81卷 2727-2751页

作者： Ahamad b.Alkodre Nour Mahmoud bahbouh Sandra Sendra Adnan Ahmed Abi Sen Yazed Alsaawy Saad Said Alqahtany abdallah Namoun Hani Almoamari Faculty of Computer and Information Systems Islamic UniversityAl-Madinah42351Saudi Arabia Department of Information and Communication Sciences Granada UniversityGranada18071Spain Instituto de Investigación para la Gestión Integrada de Zonas Costeras Universitat Politècnica de ValènciaValencia46730Spain Department of Graduate Studies&Scientific Research University of Prince MugrinAl-Madinah42351Saudi Arabia

In Saudi Arabia,drones are increasingly used in different sensitive domains like military,health,and agriculture to name a ***,drone cameras capture aerial images of objects and convert them into crucial data,alongside collecting data from distributed sensors supplemented by location *** interception of the data sent from the drone to the station can lead to substantial *** address this issue,highly confidential protection methods must be *** paper introduces a novel steganography approach called the Shuffling Steganography Approach(SSA).SSA encompasses five fundamental stages and three proposed algorithms,designed to enhance security through strategic encryption and data hiding ***,this method introduces advanced resistance to brute force attacks by employing predefined patterns across a wide array of images,complicating unauthorized *** initial stage involves encryption,dividing,and disassembling the encrypted data.A small portion of the encrypted data is concealed within the text(Algorithm 1)in the third ***,the parts are merged and mixed(Algorithm 2),and finally,the composed text is hidden within an image(Algorithm 3).Through meticulous investigation and comparative analysis with existing methodologies,the proposed approach demonstrates superiority across various pertinent criteria,including robustness,secret message size capacity,resistance to multiple attacks,and multilingual support.

关键词： Health of palm trees steganography based text steganography based image drone fog computing security

The utility of X-Ray fluorescence spectrometry as a tool for monitoring compliance with limits on concentrations of halogenated flame retardants in waste polymers:A critical review

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Emerging Contaminants 2022年第1期8卷 9-20页

作者： Misbah Alghamdi Mohamed Abou-Elwafa abdallah Stuart Harrad School of Geography Earthand Environmental SciencesUniversity of BirminghamBirminghamB152TTUK

This study reviews current knowledge about the presence of brominated and chlorinated organophosphate flame retardants(bFRs and Cl-OPFRs)in plastic consumer articles,with particular reference to the potential as a result of recycling,for such chemicals to unintentionally contaminate articles in which flame retardants are not *** minimize such unintentional contamination,jurisdictions such as the EU(European Union)have introduced limits on concentrations of some bFRs in waste plastics,with articles exceeding such limits prevented from being *** technical and economic constraints associated with the conventional methods for determining compliance with such limit values exist,leading to less specific,but simpler,more rapid,and less expensive methods such as portable X-ray fluorescence(XRF)spectrometry being identified as possible *** paper thus examines the evidence that XRF offers a viable method for checking compliance with existing and possible future limits on bFRs and Cl-OPFRs in waste plastics and identifies future research priorities.

关键词： Waste plastics Low POP concentration limits PbDEs HbCDD Chlorinated organophosphate esters XRF screening

Pion emission in α-particle interactions with various targets of nuclear emulsion detector

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Chinese Physics C 2015年第9期39卷 35-42页

作者： A.Abdelsalam Z.Abou-Moussa N.Rashed b.M.badawy H.A.Amer W.Osman M.M.El-Ashmawy N.abdallah Physics Department Faculty of Science Cairo University Mohamed El-Nadi High Energy Lab Faculty of Science Cairo University Physics Department Faculty of Science Fayoum University Reactor Physics Department Nuclear Research Center Atomic Energy Authority Nuclear and Radiological Regulatory Authority NRRA

The behavior of relativistic hadron multiplicity for 4He-nucleus interactions is investigated. The experi- ment is carried out at 2.1 A and 3.7 A GeV （Dubna energy） to search for the incident energy effect on the interactions inside different emulsion target nuclei. Data are presented in terms of the number of emitted relativistic hadrons in both forward and backward angular zones. The dependence on the target size is presented. For this purpose the statistical events are discriminated into groups according to the interactions with H, CNO, Em, and Agbr target nuclei. The separation of events, into the mentioned groups, is executed based on Glauber＇s multiple scattering theory approach. Features suggestive of a decay mechanism seem to be a characteristic of the backward emission of relativistic hadrons. The results strongly support the assumption that the relativistic hadrons may already be emitted during the de-excitation of the excited target nucleus, in a behavior like that of compound-nucleus disintegration. Regarding the limiting fragmentation hypothesis beyond 1 A GeV, the target size is the main parameter affecting the backward production of the relativistic hadron. The incident energy is a principal factor responsible for the forward relativistic hadron production, implying that this system of particle production is a creation system. However, the target size is an effective parameter as well as the projectile size considering the geometrical concept regarded in the nuclear fireball model. The data are analyzed in the framework of the FRITIOF model.

关键词： α-particle interactions at Dubna energies shower particle sources target size dependence FRITIOFmodel