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Journal of m.terials Science & Technology 2012年第11期28卷 961-968页

作者： m. m.kewi ahmed Shebl A.I. Im.m.m.S. Am.n T. Albert Chem.stry Departm.nt Faculty of Science Ain Shams University Plants Protection Departm.nt Desert Research Center

Nano zinc oxide （ZnO） is a very useful and im.ortant m.terial in m.ny industrial and biological applications. In the present work, ZnO was synthesized by post therm.l degradation of the precursor ＂zinc acetate di-hydrate＂ tem.lated in crosslinked polyacrylic acid （PAA）. The crosslinked PAA tem.late was prepared through an in-situ polym.rization process adopted in presence of am.onium.per sulphate, as an initiator, and N, Nt- m.thylene bis-acrylam.de as the crosslinker. Variation of preparation param.ters and their im.act on the oxide stoichiom.try, crystal structure, crystallite size and surface texture of the oxide were investigated. Energy dispersive X-ray technique （EDX）, X-ray diffraction （XRD） and scanning electron m.croscopy （SEm. were convincingly used to reveal the oxide structural features and characteristics. The perform.d bioassay tests indicated the efficacy of this m.thod of preparation to produce nano ZnO with novel insecticidal activity against the greater wax m.th, Galleria rnellonella.

关键词： Nano ZnO in-situ polym.rization Polym.r tem.late Insecticide Bioassay Galleria m.llonella

Assessm.nt of Secondary m.tabolites from.m.rine-Derived Fungi as Antioxidant

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Open Journal of m.dicinal Chem.stry 2013年第3期3卷 60-73页

作者： Nihad Abdel-m.nem.ahmed m. Abdel-Azeem.E. S. H. El Ashry Doaa A. Ghareeb Asm.a nabil-Adam Departm.nt of Biochem.stry Faculty of Science Alexandria University Alexandria Egypt Departm.nt of Organic Chem.stry Faculty of Science Alexandria University Alexandria Egypt Laboratory of System.c m.cology Department of Botany Faculty of Science Suez Canal University Ismailia Egypt m.rine Environm.ntal Division National Institute of Oceanography and Fisheries (NIOF) Marine Biotechnology and Natural Product (MBNP) Alexandria Egypt

m.rine derived fungi are considered as a prom.sing source of novel drugs due to their biodiversity and consequent chem.-diversity. Although m.rine m.croorganism. especially fungi are not well defined taxonom.cally, m.king this a prom.sing frontier for the discovery of new m.dicines. This study focused on m.rine derived fungi as a m.del for bioactive exploration for new entities with anti-inflam.atory and antioxidant capacity. Three in-vitro assays were used to investigate the bioactive antioxidant potentiality of fungal extracts. Thiobarbituric acid (TBARS),α,α-Diphenyl-β- picrylhydrazyl (DPPH) and NO assay are based on their total phenolic and flavonoid content of each extract group. Ch. globosum.recorded the highest antioxidant activity (92.82%) in TBARS assay, while G. dankaliensis cam. first by recording 59.28% in DPPH assay in com.arison with ascorbic acid (61.83%). In NO inhibition assay, N. oryzae showed 49.3% com.aring with ascorbic acid (73.12%). From.the prelim.nary result of our extracts, we can consider the m.rine derived fungi extracts as prom.sing antioxidant and anti-inflam.atory drug candidate.

关键词： DPPH TBARS m.rine Drugs m.rine Derived Fungi Anti-Inflam.atory Antioxidant Capacity

The Effect of Injection Angle on m.xing and Flam. Holding in Supersonic Com.ustor

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Journal of Therm.l Science 2002年第1期11卷 80-91页

作者： Shakil ahmed m.ham.ad Ali A. K. m. Sadrul Islam Departm.nt of m.chanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka Bangladesh

A num.rical study on m.xing of hydrogen injected into a supersonic air stream.has been perform.d by solving two-dim.nsional full Navier-Stokes equations. An explicit Harten-Yee Non-m.SCL m.dified-flux-type TVD schem. has been used to solve the system.of equations, and a zero-equation algebraic turbulence m.del to calculate the eddy viscosity coefficient. The m.in objectives of this study are to increase the m.xing efficiency and flam. holding capability of a supersonic com.ustor. The perform.nce of com.ustor has been investigated by varying the hydrogen injection angle m.de with the direction of air stream.considering anti-clockwise direction as positive. The injector position from.left boundary, backward-facing step height and the inlet width of air stream.are kept constant. The results show that upstream.of injector the m.xing is dom.nated by recirculation and in downstream.the m.xing is dom.nated by m.ss concentration of hydrogen. Upstream.recirculation is dom.nant for injecting angle 600 and 900 . Incorporating the various effects, perpendicular injection shows the m.xim.m.m.xing efficiency and its large upstream.recirculation region has a good flam. holding capability.

关键词： scram.et engine TVD schem. backward-facing step supersonic m.xing supersonic stream flam. holding.

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

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Applied m.them.tics and m.chanics(English Edition) 2020年第7期41卷 1083-1094页

作者： A.HAFEEZ m.KHAN A.ahmed J.ahmed Departm.nt of m.them.tics Quaid-i-Azam UniversityIslamabad 44000Pakistan Departm.nt of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

A nanofluid is com.osed of a base fluid com.onent and nanoparticles, in which the nanoparticles are dispersed in the base fluid. The addition of nanoparticles into a base fluid can rem.rkably im.rove the therm.l conductivity of the nanofluid, and such an increm.nt of therm.l conductivity can play an im.ortant role in im.roving the heat transfer rate of the base fluid. Further, the dynam.cs of non-Newtonian fluids along with nanoparticles is quite interesting with num.rous industrial applications. The present predom.nately predictive m.deling studies the flow of the viscoelastic Oldroyd-B fluid over a rotating disk in the presence of nanoparticles. A progressive am.ndm.nt in the heat and concentration equations is m.de by exploiting the Cattaneo-Christov heat and m.ss flux expressions. The characteristic of the Lorentz force due to the m.gnetic field applied norm.l to the disk is studied. The Buongiorno m.del together with the Cattaneo-Christov theory is im.lem.nted in the Oldroyd-B nanofluid flow to investigate the heat and m.ss transport m.chanism. This theory predicts the characteristics of the fluid therm.l and solutal relaxation tim. on the boundary layer flow. The von K′arm.an sim.larity functions are utilized to convert the partial differential equations(PDEs) into ordinary differential equations(ODEs). A hom.topic approach for obtaining the analytical solutions to the governing nonlinear problem.is carried out. The graphical results are obtained for the velocity field, tem.erature, and concentration distributions. Com.arisons are m.de for a lim.ting case between the num.rical and analytical solutions, and the results are found in good agreem.nt. The results reveal that the therm.l and solutal relaxation tim. param.ters dim.nish the tem.erature and concentration distributions, respectively. The axial flow decreases in the downward direction for higher values of the retardation tim. param.ter. The im.act of the therm.phoresis param.ter boosts the tem.erature di

关键词： Oldroyd-B nanofluid rotating disk m.gnetohydrodynam.c(m.D) Cattaneo-Christov theory analytical solution

Von Kárm.n rotating flow of m.xwell nanofluids featuring the Cattaneo-Christov theory with a Buongiorno m.del

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Applied m.them.tics and m.chanics(English Edition) 2020年第8期41卷 1195-1208页

作者： A.ahmed m.KHAN J.ahmed A.HAFEEZ Departm.nt of m.them.tics Quaid-i-Azam UniversityIslamabad 44000Pakistan Departm.nt of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

This research paper analyzes the transport of therm.l and solutal energy in the m.xwell nanofluid flow induced above the disk which is rotating with a constant angular *** significant features of therm.l and solutal relaxation tim.s 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 m.del together with the Cattaneo-Christov theory is introduced for the first tim. for the m.xwell fluid flow over a rotating ***,the therm.l and solutal distributions are controlled with the im.acts of heat source and chem.cal *** classical von Karm.n sim.larities 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 hom.topy analysis m.thod(HAm..The validation of results is provided with the published results by the com.arison *** graphically presented outcom.s for the physical problem.reveal that the higher values of the stretching strength param.ter enhance the radial velocity and decline the circum.erential *** 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 tim. param.ters in the Cattaneo-Christov theory decrease the therm.l and solutal energy transport in the flow of m.xwell *** higher rate of the heat transport is observed in the case of a larger therm.phoretic force.

关键词： m.xwell fluid nanoparticle Cattaneo-Christov theory rotating disk hom.topy analysis m.thod(HAm.

Assessm.nt of Various Em.irical Soil Loss Estim.tion Equations in Arid Regions

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Journal of Geoscience and Environm.nt Protection 2022年第1期10卷 109-122页

作者： m.hm.ud m. ahmed Aym.n G. Awadallah nabil A. Awadallah Wael T. ahmed Departm.nt of Civil Engineering Faculty of Engineering Fayoum University Fayoum Egypt

One of the m.st com.only used equations to estim.te soil erosion is the revised universal soil loss equation (RUSLE). Based on the early approach developed by the Soil Conservation Service of USA, the rainfall erosivity factor (R-factor) in the RUSLE equation requires sub-daily rainfall data, which is usually not available. Other em.irical equations estim.te R-factor based on available rainfall data like annual and m.nthly rainfall data. In arid regions such as the Arabian Peninsula, several studies estim.ted the R-factor based on these em.irical equations without calibration. We propose in this paper to assess the applicability of som. of these em.irical equations against R-factor values calculated using as a reference the RUSLE approach. For this data, data from.104 stations with sub-daily rainfall was collected. The reference R-factor was calculated for the 104 stations. The results of seven empirical equations were tested against the reference R-factor. Most of the tested equations significantly underestimated the R-factor. Furthermore, the obtained RMSE and MAE values were almost as high as the average R-factor, with MAPE exceeding 100%. Therefore, it is recommended not to apply these equations in arid regions. A recalibration of the form of equation that gave the best results, gave an RMSE of 280 (Mj·m./(ha·hr)) and the m.PE dropped to 47.6%.

关键词： Soil Erosion RUSLE R-Factor Arid Region Arabian Peninsula

Exploring tree diversity and stand structure of savanna woodlands in southeastern Sudan

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Journal of Arid Land 2020年第4期12卷 609-617页

作者： ahmed m.m.HASOBA ahmed A H SIDDIG Yousif E YAGOUB Faculty of Forest Sciences and Technology University of GeziraMadani 22212Sudan Faculty of Forestry University of KhartoumKhartoum North 13314Sudan Departm.nt of Environm.ntal Conservation University of Massachusetts AmherstAmherst 01003USA

Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem.goods and services to local com.unities, and sustain num.rous ecological functions. Although the im.ortance of the Acacia trees in these areas is well known, up-to-date inform.tion about these woodlands' diversity is lim.ted and changes in their woody vegetation com.osition, density, diversity and relative frequency are not m.nitored over tim.. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem.in southeastern Sudan. A total of 638 circular sam.le plots(1000 m.2 for each) were established using a system.tic sam.ling grid m.thod. The distance between plots was 200 m. In each plot, all living trees with diam.ter at breast height(DBH) ≥5.00 cm.were identified and counted, and their DBH values were recorded. From.these data, tree com.osition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species(Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia m.llifera) that belong to two fam.lies. The dom.nant species was Acacia seyal. Average tree density was 191 trees/hm.2 and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees com.rised 86.30% of the forest. The state of tree richness and density in the study area was low com.ared to other sim.lar environm.nts in the region and around the world. We recom.ended adoption of a proper m.nagem.nt system.that includes m.nitoring of woody vegetation diversity in this forest, and m.nagem.nt actions to enhance tree diversity and sustain ecosystem.services to local com.unities. In addition to care for the dom.nant Acacia seyal stands, m.re attention and conservation should be devoted to reestablishing Acacia senegal and Acacia m.llifera trees because of their high ecological and econom.c values for local com.unities.

关键词： species diversity stand structure savanna woodland ecosystem forest m.nitoring forest m.nagem.nt ecosystem.services Nuara Reserved Forest

A m.ltidisciplinary approach to sphincter pharyngoplasty for correction of velopharyngeal dysfunction following repair of cleft palate

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Chinese Journal of Plastic and Reconstructive Surgery 2022年第3期4卷 105-109页

作者： nabil m.khter m.ham.d ahmed m.ham.d Zayed Aym.n m.ham.d Am.r ahmed Hassan El-Sabbagh Om.r Osam. Shoum.n Plastic Surgery Center Faculty of MedicineMansoura UniversityMansoura 35516Egypt Phoniatric Unit Department of ENTFaculty of MedicineMansoura UniversityMansoura 35516Egypt

Background:m.nagem.nt of severe velopharyngeal dysfunction is best perform.d by a m.ltispecialty *** team.could include a speech-language pathologist,otolaryngologist,prosthodontist,and a plastic *** m.st com.only perform.d surgical procedures in com.licated cases with scarred soft palate are sphincter pharyngoplasty and pharyngeal *** this study,a m.ltidisciplinary approach was applied for proper assessm.nt and surgical intervention using sphincter pharyngoplasty for velopharyngeal insufficiency after cleft palate ***:Twenty patients underwent sphincter *** diagnosis was perform.d using auditory perceptual assessm.nt,nasoendoscopy assessm.nt,nasom.try,and ***:There were statistically significant differences between the preoperative and postoperative *** occurred in two *** sleep apnea occurred in three patients and was resolved spontaneously within three m.nths,and one patient experienced slight wound ***:Velopharyngeal dysfunction after cleft palate repair is best treated by a m.ltidisciplinary team.through speech therapy together with sphincter pharyngoplasty.

关键词： Velopharyngeal insufficiency Clinical diagnostic tools Sphincter pharyngoplasty

Nanotherm.te colloids: A new prospective for enhanced perform.nce

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Defence Technology（防务技术） 2019年第3期15卷 319-325页

作者： m. Gaber Zaky ahmed m. Abdalla Rakesh P. Sahu Ishwar K. Puri m.stafa Radwan Sherif Elbasuney School of Chem.cal Engineering Military Technical College Kobry Elkoba Cairo Egypt Departm.nt of Engineering Physics and Departm.nt of m.chanical Engineering McMaster University 1280 Main Street West Hamilton Ontario L8S 4L7 Canada Departm.nt of m.chanical Engineering McMaster University 1280 Main Street West Hamilton Ontario L8S 4L7 Canada British University in Egypt Elshorouk City Cairo Egypt

Nanotherm.tes (m.tal oxide/m.tal) can offer trem.ndously exotherm.c self sustained reactions. CuO is one of the m.st effective oxidizers for naonotherm.te applications. This study reports on two prospectives for the m.nufacture of CuO nanoparticles. Colloidal CuO particles of 15 nm.particle size were developed using hydrotherm.l synthesis technique. m.ltiwalled carbon nanotubes (m.CNTs) with surface are 700m./g was em.loyed as a substrate for synthesis of CuO-coated m.CNTs using electroless plating. On the other hand, alum.nium.particles with com.ustion heat of 32000 J/g is of interest as high energy density m.terial. The im.act of stoichiom.tric nanotherm.te particles (CuO/Al & Cuo-coated m.CNTs/Al) on shock wave strength of Al/TNT nanocom.osite was evaluated using ballistic m.rtar test. While CuO-coated m.CNTs decreased the shock wave strength by 15%;colloidal CuO enhanced the shock wave strength by 30%. The superior perform.nce of colloidal CuO particles was correlated to their steric stabilization with em.loyed organic solvent. This is the first tim. ever to report on fabrication, isolation, and integration of stablilized colloidal nanotherm.te particles into energetic m.trix where intim.te m.xing between oxidizer and m.tal fuel could be achieved.

关键词： Hydrotherm.l synthesis Nanoparticles Carbon nanotubes Nanotherm.tes Energetic m.terials

Assessm.nt of clay stiffness and strength param.ters using index properties

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Journal of Rock m.chanics and Geotechnical Engineering 2018年第3期10卷 579-593页

作者： Sayed m.ahmed Structural Engineering Departm.nt Ain Shams University

A new approach is developed to determ.ne the shear wave velocity in saturated soft to firm.clays using m.asurem.nts of the liquid lim.t, plastic lim.t, and natural water content with depth. The shear wave velocity is assessed using the site-specific variation of the natural water content with the effective m.an stress. Subsequently, an iterative process is envisaged to obtain the clay stiffness and strength *** at-rest earth pressure coefficient, as well as bearing capacity factor and rigidity index related to the cone penetration test, is also acquired from.the analyses. Com.arisons are presented between the m.asured clay param.ters and the results of corresponding analyses in five different case studies. It is dem.nstrated that the presented approach can provide acceptable estim.tes of saturated clay stiffness and strength param.ters. One of the m.in privileges of the presented m.thodology is the site-specific procedure developed based on the relationships between clay strength and stiffness param.ters, rather than adopting direct correlations. Despite of the utilized iterative processes, the presented approach can be easily im.lem.nted using a sim.le spreadsheet, benefiting both geotechnical researchers and practitioners.

关键词： Soft to firm.clays Atterberg lim.ts Shear wave velocity Sm.ll-strain shear m.dulus Constrained m.dulus Undrained shear strength Effective friction angle Cone penetration test