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experimental approaches and analytical technique for determining heavy metals in fallen dust at ferrosilicon production factory in edfu, Aswan,egypt

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2005年第8期6卷 708-718页

作者： SOLTAn m.e rageh h.m.rageh n.m.ahmed m.e Department of Chemistry Faculty of Science at Aswan South Valley UniversityEgypt Department of Chemistry Faculty of Science at Qena South Valley UniversityEgyptDepartment of Chemistry Faculty of Science at Qena South Valley UniversityEgyptDepartment of Environment Egyptian Ferroalloy Edfu AswanEgypt

In this study aimed to evaluate the pollution extent of metals and nonmetals inside and outside the ferrosilicon production factory in edfu, Aswan, egypt, raw materials (quartz, cokes, iron oxides), ferrosilicon alloy, silica fume, dust and suspended dust (at different sites) samples were collected from the factory, and fallen dust samples were collected from outside the factory, horizontally (at different sites and different distance and directions) and vertically (at different floors in the selected buildings). Gravimetric methods, X-ray fluorescence (XRF), flame photometer, wide range carbon determinator and atomic absorption spectroscopy tools were used for elements determination. The results indicating that the fallen dust and its element contents on southern factory walls being higher than those on eastern factory walls may be due to the nature of the dusts and effects of wind force and wind direction. Fallen dust levels in different regions outside the factory were found to be affected by the distance, direction and floors. The nature of dust samples was affected by gravity and the suspended dust in different factory units depended on the work capacity and method of handling materials by personnel in different production units. Silica fume was a complicated problem, had dangerous effect against the workers' health, and was characterized by high concentrations of SiO2(90.6%～93.6%) and heavy metals (mn, 420.6×10-6～520.3×10-6; Fe, 2354×10-6～2685×10-6; Co, 80.7×10-6～101.6×10 6 and ni,5.3× 10-6～6.05× 10-6). The TSP (Total Suspended Particulate) levels in all factory units were higher than the recom.ended air quality value (70 μg/m3) under egyptian law. The effect of ferrosilicon factory fallen dust on the surrounding regions decreased with increasing distance between the factory and these regions. The suspended dust samples in the factory units and their components greatly exceeded national and international standards, so health and environmental criteria must be

关键词： Air pollution Dust heavy metals Fallen dust

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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 Department of environmental Conservation University of Massachusetts AmherstAmherst 01003USA

Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. 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 sample plots(1000 m^2 for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height(DBh) ≥5.00 cm were identified and counted, and their DBh values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species(Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant 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 comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recom.ended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.

关键词： species diversity stand structure savanna woodland ecosystem forest monitoring forest management ecosystem services nuara Reserved Forest

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exploitation of the antibacterial,antibiofilm and antioxidant activities of Salvadora Persica(miswak)extract

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Journal of Bioresources and Bioproducts 2023年第1期8卷 59-65页

作者： Gamal m.el-Sherbiny ahmed mohamed Gazelly moham.ed h.Sharaf Saad A.moghannemm Shehata m.e mahmoud K.A.Ismail Ahmad S.el-hawary Botany and microbiology Department Faculty of Science(Boys)Al-Azhar UniversityCairo 11884Egypt

The Salvadora persica(***)*** stick,usually known as miswak,is still being em-ployed as an oral hygiene agent for plaque and gingivitis *** study aims to assess the antibacterial,antibiofilm,antioxidant,and phytochemical profile of *** *** ***-sica was purchased from a local market,grinded and extracted with petroleum *** disk dif-fusion,microdilution,and micro-plate assays were performed to evaluate the antibacterial and an-tibiofilm activities of the prepared extract at different concentrations against𝛽-lactam resistance Streptococcus *** radical scavenging 2,2-diphenyl-1-picrylhydrazyl(DPPh)and stable radical cationic chromophore,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate)(ABTS)methods were used to determine their antioxidant *** and spectrometric analyses were performed using gas chromatography-mass(GC-mS)*** minimum inhibitory concentration(mIC)of *** extract against𝛽-lactam resistance Streptococcus species ranged from 6.25 to 12.5 mg/*** maximum suppression of biofilm formation by *** extract was observed at mIC with a percentage of 68.66%,against Streptococcus *** *** ex-tract exhibited antioxidant activity with IC 50 of 20μg/mL and 35μg/mL from DPPh and ABTS,*** phytochemical characterization showed the presence of 22 compounds with ma-jor compounds;benzyl isothiocyanate(36.21%)and n-hexadecanoic acid(27.62%).The *** extract exhibited antibacterial activity against𝛽-lactam resistant Streptococcus species,showing a promising natural alternative that could be a treatment option.

关键词： β-lactam resistance Streptococcus species S.persica extract Antibacterial Antibiofilm Antioxidant GC-mS analysis

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Phase analysis of AlFe2B2 by synchrotron X-ray diffraction,magnetic and m?ssbauer studies

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Progress in natural Science:materials International 2017年第2期27卷 251-256页

作者： Tahir Ali m.n.Khan e.ahmed Asad Ali Physics Division Pakistan Institute of Nuclear Science and technology Department of Physics Abdul Wali Khan University PInSAT Preston University

The structural and magnetic properties of essentially phase pure AlFe2B2prepared by arc melting were compared with a sample containing impurities. Analysis was carried out by means of synchrotron X-ray diffraction, magnetic measurements and m?ssbauer spectroscopy. The analysis of synchrotron X-ray diffraction data confirmed the orthorhombic structure of space group Cmmm for AlFe2B2with Al13Fe4as main impurity phase. The magnetic measurements revealed an unsaturated ferromagnetic state in AlFe2B2with a transition tem.erature（Tc） of 286 K. Isothermal magnetization measurment at 5 K gave a saturation magnetization of 0.7 μB per Fe atom while Arrott plots establish the second order nature of ferromagnetic transition. The thermal evolution of m?ssbauer spectra confirmed the ferromagnetic nature of this material revealing an hyperfine field of 73 kOe and an isomer shift of 0.46 mm/s at 100 K. The m?ssbauer spectra of a phase pure sample was compared with the one containing impurity phases. It is suggested that the low tem.erature paramagnetic contribution in m?ssbauer spectra of phase pure material may have its origin in some intrinsic phenomena arising from defects or inhomogeneities in crystal structure.

关键词： AlFe2B2 Synchrotron X-ray diffraction Ferromagnetism mossbauer effect spectroscopy

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enhanced photocatalytic activity of Ce-doped ZnO nanopowders synthesized by combustion method

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Journal of Rare earths 2015年第3期33卷 255-262页

作者： m.Ahmad e.ahmed Fezza Zafar n.R.Khalid n.A.niaz Abdul hafeez m.Ikram m.Ajmal Khan 洪樟连 Department of Physics Bahauddin Zakariya University State Key Laboratory of Silicon materials Department of Materials Science & Engineering Zhejiang University Science and Technology Division University of Education

Facile and fast combustion method was used to synthesize Zn O and Ce-doped Zn O（CZO） nanocrystalline powders photocatalysts with different cerium concentrations（0.5 wt.%–10.0 wt.%） followed by calcination at 700 oC for 3 h. The prepared samples were characterized by a variety of characterization techniques such as X-ray diffraction（XRD）, scanning electron microscopy（Sem） combined with energy dispersive X-ray diffraction（eDX）, transmission electron microscopy（Tem）, UV-visible spectroscopy, BeT surface area analyser and photoluminescence spectroscopy（PL）, to study the crystal structure, surface morphology, chemical composition and optical properties. It was observed from XRD results that synthesized powders had hexagonal wurtzite structure with the smallest crystallite size about 13 nm. Absorption spectra showed that cerium doping enhanced the light absorption properties towards the visible light region. Photoluminescence spectra for Ce-doped Zn O samples exhibited relatively weak near band edge（nBe） emission peaks as compared to that of pristine Zn O. The photocatalytic activities of the prepared samples were evaluated by photocatalytic degradation of Rhodamine B（Rh B） under UV light and visible light（λ≥420 nm） irradiation. The textile mill effluent containing organic matters was also treated under sunlight using photocatalysis and the reduction in the chemical oxygen demand（COD） of the treated effluent revealed a complete destruction of the organic molecules along with colour removal. The results showed that the CZO photocatalyst doped with 3.0 wt.% cerium.exhibited four times enhanced photocatalytic activity compared to pure Zn O. The enhanced photocatalytic activity could be attributed to extended visible light absorption and inhibition of the electron-hole pair＇s recombination.

关键词： ZnO cerium combustion photocatalyst Rhodamine B rare earths

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The effect of fractional therm.elasticity on a two-dimensional problem of a mode I crack in a rotating fiber-reinforced therm.elastic medium

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Chinese Physics B 2013年第10期22卷 575-582页

作者： ahmed e.Abouelregal Ashraf m.Zenkour Department of mathematics Faculty of ScienceMansoura University Department of mathematics Faculty of ScienceKing Abdulaziz University Department of mathematics College of Science and ArtsUniversity of Aljouf Department of mathematics Faculty of ScienceKafrelsheikh University

This article is concerned with the effect of rotation on the general model of the equations of the generalized therm.e- lasticity for a homogeneous isotropic elastic half-space solid, whose surface is subjected to a mode-I crack problem. The fractional order theory of therm.elasticity is used to obtain the analytical solutions for displacement components, force stresses, and tem.erature. The boundary of the crack is subjected to a prescribed stress distribution and tem.erature. The normal mode analysis technique is used to solve the resulting non-dimensional coupled governing equations of the problem. The variations of the considered variables with the horizontal distance are illustrated graphically. Some particular cases are also discussed in the context of the problem. effects of the fractional parameter, reinforcement, and rotation on the varia- tions of different field quantities inside the elastic medium are analyzed graphically. Comparisons are made between the results in the presence and those in the absence of fiber-reinforcing, rotating and fractional parameters.

关键词： fiber-reinforced mode-I crack fractional order therm.elasticity theory rotating medium normalmode analysis

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Ion-acoustic waves at the night side of Titan's ionosphere:higher-order approximation

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Communications in Theoretical Physics 2020年第5期72卷 70-77页

作者： S m ahmed e R hassib U m Abdelsalam R e Tolba W m moslem Department of mathematics Faculty of ScienceSuez UniversitySuezEgypt Department of mathematics Faculty of ScienceFayoum UniversityFayoumEgypt Department of mathematics Rustaq College of EducationOman Centre for Theoretical Physics The British University in Egypt(BUE)El-Shorouk CityCairoEgypt Department of Physics Faculty of SciencePort Said UniversityPort Said 42521Egypt

nonlinear solitary waves are investigated for a plasma system at the night side of Titan's *** plasma model consists of three positive ions,namely C2h5^+,hCnh^+,and C3h5^+,as well as maxwellian *** basic set of fluid equations is reduced to a Korteweg de-Vries(KdV)equation and linear inhomogeneous higher order KdV(LIhO-KdV)*** solitary wave solutions of both equations are obtained using a renormalization *** solitary waves'existence region and the wave profile are investigated,and their dependences on the plasma parameters at the night side of Titan's ionosphere are *** solitary waves'phase velocities are subsonic or supersonic,and the propagating pulses are usually *** effect of higher-order corrections on the perturbation theory is *** is found that the higher-order contribution makes the amplitude slightly taller,which is suitable for describing the solitary waves when the amplitude augments.

关键词： plasmas ion-acoustic waves planets and satellites:atmospheres

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experimental validation of double-fed induction generator in oscillating water column using circulatory system-based optimization

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Clean energy 2024年第2期8卷 127-143页

作者： Basem.e.elnaghi ahmed m.Ismaiel Fathy el Sayed Abdel-Kader Reham h.moham.ed m.n.Abelwhab electrical Power and machine Department Suez Canal UniversityIsmailiaEgypt electrical Power and machine Department Menoufia UniversityMenoufiaEgypt Computer and Control Department Suez Canal UniversityIsmailiaEgypt

This paper validates the optimal operation for a grid-connected double-fed induction generator(DFIG)in an oscillating water column power plant(OWCPP).This study presents a novel optimization technique called the circulatory system-based optimization(CSBO)approach to develop six adaptive fuzzy logic controllers(AFLCs)with 30 parameters and compare them to chaotic-billiards optimization(C-BO)and genetic algorithm(GA).The proposed controller is also compared with a proportional-integral differential(PID)controller based on a self-adaptive global-best harmony search(SGhS).CSBO-based AFLCs are fully investigated under different scenarios and experimented with using a real-time interface *** results of using CSBO-AFLCs revealed a fast time response,fast convergence,less overshoot and minimal error compared with those achieved with C-BO-AFLC,SGhS-PID and GA-AFLC during different case *** CSBO-based AFLCs ensure maximum power from the DFIG in an OWCPP and enhance dynamic response with very low *** results show that the CSBO shows better power tracking by 25%as compared with C-BO,by 45%when compared with the GA and by 56%when compared with ***,the integral absolute errors of six controllers are investigated to demonstrate the feasibility of *** root mean square of the errors of six controllers using CSBO is improved by 68.27%when compared with GA,by 22.57%when compared with C-BO and by 38.42%when compared with *** indicators demonstrate the feasibility of CSBO when compared with other algorithms with the same OWCPP.

关键词： circulatory system-based optimization approach adaptive fuzzy logic controller grid-tied oscillating water column power plant maximum power point tracking

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Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

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Clean energy 2024年第1期8卷 188-196页

作者： Basem.e.elnagi ahmed m.Ismaiel hany S.e.mansour m.n.Abd-Alwahab electrical engineering Department Faculty of EngineeringSuez Canal UniversityIsmailia 41522Egypt

A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost *** was directly coupled to a single-phase(two levels-four pulses)inverter without a *** pulse-width modu-lation signal was used to independently regulate every converter *** converter was modelled using a mATLAB®/Simulink®environment and an appropriate voltage control *** analysis features of the suggested circuit were created and,through established experiments,the simulation results were verified.A single-phase(two levels-four pulses)inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage *** matches the voltage of the network in terms of amplitude and frequency.A sinusoidal pulse-width modulation approach was performed using a single-phase(two levels-four pulses)pulse-width modulation *** results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63μs compared with 180μs in conventional techniques.

关键词： Pem fuel cell pulse-width modulation single-phase inverter and double-stage DC/DC boost converter

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Production of porous silica by the combustion of rice husk ash for tundish lining

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Journal of University of Science and Technology Beijing 2008年第3期15卷 307-313页

作者： Y.m.Z.ahmed e.m.ewais Z.I.Zaki Central metallurgical Research and Development Institute(CmRDI)

In order to study the production of porous silica compacts by the combustion of rice husk ash （RhA） for tundish lining, the experimental design technique was used to evaluate the effect of firing tem.erature, soaking time and compaction pressure on controlling both the porosity degree and compressive strength of rice husk ash compacts. The results revealed that while the porosity degree of the compacts decreased with the increase in the entire studied parameters, the compressive strength exhibited another trend especially at a lower soaking time. At a lower soaking time, the increase in firing tem.erature led to a slight decrease in compressive strength and then increasing thereafter. The porous silica compacts having 30% porosity and 〉 2.5 mPa compressive strength suitable for tundish lining could be obtained from the combustion of rice husk ash compacts.

关键词： porous silica rice husk ash tundish lining compressive strength porosity

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