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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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GROWTH mORPHOLOGIeS OF A BINARY ALLOY WITH LOW ANISOTROPY IN DIReCTIONAL SOLIDIFICATION

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Acta metallurgica Sinica(english Letters) 2007年第4期20卷 258-264页

作者： m.e Li G. C. Yang School of materials Science and engineering Xi＇an Jiaotong UniversityXi＇an 710049 China State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

Two new classes of growth morphologies, called doublons and seaweed, were simulated using a phase-field method. The evolution of doublon and seaweed morphologies was obtained in directional solidification. The influence of orientation and velocity on the growth morphology was investigated. It was indicated that doublons preferred growing with its crystallographic axis aligned with the heat flow direction. Seaweed, on the other hand, could be obtained by tilting the crystalline axis to 45°. Stable doublons could only exist in a range of velocity regime. Beyond this regime the patterns formed would be unstable. The simulation results agreed with the reported experimental results qualitatively.

关键词： growth morphologies low anisotropy phase-field method directional solidification

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Nanosecond pulse and dual-wavelength Q-switched 1.5 μm fiber laser using mAX phase Cr2TiAlC2 saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： ahmed Shakir AL-HITI Hiba HASSAN Department of electrical engineering Faculty of Engineering University of Anbar Department of Laser and Optoelectronics engineering University of Technology-Iraq

We demonstrated a new type of mAX phase material, chromium titanium aluminum carbide（Cr2TiAlC2） polymer film, to generate a passively Q-switched erbium-doped fiber laser（eDFL）. The film thickness was measured to be around 45 μm, which was fabricated using the em.edding method with polyvinyl alcohol（PVA） polymer as hoster. The saturable absorber（SA） film demonstrates a dual-wavelength passively Q-switched eDFL which operates at 1 531 nm and 1 560.19 nm, respectively. The Q-switching pulse duration could be varied from 2.46 μs to 770 ns, while the repetition rate varied from 92.76 kHz to 106.6 kHz with an increasing input pumping range from 154 mW to 300 mW. The maximum output power and pulse energy of 15.05 mW and 141.18 nJ were obtained at the maximum input power of 300 mW, respectively.

关键词： Saturable absorbers

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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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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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modeling natural convection boundary layer flow of micropolar nanofluid over vertical permeable cone with variable wall tem.erature

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Applied mathematics and mechanics(english edition) 2017年第8期38卷 1171-1180页

作者： S.e.ahmed Department of mathematics Faculty of ScienceSouth Valley UniversityQena 83523Egypt

This paper discusses the natural convection boundary layer flow of a micropo- lax nanofluid over a vertical permeable cone with variable wall tem.eratures. Non-similax solutions are obtained. The nonlineaxly coupled differential equations under the boundary layer approximations governing the flow axe solved numerically using an efficient, itera- tive, tri-diagonal, implicit finite difference method. Different experimental correlations for both nanofluid effective viscosity and nanofluid thermal conductivity are considered. It is found that as the vortex-viscosity parameter increases, both the velocity profiles and the local Nusselt num.er decrease. Also, among all the nanoparticles considered in this investigation, Cu gives a good convection.

关键词： micropolar nanofluid non-similar solution cone finite difference method,non-uniform heating

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GIS-based flash flooding susceptibility analysis and water management in arid mountain ranges:Safaga Region,Red Sea mountains,egypt

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Journal of mountain Science 2023年第12期20卷 3665-3686页

作者： ahmed e.eL-RAYeS mohamed O.ARNOUS ahmed m.HeLmY Geology Department Faculty of ScienceSuez Canal UniversityIsmailia 41522Egypt Geology Department Faculty of ScienceArish UniversityArish 45511 North SinaiEgypt

The Safaga Region(SR)is part of the Red Sea mountain range in *** flash flooding is now an inescapable event,wreaking havoc and causing massive loss of life and *** majority of the floodwater,however,has been wasted as runoff to the Red Sea,which,if used wisely,could m.et a fraction of the water demands for a variety of applications in this *** current work aims to use GIS techniques to integrate remote sensing data for evaluating,mitigating,and managing flash floods in *** data set comprised Tropical Rainfall measuring mission(TRmm)thematic rainfall data,1:50,000 scale topographical map sheets,geological maps,the ASTeR Digital elevation model(ASTeR GDem),Landsat 7 enhanced Thematic mapper"(eTm7+),and Landsat 8 Operational Land *** flash flood risk model of SR is developed using ArcGIS-10.3 geoprocessing tools integrating all the causal factors thematic *** final flood risk model for the SR suggests that 57%of the total basins in the SR are at high risk of *** 38%of all basins are at moderate flood *** remaining 5%of basins are less prone to ***-prone zones were identified,suitable dam-building sites were located,and extremely probable areas for water recharge were *** the basis of reliable scientific data,structural and non-structural mitigation strategies that might reduce the damage susceptibility,alleviate the sensitivity of the flash flood,and best utilize its water supply were recom.ended.

关键词： Flash floods GIS Susceptibility Water management Arid mountains egypt

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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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A New Jacobi elliptic Function expansion method for Solving a Nonlinear PDe Describing Pulse Narrowing Nonlinear Transmission Lines

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Journal of Partial Differential equations 2015年第2期28卷 128-138页

作者： ZAYeDe. m.e ALURRFI K. A. e. Department of mathema tics Faculty of Science Zagazig University P. O. Box 44519Zagazig Egypt.

In this article, we apply the first elliptic function equation to find a new kind of solutions of nonlinear partial differential equations （PDes） based on the ho- mogeneous balance method, the Jacobi elliptic expansion method and the auxiliary equation method. New exact solutions to the Jacobi elliptic functions of a nonlinear PDe describing pulse narrowing nonlinear transmission lines are given with the aid of computer program, e.g. maple or mathematica. Based on Kirchhoff＇s current law and Kirchhoff＇s voltage law, the given nonlinear PDe has been derived and can be reduced to a nonlinear ordinary differential equation （ODe） using a simple transformation. The given method in this article is straightforward and concise, and can be applied to other nonlinear PDes in mathematical physics. Further results may be obtained.

关键词： New Jacobi elliptic function expansion method pulse narrowing nonlinear transmis-sion lines exact solutions Kirchhoff's current law Kirchhoff's voltage law.

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