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Effect of Lanthanum.on Nodule Count and Nodularity of Ductile Iron

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Journal of Rare Earths 2007年第5期25卷 533-536页

作者： m. ashraf Sheikh Javed Iqbal University of Engineering & Technology

The present study aim. at finding out the effect of the addition of a single rare earth elem.nt, that is, lanthanum.on the nodularity and nodule count of ductile iron under controlled conditions. For this purpose, four m.lts with different com.ositions were m.de, using a 28 kg inductotherm.m.dium.frequency induction furnace. The tem.erature was carefully m.intained between 1400 and 1450 ℃ for these heats. A good quality charge consisting of Sorel m.tal, ferrosilicon, Swedish iron, ferrosilicon m.gnesium. and ferrosilicon lanthanum.was used for the production of m.lts. A vertically parted sand m.uld was used for casting of 10 test bars m.de from.local silica sand. Standard coin sam.les were chill-cast to conduct chem.cal analysis of the ductile iron. m.erostructure study of the sam.les was conducted using a Leica optical m.croscope. Nodule count and nodularity of the sam.les were carried out using an im.ge analyzer. The results obtained indicated that with the increased addition of lanthanum.the nodule count of ductile iron increased, thus m.king it evident that it played a significant role in increasing the m.chanical properties. The highest nodule count of 467 was obtained with the addition of 0.03% lanthanum. However, the effect of lanthanum.on nodularity was negligible with nodularity ranging from.81% to 83 %.

关键词： ductile iron m.schm.tal nodulization nodulafity nodule count rare earths

m.D flow and heat transfer of m.cropolar fluid between two porous disks

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Applied m.them.tics and m.chanics(English Edition) 2012年第1期33卷 51-64页

作者： m. ashraf A. R. WEHGAL Centre for Advanced Studies in Pure and Applied m.them.tics Bahauddin Zakariya University Departm.nt of m.them.tics Stockholm University

A num.rical study is carried out for the axisym.etric steady lam.nar incom.ressible flow of an electrically conducting m.cropolar fluid between two infinite parallel porous disks with the constant uniform.injection through the surface of the disks. The fluid is subjected to an external transverse m.gnetic field. The governing nonlinear equations of m.tion are transform.d into a dim.nsionless form.through yon Karm.n＇s sim.larity transform.tion. An algorithm.based on a finite difference schem. is used to solve the reduced coupled ordinary differential equations under associated boundary conditions. The effects of the Reynolds num.er, the m.gnetic param.ter, the m.cropolar param.ter, and the Prandtl num.er on the flow velocity and tem.erature distributions are discussed. The results agree well with those of the previously published work for special cases. The investigation predicts that the heat transfer rate at the surfaces of the disks increases with the increases in the Reynolds num.er, the m.gnetic param.ter, and the Prandtl num.er. The shear stresses decrease with the increase in the injection while increase with the increase in the applied m.gnetic field. The shear stress factor is lower for m.cropolar fluids than for Newtonian fluids, which m.y be beneficial in the flow and therm.l control in the polym.ric processing.

关键词： m.D flow porous disk m.cropolar fluid heat transfer m.crorotation

m.D non-Newtonian m.cropolar fluid flow and heat transfer in channel with stretching walls

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Applied m.them.tics and m.chanics(English Edition) 2013年第10期34卷 1263-1276页

作者： m. ashraf N. JAm.EL K. ALI Centre for Advanced Studies in Pure and Applied m.them.tics Bahauddin Zakariya UniversityMultan 60800 Pakistan Centre for Advanced Studies in Pure and Applied m.them.tics Bahauddin Zakariya UniversityMultan 60800 Pakista

A study is presented for m.gnetohydrodynam.cs （m.D） flow and heat transfer characteristics of a viscous incom.ressible electrically conducting m.cropolar fluid in a channel with stretching walls. The m.cropolar m.del introduced by Eringen is used to describe the working fluid. The transform.d self sim.lar ordinary differential equations together with the associated boundary conditions are solved num.rically by an algorithm.based on quasi-linearization and m.ltilevel discretization. The effects of som. physical param.ters on the flow and heat transfer are discussed and presented through tables and graphs. The present investigations m.y be beneficial in the flow and therm.l control of polym.ric processing.

关键词： m.gnetohydrodynam.cs (m.D) heat transfer stretching wall couple stress quasi-linearization

Growth Responses of Wheat Cultivars to Rock Phosphate in Hydroponics

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Pedosphere 2009年第3期19卷 398-402页

作者： m. ashraf RAHm.TULLAH m. A. m.QSOOD S. KANWAL m. A. TAHIR L. ALI Directorate of Land Reclam.tion Irrigation & Power Department Punjab (Pakistan) Institute of Soil & Environm.ntal Sciences University of Agriculture Faisalabad (Pakistan)

Screening cultivars to grow under conditions of low phosphorus (P) availability and utilize P efficiently from.com.ounds of low solubility in soils m.y be beneficial to overcom. poor plant growth in P-deficient soils. The growth behavior and P utilization efficiency of seven wheat cultivars grown in hydroponics were studied, using rock phosphate as P source. The wheat cultivars grown for 30 days were significantly different in biom.ss accum.lation, P uptake and P utilization efficiency. The dry m.tter production of all the cultivars was significantly correlated with P uptake, which in turn correlated to the drop in the root m.dium.pH. The ranking of wheat cultivars on the basis of dry m.tter yield, P uptake and P utilization efficiency was Zam.ndar 80 > Yecora > C 271 > WL 711 > Barani 83 > PARI 73 > Rohtas. The cultivar Zam.ndar 80 appeared to possess the best growth potential in P-deficient soils.

关键词： cultivars hydroponics nutrition rockphosphate wheat

Wave propagation of a functionally graded plate via integral variables with a hyperbolic arcsine function

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 547-561页

作者： m.khtar Ellali m.khtar Bouazza ashraf m.Zenkour Sm.rt structures Laboratory University of Ain TemouchentAin Temouchent 46000Algeria Departm.nt of Civil Engineering University Tahri Mohamed of BecharBechar 08000Algeria Departm.nt of m.them.tics Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Laboratory of m.terials and Hydrology(Lm.) University of Sidi Bel AbbesSidi Bel Abbes 22000Algeria Departm.nt of m.them.tics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh 33516Egypt

Several studies on functionally graded m.terials(FGm.)have been done by researchers,but few studies have dealt with the im.act of the m.dification of the properties of m.terials with regard to the functional propagation of the waves in *** work aim. to explore the effects of changing com.ositional characteristics and the volum. fraction of the constituent of plate m.terials regarding the wave propagation response of thick plates of *** m.del is based on a higher-order theory and a new displacem.nt field with four unknowns that introduce indeterm.nate integral variables with a hyperbolic arcsine *** FGm.plate is assum.d to consist of a m.xture of m.tal and ceram.c,and its properties change depending on the power functions of the thickness of the plate,such as linear,quadratic,cubic,and inverse *** utilizing Ham.lton’s principle,general form.lae of the wave propagation were obtained to establish wave m.des and phase velocity curves of the wave propagation in a functionally graded plate,including the effects of changing com.ositional characteristics of m.terials.

关键词： FGm.plate effects of m.terial properties wave propagation indeterm.nate integral variables inverse sinus hyperbolic function

Sim.lation of Diode-Pum.ed Q-Switched Nd:YAG Laser Generating Eye-Safe Signal in IOPO Environm.nt

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Optics and Photonics Journal 2012年第3期2卷 167-172页

作者： m.an m. ashraf m.ham.ad Siddique Institute of Industrial Control System P .O. Box 1398 Rawalpindi Pakistan

Num.rical sim.lation of diode-pum.ed Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Param.tric Oscillator (IOPO) is presented. Starting from.rate equations, the tim. dependent laser equations have been solved num.rically, whereas the space-dependent OPO equations analytically. Our results show that 1.4 J diode laser (810 nm. pulse with 200 m.ec width, delivers 30 m. Nd:YAG laser (1064 nm. pulse with 5 n-second width. This Nd:YAG laser further generates 9 m. eye safe signal (1570 nm. pulse with 2.5 n-second width.

关键词： Sim.lation Diode Laser Q-Switched Nd:YAG Laser Eye-Safe Laser Signal Idler IOPO Rate Equations Out-Put Power KTP Non-Linear Crystal Pum. Beam Waist

Cytokinin Perception Also Starts at the Plasm. m.m.rane

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m.lecular Plant 2020年第11期13卷 1534-1534页

作者： m.Arif ashraf Departm.nt of Biology University of Massachusetts AmherstAmherstMAUSA

The plant horm.ne cytokinin regulates diverse biological processes,including em.ryogenesis,cell division and differentiation,root and shoot architecture,vascular developm.nt,and form.tion of shoot and root lateral *** endoplasm.c reticulum.ER)is considered as the prim.ry cytokinin perception site based on the known subcellular localization of the cytokinin receptors.

关键词： organs shoot Plasm.

Physical Properties of Lithium.Containing Cadm.um.Phosphate Glasses

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Journal of m.dern Physics 2010年第4期1卷 201-205页

作者： m.ham.ad Altaf m. ashraf Chaudhry 不详

Lithium.cadm.um.phosphate glasses were prepared by m.lt quench technique. These glasses contain a m.le % com.osition of x% Li2O-(50-x)% CdO-50%P2O5. The quantity x varies from.0-40 m.le%. The physical properties reported in this paper are m.ss density ρ, m.dulus of rigidity η, coefficient of linear expansion α, transition tem.erature Tg, Softening tem.erature Ts, Oxygen packing density, m.lar volum. and lithium.ion concentration. The m.ss density, oxygen packing density, m.dulus rigidity, transition tem.erature and softening tem.erature show decreasing trend with increasing concentration of lithium.ions in these glasses, where m.lar volum. and coefficient of linear expansion increases with increasing concentration of Li2O.

关键词： Phosphate Glasse m.ss Density m.dulus of Rigidity Coefficient of Linear Expansion Transition Tem.erature m.lar Volum.

Im.acts of Tem.erature and Frequency on the Dielectric Properties for Insight into the Nature of the Charge Transports in the Tl2S Layered Single Crystals

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Journal of m.dern Physics 2011年第1期2卷 12-25页

作者： Aly m. Badr Haroun A. Elshaikh Ibraheim.m. ashraf 不详

Investigation of the electric properties of sem.-conducting m.terials in an applied ac electric fields gives inform.tion about the nature of charge transport and localized states in the forbidden gap. Layered crystals usually contain structural defects, such as dislocations and vacancies that m.y form.a high density of localized states near the Ferm. level. So, the current study was carried out for insight into the dielectric Properties of Tl2S layered single crystals. These properties were studied using the ac m.asurem.nts in the low tem.eratures ranging from.77 to 300 K. The real part of dielectric constant ε?, im.ginary part of dielectric constant ε?, the dissipation factor tan δ and the alternating current conductivity σac were m.asured in an applied ac electric field of frequencies extending from.2.5 to 50 kHz. Based on the dependencies of these dielectric param.ters on both the frequency and tem.erature, the dielectric properties of the crystals under investigation were elucidated and analyzed. The ac conductivity was found to obey the power law σac(ω) = Aωs with which the values of the exponent s were evaluated to be less than unity in the range 0.21 ≥ s ≥ 0.19. Furtherm.re, it was found that the tem.erature dependence of ac conductivity follows the Arrhenius relation via which the im.act of tem.erature on the electrical processes in an applied ac electric field was illustrated and analyzed. The influences of tem.erature and frequency on both the exponent s and band gap were also discussed in this investigation.

关键词： Structural Defects in Layered Crystals Dielectric Param.ters Nature of Charge Transports Chalcogenide Sem.conductors