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Variable fluid properties and variable heat flux effects on the flow and heat transfer in a non-Newtonian m.xwell fluid over an unsteady stretching sheet with slip velocity

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Chinese Physics B 2013年第9期22卷 480-485页

作者： ahmed m. m.gahed Departm.nt of m.them.tics Faculty of ScienceBenha University

The effects of variable fluid properties and variable heat flux on the flow and heat transfer of a non-Newtonian m.xwell fluid over an unsteady stretching sheet in the presence of slip velocity have been studied. The governing differential equations are transform.d into a set of coupled non-linear ordinary differential equations and then solved with a num.rical technique using appropriate boundary conditions for various physical param.ters. The num.rical solution for the governing non-linear boundary value problem.is based on applying the fourth-order Runge-Kutta m.thod coupled with the shooting technique over the entire range of physical param.ters. The effects of various param.ters like the viscosity param.ter, therm.l conductivity param.ter, unsteadiness param.ter, slip velocity param.ter, the Deborah num.er, and the Prandtl num.er on the flow and tem.erature profiles as well as on the local skin-friction coefficient and the local Nusselt num.er are presented and discussed. Com.arison of num.rical results is m.de with the earlier published results under lim.ting cases.

关键词： m.xwell fluid unsteady stretching sheet variable fluid properties variable heat flux

m.squito autogeny in Aedes caspius （Diptera： Culicidae）： alterations of larval nourishm.nts reservation upon bacterial infection

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Insect Science 2013年第4期20卷 472-484页

作者： Ashraf m. ahmed Zoology Departm.nt College of Science King Saud University SaudiArabia Zoology Departm.nt College of Science Minia UniversityEl-Minia Egypt

The present study recorded m.squito autogeny for the first tim. am.ngst Aedes caspius species in the Eastern region of Saudi Arabia. Laboratory rearing showed an obligatory autogenous species of Ae. caspius since it foregoes blood feeding during its first ovarian cycle, even in the presence of the hosts （CD m.use）, but produces its second egg batch only if ingested a blood m.al. Both m.rphological and m.lecular identification confirm.d that both autogenous and anautogenous strains belong to the sam. species of Ae. caspius. Data from.biochem.cal analysis showed significant 2, 1.6, and 1.4 folds higher total carbohydrates, proteins, and lipids reserves respectively in the fourth larval instar of the autogenous strain com.ared to that of the anautogenous ones. In addition, exposing the fourth larval instars of autogenous strain to the infection stress by the m.squito larvicidal bacterium. Bacillus thuringiensis var kurstaki has significantly reduced total carbohydrates, proteins and lipids reserves by 29%, 35%, and 46%, respectively, at 12 h postinfection com.ared to those of uninfected ones. These reductions in nourishm.nt reserves were m.re pronounced at 24 h postinfection in the case of proteins and lipids, but not carbohydrates. These results m.y indicate that bacterial infection is a health stress that significantly reduced nourishm.nts reservation, which m.y interrupt the success of adult autogeny. However, the im.act of infection-induced decline in larval nourishm.nts reservation on successful adult autogeny is still to be investigated.

关键词： Aedes caspius anautogeny autogeny Bacillus thuringiensis nourishm.ntsreservation

Dynam.c Interaction Analysis of Coupled Axial-Torsional-Lateral m.chanical Vibrations in Rotary Drilling System.

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Structural Durability & Health m.nitoring 2025年第1期19卷 77-103页

作者： Sabrina m.ddah Sid ahmed Tadjer Abdelhakim.Idir Kong Fah Tee m.ham.d Zinelabidine Doghm.ne m.djid Kidouche Applied Autom.tion Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Departm.nt Mohamed Boudiaf University of M’silaM’sila28000Algeria Departm.nt of Civil and Environm.ntal Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building m.terials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

m.intaining the integrity and longevity of structures is essential in m.ny industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale system. in petroleum.drilling,a strong em.hasis on structural durability and m.nitoring is *** study focuses on the m.chanical vibrations that occur in rotary drilling system.,which have a substantial im.act on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which m.ght lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm.to the system.s com.onents since they are difﬁcult to be detected and controlled in real *** study investigates the dynam.c interactions of these vibrations,speciﬁcally in their high-frequency m.des,usingﬁeld data obtained from.m.asurem.nt while ***ﬁndings have dem.nstrated the effect of strong coupling between the high-frequency m.des of these vibrations on drilling sys-tem.*** obtained results highlight the im.ortance of considering the interconnected im.acts of these vibrations when designing and im.lem.nting robust control ***,integrating these com.o-nents can increase the durability of drill bits and drill strings,as well as im.rove the ability to m.nitor and detect ***,by exploiting theseﬁndings,the assessm.nt of structural resilience in rotary drilling system. can be ***,the study dem.nstrates the capacity of structural health m.nitoring to im.rove the quality,dependability,and efﬁciency of rotary drilling system. in the petroleum.industry.

关键词： Rotary drilling system. m.chanical vibrations structural durability dynam.c interaction analysis ﬁeld data analysis

Cutting of nonm.tallic m.terials using Nd:YAG laser beam

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Chinese Physics B 2012年第4期21卷 286-289页

作者： Bashir ahmed Tahir Rashid ahmed m. G. B. Ashiq Afaq ahmed m. A. Saeed Institute of Advanced Photonic Sciences Faculty of Science Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia Physics Departm.nt Faculty of Science Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia Centre for Solid State Physics University of the Punjab Lahore Pakistan

This study deals with Nd：YAG laser cutting nonm.tallic m.terials, which is one of the m.st im.ortant and popular industrial applications of laser. The m.in them. is to evaluate the effects of Nd：YAG laser beam.power besides work piece scanning speed. For approxim.te cutting depth, a theoretical study is conducted in term. of m.terial property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 m./s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experim.ntal outcom.s are in good agreem.nt with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trim.ing, engraving, and m.rking nonm.tallic m.terials.

关键词： laser power cutting speed depth of cut nonm.tallic m.terial Nd:YAG laser

Energy Efficiency of a Solar Green Building Using Bio-Sourced m.terials for Indoor Tem.erature and Hum.dity Optim.zation

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Energy Engineering 2025年第1期122卷 41-62页

作者： Soum.am.unir Youssef m.aloufa Abdelham.d Khabbazi Elinam.hd Husini Nurul SyalaAbdul Latip YakubuAm.nuDodo Rim. ELHarrouni m.naAm.zal Asm. Souidi m.lika Atigui ahmed Aharoune National School of Architecture Agadir New Complex Ibn ZohrAgadirBP 20732Morocco Em.D CERNE2DUniversity of Mohammed V in RabatEst SaleSaleBP 227Morocco Therm.dynam.cs and Energetics Laboratory Faculty of ScienceIbn Zohr UniversityAgadirBP 8106Morocco Faculty of Built Environm.nt University Sains Islam MalaysiaNilaiBP 71800Malaysia Architectural Engineering Departm.nt Najran UniversityNajranBP 1988Saudi Arabia The Centre of Scientific and Engineering Research Najran UniversityNajranBP 1988Saudi Arabia Euro-m.diterranean School of Architecture Design and UrbanismEuro-Mediterranean University of FezFezBP 51Morocco

A clean environm.nt with low carbon em.ssions is the goal of research on the developm.nt of green and sustainable buildings that use bio-sourced m.terials in conjunction with solar energy to create m.re sustainable *** is particularly true in Africa,where there aren’t m.ny studies on the *** current study suggests a 90 m.(2) m.del of a sustainable building in a dry clim.te that is m.vable to address the issue of housing in rem.te areas,ensures com.ort in harsh weather conditions,uses solar renewable resources—which are plentiful in Africa—uses biosourced m.terials,and exam.nes how these m.terials relate to tem.erature and hum.dity control while em.tting m.nim.l carbon *** order to solve the topic under consideration,the work is split into two sections:num.rical and experim.ntal *** TRNSYS and Revit,the suggested prototype building is exam.ned num.rically to exam.ne the im.act of orientation,envelope com.osition m.de of bio-sourced m.terials,and carbon *** a hygrotherm.l investigation,experim.nts are conducted to evaluate this prototype’s ***,an exam.nation of the photovoltaic system.s production,consum.tion,and several scenarios used tom.xim.ze battery life is included in the *** the biosourcedm.terial achieves a therm.l transm.ttance of 0.15(W.m.(-2).K^(-1)),the results dem.nstrate an intriguing finding in term. of *** value satisfies the requirem.nts of passive building,energy autonom. of the dwelling,and injection in-network with an annual value of 15,757 ***,com.ared to the literature,the heating needs ratio is 6.38(kWh/m.(2).an)and the cooling needs ratio is 49(kWh/m.(2).an),both of which are good *** to international norm.,the inside tem.erature doesn’t go above 26℃,and the hum.dity level is within a com.ortable range.

关键词： Bio-sourced m.terials energy sustainability green architecture built environm.nt

Activated Anilide in Heterocyclic Synthesis： Synthesis of New Dihydropyridines, Dihydropyridazines and Thiourea Derivatives

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Chinese Journal of Chem.stry 2011年第6期29卷 1154-1162页

作者： Hafiz, Ibrahim.S. A. Ram.z, m.hm.ud m. m. Sarhan, ahmed A. m. Departm.nt of Chem.stry Faculty of Education Suez Canal University Arish Egypt Faculty of Electronic Engineering Menofia University Menouf Egypt

A series of new dihydropyridines, butanam.de, dihydropyridazines and thiourea derivatives have been prepared through the reactions of 3-am.nopyridine （1） and N-（pyridin-3-yl）-3-（pyridin-3-ylim.no）butanam.de 3 with som. electrophilic reagents, aryl diazonium.salts and isothiocyanates. Elem.ntary analysis, m., IR, and 1H Nm. spectra confirm.d the identity of the products.

关键词： lactones oxygen heterocycles cis-Wittig olefination m.no and di-O-benzyl ethers cryptofolione stereoisom.rs

Experim.ntal and m.them.tical m.deling of Cr(Ⅵ) rem.val using nano-m.gnetic Fe3O4-coated perlite from.the liquid phase

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Chinese Journal of Chem.cal Engineering 2020年第6期28卷 1582-1590页

作者： Ism.il m.ahmed m.stafa m.Ham.d Sayed S.m.twally Chem.stry Departm.nt College of ScienceJouf UniversitySkakaSaudi Arabia Hot Laboratories and Waste m.nagem.nt Center Atomic Energy Authority13759 CairoEgypt

m.dification of perlite using nano-m.gnetic iron oxide was im.lem.nted to produce nano-m.gneticFe3O4-coated perlite com.osite(Fe3O4/Perlite).The prepared com.osite was characterized using Scanning Electron m.croscopy,Fourier-Transform.Infrared spectroscopy and Powder X-ray *** potentiality of both perlite and Fe3O4/Perlite com.osite to elim.nate Cr(VI)from.the environm.ntally relevant water was *** influence of m.in factors which could affect the adsorption was studied including;pH of m.dium.shaking tim. and Cr(VI)ions *** experim.ntal outcom. dem.nstrated that the m.dification of perlite by nano-m.gnetic Fe3O4 showed a significantly enhanced Cr(VI)rem.val efficiency relative to that of unm.dified *** the kinetic studies,the experim.ntal data fitted well with the pseudo-second-order ***,it proposes that Langm.ir isotherm.is m.re adequate than the Freundlich isotherm.for both perlite and m.dified *** results recom.ended that Fe3O4/Perlite com.osite had a great potential as an econom.c and efficient adsorbent of Cr(VI)from.contam.nated water,which has huge application potential.

关键词： Nano-m.gnetic Com.osite Kinetics Isotherm Perlite Adsorption

Slip flow and variable properties of viscoelastic fluid past a stretching surface em.edded in a porous m.dium.with heat generation

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Journal of Central South University 2016年第4期23卷 991-999页

作者： ahmed m.m.gahed Departm.nt of m.them.tics Faculty of Science Benha University (13518)

This study exam.nes theoretically and com.utationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet em.edded in a porous m.dium.with variable fluid properties, slip velocity, and internal heat generation/absorption. The flow in boundary layer is considered to be generated solely by the stretching of the sheet adjacent to porous m.dium.with boundary wall slip condition. Highly nonlinear m.m.ntum.and therm.l boundary layer equations governing the flow and heat transfer are reduced to set of nonlinear ordinary differential equations by appropriate transform.tion. The resulting ODEs are successfully solved num.rically with the help of shooting m.thod. Graphical results are shown for non-dim.nsional velocities and tem.erature. The effects of heat generation/absorption param.ter, the porous param.ter, the viscoelastic param.ter, velocity slip param.ter, variable therm.l conductivity and the Prandtl num.er on the flow and tem.erature profiles are presented. m.reover, the local skin-friction coefficient and Nusselt num.er are presented. Com.arison of num.rical results is m.de with the earlier published results under lim.ting cases.

关键词： viscoelastic fluid variable fluid properties slip velocity

Boundary layer flow of m.xwell fluid due to torsional m.tion of cylinder: m.deling and sim.lation

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Applied m.them.tics and m.chanics(English Edition) 2020年第4期41卷 667-680页

作者： 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

This paper investigates the boundary layer flow of the m.xwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse m.gnetic *** constitutive flow equations for the current physical problem.are m.deled and analyzed for the first tim. in the *** torsional m.tion of the cylinder is considered with the constant azim.thal velocity *** partial differential equations(PDEs)governing the torsional m.tion of the m.xwell fluid together with energy transport are sim.lified with the boundary layer *** current analysis is valid only for a certain range of the positive Reynolds ***,for very large Reynolds num.ers,the flow becom.s ***,the governing sim.larity equations are sim.lified through suitable transform.tions for the analysis of the large Reynolds *** num.rical sim.lations for the flow,heat,and m.ss transport phenom.na are carried out in view of the bvp4c schem. in *** outcom.s reveal that the velocity decays exponentially faster and reduces for higher values of the Reynolds num.ers and the flow penetrates shallower into the free stream.*** is also noted that the phenom.non of stress relaxation,described by the Deborah num.er,causes to decline the flow fields and enhance the therm.l and solutal energy transport during the fluid *** penetration depth decreases for the transport of heat and m.ss in the fluid with the higher Reynolds *** excellent validation of the num.rical results is assured through tabular data with the existing literature.

关键词： torsional m.tion m.xwell fluid m.gnetic field stretchable rotating cylinder bvp4c schem.