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a.plied Ma.hema.ics.a.d Mecha.ics.Englis. Edition) 2012年第1期33卷 81-98页

作者： s. a. eftekhari a. a. Ja.a.I Depa.tment of Mecha.ica. Engineering K. N. Toosi University of Technology

This.pa.er pres.nts.a.combined a.plica.ion of the finite element method （FEM） a.d the differentia. qua.ra.ure method （DQM） to vibra.ion a.d buckling problems.of recta.gula. pla.es. The propos.d s.heme combines.the geometry flexibility of the FEM a.d the high a.cura.y a.d efficiency of the DQM. The a.cura.y of the pres.nt method is.demons.ra.ed by compa.ing the obta.ned res.lts.with thos. a.a.la.le in the litera.ure. It is.s.own tha. highly a.cura.e res.lts.ca. be obta.ned by us.ng a.s.a.l number of finite elements.a.d DQM s.mple points. The propos.d method is.s.ita.le for the problems.cons.dered due to its.s.mplicity a.d potentia. for further development.

关键词： finite element method (FEM) differentia. qua.ra.ure method (DQM) recta.gula. pla.e free a.d forced vibra.ion buckling a.a.ys.s

Nonlinea. forced vibra.ion in a.s.bcritica. regime of a.porous.functiona.ly gra.ed pipe conveying fluid with a.reta.ning clip

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a.plied Ma.hema.ics.a.d Mecha.ics.Englis. Edition) 2025年第1期46卷 101-122页

作者： M.GHOLa.I M.eftekhari Depa.tment of Mecha.ica. Engineering Shahid Bahonar University of Kerman

This.s.udy exa.ines.the nonlinea. beha.iors.of a.cla.ped-cla.ped porous.pipe ma.e of a.functiona.ly gra.ed ma.eria.(FGM) tha. conveys.fluids.a.d is.equipped with a.reta.ning clip, focus.ng on prima.y res.na.ce a.d s.bcritica. dyna.ics. The nonlinea. governing equa.ions.for the FGM pipe a.e derived by the extended Ha.ilton's.principle, a.d s.bs.quently dis.retized through the a.plica.ion of the Ga.erkin *** direct method of multi-s.a.es.is.then us.d to s.lve the derived equa.ions. a.thorough a.a.ys.s.of va.ious.pa.a.eters. including the clip s.iffnes., the power-la. index, the poros.ty, a.d the clip loca.ion, is.conducted to ga.n a.comprehens.ve unders.a.ding of the s.s.em's.nonlinea. dyna.ics. Through the a.a.ys.s.of the firs. na.ura. frequency, the s.udy highlights.the influence of the flow velocity a.d the clip s.iffnes., while the compa.is.ns.with meta.lic pipes.empha.0}ze the role of FGM compos.tion. The exa.ina.ion of the forced res.ons. curves.revea.s.s.ddle-node bifurca.ions.a.d their dependence on pa.a.eters.s.ch a.0}the detuning pa.a.eter a.d the power-la. index, offering va.ua.le ins.ghts.into the s.s.em's.nonlinea. res.na.t beha.ior. Furthermore, the frequency-res.ons. curves.illus.ra.e the ha.dening nonlinea.ities.influenced by fa.tors.s.ch a.0}the poros.ty a.d the clip s.iffnes., revea.ing nua.ced effects.on the s.s.em res.ons. a.d res.na.ce cha.a.teris.ics. This.comprehens.ve a.a.ys.s.enha.ces.the unders.a.ding of nonlinea. beha.iors.in FGM porous.pipes.with a.reta.ning clip, providing key ins.ghts.for pra.tica. engineering a.plica.ions.in s.s.em des.gn a.d optimiza.ion.

关键词：

a.a.ytica. determina.ion of non-loca. pa.a.eter va.ue to inves.iga.e the a.ia. buckling of na.os.ells.a.fected by the pa.0}ing na.ofluids.a.d their velocities.cons.dering va.ious.modified cylindrica. s.ell theories

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Chines. Phys.cs.B 2023年第4期32卷 511-528页

作者： s.heil Oveis.i a.za. Gha.0}emi Mehdi s.lehi s.a.i eftekhari s.eed Zia.i-Ra. Depa.tment of Mecha.ica. Engineering Najafabad BranchIslamic Azad UniversityNajafabadIran Depa.tment of Mecha.ica. Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahrIran Depa.tment of Mecha.ica. Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran

We a.a.ytica.ly determine the nonloca. pa.a.eter va.ue to a.hieve a.more a.cura.e a.ia.-buckling res.ons. of ca.bon na.os.ells.conveying na.ofluids. To this.end, the four pla.es.s.ells. cla.0}ica. theories.of Love, Fl ¨ugge, Donnell, a.d s.nders.a.e genera.ized us.ng Eringen's.nonloca. ela.0}icity theory. By combining thes. theories.in cylindrica. coordina.es.a.modified motion equa.ion is.pres.nted to inves.iga.e the buckling beha.ior of the na.ofluid-na.os.ructure-intera.tion problem. Herein, in a.dition to the s.a.l-s.a.e effect of the s.ructure a.d the pa.0}ing fluid on the critica. buckling s.ra.n,we dis.us. the effects.of na.oflow velocity, fluid dens.ty(na.o-liquid/na.o-ga.0}, ha.f-wa.e numbers. a.0}ect ra.io, a.d na.os.ell flexura. rigidity. The a.a.ytica. a.proa.h is.us.d to dis.retize a.d s.lve the obta.ned rela.ions.to s.udy the mentioned ca.0}s.

关键词： buckling nonloca. cylindrica. s.ell model a.ofluid-na.os.ructure intera.tion ca.bon na.otubes

Ma.netic field effects.on the nonlinea. vibra.ion of a.rotor

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a.plied Ma.hema.ics.a.d Mecha.ics.Englis. Edition) 2020年第2期41卷 289-312页

作者： M.eftekhari a.Da.1}TI-Ra.Ma.a.a.I a.Ma.IDI Depa.tment of Mecha.ica. Engineering Yazd UniversityYazd 89195-741Iran

The nonlinea. vibra.ion of a.rotor opera.ed in a.ma.netic field with geometric a.d inertia.nonlinea.ity is.inves.iga.ed. a. a.0}mmetric ma.netic flux dens.ty is.genera.ed,res.lting in the production of a.loa. on the rotor s.nce the a.r-ga. dis.ribution between the rotor a.d the s.a.or is.not uniform. This.electroma.netic loa. is.a.nonlinea. function of the dis.a.ce between the geometric centers.of the rotor a.d the s.a.or. The nonlinea. equa.ion of motion is.obta.ned by the inclus.on of the nonlinea.ity in the inertia. the curva.ure, a.d the electroma.netic loa.. a.ter dis.retiza.ion of the governing pa.tia. differentia. equa.ions.by the Ga.erkin method, the multiple-s.a.e perturba.ion method is.us.d to derive the a.proxima.e s.lutions.to the equa.ions. In the numerica. res.lts. the effects.of the electroma.netic pa.a.eter loa., the da.ping coefficient, the a.plitude of the initia. dis.la.ement, the ma.0} moment of inertia. a.d the rota.ion s.eed on the linea. a.d nonlinea. ba.kwa.d a.d forwa.d frequencies.a.e inves.iga.ed. The res.lts.s.ow tha. the ma.netic field ha.0}s.gnifica.t effects.on the nonlinea. frequency of os.illa.ion.

关键词： nonlinea. vibra.ion in-extens.ona. rotor nonlinea. curva.ure gyros.opic effect ma.netic field

Texture evolution a.d mecha.ica. a.is.tropy of a. ultra.ine/na.o-gra.ned pure copper tube proces.ed via.hydros.a.ic tube cyclic expa.s.on extrus.on

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Interna.iona. Journa. of Minera.s.Meta.lurgy a.d Ma.eria.s 2022年第12期29卷 2241-2251页

作者： s.yed Moien Fa.egh Gha.er Fa.a.i Ma.moud Mos.vi Ma.0}ha.i Moha.ma. eftekhari s.hool of Mecha.ica. Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran

Texture evolution a.d mecha.ica. a.is.tropic beha.ior of a. ultra.ine-gra.ned(UFG)pure copper tube proces.ed by recently introduced method of hydros.a.ic tube cyclic expa.s.on extrus.on(HTCEE)wa.0}*** the UFG tube,different deforma.ion beha.ior a.d a.s.gnifica.t a.is.tropy in tens.le properties.were recorded a.ong the longitudina. a.d periphera. *** HTCEE proces. increa.0}d the yield s.rength a.d the ultima.e s.rength in the a.ia. direction by 3.6 a.d 1.67 times.***,this.proces. increa.0}d the yield s.rength a.d the ultima.e s.rength in the periphera. direction by 1.15 a.d 1.12 times.*** ra.io of ultima.e tens.le s.rength in the periphera. direction to tha. in the a.ia. direction,a.0}a.criterion for mecha.ica. a.is.tropy,a.e 1.7 a.d 1.16 for the a.0}a.nea.ed coa.s.-gra.ned a.d the HTCEE proces.ed UFG tube,*** res.lts.a.e indica.ive of a.reducing effect of the HTCEE proces. on the mecha.ica. ***,a.ter HTCEE proces.,a.low los. of ductility wa.0}obs.rved in both directions.which is.a.other a.va.ta.e of HTCEE *** mea.0}rements.revea.ed a.s.ight increment of ha.dnes. va.ues.in the periphera. direction,which is.in a.reement with the trend of tens.le *** a.a.ys.s.wa.0}conducted in order to determine the orienta. dis.ribution of the *** obta.neda.pole figures.demons.ra.e the texture evolution a.d rea.firm the a.is.tropy obs.rved in mecha.ica. *** electron micros.opy microgra.hs.s.owed tha. different modes.of fra.ture occurred a.ter tens.le tes.ing in the two orthogona. directions.

关键词： s.vere pla.0}ic deforma.ion ultra.ine gra.ned hydros.a.ic tube cyclic expa.s.on extrus.on a.is.tropy texture

Mecha.is. of fra.ture in ma.ro- a.d micro-s.a.es.in hollow centre cra.ked dis. s.ecimen

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Journa. of Centra. s.uth Univers.ty 2015年第11期22卷 4426-4433页

作者： M.eftekhari a.Ba.hba.a. H.Ha.1}emolhos.eini H.a.rolla.i Depa.tment of Mining Engineering Isfahan University of Technology (IUT)

The hollow centre cra.ked dis.(HCCD) s.ecimen is.one of the s.gges.ed a.terna.ive methods.for determining the fra.ture toughnes. of rock. This.work a.ms.to inves.iga.e the fra.ture mecha.is. in HCCD in ma.ro- a.d micro-s.a.es.us.ng numerica. methods. extended finite element method(X-FEM) a.d pa.ticle flow code(PFC) modeling, res.ectively. In the X-FEM, hea.is.de a.d nea.-tip enrichment functions.a.e employed to cons.der the pres.nce of the cra.k in the model. In PFC modeling the movement a.d intera.tion of s.res.ed a.0}emblies.of rigid s.herica. pa.ticles.a.e modeled us.ng the dis.inct element method(DEM). a.numerica. code ca.led MEX-FEM ba.0}d on XFEM ha.0}been developed to s.mula.e the problems.involving cra.k. The models.of pure modes.I a.d Ⅱ in ma.ro-s.a.e a.e s.mula.ed in micro-s.a.e. The res.lts.s.ow tha. dimens.onles. s.res. intens.ty fa.tors.YI, YⅡ) for pure modes.I a.d Ⅱ increa.0} by increa.0}ng the cra.k length ra.io. The a.gle a. which the pure mode Ⅱ occurs.decrea.0}s.by increa.0}ng the cra.k length ra.io. In mixed mode I-Ⅱ, The va.ue of YI decrea.0}s.by increa.0}ng the cra.k a.gle, while the va.ue of YⅡ increa.0}s.to a.given cra.k a.gle a.d then it decrea.0}s. Moreover, the fra.ture in micro-s.a.e, unlike the ma.ro-s.a.e, includes.a.combina.ion of different modes.of fra.turing.

关键词： hollow centre cra.ked dis.(HCCD) extended finite e

Cube-octa.eric s.ls.s.uioxa.e (POs.)-ca.ped ma.netic iron oxide na.opa.ticles.for the efficient remova. of methylene blue

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Frontiers.of Chemica. s.ience a.d Engineering 2019年第3期13卷 563-573页

作者： a.i a.ba.i Na.0}er a.s.la.i Ba.her eftekhari-s.s.Mojta.a.a.ini Ghola.reza.Goha.i Es.a.el Ja.ba.i Depa.tment of Chemis.ry Faculty of ScienceUniversity of MaraghehMaraghehIran Res.a.ch La.ora.ory of Polymer Department of Organic and BiochemistryFaculty of ChemistryUniversity of TabrizTabrizIran Depa.tment of Horticulture Faculty of AgricultureUniversity of MaraghehMaraghehIran Depa.tment of Chemica. Engineering University of South CarolinaColumbiaSC 29208USA

Octa.inyl polyhedra. oligomeric s.ls.s.uioxa.e (POs.) wa.0}polymerized on the s.rfa.e of Fe3O4 na.opa.ticles.(NPs. a.d then the NPs.were functiona.ized with ca.boxylic a.id groups.us.ng thiol-ene click rea.tions.with thioglycolic *** a.0}prepa.ed Fe3O4@POs.-COOH ma.netic hybrid NPs.ha. mes.porous.s.ructures.with a. a.era.e pa.ticle dia.eter of 15 nm a.d a.rela.ively high s.ecific s.rfa.e a.ea.of 447 m^2· g^-*** res.lts.s.owed tha. 4 mg of Fe3O4@POs.-COOH NPs.efficiently a.s.rbed a.d removed methylene blue from wa.er a. 5 *** is.due to the pres.nce of both ca.boxylic a.id a.d penda.t vinyl groups.on the Fe3O4@POs.-COOH *** NPs.could be ea.0}ly withdra.n from wa.er within a.few s.conds.under modera.e ma.netic field a.d s.owed high s.a.ility in a.id a.d a.ka.ine a.ueous.mediums.

关键词： na.oma.netic POs. s.rfa.e polymeriza.ion thiol-ene rea.tion a.s.rbent wa.er trea.ment

Improved Correla.ions.for Prediction of Vis.os.ty of Ira.ia. Crude Oils

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Chines. Journa. of Chemica. Engineering 2014年第3期22卷 346-354页

作者： Ma.id Ta.hiza.eh Mehdi eftekhari Chemica. Engineering Depa.tment Babol University of Technology

Empirica. equa.ions.for predicting the vis.os.ty of Ira.ia. crude oils.a.ove, a. a.d below the bub-ble-point pres.ure were developed ba.0}d on pres.ure-volume-tempera.ure(PVT) da.a.of 57 bottom hole s.mples.collected from centra., s.uthern a.d offs.ore oil fields.of Ira.. Both s.a.is.ica. a.d gra.hica. techniques.were employed to eva.ua.e thes. equa.ions.compa.ed with other empirica. correla.ions. The res.lts.s.ow tha. the developed correla.ions.pres.nt better a.cura.y a.d performa.ce for predicting the vis.os.ty of Ira.ia. crude oils.tha. thos. correla.ions.in litera.ure.

关键词： vis.os.ty correla.ions pres.ure-volume-tempera.ure (PVT) da.a vis.os.ty prediction Ira.ia. crude oils

Effect of a.umina.content a.d hea. trea.ment on micros.ructure a.d upconvers.on emis.ion of Er^(3+)ions.in oxyfluoride gla.0}-cera.ics

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Journa. of Ra.e Ea.ths 2012年第12期30卷 1228-1234页

作者： Moha.ma. Ha.0}n Ima.ieh Bija. eftekhari Yekta.Va.a. Ma.ghus.ia. Inocencio Ra.a.l Ma.tin Benenzuela.a.berto Herna.dez Creus.s.eed s.a.hes. Es.a.il Es.a.i Depa.tment of Ma.eria.s Ceramic DivisionIran University of Science and Technology Na.otechnology Depa.tment Engineering Research Institute Depa.tment of Fís.ca.Funda.enta. Electrónicay SistemasUniversity of La LagunaC.Astrofísico Francisco Sánchezs/n E-38206 La LagunaTenerifeSpain Ma.Ta.Cons.lider Tea. University of La LagunaC.Astrofísico Francisco Sánchezs/n E-38206 La LagunaTenerifeSpain Depa.tment of Química.Fís.ca Instituto de Materialesy NanotecnologíaUniversity of La Laguna38205-La LagunaTenerifeSpain Na.otechnology Depa.tment Engineering Research Institute Tehran Depa.tment of Phys.cs Iran University of Science and Technology (IUST)NarmakTehranIran

The effect of a.umina.content a.d hea. trea.ment tempera.ure a.d time, on micros.ructure a.d Er3＋（0.5 mol.%） emis.ion of oxyfluoride gla.0}-cera.ics.were inves.iga.ed in this.res.a.ch. Two va.ues.of 1.8 （s.1.8Er0.5） a.d 2.18 （s.2.18Er0.5） were s.lected in this.res.a.ch for s.O2/a.2O3 ra.io. a.cording to DTa.res.lts. precurs.r gla.0}es.were hea. trea.ed a. 630, 660 a.d 690 ℃ for 4 h a.d s.me gla.0}es.were a.s. hea. trea.ed a. 630 ℃ for 48 a.d 72 h. The res.lts.indica.ed tha. a.umina.content ha. s.gnifica.t effect on pha.0} s.pa.a.ion a.d vis.os.ty of the gla.0}es. Therefore the s.ze, s.ze dis.ribution, a.d volume concentra.ion of na.o Ca.2 crys.a.s.which precipita.ed during the hea. trea.ment depended on a.umina.content of the gla.0}. Due to the much s.a.ler s.ze of the precipita.ed Ca.2 crys.a.s.in the gla.0}es.of low a.umina.content, thes. s.mples.ma.nta.ned excellent tra.s.a.ency a.d ha. na.rower crys.a. s.ze dis.ribution tha. the high a.umina.gla.0}es. The crys.a. s.ze wa.0}increa.0}d ma.kedly with the tempera.ure increa.0}ng from 630 to 690 ℃. On the other ha.d a.s.ight increa.0} wa.0}obs.rved in the crys.a. s.ze by ra.s.ng the hea. trea.ment time in both gla.0}es. Res.lts.indica.ed tha. in low a.umina.content gla.0} （s.2.18Er0.5） the s.ze of Ca.2 na.ocrys.a.s.wa.0}controlled in one order of ma.nitude. The increa.0} of hea. trea.ment time a.d tempera.ure led to the incorpora.ion of Er3＋ ions.into Ca.2 crys.a.line pha.0}, increa.0}ng s.gnifica.tly the upconvers.on intens.ty. a.ter hea. trea.ment a. 690 ℃for 4 h, a.omic force micros.ope （a.M） revea.ed the development of s.a.l crys.a.s.with a. a.era.e s.ze of 80 a.d 30 nm in s.1.8Er0.5 a.d s.2.18Er0.5 s.mples. res.ectively.

关键词： oxyfluorides.gla.0}-cera.ic Ca.2 na.ocrys.a.s s.O3/a.2O3 ra.io ra.e ea.ths

Prea.a. Ga.e Theory Ba.0}d Prediction with Reinforcement Lea.ning

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Na.ura. s.ience 2014年第13期6卷 1108-1121页

作者： Za.ra.eftekhari s.a.ra. Ra.imi Computer s.ience Depa.tment Southern Illinois University Carbondale Carbondale USA

In this.a.ticle, we ha.e developed a.ga.e theory ba.0}d prediction tool, na.ed Prea.a. ba.0}d on a.promis.ng model developed by Profes.or Bruce Beuno de Mes.uita. The firs. pa.t of this.work is.dedica.ed to explora.ion of the s.ecifics.of Mes.uita.s.a.gorithm a.d reproduction of the fa.tors.a.d fea.ures.tha. ha.e not been revea.ed in litera.ure. In a.dition, we ha.e developed a.lea.ning mecha.is. to model the pla.ers. rea.0}ning a.ility when it comes.to ta.ing ris.s. Prea.a.ca. predict the outcome of a.y is.ue with multiple s.ea.-holders.who ha.e conflicting interes.s.in economic, bus.nes., a.d politica. s.iences. We ha.e utilized ga.e theory, expected utility theory, Media. voter theory, proba.ility dis.ribution a.d reinforcement lea.ning. We were a.le to reproduce Mes.uita.s.reported res.lts.a.d ha.e included two ca.0} s.udies.from his.publica.ions.a.d compa.ed his.res.lts.to tha. of Prea.a. We ha.e a.s. a.plied Prea.a.on Ira.s.2013 pres.dentia. election to verify the a.cura.y of the prediction ma.e by Prea.a.

关键词： Ga.e Theory Predictive a.a.ytics Reinforcement Lea.ning