b Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, Chinaa r t i c l e i n f oArticle history:Received 16 May 2011Received in revised form 16 February 2012Accepted 28 May 2012Keywords:Sliding zoneUnsaturated soilsMatric suctionCreep behaviorBurgers modela b s t r a c tThe mechanical behavior of sliding zone soils […]

Elasto-Plastic Stresses in ThickWalled CylindersIn the optimal design of a modern gun barrel, there are two main objectives to beachieved: increasing its strength-weight ratio and extending its fatigue life. This can becarried out by generating a residual stress field in the barrel wall, a process known asautofrettage. It is often necessary to machine the autofrettaged […]

KeithPriestley,DanMcKenzie∗DepartmentofEarthSciences,BullardLabs,MadingleyRoad,CambridgeCB30EZ,UKarticleinfoabstractArticlehistory:Received3February2013Receivedinrevisedform16July2013Accepted10August2013Availableonline25September2013Editor:P.ShearerKeywords:surfacewavetomographymantletemperaturelithosphericthicknessshearwaveattenuationmantleviscositySurfacewavetomography,usingthefundamentalRayleighwavevelocitiesandthoseofhighermodesbetween1and4andperiodsbetween50and160s,isusedtoimagestructureswithahorizontalresolutionof∼۲۵۰kmandaverticalresolutionof∼۵۰kmtodepthsof∼۳۰۰kminthemantle.Anewmodel,PM_v2_2012,obtainedfrom3×۱۰۶seismograms,agreeswellwithearlierlowerresolutionmodels.ItiscombinedwithtemperatureestimatesfromoceanicplatemodelsandwithpressureandtemperatureestimatesfromthemineralcompositionsofgarnetperidotitenodulestogenerateanumberofestimatesofSV(P,T)basedongeophysicalandpetrologicalobservationsalone.Thesearethenusedtoestimatetheunrelaxedshearmodulusanditsderivativeswithrespecttopressureandtemperature,whichagreereasonablywithvaluesfromlaboratoryexperiments.Athightemperaturesrelaxationoccurs,causingtheshearwavevelocitytodependonfrequency.ThisbehaviourisparameterisedusingaviscositytoobtainaMaxwellrelaxationtime.Therelaxationbehaviourisdescribedusingadimensionlessfrequency,whichdependsonanactivationenergyEandvolumeVa.ThevaluesofEandVaobtainedfromthegeophysicalmodelsagreewiththosefromlaboratoryexperimentsonhightemperaturecreep.Theresultingexpressionsarethenusedtodeterminethelithosphericthicknessfromtheshearwavevelocityvariations.Theresolutionisimprovedbyaboutafactoroftwowithrespecttoearliermodels,andclearlyresolvesthethicklithospherebeneathactiveintracontinentalbeltsthatarenowb

eingshortened.Thesameexpressionsallowthethreedimensionalvariationsoftheshearwaveattenuationandviscositytobeestimated.©۲۰۱۳ElsevierB.V.Allrightsreserved.۱٫IntroductionTheassociationofreducedshearwavevelocityVs,increasedattenuationandreducedviscosityintheEarth’suppermantlehasbeenknownforalmostninetyyears(seeGutenberg,1959,p.76).Theseeffectsaremostobviousintheasthenosphere,wherethemantletemperatureapproachesthemeltingtemperature.Fig.1ashowsatypicalsteadystatecontinentalgeotherm.Thelayerclosetothesurface,whereheatistransportedbyconductionalone,isknownasthemechanicalboundarylayer(MBL).Itisunderlainbyathermalboundarylayer(TBL)thatformspartoftheconvectivecirculationoftheuppermantle,andwhichsuppliesheattothebaseoftheMBL.Atgreaterdepthsthetemperaturegradientintheconvectiveinteriorisisentropic.Nodiscontinuitiesineitherthetemperatureoritsgradientcanoccuranywhere.Aconvenientwaytodescribeageothermisintermsoftheequivalentlithosphericthickness,definedasthedepthatwhichtheextrapolatedconduc-tivegeothermwouldintersectthatoftheconvectiveinterior.ThisdefinitionwasusedbyPriestleyandMcKenzie(2006),hereafter*Correspondingauthor.Tel.:+441223337191.E-mailaddress:mckenzie@madingley.org(D.McKenzie).PM6,andisalsousedhere.Itisthenthesameastheplatethick-nessusedtoparameterisethethermalstructureofoceanicplates(seeCrosbyetal.,2006).AsFig.1ashows,thebaseofthelitho-spheredefinedinthiswaylieswithinthethermalboundarylayer,anddoesnotcorrespondtoanyphysicalboundary.Furthermorethetemperatureofthatpartofthethermalboundarylayerthatliesbelowthebaseofthelithosphereislowerthanthatoftheisentropicinterior.Figs.1b–۱eshowtwotemperatureprofilesfromwesternAfricaandtheirbestfittinggeotherms,togetherwiththeirSVprofiles.Thereisnostepinthevelocityprofilescorrespondingtothebaseofthelithosphere تعداد صفحه : ۱۴تکه هایی از متن ترجمه فارسی به عنوان نمونه :رابطه سرعت برشی,درجه حرارت ،روابط کاهندگی و ویسکوزیته در قسمت کم عمق از گوشتهچکیده:

گرایش همگانی عنوان: تحلیلِ انتقادیِ گفتمانِ فیلمِ ایرانیِ«یه حبه قند»اثرِ رضا میرکریمی استاد راهنما: دکتر حسن بشیرنژاد استاد مشاور: دکترعلی سلیمی‌خورشیدی تابستان ۱۳۹۳ (در فایل دانلودی نام نویسنده موجود است) فهرست مطالب عنوان صفحه چکیده فارسی. ۱ فصل اوّل:کلیات پژوهش ۱-۱٫ مقدمه. ۳ ۱-۲٫ بیان مسئله. ۶ ۱-۳٫ پرسش‌های تحقیق ۷ ۱-۴٫ […]