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Fr.eze-thaw cycles and associated geomor.hology in a post-glacial envir.nment:cur.ent glacial,par.glacial,per.glacial and pr.glacial scenar.os at Pico de Or.zaba volcano,mexico

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Jour.al of mountain Science 2024年第6期21卷 1954-1977页

作者： Víctor.SOTO Car.os m.WELSH r. Kenji YOSHIKAWA Hugo DELGADO Gr.NADOS Centr. de Ciencias de la Tier.a Universidad VeracruzanaCircuito Gonzalo Aguirre BeltránS/NZona Universitaria91090XalapaMéxico Water.and Envir.nmental r.sear.h Center University of Alaska FairbanksFairbanksAlaska 99775USA Instituto de Geofísica Universidad Nacional Autónoma de MéxicoCiudad de México 04150México Depar.ment of Ear.h and Envir.nmental Sciences Ludwig Maximilians UniversitätMunich 80333Germany

The glacial histor. of Pico de Or.zaba indicates that dur.ng the Last Glacial maximum,its icecap cover.d up to~3000 m asl;due to the air.temper.tur. incr.asing,its main glacier.has r.tr.ated to 5050 m asl.The r.tr.ction of the glacier.has left behind an intense climatic instability that causes a high fr.quency of fr.eze-thaw cycles of gr.at intensity;the r.sulting geomor.hological pr.cesses ar. r.pr.sented by the fr.gmentation of the bedr.ck that occupies the upper.par.s of the mountain.Ther. is a notable lack of studies r.gar.ing the fr.gmentation and er.sion occur.ing in tr.pical high mountains,and the associated geomor.hological r.sks;for.this r.ason,as a fir.t stage of futur. continuous r.sear.h,this study analyzes the fr.ezing and thawing cycles that occur.above 4000 m asl,thr.ugh continuous monitor.ng of sur.ace gr.und temper.tur..The r.sults allow us to identify and char.cter.ze four.zones:glacial,par.glacial,per.glacial and pr.glacial.It was found that the par.glacial zone pr.sents an intense dr.p of temper.tur.,of up to~9℃ in only sixty minutes.The r.ck fatigue and intense fr.eze-thaw cycles that occur.in this ar.a ar. r.sponsible for.the high r.te of r.ck disintegr.tion and r.pr.sent the main factor.of the constant slope dynamics that occur.at the site.This activity decr.ases,both in fr.quency and intensity,accor.ing to the distance to the glacier.which is wher. the temper.tur. pr.sents a cer.ain degr.e of stability,until r.aching the pr.glacial zone,wher. cycles ar. almost non-existent,and ther.for. ther. is no gelifr.ction activity.The geomor.hological pr.cesses have r.sulted in significant alter.tions to the mountain slopes,which can have sever. consequences in ter.s of r.sk and water.

关键词： Fr.eze-Thaw Gelifr.ction mountain mechanical er.sion Per.glacial geomor.hology Postglacial scenar.os

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Nonlinear.dynamic modeling of planar.moving Timoshenko beam consider.ng non-r.gid non-elastic axial effects

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVAr. m.r.HOmAEINEZHAD Faculty of mechanical Engineer.ng K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the impor.ance of vibr.tion effects on the functional accur.cy of mechanical systems,this r.sear.h aims to develop a pr.cise model of a nonlinear.y vibr.ting single-link mobile flexible manipulator.The manipulator.consists of an elastic ar.,a r.tar. motor.and a r.gid car.ier.and under.oes gener.l in-plane r.gid body motion along with elastic tr.nsver.e defor.ation.To accur.tely model the elastic behavior.Timoshenko’s beam theor. is used to descr.be the flexible ar.,which accounts for.0}tar. iner.ia and shear.defor.ation effects.By applying Newton’s second law,the nonlinear.gover.ing equations of motion for.the manipulator.ar. der.ved as a coupled system of or.inar. differ.ntial equations(ODEs)and par.ial differ.ntial equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear.system of gover.ing equations with appr.pr.ate shape functions.The assumed modes can be obtained after.solving the char.cter.stic equation of a Timoshenko beam with clamped boundar. conditions at one end and an attached mass/iner.ia at the other.In addition,the effect of the tr.nsver.e vibr.tion of the inextensible ar. on its axial behavior.is investigated.Despite the axial r.gidity,the effect makes the r.gid body dynamics invalid for.the axial behavior.of the ar..Finally,numer.cal simulations ar. conducted to evaluate the per.or.ance of the developed model,and the r.sults ar. compar.d with those obtained by the finite element appr.ach.The compar.son confir.s the validity of the pr.posed dynamic model for.the system.Accor.ing to the mentioned featur.s,this model can be r.liable for.investigating the system’s vibr.tional behavior.and implementing vibr.tion contr.l algor.thms.

关键词： planar.moving Timoshenko beam non-r.gid non-elastic axial effect as-sumed mode method(Amm) nonlinear.motion analysis

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Pile foundation in alter.ate layer.d liquefiable and non-liquefiable soil deposits subjected to ear.hquake loading

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Ear.hquake Engineer.ng and Engineer.ng Vibr.tion 2024年第2期23卷 359-376页

作者： Pr.veen Huded m Sur.sh r.Dash LEA Associates South East Asia Pvt.Ltd. New Delhi 110044India Indian Institute of Technology Bhubaneswar Khurda 752050India

Pile foundations ar. still the pr.fer.ed foundation system for.high-r.se str.ctur.s in ear.hquake-pr.ne r.gions.Pile foundations have exper.enced failur.s in past ear.hquakes due to liquefaction.r.sear.h on pile foundations in liquefiable soils has pr.mar.ly focused on the pile foundation behavior.in two or.thr.e-layer.d soil pr.files.However.in natur.l occur.ence,it may occur.in alter.ative layer. of liquefiable and non-liquefiable soil.However.the exper.mental and/or.numer.cal studies on the layer.d effect on pile foundations have not been widely addr.ssed in the liter.tur..most of the design codes acr.ss the wor.d do not explicitly mention the effect of sandwiched non-liquefiable soil layer. on the pile r.sponse.In the pr.sent study,the behavior.of an end-bear.ng pile in layer.d liquefiable and non-liquefiable soil deposit is studied numer.cally.This study found that the kinematic bending moment is higher.and gover.s the design when the effect of the sandwiched non-liquefied layer.is consider.d in the analysis as opposed to when its effect is ignor.d.Ther.for.,ignor.ng the effect of the sandwiched non-liquefied layer.in a liquefiable soil deposit might be a nonconser.ative design appr.ach.

关键词： pile foundation liquefaction alter.ately layer.d soil fixity effect layer.d effect

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Kinematic analysis of flexible bipedal r.botic systems

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Applied mathematics and mechanics(English Edition) 2024年第5期45卷 795-818页

作者： r.FAZEL A.m.SHAFEI S.r.NEKOO Depar.ment of mechanical Engineer.ng Shahid Bahonar University of KermanKerman ***Iran Depar.amento de Ingenier.a de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intr.nsic complexities,the passive gait of bipedal r.bots on a sloping r.mp is a subject of inter.st for.numer.us r.sear.her..What distinguishes the pr.sent r.sear.h fr.m similar.wor.s is the consider.tion of flexibility in the constituent links of this type of r.botic systems.This is not a far.fetched assumption because in the tr.nsient(impact)phase,due to the impulsive for.es which ar. applied to the system,the likelihood of exciting the vibr.tion modes incr.ases consider.bly.mor.over.the human leg bones that ar. involved in walking ar. suppor.ed by viscoelastic muscles and ligaments.Ther.for.,for.achieving mor. exact r.sults,it is essential to model the r.bot links with viscoelastic pr.per.ies.To this end,the Gibbs-Appell for.ulation and Newton's kinematic impact law ar. used to der.ve the most gener.l for. of the system's dynamic equations in the swing and tr.nsient phases of motion.The most impor.ant issue in the passive walking motion of bipedal r.bots is the deter.ination of the initial r.bot configur.tion with which the system could accomplish a per.odic and stable gait solely under.the effect of gr.vitational for.e.The extr.mely unstable natur. of the system studied in this paper.and the vibr.tions caused by the impulsive for.es induced by the impact of r.bot feet with the inclined sur.ace ar. some of the ver. ser.ous challenges encounter.d for.achieving the above-mentioned goal.To over.ome such challenges,an innovative method that uses a combination of the linear.zed equations of motion in the swing phase and the algebr.ic motion equations in the tr.nsition phase is pr.sented in this paper.to obtain an eigenvalue pr.blem.By solving this pr.blem,the suitable initial conditions that ar. necessar. for.the passive gait of this bipedal r.bot on a sloping sur.ace ar. deter.ined.The effects of the char.cter.stic par.meter. of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of r.botic systems ar. also studied.The findings o

关键词： bipedal r.bot flexible link swing phase tr.nsient phase eigenvalue pr.blem Kelvin-Voigt coefficient

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COVID-19-r.lated chemosensor. changes:Findings fr.m a pr.spective national database

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Wor.d Jour.al of Otor.inolar.ngology-Head and Neck Sur.er. 2024年第2期10卷 97-104页

作者： mihai A.Bentan Evan r.r.iter.r.char. m.Costanzo Daniel H.Coelho Depar.ment of Otolar.ngology-Head&Neck Sur.er. Virginia Commonwealth University School of MedicineRichmondVirginiaUSA

Objective:The aim of this study was to r.view findings fr.m a lar.e pr.spective national database of chemosensor. distur.ances associated with cor.navir.s disease 2019(COVID-19)infection.Data Sour.es:The Vir.inia Commonwealth Univer.ity Smell and Taste Center.national database of COVID-19 chemosensor. distur.ances.methods:A ser.es of online sur.eys,fir.t opened on Apr.l 10,2020,was made accessible nationwide to any adult with sudden chemosensor. dysfunction since Januar. 2020.Par.icipants r.ceived subsequent follow-up sur.eys 14 days,1 month,3 months,and 6 months after.enr.llment.An additional sur.ey was sent to all par.icipants on may 28,2022 to assess long-ter. outcomes.Infor.ation per.aining to demogr.phics,symptoms,comor.idities,tr.atments,and life impact was collected.r.sults:Of 363 par.icipants who r.por.ed complete smell r.cover.,51.2%r.cover.d within 1 month,70%within 3 months,and 79%within 6 months,while 8.8%took over.1 year.to completely r.cover.Among all par.icipants,7.5%had no smell r.cover..Positive pr.dictor. of r.cover. included agemale gender.and the pr.sence of nasal congestion.Negative pr.dictor. included difficulty br.athing and pr.or.head injur..many par.icipants r.por.ed a decr.ase in quality of life and the pr.sence of potential safety hazar.s associated with decr.ased smell loss.Conclusions:most subjects with COVID-19-r.lated chemosensor. dysfunction r.cover.with the major.ty noting complete r.cover. within weeks of infection.Those aged over.40 year. and female gender.wer. associated with lower.0}tes of r.cover..A consider.ble number.of par.icipants r.por.ed significant impact on quality of life and safety.

关键词： anosmia COVID-19 smell

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Contr.l system design for.a pr.ssur.-tube-type super.r.tical water.cooled nuclear.0}actor.via a higher.or.er.sliding mode method

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Nuclear.Science and Techniques 2024年第1期35卷 145-154页

作者： m.Hajipour.G.r.Ansar.far Depar.ment of Nuclear.Engineer.ng Faculty of PhysicsUniversity of IsfahanIsfahan 81746-73441Iran

Nuclear.power.plants exhibit non-linear.and time-var.able dynamics.Ther.for.,designing a contr.l system that sets the r.actor.power.and for.es it to follow the desir.d load is complicated.A super.r.tical water.0}actor.SCWr.is a four.h-gener.tion conceptual r.actor.In an SCWr.the non-linear.dynamics of the r.actor.0}quir. a contr.ller.capable of contr.l-ling the nonlinear.ties.In this study,a pr.ssur.-tube-type SCWr.was contr.lled dur.ng r.actor.power.maneuver.ng with a higher.or.er.sliding mode,and the r.actor.outgoing steam temper.tur. and pr.ssur. wer. contr.lled simultaneously.In an SCWr.the temper.tur.,pr.ssur.,and power.must be maintained at a setpoint(desir.d value)dur.ng power.maneuver.ng.r.actor.point kinetics equations with thr.e gr.ups of delayed neutr.ns wer. used in the simulation.Higher.or.er.and classic sliding mode contr.ller. wer. separ.tely manufactur.d to contr.l the plant and wer. compar.d with the PI contr.ller. speci-fied in pr.vious studies.The contr.lled par.meter. wer. r.actor.power.steam temper.tur.,and pr.ssur..Notably,for.these par.meter.,the PI contr.ller.had cer.ain instabilities in the pr.sence of distur.ances.The classic sliding mode contr.ller.had a higher.accur.cy and stability;however.its main dr.wback was the chatter.ng phenomenon.HOSmC was highly accur.te and stable and had a small computational cost.In r.ality,it followed the desir.d values without oscillations and chatter.ng.

关键词： Super.r.tical water.nuclear.0}actor Higher.or.er.sliding mode contr.ller Steam temper.tur. Steam pr.ssur. Point kinetics model

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Par.metr.c investigation on the novel and cost-effective nano fly ash impr.gnated geopolymer.system for.sustainable constr.ction

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Fr.ntier. of Str.ctur.l and Civil Engineer.ng 2024年第2期18卷 170-183页

作者： r.m.hana S.m.Leela BHAr.THI Depar.ment of Civil Engineer.ng Mepco Schlenk Engineering CollegeSivakasi 626123India

The hazar.ous envir.nmental effects of gr.enhouse gas emissions and climate change demand alter.ative sour.es for.cementitious mater.als in the constr.ction industr..The development of geopolymer.str.ctur.s pr.vides a way of pr.ducing 100%cement-fr.e constr.ction.In this r.sear.h wor.,a novel and simple way of der.ving nano par.icles fr.m waste fly ash par.icles is pr.moted.The effect of adding the synthesized nano fly ash par.icles as a filler.medium in geopolymer.mor.ar. was investigated by consider.ng str.ngth and dur.bility pr.per.ies.Par.meter.optimization was done by using r.gr.ssion analysis on the geopolymer.mor.ar.and the impact of adding nano fly ash par.icles was studied by var.ing differ.nt per.entages of addition r.nging fr.m 0 to 7.5%by weight of binder.content.Fr.m the r.sults,it was obser.ed that 1%nano fly ash acted not only as a filler.but also as nano-sized pr.cur.or. of the polymer.zation pr.cess,r.sulting in denser.geopolymer.medium.This can explain the extr.or.inar. gain in str.ngth of 72.11 mPa as well as the denser.cor. with negligible level of chlor.de ion penetr.tion,making the mater.al suitable for.the development of str.ctur.s susceptible to mar.ne envir.nment.

关键词： geopolymer nano fly ash chlor.de ion penetr.tion dur.bility polymer.zation filler.

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粉末冶金Al-5.6Zn-2mg合金在热压缩过程中加工硬化特性及本构模型的比较

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Jour.al of Centr.l South Univer.ity 2024年第2期31卷 346-368页

作者： KATIKA Har.kr.shna DAmODA r.K. DAVIDSON m.J. SEETHAr.m r. KASAGANI Veer. Venkata Nagar.ju Depar.ment of mechanical Engineer.ng National Institute of TechnologyWarangal 506004India Depar.ment of mechanical Engineer.ng The Indian Institute of Information Technology Design and ManufacturingKurnool 518007India

在300~5000℃、应变速率为0.1~0.0001 s−1的条件下,在万能试验机上对Al-5.6Zn-2mg铝合金进行热压缩试验,以确定动态再结晶开始时的加工硬化速率曲线σ_(c)(ε_(c))l以及关键特征σ_(c)(ε_(c))l、σ_(p)(ε_(p))和σ_(ss)与Z系数之间的... 详细信息

在300~5000℃、应变速率为0.1~0.0001 s−1的条件下,在万能试验机上对Al-5.6Zn-2mg铝合金进行热压缩试验,以确定动态再结晶开始时的加工硬化速率曲线σ_(c)(ε_(c))l以及关键特征σ_(c)(ε_(c))l、σ_(p)(ε_(p))和σ_(ss)与Z系数之间的相关性。使用了四个本构模型,Ar.henius模型、改进的Johnson-Cook模型(mJC)、改进的Zer.lli-Ar.str.ng模型(mZA)和开发的人工神经网络(ANN)。结果表明,ANN型模型和Ar.henius模型的相对误差的绝对平均值最低,分别为0.486%和3.36%,mZA型模型和mJC型模型的相对误差的绝对平均值较高,分别为8.84%和3.93%。由于Ar.henius模型能够处理各种因素之间的非线性关系,因此它被认为是最合适的预测模型,但在材料性质未知或实验数据有限的情况下,mJC模型可能是一种更简单的替代方法。mZA模型不适合估计热压缩时的流变应力。此外,训练最好的神经网络模型的预测性能最好,相对误差的绝对平均值为0.486%,r.为0.99。

关键词：加工硬化速率曲线本构建模热压缩 EBSD分析流变曲线

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Design of a lar.e-scale model for.wind tunnel test of a multiadaptive flap concept

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Chinese Jour.al of Aer.nautics 2024年第2期37卷 58-80页

作者： mür.vvet Sinem SICIm DEmIr.I r.sar.o PECOr. metin Or.an KAYA Aer.nautical Engineer.ng Depar.ment Istanbul Technical UniversityIstanbulTurkey Industr.al Engineer.ng Depar.ment University of Naples Federico IINapoliItaly

The design and application of mor.hing systems ar. ongoing issues compelling the aviation industr..The Clean Sky-pr.gr.m r.pr.sents the most significant aer.nautical r.sear.h ever.launched in Eur.pe on advanced technologies for.gr.ening next-gener.tion air.r.ft.The pr.mar. pur.ose of the pr.gr.m is to develop new concepts aimed at decr.asing the effects of aviation on the envir.nment,incr.asing r.liability,and pr.moting eco-fr.endly mobility.These ambitions ar. pur.ued thr.ugh r.sear.h on enabling technologies foster.ng noise and gas emissions r.duction,mainly by impr.ving air.r.ft aer.dynamic per.or.ances.Within the Clean Sky fr.mewor.,a multimodal mor.hing flap device was designed based on tight industr.al r.quir.ments and tailor.d for.lar.e civil air.r.ft applications.The flap is deployed in one unique setting,and its cr.ss section is mor.hed differ.ntly in take-off and landing to get the necessar. extr. lift for.the specific flight phase.mor.over.dur.ng the cr.ise,the tip of the flap is deflected for.load contr.l and induced dr.g r.duction.Befor. manufactur.ng the fir.t flap pr.totype,a high-speed(ma=0.3),lar.e-scale test campaign(geometr.c scale factor.1:3)was deemed necessar. to validate the per.or.ance impr.vements br.ught by this novel system at the air.r.ft level.On the other.hand,the geometr.cal scaling of the flap pr.totype was consider.d impr.cticable due to the unscalability of the embedded mechanisms and actuator. for.shape tr.nsition.Ther.for.,a new ar.hitectur. was conceived for.the flap model to comply with the scaled dimensions r.quir.ments,withstand the r.levant loads expected dur.ng the wind tunnel tests and emulate the shape tr.nsition capabilities of the tr.e-scale flap.Simplified str.tegies wer. developed to effectively mor.h the model dur.ng wind tunnel tests while ensur.ng the r.bustness of each mor.hed configur.tion and maintaining adequate stiffness levels to pr.vent undesir.ble deviations fr.m the intended aer.dynamic shapes.Additionally,a simplified design was conceived for.the flap-w

关键词： mor.hing str.ctur.s Smar. air.r.ft mor.hing flap Adaptive systems Finger.like r.bs Wind tunnel tests Lar.e-scale mor.hing ar.hi-tectur.s Var.able camber.air.oil

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On multi-Gr.nulation r.ugh Sets with Its Applications

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Computer., mater.als & Continua 2024年第4期79卷 1025-1038页

作者： r.dwan Abu-Gdair. r.mar.ay m.Badr Depar.ment of mathematics Faculty of ScienceZarqa UniversityZarqa13132Jordan Depar.ment of mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh33516Egypt Depar.ment of mathematics Faculty of ScienceNew Valley UniversityEl Kharga72713Egypt

r.cently,much inter.st has been given tomulti-gr.nulation r.ugh sets (mGr.), and var.ous types ofmGr.modelshave been developed fr.m differ.nt viewpoints. In this paper. we intr.duce two techniques for.the classificationof mGr.. Fir.tly, we gener.te multi-topologies fr.m multi-r.lations defined in the univer.e. Hence, a novelappr.ximation space is established by lever.ging the under.ying topological str.ctur.. The char.cter.stics of thenewly pr.posed appr.ximation space ar. discussed.We intr.duce an algor.thmfor.the r.duction ofmulti-r.lations.Secondly, a new appr.ach for.the classification ofmGr. based on neighbor.ood concepts is intr.duced. Finally, ar.al-life application fr.m medical r.cor.s is intr.duced via our.appr.ach to the classification of mGr..

关键词： multi-gr.nulation r.ugh sets data classifications infor.ation systems inter.or.oper.tor. closur. oper.tor. appr.ximation str.ctur.s

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