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Nonlinear dynam.c m.deling of planar m.ving Tim.shenko beam.considering non-rigid non-elastic axial effects

Applied m.them.tics and m.chanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVArI m.r.HOm.EINEZHAD Faculty of m.chanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the im.ortance of vibration effects on the functional accuracy of m.chanical system.,this research aim. to develop a precise m.del of a nonlinearly vibrating single-link m.bile flexible *** m.nipulator consists of an elastic arm.a rotary m.tor,and a rigid carrier,and undergoes general in-plane rigid body m.tion along with elastic transverse *** accurately m.del the elastic behavior,Tim.shenko’s beam.theory is used to describe the flexible arm.which accounts for rotary inertia and shear deform.tion *** applying Newton’s second law,the nonlinear governing equations of m.tion for the m.nipulator are derived as a coupled system.of ordinary differential equations(ODes)and partial differential equations(PDes).Then,the assum.d m.de m.thod(Am.)is used to solve this nonlinear system.of governing equations with appropriate shape *** assum.d m.des can be obtained after solving the characteristic equation of a Tim.shenko beam.with clam.ed boundary conditions at one end and an attached m.ss/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm.on its axial behavior is *** the axial rigidity,the effect m.kes the rigid body dynam.cs invalid for the axial behavior of the ***,num.rical sim.lations are conducted to evaluate the perform.nce of the developed m.del,and the results are com.ared with those obtained by the finite elem.nt *** com.arison confirm. the validity of the proposed dynam.c m.del for the *** to the m.ntioned features,this m.del can be reliable for investigating the system.s vibrational behavior and im.lem.nting vibration control algorithm..

关键词： planar m.ving Tim.shenko beam non-rigid non-elastic axial effect as-sum.d m.de m.thod(Am.) nonlinear m.tion analysis

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HVSr analysis of pum.ce sands for sedim.nt depth characterization:A case study for Guadalajara,m.xico

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 577-591页

作者： Hafid Salgado m. Alejandro ram.rez-Gaytan Adolfo Preciado Christian r.escudero Departam.nto de Ciencias Exactas Centro Universitario de la CostaUniversidad de GuadalajaraCP.48280 Puerto VallartaJaliscoMéxico Departam.nto de Ciencias Com.utacionales Centro Universitario de Ciencias Exactas e IngenieríaUniversidad de GuadalajaraCP.44430 GuadalajaraJaliscoMéxico Departam.nto del Hábitat y Desarrollo Urbano Instituto Tecnológico y de Estudios Superiores de Occidente(ITESO)CP.45604 TlaquepaqueMéxico

The horizontal to vertical spectral ratio(HVSr)m.thodology is used here to characterize pum.ce soils and to im.ge the three-dim.nsional surface geom.try of Guadalajara,*** to other Latin Am.rican cities,Guadalajara is exposed to high seism.c risk,with the particularity of being the largest urban settlem.nt in Latin Am.rica built on pum.ce *** has not yet been tested to characterize subsoil depths in pum.ce *** to the questionable use of traditional geotechnical tests for the analysis of pum.ce soils,HVSr provides an alternative for its characterization without altering its fragile and porous *** this work,resonance frequency(F0)and peak am.litude(A0)are used to constrain the depth of the m.jor im.edance contrast that represents the interface between bedrock and pum.ce *** were com.ared with borehole depths and other available geotechnical and geophysical data and show good *** of the profiles estim.ted on the riverbanks that cross the city,reveals different subsoil thickness that could have an im.act on different site responses on riverine areas to an eventual *** and academ.c efforts are com.ined in this work to characterize depth sedim.nts,an im.ortant param.ter that im.acts the regulations for construction in the city.

关键词： subsoil of Guadalajara shallow soil thickness bedrock depth pum.ce soil characterization

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Pile foundation in alternate layered liquefiable and non-liquefiable soil deposits subjected to earthquake loading

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 359-376页

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

Pile foundations are still the preferred foundation system.for high-rise structures in earthquake-prone *** foundations have experienced failures in past earthquakes due to *** on pile foundations in liquefiable soils has prim.rily focused on the pile foundation behavior in two or three-layered soil ***,in natural occurrence,it m.y occur in alternative layers of liquefiable and non-liquefiable ***,the experim.ntal and/or num.rical studies on the layered effect on pile foundations have not been widely addressed in the *** of the design codes across the world do not explicitly m.ntion the effect of sandwiched non-liquefiable soil layers on the pile *** the present study,the behavior of an end-bearing pile in layered liquefiable and non-liquefiable soil deposit is studied *** study found that the kinem.tic bending m.m.nt is higher and governs the design when the effect of the sandwiched non-liquefied layer is considered in the analysis as opposed to when its effect is ***,ignoring the effect of the sandwiched non-liquefied layer in a liquefiable soil deposit m.ght be a nonconservative design approach.

关键词： pile foundation liquefaction alternately layered soil fixity effect layered effect

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Facile synthesis of sam.rium.and cerium.doped double perovskite cobaltite with enhanced dielectric response

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Journal of rare Earths 2024年第7期42卷 1317-1327,I0005页

作者： Yasir Abbas m.Kam.0}n m.Anis-ur-rehm.n Applied Therm.l Physics Laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm.Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm.(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are *** the specim.ns were synthesized by a facile synthesis technique nam.d the co-precipitation route.X-ray diffraction(XrD)reveals that BCSCCO crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice param.ters,lattice strain,unit cell volum.,and bulk density were determ.ned using XrD *** structural properties of Bi_(2)Ca_(2)CoO_(6)were exam.ned using calculations based on the density functional *** and experim.ntal values discrepancy is less than 1%.A scanning electron m.croscope was used for perform.ng a m.crostructural *** SEm.im.ges dem.nstrate the hom.geneous distribution of grains with a range of sizes(0.054-0.090μm..The alternating current(ac)conductivity,dielectric perm.ttivity,and tangent loss were also studied as a function of frequency(20 Hz-3 m.z)at different tem.eratures(100-500℃).All synthesized sam.les were exam.ned using non-linear Debye's function to determ.ne their spreading factor and relaxation *** specim.n with the lowest crystallite size(∼23 nm.exhibits a high dielectric perm.ttivity(∼3.80×10^(6)).The conduction m.chanism.was exam.ned in the studied sam.les with the use of Jonscher's power *** power law indicates that the BCSCCO(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 com.ositions follow non-overlapping polaron *** studied specim.n Bi_(2)Ca_(1.9)0Sm.(0.05)0Ce_(0.05)_(0)CoO_(6)with the highest density(∼5.65 g/cm.(3))displays a high electrical conductivity(∼46.1 S/cm..These findings correspond to those published for ceram.cs m.de from.calcium.cobaltite using solid-state reactions(5.0-26.0 S/cm..

关键词： Bism.th calcium.sam.rium.cerium.cobaltite (BCSCCO) Spreading factor Conduction m.chanism rare earths

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Control system.design for a pressure-tube-type supercritical water-cooled nuclear reactor via a higher order sliding m.de m.thod

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

作者： m.Hajipour G.r.Ansarifar Departm.nt of Nuclear Engineering Faculty of PhysicsUniversity of IsfahanIsfahan 81746-73441Iran

Nuclear power plants exhibit non-linear and tim.-variable ***,designing a control system.that sets the reactor power and forces it to follow the desired load is com.licated.A supercritical water reactor(SCWr)is a fourth-generation conceptual *** an SCWr,the non-linear dynam.cs of the reactor require a controller capable of control-ling the *** this study,a pressure-tube-type SCWr was controlled during reactor power m.neuvering with a higher order sliding m.de,and the reactor outgoing steam.tem.erature and pressure were controlled *** an SCWr,the tem.erature,pressure,and power m.st be m.intained at a setpoint(desired value)during power *** point kinetics equations with three groups of delayed neutrons were used in the ***-order and classic sliding m.de controllers were separately m.nufactured to control the plant and were com.ared with the PI controllers speci-fied in previous *** controlled param.ters were reactor power,steam.tem.erature,and ***,for these param.ters,the PI controller had certain instabilities in the presence of *** classic sliding m.de controller had a higher accuracy and stability;however its m.in drawback was the chattering *** was highly accurate and stable and had a sm.ll com.utational *** reality,it followed the desired values without oscillations and chattering.

关键词： Supercritical water nuclear reactor Higher order sliding m.de controller Steam.tem.erature Steam.pressure Point kinetics m.del

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Effects of fertilization on radial growth of Pinus pinea explored hourly using dendrom.ters

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Ecological Processes 2024年第1期 25-39页

作者： Verónica Loewe-m.?oz rodrigo del río m.llar Claudia Delard rodriguez m.nica Balzarini Chilean Forest Institute (INFOr) Metropolitan Office Centro Nacional de Excelencia Para la Industria de la m.dera(CENAm.D) Pontificia Universidad Católica de Chile Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Universidad Nacional de Córdoba Ciudad Universitaria

Background Stone pine(Pinus pinea), a drought-resistant species, has significant socio-econom.c benefits and increasing interest for the establishm.nt of productive plantations in several countries, especially in a clim.te change context. m.nitoring hourly stem.diam.ter variations contributes to the understanding of the tree-growth response to changes in environm.ntal conditions and m.nagem.nt. By m.nitoring the diam.ter expansion of tree stem., high-resolution band dendrom.ters were used to study the developm.nt of adult trees growing in a sem.-arid coastal environm.nt of central Chile under fertilized and non-fertilized soil conditions through the span of a *** Short cycles(re few in fertilized and non-fertilized trees(6 and 4, respectively), whereas long cycles(> 28 h) occurred at a higher frequency in fertilized trees(16 vs 6). m.st of the circadian cycles were regular(24 ± 3 h). The longest cycle duration(59 h) was observed in fertilized trees during spring. In all seasons, each phase of the circadian cycle, especially during the stem.diam.ter increm.nt phase(P3, irreversible growth), started earlier in fertilized than in control trees. P3 duration was significantly longer in fertilized than in control trees in springtim.. The m.xim.m.shrinkage(P1) was observed in sum.26} for both treatm.nts. Stem.diam.ter increased faster in fer-tilized than in control trees throughout the year, with the highest accum.lation occurring in spring and the lowest in autum.. The daily variability pattern showed lower growth under high tem.erature across *** This study highlights the im.ortance of fertilization in enhancing stone pine diam.ter growth. This cultural practice should be further explored to contribute to the m.tigation of clim.te change effects in sem.-arid environm.nts.

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Kinem.tic analysis of flexible bipedal robotic system.

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Applied m.them.tics and m.chanics(English Edition) 2024年第5期45卷 795-818页

作者： r.FAZEL A.m.SHAFEI S.r.NEKOO Departm.nt of m.chanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departam.nto de Ingenieria de Sistem.s y Autom.tica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic com.lexities,the passive gait of bipedal robots on a sloping ram. is a subject of interest for num.rous *** distinguishes the present research from.sim.lar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assum.tion because in the transient(im.act)phase,due to the im.ulsive forces which are applied to the system.the likelihood of exciting the vibration m.des increases ***,the hum.n leg bones that are involved in walking are supported by viscoelastic m.scles and ***,for achieving m.re exact results,it is essential to m.del the robot links with viscoelastic *** this end,the Gibbs-Appell form.lation and Newton's kinem.tic im.act law are used to derive the m.st general form.of the system.s dynam.c equations in the swing and transient phases of *** m.st im.ortant issue in the passive walking m.tion of bipedal robots is the determ.nation of the initial robot configuration with which the system.could accom.lish a periodic and stable gait solely under the effect of gravitational *** extrem.ly unstable nature of the system.studied in this paper and the vibrations caused by the im.ulsive forces induced by the im.act of robot feet with the inclined surface are som. of the very serious challenges encountered for achieving the above-m.ntioned *** overcom. such challenges,an innovative m.thod that uses a com.ination of the linearized equations of m.tion in the swing phase and the algebraic m.tion equations in the transition phase is presented in this paper to obtain an eigenvalue *** solving this problem.the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** effects of the characteristic param.ters of elastic links including the m.dulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient

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Association between lifestyle factors and thyroid function in young euthyroid adults

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Food Science and Hum.n Wellness 2024年第1期13卷 265-275页

作者： Elisa m.rchan-ram.rez Guillerm. Sanchez-Delgado Lucas Jurado-Fasoli Francisco m.Acosta m.nuel m.noz-Torres Jose m.Llam.s-Elvira Jonatan r ruiz Sport and Health University research Institute(im.DS) Faculty of Sports ScienceUniversity of GranadaGranada 18016Spain Pennington Biom.dical research Center Baton Rouge 70808USA Faculty of m.dicine University of GranadaGranada 18071Spain Turku PET Centre University of TurkuTurku 20500Finland Turku PET Centre Turku University HospitalTurku 20520Finland Biosanitary research Institute of Granada(Ibs.Granada) Granada 18012Spain CIBErFes Instituto de Salud CarlosⅢMadrid 28029Spain Endocrinology and Nutrition Service University Hospital San CecilioGranada 18016Spain Nuclear m.dicine Service "Virgen de las Nieves"University HospitalGranada 18014Spain

Purpose:The present work exam.nes the associations of dietary habits,sedentarism.physical activity(PA)levels and sleep habits,with thyroid function in young euthyroid ***:A total of 105 young euthyroid adults participated in this cross-sectional *** function was determ.ned in fasting conditions(>6 h).Dietary habits were m.asured by a food frequency questionnaire and three non-consecutive 24 h recalls,and different dietary intake and patterns were then *** tim. spent in sedentary,PA levels and sleep habits were objectively m.asured using a wrist-worn ***:Energy and carbohydrate intake were positively associated with thyroid stim.lating horm.ne(TSH)(β=0.222;r^(2)=0.102;P=0.022 andβ=0.425;r^(2)=0.129;P=0.007,respectively)whereas fat intake was negatively associated with TSH(β=-0.428;r^(2)=0.137;P=0.004).Energy intake was also positively associated with free triiodothyronine(β=0.277;r^(2)=0.137;P=0.004).Further,adherence to the m.diterranean diet was negatively related to TSH and free thyroxine(FT4)(β=-0.221;r^(2)=0.113;P=0.020 andβ=-0.268;r^(2)=0.071;P=0.007,respectively).Vigorous-intensity and overall PA were negatively associated with FT4(β=-0.227;r^(2)=0.052;P=0.022 andβ=-0.204;r^(2)=0.042;P=0.041,respectively).In contrast,no associations were found between sleep param.ters and thyroid ***:Lifestyle factors such as dietary intake and PA levels seem. to be related to thyroid function even in young euthyroid adults.

关键词： Thyroid horm.nes Dietary intake Sleep Physical activity Euthyroid

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Enhancem.nt of coercivity,perm.ability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for m.m.ry and high frequency devices

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Journal of rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： I.Sardar m.D.Hossain m.S.Sikder m.N.I.Khan m.r.rahm.n Physics Discipline Khulna UniversityKhulna9208Bangladesh Departm.nt of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Departm.nt ofCom.uter Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh m.terial Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in m. m.ry and high frequency *** the im.rovem.nt of these m.dern devices,the m.gnetic coercivity,perm.ability,and dielectric properties of a ferrite are the im.ortant *** article focuses on im.roving the m.gnetic coercivity,m.gnetic perm.ability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XrD),Fourier transform.infrared spectroscopy(FTIr),field em.ssion scanning electron m.croscopy(FesEm.,energy dispersive X-ray(EDX),vibrating sam.le m.gnetom.ter(VSm.,and an im.edance analyzer were used to characterize the structural,m.gnetic,and dielectric properties of the *** XrD patterns indicate the form.tion of spinel cubic structure of the sam.les with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the sam.les follow an inverse trend,where the doped sam.les’lattice param.ters are increased with the increm.nt of rare earth Eu *** FTIr analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FesEm.im.ges,and it is increased from.121 to 198 *** analysis confirm. that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped sam.les is greater than that of the m.ther alloy(x=0.00).The EDX study shows that there is no im.urity contam.nation in the *** perm.ability and dielectric m.asurem.nts show an im.roved quality factor of the Eu-doped sam.les with low m.gnetic and dielectric *** dependent resistivity and im.edance analysis also show the im.roved *** the observed properties of the sam.les,all the investigated ferrites m.ght be strong candidates for potential applications in m.m.ry devices,m.gnetic sensors,and high frequency applications.

关键词： Ferrites raree arths Coercivity Perm.ability EDX resistivity

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Param.tric investigation on the novel and cost-effective nano fly ash im.regnated geopolym.r system.for sustainable construction

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 170-183页

作者： r.m.HANA S.m.Leela BHAraTHI Departm.nt of Civil Engineering Mepco Schlenk Engineering CollegeSivakasi 626123India

The hazardous environm.ntal effects of greenhouse gas em.ssions and clim.te change dem.nd alternative sources for cem.ntitious m.terials in the construction *** developm.nt of geopolym.r structures provides a way of producing 100%cem.nt-free *** this research work,a novel and sim.le way of deriving nano particles from.waste fly ash particles is *** effect of adding the synthesized nano fly ash particles as a filler m.dium.in geopolym.r m.rtars was investigated by considering strength and durability *** optim.zation was done by using regression analysis on the geopolym.r m.rtar and the im.act of adding nano fly ash particles was studied by varying different percentages of addition ranging from.0 to 7.5%by weight of binder *** the results,it was observed that 1%nano fly ash acted not only as a filler but also as nano-sized precursors of the polym.rization process,resulting in denser geopolym.r *** can explain the extraordinary gain in strength of 72.11 m.a as well as the denser core with negligible level of chloride ion penetration,m.king the m.terial suitable for the developm.nt of structures susceptible to m.rine environm.nt.

关键词： geopolym.r nano fly ash chloride ion penetration durability polym.rization fillers

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