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DEM investigation of strength and critical state behaviours of granular materials under true triaxial loadings

Particuology 2024年第2期85卷 198-212页

作者： Minyi Zhu Guobin Gong Jun Xia Stephen wilkinson Department of Civil Engineering Xi'an Jiaotong-Liverpool UniversityChina Department of Civil Engineering and Industrial Design University of LiverpoolLiverpoolUK Faculty of Engineering and Information Sciences University of Wollongong in DubaiUnited Arab Emirates

This paper investigates the strength and critical state(CS)behaviours of granular materials via DEM simulations of true triaxial drained tests under three different loading modes including constant b(in-termediate stress ratio)tests with constantσ'1(major principal stress),constant p(mean pressure)and constantσ'3(minor principal stress)*** this end,a series of samples are generated with the same particle size distribution,and with the confining stresses ranging from 100 kPa to 900 *** CS is achieved for all *** the ma.r.scopic behaviours and the microscopic behaviours are examined and compared considering different loading modes,confining stresses and intermediate stress ratios(b).The critical state lines(CSLs)are found to be unique and independent of the loading modes,but dependent on the b *** CSLs with b=0 and b=1 form the two boundaries of CSLs respectively beyond which CSLs under all other b tests cannot go *** different strength criteria are examined and compared in terms of both peak and CS *** Mohr-Coulomb strength criterion is found to be only suitable for axisymmetric loading *** Lade-Duncan criterion is only suitable for describing peak strengths,which is dependent on the loading modes and confining *** Satake criterion and Matsuoka-Nakai criterion are the more appropriate strength criteria for describing CS failures,indicating that the CS values of both the Satake parameter and the Matsuoka-Nakai parameter describe an inherent property that characterizes the CS failure for a given type of *** CS mechanical coordination number is fitted by a curved line for a given b value,which is unique regardless of the loading *** peak and CS values of both major and minor principal fa.r.c tensors decrease with increasing b values,while they increase with increasing b values for the intermediate principal fa.r.c tensor.

关键词： Discrete element method Intermediate stress ratio Dilation Critical state Failure criterion

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早产儿严重视网膜病的基于英国人群研究:筛查、治疗和转归

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世界核心医学期刊文摘（儿科学分册） 2005年第10期1卷 24-25页

作者： Haines L. Fielder a.r. BakerH. wilkinson a.r. 郭战宏 Departmen t of Paedia.r.cs John Radcliffe Hospital University of Oxford Oxford OX3 9DU United Kingdom Prof.

Background: retinopathy of prematurity (rOP) is one of the few causes of child hood blindness in which severe vision impa.r.ent is largely preventable. Ophthal mic screening for rOP is required to identify disease that requires treatment wh ereby the development of potentially blinding disease can be minimised. Objectiv es: To make the first UK population based estimate of the incidence of babies wi th severe rOP (stage 3 or more); to document their clinical characteristics and management and to evaluate the appropriateness of current rOP screening guidelin es in the UK. Patients: Cases were recruited through a national surveillance pro gramme with 1 year ophthalmic follow up and data from clinician completed questi onna.r.s. results: Between 1 December 1997 and 31 March 1999, 233 preterm babies with st age 3 rOP were identified. Severity (location, extent, and presence of plus dise ase) was associated with degree of prematurity, most severe in the most prematur e babies. Fifty nine percent were treated. The UK screening protocol was followe d in two thirds of cases, but in the remainder itwas begun too late orwas too in frequent. Three quarters of the cases were followed up at 1 year, and 13%had a severe vision deficit as a.r.sult of rOP. Conclusions: Visual deficit as a.r.sul t of rOP in premature babies continues to be a severe disability in some of the survivors of neonatal intensive care. Further efforts are needed to organise tre atment regionally to improve outcome and standards of practice.

关键词：早产儿视网膜病视力损害监测计划适当性实践标准生存者临床医师

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英国早产儿重症视网膜病变筛查、治疗和疗效的人群研究

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世界核心医学期刊文摘（眼科学分册） 2005年第9期1卷 1-2页

作者： Haines L. Fielder a.r. Baker H. wilkinson a.r. 陈立军 Department of Paedia.r.cs John Radcliffe Hospital University of Oxford Oxford OX3 9DU United Kingdom Prof.

Background: retinopathy of prematurity (rOP) is one of the few causes of childhood blindness in which severe vision impa.r.ent is largely preventable. Ophthalmic screening for rOPis required to identify disease that requires treatment whereby the development of potentially blinding disease can be minimised. Objectives: To make the first UK population based estimate of the incidence of babies with severe rOP(stage 3 or more); to document their clinical characteristics and management and to evaluate the appropriateness of current rOPscreening guidelines in the UK. Patients: Cases were recruited through a national surveillance programme with 1 year ophthalmic follow up and data from clinician completed questionna.r.s. results: Between 1 December 1997 and 31 March 1999, 233 preterm babies with stage 3 rOP were identified. Severity (location, extent, and presence of plus disease) was associated with degree of prematurity, most severe in the most premature babies. Fifty nine percent were treated. The UK screening protocol was followed in two thirds of cases, but in the remainder it was begun too late or was too infrequent. Three quarters of the cases were followed up at 1 year, and 13%had a severe vision deficit as a.r.sult of rOP. Conclusions: Visual deficit as a.r.sult of rOPin premature babies continues to be a severe disability in some of the survivors of neonatal intensive care. Further efforts are needed to organise treatment regionally to improve outcome and standards of practice.

关键词：视网膜病变筛查标准视力损害新生儿重症监护诊治标准卫生监测临床医生伴发病筛选标准问卷调查

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对缺氧缺血后足月儿行畸变产物耳声发射检查

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世界核心医学期刊文摘（儿科学分册） 2005年第7期1卷 24-25页

作者： Ze D.J. Zhang Z. wilkinson a.r. 高蕊 Department of Paedia.r.cs Children's Hospital Fudan University Shanghai China

Distortion product otoacoustic emissions (DPOAEs) were recorded in 46 term infants who suffered perinatal hypoxia-ischaemia to identify which frequencies in the cochlear audiogram are susceptible to perinatal *** days 3-5 after birth, the pass rates a.r.ss the frequencies of the f2 primary tone between 1 and 10 kHz, particularly 1-5 kHz, were all lower than those in normal term controls (X2 = 7.27-32.30, all P rs, 15 (16.3%) failed the DPOAE test, which was significantly higher than in the controls (4.3%, X2 = 5.81, P rs with a type A tympanogram were *** pass rates at most frequencies, mainly 1 and 2 kHz, were slightly further *** ears (16.2%) failed the DPOAE *** results suggest that the neonatal cochlea, mainly at the frequencies 1-5 kHz, is impa.r.d shortly after perinatal hypoxia-ischaemia and the impa.r.ent remains at 1 ***: Perinatal hypoxia-ischaemia impa.r. the neonatal cochlea mainly at the frequencies 1-5 kHz and the impa.r.ent detected on days 3-5 after birth is unlikely to improve in the later neonatal *** findings may have implications for the management of hearing impa.r.ent in infants after perinatal hypoxia-ischaemia.

关键词：围生期缺氧听力障碍出生后

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Analysis and Optimization of Operational and Pollutant Attributes of Diesel Engine with CNT-Infused Orange Peel Biodiesel-Diesel Blend Fuel

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Journal of Thermal Science 2024年第2期33卷 761-778页

作者： ranjeet rAI r.r.SAHOO Mechanical Engineering Department GLA UniversityMathura281406India Mechanical Engineering Department IIT(BHU)Varanasi221005India

The current study is performed to find sustainable solutions for the future of transportation and environmental *** conventional methods and experimental design table(L16 Orthogonal a.r.y)techniques have been employed to examine and optimize a diesel-powered engine's operational and pollutant *** L16 Orthogonal a.r.y is obtained through Taguchi's experimental design approach using Minitab 16 *** experimental design incorporated three control variables,namely engine speed,fuel type,and engine load,each with four *** operational parameters,namely brake thermal efficiency(BTE)and brake specific fuel consumption(BSFC),as well as the emission characteristics,including hydrocarbon(HC),carbon monoxide(CO),nitrogen oxide(NO),and smoke emissions,were acquired using the L16 orthogonal a.r.y(OA) and subsequently *** utilization of methodologies such as signal-to-noise(S/N) ratio and grey analysis was employed to determine the optimal operational state of the engine to achieve maximum performance while minimizing *** engine's ideal state of operation,in terms of BTE and BSFC,was determined to be at 75% engine load,1000 r/min engine speed,and using 10^(-4)(in vol) carbon nanotube incorporated 20% orange peel biodiesel(OPB20CNT100) blended fuel(A3-B1-C4).The study indicated that engine load significantly influenced BTE and BSFC,with 84.05% and 87.79% contribution factors,*** 25% engine load,1000 r/min,and OPB20CNT100 fuel(A1-B1-C4) CO,smoke,NO,and HC emissions were the *** load affects emissions the *** BSFC increased 3.10% and NO emissions 1.77%.BTE,CO,smoke,and HC emissions decreased by 1.9%,12.29%,47.05%,and 47.22%,respectively,at optimal operating conditions concerning diesel *** study shows that Taguchi-Grey's experimental design optimizes diesel engine operational and pollutant *** outcomes revealed that orange peel biodiesel infused with CNT can replace diesel fuel in a

关键词： Taguchi-Grey method OPB20CNT100 transesterification S/N ratio GrG HC CO and NO

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Kinematic analysis of flexible bipedal robotic 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 Department of Mechanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of *** most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational *** extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned *** overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion 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 parameters of elastic links including the modulus 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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Holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： H r Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

recently, reconsidering the rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. Hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~H^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

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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 primarily focused on the pile foundation behavior in two or three-layered soil ***,in natural occurrence,it may occur in alternative layers of liquefiable and non-liquefiable ***,the experimental and/or numerical studies on the layered effect on pile foundations have not been widely addressed in the *** of the design codes a.r.ss the world do not explicitly mention 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 kinematic bending moment 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 might be a nonconservative design approach.

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

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Conservation laws,Lie symmetries,self adjointness,and soliton solutions for the Selkov–Schnakenberg system

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Communications in Theoretical Physics 2024年第2期76卷 29-44页

作者： Kashif Ali Aly r Seadawy Syed T r rizvi Noor Aziz Department of Mathematics COMSATS University IslamabadLahore CampusPakistan Mathematics Department Faculty of ScienceTaibah UniversityAl-Madinah Al-Munawarah41411Saudi Arabia

In this article,we explore the famous Selkov–Schnakenberg(SS)system of coupled nonlinear partial differential equations(PDEs)for Lie symmetry analysis,self-adjointness,and conservation ***,miscellaneous soliton solutions like dark,bright,periodic,rational,Jacobian elliptic function,Weierstrass elliptic function,and hyperbolic solutions of the SS system will be achieved by a well-known technique called sub-ordinary differential *** these results are displayed graphically by 3D,2D,and contour plots.

关键词： Selkov-Schnakenberg system Lie symmetry analysis conservation laws adjointness integrability

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FEA-based Geometrical Modification of Switched reluctance Motor for radial Force reduction

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Chinese Journal of Electrical Engineering 2024年第1期10卷 124-135页

作者： rani S Jaya.r.gash r School of Electrical Engineering Vellore Institute of TechnologyChennai 600127India

Switched reluctance motors(SrMs)are becoming increasingly popular in the automotive sector owing to their robust ***,SrMs are preferred particularly for EV applications owing to their fault tolerance,magnet-free structure,and high power/torque *** main concerns of SrM compared to other machines include torque ripple and *** primary cause of vibration is the radial force created by the SrM.A geometry-based modification of the SrM to reduce the radial force without significantly changing the average torque produced is *** primary goal is to design a 4-phase,8/6 SrM with a lower radial *** possible geometrical alterations are proposed:one with square windows and the other with circular holes on the rotor *** windows are sized and positioned to avoid flux *** criteria are developed for the optimal window size and *** element analysis(FEA)modelling of the SrM is used to validate its *** FEa.r.sults are compared with the performance parameters obtained using the analytical *** the multiphysics design tool ANSYS to obtain the natural frequencies and associated deformations through modal *** to the conventional geometry,the radial force is significantly reduced by providing windows.

关键词： 8/6 SrM radial force modal analysis FEA analysis natural frequencies SrM with windows

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