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Journal of Bionic Engineering 2017年第4期14卷 791-803页

作者： David Bach tom Masselter Thomas Speck Plant Biomechanics Group Freiburg Botanic Garden Faculty of Biology University of Freiburg Schginzlestr. 1 79104 Freiburg Germany Freiburg Materials Research Center (FMF) Stefan-Meier-StraBe 21 79104 Freiburg Germany Competence Networks Biomimetic and BIOKON e. V. Schainzlestr. 1 79104 Freiburg Germany

The present study evaluates the potential of a bio-inspired pulsation damper in a vane pump used in mobile hydraulic ap- plications. Pressure pulsations caused by such positive displacement pumps can lead to malfunctions and noise in a hydraulic system. A common measure to reduce pressure pulsations is the integration of pressure pulsation dampers downstream of the pump. This type of damping measure can also be found in biology as e.g. in the human blood circulatory system. Such working principles found in living organisms offer a high potential for a biomimetic transfer into technical applications. The newly developed bio-inspired damper consists of cellular rubbers with non-linear viscoelastic material properties. In order to evaluate the new damping method, pressure pulsations were measured at two different back pressures and at a wide engine speed range of the vane pump. For further assessment, different setups, varying the stiffness of the cellular rubber materials and the damper volume, were tested. Within the tested back pressures, the pressure pulsations could be reduced by up to 40%. The developed integrated pulsation damper offers a high potential to dampen pressure pulsations of positive displacement pumps used in mobile hydraulic applications ooeratin~ below 10 bar.

关键词： pressure pulsations pressure ripple vane pump bio-inspired pulsation damping cellular rubbers flexible foams

Correlation between MEG and BOLD fMRI signals induced by visual flicker stimuli

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仪器仪表学报 2007年第4期28卷 577-582页

作者： Chu Renxin Holroyd tom Duyn Jeff Department of Radiology Harvard Medical School Boston Massachusetts USA MEG Core Facility National Institute of Mental Health National Institutes of Health Bethesda Maryland USA Advanced MRI Section LFMI National Institute of Neurological Disorders and Stroke National Institutes of Health Bethesda Maryland USA

The goal of this work was to investigate how the MEG signal amplitude correlates with that of BOLD fMRI. To investigate the correlation between fMRI and macroscopic electrical activity, BOLD fMRI and MEG was performed on the same subjects (n=5). A visual flicker stimulus of varying temporal frequency was used to elicit neural responses in early visual areas. A strong similarity was observed in frequency tuning curves between both modalities. Although, averaged over subjects, the BOLD tuning curve was somewhat broader than MEG, both BOLD and MEG had maxima at a flicker frequency of 10 Hz. Also, we measured the first and second harmonic components as the stimuli frequency by MEG. In the low stimuli frequency (less than 6 Hz), the second harmonic has comparable amplitude with the first harmonic, which implies that neural frequency response is nonlinear and has more nonlinear components in low frequency than in high frequency.

关键词：视频 fMRI MEG 信号

Plants and Animals as Concept Generators for the Development of Biomimetic Cable Entry Systems

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Journal of Bionic Engineering 2008年第2期5卷 167-173页

作者： tom Masselter Uwe Scharf Thomas Speck Plant Biomechanics Group Botanic Garden of the University Freiburg Rittal GmbH & Co.KG Auf dem SttzelbergHerborn D-35745Germany

Many animals and plants have high potential to serve as concept generators for developing biomimetic materials and structures. We present some ideas based on structural and functional properties of plants and animals that led to the development of two types ofbiomimetic cable entry systems. Those systems have been realized on the level of functional demonstrators.

关键词： bionics biomimetics cable entry stents folding structures

Micromechanical modeling of polycrystalline high manganese austenitic steel subjected to abrasive contact

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Friction 2020年第3期8卷 626-642页

作者： Matti LINDROOS Anssi LA UKK ANEN tom ANDERSSON VTT Lifecycle Solutions Tampere 33720Finland

This study focuses on microstructural and micromechanical modeling of abrasive sliding contacts of wear-resistant Hadfield steel.3 D finite element representation of the microstructure was employed with a crystal plasticity model including dislocation slip,deformation twinning,and their *** results showed that deformation twinning interacting with dislocations had a key role in the surface hardening of the material,and it was also important for the early hardening process of the sub-surface grains beyond the heavily distorted surface *** effects of grain orientation and microstructural features were discussed and analyzed according to the micromechanical model to give a perspective to the anisotropy of the material and the feasibility of using micromechanics in virtual material design.

关键词： crystal plasticity micromechanical modeling of abrasion austenitic manganese steel deformation twinning

On Marx's View of Freedom

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学术界 2018年第12期 225-231页

作者： tom Rockmore Duguesne University Pittsburgh USA

This paper has briefly examined Marx's conception of freedom in modern industrial society. Even a rapid comparison indicates Marx says different things at different *** emphasis shifts from,say,an initial view of freedom based on a quasi-Hegelian view of radical equality and even love to freedom beyond the division of labor,then later a very different view of freedom based on a shorter working day,and so on.

关键词： Marx Marx's view of freedom

Rehabilitation of historic Shibam and Zabid,Yemen as an impulse for community and economy

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Built Heritage 2021年第3期5卷 110-120页

作者： tom Leiermann ICOMOS Germany BerlinGermany.2 UNESCO DohaDohaQatar

Conditions in Yemen involving armed confict and all kinds of structural challenges have also their impact on the fate of its built ***’s three World Heritage Sites have their particular signifcance,all of them representing a region with its own cultural background:Sanaa in the highlands,Zabid in the coastal Tihama,and Shibam in the remote desert valley of *** the Old City of Sanaa,the two smaller sites struggle with the limited resources of low-developed *** preserve a unique urban culture:Zabid with its many elements of elaborate artistry and a vernacular architecture highly adapted to tropical conditions,and Shibam as a dense structure of unique mud-built tower *** in a background of poverty,weak capacities of ofcial structures,and even war destruction risks can only succeed in connection with active engagement and commitment of the community,which however is heterogeneous and heritage preservation is not always their *** strategies must therefore link local livelihood interests to preservation *** quarter and housing rehabilitation in both cities in last years had wide backing,supported income and resulted in visible upgrading of the very heart of these cities—showing locals recovery of historic structures has its potentials—even in the extreme conditions of Yemen.

关键词： Yemen Earthen architecture Heritage conservation Zabid Shibam Vernacular architecture

Dyadic Green Function for an Electromagnetic Medium Inspired by General Relativity

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Chinese Physics Letters 2006年第4期23卷 832-833页

作者： Akhlesh Lakhtakia tom G. Mackay CATMAS Department of Engineering Science and Mechanics Pennsylvania State University University Park PA 16802-6812 USA School of Mathematics University of Edinburgh Edinburgh EH9 3JZ United Kingdom

The dyadic Green function for a homogeneous electromagnetic medium inspired by the spatiotemporally nonhomogeneous constitutive equations of gravitationally affected vacuum is derived.

关键词： FIELDS

Uncertainty quantification of stability and damage detection parameters of coupled hydrodynamic-ground motion in concrete gravity dams

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 303-323页

作者： Nazim Abdul NARIMAN tom LAHMER Pevman KARAMPOUR Institute of Structural Mechanics Faculty of Civil EngineeringBauh aus Universitat Weimar99423 WeimarGermany Department of Mechanical Engineering Faculty of EngineeringArak UniversityArak 38156-8-8849Iran

In this paper, models of the global system of the Koyna dam have been created using ABAQUS software considering the dam-reservoir-fbundation interaction. Non coupled models and the coupled models were compared regarding the horizontal displacement of the dam crest and the differential settlement of the dam base in clay foundation. Meta models were constructed and uncertainty quantification process was adopted by the support of Sobol's sensitivity in dices considering five un certain parameters by exploiting Box-Behnken experimental method. The non coupled models results determined overestimated predicted stability and damage detection in the dam. The rational effects of the reservoir height were very sensitive in the variation of the horizontal displacement of the dam crest with a small interaction effect with the beta viscous damping coefficient of the clay fbundation. The modulus of elasticity of the clay foundation was the decisive parameter regarding the variation of the differential settlement of the dam base. The XFEM approach has been used for damage detection in relation with both minimum and maximum values of each uncertain parameter. Finally the effects of clay and rock foundations were determined regarding the resistance against the propagation of cracks in the dam, where the rock fbundation was the best.

关键词： massed foundation hydrodynamic pressure Box-Behnken method meta model Sobol's sensitivity indices

Experimental Investigation of Effects of Reynolds Number and Incidence Angle on Secondary Flow within a Linear Blade Cascade

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Journal of Thermal Science 2021年第6期30卷 2122-2136页

作者： FLÍDR Erik JELÍNEK tomáš KLADRUBSKÝMilan Laboratory of High Speed Aerodynamics Czech Aerospace Research CenterBeranovych 130Prague 19905Czech Republic

The kinetic energy loss and the secondary loss downstream of a high turning nozzle cascade were *** of the incidence angle(i=-25°,0°and 25°)and Reynolds number(Re_(2,is)=0.8×10^(5),1.2×10^(5),2.5×10^(5) and 4.5×10^(5))were studied on two cascade configurations defined by different pitch to chord ratio(t/c=0.6 and 0.9),*** at the cascade inlet were performed by means of Preston tube,while at the cascade outlet by means of miniature pyramid five-hole pressure *** effect of studied parameters on the flow field at the cascade outlet was shown by the distribution of the kinetic energy loss,secondary loss,mix-out loss and streamwise vorticity.

关键词： linear blade cascade secondary loss pressure measurement

Energy balance model to assess the resistance of ballistic protection materials

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Defence Technology（防务技术） 2023年第12期30卷 141-153页

作者： Bogdan Stirbu Irene Ndindabahizi tom Vancaeyzeele Cyril Robbe Department of Weapon Systems and Ballistics Royal Military AcademyBrussels 1000Belgium

NATO standards"AEP-2920 Procedures for the Evaluation and Classification of Personal Armor"and NIJ Standard-0101.06,indicate the method to statistically assess the resistance of personal ballistic protection *** be validated and accepted through these procedures,a personal ballistic protection material should withstand an impact of a specific projectile with a probability of a partial penetration confidence level higher than 90%.The present study introduces an energy equilibrium method to assess the confidence level for the probability of partial penetration of ductile and brittle *** experiments performed in the Ballistics laboratory of the Royal Military Academy in Belgium,use a modified pendulum method that allowed the quantification of the energy balance before and after the ballistic *** results were then compared with the ones obtained using the method specified by the NATO standard and NIJ 0101.06,mentioned *** outcome of this comparison shows the tendency of the values obtained by the pendulum method to faithfully follow the values obtained according to NATO and NIJ *** presented method is not based on statistical estimations,but instead,an exact method,of computing the energy absorbed by the tested *** is an advantage for the cases when the material to be evaluated is expensive or it is in the development phase and mass production is not possible.

关键词： Energy NATO Ballistic Protection materials Statistics NIJ Bootstrapping