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Mechanism of cross-level settlements and void accumulation of wide and conventional sleepers in railway ballast

Railway Engineering Science 2024年第3期32卷 361-383页

作者： Olga Nabochenko Mykola Sysyn Norman Krumnow Szabolcs fischer Institute of Railway Systems and Public Transport Technical University of DresdenDresdenGermany Rhomberg Sersa Deutschland GmbH BerlinGermany Central Campus Győr Széchenyi István UniversityGyorHungary

The cross-level and twist irregularities are the most dangerous irregularity types that could cause wheel unloading with the risk of derailments and additional maintenance ***,the mechanism of the irregularities initiation and development is *** motivation of the present study was the previous experimental studies on the application of wide sleepers in the ballasted *** long-term track geometry measurements with wide sleepers show an enormous reduction of the vertical longitudinal irregularities compared to the conventional ***,wide sleepers had higher twist and cross-section level *** present paper aims to explain the phenomenon by discrete element method(DEM)modeling the development process of sleeper inhomogeneous support at cross-level depending on the sleeper *** DEM simulations show that the maximal settlement intensity is up to 3.5 times lower for a wide sleeper in comparison with the conventional ***,the cross-level differential settlements are almost the same for both *** particle loading distribution after all loading cycles is concentrated on the smaller area,up to the half sleeper length,with fully unloaded zones under sleeper *** flow limitation under the central part of the sleeper could improve the resilience of wide sleepers to the development of cross-level *** mechanism of initiation of the cross-level irregularity is proposed,which assumes the loss of sleeper support under sleeper *** further growth of inhomogeneous settlements along the sleeper is assumed as a result of the interaction of two processes:ballast flow due to dynamic impact during void closing and on the other side high pressure due to the concentration of the pressure under the middle part of the *** DEM simulation results support the assumption of the mechanism and agree with the experimental studies.

关键词： Wide sleeper Ballasted track Sleeper support inhomogeneity Sleeper foot form Discrete element modeling Void accumulation

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Improving the dynamic stability of a workpiece dominated turning process using an adaptronic tool holder

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Theoretical & Applied Mechanics Letters 2013年第1期3卷 63-70页

作者： Achim fischer Peter Eberhard Institute of Engineering and Computational Mechanics University of Stuttgart

In this contribution, inside turning of a thin-walled cylinder is investigated in simulation. Self-excited vibrations can arise due to repeated cutting of the same surface, that lead to instability.A flexible multibody system model of the system is the basis for a subsequent analysis of the stability of the process. Stability analysis is done using an approximation as a time-discrete system via the semi-discretization method. An adaptronic turning chisel comprising a piezo actuator and sensors is then used in combination with different control concepts to improve the stability of the process. The effectiveness of the different strategies is compared based on the influence on the stability charts. A classic H∞ controller based on a model of the coupled system of workpiece and tool can only yield some improvements, when an additional measurement of the workpiece displacement is added. Incorporating knowledge on the cutting process coupling workpiece and tool using a gain scheduled H∞ controller allows further improvements. However, robustness with respect to model uncertainties, notably concerning the force law, remains an issue. C 2013 The Chinese Society of Theoretical and Applie-d Mechanics. [doi：10.1063/2.1301308]

关键词： multibody dynamics vibrations stability feedback control

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SUSTAINABILITY RATING SYSTEMS

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Journal of Green Building 2012年第2期7卷 177-203页

作者： Roshan Mehdizadeh Martin fischer Stanford University Civil and Environmental Engineering473 Via OrtegaStanfordCA94305

There are five different publications that establish guidelines for sustainable building development that are examined in this report:(1)Leadership in Energy and Environmental Design(“LEED”);(2)CalGreen;(3)the International Green Construction Code(“IGCC”);(4)ASHRAE Standard 189.1(“Standard 189.1”);and(5)The San Francisco’s Green Building Ordinance(“SFGBO”).Having multiple publications can cause confusion among building developers,architects,engineers,building consultants,or various jurisdictions on what publication to follow,use,or reference in building development *** article will provide various parties involved in building development a thorough understanding of each publication and the similarities or differences between them,which will ultimately assist in identifying areas for all publications to ***,this article demonstrates that the Material and Energy sections for all the publications must advance beyond the current ***,the comparison validates that CalGreen’s Tier 2 is similar to LEED’s local ordinances,like the *** may mean two things:(1)LEED will need to advance its gold or platinum certification requirements,or potentially become less relevant;or(2)local ordinances should reference or adopt CalGreen Tier 2 so that there is common language between local and state *** article identifies that LEED has the most stringent guidelines under the Building Site section out of all the ***,the IGCC and Standard 189.1 have provisions under the Water Use section,that goes beyond other ***,similar language between LEED and Standard 189.1 was found,which was unsurprising as both publications are authored by the USGBC.

关键词： sustainable building development local ordinances jurisdictions local and state regulations voluntary&involuntary green building rating systems LEED CalGreen IGCC ASHRAE 189.1 and SFGBO

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Endoscopic debridement for non-insertional Achilles tendinopathy with and without platelet-rich plasma

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Journal of Sport and Health Science 2023年第2期12卷 275-280页

作者： Hajo Thermann Ralph fischer Nikolaos Gougoulias Lucio Cipollaro Nicola Maffulli HKF-International Center for Hip Foot and Knee SurgeryBismarckstrae 9-1569115 HeidelbergGermany Footsurgery Clinic 54631 ThessalonikiGreece Department of Musculoskeletal Disorders Faculty of Medicine and SurgeryUniversity of SalernoSalerno 89100Italy Department of Medicine Surgery and DentistryUniversity of SalernoVia S.Allende84081 Baronissi(SA)Italy Centre for Sports and Exercise Medicine Barts and The London School of Medicine and DentistryMile End Hospital275 Bancroft RoadLondon E14DGQueen Mary University of LondonLondonUK School of Pharmacy and Bioengineering Keele University Faculty of MedicineThornburrow DriveStoke on TrentST47QBUK

Background:When non-operative management fails to improve symptoms in patients with non-insertional Achilles tendinopathy,surgery may be *** open and endoscopic techniques have been proposed,and platelet-rich plasma(PRP)injections have been proposed as an adjunct to aid tendon ***:Thirty-six patients with mid-portion Achilles tendinopathy were randomized to undergo endoscopic debridement alone(n=19)or in combination with intraoperative PRP application(n=17).Clinical outcome measures included the Visual Analogue Scale for pain,function,and satisfaction and the Victorian Institute of Sports Assessment-Achilles(VISA-A)*** were followed-up at 6 weeks,3months,6 months,and 12 months after *** MRI examination at 3 and 12 months was used to assess signal alterations within the ***:Both groups showed significant clinical improvement(p<0.05)after surgery,with no difference between the 2 *** diameter increased at 3 months and decreased at 12 *** tendinopathy area increased at 3 months and decreased at 12 months below baseline level in both *** was no significant difference between the groups regarding the MRI *** thickening and MRIdetected signal alteration persisted after surgery,with no association between imaging and clinical *** minor complications were reported:2 in the PRP group and 3 in the control ***:Endoscopic debridement of the Achilles tendon improved clinical outcomes in patients with mid-portion *** addition of PRP did not improve outcomes compared to debridement *** parameters showed no association with clinical outcomes.

关键词： Achilles tendon Endoscopic Non-insertional PRP Tendinopathy

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Simulating the evolution of a clonal trait in plants with sexual and vegetative reproduction

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Journal of Plant Ecology 2008年第3期1卷 161-171页

作者： Markus fischer Eckart Winkler Bernhard Schmid Institute of Plant Sciences University of BernAltenbergrain 21CH-3013 BernSwitzerland Institute for Biochemistry and Biology University of PotsdamMaulbeerallee 1D-14469 PotsdamGermany Department of Ecological Modelling Helmholtz Centre for Environmental Research UFZPO Box 500135D-04301 LeipzigGermany Institute of Environmental Sciences University of ZurichWinterthurerstrasse 190CH-8057 ZurichSwitzerland

Aims Phenotypic optimality models neglect ***,especially when heterozygous genotypes are fittest,evolving allele,genotype and phenotype frequencies may not correspond to predicted *** was not previously addressed for organisms with complex life *** Therefore,we modelled the evolution of a fitness-relevant trait of clonal plants,stolon internode *** explored the likely case of an asymmetric unimodal fitness profile with three model *** constant selection models(CSMs),which are gametic,but not spatially explicit,evolving allele frequencies in the one-locus and fiveloci cases did not correspond to optimum stolon internode length predicted by the spatially explicit,but not gametic,phenotypic *** deviation was due to the asymmetry of the fitness ***,spatially explicit individual-based(SEIB)modeling allowed us relaxing the CSM assumptions of constant selection with exclusively sexual *** findings For entirely vegetative or sexual reproduction,predictions of the gametic SEIB model were close to the ones of spatially explicit nongametic phenotypic models,but for mixed modes of reproduction they approximated those of gametic,not spatially explicit ***,in contrast to gametic SEIB models,phenotypic models and,especially for few loci,also CSMs can be very *** conclude that the evolution of traits governed by few quantitative trait loci appears hardly predictable by simple models,that genetic algorithms aiming at technical optimization may actually miss the optimum and that selection may lead to loci with smaller effects in derived compared with ancestral lines.

关键词： clonal plants ecological and evolutionary modelling genetic variation life-history evolution optimal life histories simulation model

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Experimental proof of Joule heating-induced switched-back regions in OLEDs

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Light(Science & Applications) 2020年第1期9卷 1951-1960页

作者： Anton Kirch Axel fischer Matthias Liero Jurgen Fuhrmann Annegret Glitzky Sebastian Reineke Dresden Integrated Center for Applied Physics and Photonic Materials(IAPP)and Institute of Applied Physics Technische Universitat DresdenNothnitzer StraBe 6101187 DresdenGermany Weierstrass Institute Berlin MohrenstraBe 3910117 BerlinGermany

Organic light-emitting diodes(OLEDs)have become a major pixel technology in the display sector,with products spanning the entire range of current panel *** ability to freely scale the active area to large and random surfaces paired with flexible substrates provides additional application scenarios for OLEDs in the general lighting,automotive,and signage *** applications require higher brightness and,thus,current density operation compared to the specifications needed for general *** extended transparent electrodes pose a significant ohmic resistance,OLEDs suffering from Joule self-heating exhibit spatial inhomogeneities in electrical potential,current density,and hence *** this article,we provide experimental proof of the theoretical prediction that OLEDs will display regions of decreasing luminance with increasing driving *** a two-dimensional OLED model,we can conclude that these regions are switched back locally in voltage as well as current due to insufficient lateral thermal ***,we demonstrate this effect in lab-scale devices and derive that it becomes more severe with increasing pixel size,which implies its significance for large-area,high-brightness use cases of ***,these non-linear switching effects cannot be ignored with respect to the long-term operation and stability of OLEDs;in particular,they might be important for the understanding of sudden-death scenarios.

关键词： OLEDs switched proof

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Heritability of early growth traits and their plasticity in 14 woody species of Chinese subtropical forest

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Journal of Plant Ecology 2017年第1期10卷 222-231页

作者： Xueqin Zeng Walter Durka Erik Welk Markus fischer UFZ-Helmholtz Centre for Environmental Research Department of Community Ecology(BZF)Theodor-Lieser-Str.4D-06120 HalleGermany Institute of Plant Sciences University of BernAltenbergrain 21CH-3013 BernSwitzerland Kadoorie Farm and Botanic Garden Lam Kam RoadTai PoNew TerritoriesHong Kong Institute of Biology Martin Luther University Halle-WittenbergAm Kirchtor 01D-06108 HalleGermany

Aims Genetic variation in plant traits represents the raw material for future adaptive *** extent can be estimated as heritability based on the performance of experimental plants of known relatedness,such as maternal half-sib seed *** there is considerable heritability information for herbaceous plants and commercially important trees,little is known for woody species of natural subtropical ***,it is open whether heritability is higher for species with r-or K-strategies,for more common species with larger distribution ranges than for rarer ones,or for populations closer to the centres of distributional *** For 14 woody species in Chinese subtropical forest,we collected 13-38 maternal seed families,assessed seed size,grew replicates of each seed family in one more and one less benign nursery environment and measured stem diameter and plant height after 7 *** findings For the different species,plants grew 1.8-8.1 times taller in the more benign *** all 14 species,variation between seed families(and thus heritability)was significant(with very few exceptions at the P<0.001 level)for seed size and for stem diameter and plant height in both ***,significant seed family by nursery interactions for stem diameter and plant height for all species(P<0.001)indicated significant heritability for plasticity in these *** regression analysis suggests that heritabilities were higher for species with higher age at reproduction and higher wood density(traits indicating a K strategy)but also for species with higher specific leaf area(a trait rather indicating an r strategy).Furthermore,heritabilities were higher for species with larger range sizes,while there was no significant relationship between heritabilities and the distance of the study area to the range margins of our study *** conclusion,the detected large heritability estimates suggest considerable potential for the evolution

关键词： heritability plant performance phenotypic plasticity subtropical forest

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Roughness Measurements with Polychromatic Speckles on Tilted Surfaces

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Nanomanufacturing and Metrology 2021年第4期4卷 237-246页

作者： Johannes Stempin Andreas Tausendfreund Dirk Stobener Andreas fischer Bremen Institute for Metrology Automation and Quality ScienceUniversity of BremenLinzer Str.1328359 BremenGermany

Surface light scattering enables contactless and fast measurements of surface roughness.A surface inclination alters the direction of the scattering beam and thus the measured surface roughness is calculated from the detected intensity ***,an accurate sensor-surface alignment is *** order to achieve tilt-independent roughness measurements,a model-based evaluation approach for polychromatic speckle patterns is *** evaluating the shape of the superposed speckles,which occur for polychromatic illumination,with regard to the distance to the scattering centre,surfaces with an Sa roughness value in the range of 0.8-3.2μm are *** investigations demonstrate that the influence of a surface tilt up to±1.25°on the roughness measurement is reduced by 90%.As a result,the robustness of the polychromatic speckle roughness measurement is improved,which allows to speed up the adjustment of the measurement system or the surface sample,respectively.

关键词： Surface roughness Polychromatic light scattering Surface tilting In-process measurement

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CXCR4 signaling in central nervous system regeneration: friend or foe?

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Neural Regeneration Research 2022年第7期17卷 1481-1483页

作者： Daniel Terheyden-Keighley Alexander M.Hilla Dietmar fischer Department of Cell Physiology Ruhr University of BochumUniversitätsstraβe 15044780 BochumGermany

The knockout of the chemokine C-X-C motif chemokine receptor 4(CXCR4)in growthstimulated retinal ganglion cells(RGCs)has a multiplicative effect on optic nerve regeneration.C-X-C motif chemokine ligand 12(CXCL12),the ... 详细信息

关键词： CXCL12 CXCR4 system

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LIVESTOCK PRODUCTION PLANNING UNDER ENVIRONMENTAL RISKS AND UNCERTAINTIES

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Journal of Systems Science and Systems Engineering 2006年第4期15卷 399-418页

作者： Günther fischer Tatiana ERMOLIEVA Yuri ERMOLIEV Harrij van VELTHUIZEN International Institute for Applied Systems Analysis Schlossplatz 1 A-2361 Laxenburg Austria

In this paper we demonstrate the need for risk-adjusted approaches to planning expansion of livestock production. In particular, we illustrate that under exposure to risk, a portfolio of producers is needed where more efficient producers co-exist and cooperate with less efficient ones given that the latter are associated with lower, uncorre, lated or even negatively correlated contingencies. This raises important issues of cooperation and risk sharing among diverse producers. For large-scale practical allocation problems when information on the contingencies may be disperse, not analytically tractable, or be available on aggregate levels, we propose a downscaling procedure based on behavioral principles utilizing spatial risk preference structure, It allows for estimation of production allocation at required resolutions accounting for location specific risks and suitability constraints. The approach provides a tool for harmonization of data from various spatial levels. We applied the method in a case study of livestock production allocation in China to 2030.

关键词： Spatial production allocation sequential downscaling cross-entropy maximum likelihood risks and uncertainties.

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