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Heat Transfer and Fluid Flow over a Single Disk in a Fluid Rotating as a Rigid Body

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Journal of Thermal Science 2004年第3期13卷 279-282页

作者： Igor V. SHEVCHUK matthias H. BUSCHMANN Institute of Engineering Thermophysics Ukrainian National Academy of Sciences 2a Zhelyabov St. Kiev 03057 UkraineInstitute of Fluid Mechanics Dresden University of Technology 01062 Dresden Germany

Laminar heat transfer problem is analyzed for a disk rotating with the angular speed ωin a co-rotating fluid (with the angular speed Ω). The fluid is swirled in accordance with a forced-vortex law, it rotates as a solid body at β= Ω/ω= const. Radial variation of the disk’s surface temperature follows a power law. An exact numerical solution of the problem is obtained basing on the self-similar profiles of the local temperature of fluid, its static pressure and velocity components. Numerical computations were done at the Prandtl numbers Pr = 1(?)0.71. It is shown that with increasing βboth radial and tangential components of shear stresses decrease, and to zero value at β= 1. Nusselt number is practically constant at β= 0(?) 0.3 (and even has a point of a maximum in this region); Nu decrease noticeably for larger βvalues.

关键词： rotating disk heat transfer fluid flow Nusselt number swirl.

Robust reconstruction of curved line structures in noisy point clouds

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Visual Informatics 2021年第3期5卷 1-14页

作者： Marcel Ritter Daniel Schiffner matthias Harders Interactive Graphics and Simulation Group Department of Computer ScienceUniversity of InnsbruckAustria Airborne Hydromapping GmbH InnsbruckAustria DIPF|Leibniz Institute for Research and Information Education FrankfurtGermany

Point-based geometry representations have become widely used in numerous contexts,ranging from particle-based simulations,over stereo image matching,to depth sensing via light detection and *** application focus is on the reconstruction of curved line structures in noisy 3D point cloud *** algorithms operating on such point clouds often rely on the notion of a local *** the latter,our approach employs multi-scale neighborhoods,for which weighted covariance measures of local points are *** line structures are reconstructed via vector field tracing,using a bidirectional piecewise streamline *** also introduce an automatic selection of optimal starting points via multi-scale geometric *** pipeline development and choice of parameters was driven by an extensive,automated initial analysis process on over a million prototype test *** behavior of our approach is controlled by several parameters—the majority being set automatically,leaving only three to be controlled by a *** an extensive,automated final evaluation,we cover over one hundred thousand parameter sets,including 3D test geometries with varying curvature,sharp corners,intersections,data holes,and systematically applied varying types of ***,we analyzed different choices for the point of reference in the co-variance computation;using a weighted mean performed best in most *** addition,we compared our method to current,publicly available line reconstruction *** to thirty times faster execution times were achieved in some cases,at comparable error ***,we also demonstrate an exemplary application on four real-world 3D light detection and ranging datasets,extracting power line cables.

关键词： Computational geometry Noisy point clouds Line reconstruction Automatic Adaptive control

Evaluation of Transmission Losses of Various Battery Electric Vehicles

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Automotive Innovation 2022年第4期5卷 388-399页

作者： Johannes Hengst matthias Werra Ferit KüÇükay Institute of Automotive Engineering TU BraunschweigBraunschweigGermany

Transmission losses in battery electric vehicles have compared to internal combustion engine powertrains a larger share in the total energy consumption and play therefore a major ***,the power flows not only during propulsion through the transmissions,but also during recuperation,whereby efficiency improvements have a double *** investigation of transmission losses of electric vehicles thus plays a major *** this paper,three simulation models of the Institute of Automotive Engineering(the lossmap-based simulation model,the modular simulation model,and the 3D simulation model)are *** lossmap-based simulation model calculates transmission losses for electric and hybrid transmissions,where three spur gear transmission concepts for battery electric vehicles are *** transmission concepts include a single-speed transmission as a reference and two two-speed ***,the transmission lossmaps are integrated into the modular simulation model(backward simulation)and in the 3D simulation model(forward simulation),which improves the simulation *** modular simulation model calculates the optimal operation of the transmission concepts and the 3D simulation model represents the more realistic behavior of the transmission *** different transmission concepts are investigated in Worldwide Harmonized Light Vehicle Test Cycle and evaluated in terms of transmission losses as well as the total energy *** map-based simulation model allows the transmission losses to be broken down into the individual component losses,thus allowing transmission concepts to be examined and evaluated in terms of their efficiency in the early development stage to develop optimum powertrains for electric axle *** considering transmission losses in detail with a high degree of accuracy,less efficient concepts can be eliminated at an early development *** a result,only relevant concepts are built as prototypes,which reduce

关键词： Battery electric vehicle(BEV) Transmission losses Efficiency analysis WLTC Backward simulation Forward simulation Energy consumption

GPS tracking of non-breeding ravens reveals the importance of anthropogenic food sources during their dispersal in the Eastern Alps

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Current Zoology 2016年第4期62卷 337-344页

作者： matthias-Claudio LORETTO Richard SCHUSTER Thomas BUGNYAR Department of Cognitive Biology University of Vienna Althanstrasse 14 A-1090 vienna Konrad Lorenz Forschungsstelle Core Facility for Behaviour and Cognition University of Vienna Fischerau 11 A-4645 GrLinau im Almtal Austria CDepartment of Forest and Conservation Sciences University of British Columbia Vancouver B.C. Canada V6T1Z4

In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens＇ behavior during dispersal in the Eastern Alps. We deployed Global Positioning System （GPS） loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify： 1） the dimension of the birds＇ space use （home range size with seasonal effects and daily/long-term travel distances）, 2） how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3） their destination of movements. We recorded movements of up to 40km per hour, more than 160km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and com- bines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these ＂feeding hot spots＂ and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.

关键词： common raven Corvus corax non-breeder space use dispersal kernel density.

Representations of molecules and materials for interpolation of quantum-mechanical simulations via machine learning

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npj Computational Materials 2022年第1期8卷 378-391页

作者： Marcel F.Langer Alex Goeßmann matthias Rupp NOMAD Laboratory Fritz Haber Institute of the Max Planck SocietyBerlinGermany Machine Learning Group Technische Universität BerlinBerlinGermany Institute of Mathematics Technische Universität BerlinBerlinGermany Citrine Informatics Redwood CityCAUSA Department of Computer and Information Science University of KonstanzKonstanzGermany

Computational study of molecules and materials from first principles is a cornerstone of physics,chemistry,and materials science,but limited by the cost of accurate and precise *** settings involving many simulations,machine learning can reduce these costs,often by orders of magnitude,by interpolating between reference *** requires representations that describe any molecule or material and support *** comprehensively review and discuss current representations and relations between *** selected state-of-the-art representations,we compare energy predictions for organic molecules,binary alloys,and Al–Ga–In sesquioxides in numerical experiments controlled for data distribution,regression method,and hyper-parameter optimization.

关键词： alloys corners precise

Development of a hybrid particle-mesh method for simulating free-surface flows

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Journal of Hydrodynamics 2017年第3期29卷 413-422页

作者： Jakob Maljaars Robert Jan Labeur matthias Moller Wim Uijttewaal Environmental Fluid Mechanics Section Faculty of Civil Engineering and GeosciencesDelft University of TechnologyDelftThe Netherlands Department of Applied Mathematics Delft University of TechnologyDelftThe Netherlands

In this work the feasibility of a numerical wave tank using a hybrid particle-mesh method is *** on the fluid implicit particle method（FLIP）a formulation for the hybrid method is presented for incompressible multiphase flows involving large density jumps and wave generating *** performance of the method is assessed for a standing wave and for the generation and propagation of a solitary wave over a flat and a sloping bed.A comparison is made with results obtained with a well-established SPH *** tests demonstrate that the method is a promising and attractive tool for simulating the nearshore propagation of waves.

关键词： Lagrangian-Eulerian particle-mesh free-surface flows numerical wave flume incompressible Navier-Stokes

Introduction:innovative heritage-based post-crisis urban recovery strategies

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Built Heritage 2023年第2期7卷 1-2页

作者： Christer Gustafsson matthias Ripp Department of Art History Uppsala University(SE)UppsalaSweden Department for cultural heritage RegensburgGermany

Resilience is a concept that has become more and more common during the last *** used in physics and psychology,just recently it has been transferred to the feld of urban planning,urban development and cultural *** purpose of this Special Issue of the international journal Built Heritage is to examine,and discuss,how the concept of resilience can be related to cultural *** understand resilience here in the sense of the SHELTER Resilience defnition which defnes diferent phases before,during and after a disaster or crisis.

关键词： journal disaster heritage

Exploring the modulatory role of bovine lactoferrin on the microbiome and the immune response in healthy and Shiga toxin-producing E. coli challenged weaned piglets.

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Predictive value of spleen stiffness in hepatocellular carcinoma

畜牧与生物技术杂志(英文版) 2024年第3期 1278页

作者： matthias Dierick Ruben Ongena Daisy Vanrompay Bert Devriendt Eric Cox

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Hepatobiliary Surgery and Nutrition 2020年第1期9卷 101-102页

作者： matthias Buechter Alisan Kahraman Department of Gastroenterology and Hepatology University Clinic of EssenUniversity of Duisburg-EssenEssenGermany St.Nikolaus-Stiftshospital AndernachGermany

In their Letter to the Editor, Wei et al. address on the role of spleen stiffness measurement (SSM) for predicting the late recurrence (>24 months post-surgery) of hepatocellular carcinoma (HCC) after resection (1). They comment on a recently published manuscript by Marasco and colleagues, who could show that spleen stiffness measured by transient elastography was the only predictor of late HCC recurrence after surgery (2).

关键词： spleen hepatocellular al.