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See detailX oder U? Herders ‚Interkulturalität‘
Dembeck, Till UL

in Heimböckel, Dieter; Honnef-Becker, Irmgard; Mein, Georg (Eds.) Zwischen Provokation und Usurpation. Interkulturalität als (un)vollendetes Projekt der Literatur- und Sprachwissenschaften (2010)

Detailed reference viewed: 40 (3 UL)
See detailX wie Krux
Heimböckel, Dieter UL

Article for general public (2013)

Detailed reference viewed: 37 (1 UL)
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See detailXDEM - FEM Coupling Simulations of the Interactions between a Tire Tread and Granular Terrain
Michael, Mark UL; Vogel, Frank; Peters, Bernhard UL

E-print/Working paper (2014)

This study proposes an efficient combination of the Discrete Element Method (DEM) and the Finite Element Method (FEM) to study the tractive performance of a rubber tire in interaction with granular ... [more ▼]

This study proposes an efficient combination of the Discrete Element Method (DEM) and the Finite Element Method (FEM) to study the tractive performance of a rubber tire in interaction with granular terrain. The presented approach is relevant to all engineering devices interacting with granular matter which causes response forces. Herein, the extended discrete element method (XDEM) is used to describe the dynamics of the granular assembly. On the one hand, the discrete approach accounts for the motion and forces of each grain individually. On the other hand, the finite element method accurately predicts the deformations and stresses acting within the tire tread. Hence, the simulation domain occupied by the tire tread is efficiently described as a continuous entity. The coupling of both methods is based on the interface shared by the two spatially separated domains. Contact forces develop at the interface and propagate into each domain. The coupling method enables to capture both responses simultaneously and allows to sufficiently resolve the different length scales. Each grain in contact with the surface of the tire tread generates a contact force which it reacts on repulsively. The contact forces sum up over the tread surface and cause the tire tread to deform. The coupling method compensates quite naturally the shortages of both numerical methods. It further employs a fast contact detection algorithm to save valuable computation time. The proposed DEM-FEM Coupling technique was employed to study the tractive performance of a rubber tire with lug tread patterns in a soil bed. The contact forces at the tread surface are captured by 3D simulations for a tire slip of 5%. The simulations showed to accurately recapture the gross tractive effort, running resistance and drawbar pull of the tire tread in comparison to related measurements. Further, the traction mechanisms between the tire tread and the granular ground are studied by analysing the motion of the soil grains and the deformation of the tread. [less ▲]

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See detailXDEM employed to predict reduction of tungsten oxide in a dry hydrogen atmosphere
Estupinan Donoso, Alvaro Antonio UL; Peters, Bernhard UL

in International Journal of Refractory Metals & Hard Materials (2014)

Abstract The Extended Discrete Element Method (XDEM) is a novel concept to model tungsten oxides reduction. The concept extends the classical discrete element method (DEM) with additional properties such ... [more ▼]

Abstract The Extended Discrete Element Method (XDEM) is a novel concept to model tungsten oxides reduction. The concept extends the classical discrete element method (DEM) with additional properties such as the thermodynamic state. Moreover, the concept treats a solid phase represented by particles, and a fluid phase as two distinguished phases that are coupled through heat, mass and momentum transfer. hydrogen atmosphere is modelled by a direct oxygen removal from the solid oxides mechanism for which temperature and reaction progress is described by the Discrete Particle Method (DPM). An outstanding feature of the herein proposed numerical concept is that powder particles are treated as individual entities which are described by its thermodynamic state, e.g. temperature and species distribution within the particle. Therefore, it allows a detailed and accurate characterisation of isothermal literature experimentation with a high degree of accuracy. Therefore, the current approach provides a new and deep insight into the process, because particle temperatures, concentration of species and interaction of particles with the environment are inaccessible in a furnace during experiments. [less ▲]

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See detailXDEM Used for Predicting Tungsten-Oxide Reduction
Estupinan Donoso, Alvaro Antonio UL; Peters, Bernhard UL

Scientific Conference (2015, April 27)

Detailed reference viewed: 88 (8 UL)
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See detailXenocrates oder Ueber die Abgaben (Beiträge zur Geschichte der deutschsprachigen Ökonomie)
Schlosser, Johann G; Klump, Rainer UL; Priddat, Birger et al

in Xenocrates oder Ueber die Abgaben (2000)

Detailed reference viewed: 11 (0 UL)
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See detailXFEM coupling of granular flows interacting with surrounding fluids
Pasenow, F.; Zilian, Andreas UL; Dinkler, D.

in ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers (2012)

In this paper, ideas for the simulation of sliding dry granular materials interacting with surrounding fluids are presented and first results are presented. The compressible granular material is modeled ... [more ▼]

In this paper, ideas for the simulation of sliding dry granular materials interacting with surrounding fluids are presented and first results are presented. The compressible granular material is modeled as a medium which can show solid-like and fluid-like characteristics. Therefore a weighted decomposition of stress tensors of a solid-like and a fluid-like phase is applied. The surrounding incompressible fluids are described with a Newtonian constitutive model. Interface dynamics are handled with the level-set method. The model equations are discretized with the space-time finite element method. Discontinuous solution characteristics across interfaces are captured numerically by the extended finite element method (XFEM). For all discontinuities the space of ansatz functions is enriched with Heaviside functions. [less ▲]

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See detailXFEM coupling techniques for landslide-fluid interaction
Pasenow, Frithjof; Zilian, Andreas UL

Scientific Conference (2011)

Selected topographies on earth are threatened by sudden landslides on natural or artificial hillsides. Dur- ing landslides natural granular materials exhibit phase transitions from solid-like to fluid ... [more ▼]

Selected topographies on earth are threatened by sudden landslides on natural or artificial hillsides. Dur- ing landslides natural granular materials exhibit phase transitions from solid-like to fluid-like behavior [1]. In order to describe such materials interacting with surrounding fluids a material formulation allow- ing a switch from solid- to fluid-like state is developed. The solid-like state of the granular is modeled as compressible elastic material in an eulerian framework, while the surrounding fluid is described by an incompressible newtonian fluid. Discretization of the balance equations is carried out with a stabilized space-time finite element method [2]. The domain of elastic material utilizes mixed-hybrid space-time elements while for the surrounding fluid standard velocity-pressure elements [3] are used. Interaction of both continua is described with an interface-coupled formulation where the level-set technique [4] is employed for the interface motion. The challenge of the introduced model is the coupling of fields with discontinuous state variables as well as fieldwise different state variables. Available coupling techniques in the context of the extended finite element method and based on localized mixed hybrid formulations [5] will be discussed and evaluated numerically by means of selected 2D examples. [less ▲]

Detailed reference viewed: 49 (1 UL)
See detailXFEM modelling of delamination in composite materials
Cahill, L.; Natarajan, S.; McCarthy, C. et al

Scientific Conference (2010)

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See detailXFEM with global enrichment for 3D cracks
Agathos, Kostas; Chatzi, Eleni; Bordas, Stéphane UL et al

Scientific Conference (2015, June 17)

We present an extended finite element method (XFEM) based on fixed area enrichment which 1) suppresses the difficulties associated with ill-conditioning, even for "large" enrichment radii; 2) requires 50 ... [more ▼]

We present an extended finite element method (XFEM) based on fixed area enrichment which 1) suppresses the difficulties associated with ill-conditioning, even for "large" enrichment radii; 2) requires 50 times fewer enriched degrees of freedom (for a typical mesh) as the standard XFEM with geometrical enrichment (for the same or better accuracy level); 3) increases the accuracy level of the stress intensity factors and leads to "smooth" stress intensity variations along the crack front. [less ▲]

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See detailXLME interpolants, a seamless bridge between XFEM and enriched meshless methods
Amiri, F.; Anitescu, C.; Arroyo, M. et al

in Computational Mechanics (2013)

In this paper, we develop a method based on local maximum entropy shape functions together with enrichment functions used in partition of unity methods to discretize problems in linear elastic fracture ... [more ▼]

In this paper, we develop a method based on local maximum entropy shape functions together with enrichment functions used in partition of unity methods to discretize problems in linear elastic fracture mechanics. We obtain improved accuracy relative to the standard extended finite element method at a comparable computational cost. In addition, we keep the advantages of the LME shape functions, such as smoothness and non-negativity. We show numerically that optimal convergence (same as in FEM) for energy norm and stress intensity factors can be obtained through the use of geometric (fixed area) enrichment with no special treatment of the nodes near the crack such as blending or shifting. © 2013 Springer-Verlag Berlin Heidelberg. [less ▲]

Detailed reference viewed: 126 (1 UL)
See detailAn XML Format Secure protocol-OpenSST
Zhang, Xinhua UL; Jiang, Chunyan; Meinel, Christoph

in The 3rd ACS/IEEE International Conference on Computer Systems and Applications (2005)

OpenSST (Open Simple Secure Transaction) is a free software project and aims to create an efficient, open and secure alternative to the secure proprietary transaction protocol. OpenSST uses XML syntax to ... [more ▼]

OpenSST (Open Simple Secure Transaction) is a free software project and aims to create an efficient, open and secure alternative to the secure proprietary transaction protocol. OpenSST uses XML syntax to specify its message format, and relies on prevalent cryptographic algorithms to secure the transaction. OpenSST is designed to provide user with the guarantee on confidentiality, integrity, authenticity and non-repudiation. One feature of OpenSST's is that it defines a simple message structure so that it can easily be integrated into different usage frameworks. This paper mainly describes OpenSST's logic architecture and message format through an http-based prototype. [less ▲]

Detailed reference viewed: 26 (1 UL)
See detailXXIV Workshop on Geometric Methods in Physics, Bialowieza, Poland, June 26 - July 2, 2005, Proceedings Special issue of the Journal of Geometry and Symmetry in Physics, containting vol. 5 and 6
Ali, Syed Twareque UL; Gazeau, Jean-Pierre; Goldin, Gerald A. et al

Book published by Institute of Biophysics, Bulgarian Academy of Sciences (2006)

Detailed reference viewed: 14 (0 UL)
See detailXXIX workshop on geometric methods in physics, Bia\lowie\Dza Poland, June 27 -- July 3, 2010. Selected papers based on the presentations at the workshop.
Kielanowski, Piotr; Buchstaber, Victor; Anatol, Odzijewicz et al

Book published by AIP Conference Proceedings 1307. Melville, NY: American Institute of Physics (AIP). ix, 220~p. EUR~129.95/net; SFR~151.00; \sterling~95.00 \$~142.00 (2010)

The articles of this volume will be reviewed individually.

Detailed reference viewed: 23 (1 UL)
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See detailXXth ISRA World Meeting 2012 at the University of Luxembourg. Abstract Book
Scientific Program Committee and Organization Committee; Melzer, André UL

Book published by Université du Luxembourg (2012)

Detailed reference viewed: 30 (2 UL)
See detailXXVIII Workshop on Geometrical Methods in Physics, Bialowieza, Poland, 28 June - 4 July 2009
Kielanowski, Piotr; Odzijewicz, Anatol; Schlichenmaier, Martin UL

Book published by AIP (2009)

Detailed reference viewed: 20 (3 UL)
See detailY wie Ybalon
Heimböckel, Dieter UL

Article for general public (2013)

Detailed reference viewed: 31 (0 UL)
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See detailYactul: An Extensible Game-Based Student Response Framework for Active Learning
Grevisse, Christian UL; Botev, Jean UL; Rothkugel, Steffen UL

in Ponencias del XVIII Encuentro Internacional Virtual Educa, Colombia 2017 (2017)

Student response systems as an active learning strategy have shown to be useful in different study domains. With the advent of gamification, these environments have become very popular to improve student ... [more ▼]

Student response systems as an active learning strategy have shown to be useful in different study domains. With the advent of gamification, these environments have become very popular to improve student engagement. However, existing solutions only provide a static set of activity types and limit their use to classrooms. In this paper, we present Yactul, an extensible game-based student response framework for active learning. Our ecosystem fosters continuous learning both in the collaborative setting of the classroom and the private study environment of the student. Our modular architecture enables a seamless integration of activities from a broad and extensible set. In addition, a mobile app for offline learning extends the experience outside the classroom and allows to replay quizzes anywhere and anytime, track the progress of an individual learner and suggest activities on topics that require more studying. [less ▲]

Detailed reference viewed: 63 (22 UL)
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See detailYang-Mills fields and random holonomy along Brownian bridges
Arnaudon, Marc; Thalmaier, Anton UL

in Annals of Probability (2003), 31(2), 769-790

Detailed reference viewed: 99 (6 UL)