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See detailWWII: Zu jung zum Erschießen
Ganschow, Inna UL

Article for general public (2018)

Der Generalstreik am 31. August 1942 war die Reaktion auf die Zwangsrekrutierung von Luxemburgern in die deutsche Wehrmacht. Beides sind Ereignisse, die das Leben Tausender auf ewig prägten – zu ihnen ... [more ▼]

Der Generalstreik am 31. August 1942 war die Reaktion auf die Zwangsrekrutierung von Luxemburgern in die deutsche Wehrmacht. Beides sind Ereignisse, die das Leben Tausender auf ewig prägten – zu ihnen gehört auch Jos Steichen, deren Jugend aus einer Reihe von Gefängnissen, Lager und Camps verbracht wurde. [less ▲]

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See detailWWII: Zwischen den Fronten
Ganschow, Inna UL

Article for general public (2018)

Paul Hamtiaux landete als Zwangsrekrutierter in der sowjetischen Gefangenschaft in einer Propaganda-Abteilung und war an der Front als Radio-Sprecher eingesetzt. Über seine Gefangenschaft ist ein ... [more ▼]

Paul Hamtiaux landete als Zwangsrekrutierter in der sowjetischen Gefangenschaft in einer Propaganda-Abteilung und war an der Front als Radio-Sprecher eingesetzt. Über seine Gefangenschaft ist ein schriftliches Dokument geblieben – das Tagebuch des russischen Hauptmanns Georgij Nemkow, der über seinen neuen Mitarbeiter relativ ausführlich berichtet. Die alten Freunde haben sich 50 Jahre später gefunden... [less ▲]

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See detailWWII: СОВЕТСКИЕ ВОЕННОПЛЕННЫЕ И ВОСТОЧНЫЕ РАБОЧИЕ В ЛЮКСЕМБУРГЕ В 1942-1944 гг.
Ganschow, Inna UL

in Ganschow, Inna (Ed.) СОЦИАЛЬНАЯ ИСТОРИЯ ВТОРОЙ МИРОВОЙ ВОЙНЫ МАТЕРИАЛЫ МЕЖДУНАРОДНОЙ КОНФЕРЕНЦИИ 26-28 августа 2016 г. (2017, September)

This publication is the first scientific treatise in the Russian language and covers the use of the labor force of Soviet prisoners of war and Eastern workers in the Luxembourg economy. The essay deals ... [more ▼]

This publication is the first scientific treatise in the Russian language and covers the use of the labor force of Soviet prisoners of war and Eastern workers in the Luxembourg economy. The essay deals with questions of demographic composi- tion, as well as living and working conditions, which until now have only been dis- cussed on the margins of two other publications on the economy of Luxembourg. Moreover, the essay deals with an unexplored theme of the repatriation of the Soviet citizens from Luxembourg after the liberation of the country in September 1944. [less ▲]

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See detail"Wy ritterliche sy dâ streit". Kloster und Burg
Margue, Michel UL

in Berg, Guy (Ed.) Man mohte schriven wal ein buch: Ergebnisse des Yolanda-Kolloquiums 26. - 27. November 1999 Luxemburg, Vianden und Ansemburg (2001)

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See detailWykorzystywanie doświadczeń, generwanie wiedzy
Borsig, Agnes; Kriszan, Michael; Sprenger, Birte UL

in Borsig, Agnes; Knappe, Elke; Kriszan, Michael (Eds.) Przekazywanie wiedzy - Wykorzystywanie doświadczeń – Inicjowanie rozwoju (2007)

This paper deals with networks for knowledge transfer in biomass and is seen as a first guideline for practitioners based on results of the INTERREG project REGIOSUSTAIN.

Detailed reference viewed: 42 (1 UL)
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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: 64 (4 UL)
See detailX wie Krux
Heimböckel, Dieter UL

Article for general public (2013)

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See detailX-Kaapi : Une nouvelle implémentation eXtrême du vol de travail
Besseron, Xavier UL; Laferriere, Christophe; Traore, Daouda et al

in Rencontres Francophones du Parallélisme (RenPar'19) (2009, September)

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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 for Tuning Lumped Models of Thermochemical Processes Involving Materials in the Powder State
Copertaro, Edoardo UL; Chiariotti, Paolo; Estupinan Donoso, Alvaro Antonio UL et al

in Engineering Journal (2016), 20(5), 187-201

Processes involving materials in gaseous and powder states cannot be modelled without coupling interactions between the two states. XDEM (Extended Discrete Element Method) is a valid tool for tackling ... [more ▼]

Processes involving materials in gaseous and powder states cannot be modelled without coupling interactions between the two states. XDEM (Extended Discrete Element Method) is a valid tool for tackling this issue, since it allows a coupled CFD- DEM simulation to be run. Such strength, however, mainly finds in long computational times its main drawback. This aspect is indeed critical in several applications, since a long computational time is in contrast with the increasing demand for predictive tools that can provide fast and accurate results in order to be used in new monitoring and control strategies. This paper focuses on the use of the XDEM framework as a tool for fine tuning a lumped representation of the non-isothermal decarbonation of a CaCO3 sample in powder state. The tuning of the lumped model is performed exploiting the multi-objective optimization capability of genetic algorithms. Results demonstrate that such approach makes it possible to estimate fast and accurate models to be used, for instance, in the fields of virtual sensing and predictive control. [less ▲]

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See detailThe XDEM Multi-physics and Multi-scale Simulation Technology: Review on DEM-CFD Coupling, Methodology and Engineering Applications
Peters, Bernhard UL; Baniasadi, Maryam UL; Baniasadi, Mehdi UL et al

in Particuology (2019), 44

The XDEM multi-physics and multi-scale simulation platform roots in the Ex- tended Discrete Element Method (XDEM) and is being developed at the In- stitute of Computational Engineering at the University ... [more ▼]

The XDEM multi-physics and multi-scale simulation platform roots in the Ex- tended Discrete Element Method (XDEM) and is being developed at the In- stitute of Computational Engineering at the University of Luxembourg. The platform is an advanced multi- physics simulation technology that combines flexibility and versatility to establish the next generation of multi-physics and multi-scale simulation tools. For this purpose the simulation framework relies on coupling various predictive tools based on both an Eulerian and Lagrangian approach. Eulerian approaches represent the wide field of continuum models while the Lagrange approach is perfectly suited to characterise discrete phases. Thus, continuum models include classical simulation tools such as Computa- tional Fluid Dynamics (CFD) or Finite Element Analysis (FEA) while an ex- tended configuration of the classical Discrete Element Method (DEM) addresses the discrete e.g. particulate phase. Apart from predicting the trajectories of individual particles, XDEM extends the application to estimating the thermo- dynamic state of each particle by advanced and optimised algorithms. The thermodynamic state may include temperature and species distributions due to chemical reaction and external heat sources. Hence, coupling these extended features with either CFD or FEA opens up a wide range of applications as diverse as pharmaceutical industry e.g. drug production, agriculture food and processing industry, mining, construction and agricultural machinery, metals manufacturing, energy production and systems biology. [less ▲]

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See detailXDEM Research on UL HPC platform
Besseron, Xavier UL

Presentation (2014, May 07)

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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)

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See detailXDEM: from HPC to the Cloud
Besseron, Xavier UL

Scientific Conference (2017, January)

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See detailXDMF and ParaView: checkpointing format
Habera, Michal UL; Zilian, Andreas UL; Hale, Jack UL et al

Scientific Conference (2018, March 21)

Checkpointing, i.e. saving and reading results of finite element computation is crucial, especially for long-time running simulations where execution is interrupted and user would like to restart the ... [more ▼]

Checkpointing, i.e. saving and reading results of finite element computation is crucial, especially for long-time running simulations where execution is interrupted and user would like to restart the process from last saved time step. On the other hand, visualization of results in thid-party software such as ParaView is inevitable. In the previous DOLFIN versions (2017.1.0 and older) these two functionalities were strictly separated. Results could have been saved via HDF5File interface for later computations and/or stored in a format understood by ParaView - VTK’s .pvd (File interface) or XDMF (XDMFFile interface). This led to data redundancy and error-prone workflow. The problem essentially originated from incompatibilities between both libraries, DOLFIN and ParaView (VTK). DOLFIN’s internal representation of finite element function is based on vector of values of degrees of freedom (dofs) and their ordering within cells (dofmap). VTK’s representation of a function is given by it’s values at some points in cell, while ordering and geometric position of these points is fixed and standardised within VTK specification. For nodal (iso- and super-parametric) Lagrange finite elements (Pk , dPk ) both representations coincide up to an ordering. This allows to extend XDMF specification and introduce intermediate way of storing finite element function - intrinsic to both, ParaView and DOLFIN. The necessary work was done as a part of Google Summer of Code 2017 project Develop XDMF for- mat for visualisation and checkpointing, see https://github.com/michalhabera/gsoc-summary. New checkpointing functionality is exposed via write checkpoint() and read checkpoint() methods. [less ▲]

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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)

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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: 75 (1 UL)