AWJC Nozzle simulation by 6-way coupling of DEM+CFD+FEM using preCICE coupling library

Scientific Conference (2021, June 16)

The objective of this work is to study the particle-laden fluid-structure interaction within an Abrasive Water Jet Cutting Nozzle. Such coupling is needed to study the erosion phenomena caused by the ... [more ▼]

The objective of this work is to study the particle-laden fluid-structure interaction within an Abrasive Water Jet Cutting Nozzle. Such coupling is needed to study the erosion phenomena caused by the abrasive particles inside the nozzle. So far, the erosion in the nozzle was predicted only through the number of collisions, using only a simple DEM+CFD[1] coupling. To improve these predictions, we extend our model to a 6-way Eulerian-Lagrangian momentum coupling with DEM+CFD+FEM to account for deformations and vibrations in the nozzle. Our prototype uses the preCICE coupling library[2] to couple 3 numerical solvers: XDEM[3] (for the particle motion), OpenFOAM[4] (for the water jet), and CalculiX[5] (for the nozzle deformation). XDEM handles all the particle motions based on the fluid properties and flow conditions, and it calculates drag terms. In the fluid solver, particles are modeled as drag and are injected in the momentum equation as a source term. CalculiX uses the forces coming from the fluid solver and XDEM as boundary conditions to solve for the displacements. It is also used for computing the vibrations induced by particle impacts. . The preliminary 6-way DEM+CFD+FEM coupled simulation is able to capture the complex particle-laden multiphase fluid-structure interaction inside AWJC Nozzle. The erosion concentration zones are identified and are compared to DEM+CFD coupling[1]. The results obtained are planned to be used for predicting erosion intensity in addition to the concentration zones. In the future, we aim to compare the erosions predictions to experimental data in order to evaluate the suitability of our approach. The FEM module of the coupled simulation captures the vibration frequency induced by particles and compares it with the natural frequency of the nozzle. Thus opening up opportunities for further investigation and improvement of the Nozzle design. [less ▲]

Die religiöse Dimension der Blockchain-Technologie

Presentation (2021, June 16)

Les représentations du genre dans les manuels scolaires: Une étude à l'école fondamentale luxembourgeoise

Report (2021)

Tous les jours, les enfants se servent des manuels scolaires. Mis à part leur rôle pédagogique, les manuels scolaires agissent comme instruments de socialisation et de transmission de valeurs. De ce fait ... [more ▼]

Tous les jours, les enfants se servent des manuels scolaires. Mis à part leur rôle pédagogique, les manuels scolaires agissent comme instruments de socialisation et de transmission de valeurs. De ce fait, les manuels scolaires ont le potentiel de contribuer à l’égalité entre les sexes dans nos sociétés. Nous présentons un état des lieux ainsi que des pistes possibles pour garantir l'égalité entre les sexes dans les manuels scolaires ainsi que dans les pratiques éducatives. [less ▲]

Measuring the Anisotropy in Interfacial Tension of Nematic Liquid Crystals

in Crystals (2021), 11(6), 687

<jats:p>Liquid crystal (LC) phases typically show anisotropic alignment-dependent properties, such as viscosity and dielectric permittivity, so it stands to reason that LCs also have anisotropic ... [more ▼]

<jats:p>Liquid crystal (LC) phases typically show anisotropic alignment-dependent properties, such as viscosity and dielectric permittivity, so it stands to reason that LCs also have anisotropic interfacial tensions. Measuring the interfacial tension ? of an LC with conventional methods, such as pendant drops, can be challenging, however, especially when we need to know ? for different LC aligning conditions, as is the case when we seek ??, the interfacial tension anisotropy. Here, we present measurements of ?? of the common synthetic nematic LC compound 5CB against water using a microfluidic droplet aspiration technique. To ensure tangential and normal alignment, respectively, we add poly(vinyl alcohol) (PVA) and sodium dodecylsulfate (SDS), respectively, as a stabilizer and measure ? for different concentrations of stabilizer. By fitting the Szyszkowski equation to the data, we can extrapolate to zero-stabilizer concentration, obtaining the ? of 5CB to pure water for each alignment. For normal alignment, we find ??=31.9?0.8 mN?m-1, on the order of 1 mN?m-1 greater than ?$_$=30.8?5 mN?m-1 for tangential alignment. This resonates with the empirical knowledge that 5CB aligns tangentially to an interface with pure water. The main uncertainty arises from the use of polymeric PVA as tangential-promoting stabilizer. Future improvements in accuracy may be expected if PVA can be replaced by a low molar mass stabilizer that ensures tangential alignment.</jats:p [less ▲]

Challenges, Strategies, and Perspectives for Reference-Independent Longitudinal Multi-Omic Microbiome Studies

in Frontiers in Genetics (2021)

Secure Vehicular Communications Through Reconfigurable Intelligent Surfaces

in IEEE Transactions on Vehicular Technology (2021), 70(7), 7272-7276

Reconfigurable intelligent surfaces (RIS) is considered as a revolutionary technique to improve the wireless system performance by reconfiguring the radio wave propagation environment artificially ... [more ▼]

Reconfigurable intelligent surfaces (RIS) is considered as a revolutionary technique to improve the wireless system performance by reconfiguring the radio wave propagation environment artificially. Motivated by the potential of RIS in vehicular networks, we analyze the secrecy outage performance of RIS-aided vehicular communications in this paper. More specifically, two vehicular communication scenarios are considered, i.e., a vehicular-to-vehicular (V2V) communication where the RIS acts as a relay and a vehicular-to-infrastructure (V2I) scenario where the RIS functions as the receiver. In both scenarios, a passive eavesdropper is present attempting to retrieve the transmitted information. Closed-form expressions for the secrecy outage probability (SOP) are derived and verified. The results demonstrate the potential of improving secrecy with the aid of RIS under both V2V and V2I communications. [less ▲]

Responsibility for Property and Assets Frozen or Seized by States Upon Request by the International Criminal Court

Scientific Conference (2021, June 10)

Article 57(3)(e) of the Rome Statute of the International Criminal Court empowers the International Criminal Court to ‘seek the cooperation of States pursuant to article 93, paragraph 1 (k), to take ... [more ▼]

Article 57(3)(e) of the Rome Statute of the International Criminal Court empowers the International Criminal Court to ‘seek the cooperation of States pursuant to article 93, paragraph 1 (k), to take protective measures for the purpose of forfeiture, in particular for the ultimate benefit of victims’ while Article 93(1)(k) imposes an obligation on state parties to the statute to provide assistance to the Court in the ‘identification, tracing and freezing or seizure of proceeds, property and assets and instrumentalities of crimes for the purpose of eventual forfeiture’. However, the Court does not yet have sufficient jurisprudence to flesh out the conceptual and practical boundaries of these provisions, including the question of responsibility for the management of the frozen or seized property and assets. If the Court’s very limited relevant jurisprudence is anything to go by, it is urgently necessary to interrogate these provisions and their practical application, as these questions lie at the very core of the Court’s integrity and credibility. This is especially so as the Court seeks to expand its practical reach beyond (mainly indigent) non-state actors to state actors, a situation that is likely to call more attention to the Court’s powers and responsibilities specifically relating to Articles 57(3)(e) and 93(1)(k). This article interrogates the Court’s powers under Article 57(3)(e) and the extent of obligations of the Court and state parties arising from Article 93(1)(k), and the possible implications for the rights of accused persons, the rights and expectations of victims and for state cooperation. [less ▲]

Introduction session of the Public History Summer School of the University of Wroclaw

Presentation (2021, June 07)

"Nécessité fait loi": La crise du logement et la protection des locataires dans les années 1920

Article for general public (2021)

Fundamental Education and Mediation of Human Rights in Practice: UNESCO4s First Regional Centre on Fundamental Education - CREFAL in Mexico

Presentation (2021, June 04)