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Concept

Amortissement physique

Publications associées (30)

Flexible Support for Gas-Lubricated Bearing Bushings

Jürg Alexander Schiffmann

Herringbone-grooved journal bearings (HGJBs) for high-speed turbo-machinery are often supported on O-rings due to their favorable stiffness and damping characteristics for stability and alignment reasons. They yield limited lifetime at high temperatures, i ...

2020

Dynamic Modeling and Control of a Coupled Reforming/Combustor System for the Production of H2 via Hydrocarbon-Based Fuels

Theodoros Damartzis

The present work aims to provide insights into the dynamic operation of a coupled reformer/combustion unit that can utilize a variety of saturated hydrocarbons (HCs) with 1–4 C atoms towards H2 production (along with CO2). Within this concept, a preselecte ...

2020

Transition from Exponentially Damped to Finite-Time Arrest Liquid Oscillations Induced by Contact Line Hysteresis

François Gallaire

To clarify the role of wetting properties on the damping of liquid oscillations, we studied the decay of oscillations of liquid columns in a U-shaped tube with controlled surface conditions. In the presence of sliding triple lines, oscillations are strongl ...

AMER PHYSICAL SOC2020

Results from the Alfven Eigenmode Active Diagnostic during the 2019-2020 JET deuterium campaign

Ambrogio Fasoli, Duccio Testa, Paulo Giovane Paschoali Pereira Puglia

This paper presents results of extensive analysis of mode excitation observed during the operation of the Alfven Eigenmode Active Diagnostic (AEAD) in the JET tokamak during the 2019-2020 deuterium campaign. Six of eight toroidally spaced antennas, each wi ...

2020

From Polarizability to Effective Permittivity of Time-Varying Materials

Romain Christophe Rémy Fleury, Theodoros Koutserimpas, Mohammad Sajjad Mirmoosa

In this talk, we describe excitation of time-varying dipolar particles (time-modulated meta-atoms) by external time-varying fields from a nonstationary and causal perspective. For a time-harmonic excitation, we introduce a complex-valued function, called t ...

IEEE2020

Dynamic force coefficients identification on air-lubricated herringbone grooved journal bearing

Jürg Alexander Schiffmann, Eliott Philippe Guenat

The Narrow Groove Theory (NGT) is commonly used to simulate and design grooved gas bearing. However, measurements of dynamic force coefficients of Herringbone Grooved Journal Bearings (HGJBs) is missing, hence the validation historic NGT has never been per ...

2020

Vibration tests on interconnected timber elements using wood-wood connections

Yves Weinand, Julien Gamerro, Jean-François Bocquet

Vibration tests were performed on 3 large-scale timber slabs using wood-wood connections with a span of 8.1 meters. 10 impulsive vibration tests per specimen were performed to estimate the initial natural frequency. Vibrations were triggered using a hammer ...

2019

Gyrokinetic simulations of toroidal Alfven eigenmodes excited by energetic ions and external antennas on the Joint European Torus

Ambrogio Fasoli, Patrick Blanchard, Duccio Testa, Mikhail Maslov, Paulo Giovane Paschoali Pereira Puglia, Ling Zhou

The gyrokinetic toroidal code (GTC) has been used to study toroidal Alfven eigenmodes (TAEs) in high-performance plasmas. Experiments performed at the Joint European Torus (JET), where TAEs were driven by energetic particles arising from neutral beams, ion ...

IOP Publishing Ltd2019

Linear theory of electron-plasma waves at arbitrary collisionality

Paolo Ricci, Stephan Brunner, Rogério Manuel Cabete De Jesus Jorge

The dynamics of electron-plasma waves is described at arbitrary collisionality by considering the full Coulomb collision operator. The description is based on a Hermite–Laguerre decomposition of the velocity dependence of the electron distribution function ...

Cambridge University Press2019

Two-degrees-of-freedom (PID)-D-2 controller for precise nanopositioning in the presence of hardware-induced constant time delay

Andres San Millan Rodriguez

The fast and accurate tracking of periodic and arbitrary reference trajectories is the principal goal in many nanopositioning applications. Flexure-based piezoelectric stack driven nanopositioners are widely employed in applications where accurate mechanic ...

ELSEVIER SCIENCE INC2019