Publications associées à À-coup

Paradoxical simulation results of chaos-like chattering in the bouncing ball system

This paper reports and investigates paradoxical simulation results of the bouncing ball system. Chaos-like motion of the bouncing ball system with intermittent chattering (Zeno behavior) is observed in simulations if the relative acceleration of the table ...

ELSEVIER2021

Mean-field dynamics of infinite-dimensional particle systems: global shear versus random local forcing

Elisabeth Agoritsas

In infinite dimensions, many-body systems of pairwise interacting particles provide exact analytical benchmarks for the features of amorphous materials, such as the stress--strain curve of glasses under quasistatic shear. Here, instead of global shear, we ...

2021

Physical Mechanism and Flow Control of Tip Vortex Cavitation

Ali Amini

Occurrence of cavitation in hydraulic machines is a challenging issue because it is often accompanied with loss of efficiency, noise emissions, vibrations, and erosion damages. Tip vortices, in particular, are an ideal site for the development of cavitatio ...

EPFL2020

Shapes of rotating normal fluid He-3 versus superfluid He-4 droplets in molecular beams

Christoph Bostedt, Andre Al Haddad

Previous single-pulse extreme ultraviolet and x-ray coherent diffraction studies revealed that superfluid He-4 droplets obtained in a free jet expansion acquire sizable angular momentum, resulting in significant centrifugal distortion. Similar experiments ...

AMER PHYSICAL SOC2020

Explicit dynamic approach for unbounded domains in frictional contact with Rate and State laws

Jean-François Molinari, Roozbeh Rezakhani

The paper explores the ability of an explicit time integration procedure to simulate the dynamics of shear rupture between unbounded elastic blocks on frictional interface, modeled with the finite element method. The behaviour of the interface is governed ...

ELSEVIER2020

Paradoxical Chaos-Like Chattering In The Bouncing Ball System

Kilian Schindler

This paper reports and investigates paradoxical simulation results of the bouncing ball system. Chaos-like motion of the bouncing ball system with intermittent chattering (Zeno behaviour) is observed in simulations if the relative acceleration of the table ...

AMER SOC MECHANICAL ENGINEERS2018

Range-based underwater target localization using an autonomous surface vehicle: Observability analysis

In the field of marine robotics, the problem of range based underwater target localization can be defined as that of localizing an unknown - fixed or moving - target from a surface vehicle called the tracker, using range information available about the tar ...

2018

Gravity-Insensitive Flexure Pivot Oscillators

Simon Nessim Henein, Ilan Vardi, Etienne Frédéric Gabriel Thalmann, Lennart Rubbert, Mohammad Hussein Kahrobaiyan

Classical mechanical watch plain bearing pivots have frictional losses limiting the quality factor of the hairspring-balance wheel oscillator. Replacement by flexure pivots leads to a drastic reduction in friction and an order of magnitude increase in qual ...

2018

Rotational stiffness of web-flange junctions of pultruded GFRP decks

Thomas Keller, Julia De Castro San Roman Fest, Sonia Yanes Armas

The rotational behavior of the web-flange junctions (WFJs) of a pultruded glass fiber-reinforced polymer (GFRP) bridge deck system with trapezoidal cell cross-sectional geometry was investigated. The rotational response of three WFJ types, in two bending m ...

Elsevier2017

Multi-segment analysis of spinal kinematics during sit-to-stand in patients with chronic low back pain

Julien Favre, Thomas Legrand, Guillaume Christe

While alterations in spinal kinematics have been frequently reported in patients with chronic low back pain (CLBP), a better characterization of the kinematics during functional activities is needed to improve our understanding and therapeutic solutions fo ...

Elsevier Sci Ltd2016

Motion-based nearest vector metric for reference frame selection in the perception of motion

Michael Herzog, Aaron Michael Clarke

We investigated how the visual system selects a reference frame for the perception of motion. Two concentric arcs underwent circular motion around the center of the display, where observers fixated. The outer (target) arc's angular velocity profile was mod ...

Association for Research in Vision and Ophthalmology (ARVO)2016

Closed-loop magnetic bearing and angular velocity control of a reaction sphere actuator

Yves Perriard, Leopoldo Rossini

This article presents the first closed-loop magnetic bearing and angular velocity experimental results of a reaction sphere actuator for satellite attitude control. The proposed reaction sphere is a permanent magnet spherical actuator whose rotor is suppor ...

Pergamon-Elsevier Science Ltd2015

Performance analysis of jump-gliding locomotion for miniature robotics

Dario Floreano, Mirko Kovac, Jean-Christophe Zufferey

Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes ...

Iop Publishing Ltd2015

Empirical and analytical analyses of laboratory granular flows to investigate rock avalanche propagation

Vincent Labiouse, Irene Manzella

Laboratory experiments which consist of releasing dry rigid non-cohesive grains or small bricks on an unconfined chute have been designed to investigate rock avalanche propagation mechanisms and to identify parameters influencing their deposit characterist ...

Springer Verlag2013

Traveling-wave deceleration of heavy polar molecules in low-field-seeking states

Andreas Osterwalder

We demonstrate the deceleration of heavy polar molecules in low-field-seeking states by combining a cryogenic source and a traveling-wave Stark decelerator. The cryogenic source provides a high-intensity beam with low speed and temperature, and the traveli ...

American Physical Society2012

Collision-Free Intersection Crossing of Mobile Robots Using Decentralized Navigation Functions on Predefined Paths

Denis Gillet, Laleh Makarem, Benjamin Fankhauser

This paper deals with the coordination of a group of mobile robots at an intersection. It focusses on decentralized navigation functions (DNFs) to achieve efficient traffic control. The main challenge is to define virtual potentials, which are used by dece ...

2011

Evaluation of a mixed approach combining stationary and wearable systems to monitor gait over long distance

Kamiar Aminian, Julien Favre, Xavier Crevoisier

Thanks to decades of research, gait analysis has become an efficient tool. However, mainly due to the price of the motion capture systems, standard gait laboratories have the capability to measure only a few consecutive steps of ground walking. Recently, w ...

Elsevier2010

Two degrees of freedom miniaturized gyroscope based on active magnetic bearings

Thomas Bosgiraud

The introduction of the active blocking system, better known as ABS, into cars revealed the growing need for inertial sensing. Among other data, that permit to apprehend the movements of a vehicle, the measurement of the vehicle angular velocity describes ...

EPFL2008