Publications related to Gauge Transformations, Twisted Poisson Brackets and Hamiltonization of Nonholonomic Systems

CosmoLattice: A modern code for lattice simulations of scalar and gauge field dynamics in an expanding universe

Adrien Florio, Wessel Valkenburg, Daniel Garcia Figueroa, Francisco Torrenti

This paper describes CosmoGattice, a modern package for lattice simulations of the dynamics of interacting scalar and gauge fields in an expanding universe. CosmoGattice incorporates a series of features that makes it very versatile and powerful: i) it is ...

ELSEVIER2023

Unraveling looping efficiency of stochastic Cosserat polymers

Giulio Corazza, Raushan Singh

Understanding looping probabilities, including the particular case of ring closure or cyclization, of fluctuating polymers (e.g., DNA) is important in many applications in molecular biology and chemistry. In a continuum limit the configuration of a polymer ...

AMER PHYSICAL SOC2022

Buoyancy-driven convection of droplets on hot nonwetting surfaces

François Gallaire, Eunok Yim

The global linear stability of a water drop on hot nonwetting surfaces is studied. The droplet is assumed to have a static shape and the surface tension gradient is neglected. First, the nonlinear steady Boussinesq equation is solved to obtain the axisymme ...

AMER PHYSICAL SOC2021

Structure-Preserving Reduced Basis Methods For Poisson Systems

Cecilia Pagliantini, Jan Sickmann Hesthaven

We develop structure-preserving reduced basis methods for a large class of nondissipative problems by resorting to their formulation as Hamiltonian dynamical systems. With this perspective, the phase space is naturally endowed with a Poisson manifold struc ...

AMER MATHEMATICAL SOC2021

Topology design of general tensegrity with rigid bodies

Yafeng Wang

This study presents a general approach to the topology design of tensegrities with rigid bodies. To the best of the authors' knowledge, all existing topology design methods of tensegrities focus on tensegrities that only consist of members carrying axial f ...

2020

Rigid foldability and mountain-valley crease assignments of square-twist origami pattern

Huijuan Feng

Rigid foldability allows an origami pattern to fold about crease lines without twisting or stretching component panels. It enables folding of rigid materials, facilitating the design of foldable structures. Recent study shows that rigid foldability is affe ...

PERGAMON-ELSEVIER SCIENCE LTD2020

High-order based revelation of bifurcation of novel Schatz-inspired metamorphic mechanisms using screw theory

Huijuan Feng

The revelation of mechanism bifurcation is essential in the design and analysis of reconfigurable mechanisms. The first- and second-order based methods have successfully revealed the bifurcation of mechanisms. However, they fail in the novel Schatz-inspire ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Inkjet Printing of Complex Soft Machines with Densely Integrated Electrostatic Actuators

Samuel Rosset, Herbert Shea, Samuel Schlatter, Giulio Grasso

A multimaterial inkjet printing method for integrated soft multifunctional machines is reported, combining dense arrays of electrostatic actuators, multilayer electrical routing, and complex networks of microfluidic channels in one printing process. Most a ...

2020

Robot skills learning with Riemannian manifolds: Leveraging geometry-awareness in robot learning, optimization and control

Noémie Laure Gwendoline Jaquier

Humans exhibit outstanding learning and adaptation capabilities while performing various types of manipulation tasks. When learning new skills, humans are able to extract important information by observing examples of a task and efficiently refine a priori ...

EPFL2020

A priori error for unilateral contact problems with Lagrange multipliers and isogeometric analysis

Annalisa Buffa, Mathieu Jonathan Fabre, Pablo Antolin Sanchez

In this paper, we consider unilateral contact problem without friction between a rigid body and deformable one in the framework of isogeometric analysis. We present the theoretical analysis of the mixed problem. For the displacement, we use the pushforward ...

2019

Inertial manipulation of bubbles in rectangular microfluidic channels

Demetri Psaltis, Gioele Mariano Nicolò Balestra, François Gallaire, Seyyed Mohammad Hosseini Hashemi, Miguel Antonio Modestino, Lailai Zhu, Pooria Hadikhani

Inertial microfluidics is an active field of research that deals with crossflow positioning of the suspended entities in microflows. Until now, the majority of the studies have focused on the behavior of rigid particles in order to provide guidelines for m ...

2018

The isostatic 3-body problem: a complete solution

Simon Nessim Henein, François Barrot, Florent Cosandier, Johannes Richard Cornelis Geerit Kruis, Ilan Vardi

Kinematic couplings are used when two rigid bodies need to be repeatedly and accurately positioned with respect to each other. They allow for sub-micron positioning repeatability by suppressing play and reducing strains in the bodies. Typical applications ...

2017

A multisymplectic integrator for elastodynamic frictionless impact problems

Mathieu Desbrun, Tudor Ratiu, François Gay-Balmaz, François Marie Alain Demoures, Alejandro Marcos Aragon

We present a structure preserving numerical algorithm for the collision of elastic bodies. Our integrator is derived from a discrete version of the field-theoretic (multisymplectic) variational description of nonsmooth Lagrangian continuum mechanics, combi ...

Elsevier2017

Ion heating and flows in a high power helicon source

Alan Howling, Ivo Furno, Gennady Plyushchev, Rémy Jacquier, Riccardo Agnello

We report experimental measurements of ion temperatures and flows in a high power, linear, magnetized, helicon plasma device, the Resonant Antenna Ion Device (RAID). Parallel and perpendicular ion temperatures on the order of 0.6 eV are observed for an rf ...

Amer Inst Physics2017

Assessment of the lower limb soft tissue artefact at marker-cluster level with a high-density marker set during walking

Kamiar Aminian, Arnaud Barré

The estimation of joint kinematics from skin markers is hindered by the soft tissue artefact (STA), a well-known phenomenon although not fully characterized. While most assessments of the STA have been performed based on the individual skin markers displac ...

Elsevier2017

The Geometric Nature of the Flaschka Transformation

Tudor Ratiu, François Gay-Balmaz

We show that the Flaschka map, originally introduced to analyze the dynamics of the integrable Toda lattice system, is the inverse of a momentum map. We discuss the geometrical setting of the map and apply it to the generalized Toda lattice systems on semi ...

Springer Verlag2017

Design, analysis, testing and applications of two-body and three-body kinematic mounts

Johannes Richard Cornelis Geerit Kruis

Kinematic couplings are used when two rigid bodies need to be repeatedly and accurately positioned with respect to each other. They allow for sub-micron positioning repeatability by suppressing play and reducing strains in the bodies. Typical applications ...

EPFL2016

Effect of static and kinematic boundary conditions on the out-of-plane response of brick masonry walls

Katrin Beyer, Filippo Lucca

The Unreinforced Wall (URM) elements that are most susceptible to out-of-plane failure are wall elements of the upper storeys where the accelerations are largest. In modern URM buildings with reinforced concrete slabs, the out-of-plane mechanism involves t ...

Taylor and Francis Group2016

On the statistical physics of chains and rods, with application to multi-scale sequence-dependent DNA modelling

Alexandre Emmanuel Grandchamp

The complex mechanisms involved in cellular processes have been increasingly understood this past century and the central role of the DNA molecule has been recognized. The base pair sequence along a DNA fragment is observed not only to encode the genomic i ...

EPFL2016

Muscle Moment-Arms: A Key Element in Muscle-Force Estimation

Philippe Müllhaupt, Alexandre Terrier, Alain Farron, David Ingram, Christoph Anselm Engelhardt

A clear and rigorous definition of muscle moment-arms in the context of musculoskeletal systems modelling is presented, using classical mechanics and screw theory. The definition provides an alternative to the tendon excursion method, which can lead to inc ...

Taylor & Francis2015