Publications associées à Variété stable

Stability: a search for structure

In this thesis we study stability from several viewpoints. After covering the practical importance, the rich history and the ever-growing list of manifestations of stability, we study the following. (i) (Statistical identification of stable dynamical syste ...

EPFL2024

Stability of a liquid layer draining around a horizontal cylinder: Interplay of capillary and gravity forces

François Gallaire, Shahab Eghbali, Simeon Vladimirov Djambov

We study the drainage of a viscous liquid film coating the outside of a solid horizontal cylinder, where gravity acts vertically. We focus on the limit of large Ohnesorge numbers Oh, where inertia is negligible compared to viscous effects. We first study t ...

Amer Physical Soc2024

Controlling the crystal structure of succinic acid via microfluidic spray-drying

Esther Amstad, Aysu Ceren Okur

Many properties of materials, including their dissolution kinetics, hardness, and optical appearance, depend on their structure. Unfortunately, it is often difficult to control the structure of low molecular weight organic compounds that have a high propen ...

ROYAL SOC CHEMISTRY2023

Kinetics of information scrambling in correlated metals: Disorder-driven transition from shock wave to Fisher or Kolmogorov-Petrovsky-Piskunov dynamics

Camille Didier Georges Aron

Quenched disorder slows down the scrambling of quantum information. Using a bottom-up approach, we formulate a kinetic theory of scrambling in a correlated metal near a superconducting transition, following the scrambling dynamics as the impurity scatterin ...

Amer Physical Soc2023

The dynamics of unsteady frictional slip pulses

Thibault Didier Roch, Fabian Barras

Self-healing slip pulses are major spatiotemporal failure modes of frictional systems, featuring a characteristic size L(t) and a propagation velocity c(p)(t) (t is time). Here, we develop a theory of slip pulses in realistic rate- and state-dependent fric ...

National Academy of Sciences2023

Study on the possibility of Φ-OTDR sensing in hollow-core fibres

Luc Thévenaz, Malak Mohamed Hossameldeen Omar Mohamed Galal, Yuting Yang

The backscattering process in hollow core fibres shows a large similarity with Rayleigh scattering, offering the potential to be exploited for distributed sensing. A classical Φ-OTDR implementation is used to observe the backscattering signal from the surf ...

SPIE2023

Gyrokinetic simulation of short wavelength ion temperature gradient instabilities in the ADITYA-U tokamak

Laurent Villard, Emmanuel Lanti

In this work, linear and nonlinear collisionless electrostatic simulation studies of the standard and short wavelength ion temperature gradient mode (SWITG) for experimental profiles and parameters of ADITYA-U tokamak are performed using the linear global ...

IOP Publishing Ltd2023

Microscopic picture of paraelectric perovskites from structural prototypes

Nicola Marzari, Giovanni Pizzi, Michele Kotiuga, Boris Kozinsky

We highlight with first-principles molecular dynamics the persistence of intrinsic < 111 > Ti off-centerings for BaTiO3 in its cubic paraelectric phase. Intriguingly, these are inconsistent with the Pm (3) over barm space group often used to atomistically ...

AMER PHYSICAL SOC2022

Whirling instability of an eccentric coated fibre

François Gallaire, Edouard Boujo, Shahab Eghbali, Ludovic Pierre Gustave Keiser

We study a gravity-driven viscous flow coating a vertical cylindrical fibre. The destabilisation of a draining liquid column into a downward moving train of beads has been linked to the conjunction of the Rayleigh-Plateau and Kapitza instabilities in the l ...

Cambridge University Press2022

Invariant tori in dissipative hyperchaos

Tobias Schneider, Jeremy Peter Parker

One approach to understand the chaotic dynamics of nonlinear dissipative systems is the study of non-chaotic yet dynamically unstable invariant solutions embedded in the system's chaotic attractor. The significance of zero-dimensional unstable fixed points ...

American Institute of Physics2022

A geographical study of (M)over-bar(2)(P-2, 4)(main)

Francesca Carocci

We discuss criteria for a stable map of genus two and degree 4 to the projective plane to be smoothable, as an application of our modular desingularisation of (M) over bar (2,n)(P-r, d)(main) via logarithmic geometry and Gorenstein singularities. ...

WALTER DE GRUYTER GMBH2022

Evidence of a transient phase during the hydrolysis of calcium-deficient hydroxyapatite

Jacques Lemaître

In the present paper, calcium deficient hydroxyapatite (Ca-def OHAP) has been examined in a transmission electron microscope. During the observation, the initial Ca-def OHAP was seen to transform first into a transient intermediate phase, then to a final, ...

WALTER DE GRUYTER GMBH2022

High Li-ion conductivity in tetragonal LGPO: A comparative first-principles study against known LISICON and LGPS phases

Nicola Marzari, Giuliana Materzanini, Aris Marcolongo, Leonid Kahle

We highlight fast Li-ion diffusion in hypothetical tetragonal Li10GeP2O12 (LGPO), as a counterpart to the well-known phases of orthorhombic (LISICON) LGPO, thio-LISICON, and tetragonal Li10GeP2S12 (LGPS). We use extended Car-Parrinello molecular dynamics i ...

AMER PHYSICAL SOC2021

Periodic orbits exhibit oblique stripe patterns in plane Couette flow

Tobias Schneider, Florian Reetz

Spatiotemporally chaotic dynamics of transitional plane Couette flow may give rise to regular turbulent-laminar stripe patterns with a large-scale pattern wavelength and an oblique orientation relative to the laminar flow direction. A recent dynamical syst ...

AMER PHYSICAL SOC2021

Effects of spanwise confinement on stratified shear instabilities

François Gallaire, Yves-Marie François Ducimetière

We consider the influence of transverse confinement on the instability properties of velocity and density distributions reminiscent of those pertaining to exchange flows in stratified inclined ducts, such as the recent experiment of Lefauve et al. [J. Flui ...

2021

Second-order adjoint-based sensitivity for hydrodynamic stability and control

Edouard Boujo

Adjoint-based sensitivity analysis is routinely used today to assess efficiently the effect of open-loop control on the linear stability properties of unstable flows. Sensitivity maps identify regions where small-amplitude control is the most effective, i. ...

Cambridge University Press2021

Learning to Hit: A statistical Dynamical System based approach

Aude Billard, Michael Bosongo Bombile, Harshit Khurana

This paper proposes a manipulation scheme based on learning the motion of objects after being hit by a robotic end-effector. This allows for the object to be positioned at a desired location outside the physical workspace of the robot. An estimate of the o ...

IEEE2021

Atomistic origins of the limited phase stability of Cs+-rich FAxCs(1-x)PbI3 mixtures

Michael Graetzel, David Lyndon Emsley, Ursula Röthlisberger, Ariadni Boziki, Simone Meloni, Dominik Józef Kubicki, Aditya Mishra

Mixed cation perovskites, [HC(NH2)2]xCs(1-x)PbI3, (FAxCs(1-x)PbI3) with x=0.8 achieve high solar cell power conversion efficiencies (PCEs) while exhibiting long-term stability under ambient conditions. In this work, we perform density functional theory (DF ...

2020

Horizontal transport under wind-induced resonance in stratified waterbodies

Alfred Johny Wüest, Hugo Nicolás Ulloa Sánchez, Serban George Constantinescu, Kyoung Sik Chang

Periodic winds acting on a stratified waterbody can amplify normal modes of motion and enhance the basin-scale circulation via resonance. Here, we use idealized largeeddy simulations to investigate the flow features and quantify the horizontal transport in ...

2020

The Synergism of DMSO and Diethyl Ether for Highly Reproducible and Efficient MA(0.5)FA(0.5)PbI(3)Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Hiroyuki Kanda, Tom Theodorus Antonius Lummen, Yi Zhang, Yonghui Lee, Keith Gregory Brooks, Ruiyuan Hu, Min Chen

Composition and film quality of perovskite are crucial for the further improvement of perovskite solar cells (PSCs), including efficiency, reproducibility, and stability. Here, it is demonstrated that by simply mixing 50% of formamidinium (FA(+)) into meth ...

2020