Publications associées à Detailed experiments on weakly deformed cavitation bubbles

Interactions of Cavitation Bubbles with Deformable Interfaces

Cavitation is a topic that has long been of interest due to the large and growing range of applications associated with it. This is mainly because the collapse of cavitation bubbles releases a considerable amount of energy into the surrounding environment. ...

EPFL2023

Effect of femtosecond laser-induced high pressure on fused silica polymorphism

Arunkrishnan Radhakrishnan

High-pressure studies in silica are of great interest to earth and planetary sciences. Highpressure phases are rarely found in nature as a result of shock events like meteorite impacts or volcanic events in nature. Recreating these phases remains a challen ...

EPFL2022

Thermally activated flow in models of amorphous solids

Marko Popovic, Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus

Amorphous solids yield at a critical value Sigma(c) of the imposed stress Sigma through a dynamical phase transition. While sharp in athermal systems, the presence of thermal fluctuations leads to the rounding of the transition and thermally activated flow ...

AMER PHYSICAL SOC2021

Determination of the internal piezoelectric potentials and indium concentration in InGaN based quantum wells grown on relaxed InGaN pseudo-substrates by off-axis electron holography

Victor Carle Adrien Boureau

Micro light emitting diodes have been grown by metal organic vapor phase epitaxy on standard GaN and partly relaxed InGaNOS substrates with the purpose of incorporating higher concentrations of indium for identical growth conditions. Green emission has bee ...

2020

Shock waves from nonspherical cavitation bubbles

Mohamed Farhat, Danail Obreschkow, Nicolas Dorsaz, Philipp Kobel, Marc Tinguely, Outi Supponen

We present detailed observations of the shock waves emitted at the collapse of single cavitation bubbles using simultaneous time-resolved shadowgraphy and hydrophone pressure measurements. The geometry of the bubbles is systematically varied from spherical ...

Amer Physical Soc2017

Collapse phenomena of deformed cavitation bubbles

Outi Supponen

Cavitation bubbles are a topic of long-standing interest owing to the powerful phenomena associated with their collapse. Their unique ability to focus energy typically causes damage in hydraulic machinery (turbines, pumps, propellers, ...) but, if managed ...

EPFL2017

Signal analysis of an actively generated cavitation bubble in pressurized pipes for detection of wall stiffness drops

Giovanni De Cesare, Anton Schleiss, Mohamed Farhat, Fadi Hachem, Alexandre Jean Pachoud

Due to the increasing production of volatile new renewable energies as solar and wind, storage hydropower plants have to operate under harsh operation conditions in order to stabilize the electricity grid. As a result, highly transient water pressures occu ...

Elsevier2016

Towards an incoherent off-axis digital holographic microscope

Frédéric Montfort, Christian Depeursinge

We propose and experimentally demonstrate a system in which off-axis digital holographic microscopy is realized using a broadband illumination source. Single-shot holographic measurements are enabled, while the coherence noise is removed thanks to the broa ...

Spie-Int Soc Optical Engineering2015

Optical microscopy for imaging through scattering media

Xin Yang

Optical microscopy has been widely used in the life sciences and biological research for several decades. It possesses many advantages over x-ray radiography, computed tomography, ultrasound imaging and magnetic resonance imaging, in terms of being low cos ...

EPFL2014

Axial phase measurements of light interacting with microstructures

Hans Peter Herzig, Myun Sik Kim, Toralf Scharf

We present an experimental method to study field structures of highly confined light after interaction with microstructures. A high-resolution interference microscope (HRIM) allows us to measure the three-dimensional (3D) amplitude and phase distributions ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2012

Monitoring of Steel Lined Pressure Shafts Considering Water-Hammer Wave Signals and Fluid-Structure Interaction

Fadi Hachem

In the past, the safety margin for dynamic water pressure loads in steel-lined pressure tunnels and shafts was considered as acceptable by using conventional design safety factors. Due to high peak energy demands, existing plants are operating nowadays und ...

EPFL2011

A review of wave celerity in frictionless and axisymmetrical steel-lined pressure tunnels

Anton Schleiss, Fadi Hachem

Generally applicable approaches for estimating the‘‘quasi-static’’, which means without fluid–structure interaction and frequency-dependent water-hammer wave speed in steel-lined pressure tunnels are analyzed. The external constraints and assumptions of th ...

Elsevier2011

A method and apparatus for enhanced spatial bandwidth wavefronts reconstructed from digital interferograms or holograms

Christian Depeursinge, Michaël Unser, Nicolas Pavillon, Chandra Sekhar Seelamantula

The present invention discloses a method and an apparatus to compute a complex wavefield, referred to as the object wave o, by means of measuring the intensity signal resulting from the interference of the said object wave with a second wave termed the ref ...

2010

Digital holographic reflectometry

Tristan Colomb, Christian Depeursinge, Jonas Kühn, Nicolas Pavillon, Ahmet Ata Akatay

Digital holographic microscopy (DHM) is an interferometric technique that allows real-time imaging of the entire complex optical wavefront (amplitude and phase) reflected by or transmitted through a sample. To our knowledge, only the quantitative phase is ...

2010

Time-resolved x-ray diffraction study of laser-induced shock and acoustic waves in single crystalline silicon

A rod of single crystalline silicon has been subjected to high-power nanosecond laser pulses inducing ultrasonic and shock waves traveling into the bulk of the material. Stroboscopic time-resolved high-energy x-ray diffraction measurements were carried out ...

2009

Governing the speed of a light signal in optical fibers : Brillouin slow and fast light

Sang Hoon Chin

Dynamic control of the speed of a light signal, based on stimulated Brillouin scattering in optical fibers, was theoretically studied and also experimentally demonstrated as the core object of this thesis. To date, slow light based on stimulated Brillouin ...

EPFL2009

Shot noise, refractive index tomography and aberrations estimation in digital holographic microscopy

Florian Charrière

The present thesis develops some specific aspects of digital holographic microscopy (DHM), namely the effect of shot noise on the phase image accuracy, the use of DHM in micro-tomography and in aberrations evaluation of a microscope objective (MO). DHM is ...

EPFL2007

Interaction of a cavitation bubble with a spherical free surface

Mohamed Farhat, Danail Obreschkow, Nicolas Dorsaz, Philipp Kobel, Aurèle De Bosset

The dynamic of a cavitation bubble inside a water drop is investigated in microgravity in order to analyze the interaction between the collapsing bubble and a quasispherical free surface. Tests are carried in the frame of the 42nd parabolic flight campaign ...

2006

Tomography using multiple wavelengths in digital holographic microscopy

Frédéric Montfort

This thesis presents a new tomographic imaging method using multiple wavelengths in digital holographic microscopy. It is based on the addition of several reconstructed wavefronts measured at different wavelengths. The resulting diffraction tomographic vis ...

EPFL2006

Light dosimetry for photodynamic therapy in the esophagus

Hubert van den Bergh, Georges Wagnières

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) is an efficient technique to treat superficial early cancers in the pharynx, esophagus, and tracheo-bronchial tree. However, the lack of selectivity of some of the clinically used photosensitizers can re ...

1997