Towards quantifying effects of refractive index mismatch on PIV results

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Measuring and inducing mechanical deformation are crucial to applications in healthcare, human-machine interfaces, and soft robotics. However, conventional rigid transducers lack the flexibility, integration, and adaptability required in adaptive soft systems. Integrating sensing and actuation within multimaterial fibers and incorporating them into functional textiles offers a promising route to achieve distributed and autonomous functionality. Yet challenges persist in scalability, material processing, and

Hydraulic fracturing (HF) is a technology that consists of growing a tensile (mode I) fracture via the injection of a viscous fluid from a wellbore. It is mainly used to enhance the production of geological reservoirs of fluids but also to measure the in-situ stress field. The vertical growth of HF outside the formation of interest is a critical criterion determining the feasibility of the technique [1]. In sedimentary basins, HFs are typically observed to be contained at depth and to propagate horizontally

Drawing on the fact that the snow in an avalanche can behave like both a solid and a fluid, a young researcher at EPFL and WSL Institute for Snow and Avalanche Research SLF has managed to simulate a snow slab avalanche with unrivaled precision.

The aim of hydraulic fracturing is to create a highly conductive pathway in the reservoir formation of interest. This is typically achieved by ``propping'' the created fracture with solid particles (i.e. proppant) in order to prevent complete closure of the created fracture due to in-situ stresses when pumping stops. The placement of proppant is therefore the main goal of any fracturing treatment. It involves a number of interesting fluid dynamics problem (suspensions flow with settling, complex rheologies

The accuracy of flutter or forced response analyses of turbomachinery blade assemblies strongly depends on the correct prediction of the unsteady aerodynamic loads acting on the vibrating blades. For unsteady linearized CFD solvers, the quality of the steady-state flow solution constitutes the basis for efficient and accurate CFD unsteady computations. This paper presents the steady-state numerical and experimental results of an annular transonic compressor cascade dedicated to aeroelastic investigations. T

The aim of this master thesis is to study and develop a stabilized reduced basis method suitable for the approximation of the solution of parametrized advection-diffusion PDEs with high Péclet number, that is, roughly, the ratio between the advection coefficient and the diffusion one. Advection-diffusion equations are very important in many engineering applications, because they are used to model, for example, heat transfer phenomena or the diffusion of pollutants in the atmosphere. In such applications, we

The primary cilium, a hair-like projection from the cellular membrane, is involved in fluid flow sensing. Bending the primary cilium is known to trigger several signaling pathways. In this study, the primary cilium is modeled as a thin beam undergoing large deflection due to fluid drag forces. For the first time, the bending response is analyzed with a model combining large angle rotations with the assumption of a linear drag force along the ciliary length. In addition, the initial curvature and the angle b

Glaucoma is one of the leading causes of blindness in the world. It results in an increase of the aqueous humour (AH) outflow pathway which leads to an increase of the intraocular pressure (IOP). Many treatments exists to reduce and stabilize the IOP such as medications, filtering surgery and Glaucoma Drainage Devices. So far computational fluid dynamics (CFD) modeling of the eye drainage system has not yet been well studied. Therefore our goals was to numerically simulate the AH outflow pattern in a model

In the framework of a research project studying the influences of pumping/turbine modes on turbulence, flow fields and suspended sediments in reservoirs, prototype measurements are carried out at the Grimsel II pumped storage plant (Switzerland). In situ recordings comprise flow and velocity patterns in the lower reservoir. For the measurement of flow velocities, Acoustic Doppler Current Profiler (ADCP) devices have been fixed on the reservoir bottom in front of the intake/outlet structure. The temporal evo

The refractive index and cellular thickness information contained in the phase signal recorded by Digital Holographic Microscopy is measured independently with a dual-wavelength technique exploiting the dispersion of a dye present in the perfusion medium.

We report on a method called Digital Holographic Microscopy (DHM) for the numerical reconstruction of digital holograms taken with a microscope. It allows for simultaneous amplitude and quantitative phase contrast imaging. The reconstruction method computes the propagation of the complex optical wavefront diffracted by the object and is used to determine the refractive index and/or shape of the object with an accuracy in the nanometer range along the optical axis. A single hologram is needed for reconstruct

This thesis analyzes the properties of heavily doped nanocrystalline titanium dioxide. Thin films were deposited by magnetron sputtering with either water vapor as reactive gas or a periodically interrupted oxygen supply. The samples were at the same time electrically conducting and transparent. They consisted of mixtures of rutile, anatase and amorphous phases. Titanium dioxide is chemically stable, hard, non-toxic, transparent, and inexpensive. Due to a high refractive index it is often found in optical a

It is possible to determine the types and values of stator and rotor errors in magnetic circuits in a synchronous machine by measuring the induced voltage (ui) for the terminals of measurement loops (2) which can capture an image of the induction in the measurement gap, then by treating said signals.

In the first part, a fast and accurate method to compute the harmonic spectra of PWM modulators is presented. This method allows to compute all measurements based on the harmonics values such as the THD or FWTHD. It is especially advantageous for multilevel modulators. In the second part a new modulation method that achieves very good performances for the single-phase multilevel inverters is presented. Finally, several modulation methods are compared with the proposed measurement tool.

The author discusses the development of mathematical models for the flow of blood in the human circulatory system. By necessity, such a model of a living system must include several simplifications, ignore some factors, and make several assumptions. This is not a simple fluid flow problem with a routine application of Navier-Stoke equations. There are several chemical reactions going on, there is a coupling between the fluid flow and the motion of the vessel wall. Moreover, the material of the vessel is not

We have measured the giant magnetoimpedance (GMI) of microstructured Co-based Metglas (R) 2714a amorphous magnetic ribbons. Before micropatterning, the amorphous ribbons were chemically thinned or polished, to study the influence of sample thickness and surface state on the GMI effect. The magnetic domain structure of polished foils near saturation is observed using the bitter fluid technique. The well-defined geometry of the samples allows a quantitative comparison of the GMI effect with a simple skin dept

Summary: For the simulation of two-dimensional incompressible flows, the Navier-Stokes equations can be coupled with models of reduced complexity, such as Oseen and Stokes models. This approach is briefly reviewed here. Then we propose a numerical solution of the coupled problem by subdomain splitting. We give numerical results obtained by finite element and spectral element approximations on a couple of test problems of physical interest.

Thickness mode resonances in commercial piezoelectric ceramics have been characterised as a function of frequency by two methods. The first is based on a fit on the electrical impedance for the fundamental and the overtones. This method has been applied to a large number of PZT ceramic samples and frequency dependence for all the parameters is investigated, in particular for the piezoelectric coefficient e(33). The second is based on the measurement of the mechanical displacement at the centre of the surfac

A numerical model is presented for the simulation of complex fluid flows with free surfaces. The unknowns are the velocity and pressure fields in the liquid region, together with a function defining the volume fraction of liquid. Although the mathematical formulation of the model is similar to the volume of fluid (VOF) method, the numerical schemes used to solve the problem are different. A splitting method is used for the time discretization. At each time step, two advection problems and a generalized Stok

A FIA method has been developed and fully characterized for the simultaneous detection of ammonia and glutamine in culture media. Ammonia detection is based upon a chem. method and does not require an electrode. This species diffuses across a hydrophobic porous membrane into an indicator soln., the absorbance of which is continuously monitored using a LED and a phototransistor. Glutamine was detd. by a difference method in which ammonia was measured before and after passage through a module contg. immobiliz

Towards quantifying effects of refractive index mismatch on PIV results

Chat with Graph Search

Functional Soft Fibers and Textiles: Multi-Material Approaches for Actuation and Sensing

When, and for how long, two tough layers can contain the propagation of a fracture driven by the injection of a viscous fluid

The subtle mechanics of an avalanche – as seen in 3D

Particle laden fluids in hydraulic fracturing

Numerical and Experimental Investigations of an Annular Transonic Compressor Cascade Considering Leakage Flows

Stabilized reduced basis method for parametrized advection-diffusion PDEs

A mechanical approach to study the bending of the primary cilium in response to fluid flow

3D simulation of the aqueous flow in the eye

Influence of pumped storage operation on flow conditions near intake/outlet structures : in situ measurement using ADCP

Simultaneous Cell Morphometry and Refractive Index Measurement with Dual-Wavelength Digital Holographic Microscopy

Digital Holographic Microscopy applied to Metrology

Free carriers in nanocrystalline titanium dioxide thin films

Method and device for treating signals for detection of stator and rotor errors in magnetic circuits in a synchronous machine

A New Single-Phase Multilevel Modulator - A Fast and Accurate Method to Compute the Modulator Harmonic Spectra

Mathematical modelling of the cardiovascular system

Giant magnetoimpedance of chemically thinned and polished magnetic amorphous ribbons

Iterative solutions of multimodels for incompressible flows

Comparison of several methods to characterise the high frequency behaviour of piezoelectric ceramics for transducer applications

Numerical simulation of free surface flows

Online simultaneous monitoring of ammonia and glutamine in a hollow-fiber reactor using flow injection analysis