Hydrostatique

L'hydrostatique, ou statique des fluides, est l'étude des fluides immobiles. Fondée par Archimède, c'est un cas de la mécanique des fluides riche d'enseignements. La pression d'un fluide est liée aux mouvements et aux chocs que les particules qu'il contient exercent sur les parois d'une enceinte. Que ce soit un liquide ou l'air atmosphérique, les chocs exercent des forces pressantes sur les parois d'une enceinte. Étymologie Le traité d'hydrostatique de Simon Stevin a paru d'abord en hollandais à Leyde en 1586 sous le titre De Beghinselen des Waterwichts. Il a été de nouveau publié dans ses œuvres mathématiques écrites, également en hollandais, à Leyde, de 1605 à 1608. Willebrord Snell les a traduites en latin. Il a rendu le hollandais Waterwichten par hydrostatice expliqué en marge par aquam ponderare et c'est par là que ce terme s'est introduit dans l'usage. Pression dans un fluide thumb|upright|Principe de Pascal : expérience d'éclatement d'un tonneau sous l

Effect of hydrostatic pressure on flow and deformation in highly reinforced particulate composites

Andreas Mortensen, Maria Gabriella Tarantino, Ludger Weber

Infiltrated particle reinforced composites combine a dense matrix with particles that are in mutual contact and can therefore transfer compressive stress directly from one particle to the next. As a result, these composites may combine characteristics of the plasticity of their matrix with those of granular matter plasticity. We measure here the influence of a 200 MPa superimposed fluid hydrostatic pressure on the flow stress of high volume fraction (56-62 vol pct) particulate Al2O3-Al composites produced by infiltration and show that the yield response of such composites is indeed pressure-sensitive. A simple analysis that transposes to metal matrix composites the theory of fluid-saturated granular media mechanics explains the phenomenon quantitatively. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Elsevier2016

Molybdenum disulphide nanoporous membranes as nanofluidic platforms - large-area engineering and study

Michal Daniel Macha

The work demonstrated in this thesis represent the path towards developing the large-scale fabrication of two-dimensional nanoporous membrane devices and use thereof as platforms to study nanoscale physics of water and ion flow through confined channels. Methods developed here are used to fabricate molybdenum disulfide (MoS2) membrane devices and investigate the fundamental physics of nanopore systems and thin films in aqueous solutions. In particular, the second chapter presents the accomplishments in the large-area MoS2 synthesis via chemical vapor deposition. Process modifications such as the use of spin-coated precursors/growth promoters and addition of active gases such as H2O vapor or moderate amount of O2 enable to scale up the growth reaction into the synthesis of a continuous monolayer films on 2-, 3- and 4-inch substrates. Third chapter shows the application of focused ion beam irradiation for engineering, imaging and studying optically active defects in MoS2 and hexagonal boron nitride films. On top of that, the ion irradiation protocol was used for establishing the tunable and large-throughout nanopore drilling process on suspended MoS2 membranes. With the high-resolution, scanning electron transmission microscopy, nanopores were investigated with an analysis script and classified based on the pore geometries and edge composition. Coupled with molecular dynamics simulations the membranes populated with ~1nm nanopores were assessed in the context of emerging ion- and water- permeation properties. The last, fourth chapter presents the application of nanoporous membranes discussed in previous chapters in the nanofluidics study application. A particular emphasis is put on the application of hydrostatic pressure in nanopore experiments as an additional measurement probe. Experimental results shown in this chapter uncover the non-linear signals originating from nanobubbles pinning, improper wetting and membrane adhesion issues. With the assistance of hydrostatic pressure, the nanoporous MoS2 suspended membranes are then further investigated to explore the ion transport properties and nanopores behaviour under applied strain in the context of artificial mechanosensing as well as osmotic power generation in salinity gradients.The ion irradiated, atomically thin films proved to be a highly attractive membrane materials and demonstrated a great promise in broad nanofluidic applications. Insights acquired during the thesis study were used to advance the state-of-art knowledge in field of the synthesis and application of 2D membranes in the nanofluidics research.

EPFL2022

Molybdenum disulphide nanoporous membranes as nanofluidic platforms - large-area engineering and study

Michal Daniel Macha

EPFL2022

Effect of hydrostatic pressure on flow and deformation in highly reinforced particulate composites

Molybdenum disulphide nanoporous membranes as nanofluidic platforms - large-area engineering and study

A modified delay-time method for statics estimation with the virtual refraction

A modified delay-time method for statics estimation with the virtual refraction

Effect of hydrostatic pressure on flow and deformation in highly reinforced particulate composites

Molybdenum disulphide nanoporous membranes as nanofluidic platforms - large-area engineering and study