Publications associées à Histoire du mètre

High density fiber postitioner system for massive spectroscopic surveys

Hannes Bleuler, Jean-Paul Richard Kneib, Mohamed Bouri, Luzius Gregor Kronig, Philipp Hörler

We describe here a novel design of a fast high-density robotized fiber positioner system for massive spectroscopic surveys. The fiber positioners are compact, robust, and they can be coordinated, allowing for a high spatial density. Furthermore, the high a ...

OXFORD UNIV PRESS2018

Influence of geometrical imperfections and flaws at welds of steel liners on fatigue behavior of pressure tunnels and shafts in anisotropic rock

Alexandre Jean Pachoud

The recent development of high-strength (HSS) weldable steels has enlarged the range of design alternatives for the optimization of high-head steel-lined pressure tunnels and shafts (SLPT&S) in the hydropower industry. With the liberalization of the Europe ...

EPFL2017

Surge Wave Propagation in a Common Tailrace Channel for Two Large Pumped-Storage Plants

Anton Schleiss, Giovanni De Cesare, Martin Peter Bieri, Stéphane Christian Olivier Terrier

Sudden starting and stopping of turbines and pumps lead to highly unsteady flow in tailrace channels of hydropower plants (HPP). Submergence of Pelton turbines and air entrainment in pumps due to surge waves must be avoided by technical measures. The exist ...

Asce-Amer Soc Civil Engineers2014

Design of the new METAS watt balance experiment Mark II

Reymond Clavel, Florent Cosandier

The kilogram is the last unit of the international system of units (SI) still based on a material artefact, the international prototype of the kilogram (IPK). The comparisons made in the last hundred years have clearly revealed a long-term relative drift b ...

Iop Publishing Ltd2013

Prediction of a Francis turbine prototype full load instability from investigations on the reduced scale model

François Avellan, Pierre Maruzewski, Sébastien Alligné

The growing development of renewable energies combined with the process of privatization, lead to a change of economical energy market strategies. nstantaneous pricings of electricity as a function of demand or predictions, induces profitable peak producti ...

International Association For Hydraulic Research2010

Method and apparatus for 3d object shape and surface topology measurements by contour depth extraction acquired in a single shot

Christian Depeursinge, Daniel Boss, Yves Delacrétaz

The invention relates to a method and apparatus for topological or shape measurement of objects of any size, by using an interferometric technique comprising an optical source, with selectable coherence, allowing contouring from single shot interferograms ...

2010

Unsteady CFD Prediction of von Kármán Vortex Shedding in Hydraulic Turbine Stay Vanes

François Avellan, Mohamed Farhat, Philippe Ausoni

All hydraulic turbines containing a casing with stay vanes face the potential dynamic problem of stay vane von Kármán vortex shedding. For hydraulic efficiency purposes the stay vanes tend to be relatively slender in the direction normal to the flow thus b ...

2007