Concept

Sonar

Publications associées (46)

2D ultrasonic flow mapping of the secondary flow field in free-surface vortices

In this study, an application of two dimensional ultrasonic doppler flow mapping was undertaken on a strong full air core free-surface vortex. The vortex was generated in a scroll type vortex chamber with a subcritical approach flow which have common appli ...

2018

Remote-sensing and classification of benthic landscapes for satellite derived bathymetry

Selim Amrari

Bathymetry is a crucial variable for many researches, such as monitoring of the coral ecosystems. Traditional bathymetric measurements are made by echo-sounder, a type of sonar, measuring water depth from sea surface. Nevertheless, this acquisition process ...

2018

Wideband H-plane dielectric horn antenna

Juan Ramon Mosig, Lei Wang, Maria Garcia Vigueras, Marcos Alvarez Folgueiras

By flaring a dielectric waveguide in the H-plane, an H-plane dielectric horn is formed, which could be directly excited by an SIW feed. However, matching and radiation performances are poor due to the thinness of the substrate. To improve these performance ...

Inst Engineering Technology-Iet2017

Optimal acoustic rake receiver

Martin Vetterli, Ivan Dokmanic, Robin Scheibler

An acoustic processing method for M acoustic receivers comprising the steps of: Determining a beamforming weight vector with M weights for the M acoustic receivers based on at least one the steering vector of at least one real acoustic source, on steering ...

2016

Use of gas bubbles for ultrasound Doppler flow velocity profile measurement

Giovanni De Cesare, Tobias Meile

Ultrasonic velocimetry based on the Doppler shift effect accurately provides quasi-instantaneous flow fields for fluids with a sufficiently high acoustic scattering level. However, ultrasonic velocity instruments are known to perform poorly in clear water ...

Elsevier2016

Harnessing the damping properties of materials for high-speed atomic force microscopy

Jürgen Brugger, Georg Fantner, Adrian Pascal Nievergelt, Blake William Erickson, Jonathan David Adams, Jonas Grossenbacher

The success of high-speed atomic force microscopy in imaging molecular motors1, enzymes2 and microbes3 in liquid environments suggests that the technique could be of significant value in a variety of areas of nanotechnology. However, the majority of atomic ...

Nature Publishing Group2016

An invisible acoustic sensor based on parity-time symmetry

Romain Christophe Rémy Fleury

Sensing an incoming signal is typically associated with absorbing a portion of its energy, inherently perturbing the measurement and creating reflections and shadows. Here, in contrast, we demonstrate a non-invasive, shadow-free, invisible sensor for airbo ...

2015

Audio-based Positioning and Target Localization for Swarms of Micro Aerial Vehicles

Meysam Basiri

Swarms of autonomous MAVs show great potential in many diverse applications. In a search and rescue mission, a group of MAVs could quickly reach disaster areas by flying over obstacles, cluttered and inaccessible terrains, and work in parallel to detect an ...

EPFL2015

Scale Model Evaluation and Optimization of Sodar Acoustic Baffles

Fernando Porté Agel, Adrien Chabbey

A 21: 1 scaled sodar, operating at 40 kHz, has been built and tested in the laboratory. Sodars, which use sound scattered by turbulence to profile the lowest few hundred meters of the atmosphere, need good acoustic shielding to diminish annoyance and to re ...

American Meteorological Society2015

Satellite remote sensing of Antarctic sea-ice roughness using scatterometer data

Katherine Colby Leonard, Ernesto Trujillo Gomez

While sea-ice concentration is frequently observed from polar orbiting passive microwave satellite instruments, equivalent large-scale information on sea-ice sub-metre-scale roughness is currently unknown. Roughness on this scale is closely related to sea- ...

2014

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