Publications related to Signal velocity

Impact of the turbulence wavenumber spectrum and probing beam geometry on Doppler reflectometry perpendicular velocity measurements

The perpendicular propagation velocity of turbulent density fluctuations is an important parameter in fusion plasmas, since sheared plasma flows are crucial for reducing turbulence, and thus an essential input parameter for turbulent transport simulations. ...

IOP Publishing Ltd2023

Space-time wave packets with reduced divergence and tunable group velocity generated in free space after multi-mode fiber propagation

Tobias Kippenberg, Maxim Karpov, Hao Song, Xinzhou Su

Previously, space-time wave packets (STWPs) have been gen-erated in free space with reduced diffraction and a tunable group velocity by combining multiple frequency comb lines each carrying a single Bessel mode with a unique wave num-ber. It might be poten ...

Optica Publishing Group2023

An elastic rod in frictional contact with a rigid cylinder

Pedro Miguel Nunes Pereira de Almeida Reis, Paul Grandgeorge, Tomohiko Sano

We investigate the load transmission along an elastic rod of finite cross-section in contact with a rigid cylinder, as system often referred to as the generalized capstan problem. In the presence of friction, the idealized classic capstan equation predicts ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Attenuation of Lamb Modes and SH Waves near cut-off Frequencies

Soumya Yandrapalli, Victor Plessky

Near cut-off frequencies, the shear horizontal (SH) and Lamb modes in a platelet are created by a bulk acoustic wave bouncing up and down between the platelet sides in an almost vertical direction. The small inclination angle corresponds to slow drift of e ...

IEEE2020

Instability of a thin viscous film flowing under an inclined substrate: steady patterns

François Gallaire, Gioele Mariano Nicolò Balestra, Pier Giuseppe Ledda, Gaëtan Pierre Clément Lerisson

The flow of a thin film coating the underside of an inclined substrate is studied. We measure experimentally spatial growth rates and compare them to the linear stability analysis of a flat film modelled by the lubrication equation. When forced by a statio ...

Cambridge University Press2020

Particle transport at arbitrary timescales with Poisson-distributed collisions

Ambrogio Fasoli, Ivo Furno, Paolo Ricci, Marcelo Baquero Ruiz, Fabian Manke

We develop a model to investigate the time evolution of the mean location and variance of a random walker subject to Poisson-distributed collisions at constant rate. The collisions are instantaneous velocity changes where a new value of velocity is generat ...

2019

Force measurement of a gas-assisted atomization using an impulse probe

Farzad Vakili Farahani

The main objective of this study was to develop further insight into the mass flux characterization of an effervescent atomization. The spray is injected through an industrial effervescent nozzle, and is measured using a newly developed coupled PDPA + IS m ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Orthogonally polarized frequency comb generation from a Kerr comb via cross-phase modulation

Tobias Kippenberg, Maxim Karpov, Martin Hubert Peter Pfeiffer, Arne Kordts, Lin Zhang

We experimentally demonstrate that a single microresonator can emit two orthogonally polarized individually coherent combs: (i) a strong polarized soliton comb and (ii) an orthogonally polarized continuous wave seeded weaker comb, generated from the first ...

OPTICAL SOC AMER2019

Hydraulic Reconstruction of the 1818 Gietro Glacial Lake Outburst Flood

Christophe Ancey, Tomás Alfredo Trewhela Palacios, Eric Bardou, Martin Funk

In the spring of 1818, ice avalanches from the Gietro Glacier created an ice dam, which in turn formed a glacial lake in the Drance Valley (Canton of Valais, Switzerland). Today, its maximum volume is estimated to have been 25x10(6) m(3). Cantonal authorit ...

2019

Flow field in a reservoir subject to pumped-storage operation - in situ measurement and numerical modeling

Anton Schleiss, Giovanni De Cesare, Michael Müller

In pumped-storage reservoirs, turbulent kinetic energy input from plant operation can be considerably high. Flow velocities were measured by Acoustic Doppler Current Profilers near the intake/outlet structure to describe flow patterns induced by pumped-sto ...

2018

Generalized resolution matrix for neutron spin-echo three-axis spectrometers

Thomas Keller, Felix Groitl

This article describes the energy resolution of spin-echo three-axis spectrometers (SE-TASs) by a compact matrix formalism. SE-TASs allow one to measure the line widths of elementary excitations in crystals, such as phonons and magnons, with an energy reso ...

INT UNION CRYSTALLOGRAPHY2018

Isogeometric approximation of cardiac electrophysiology models on surfaces: An accuracy study with application to the human left atrium

Alfio Quarteroni, Luca Dede', Toni Mikael Lassila, Alessandro Samuele Patelli, Andrea Bartezzaghi

We consider Isogeometric Analysis in the framework of the Galerkin method for the spatial approximation of cardiac electrophysiology models defined on NURBS surfaces; specifically, we perform a numerical comparison between basis functions of degree p >= 1 ...

Elsevier2017

Velocity profiles of turbidity currents flowing over a flat bed

Anton Schleiss, Giovanni De Cesare, Sabine Chamoun

Turbidity currents are the main source of suspended sediment transport in reservoirs and thus one of the main causes of sedimentation. One of the techniques used to avoid reservoir sedimentation is through venting of turbidity currents. In the framework of ...

2016

Enhanced discriminability for nonbiological motion violating the two-thirds power law

Olaf Blanke, Roy Salomon, Nathan Quentin Faivre, Laurène Véronique Vuillaume

The two-thirds power law describes the relationship between velocity and curvature in human motor movements. Interestingly, this motor law also affects visual motion perception, in which stimuli moving according to the two-thirds power law are perceived to ...

Association for Research in Vision and Ophthalmology (ARVO)2016

Detection and reconstruction of large-scale coherent flow structures in gravel-bed rivers

Ulrich Lemmin, Mário Jorge Rodrigues Pereira Da Franca

Large-scale flow structures (LSFS) in the streamwise direction are important features of gravel-bed river flows, because they may contribute to sediment transport and gas exchange. In the present study, these structures are detected using Huang's empirical ...

Wiley-Blackwell2015

Low density polyethylene (LDPE) passive samplers for the investigation of PCB point sources in rivers

Luiz Felippe De Alencastro, Nicolas Estoppey, Julien Omlin, Adrien Schopfer

This study aims to provide a passive sampling approach which can be routinely used to investigate polychlorinated biphenyl (PCB) sources in rivers. The approach consists of deploying low density polyeth- ylene (LDPE) strips downstream and upstream of poten ...

Pergamon-Elsevier Science Ltd2015

Queue Profile Estimation in Congested Urban Networks with Probe Data

Nikolaos Geroliminis, Mohsen Ramezani Ghalenoei

Queues at signalized intersections are the main cause of traffic delays and travel time variability in urban networks. In this article, we propose a method to estimate queue profiles that are traffic shockwave polygons in the time-space plane describing th ...

2015

Effect of water velocity on the uptake of polychlorinated biphenyls (PCBs) by silicone rubber (SR) and low-density polyethylene (LDPE) passive samplers. An assessment of the efficiency of performance reference compounds (PRCs) in river-like flow conditions

Luiz Felippe De Alencastro, Nicolas Estoppey, Julien Omlin, Adrien Schopfer

One aim of this study is to determine the impact of water velocity on the uptake of indicator polychlorinated biphenyls (iPCBs) by silicone rubber (SR) and low-density polyethylene (LDPE) passive samplers. A second aim is to assess the efficiency of perfor ...

Elsevier Science Bv2014

Influence of snow cover properties on avalanche dynamics

Michael Lehning, Betty Sovilla, Walter Steinkogler

The destructive power of an avalanche depends, among other things, on the overall mass and the snow conditions in the avalanche path. So far, the knowledge on the effect of snow conditions on avalanche behavior is limited and largely qualitative. We invest ...

Elsevier Science Bv2014

Analysis of lock-exchange gravity currents over smooth and rough beds

Mário Jorge Rodrigues Pereira Da Franca, Claudia Adduce

Gravity currents produced by full-depth lock-release of saline water into a fresh water tank are studied focusing on the influence of the initial density of the saline mixture in the lock and the bed roughness on gravity current kinematics. Temporal evolut ...

Taylor & Francis Ltd2013