Publications associées à Fréquence fondamentale

Power performance of a model floating wind turbine subjected to cyclic pitch motion: A wind tunnel study

Fernando Porté Agel, Guiyue Duan, Daniele Gattari

Wind tunnel experiments were performed with a miniature floating wind turbine model to study the effects of cyclic pitch motion on its power performance. The cyclic pitch motion was prescribed by two key parameters: pitch frequency and amplitude. The power ...

IOPscience2024

Computationally Efficient Synchrophasor Estimation: Delayed In-Quadrature Interpolated DFT

Mario Paolone, Cesar Garcia Veloso

The paper proposes a synchropahsor estimation (SE) algorithm that leverages the use of a delayed in-quadrature complex signal to mitigate the self-interference of the fundamental tone. The estimator, which uses a three-point IpDFT combined with a three-cyc ...

2024

Dynamic behavior of exposed geomembrane systems in pressure waterways

Giovanni De Cesare, Samuel Luke Vorlet, Roberto Proença Seixas

Geomembrane systems have been used in dams and reservoirs as rehabilitation technology since several decades and are now used worldwide. They act as impervious layer to prevent and mitigate water leakage and damage to structures. They meet the needs of man ...

CRC Press/Balkema2023

Tunable photo-induced second-harmonic generation in a mode-engineered silicon nitride microresonator

Camille Sophie Brès, Jianqi Hu, Anton Stroganov, Boris Zabelich, Edgars Nitiss

All-optical poling enables reconfigurable and efficient quasi-phase-matching for second-order parametric frequency conversion in silicon nitride integrated photonics. Here, we report broadly tunable milliwatt-level second-harmonic generation in a small fre ...

2023

Nonlinear Frequency Conversion in III-Nitride Doubly Resonant Photonic Crystal Cavities

Jun Wang

Nonlinear frequency conversion processes, such as second-harmonic generation (SHG) and spontaneous parametric down-conversion (SPDC), are essential in many applications, including the generation of entangled photons. It's desirable to enhance these process ...

EPFL2023

A chip-scale second-harmonic source via self-injection-locked all-optical poling

Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Edgars Nitiss, Marco Clementi

Second-harmonic generation allows for coherently bridging distant regions of the optical spectrum, with applications ranging from laser technology to self-referencing of frequency combs. However, accessing the nonlinear response of a medium typically requi ...

2023

Dynamics of entrapped microbubbles with multiple openings

Mahmut Selman Sakar, Murat Kaynak, Amit Yedidia Dolev

Microbubbles excited by acoustic fields inside water oscillate, and generate acoustic radiation forces and drag-induced acoustic streaming. These forces can be harnessed in various biomedical applications such as targeted drug delivery and on-chip biomanip ...

2022

Experimental Study to Validate an Improved Approach to Design Acceleration-Sensitive Nonstructural Components

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Nonstructural components in buildings can be subjected to very large acceleration and deformation demands during earthquakes. This is particularly true for flexible components that are tuned or nearly tuned to one of the modal frequencies of the supporting ...

Applied Technology Council, Sponse2022

Isogeometric Kirchhoff-Love shell patches in free and forced vibration of sinusoidally corrugated FG carbon nanotube-reinforced composite panels

Anastasios Vassilopoulos

Application of the isogeometric method is illustrated for free and forced vibration analyzes of sinusoidally corrugated functionally graded carbon nanotube reinforced composite (FG-CNTRC) thin panels. These panels can be used as a potential structure for m ...

ELSEVIER SCI LTD2022

Hierarchical tensile structures with ultralow mechanical dissipation

Tobias Kippenberg, Sergey Fedorov, Alberto Beccari, Amirali Arabmoheghi, Nils Johan Engelsen

Structural hierarchy is found in myriad biological systems and has improved man-made structures ranging from the Eiffel tower to optical cavities. In mechanical resonators whose rigidity is provided by static tension, structural hierarchy can reduce the di ...

Nature Portfolio2022

Controlling the magnetic and electric responses of dielectric nanoparticles via near-field coupling

Olivier Martin, Andrei Kiselev

Among the two materials families used in nanophotonics, the fundamental mode for metal nanostructures is electric, while that for dielectric nanostructures is magnetic. Consequently, the optical properties of hybrid dimers that incorporate both materials h ...

2022

4-Port Microstrip planar resonator for multiband microwave material characterization applications

Anja Skrivervik, Sujith Raman

Planar microstrip resonators suitable for material characterization application are presented in this paper. The prototype consists of three resonators fed through four ports in a planar dielectric substrate without any additional resonators. The resonator ...

IEEE2022

Generation of OAM-carrying space-time wave packets with time-dependent beam radii using a coherent combination of multiple LG modes on multiple frequencies

Tobias Kippenberg, Maxim Karpov, Zhe Zhao, Hao Song, Xinzhou Su

Space-time (ST) wave packets, in which spatial and temporal characteristics are coupled, have gained attention due to their unique propagation characteristics, such as propagation invariance and tunable group velocity in addition to their potential ability ...

Optica Publishing Group2022

Seeded Multimode Quasi-Phase-Matching in All-Optically Poled Silicon Nitride Waveguides

Camille Sophie Brès, Ozan Yakar, Edgars Nitiss

We demonstrate seeding-enabled all-optical poling of silicon nitride waveguides as short as 5 mm, and account for quasi-phase-matching (QPM) inside the waveguide between the fundamental mode of pump and higher order second-harmonic modes. ...

OSA2021

Study on the Performances of AlScN based SAW/BAW Hybrid Resonators A Parametric Analysis of Acoustic Wave Resonators with Large Figure of Merit

Luis Guillermo Villanueva Torrijo, Soumya Yandrapalli, Guilain Lionel Germain Lang

In this study, we analyze a 3rd type of FBAR's fundamental mode by finite element method. We show the importance of the substrate's wave velocity and conductivity on the electromechanical coupling efficiency. Then we demonstrate that etching traditional SA ...

IEEE2021

Characterization of Real-World Power System Signals in Non-Stationary Conditions using a Dictionary Approach

Mario Paolone, Asja Derviskadic, Guglielmo Frigo, Alexandra Cameron Karpilow

As power grids transition towards low-inertia net-works based on converter-interfaced renewable energy resources, they become increasingly vulnerable to extreme dynamics. Currently, the most advanced methods for signal processing in power systems are embed ...

IEEE2021

The effect of low-frequency equalisation on preference and sensorimotor synchronisation in music

Steffen Alexander Herff

Equalisation, a signal processing technique commonly used to shape the sound of music, is defined as the adjustment of the energy in specific frequency components of a signal. In this work, we investigate the effects of equalisation on preference and senso ...

SAGE PUBLICATIONS LTD2021

Nonreciprocity in Uniform Time-Varying Materials Using Spatial Dispersion

Xiaoqiang Wang, Mohammad Sajjad Mirmoosa, Xiao Wang

Conventionally, nonreciprocity in time-varying systems is achieved by exploiting both temporal and spatial modulations. In this paper, we introduce a concept of magnetless bianisotropic time-modulated systems that support nonreciprocal wave propagation at ...

IEEE2020

Nonreciprocity in Bianisotropic Systems with Uniform Time Modulation

Xiaoqiang Wang, Mohammad Sajjad Mirmoosa, Xiao Wang

Physical systems with material properties modulated in time provide versatile routes for designing magnetless nonreciprocal devices. Traditionally, nonreciprocity in such systems is achieved exploiting both temporal and spatial modulations, which inevitabl ...

AMER PHYSICAL SOC2020

Fractal-like Mechanical Resonators with a Soft-Clamped Fundamental Mode

Tobias Kippenberg, Sergey Fedorov, Alberto Beccari, Nils Johan Engelsen

Self-similar structures occur naturally and have been employed to engineer exotic physical properties. We show that acoustic modes of a fractal-like system of tensioned strings can display increased mechanical quality factors due to the enhancement of diss ...

AMER PHYSICAL SOC2020