This paper evaluates the performance of various regularization parameter choice methods applied to different approaches of nearfield acoustic holography when a very nearfield measurement is not possible. For a fixed grid resolution, the larger the hologram distance, the larger the error in the naive nearfield acoustic holography reconstructions. These errors can be smoothed out by using an appropriate order of regularization. This study shows that by using a fixed/manual choice of regularization parameter, instead of automated parameter choice methods, reasonably accurate reconstructions can be obtained even when the hologram distance is 16 times larger than the grid resolution.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1121/1.4954757 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Porous ground treatments for propeller noise reduction in ground effect.
Sci Rep
January 2025
Department of Aerospace Engineering, University of Bristol, Bristol, BS8 1TR, UK.
This study investigates the aerodynamic and aeroacoustic behavior of propellers operating in ground-effect conditions, with an emphasis on the impact of porous ground surface treatments. The investigation explores the potential of porous materials to reduce propeller noise near the ground, a major barrier to the acceptance and integration of Urban Air Mobility (UAM) systems. Experiments were conducted in an anechoic chamber using an APC [Formula: see text] inch propeller in a pusher configuration.
View Article and Find Full Text PDFNew Torsional Surface Elastic Waves in Cylindrical Metamaterial Waveguides for Sensing Applications.
Sensors (Basel)
December 2024
Institute of Fundamental Technological Research, Polish Academy of Sciences, ul. Pawińskiego 5B, 02-106 Warsaw, Poland.
In this paper, we demonstrate that torsional surface elastic waves can propagate along the curved surface of a metamaterial elastic rod (cylinder) embedded in a conventional elastic medium. The crucial parameter of the metamaterial rod is its elastic compliance s44(1)ω, which varies as a function of frequency ω analogously to the dielectric function εω in Drude's model of metals. As a consequence, the elastic compliance s44(1)ω can take negative values s44(1)ω<0 as a function of frequency ω.
View Article and Find Full Text PDFTransformation-Invariant Laplacian Metadevices Robust to Environmental Variation.
Adv Mater
January 2025
National Key Laboratory of Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China.
As one of the typical applications of metamaterials, the invisibility cloak has raised vast research interests. After many years' research efforts, the invisibility cloak has extended its applicability from optics and acoustics to electrostatics and thermal diffusion. One scientific challenge that has significantly restricted the practical application of the invisibility cloak is the strong background dependence, that is, all passive cloaking devices realized thus far are unable to resist variation in the background refractive index.
View Article and Find Full Text PDFNear-field acoustic imaging with a caged bubble.
Nat Commun
November 2024
Univ. Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France.
Article Synopsis
- - Bubbles are vital in various fields, such as ultrasound imaging and studying natural phenomena like volcanic eruptions, due to their unique acoustic properties as resonant scatterers.
- - Researchers have developed a method to confine a cubic bubble using 3D printing, allowing them to study its interactions with the surrounding environment at a single-bubble level.
- - This new technique enables near-field acoustic imaging with much higher resolution than traditional methods, potentially leading to the creation of affordable acoustic microscopes using these caged bubbles.
Soft-lithographically defined template for arbitrarily patterned acoustic bioassembly.
Biofabrication
December 2024
Tissue Engineering and Organ Manufacturing (TEOM) Lab, Department of Biomedical Engineering, TaiKang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan, Hubei 430071, People's Republic of China.
Acoustic bioassembly is recently regarded as a highly efficient biofabrication tool to generate functional tissue mimics. Despite their capacity of directly patterning live cells with close intercellular proximity, most acoustic bioassembly techniques are currently limited to generate some specific simple types of periodic and symmetric patterns, which represents an urgent challenge to emulate geometrically complex cytoarchitecture in human tissue. To address this challenge, we herein demonstrate a soft-lithographically defined acoustic bioassembly (SLAB) technique that enables to assemble live cells into geometrically defined arbitrary multicellular structures.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!