In the stress-energy tensor formalism, the symmetry between absorption and scattering coefficients, as proven by measurements combined with simulations, is counterintuitive. By introducing the wall admittance, we show that the scattering coefficient is partly created by the real part of the wall admittance combined with the active intensity, that is, is partly due to absorption. However, for curved surfaces or finite source distances, it also depends on the imaginary part of the wall admittance in combination with the reactive intensity, which confers its genuine scattering properties inversely proportional to the distances to the sources. Thus, for plane waves impinging on plane boundaries, or purely real admittances, scattering reduces to absorption.
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http://dx.doi.org/10.1121/10.0025468 | DOI Listing |
Ear Hear
October 2024
Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, Knoxville, Tennessee, USA.
Objectives: The first objective of the study was to compare approaches to eardrum electrode insertion as they relate to the likelihood of introducing an acoustic leak between the ear canal and eartip. A common method for placing a tympanic membrane electrode involves securing the electrode in the canal by routing it underneath a foam eartip. This method is hypothesized to result in a slit leak between the canal and foam tip due to the added bulk of the electrode wire.
View Article and Find Full Text PDFJ Acoust Soc Am
April 2024
LTCI, Télécom Paris, F-91120 Palaiseau, France.
In the stress-energy tensor formalism, the symmetry between absorption and scattering coefficients, as proven by measurements combined with simulations, is counterintuitive. By introducing the wall admittance, we show that the scattering coefficient is partly created by the real part of the wall admittance combined with the active intensity, that is, is partly due to absorption. However, for curved surfaces or finite source distances, it also depends on the imaginary part of the wall admittance in combination with the reactive intensity, which confers its genuine scattering properties inversely proportional to the distances to the sources.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2024
Laboratory of Ocean Acoustic Technology, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China.
The Janus-Helmholtz (JH) transducer is a low-frequency, high-power, broadband underwater transducer type. Numerous studies have shown the effectiveness of the finite element method (FEM) in designing JH transducers and predicting their electroacoustic performance. However, a precise theoretical model for JH transducers has not yet been proposed, and the modal identification problem of JH transducers remains unsolved.
View Article and Find Full Text PDFInt J Comput Assist Radiol Surg
February 2024
Institute of Forming Technology and Equipment, Shanghai Jiao Tong University, Shanghai, 200240, China.
Purpose: The development of cardiovascular interventional surgery robots can realize master-slave interventional operations, which will effectively solve the problem of surgeons being injured by X-ray radiation. The delivery accuracy and safety of interventional instruments such as guidewire are the most important issues in the development of robotic systems. Most of the current control methods are position control or force feedback control, which cannot take into account delivery accuracy and safety.
View Article and Find Full Text PDFExp Physiol
September 2022
Department of Anaesthesia, Rigshospitalet, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
New Findings: What is the central question in this study? Atrial natriuretic peptide (ANP) is secreted in response to atrial wall distension and thus allows for evaluation, albeit indirect, of the central blood volume. Adrenaline has chronotropic and inotropic effects. We evaluated whether the chronotropic and inotropic effects of adrenaline were reflected in mid-regional proANP.
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