Rotation of an elastic medium gives rise to a shift of frequency of its acoustic modes, i.e., the time-period vibrations that exist in it. This frequency shift is investigated by applying perturbation theory in the regime of small ratios of the rotation velocity and the frequency of the acoustic mode. In an expansion of the relative frequency shift in powers of this ratio, upper bounds are derived for the first-order and the second-order terms. The derivation of the theoretical upper bounds of the first-order term is presented for linear vibration modes as well as for stable nonlinear vibrations with periodic time dependence that can be represented by a Fourier series.
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http://dx.doi.org/10.1121/1.3693646 | DOI Listing |
Hear Res
March 2025
Hearing Systems Section, Department of Health Technology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
Acoustic amplitude modulation (AM) patterns carry important information, particularly in speech. AM masking, influenced by frequency selectivity in the modulation domain, is considered a crucial factor for speech intelligibility in noisy environments. Based on recent evidence suggesting an age-related decline in AM frequency selectivity, this study investigated whether increased AM masking in older listeners is associated with reduced speech intelligibility.
View Article and Find Full Text PDFThe interaction between surface acoustic waves (SAWs) and magnons is an interesting phenomenon that can be used to control spins in spintronic devices, and thus the visualization of the related spatiotemporal dynamics can be useful. In this study, we used dual-frequency-comb-based asynchronous optical sampling to record the spatiotemporal evolution of the surface vibration associated with an optically excited SAW and that of the spin precession associated with the magnon under the same excitation condition at effectively 160 frames/ns. Isotropic and anisotropic propagation were observed for phonons and magnons, respectively, demonstrating the capability of measuring such dynamics with high resolution.
View Article and Find Full Text PDFAlzheimers Dement
February 2025
Department of Medicine, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts, USA.
Introduction: Digital voice analysis is an emerging tool for differentiating cognitive states, but it poses privacy risks as automated systems may inadvertently identify speakers.
Methods: We developed a computational framework to evaluate the trade-off between voice obfuscation and cognitive assessment accuracy, using pitch-shifting as a representative method. This framework was applied to voice recordings from the Framingham Heart Study (FHS, n = 128) and the DementiaBank Delaware (DBD, n = 85) corpus, both featuring responses to neuropsychological tests.
J Speech Lang Hear Res
March 2025
Graduate Program for Neuroscience, Boston University, MA.
Purpose: Cognitive load and autonomic arousal are hypothesized to affect voice production, yet the nature of these relationships is unclear. The purpose of this study was to assess how cognitive load and autonomic arousal differentially affect voice production and vocal motor control.
Method: Physiological measures of autonomic arousal were recorded from 30 adults under different cognitive loads elicited by a Stroop task.
J Acoust Soc Am
March 2025
Department of Medical Physics and Biomedical Engineering, University College London, London, WC1E 6BT, United Kingdom.
We describe and implement a numerical method for modelling the frequency-dependent power-law absorption of ultrasound in tissue, as governed by the first order linear wave equations with a loss taking the form of a fractional time derivative. The (Caputo) fractional time derivative requires the full problem history, which is contained within an iterative procedure. The resulting numerical method requires a fixed (static) memory cost, irrespective of the number of time steps.
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