Read by QxMD icon Read

Journal of the Acoustical Society of America

Nansha Gao, Zhengyu Wei, Hong Hou, Anastasiia O Krushynska
This paper proposes a strategy to broaden complete bandgap attenuating flexural and longitudinal modes, and to shift them to lower frequencies by spatially folding designs. Numerical simulations show that the V-folded acoustic black hole beam exhibits an ultra-wide complete bandgap below 1 kHz due to longitudinal-flexural waveform transformation, and experimental results verify this finding. The proposed folded beams are easy-to-fabricate, of compact dimensions, and exhibit excellent wave attenuation functionality that makes them promising for low-frequency vibration reduction and wave attenuation applications...
January 2019: Journal of the Acoustical Society of America
Sinthiya Thavam, Mathias Dietz
It is well-established that the smallest discrimination thresholds for interaural time differences (ITDs) are near 10 μs for normal hearing listeners. However, little is known about the hearing and training status of the test subjects from past studies. Previous studies also did not explicitly focus on the identification of the optimal stimulus and measurement technique to obtain the smallest threshold ITDs. Therefore, the first goal of the current study was to identify the stimulus and experimental method that maximizes ITD sensitivity...
January 2019: Journal of the Acoustical Society of America
Mats E Nilsson, Carlos Tirado, Malina Szychowska
Listeners have limited access to spatial information in lagging sound, a phenomenon known as discrimination suppression. It is unclear whether discrimination suppression works differently for interaural time differences (ITDs) and interaural level differences (ILDs). To explore this, three listeners assessed the lateralization (left or right) and detection (present or not) of lag clicks with a large fixed ITD (350 μs) or ILD (10 dB) following a diotic lead click, with inter-click intervals (ICIs) of 0...
January 2019: Journal of the Acoustical Society of America
Zachary J Waters, Jason L Kost, Timothy J Yoder, Daniel L Amon, Michael L Saniga, Alain R Berdoz, Harry J Simpson, Brian H Houston, Paul J Gendron
The feasibility of resolving target returns within receive signals collected by a continuously transmitting quasi-monostatic, broadband, autonomous underwater vehicle (AUV) based sonar is explored. Theoretical studies supported by experimental results suggest that it is possible to capture the source-to-receiver coupling response and target scattering with sufficient fidelity during the continuous transmission to enable detection and (potentially) classification processing. Demonstrations focused upon the detection of a bottomed target object at sea using transmit signals with duty cycles of 60% and 100% indicate that such an approach is feasible for a representative AUV-based side looking sonar system operating in shallow water...
January 2019: Journal of the Acoustical Society of America
Michael L Kuntzman, Janice L LoPresti, Yu Du, Wade F Conklin, Vahid Naderyan, Sung B Lee, David Schafer, Michael Pedersen, Peter V Loeppert
No abstract text is available yet for this article.
January 2019: Journal of the Acoustical Society of America
Yuki Ueda, Naoyuki Ogura
The acoustic dissipation that occurs in a porous medium is experimentally investigated. Two conditions are tested. One is that the wall of the porous medium is wet by water, and the other is that it is dry. Experimental results show that water does not affect viscous dissipation; however, it affects the dissipation caused by pressure oscillation. Furthermore, it is found that the effect of water on the dissipation due to pressure oscillation increases with the temperature of the working gas. A theory that can consider the effect of condensation and evaporation on sound propagation is used to investigate the result...
January 2019: Journal of the Acoustical Society of America
Maria M Karzova, Thomas Lechat, Sébastien Ollivier, Didier Dragna, Petr V Yuldashev, Vera A Khokhlova, Philippe Blanc-Benon
The irregular reflection of weak acoustic shock waves, known as the von Neumann reflection, has been observed experimentally and numerically for spherically diverging waves generated by an electric spark source. Two optical measurement methods are used: a Mach-Zehnder interferometer for measuring pressure waveforms and a Schlieren system for visualizing shock fronts. Pressure waveforms are reconstructed from the light phase difference measured by the interferometer using the inverse Abel transform. In numerical simulations, the axisymmetric Euler equations are solved using finite-difference time-domain methods and the spark source is modeled as an instantaneous energy injection with a Gaussian shape...
January 2019: Journal of the Acoustical Society of America
Manuel C Kohl, Erik Schebsdat, Elena N Schneider, Annika Niehl, Daniel J Strauss, Özcan Özdamar, Jorge Bohórquez
This work relates to recent advances in the field of auditory event-related potentials (ERP), specifically deconvolution-based ERP acquisition and single-trial processing. An efficient stimulus sequence optimization method for ERP deconvolution is proposed, achieving consistent noise attenuation within a broad designated frequency range. Furthermore, a stimulus presentation paradigm for the fast, interleaved acquisition of auditory brainstem, middle-latency and late responses featuring alternating periods of high-rate deconvolution sequences, and subsequent low-rate stimulation is investigated in 20 normal hearing subjects...
January 2019: Journal of the Acoustical Society of America
Jing Han, Yujie Wang, Lingling Zhang, Geert Leus
Orthogonal signal-division multiplexing (OSDM) is a recently emerging modulation scheme which, compared to conventional orthogonal frequency-division multiplexing, can effectively lower the peak-to-average power ratio and introduce intra-vector frequency diversity. In this paper, a time-domain oversampled OSDM system for underwater acoustic (UWA) communications is designed, where each OSDM vector is equivalently transmitted over multiple virtual channels, and thus an enhanced frequency diversity gain can be achieved...
January 2019: Journal of the Acoustical Society of America
Christophe Droz, Olivier Robin, Mohamed Ichchou, Noureddine Atalla
An important dip in the sound transmission loss of curved panels occurs at the ring frequency. The relevance of using small-scale resonators to solve this issue is experimentally demonstrated on an aircraft sidewall panel. The effect of varying the spatial distribution of single frequency resonators (including combination with a broadband soundproofing treatment), as well as using multi-frequency resonators with a fixed spatial distribution is studied. Large improvement of the measured sound transmission loss under a diffuse acoustic field excitation is obtained around the ring frequency with limited added mass and very small alteration of the overall sound insulation performance...
January 2019: Journal of the Acoustical Society of America
Byeongho Jo, Jung-Woo Choi
The eigenbeam estimation of signal parameters via the rotational invariance technique (EB-ESPRIT) is a well-known subspace-based beamforming algorithm for a spherical microphone array. EB-ESPRIT uses a recurrence relation to directly estimate directional parameters expressing directions-of-arrival (DOAs) of sound sources without an exhaustive grid-search. In the conventional EB-ESPRIT, the directional parameter along the elevational direction is given by a tangent function, which inevitably produces two shortcomings...
January 2019: Journal of the Acoustical Society of America
Peter Harris, Kostas Sotirakopoulos, Stephen Robinson, Lian Wang, Valerie Livina
Deep ocean ambient sound levels have been the subject of recent studies, with particular interest in the identification of long term trends. This paper describes a statistical method for performing long term trend analysis and uncertainty evaluation of the estimated trends. Uncertainties are needed if the quality of the estimates are to be assessed and if the results from different studies or different methods are to be compared. The measured data span 14 years, from 2003 to 2017, and originate from the Southern Ocean close to Cape Leeuwin, Australia...
January 2019: Journal of the Acoustical Society of America
Junjian Zhang, Zhongquan Charlie Zheng, Guoyi Ke
Simulations of ultrasound wave propagation inside biological tissues have a wide range of practical applications. In previous studies, wave propagation equations in lossy biological media are solved either with convolutions, which consume a large amount of memory, or with pseudo-spectral methods, which cannot handle complicated geometries effectively. The approach described in the paper employed a fractional central difference method (FCD), combined with the immersed boundary (IB) method for the finite-difference, time-domain simulation...
January 2019: Journal of the Acoustical Society of America
Shudong Yu, Xuewen Yin
A generalized superposition method is presented in this paper for free bending vibration analysis of single rectangular plates and assemblies of rectangular plates with arbitrary boundary conditions. The method was developed on the basis of the Levy method, the principle of superposition, and the uniform convergence of half-range Fourier cosine series for continuous functions in a closed interval. Numerical results, obtained using the proposed method for thin isotropic plates and plate assemblies, show that the proposed method is accurate and rapidly convergent...
January 2019: Journal of the Acoustical Society of America
Michael Smotherman, Kushal Bakshi
Forward masking is a widespread auditory phenomenon in which the response to one sound transiently reduces the response to a succeeding sound. This study used auditory brainstem responses to measure temporal masking effects in the free-tailed bat, Tadarida brasiliensis. A digital subtraction protocol was used to isolate responses to the second of a pair of pulses varying in interval, revealing a suppression phase lasting <4 ms followed by an enhancement phase lasting 4-15 ms during which the ABR waveform was amplified up to 100%...
January 2019: Journal of the Acoustical Society of America
Martina Guidetti, Thomas J Royston
A theoretical approach was recently introduced by Guidetti and Royston [J. Acoust. Soc. Am. 144, 2312-2323 (2018)] for the radially converging elliptic shear wave pattern in transverse isotropic materials subjected to axisymmetric excitation normal to the fiber axis at the outer boundary of the material. This approach is enabled via a transformation to an elliptic coordinate system with isotropic properties. The approach is extended to the case of diverging shear waves radiating from a cylindrical rod that is axially oscillating perpendicular to the axis of isotropy and parallel to the plane of isotropy...
January 2019: Journal of the Acoustical Society of America
Daniel Pereira, Guillaume Haïat, Julio Fernandes, Pierre Belanger
The assessment of intracortical bone properties is of interest since early-stage osteoporosis is associated with resorption in the endosteal region. However, understanding the interaction between ultrasonic guided waves and the cortical bone structure remains challenging. The purpose of this work is to investigate the effect of intracortical bone properties on the ultrasonic response obtained at low-frequency (<100 kHz) using an axial transmission configuration. The semi-analytical finite element method was used to simulate the propagation of guided waves in a waveguide with realistic geometry and material properties...
January 2019: Journal of the Acoustical Society of America
Felipe Pires, Stéphane Avril, Steve Vanlanduit, Joris Dirckx
Structural intensity on plates or shells can provide insights on how the vibrational energy is transmitted throughout a sample. Its assessment via experimental deflections are widely documented in the case of plates, which just requires the computation of spatial derivatives of out-of-plane displacements or velocities and a knowledge of the sample's material properties. However, if the structural intensity is to be assessed on arbitrary shells, a more elaborate data processing is required. The in-plane displacements become relevant terms and the spatial derivatives along a predefined local coordinate system need to be computed...
January 2019: Journal of the Acoustical Society of America
Seki Inoue, Shinichi Mogami, Tomohiro Ichiyama, Akihito Noda, Yasutoshi Makino, Hiroyuki Shinoda
In previous studies, acoustical levitation in the far-field was limited to particles. Here, this paper proposes the "boundary hologram method," a numerical design technique to generate a static and stable levitation field for macroscopic non-spherical rigid bodies larger than the sound wavelength λ. This paper employs boundary element formulation to approximate the acoustic radiation force and torque applied to a rigid body by discretizing the body surface, which is an explicit function of the transducer's phase and amplitude...
January 2019: Journal of the Acoustical Society of America
Adam R Fishbein, Shelby L Lawson, Robert J Dooling, Gregory F Ball
The melodic, rolling songs of canaries have entertained humans for centuries and have been studied for decades by researchers interested in vocal learning, but relatively little is known about how the birds listen to their songs. Here, it is investigated how discriminable the general acoustic features of conspecific songs are to canaries, and their discrimination abilities are compared with a small parrot species, the budgerigar. Past experiments have shown that female canaries are more sexually responsive to a particular song element-the "special" syllables-and consistent with those observations, it was found that special syllables are perceptually distinctive for canaries...
January 2019: Journal of the Acoustical Society of America
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"