摘要:

The presence of continuous, narrow‐band acoustic signals (oto‐acoustic emissions) in recordings made from the ear canals of human subjects has been reported by several authors. We report here the results of our attempt to detect such emissions from a series of 92 normally hearing ears from 47 adult subjects. Our results were quite similar to those reported by Zurek [J. Acoust. Soc. Am.69, 514–523 (1981)]. Emissions were found in 38% of the people and 27% of the ears tested. The distributions of the recorded emissions were also very similar to the results of Zurek’s study.

ISSN:0001-4966    

DOI:10.1121/1.391376

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

摘要:

An analysis of the effectiveness of a constrained layer damping treatment for in‐plane vibrations of a plate is presented. The loss factor is shown to be that of an unconstrained layer treatment for frequencies below a cutoff frequency and to be substantially larger above this frequency.

ISSN:0001-4966    

DOI:10.1121/1.391377

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

摘要:

The propagation of Rayleigh waves on a convex cylindrical poroelastic surface is studied for pervious and impervious surfaces. A plot relating the nondimensional phase velocity with the angular wavenumber is presented. The results for a plane surface and a purely elastic solid are studied as particular cases.

ISSN:0001-4966    

DOI:10.1121/1.391378

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

摘要:

A new canonical sound velocity profile is presented in which the velocity cubed varies linearly with depth and is characterized by two parameters. The ray acoustic equations have exact analytic solutions for this profile, and the expressions for horizontal range, travel time, and intensity are derived. It is shown that the canonical profile can be derived approximately from Hamilton’s profile for bottom sediments obtained from sonobuoy data. The agreement between the two is shown to be excellent for both the velocity and the velocity gradient even for sediment thicknesses of 1 km.

ISSN:0001-4966    

DOI:10.1121/1.391379

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

摘要:

Readers of the subject paper might conclude that Haran and Cook are the first to derive an alogorithm based on Burgers’ equation which calculates the nonlinear propagation of a plane wave in a lossy medium with nonquadratic frequency‐dependent absorption coefficients. In fact, we presented such an algorithm in an earlier paper [D. H. Trivett and A. L. Van Buren, ‘‘Propagation of plane, cylindrical, and spherical finite amplitude waves,’’ J. Acoust. Soc. Am.69, 943–949 (1981)] and we feel that the Haran and Cook’s reference to our work was insufficient. Although the derivation given by Haran and Cook is correct, it contains an inconsistency in notation. Also, their numerical results for propagation in fresh water correspond to different initial conditions than stated in the paper.

ISSN:0001-4966    

DOI:10.1121/1.391380

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

摘要:

A simplified theoretical model based upon phonon diffusion is proposed in this paper for the evaluation of the intensity level of ultrasonic waves in inhomogeneous media. This model shows large similarities with well‐known energy transfer theories and leads to particularly simple analytical results applicable to the case where the incoherent wave level predominates over the coherent one. A characteristic length beyond which acoustic image reconstruction is no longer feasible is defined here and a very simple analytical formula for this important parameter is derived. This model is then applied to the acoustic wave propagation in concrete. A reasonable fit is found between theory and experiments in this case.

ISSN:0001-4966    

DOI:10.1121/1.391381

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.391646

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.391382

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.391384

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.391388

出版商:Acoustical Society of America    

年代:1984

数据来源: AIP