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The Reflections series takes a look back on historical articles from The Journal of the Acoustical Society of America that have had a significant impact on the science and practice of acoustics.

Sonoluminescence is the production of electromagnetic radiation, much of it in the form of visible light, that is emitted from a gas-filled cavity that has grown and collapsed under the influence of a varying pressure field. This resource paper provides a guide to the literature of sonoluminescence, from its early history to the present.

The earliest comprehensive, in-situ measurements of the acoustic backscattering strength of the seabed as a function of frequency, grazing angle and sediment type were made by McKinney and Anderson, and published in the society’s journal in 1964. It was a landmark paper and laid the groundwork for subsequent measurements and models. It is widely referenced in books and papers where seabed scattering and sonar performance prediction are concerned. Scattering strength and sediment classification, usually quantified in terms of the mean grain diameter, were thought to be closely connected. In the laboratory, using pristine samples of sorted sand, this connection was clearly demonstrated, but in situ it was overwhelmed by other factors, such as uneven size distributions, biological activity and roughness. The underlying nature of the seabed is also reflected in the scattering strength. For the same roughness, density and sound speed, the solid/fluid model consistently overestimates the scattering strength bec...

The quality of a waste paper bale depends heavily on its moisture content. The higher the moisture content, the lower the quality as a recycled resource. Therefore, accurate measurement of the moisture content of a waste paper bale is a pressing concern in the paper recycling industry. In this paper, a theoretical model for a waste paper bale, an exotic and complex medium, is developed, in which the acoustic properties of the bale are assumed to be functions of the moisture content. The model is validated through a series of impact resonance tests, which show a strong correlation between the moisture content, resonance frequencies, and the associated quality factors.

Experiments with laser generation and detection of ultrasound in copy paper indicate that earliest arrivals of ultrasound are antisymmetric. A likely explanation is that the out-of-plane interferometer is relatively insensitive to the symmetric compressional pulse because of the low Poisson ratio of copy paper, but rather sensitive to its antisymmetric flexural wake associated with the random heterogeneities and gradients present in copy paper.

A composition and process suitable for making acoustic tiles are disclosed. Certain embodiments of the composition comprise: perlite; inorganic material selected from the group consisting of calcium sulfate, calcium carbonate, clay and mixtures thereof; a binder selected from the group consisting of starch, a combination of starch and cellulosic fibers, latex, kraft paper gel and mixtures thereof; optionally mineral wool; optionally gypsum; and cellulosic fiber, wherein at least a portion of the cellulosic fiber and at least a portion of the inorganic material are pulp and paper processing waste comprising cellulosic fiber, clay and calcium carbonate. Certain embodiments of the process comprise: forming an aqueous slurry; continuously flowing slurry onto a moving foraminous wire to form a cake; dewatering the cake to form a base mat; and drying the base mat.

In this paper, a new method of measuring Young’s modulus in a paper cone is presented. The characteristics of this method are as follows. (1) The distribution of Young’s modulus along generatrix of the cone can be measured. (2) The technology of laser modulation is applied in this method. As a consequence, the setup of measurement has no influence on the vibration behavior. This new method has been tested and verified.

Paper-based microfluidics have recently become a topic of interest due to the ease and low expense in fabrication, especially compared to traditional microfluidics fabrication materials, making them suitable for inexpensive diagnostics. We report a convective actuation mechanism in a simple paper-based microfluidic device using surface acoustic waves to drive mixing. Using a Y-channel structure patterned onto paper, the mixing induced by 30 MHz acoustic waves is shown to be consistent and rapid, overcoming several limitations associated with its capillary-driven passive mixing counterpart: the latter exhibits nonuniform and irreproducible mixing. Capillary-driven mixing offers only poor control, is strongly dependent on the paper's texture and fibre alignment, and permits backflow, all due to the scale of the fibres being significant in comparison to the microfluidics features. Using a novel hue-based colourimetric technique, the mixing speed and efficiency is computed. For the acoustically driven mixing ...

The notebooks of Wallace Clement Sabine were discovered in 1975, and his consulting files were discovered in 1979. Both findings were reported [J. Acoust. Soc. Am. 61, 629–639 (1977); J. Acoust. Soc. Am. 69, 1–7 (1981)]. By chance, his personal papers were discovered recently and highlights from them are presented here with emphasis on his European activities from 1906 to 1917.

A method for measuring the rigidity of paper or other products made from cellulose fibers wherein the paper is torn and a digitized sound recording is made during the tearing process which is then analyzed to determine the percentage of time during which characteristic frequencies are present during the tearing process. It has been found that this percentage correlates well with rigidity.

A through‐transmission, dry‐contact ultrasonic technique aimed at investigating sound propagation in the thickness direction of paper materials is presented. The method uses piezoelectric ceramic transducers immersed in fluid‐filled rubber wheels. Thickness and longitudinal velocity are determined from time domain measurements for several commercial paper specimens between 40 and 1750 μm. Dispersion and attenuation are reported at frequencies up to 1.5 MHz. Dispersion is less than 10% between 0.25 and 1.25 MHz. Amplitude calculations are used to evaluate the attenuation coefficient versus the frequency. Using a nearly local form of the Kramers–Kronig relationships, the attenuation coefficient is also obtained from the phase information. By comparing the amplitude‐ and phase‐determined attenuation coefficients, an apparent reflection coefficient is predicted. It is shown that the Kramers–Kronig relationships can be applied to papers thicker than 200 μm under dry coupling conditions. The attenuation coeffic...

Echolocation (i.e., perceiving objects using acoustic echoes) is well-known in underwater detection and to a lesser extent in robot guidance and machine perception. The paper by Tsakiris and McKerrow is concerned with machine perception in air using Freedman's asymptotic model, which was originally developed to predict the backscattering multiple-echo effect observed in sonar detection. This effect was subsequently shown to be due to the elastic response of underwater targets. Freedman's model can be used in air because the acoustic target is assumed to be rigid. Also, the model's prediction of multiple echoes can be used to obtain information about the shape of the target. This is the so-called inversion of the Freedman model by Tsakiris and McKerrow. In their paper, various simple bodies are tested in air using ultrasound and it is shown that the model provides relatively poor information about body shape. Several explanations are given. However, one explanation is not considered, namely that the model itself is not satisfactory. First, there is poor agreement with exact backscattering theory. Second, deriving information about target shape from the multiple echoes predicted by the model is a highly questionable procedure. Both these aspects are examined here.

The following group of papers resulted from a special session entitled Speech Recognition and Perception from an Articulatory Point of View that was held during the spring 1994 meeting of the Acoustical Society of America in Cambridge, Massachusetts. Organization of the session began when Richard McGowan, Terry Nearey, and Juergen Schroeter invited speakers to give papers and critiques on the role of articulation in human perception and machine recognition. Presentations were invited from three speakers or groups of speakers who were representative of the three speech areas in the Society: production, perception, and processing. One talk was given by Bjorn Lindblom, another was given by John Ohala, and the third by Rick Rose, Juergen Schroeter, Mohan Sondhi, and Oded Ghitza. The invited critiquers for the Lindblom paper were Ken Stevens, Robert Remez, and Bishnu Atal; for the Rose et al. paper, Roger Moore, Joe Perkell, and Terry Nearey; and for the Ohala paper, Mary Beckman, Douglas O’Shaughnessy, and Carol Fowler. These people created a very interesting and provocative session. Robert Fox, associate editor of the speech perception section of the Journal, initiated publication of and edited the papers that appear here. Written versions of the invited papers are included here, as well as the critiques by Stevens, Remez, Nearey, Moore, and O’Shaughnessy. Because it was felt that Carol Fowler’s view of the importance of articulation in speech perception was not sufficiently aired in a short critique, she was asked to present her views in a longer paper.

Dose–response relationships of the sort pioneered by Schultz figure prominently in the current European noise regulation policy. A position paper developed by the Working Group on Dose‐effects (part of the EU Expert Network) reviewed a range of potential health effects, but decided that annoyance and sleep disturbance remain the most prevalent and sensitive effects of transportation noise exposure, and those for which the best data were available. A Position paper providing guidance on the dose–effect relations to be used for the assessment of numbers of people annoyed by noise from transportation sources (rail, road and air) may be found at http://europa.eu.int/comm/environment/noise/home.htm This presentation explains the context in which the Paper was developed, outlines the process by which the dose–response relationships were derived and summarizes the key recommendations. Finally some observations are made as the Position Paper is being applied, and related future developments are discussed. The author acknowledges with deep gratitude the assistance of Dr. Henk Miedema of TNO in preparing this paper.

Acoustic transmissions from a low‐frequency source near Heard Island in the southern Indian Ocean were monitored at 16 sites worldwide. The results are presented in the following papers. A summary is presented of what has been learned about the dimensions of this new subject: global acoustics.

Authors contemplating submitting papers to the Journal of the Acoustical Society of America (JASA) should first determine whether JASA is an appropriate journal, as it is possible that submissions for which this is not the case will be immediately rejected. A principal criterion is whether the paper will find a wider readership with JASA publication than with an alternative journal. If the appropriateness for JASA may not be manifestly obvious to the editors, then the authors should submit a cover letter explaining why, and they should write their paper so that there is a clear tie-in with articles previously published in JASA, preferably recent articles. Authors are advised to select the Associate Editor who is most likely to be familiar with the subject matter of the paper. Given that the paper is appropriate and an Associate Editor can be identified who is willing to handle the paper, it will be subsequently judged for possible acceptance based on several criteria: the most important being whether the paper is (i) original, (ii) significant, (iii) clearly written, and (iv) suitably limited in scope. The significance criterion is discussed at some length. The talk is illustrated by several disguised examples of recent submissions which were rejected.

A method for reducing the radiation amplitude of material vibration modes (division vibrations) from a loudspeaker transducer diaphragm mechanically vibrated for the purpose of transforming an electrical signal into an acoustic signal. The diaphragm material may consist of formed paper or plastic sheet materials or molded paper pulp. The amplitude reduction of material vibration modes and pressure waves within the diaphragm material is accomplished by impressing small, shaped structures within the diaphragm material at critical locations determined by measurement with laser vibration analysis or position sensitive transient analysis of a loudspeaker transducer. The method is applied to the diaphragm material after it has been formed into the shape of a loudspeaker transducer diaphragm, either before or after the diaphragm has been assembled into a loudspeaker transducer.

This article reviews Collected Papers in Building Acoustics: Room Acoustics and Environmental Noise by Barry Gibbs, John Goodchild, Carl Hopkins, David Oldham , 2010. 419 pp. Price: $115.00. ISBN: 978-1-907132-14-8

A Paper on the Theory of Sound.- On a Difficulty in the Theory of Sound.- On the Mathematical Theory of Sound.- The Propagation of Planar Air Waves of Finite Amplitude.- On the Thermodynamic Theory of Waves of Finite Longitudinal Disturbance.- The Life and Work of Pierre Henri Hugoniot.- On the Propagation of Motion in Bodies and in Perfect Gases in Particular -I.- On the Propagation of Motion in Bodies and in Perfect Gases in Particular - II.- Aerial Plane Waves of Finite Amplitude.- The Conditions Necessary for Discontinuous Motion in Gases.- On the Theory of Shock Waves for an Arbitrary Equation of State.- Shock Waves in Arbitrary Fluids.

A device for reducing vibrations and noises of a paper shredder uses a buffer device comprised of a rubber cylinder and a spring between core fixing frames and the housing base of the paper shredder. The buffer device is fixed by using screw and washer, enhancing the vibration and noise reduction effect for the paper shredder.

This article reviews 9th International Symposium on Therapeutic Ultrasound (ISTU 2009) by Kullervo Hynynen, Jacques Souquet , Melville, New York, 2010. 408 pp. Price: $224 (paper). ISBN: 978-0-7354-0758-9

There are now hundreds of patents and papers on synthetic aperture sonar; some of them of key importance whereas many others are of peripheral or minor interest. Here we take what we consider to be the top ten publications in synthetic aperture sonar and explain why we believe they are important and how they have made a significant contribution to the developing discipline or have made some leap of imagination in the area. This paper is more than a catalogue of the top ten citations since not all the real advances in the field have been published in academic peer‐review journals.

Russell Johnson was one of the most active acoustical consultants involved with concert hall design. He was a Senior Consultant at Bolt Beranek and Newman in Cambridge before he founded Artec. Sabine’s interactions with Mr. Johnson will be featured. In 1975, the notebooks of Wallace Clement Sabine were discovered and in 1979 his consulting files were discovered. Both findings were reported [J. Acoust. Soc. Am. 61, 629–639 (1977); J. Acoust. Soc. Am. 69, 1–6 (1981)]. By chance, Sabine’s personal papers were discovered recently and highlights from them will be presented with emphasis on his European activities from 1906 to 1917.

This paper points out a critical issue in the study of estimating the azimuth of ground sources by using the polarization characteristics of Rayleigh waves: even if the signal quality is good, the degree of polarization of Rayleigh waves varies across different frequency bands, and the band with the strongest energy is not the one with the lowest azimuth error. A direction of arrival estimation method for ground sources based on optimally polarized Rayleigh waves using a single three-component geophone is presented in this paper. First, the reciprocal ellipse rate, flatness coefficient, and the angle between the semi-minor axes and the horizontal plane are selected as the polarization parameters of this method according to two quantitative principles. Then the frequency band range of the optimal polarization Rayleigh wave is determined by analyzing the sum of the weights of the three polarization parameters in different frequency bands. After filtering and combining with the existing surface wave analysis method, the actual data bearing estimation result with an average error of only 4.95 degrees and a standard deviation of only 1.82 degrees is obtained. It is also found that the signal-to-noise ratio approximates the exponential decay of the direction of arrival error obtained by this method.

In April 1975, the Illinois Institute of Technology called the author saying that some notebooks had been found that appeared to be those of Wallace Clement Sabine. It was thought previous to this find that Sabine had destroyed all of his notebooks and papers because none was found when Professor Theodore Lyman was collecting Sabine’s papers for publication. Those notebooks were studied, a paper was published [J. Acoust. Soc. Am. 61, 355–365 (1977)], and they were deposited in the Harvard University Archives. Imagine the surprise when John Kopec called in early 1979, saying that at another location at the Riverbank Acoustical Laboratory, a pile of folders that contained some of Sabine’s consulting experiences had been discovered. John said that he had copied Sabine’s faded pages into typescript, and he invited the author to join with him in studying them and perhaps publishing a paper jointly with him. Discussed here is our work together and our publication of the results [J. Acoust. Soc. Am. 69, 367–382 ...

In a machine for processing mail articles, the method of distinguishing between mail articles (P 1 , P 2 , P 3 ) contained in envelopes made out of paper and mail articles contained in envelopes made out of plastics material, consists in displacing each mail article in front of a pressure member ( 5 ) so as to produce an acoustic signal that results from a suction effect of the pressure member on one face of said article while it moves in front of said pressure member, and in comparing said acoustic signal with a reference signal in order to detect whether the envelope of said article is made out of paper or out of plastics material.

Enhancement has been shown to occur in a variety of contexts in the papers presented here. This commentary will examine the similarities of these phenomena and look for their proper level of description within linguistic theory.

A laser‐ultrasonic (LUS) sensor has been developed that allows measurement of the bending stiffness (BS) and shear rigidity (SR) of paper and paperboard as it is being made on the papermaking machine. A prototype system was recently tested in a paper mill at web speeds up to 5000 ft/min with excellent precision and accuracy. The LUS technique performs well on paper and board with basis weights up to 130 g/m2. Several laboratory methods exist for measuring the bending stiffness in small samples of paper and board. Currently, no commercial method exists for nondestructively measuring this property on the papermaking machine at production speeds. Commercial instruments using contact transducers measure ‘‘tensile strength orientation’’ (TSO) on heavier boards, where marking of the sheet by the contact transducers is not of concern. Unlike contact ultrasonic techniques, LUS does not visibly mark even the lightest grade papers. Contact ultrasonic measurements correlate approximately to the tensile strength of the sheet and can be used to calculate an approximate value for BS. LUS measurements are directly related to BS and should yield more accurate determinations. Optimum use of feed stock, reduced waste, and decreased energy consumption are potential benefits of the LUS technology.

Laser ultrasonics has great potential for monitoring the bending stiffness of paper during on‐line operations. The temperature and humidity conditions at the paper have a significant effect on the bending stiffness, and there is a need to quantify this dependence before an on‐line system can be deployed. A laser pulsed source illuminates a point on a paper sample placed inside a controlled environmental chamber and generates ultrasound that is detected by a fiberoptic interferometer. The waveform is analyzed to extract the frequency dependence of the group velocity of the A0 lamb mode, and the corresponding bending stiffness. Three different methods of signal analysis are compared: the complex wavelet transform, the short‐time Fourier transform, and the phase‐unwrapping method, which requires measurements at two locations. The error bars associated with the bending stiffness are estimated both for the intrinsic experimental errors and for the point to point variablity in the paper itself. Results are presented for temperature ranging from 25 °C to 93 °C, and for relative humidity ranging from 2% to 75%. [Work supported by the Department of Energy and the Institute of Paper Science and Technology.]

One of the most important parts of the Society is the Journal, in which information on new research findings are disseminated. Before a paper is published in the Journal, it must be approved by an Associate Editor who typically seeks the advice of two experts on the subject of the paper. Based on 6 years experience as an Associate Editor for the Journal, an overview of several aspects involved in the review process will be given. What constitutes a good review and what reviewers are looking for in an acceptable paper will be presented. Although the decision of acceptance rests with the Associate Editor, it is rare that this Associate Editor does not adhere to the recommendations made by reviewers. However, this Associate Editor does read all of the papers prior to deciding either to accept a paper after revisions are made in response to reviewer comments, reject the paper, or defer a final decision until after the paper has been revised and submitted for further review. An overview of this Associate Edito...

There are three sections for speech communication papers in JASA: production, perception, and processing and communication systems. In contrast to some other branches of acoustics, authors of speech‐related papers have a wide variety of journals to choose from, covering several different disciplines. Among these are journals in psychology, cognitive science, linguistics, phonetics, speech and hearing science, otorhinolaryngology, neurophysiology, human movement science, and signal processing. Speech papers also cover production and perception in different human languages. In addition, papers in speech deal with both normal and clinical aspects, e.g., voice and speech disorders, and the effects of hearing impairment on speech. Papers in speech production are also concerned with analyzing articulatory movements as well as the mathematical modeling of phonation and articulation. The presentation will focus on why JASA should be a top choice for authors of papers in speech communication. Criteria for the sele...

A noncontact system is used to generate and detect, optically, a broadband ultrasonic pulse propagating in paper under controlled temperature and moisture conditions. The generation laser (Nd–Yag) produces a short optical pulse which is directed through an optical window on the paper sample inside an environmental chamber where temperature and relative humidity are controlled. Ultrasonic Lamb waves propagating in the paper are detected by a fiberoptic Mach–Zehnder interferometer (argon–ion laser) where the Doppler‐shifted light exits the chamber through a small‐core multimode fiber. The moisture content is measured by monitoring the weight of the paper sample relative to a dry sample. The dispersive nature of the A0 Lamb mode of the ultrasonic signal contains information about the bending stiffness normalized by the density and thickness of the paper averaged over the propagation path. The frequency dependence of the group velocity is found from the analytic wavelet transform of the signal (complex Morlet wavelet). [Work supported by the Department of Energy and the Institute of Paper Science and Technology.]

There are currently no models to fully predict the effects of internal wave induced scattering on acoustic pulses. Existing models, which predict time domain statistics, either use the ray-based path integral method or Monte Carlo type simulations. The path integral method fails to accurately predict all of the effects of scattering. The Monte Carlo methods base the statistics on ensemble averages and are not physics-based models. This paper overcomes these limitations by using the modes of the waveguide in a transport theory application. The transport theory equations have, thus far, been used only to explain diffusion of mode intensities and decorrelation due to internal waves at individual frequencies. This paper extends the current narrowband application predict mode correlations across different frequencies and, from that, the broadband time-front, time wander, travel time bias, and the amount of spread in intensity across time and depth. To validate these predictions, this paper uses separate parabolic equation simulations. The comparisons between the two are good, suggesting a success for the mode-based transport theory approach.

The main method to expand the operating bandwidth of the transducer is by exciting multi-order vibration modes, which develop from the earliest excitation of odd-order modes to the excitation of multi-order continuous modes. However, no detailed theoretical characterization of the excitation mechanism and electroacoustic properties of continuous-order modes has been given. In this paper, the excitation mechanism of continuous-order modes for one-dimensional thickness vibration is studied in detail. From the perspective of analytical characterization, the mathematical and physical conditions of mode excitation are analyzed and extended to continuous-order modes. Partial 1–3 piezocomposite consists of two parts; one part is complete lead zirconate-titanate and the other part is 1–3 composite, which is helpful for exciting continuous-order modes. Based on the excitation mechanism of continuous-order modes, a design method of broadband transducer used of partial 1–3 piezocomposite is proposed, and large bandwidth and good pulse response are obtained. The excitation mechanism of continuous-order modes proposed in this paper provides an idea for the theoretical analysis and design of multi-resonant broadband transducers.

In this paper, we consider the problem of bearing ambiguity in the direction of arrival (DOA) estimation due to spatial aliasing when the minimum wavelength of the processing broadband signal is less than the element spacing of a uniform linear array (ULA). First, an extended frequency-difference (FD) method is presented. Unlike the existing FD methods, the extended FD signal is constructed by conjugate multiplying a diagonal matrix consisting of steering vectors at high frequency and pre-processing direction with the array sampled signal matrix at low frequency. Then, this paper establishes a decision criterion for distinguishing the aliasing component that varies linearly with frequency in the extended FD space. Finally, an unambiguous broadband DOA estimation method is achieved by suppressing spatial aliasing in the extended FD space. The simulation results show the effectiveness of the proposed method in low signal-to-noise ratio, low signal-to-interference ratio, and multi-interference conditions. The unambiguous processing ability of the proposed method is further verified in the South China Sea using ship signals in the frequency band of 200 to 700 Hz and a 10-element ULA with a 6.25 m spacing deployed on the seabed.