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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...

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.

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.

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 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.

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.

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 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.

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.

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.

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.]

Deinking remains an important step in environmentally conscious manufacturing of paper. A novel method based on acoustic microcavitation is used for deinking xerographic ink from paper. Microcavitation evolves microimplosions, which are effective in causing deinking preferentially at ink sites. Acoustic microcavitation is brought about by low megahertz acoustic fields giving rise to micron‐sized bubbles that live a few microseconds. In exposing a surface to continuous waves for a defined duration one could obtain cavitation effects in an average, overall sense; the details of nucleation, evolution of inertial events, and the precise interplay of field parameters in effecting cavitation, however, get glossed over. Studying pulsed cavitation using tone bursts at low duty cycles, instead of CW insonification, reveals interesting details of the initiation and evolution of acoustic microcavitation. Experiments indicate that the 2‐D context of how a xerographic print is deinked might be useful in inferring some...

Deinking remains an important step in environmentally conscious manufacturing of paper. A novel method based on acoustic‐coaxing‐induced microcavitation is presented for deinking of xerographic ink from paper. Microcavitation evolves microimplosions which are effective in deinking. Acoustic coaxing is an acoustic mediation that enables one to control the onset, intensity, and evolution of acoustic microcavitation. Acoustic microcavitation is brought about by low‐megahertz acoustic fields giving rise to micron‐size bubbles that live a few microseconds. Liquid‐borne microparticles when exposed to strong sound fields will not, ordinarily, cause any cavitation. However, if in addition to this sound field there exists even a very weak, high‐frequency auxiliary acoustic field, cavitation by the microparticles is readily facilitated. This technique of facilitating cavitation is referred to as ‘‘acoustic coaxing.’’ Acoustic‐coaxing methods for deinking are a chemical‐free, environmentally responsible means of recycling paper. Here, initial experimental results are presented and the technique is elaborated upon in detail for easy implementation. Preliminary results indicate that the paper fibers are entirely undamaged, and the ink separation leaves them immaculately white. The microimplosions appear to occur preferentially at the ink sites.

A paper-winding machine having a frame and supports for paper rolls carried by the frame and forming winding stations has a pair of overhead windup rollers supported on the members and flanking the rolls, and respective sound-absorbing curtains of flexible sheet material on the windup rollers and movable from positions hanging down therefrom and absorbing sound generated at the stations and positions wound up on the respective rollers.

Deinking remains an important step in environmentally conscious manufacturing of paper. Removing xerographic ink from a print sample using acoustic microcavitation provides an easy method to observe context for studying cavitation‐induced erosion at surfaces. Experiments indicate that microcavitation evolves microimplosions which are effective in causing deinking preferentially at ink sites. Acoustic microcavitation is brought about by low megahertz acoustic fields giving rise to micron‐size bubbles that live a few microseconds. In exposing a surface to continuous waves for a defined duration, one could obtain cavitation effects in an average, overall sense; the details of nucleation, evolution of inertial events, and the precise interplay of field parameters in effecting cavitation, however, get glossed over. Studying pulsed cavitation using tone bursts at low duty cycles, instead of CW insonification, reveals interesting details of the initiation and evolution of acoustic microcavitation. Specifically, ...

At present, the paper industry lacks an on‐line, noncontact quality control system. Several studies indicate that there are strong correlations between paper strength and elastic stiffness properties. These elastic properties or elastic coefficients can be determined by measuring the velocities of propagation of various ultrasonic waves. Lamb waves, for instance, propagate in paper and appear to be sensitive to paper strength. Experiments have been conducted with a laser‐based system to both generate and detect ultrasonic Lamb waves in copy paper. Results obtained regarding the relationship between the generation laser spot size, power density, and ultrasonic signal strength are presented. Paper damage is assessed at the generation spot. Phase velocity dispersion curves are produced for those modes that have sufficient signal‐to‐noise ratio. These dispersion curves are then compared to those predicted by ortotropic plate theory. [Work supported by OIP‐GT.]

An absorptive sound attenuator, which is intended particularly for intake and/or exhaust air ducts in paper mills. The sound attenuator comprises a box-like duct housing (10), in whose interior there is an inner tube (19), which is provided with through perforations (19a) and which forms the air duct (20). Around the inner tube is placed sound absorbing material (21, 22). The inner tube (19) defines the air duct (20) in its interior, the sound being absorbed in the area of the air duct (20). In order to facilitate cleaning and/or replacing of the sound attenuator components and the absorption material (21,22,26) in the duct housing (10) the absorptive sound attenuator is provided with openable outer walls (13a,13b,14a,14b,13A,13B). When these walls are open, the absorption material (21,22,26) can be removed and/or replaced from outside the inner tube (19).

The inventions concerns a sound attenuator for low frequencies for air-conditioning ducts, in particular for intake-air and/or exhaust-air ducts in paper mills. The sound attenuator comprises a frame whose flow duct substantially coincides with the air-conditioning duct and in which frame there is at least one plane attenuator member parallel to the flow direction and comprising one or several attenuator units operating by the Helmholtz and/or plate resonator principle. The attenuator member or members are fitted in the frame singly or as a group of several attenuator members to be replaced for cleaning and/or servicing of the sound attenuator and/or of the attenuator members.

Using acoustic analysis techniques, Waldstein [J. Acoust. Soc. Am. 88, 2099–2114 (1990)] reported abnormal speech findings in postlingual deaf speakers. She interpreted her findings to suggest that auditory feedback is important in motor speech control. However, it is argued here that Waldstein’s interpretation may be unwarranted without addressing the possibility of neurologic deficits (e.g., dysarthria) as confounding (or even primary) causes of the abnormal speech in her subjects.

This paper presents a critique of K. D. Kryter’s paper, ’’Community Annoyance from Aircraft and Ground Vehicle Noise’’ [J. Acoust. Soc. Am. 72, xxx–xxx (1982)] in which he purports to show that an earlier paper of Schultz, ’’Synthesis of social surveys on noise annoyance’’ [J. Acoust. Soc. Am. 64, 377–405 (1978)], significantly underestimates the annoyance associated with aircraft noise, and underestimates that due to surface traffic noise. While the earlier Schultz paper may not be entirely correct, a careful study of Kryter’s new analysis suggests that his conclusions are considerably more dubious than he regards those of Schultz.

The acoustic decoupling behavior of onionskin paper is examined, with emphasis on sonar transducer applications. Nonlinear changes in the sound velocity of onionskin paper with pressure are used to predict the degradation of both frequency and directional response. These results are obtained by computer analysis of a longitudinal‐vibrator equivalent circuit. The results are in reasonable agreement with the measured characteristics of a specific transducer configuration.

It has been previously determined that precompressed onionskin paper may be used as an acoustic decoupler. In our evaluation, compressional‐wave measurements were made on various types of paper, and in particular onionskin typing paper, at 32 and 1000 kHz. At the lower frequency, a composite material technique was used to allow pressurization of the samples. The velocity of sound and attenuation were found to vary nonlinearly with pressure over the range from 0 to 2000 psi. This nonlinearity introduces a nonlinear acoustic loading of the transducer elements and is the main disadvantage of onionskin paper. However, it was confirmed that the onionskin paper should be more stable with pressure than the other papers, provided that it has been properly precompressed. Most of the insertion loss provided by onionskin paper is caused by the mismatch in acoustic impedance. Thus, a fairly wide variety of materials should provide equivalent acoustical properties.

A program for computer retrieval of papers in acoustics is being used to search titles of all papers that have appeared in four journals over the past 13 years. Title words and author surnames are truncated to five letters. The search may be weighted Boolean, fractional, or for associated words needed to formulate a request.

This letter is in response to comments made by T. J. Schultz [J. Acoust. Soc. Am. 72, 1243–1252 (1982)] with respect to a paper by K. D. Kryter [J. Acoust. Soc. Am. 72, 1222–1242 (1982)].

In most of the following references, the author's name is followed by the title of the paper or book in boldface, the journal, the volume number in boldface, the issue number in parentheses, the page reference, and lastly, in parentheses, the year. Where reference is made to abstract journals that number their abstracts, the abstract number is given instead of a page reference. Abstracts in Annales des Tèlècommunications are in French and those for Referativnyi Zhurnal, Fizika (three series, E, I, Zh) are in Russian [where, e.g., Ref. Zh. Fiz. 7 E425 (1979) means: July issue, E, abstract no. 425, year 1979.] When possible, the abbreviations for the names of the journals follow those in Bibliographic Guide for EditorsAuthors (1974). A number preceded by the letters AD, DE, PB, or N refers to the accession/report number of the Government Reports AnnouncementsIndex. The numbers to the left of the sections and sub-sections in this volume correspond to those that appear in the Classification of Subjects preceding the index in the June 1983 issue of JASA. Compiled from various sources. For many of the journals referred to here, those interested will find their addresses in either the semi-annual Author Index of Physics Abstracts or the annual Physics Briefs: List of Abstracted Periodical and Serial Publications.

Reactions offered here (a) urge rethinking on the adequacy of a widely used criterion for defining hearing handicap in view of data referenced in the subject report, (b) criticize the author's evaluations basic to estimating hearing loss risk from known levels of noise exposure and recommending safe limits for hearing, and (c) question the use of proposed complex schemes for rating noise hazards to hearing as derived from presumed relationships between temporary and permanent noise‐induced threshold shifts in hearing.

In many paper handling machines, the sound generated by impacts is a major noise source. It is shown that in typical impact line printers both nonresonant and resonant sound generating mechanisms are significant. Both can probably be controlled by increasing the backing bar stiffness of the printer while keeping the printing force constant. It is also shown that the paper‐hammer‐backing bar impact is responsible for paper impact noise below 1250 Hz. Above 2500 Hz the hammer‐paper impact is the dominant source. From 1250–2500 Hz the two impacts contribute equally to the sound generation. Finally, consideration of the design of a “quiet” paper leads to the suggestion of a paper with high density and low bending rigidity. This might be accomplished through microcreping of the paper.

Response curves of loudspeakers have irregularities, mostly not visible in the case of a loudspeaker of good quality and measured with normal equipment. By enlarging the ordinate scale these small peaks and dips of ±2 db become visible, but with the design of a cone it is considered that these irregularities are more or less inevitable and not so serious. This opinion is strengthened because by listening tests with a variable audio‐frequency nothing abnormal can be detected. It is also impossible to measure any distortion in the region of these peaks and dips. By introducing short and sharp bursts of sine waves, however, all sorts of spurious oscillations between the bursts are visible on a cathode‐ray tube. The amplitude of these phenomena depends on the internal damping of the diaphragm, the choice of the fiber, and the degree of beating of the pulp. The purpose of this paper is to raise the following question: Is this phenomenon the cause of the apparent harshness, etc., when listening to high‐level high‐note reproduction?