bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discriminability of time-reversed click pairs: intensity effects
Authors: Resnick Steffi B. , Feth Lawrence L. 
Published: October 2005

The present investigation examined the effects of the interclick intensity ratio (ΔI) and signal level (I0) on discriminability of time-reversed click pairs. Discriminability was assessed for five normal-hearing listeners using a 2IFC procedure. The level of the more intense click (I0) was fixed at 75 or 45 dB SL. Four values of ΔI were employed such that within a click pair the more intense click exceeded the less intense click by 3, 6, 12, or 24 dB. Discriminability of the click pairs was evaluated at eight interclick intervals between 0.5 and 10.0 msec. Discriminability was altered systematically by changes in both I0 and ΔI. The interclick interval required for 75% correct discrimination ranged from less than 0.5 to 1.8 msec. The observed intensity effects suggest that discriminability of the time-reversed click pairs is predictable from temporal masking data.
Subject Classification: 65.75, 65.58, 65.50.
Tongue-pellet tracking by a computer-controlled x-ray microbeam system
Authors: Kiritani S. , Itoh K. , Fujimura O. 
Published: October 2005

A high-voltage flying-spot-type x-ray microbeam generator for computer-controlled radiography has been constructed, and a preliminary experiment on automatic tracking of pellets placed on the tongue has been conducted. Main operational features of the x-ray system are described, and some early data on the tongue movements of a Japanese subject uttering syllable sequences are shown.
Subject Classification: 70.20, 70.60.
Patterns in the sounds produced by P
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a
v
e
s
p
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a g
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m
a
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i
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a wasps
Authors: Ishay Jacob , Brown Morton B. 
Published: October 2005

In the nest of the social wasp P. germanica (Hymenoptera: Vespinae), the workers produce solid-borne tapping sounds by knocking with their bellies on the walls of the comb cells. Analysis of these recorded sounds reveals that they produce series of 20–60 beats, each containing 15–30 subbeats. The patterns of beats and subbeats are shown to be arranged in series of typical duration and spacing. Frequency analysis of the sounds reveals a peak at about 500 Hz and a range of 50–3150 Hz. The possible communicative value of these sounds is discussed.
Subject Classification: 80.50, 80.60.
Velocity of ultrasound in binary solutions of pyridine with heavy water
Authors: Stumpf F. B. , Gupta P. K. 
Published: October 2005

The velocity of sound at a frequency of 19.5 MHz was measured as a function of concentration in binary solutions of pyridine with heavy water. The velocity versus concentration studies were made at 15 °C, 25 °C, and 35 °C.
Subject Classification: 35.24.
Is it VOT or a first-formant transition detector?
Authors: Lisker Leigh 
Published: October 2005

Discussion of voicing as a distinctive property of English stop consonants in initial position has centered on the measure of ’’VOT,’’ the time of onset of laryngeal signal relative to the noise pulse generated by the stop release, but it has been shown that listeners’ selection of ‖b,d,g‖ vs ‖p,t,k‖ responses to synthetic stop+vowel stimuli is not determined entirely by VOT. Significant effects have been reported to depend on the behavior of the first formant (F1) frequency immediately following voice onset, and on this basis it has been suggested that a ’’feature detector’’ responsive to a rapidly shifting F1 better explains the infant’s discrimination of the two stop categories than some mechanism which measures VOT directly. The relative importance of VOT as against the presence versus absence of F1 frequency shift after voice onset is assayed in several synthesis experiments in which VOT and F1 configurations are systematically varied. Labeling data obtained indicate that varying VOT regularly effects a significant change in listeners’ judgments, and that varying F1 has some effect too, but this latter variation is neither necessary nor sufficient generally to shift judgments decisively from one stop category to the other. The data further suggest that the presence of an F1 rising transition after voice onset serves as a voiced-stop cue not so much because of its dynamic aspect, but simply because its onset frequency is low, i.e., at a value appropriate to a closed or almost closed state of the oral cavity.
Subject Classification: 70.30, 70.20, 70.70.
Seeding the field of acoustical signal processing
Authors: Anderson Victor C. 
Published: October 2005

This is a historical look at the contributions to the field of acoustical signal processing which originated under the nurture of F. V. Hunt at the Harvard Acoustics Research Laboratory. The early research is highlighted by the work of Faran and Hills on the use of correlators for space–time processing. This early work was followed by research in the use of multiple element arrays and by the development of real-time processors for correlation and beamforming applications. The impact of these contributions can be seen in the expanding field of signal-processing research today. Upon retirement, Hunt transferred the pursuit of his last research interest, ’’Sir Transit Sonitus’’—a ship transit detector, to the Marine Physical Laboratory, where a real-ocean investigation of the technique is currently underway.
Subject Classification: 10.60; 60.10.
Behavior of sound in a bounded space
Authors: Berman J. M. 
Published: October 2005

Theoretical predictions and reported experimental evidence of sound behavior in an enclosure are discussed and are shown in certain cases (e.g., normal-mode theory) to be inconsistent. A concrete model of a rectangular room was constructed so that the number of boundaries could be varied. Steady-state and transient responses are presented tor two-, three-, and four-boundary configurations, and these are compared with digital computations from a time-domain image simulation. The experimental results were found to be consistent with those of other researchers and the computer model was able to account for all the principal phenomena, including those at wavelengths comparable with the boundary dimensions where normal-mode concepts are usually substantiated. It was found that tone-burst responses in a bounded configuration whose reflection density increases with time can exhibit amplitude, phase, and ’’frequency’’ modulation throughout the frequency range. In reconciling these results with the normal-mode theory, the normal mode must be regarded as a mathematical function valid only in the context of an infinite series or integral in which, if principal features of the behavior are to be reproduced, the exact phase relationships are of vital importance. Finally, the tone-burst results are discussed in the light of recent work on the hearing mechanism.
Subject Classification: 55.20, 55.55, 55.40.
New methods in architectural investigations to evaluate the acoustic qualities of concert halls
Authors: Plenge G. , Lehmann P. , Wettschureck R. , Wilkens H. 
Published: October 2005

A series of experiments were conducted at a number of concert halls in order to evaluate their acoustic ’’quanlity.’’ The quality was determined from a comparison of subjective assessments of a hall with a set of specified parameters describing physical characteristics of the sound field. Notable differences in the sound field in the hall and detected by artificial heads were correlated to position, reverberation time, brilliance, and so on. Using a factor analysis a finite number of independent factors emerged. It is concluded that the quality of a hall is better described by a set of such factors rather than by a single ’’reduced’’ number, as was done in the past.
Subject Classification: 55.45.
Wide-band directivity of receiving arrays
Authors: Faran James J. , Hills Robert 
Published: October 2005

The method of maximizing the directional gain of a receiving array (heretofore useful only at a single frequency) is extended to the case of operation at a finite bandwidth. It is also shown how to design for maximum effective gain in the presence of noise which might arise within the individual transducers or their preamplifiers. Some necessary noise-field correlations are computed, and numerical examples are included to show the effects of bandwidth and self noise on the overall gain for reception which can be achieved. The directional gain of a broadside linear array for operation at a finite bandwidth is always less than that for operation at a single frequency, but is always greater, and often considerably greater, than the gain realized by use of the single-frequency design at the finite bandwidth. Unlike the single-frequency design, whose directional gain falls very rapidly as the operating bandwidth is increased from zero, the wide-band designs operate with good gain over a wide range of bandwidths.
Subject Classification: 30.82; 85.40; 60.30.
Radiation and scattering by submerged elastic structures
Authors: Junger M. C. 
Published: October 2005

Analysis of submerged vibrating structures and of the associated sound fields requires the simultaneous solution of the vibrational and acoustical problems, because surface pressures exerted by a dense medium are typically comparable to inertia and damping forces in metal structures. The scattered field generated by a submerged structure may be similarly altered by the elastic response to the incident wave. This feedback phenomenon, whereby forces exciting the structure must be combined with radiation loading dependent on the structural response, is unimportant in the atmosphere. Consequently, as underwater sound approached airborne sound in practical importance during World War I, acousticians were forced to develop new analytical and experimental techniques for studying structure–water interactions. The development of this hybrid branch of acoustics and structural mechanics is reviewed with regard to radiation and scattering. Hunt, even though never personally active in this field, was interested in its applications. He performed his characteristic function of an unselfish teacher by encouraging doctoral candidates and postdoctoral fellows in the Harvard Acoustics Research Laboratory to venture into this novel area of acoustics.
Subject Classification: 30.30, 30.40, 30.50; 10.85.
F. V. Hunt and the disc recording arts
Authors: Bauer Benjamin B. 
Published: October 2005

If necessity is the mother of invention, F. V. Hunt surely was its father. Confronted with the need to play some delicate recordings of the Harvard Tercentenary in 1936, Ted invented the first phonograph pickup capable of operation with 5-g bearing forces—a 10:1 advance in the state of the art—thereby ushering in the era of high-fidelity sound reproduction. This was followed in rapid succession by a definitive study of tracing distortion with Pierce and Lewis, including an uncanny prediction of the feasible parameters of a long-playing record. In 1941 and 1945 he received patents on inventions related to pickup and stylus structures, and in 1962 he again reduced the pickup bearing weights by an order of magnitude, producing successful 1/10th-g models which are yet to be commercialized. But Ted’s favorite saying was that he would receive most accolades for the work done through and by his students. Two among them, Frank G. Miller (1950) and James V. White (1970), made significant contributions to the understanding of a stylus–groove contact, thus laying a new theoretical basis for continued leadership of the disc record as a means of high-fidelity sound reproduction in the home.
Subject Classification: 10.60; 85.66, 85.68.
Bjerknes forces on bubbles in a stationary sound field
Authors: Crum Lawrence A. 
Published: October 2005

This paper concerns the translational forces exerted on pulsating air bubbles in a stationary sound field. These forces, normally called Bjerknes forces, are derived by simple arguments and classified as to their origin. Measurements have been made of the relative velocity of appoach of two bubbles undergoing a mutual Bjerknes force. The measurements were made in a rigid glass container oscillated in a vertical direction at 60 Hz by a shaker table. The ambient pressure above the liquid was reduced in order to obtain large pulsations, and the attracting bubbles were photographed with a movie camera. Oberved and calculated values for the velocity of approach are in agreement provided a drag law assuming interfacial slippage is used.
Subject Classification: 25.60.
Colleague’s viewpoint of F. V. Hunt
Authors: Brooks Harvey 
Published: October 2005

The influence of Ted Hunt on the career and interests of this author, while both were working at the Harvard Underwater Sound Laboratory, is detailed. Outlined are the research projects and breakthroughs which, through Ted’s inspiration and his ever-present guidance while director of the laboratory, set the pattern for most of the antisubmarine research to date.
Subject Classification: 05.60; 10.85, 10.60.
Sponsor’s viewpoint of F. V. Hunt
Authors: Pryce Aubrey W. 
Published: October 2005

Hunt’s relationship with the Office of Naval Research and his performance as an acoustics researcher on other Navy-related activities are discussed. Particular attention is given to ’’Task Order X,’’ a series of projects carried on under Navy sponsorship over a 24-year period.
Subject Classification: 05.60; 10.60, 10.30.
Acoustically induced explosions of superheated droplets
Authors: Apfel Robert E. , Harbison James P. 
Published: October 2005

A novel technique for measuring the tensile strength of liquids was recently reported [R. E. Apfel, J. Acoust. Soc. Am. 49, 145 (1971); Nature (Phys. Sci.) 233, 119 (11 Oct. 1971)]. In this technique, a droplet of the sample rises slowly in a column of another liquid, the ’’host,’’ in which it is nearly insoluble. When the droplet reaches a certain position in the host, an acoustic standing-wave field at about 50 kHz is established in the column, serving two purposes: (1) to balance the buoyancy force on the droplet and thus levitate it and (2) to rend the sample apart by raising the acoustic pressure to a great enough amplitude. If the droplet is simultaneously superheated, the cavitation event takes the form of an irreversible explosion of the sample into its vapor. Taking advantage of the levitation scheme, we have filmed this explosion with both diffuse and shadow lighting at about 3500 frames/sec; this shows resonant oscillations and what appears to be jet formation during the collapse of the vapor bubble.
Subject Classification: 35.68; 25.60.
Lagrange equations applied to flexural mode transducers
Authors: Rosato Frank J. 
Published: October 2005

This paper deals with the flexural vibrations of composite piezoelectric transducers excited by electrode pairs configured to produce electric fields in phase opposition. Lagrange equations are used to analyze the electrodynamic characteristics of the transducers. These equations are essentially equations of dynamic equilibrium constructed in terms of derivatives of the kinetic and potential functions of the electromechanical system, themselves expressed in terms of generalized coordinates. For this class of transducers, the strains and electric field are chosen as the independent variables and the electric enthalpy function is the proper thermodynamic potential for use in the Lagrange equations. The present analysis takes account of the strain-induced electric fields in the composite transducer which arises when the strain and electric field have a common direction. The generalized electromechanical equations thus derived are suitably represented by an electric network based on the classical system of analogies. A set of generalized mode impedances is defined for each vibratory mode and is shown to play a significant role in the analog network. By applying known formulas to such a network, the electrodynamic characteristics of the transducer are readily obtained.
Subject Classification: 85.52; 40.22.
Scattering of acoustic point-source fields by random surfaces
Authors: Davies Huw G. 
Published: October 2005

Estimates are obtained for the pressure field reflected from random rough surfaces when the surfaces are insonified by a high-frequency, omnidirectional point source. A geometric acoustics or ray-tracing approach is taken together with the assumptions that there is no shadowing of the surface and that each ray undergoes a single reflection. A stationary phase approximation of the Helmholtz integral is used to estimate the field associated with each ray. The emphasis of the paper is on accounting for the phase differences, that is, the interference effects, between the possibly very many geometric rays from source to surface to receiver.
Subject Classification: 20.30.
Application of ray theory to acoustic propagation in horizontally stratified oceans
Authors: Weinberg Henry 
Published: October 2005

The acoustic pressure due to a point harmonic source in a horizontally stratified ocean is represented as a multipath expansion of the integral representation. Generalized Wentzel–Kramers–Brillouin–Jeffreys solutions are used to solve the depth-dependent wave equation. By applying numerical integration in conjunction with stationary phase, the problem of caustics is eliminated. Computed predictions are compared with theoretical results and another computer model.
Subject Classification: 30.20; 20.20; 85.84.
Generalized expansions of ray theory in terms of phase velocity. I.
Authors: Pedersen Melvin A. , White DeWayne , Johnson David W. 
Published: October 2005

This is the first of a sequence of papers, which develop ray-theory expressions for velocity profiles with depth dependence only where the velocity is expressed as a generalized power series in depth. The method treats nonanalytic as well as all analytic (i.e., expandable in a Taylor series in depth) profiles. This first paper is limited to profile expansions about a velocity minimum and to the case of rays which turn around in a layer. Here the ray-theory results may be expressed as generalized power series in the phase velocity. Ray-theory range, travel time, range derivatives, phase integral function, and group velocity are treated. The method treats certain profiles, which were heretofore regarded as insolvable in closed form. Even when alternative approaches are tractable, the method has certain advantages. These include simpler and more accurate computing techniques, ease of range derivative evaluation, and improved understanding of theoretical results. Complete derivations are presented and results are verified by comparing the new method solutions with classical results for the linear, hyperbolic cosine, and exponential profiles.
Subject Classification: 30.20, 30.25; 20.20.
Validity of aircraft noise data
Authors: Sekyra C. A. , Storey W. C. , Yates R. 
Published: October 2005

An analysis of noise measurements taken at various distances from a number of aircraft during noise flight testing is presented. Data scatter is shown to increase with distance and with decreasing aircraft/observer angle. Data normalization techniques, utilizing current standards, are inadequate at large distances and low airplane/observer angles. Aircraft noise measurements taken under uncontrolled situations are of doubtful value in predicting community noise. Noise measurements obtained directly beneath the airplane flightpath, under carefully controlled conditions, are highly repeatable and adjustable for moderate distances (within 1 to 2 EPNdB); however, when adjusted to sideline distances, these data can lead to variations on the order of 5 EPNdB. The accuracy of these sideline noise estimates is of prime concern since they are used to determine aircraft noise ’’footprints’’ in noise-exposure studies. Because a 3-EPNdB change in EPNL can lead to area halving or doubling, it is concluded, based on current technology, that the use of footprints in community noise-impact studies can be extremely misleading.
Subject Classification; 50.20, 50.75, 50.80.
Development of noise-reduction concepts for the 707 airplane
Authors: Nelsen M. D. , Callaway V. E. 
Published: October 2005

Flyover noise characteristics are presented for the Boeing 707-300B/C equipped with standard production nacelles and with experimental quiet nacelles modified by the addition of sound-absorbing materials. Acoustic-treatment theory and technology required to develop the quiet nacelles are discussed. Results from, and techniques for, noise-certification flight testing to meet FAA regulations are presented. Comparisons of noise levels of a modified 707 aircraft, noise floors, and noise from other operational aircraft are provided.
Subject Classification: 50.40, 50.50, 50.55, 50.75.
Development of noise-reduction concepts for 727 and 737 airplanes
Authors: Arctander C. L. , Hodge C. G. , Tate R. B. 
Published: October 2005

A review is given of various noise-reduction concepts pertinent to JT8D-powered 727 and 737 airplanes, with emphasis on acoustic technology. Acoustic treatment for engine fan noise reduction is shown to result in production airplane configurations that comply with existing FAR Part 36 regulations for new airplanes. Two jet noise suppression concepts aimed at further 727 noise reduction are discussed. An ejector/suppressor concept that has been demonstrated in an FAA-sponsored ground and flight test program is shown to achieve 6- to 8-EPNdB suppression of jet noise at takeoff power. Airplane performance penalties, however, have precluded production application of this configuration. The refan concept, currently under development on a NASA contract, involves JT8D engine modifications to incorporate a higher work-extraction fan. This modification realizes lower jet noise that, when coupled with extensive acoustic treatment, results in significant noise reductions with a minimum impact on airplane performance.
Subject Classification: 50.40, 50.50, 50.55, 50.75.
Comparison between the growth of the averaged electroencephalic response and direct loudness estimations
Authors: Botte M. C. , Bujas Z. , Chocholle R. 
Published: October 2005

The question of the validity of the auditory-averaged electroencephalic responses (auditory AER) in auditory research and in audiometry is a very important one. In the present experiments, auditory AER and direct estimates of loudness magnitude were conducted concurrently on the same subjects, in the hope of reducing the consequences of the great within-subject and between-subject variability always encountered in such experiments, and of the differences in the degree of alertness. The peak-to-peak amplitude of the N1 − P2 waves and the N1 and P2 latencies were used as characteristics of the auditory AER. Even in these conditions, no clear relations appeared between the AER and the loudness estimations. The discussion shows that they are probably not directly connected.
Subject Classification: 65.59, 65.50.
Anthropometric manikin for acoustic research
Authors: Burkhard M. D. , Sachs R. M. 
Published: October 2005

A manikin for hearing aid and related acoustic research was designed with median human adult dimensions. Ear simulation matches the acoustic response with an auricle, an ear canal, and an eardrum that equal the median ear in dimensions, acoustic impedance and modes. Dimensions of torso and head are based on published anthropometric data, but the auricle is based on data obtained for this development. The ear canal and eardrum are adapted from the earlike coupler by Zwislocki. The ear entrance sound pressure was found to be relatively insensitive to surface or skin impedance of the head. Validating measurements show the manikin, designated KEMAR, to be like a median human in acoustic response to free fields.
Subject Classification: 65.22, 65.80, 65.35,65.82.