bluuebunny/crossref_metadata_2025_split huggingface dataset:
Eikonal approximation and the parabolic equation
Authors: Palmer D. R. 
Published: October 2005

We discuss two aspects of the general problem of sound propagation in an ocean characterized by a range-dependent profile. We first consider a normal-mode formalism for describing a situation in which the eikonal approximation can be applied in the horizontal plane. The difficulty with this approach is shown to be an ordering in the geometric optics path-length parameter due to mode coupling. By example we indicate how this difficulty can be overcome. We then use the formalism to discuss the approximations which make up the parabolic equation method. The parabolic equation is derived by assuming the eikonal approximation in the horizontal plane and a degenerate spectrum approximation. The degeneracy approximation is reflected in a stationary phase approximation to an integral representation for the pressure field. We then derive improved equations by relaxing these assumptions. We relax the degeneracy assumption by considering an improved stationary-phase approximation and we relax the eikonal assumption by considering the ’’supereikonal’’ approximation.
Subject Classification: [43]30.20, [43]30.25, [43]30.50.
New approach to the analysis of monolithic crystal filters
Authors: Akcakaya E. 
Published: October 2005

Using thickness-shear approximation theory and interpreting certain boundary conditions as torque or displacement drivers, a multiterminal component for each region of a definite multielectroded quartz structure (monolithic filter) is established. Repeating the same idea for shear-flexure approximation theory is complicated; however, more complete multiterminal component models are obtained for the regions. Such models make it possible to analyze monolithic quartz filters by ’’tearing and reconstruction technique’’ (i.e., by Diakoptics). The expressions for the insertion-loss function of a monolithic filter are derived by using both approximation theories, and computational results are given.
Subject Classification: [43]85.32; [43]40.65; [43]85.52.
Ultrasonic studies on the head oil of the North Atlantic pilot whale (Globicephala melaena melaena)
Authors: Blomberg Jonas , Jensen Bo Nordy 
Published: October 2005

Head oil extracted from a sample of the melon was studied. Sound velocity and sound absorption data are presented. The data support the notion that some refraction of ultrasound will occur in the melon as the sound velocity of the head oil, comprising 80% of its weight, is lower than that of sea water. Deducing from these results the lens action of the melon seems not to be strong enough to explain the high directionality of the sound emitted in echolocation along, but suggests a cooperative refraction and reflection model. The data furthermore indicate a strong dependence on water temperature of the refractivity of the melon. An attempt is made to correlate the chemical composition with the sonic properties of the oil.
Subject Classification: [43]80.45, [43]80.50; [43]80.20.
Jet drive mechanisms in edge tones and organ pipes
Authors: Coltman John W. 
Published: October 2005

Measurements of the phases of free jet waves relative to an acoustic excitation, and of the pattern and time phase of the sound pressure produced by the same jet impinging on an edge, provide a consistent model for Stage I frequencies of edge tones and of an organ pipe with identical geometry. Both systems are explained entirely in terms of volume displacement of air by the jet. During edge-tone oscillation, 180° of phase delay occur on the jet. Peak positive acoustic pressure on a given side of the edge occurs at the instant the jet profile crosses the edge and starts into that side. For the pipe, additional phase shifts occur that depend on the driving points for the jet current, the Q of the pipe, and the frequency of oscillation. Introduction of this additional phase shift yields an accurate prediction of the frequencies of a blown pipe and the blowing pressure at which mode jumps will occur.
Subject Classification: [43]75.60.
Resolution performance of Doppler ultrasound flowmeters
Authors: Griffith James M. , Brody William R. , Goodman Lester 
Published: October 2005

Ultrasonic Doppler flowmeters can simultaneously obtain spatial and velocity distribution patterns of flow in a blood vessel. The factors fixing spatial and velocity resolution, however, must be determined if optimum utilization is to be realized. The parameters influencing spatial resolution have been described in the literature, but velocity resolution has received relatively little attention. This paper demonstrates analytically how optimum velocity resolution can be derived with a simple mathematical model and presents experimental data to verify theory. In addition, a ’’resolution product’’ is offered which characterizes pulsed Doppler flowmeters. This product shows explicitly the necessary compromise between position and velocity resolution for a given instrument.
Subject Classification: [43]28.60, [43]28.20; [43]80.70; [43]35.80.
Improved acoustic viscosimeter technique
Authors: Fisch M. R. , Moeller R. P. , Carome E. F. 
Published: October 2005

An improved technique has been developed for studies of the shear viscosity of fluids. It utilizes an acoustic resonator as a four-terminal electrical device; the resonator’s amplitude response may be determined directly and simply related to the fluid’s viscosity. The use of this technique is discussed briefly and data obtained in several fluids is presented.
Subject Classification: [43]35.10, [43]35.68; [43]85.52.
Excitation, detection, and scattering of electroelastic surface waves via an integral equation approach
Authors: Sabbagh Harold A. , Krile Thomas F. 
Published: October 2005

The problem of the excitation, detection, and scattering of electroelastic surface (Bleustein) waves is solved exactly by determining the charge distribution on the fingers of an interdigital transducer. The approach is to solve an integral equation, in the Fourier transform domain, that relates the charge density on the fingers to the electric potential of the fingers. The solution of the integral equation is accomplished by expanding the charge distribution in a series of pulses and then transforming the problem to a vector matrix,one which is readily handled by a computer. In this manner the charge distribution is determined for a variety of conditions.
Subject Classification: [43]35,54.
Uniform spinning cable as a vibration absorber
Authors: Vance O. L. , Woodward J. H. 
Published: October 2005

This paper presents an analysis of the free vibrations of a disk–cable system spinning freely about a fixed axis through the disk center. Secondly, it is shown how the cable can be used as a vibration absorber to reduce the effect of torsional disturbances on a rotating system.
Subject Classification: [43]40.22, [43]40.70.
Optical holography for the study of sound radiation from vibrating surfaces
Authors: Hansen Colin H. , Bies David Alan 
Published: October 2005

Time-averaged holography has been used to quantitatively investigate sound radiation from an edge-clamped circular flat plate mounted in an infinite rigid baffle. For a particular mode of vibration, the plate response is measured using holography and the sound power radiated is measured in a reverberant room with the plate mounted in one of the room walls. From these measurements a radiation efficiency is determined. The theoretical plate responce is calculated using both classical and Mindlin–Timoshneko plate theory and is shown to agree well with experimental measurements. Radiated sound power is calculated for each mode of interest by solving the wave equation in oblate spheroidal coordinates at the plate surface. These calculations are verified by direct evaluation of the Rayleigh integral in the farfield. Good agreement is obtained between experimentally measured radiation efficiencies and theoretical predictions. Small discrepancies between theory and experiment are discussed.
Subject Classification: [43]20.55, [43]40.24, [43]35.65.
On parametric source aperture factors
Authors: Moffett Mark B. , Mellen Robert H. 
Published: October 2005

It is well known that the beam pattern of a parametric acoustic source whose difference frequency is generated largely within the nearfield of the primary beam includes a multiplicative aperture factor that can be important at large angles when ka≳1 (k is the difference frequency wave number, a is the aperture radius). Not so well known, however, is the fact that the same aperture factor arises in the case of a spherically spreading, conical primary beam of finite initial aperture. The importance of the aperture size in determining the off-axis behavior of parametric sources is discussed.
Subject Classification: [43]25.35; [43]20.30; [43]30.75.
Alternative test method for evaluating impact noise
Authors: Schultz Theodore J. 
Published: October 2005

The current method of measuring impact noise transmission involves the use of a standard hammer machine to produce a series of impact on the floor-ceiling structure, and the measurement of the resulting noise produced in the room below. The method has been criticized on the ground that ratings based on the test data correlate poorly with the subjective judgments of people listening to real-life impacts on the same floors. An alternative test method is proposed that uses a modified hammer machine whose internal impedance, intensity of impact, and striking frequency simulate those of real footfalls. The new method involves several changes from the present standard: short-term rms impact sound levels are measured instead of long-term rms levels; no normalization for the sound absorption of the receiving room is required; since the short-term levels are higher than the long-term levels usually measured, background noise is less of a problem than for the existing method. These proposed changes based on recent studies are expected to improve the correlation between test data and subjective judgments of floors.
Subject Classification: [43]55.80; [43]50.45.
Identification of random auditory waveforms. III. Effect of interference
Authors: Pollack Irwin 
Published: October 2005

The identification of specific random waveforms, imbedded within random interference, was examined. Backward interference (interference after the specific waveform) was more effective than forward interference (interference before the specific waveforms). The accuracy of identification with combined interference (interference before and after the specific waveforms) is approximated by an independence model of interference. Under the present test conditions, interference with the identification of specific random waveforms is interpreted to be more nearly related to the interruption of auditory processing than to the masking of signal audibility.
Subject Classification: [43]65.58, [43]65.75, [43]65.52.
Speech sound discrimination by monkeys and humans
Authors: Sinnott J. M. , Beecher M. D. , Moody D. B. , Stebbins W. C. 
Published: October 2005

Old World monkeys were trained with an operant conditioning technique to discriminate the natural speech sounds /ba/–/da/ and transferred to synthetic speech. Human and monkey difference thresholds for formant transitions were then compared along a seven-step /ba/–/da/ continuum. Monkeys were not as sensitive as humans to differences in formant transition: the just noticeable difference for monkeys was about 320 Hz, and for humans, about 160 Hz. Although humans were more adept at intraphonemic discriminations than monkeys, their latencies to stimulus changes revealed evidence of ’’categorical perception’’ of the continuum: While latencies for the monkeys increased linearly as stimulus difference was decreased, human latencies were essentially constant for all interphonemic comparisons, but increased sharply for intraphonemic comparisons. We view these data as evidence for (a) similar sensory capacities in monkeys and humans, but (b) unique speech processing capacities in humans.
Subject Classification: [43]65.75; [43]70.30; [43]80.50.
An investigation of speaker height and weight identification
Authors: Lass Norman J. , Davis Margaret 
Published: October 2005

The purpose of this investigation was to determine if listeners were capable of speaker height and weight identifications from recorded speech samples. A standard prose passage was recorded by 30 speakers, 15 females and 15 males. A master tape containing the randomly arranged recorded readings of all speakers was played to a group of 30 subjects for speaker height and weight identification purposes. All subjects participated in two experimental sessions. In one session they were asked to determine the height of each of the speakers on the tape, and in another session weight judgments were made. The order of presentation of the height and weight tasks was randomized so that 15 subjects made height judgments first while 15 subjects made weight judgments first. A multiple-choice response sheet containing four choices for the judgment of height and weight for each speaker was provided. Results indicate that the subjects were capable, with slightly better than chance guessing accuracy, of identifying the heights of male and female speakers and the weights of male speakers when presented with only their recorded speech samples. Implications of these findings and suggestions for future research are discussed.
Subject Classification: [43]70.30.
A method for the experimental evaluation of the acoustic characteristics of an engine exhaust system in the presence of mean flow
Authors: Kathuriya M. L. , Munjal M. L. 
Published: October 2005

The paper deals with an exact analysis of standing waves in an impedance tube with mean flow. A method is offered for the experimental evaluation of the various wave parameters. Navier–Stokes equations have been solved for evaluating the volume velocity taking into account mean flow, viscosity, etc. The engine exhaust system has been characterized as an acoustic source with an acoustic pressure and internal impedance. A method is suggested for the evaluation of these hypothetical parameters using the exhaust pipe as an impedance tube.
Subject Classification: [43]85.20; [43]20.40.
Hearing protector rating
Authors: Behar Alberto , Taibo Lucía , Raitzin Carlos 
Published: October 2005

A direct comparison between the attenuation of different hearing protectors becomes difficult because it involves curves instead of numbers. Following the well-known technique developed in building acoustics concerning the rating of sound attenuation of partitions by using standard profiles, a new method for rating hearing protectors is proposed.
Subject Classification: [43]85.88.
Optimizing the monotone performance of electrodynamic drivers using tubular couplers
Authors: Finch R. D. , Higgins P. W. 
Published: October 2005

A theory is presented for the design of resonant cylindrical couplers to be used with electrodynamic transducers to produce intense monotone signales in air. It is shown that for a given transducer there are different couplers which maximize radiation efficiency, or maximize radiated power, or which produce ρc loading in a connecting tube. The latter coupler loads the transducer as if it were connected to an infinitely long tube of the same diameter as the connecting tube. Several commerical transducers are examined to determine their radiation performance characteristics when loaded by suitable couplers. It is concluded that transducers are available which, when properly loaded by a cylindrical coupler, are capable of meeting the radiation requirements for devices such as an acoustic detection and ranging system. For example, a 200 Welect-rated commerical transducer may be made to radiate approximately 100 Wacoust when connected to a correctly designed quarter-wavelength cylindrical coupler.
Subject Classification: [43]85.40, [43]85.42.
Underwater acoustic scatter channels with several bounces
Authors: Tuteur Franz B. 
Published: October 2005

This paper deals with scattering channels involving signal paths that are reflected several times from the boundary on their way from the transmitter to the receiver. The transmitted signal is a single-frequency sine wave, and the surfaces from which it is reflected are regarded as being statistically independent. Therefore the autocorrelation function of the received signal has a very simple form consisting mainly of the product of the characteristic functions of the various reflecting surfaces.
Subject Classification: [43]30.20; [43]30.40.
Dead-zone limiter: An application of conditional tests in nonparametric detection
Authors: Kassam Saleem A. , Thomas John B. 
Published: October 2005

The concept of a conditional statistical test is applied to obtain a nonparametric detector based on the dead-zone limiter nonlinearity. The resulting detector is easily implemented, and its performance is shown to be superior to that of the sign detector for both large and small samples.
Subject Classification: [43]60.20,[43]60.30.
Mode theory of wave propagation in a bilinear medium: The WKB approximation
Authors: Hall Marshall 
Published: October 2005

Normal-mode calculations are made of wave propagation in a bilinear medium with a free surface (the surface duct). The WKB approximation is used. In the usual way, the integral expression for the field is transformed into an infinite series of the residues (normal modes) of the integrand at its poles (eigenvalues). Approximations for the eigenvalues of the trapped normal modes are obtained from WKB formulas. The eigenvalues of the untrapped modes are obtained by quadratic extrapolation of the eigenvalues of the trapped modes. The accuracy of the real part of the eigenvalues of all modes is improved by taking into account the imaginary part when solving the characteristic equation. On comparing a number of WKB calculations of transmission loss with exact calculations, it is found that when there is little fine structure in the transmission loss curve, the WKB result is a good representation of the exact result. When there is significant fine structure, however, the WKB results are often in error by several decibels, and occasionally by up to 20 dB.
Subject Classification: [43]30.20; [43]20.15; [43]30.50.
Age as a factor in susceptibility to hearing loss: Young versus adult ears
Authors: Price G. Richard 
Published: October 2005

In order to test the relative susceptibility of young and adult ears to loss from intense stimulation, losses in round window cochlear microphonic (CM) sensitivity and hair cell losses were compared in series of experiments using 52 eight-week old kittens and 59 adult cats. In acute experiments, ears of deeply anesthetized animals were exposed to 50 min of 5.0-kHz pure tone stimulation at that intensity necessary to produce a maximum CM output (MAX+0), or 10 dB(MAX+10) or 30 dB(MAX+30) higher than that. In chronic experiments, similar measures were made and the animals were allowed to recover for six weeks before their sensitivity was remeasured and their cochleas examined by surface preparation histology. Losses were the same at MAX+0, but at MAX+10 the kittens lost significantly more sensitivity than the cats. At MAX+30 the losses were large (45–50 dB) but not significantly different. The chronic experiments showed that some CM recovery did occur and that hair cell losses were orderly and generally confined to the areas of the basilar membrane involved in the displacement pattern for a 5.0-kHz tone.
Subject Classification: [43]65.64, [43]65.40.
Noise-intensity discrimination: Effects of bandwidth conditions and mode of masker presentation
Authors: Schacknow Paul N. , Raab David H. 
Published: October 2005

Noise-intensity discrimination was studied as a function of both signal and masker bandwidth. Five bandwidths of noise—ranging from 100 to 10 000 Hz—were employed. Maskers were presented at each of three spectrum levels (5, 25, and 45 dB re 0.0002 μbar). Discrimination thresholds were relatively unaffected by changing bandwidth over a two-decade range when the signal and masker were filtered together, with either continuous or gated presentation of the masker. When the masker bandwidth was greater than that of the signal, the reciprocity between signal power density and signal bandwidth was found to be 5 dB per log unit of bandwidth with continuous maskers and 5–10 dB (depending upon level) with gated maskers. The results were compared with predictions of energy-detector models of noise-intensity discrimination. Modifications of simple energy-detection schemes were discussed.
Subject Classification: [43]65.58, [43]65.75, [43]65.50; [43]50.70.
Identification of vowels excerpted from /l/ and /r/ contexts
Authors: Bond Z. B. 
Published: October 2005

Two experiments were conducted investigating the identifiability of vowels excerpted from context. Five phonetic contexts were investigated: neutral (h-d), initial and final /l/, and initial and final /r/. Vowels were excerpted from these contexts by computer and presented to subjects for identification. The consonantal contexts of initial and final /r/ and /l/ affected the identification of the excerpted vowels in various systematic ways, as compared with the identification patterns of vowels excerpted from the neutral context.
Subject Classification: [43]70.30, [43]70.40.[43]70.62.
Separation of speech from interfering speech by means of harmonic selection
Authors: Parsons Thomas W. 
Published: October 2005

A common type of interference in speech transmission is that caused by the speech of a competing talker. Although the brain is adept at clarifying such speech, it relies heavily on binaural data. When voices interfere over a single channel, separation is much more difficult and intelligibility suffers. Clarifying such speech is a complex and varied problem whose nature changes with the moment-to-moment variation in the types of sound which interfere. This paper describes an attack on the principal subproblem, the separation of vocalic speech. Separation is done by selecting the harmonics of the desired voice in the Fourier transform of the input. In implementing this process, techniques have been developed for resolving overlapping spectrum components, for determining pitches of both talkers, and for assuring consistent separation. These techniques are described, their performance on test utterances is summarized, and the possibility of using this process as a basis for the solution of the general two-talker problem is briefly considered.
Subject Classification: [43]70.62, [43]70.60, [43]70.65.
Effects of selected vocal disguises upon spectrographic speaker identification
Authors: Reich Alan R. , Moll Kenneth L. , Curtis James F. 
Published: October 2005

This research was designed to investigate the effects of selected vocal disguises upon spectrographic speaker identification. The experiment consisted of open-trial, spectrogram-matching tasks with 15 ’’reference’’ and 15 ’’matching’’ speakers. The speakers produced two sentence sets in six different ways: (1) normal-speaking mode, (2) old-age disguise, (3) hoarse disguise, (4) hypernasal disguise, (5) slow-rate disguise, and (6) free disguise of his own choosing. The reference spectrograms were always undisguised speech samples; the matching spectrograms were either disguised or undisguised. Four trained spectrographic examiners completed the matching tasks. The results revealed that the examiners were able to match speakers with a moderate degree of accuracy (56.67%) when there was no attempt to vocally disguise either utterance. The inclusion of disguised speech samples in the matching tasks significantly interfered with speaker-identification performance. However, certain voice disguises were more effective than others. In addition, certain speakers were considerably more difficult to identify than others. In summary, this investigation did not substantiate prior claims that spectrographic speaker identification is unaffected by attempts at disguising one’s voice.
Subject Classification: [43]70.65, [43]70.40.