bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffraction Effects in the Ultrasonic Field of a Piston Source
Authors: Bass R.
Published: September 2005

Diffraction effects in the ultrasonic field of a circular piston source are discussed with particular reference to the measurement of ultrasonic absorption in liquids by the pulse technique at frequencies of 1 Mc/sec and above. A relationship given by Williams for the acoustic pressure, integrated over a “measurement circle” equal in area to and coaxial with the source, is used to develop a new formula representing the apparent attenuation due to diffraction. This is simpler and more general than the corresponding formula derived by Williams. It covers all distances between source and detector larger than the radius of the source irrespective of the ultrasonic wavelength in the medium. Measurements made in water at frequencies of 1 and 3 Mc/sec confirm the theory qualitatively.
Nonstationary Excitation and Response in Linear Systems Treated as Sequences of Random Pulses
Authors: Lin Y. K.
Published: September 2005

The problem of the nonstationary excitation and, hence, the nonstationary response of a linear system is treated by assuming that the excitation is a superposition of random pulses. Under this assumption, the response is another superposition of random pulses. The simplest case in which the excitation is a non-stationary shot noise—that is, the excitation pulses are the Dirac impulses that arrive according to a non-homogeneous Poisson probability law—is considered first. The log-characteristic functional of the response process, which gives complete statistical information about the response, is obtained. Then, consideration is extended to an arbitrary shape for the excitation pulses and to non-Poisson pulse arrivals. For use in the frequency-domain analysis of the second-order statistics, the expressions are given for the generalized spectral density of the excitation or the response process. Finally, an example is included for illustration.
Acoustic Radiation Force
Authors: Olsen Haakon , Wergeland Harald , Westervelt Peter J.
Published: September 2005

A formula for the force on an arbitrary scatterer is derived without making any assumptions about the scatterer.
Fluctuation of Sound Pulses Transmitted Vertically in the Sea
Authors: Nanda J. N. , Rao V. N.
Published: September 2005

This paper discusses the advantages of studying fluctuations of underwater sound in vertical transmission and points out the drawbacks of the horizontal transmission studies. Certain experiments eliminating avoidable known causes of fluctuations have been carried out at the Indian Naval Physical Laboratory and are described. The results show that the variation coefficient of fluctuation has a higher value than those reported by other workers in other areas. The suggestion put forward by Nanda that scattering by zooplankton may be responsible for this large fluctuation is supported.
Experimental Comparison between Noise from Unheated Subsonic Air Jets Having 4:1 Elliptic and Circular Orifices
Authors: Powell Alan
Published: September 2005

This note describes a short series of experiments investigating the nature and magnitude of the differences in the noise field from subsonic cold air jets having circular and elliptic orifices. An anticipated increase in the noise level occurs in directions normal to the major axis, but other changes having more obscure origins are also revealed.
Comparison of Theory and Experiment for Forced Sound-Wave Propagation in Rarefied Gasdynamics: Reply to “Comments on ‘Propagation of Forced Sound Waves in Rarefied Gasdynamics’” [G. Maidanik and H. L. Fox, J. Acoust. Soc. Am. 38, 477–478(L) (1965)]
Authors: Sirovich Lawrence , Thurber James K.
Published: September 2005

The comparison of theory with experiment for rarefied-gas sound propagation is discussed. It is shown that the salient comments of Maidanik and Fox [J. Acoust. Soc. Am. 38, 477–478(L)(1965)] in connection with our paper [J. Acoust. Soc. Am. 37, 329–339 (1965)] are either incorrect or unfounded. It is shown by means of estimates on the percentage of inter-molecular collisions occurring in present-day high-Knudsen-number experiments that the plane-wave propagation described in our paper is still a significant effect.
Proposed Massless Remote Vibration Pickup
Authors: Stewart Chandler
Published: September 2005

A method is proposed for the remote measurement of vibrations, by detecting the frequency modulation in a microwave beam reflected by the vibrating surface. It offers the possibility of permitting rapid scanning for vibration patterns, of avoiding loading effects, and of unusually wide band response. Rough calculations predict displacement sensitivities below a micron, from a system using a 20-milliwatt klystron source. Also, soil impedance measurements appear possible with less than a milliwatt of driving power.
Re-Vision of the Speech-Privacy Calculation
Authors: Young Robert W.
Published: September 2005

The articulation index used in telephone communication, the listening equation for sonar, and the acoustical-privacy calculation of architectural acoustics are all founded on a computation of an excess of signal level over noise level just sufficient to permit some stated detectability. From this viewpoint, data compiled for “Speech Privacy in Buildings” by Cavanaugh, Farrell, Hirtle, and Watters [J. Acoust. Soc. Am. 34, 475–492 (1962)] have been reviewed for possible simplications in their procedure for estimating acoustical privacy. Interrelations are demonstrated among various current methods for rating noise and sound insulation, and a general equation for acoustical privacy is derived. As an example, for the case of “confidential” privacy, 200-ft2 floor area, and raised voice, satisfactory acoustical privacy is to be expected if D+NA = 85 dB, where D is the sound isolation between the rooms (the reduction of sound from one room to the next) as rated by a procedure like that for the sound-transmission class, and NA is the background-noise level in the receiving room measured with a sound-level meter on A-weighting.
Effects of Localized Hypoxia on the Electrophysiological Activity of Cochlea of the Guinea Pig
Authors: Misrahy G. A. , De Jonge B. R. , Shinabarger E. W. , Arnold J. E.
Published: September 2005

Solutions of glucose oxidase and its substrate were injected into the scalae to render the organ of Corti hypoxic without affecting oxygen tension in the stria vascularis. It was thus possible to depress action potentials and microphonics, leaving the dc potential largely unaffected, to suppress entirely the action potential of a tone pip of 12 000 cps without similarly suppressing that of 1000 cps, and to diminish the microphonics in one turn without detecting the decrease with an electrode placed in another turn or against the round window. These results were taken to show that the dc potential originates in the stria vascularis, that a tone of 12 000 cps elicits an action potential only in the first cochlear turn, and that a unipolar electrode records only from a limited distance.
Continuity Effects with Alternately Sounded Noise and Tone Signals as a Function of Manner of Presentation
Authors: Elfner Lloyd , Caskey William E.
Published: September 2005

An experiment is reported on continuity effects produced in a longer-duration, less-intense noise signal alternating with a shorter-duration, higher-intensity tonal signal. The perceived continuity in the noise signal is demonstrated to be significantly affected by the following: (1) the frequency of the tonal signal (200, 400, 1000, 2000, and 4000 cps), (2) the duration of the noise signal (70, 250, and 950 msec), and (3) the manner of presentation (monaural versus dichotic). Monaural thresholds were found to be larger than dichotic continuity thresholds. Continuity effects were demonstrated under dichotic presentation. That is, the noise signal was reported as continuous when interrupted for periods of time that would be clearly perceived if no tonal signal were interpolated the interruptions of the noise. A two factor theory is forwarded to explain the dichotic and monaural continuity effects. The monaural effects are discussed in terms of rate of decay of auditory sensation. The dichotic effects are discussed in terms of facilitation of ongoing neural discharge somewhat more central than the first-order neurons.
Noise Origin, Power, and Spectra of Ducted Centrifugal Fans
Authors: Howes F. S. , Real R. R.
Published: September 2005

Forward and backward curved blade centrifugal fans as noise sources were subjected to an extensive study, measurements being made in a duct with an acoustic termination. The data obtained support the following conclusions:

(1) The noise output from each homologous series of fans can be defined by one V-shaped specific noise power vs log specific speed curve, with minimum close to maximum static efficiency.

(2) Fan outlet noise power at maximum fan efficiency approximates 10−5 times the input fan power.

(3) The noise origin is primarily blade and air flow boundary turbulence.
Automatic Recognition of Phonetic Patterns in Speech
Authors: Dudley Homer , Balashek S.
Published: September 2005

The mechanical recognition of ten spoken words (the digits) with near-perfect precision has been demonstrated under laboratory conditions for a single talker after optimum circuit adjustment for his voice. Such word recognition points to the possibility of automatic voice writing and other voice-controlled operations.

The device described is based on two principles—the recognition of sustainable patterns of power versus frequency in speech, and the recognition of the durations of such phonetic patterns in words.

An alphabet of only ten patterns is proven adequate for limited word recognition, at least in the case of a single talker. The successful performance of the ten-word digit recognizer for voice dialing of telephone numbers was recorded on a motion picture film shown in the oral presentation. Data from the film are discussed in this paper.

This paper describes a working model of a phonetic pattern recognizer built at Bell Telephone Laboratories based on a detailed power-frequency spectrum analysis. Tests, to be discussed, indicate that this device, which supersedes an earlier model, leads to almost perfect digit recognition when set for a particular voice. The device also offers outstanding possibilities in speech transmission. The former application will be described in this paper and the latter in a companion paper.
Segmentation Techniques in Speech Synthesis
Authors: Peterson Gordon E. , Wang William S-Y. , Sivertsen Eva
Published: September 2005

A basic method of speech synthesis is described in which discrete segments of recorded utterances are joined together to produce continuous speech. The segments are characterized as (a) containing parts of two phones with their mutual influence in the middle of the segment, and (b) beginning and ending at the phonetically most stable position of each phone. All segments containing the same articulatory sequence have been defined as a dyad. The method of synthesis described includes not only articulatory phones, but also intonation, stress, and duration. A large number of segments is required and various techniques of obtaining the segments for speech synthesis are discussed. The method is limited to a specific dialect, and practically it is limited to a single speaker.
Coupling between Two Modes of Vibration in a Piezoelectric Resonator
Authors: Redwood M.
Published: September 2005

Two coupled modes of vibration are sometimes observed with piezoelectric-ceramic resonators in which a single mode is expected. The coupling is inferred through the presence in the admittance characteristic of two close resonance peaks; it is also seen through a nonexponential decay of resonant vibrations. The effect is attributed to a perturbation of symmetry (such as a flaw in the material or imperfect geometry) that permits coupling of the principal piezoelectric mode to some other secondary mode whose resonance is close in frequency. To determine the requirements for obtaining coupling, a split-electrode system was used on a thin, rectangular, ceramic plate to measure the resonant frequencies of the first three extensional modes (length, edge, radial) and first three face-flexural modes, the dimensions being varied from a length/width of 6:1 to 1:1. Coupling between the length mode and second flexural mode was investigated in detail, using a plate of length/width 3.5:1, resonant at 45 kc/sec. Perturbations of symmetry were obtained by adding or removing mass at a corner; coupling could be produced by a change in mass of the order of 10−3 of that of the whole resonator. The experiments show the modification of the electrical characteristics of the principal piezoelectric resonance as the coupling to a secondary mode of the same frequency is increased and, also, the effect of coupling two modes of different frequency. The results are discussed qualitatively in terms of an equivalent electrical circuit.
Distinctive Features and Errors in Short-Term Memory for English Vowels
Authors: Wickelgren Wayne A.
Published: September 2005

Errors in short-term recall of six English vowels (I, ε, æ, U, ʌ, ɑ) were tabulated and related to several distinctive-feature systems. Vowels were embedded in two contexts: /l[ ]k/ and /z[ ]k/. Subjects were instructed to copy items as they were presented, followed by recall of the entire list of (six) items. Perceptual errors were excluded from the recall error matrix by scoring for recall only correctly copied items. The rank-order frequency of different intrusions in recall of each presented vowel was almost perfectly predicted by a conventional phonetic analysis in two dimensions: place of articulation (front, back) and openness of the vocal tract (narrow, medium, and wide). The error matrix also supported the assumptions that the values of openness are ordered in short-term memory and that the correct value on the openness dimension is more likely to be forgotten than the correct value on the place dimension. The study suggests that a vowel is coded in short-term memory, not as a unit, but as a set of two distinctive features, each of which may be forgotten independently.
Optical Methods for the Ultrasonic Determination of the Elastic Constants of Sapphire
Authors: Mayer Walter G. , Hiedemann E. A.
Published: September 2005

Three optical methods, formerly only used for isotropic media, are applied to find the ultrasonic velocities in sapphire. From the results the elastic constants are calculated for this crystal. The elastic moduli are determined from measurements of ultrasonic velocities in different crystallographic directions, and Young's modulus is plotted as function of these directions.
Plane-Wave Scattering from a Rough Surface with Correlated Large- and Small-Scale Orders of Roughness
Authors: Hayre H. S. , Kaufman D. E.
Published: September 2005

A rough surface is assumed to be composed of a slowly varying large-scale roughness and a rapidly varying small-scale roughness, and it is assumed that these are correlated. The exponential forms of both the autocorrelations of these surfaces and their crosscorrelation were used. This paper shows that the return from such a composite surface for a plane-wave incidence can have either one of the following terms contribute a major portion of the total return power: namely, the large-scale roughness term, small-scale roughness term, and the crosscorrelation term. It is therefore concluded that contribution due to each term must be evaluated before neglecting its effect on the total return power. These results are equally applicable to acoustic and radar cases.
Attenuation and Dispersion of Sound by Solid Particles Suspended in a Gas
Authors: Zink Jay William , Delsasso L. P.
Published: September 2005

Observations were made on audio-frequency sounds propagating through a gaseous medium containing small solid particles in suspension. Two effects were observed, the attenuation and the dispersion. The measurements were carried out by sending short trains of sine waves through the particle-filled gas and observing the changes in the transmitted train of waves after the particles settled out of the gas. The variation in arrival time of the pulse was used to determine the velocity change caused by the suspended particles. Changes in the amplitude of the received pulse made it possible to determine the additional attenuation due to the suspended particles.

The variations of the attenuation and velocity with frequency due to the particle-filled gas were obtained and the results compared with theory. The measured attenuation was found in good agreement with existing theory. The observed dispersion satisfactorally accounted for by a theory that is introduced in this paper. The attenuation theory takes into account enhanced viscous and thermal losses caused by the suspended particles. The dispersion theory predicts the velocity shift resulting from changes of the heat capacity and density of the gas containing the suspended particles,
Rotationally Symmetric, Transient Response of a Small-Angle Truncated Conical Shell owing to a Moving Pressure Front
Authors: Bluhm Joseph L. , Neal Donald
Published: September 2005

A thin, truncated conical shell is analyzed for the initial transient response due to the passage of a pressure front of constant velocity and amplitude. The principle of virtual work is applied to a segment of the shell, between two adjacent generatrices, treated as a beam on an elastic foundation. The ends of the shell are considered to be simply supported. The natural or free modes of vibration are approximated using an 8-term series of functions each satisfying the boundary conditions, and the resulting modes are used in conjunction with time-dependent coefficients to formulate the forced response.
Influence of Shear Flow on Sound Attenuation in a Lined Duct
Authors: Tack D. H. , Lambert R. F.
Published: September 2005

A theoretical and experimental study of the influence of shear flow on the attenuation of sound in a lined duct is presented. Both upstream and downstream propagation are considered. Solutions of the linearized equations for acoustic-wave propagation in flow, based upon both uniform and power-law models of the mean-flow profile, are compared with attenuation measurements in a duct having two opposite side walls lined with a porous fiberglas® blanket for a frequency-geometry range kδ⩽1 and midstream Mach numbers Ml<0.2. Here, k is the plane wavenumber and δ is the aerodynamic boundary-layer thickness. Both profile models yield results in close agreement with experiments at low frequencies, kδ<0.1. For intermediate and high frequencies, 0.1 <kδ<1, the uniform-flow model fails, as expected, since it can only account for the convective effects of the flow upon attenuation of sound. It was not expected that the power-law model, which seemingly accounts for the effects of both convection and refraction within the shear layer upon the sound wave, would yield results much the same as those obtained for the uniform-flow profile, and thus fail in various degrees for this frequency range. Also, scattering of sound by turbulent flow does not appear to be strong enough to account for discrepancies between theory and experiment. As a result, the problem of accurately predicting the effects of refraction upon sound attenuation in the range 0.1 <kδ <1 remains unsolved. The uniform-flow model, for which solutions are easily obtained, proves useful from an acoustical-engineering point of view.
Effect of Noise on an “Intellectual” Task
Authors: Broadbent D. E.
Published: September 2005

Three groups of Naval Ratings worked for two sessions each at a subtraction task involving a considerable immediate memory load. One group had both sessions in relative quiet (70 db), a second had the first session in 100 db noise and the second in quiet, and the third group had noise and quiet in the reverse order.

In the first session the noise group slowed down at solving the subtractions as time went on, relative to the groups working in quiet. A similar difference appeared in the second session, but, in addition, there was an aftereffect of noise such that the subjects who had had noise previously slowed down relative to those who had not.

Slowing down of performance with time was in all groups most marked in extroverts.

These results suggest firstly that intellectual work as well as simple sensory tasks must be regarded as endangered by noise. Secondly, there may be harmful aftereffects from noise, but it is not clear whether these will appear in any situation or only in one similar to that in which the noise was experienced.
Distortion of Underwater Acoustic Signals Reflected from a Time and Space Random Surface
Authors: D'Antonio R. A. , Hill R. F.
Published: September 2005

A portion of the general underwater-acoustics communication problem—namely, the communication channel defined as the path from a transmitter to a receiver via a single reflection from a surface that is random in space and time—is investigated. The experimental observation of this channel utilizes a model tank with a wind-driven random surface. Continuous-wave (CW) and narrow-band noise-modulated signals are transmitted and the amplitude of the water surface at the point of reflection, the envelope of the transmitted signal, and the envelope of the received signal are observed. Probability density functions, auto- and cross-correlation functions, and power-spectral-density functions are obtained for the observed signals. A simple theory of specular scattering is developed and is found to compare well with the experimental results. Results of particular interest are (a) for CW transmission, the envelope of the received signal has a bandwidth greater than the bandwidth of the surface amplitude; (b) crosscorrelations observed between envelopes of amplitude-modulated transmission signals and envelopes of the received signals are low but finite; and (c) there is no correlation between the surface amplitude and the envelope of the received signal.
Acoustic Radiation from a Thin Torus, with Application to the Free-Flooding Ring Transducer
Authors: Sherman Charles H. , Parke N. G.
Published: September 2005

The toroidal wavefunctions developed by V. H. Weston [Quart. Appl. Math. 16, 237–257 (1958)] are used to solve the problem of acoustic radiation from a thin torus, and some of the technical difficulties associated with more-general toroid problems are briefly discussed. The thin-torus solution is worked out in complete detail for a normal velocity on the torus that approximates the motion of the free-flooding ring transducers that are commonly used in underwater sound applications. Comparison of the calculated results with measurements shows that the thin torus is a useful theoretical model for farfield radiation from ring transducers, but better models are needed for a more complete description of the sound field.
Changes in the Simultaneous Masked Threshold of Brief Tones
Authors: Elliott Lois L.
Published: September 2005

Simultaneous monotic masking of a 5- or 10-msec, 1000-cps signal by bursts of wide-band noise of 30–1000 msec duration (70 dB SPL) changes and is dependent upon delay of the tone (Δt) relative to masker onset. The elevated masking of the tone at short Δt's (overshoot) is independent of masker duration, while minimum masking occurs at delay times of 200 or 300 msec. A 500-msec-long, 400-cps noise band centered at 2550 cps produces little overshoot for 10-msec tonal signals with frequencies located within the band but considerable overshoot for frequencies just outside it. This occurs also for a 200-cps band centered at 1270 cps but not for a 100-cps band at 250 cps. These effects were observed for dichotic masking also. For 500-msec bursts of wide-band masking noise, greater overshoot occurs at higher signal frequencies than at lower. Several different psychophysical procedures produced similar results.
Fluctuations of Scattered Noise
Authors: Mittenthal Lothrop
Published: September 2005

The coefficient of variation of scattered sound is shown to be a decreasing function of number of frequency components. The limit is found and the distribution of the rms value of scattered narrow band random noise is shown to be a Dirac delta function.
Parameter of Nonlinearity in Fluids. II
Authors: Coppens A. B. , Beyer Robert T. , Seiden M. B. , Donohue James , Guepin Frans , Hodson Richard H. , Townsend Charles
Published: September 2005

The sound velocity has been measured as a function of temperature and hydrostatic pressure for a number of organic liquids and for water-methanol mixtures. These data have been used to compute the ratio B/A of the coefficient B of the quadratic term to that of the linear term A in the adiabatic expansion of pressure changes in terms of density changes. The ratio has also been computed (by use of data from other sources) for sea water and for five alcohols. A discussion is given of various methods of computing B/A.
Vibrational Relaxation in Carbon Dioxide/Water-Vapor Mixtures
Authors: Lewis James w. L. , Lee K. P.
Published: September 2005

Sound-absorption and -velocity measurements in carbon dioxide water-vapor mixtures have been made over the temperature range 23°–195°C. The measurements were made using plane progressive waves inside glass tube 1.73 cm in diameter. Values of the mixture relaxation time τ (AB) obtained from the data increase from 0.27× 10−8 sec at 23°C to 0.58× 10−8 sec at 195°C, displaying no minimum value as has been reported previously by other authors. The collision efficiency decreases slightly over this temperature range. Values of an average collision diameter calculated from the experimental data are in good agreement with values predicted by the Widom-Bauer theory, the basis of which is a chemical affinity between the CO2 and H2O molecules.
Chlorine-Release Test for Cavitation-Activity Measurements
Authors: Liu Shih-Ping
Published: September 2005

A new method is described for measuring the cavitation activity in an ultrasonic cleaning system. The method is based on the sonochemical liberation of chlorine from carbon tetrachloride dissolved in water. The chlorine release rate is found to be rapid and linear with irradiation time. The method is used to measure the effect on chlorine release rate of variables such as power input to the transducer, water height, water temperature, and concentration of surfactant in water. The method is also evaluated against the removal of graphite from alumina-ceramic rings. The result indicates that the chlorine-release rate has a quantitative relationship with cleaning efficiency. A further comparison of the method and an actual soil-removal process indicates that a quantitative relationship exists between the chlorine-release rate and cleaning capability at a given frequency.
Stability of Forced Oscillations of a Vibrating String
Authors: Miles John W.
Published: September 2005

The nonlinear response of a stretched string to a transverse, harmonic excitation in the spectral neighborhood of the first natural mode is considered. Approximate, two-degree-of-freedom solutions of the equations of motion are determined by retaining terms of first and third order in the amplitude of the motion and by retaining only the dominant terms in the Fourier-series representations of the transverse motions in perpendicular planes. Let ω be the forcing frequency. It is found that (a) planar harmonic motion is unstable over a finite frequency interval, say ω1 < ω < ω2, just above the natural frequency; (b) nonplanar harmonic motion is stable for ω1 < ω < ω3, where ω3 > ω2 for sufficiently small damping; (c) the energy associated with the transition from stable planar motion to stable nonplanar motion vanishes at ω = ω1 but is positive for ω1 < ω < ω3. It is predicted that the lower transition between planar and nonplanar motion should occur at ω1 as ω either increases or decreases through ω1, but that the upper transition between nonplanar and planar motion should tend to occur at ω3 for increasing ω and at ω2 for decreasing ω. The effects of additional degrees of freedom, corresponding to higher modes in the Fourier series representation of the motion, are considered in Appendix A.
Masking-Level Differences as a Function of Interaural Disparities in Intensity of Signal and of Noise
Authors: Egan James P.
Published: September 2005

A marked release from masking, or masking-level difference (MLD), results when a monaural signal is presented with perfectly correlated (in-phase) binaural noise, N0—Sm, rather than with monaural noise, Nm—Sm. When the noise in the nonsignal ear is introduced at a lower level than that in the signal ear, a smaller MLD results. In one experiment, MLD's were determined as a function of the intensity of the noise in the nonsignal ear with the interaural conditions of N0, Nπ, and NU as parameters; for N0, there is some release from masking even when the noise in the nonsignal ear is as much as 40 dB down from that in the signal ear. The following considerations led to a second experiment. A release from masking results when a sinusoid is presented monaurally Sm rather than binaurally and in phase S0 with perfectly correlated noise N0. With N0-S0, when the sinusoid in one ear is reduced in intensity, rather than being removed entirely, a smaller MLD than for N0-Sm should result. Therefore, MLD's were determined as a function of the ratio of the energies of the left- and right-ear sinusoids with correlated noise N0. In all experiments, the signal (500 cps, 0.25 sec) was presented to the listener in one or the other of two temporal intervals, against a background of white noise. Psychometric functions were determined for each condition, and MLD's were estimated from these functions.
Propagation of Low-Frequency CW Sound Signals in the Deep Ocean
Authors: Guthrie Albert N. , Shaffer John D.
Published: September 2005

The acoustic pressure field of a low-frequency CW source, towed at slow speed at a depth of 25 m, was measured as a function of range by a stationary hydrophone 460 m below the surface for ranges between 64 to 122 km. Frequencies of 10.04 and 13.89 cps were used. Reversed radial runs were made to test range dependence and repeatability of modal-interference patterns that were observed in previous experiments. Range dependence and repeatability of the patterns were verified for both frequencies, and a computed theoretical curve for 10.04 cps over a limited range interval closely resembled an experimental curve consisting of an average of three separate runs made over that range interval.
Analysis of Sea Water from the Tongue of the Ocean
Authors: Konrad W. L.
Published: September 2005

The chemical analysis of sea water sampled in the Tongue of the Ocean is presented as a function of depth. Water temperature and sound velocity are also tabulated for each depth. The results are quite typical of the Caribbean, with the exception of somewhat larger percentages of bicarbonate and calcium ions.
Coarticulation in VCV Utterances: Spectrographic Measurements
Authors: Öhman S. E. G.
Published: September 2005

In this paper, the formant transitions in vowel + stop consonant + vowel utterances spoken by Swedish, American, and Russian talkers are studied spectrographically. The data suggest a physiological model in terms of which the VCV articulations are represented by a basic diphthongal gesture with an independent stop-consonant gesture superimposed on its transitional portion. This interpretation necessitates reevaluation of the locus theory proposed by the workers of the Haskins Laboratories. Some conclusions about the general nature of the neural instructions behind the VCV gestures are discussed.
Ultrasonic Studies of Molecular Association in Aqueous Solutions of Formic, Acetic, Propionic, and n-Butyric Acids
Authors: Stumpf F. B. , Crum L. A.
Published: September 2005

The absorption of ultrasound at 19 Mc/sec is studied as a function of concentration in aqueous solutions of formic, acetic, propionic, and n-butyric acids. Peaks in the absorption-versus-concentration curves give the association ratios. The bonding mechanism responsible for the association is suggested.
Axisymmetric, Plane-Strain Dynamic Response of a Thick Orthotropic Shell
Authors: Klosner Jerome M. , Dym Clive L.
Published: September 2005

The plane-strain, axisymmetric, thickness-stretch modes of thick, isotropic and orthotropic elastic shells embedded in a thin elastic casing are investigated. The steady-state dynamic response of their viscoelastic counterparts is obtained and compared with the response of the elastic shells. Use is made a of a higher-order shell theory and its accuracy for the lower modes is demonstrated. Finally, the effect of orthotropy on the rapidity of the transition from the free vibrations of a plate to that of a solid elastic circular cylinder is investigated.
End Point of Lateralization for Dichotic Clicks
Authors: Babkoff Harvey , Sutton Samuel
Published: September 2005

A series of experiments was undertaken to systematically study one aspect of binaural interaction for dichotically presented clicks—the end point of lateralization, which is referred to in this paper as the lag-click threshold (Δt2). The results of experiments in which click parameters were manipulated are presented in Sec. III. These results indicate that the lag-click threshold is decreased by an increase in the sensation level (SL) of both clicks, by an interaural intensity asymmetry favoring the lag crick, or by a decrease in the low-frequency components of both clicks. The results of experiments in which the background-noise parameters were manipulated appear in Sec. IV. As the SL of binaural broad-band noise (125–8000 cps) is increased to 30 dB, the lag-click threshold decreases; but as the noise level is increased further, the lag-click threshold increases. The finding of a minimum point at 30 dB is related to the broad spectrum of the noise. One-octave bandwidths of noise produce monotonic functions. A 1-oct low-frequency band of noise presented either to both ears or to the ear receiving the lead crick, decreases the lag-click threshold, while a 1-oct high-frequency band of noise presented either to both ears or to the ear receiving the lead click increases the lag-click threshold. Finally, a 1-oct low-frequency or high-frequency band of noise presented to the ear receiving the lag click produces a substantial increase in the lag-click threshold. The results are discussed briefly in terms of the available physiological literature and a model is proposed.
Ultrasonic Attenuation and Relaxation Times in Water Vapor and Heavy-Water Vapor
Authors: Yamada Kazunari , Fujii Yahei
Published: September 2005

Ultrasonic attenuation in water vapor and heavy-water vapor has been measured over the range of angular frequency/pressure from 10 to several hundred radian megacycles per second/atmosphere about 137°C. The resulting vibrational relaxation time at 1 atm for H2O vapor comes out to be about (8±2.5) × 10−9 sec and that in D2O vapor to be about (7.0±1.0) × 10−9 sec.
Noise Covariance and Vertical Directivity in a Deep Ocean
Authors: Liggett W. S. , Jacobson M. J.
Published: September 2005

Under the assumption that deep-water ocean noise is a superposition of uncorrelated plane waves, the covariance can be expressed in terms of the noise directivity. We propose a simple directivity function that agrees with experimental results and use it to study the covariance for the case of vertical receiving points. We investigate covariance versus spacing for zero time delay and various directivities and bandwidths. When almost all of the noise arrives from the horizontal, the zero-delay covariance is always positive; when most of the noise arrives from overhead, it is negative for some spacings. We present contours of constant covariance as a function of spacing and time delay for various directivities and a narrow frequency band. We also examine covariance for single-frequency noise. Vertical noise with steering towards the vertical and horizontal noise with steering towards the horizontal are found to give the same covariance values. We examine maximum covariance over time delay and also that delay for which maximum covariance occurs. Numerous comparisons are made between our predictions and published experimental results. Finally, covariance for horizontal receiving points is considered.
Monostatic Reflection from Rigid Objects Defined by Quadric Surfaces
Authors: Rudgers Anthony J.
Published: September 2005

By applying theory of acoustic reflection applicable in the far field and embodying the Kirchhoff approximation, a formula is derived that may be used to calculate the velocity potential reflected monostatically from any rigid, nonconcave object that can be defined by a quadric surface. By substituting appropriate geometrical constants into this formula, it may be used to calculate the velocity potential reflected from such objects as: (1) the ellipsoid and its special cases, the sphere and the prolate and oblate spheroids, (2) the limited paraboloid and the limited hyperboloid, both of elliptical cross section, (3) the cone of elliptical cross section. The formula also allows the calculation of the velocity potential reflected from the segment or the frustum portion of any of the above objects. The formula is restricted to orientations of the reflecting object such that the intersection of the object's two planes of symmetry coincides with the monostatic axis.
Direct-Recording Frequency and Amplitude Meter for Analysis of Musical and Other Sonic Waveforms
Authors: Tove P. A. , Norman B. , Isaksson L. , Czekajewski J.
Published: September 2005

The notation of frequency and time relations in the study of musical phenomena produced by single unisonous instruments or song is discussed. The nature of the pertaining electrical waveforms in recorded music of this type, and especially the possibilities of extracting the fundamental and measuring and recording its frequency (pitch), is treated. A transistorized instrument performing this function and having fast response to changes in frequency is described. The output from this meter is fed to a fast ink recorder to show the frequency variations on a convenient diagram as an objective form of music printing, or “visible music.” As a complement, the original waveform is rectified and plotted logarithmically in a second channel on the recorder to show the amplitude variation. The frequency compass covered in a single registration is normally a single octave, which can start at any consecutive minor-third interval (frequency ratio 6/5) in the range A1 (55 cps) to A6 (1760 cps). Changes with time can be recorded with a detail down to about 0.01 sec, and frequency differences of a small fraction of a half-tone can be measured. The dynamic range of the registration of amplitude is ≈40 dB. A third trace on the recorder is a 50-cps waveform used for time marking. The frequency and amplitude levels of the registration can be checked with a calibrator. This is a self-stepping oscillator giving 7 tones, each of 1 sec duration and separated by whole-tone intervals. Thus, it covers one octave and this can be chosen to start at 55, 110, ⋯ or 1760 cps. The amplitude calibration is logarithmical with manually chosen levels.
Study of Twenty-Six Intervocalic Consonants as Spoken and Recognized by Four Language Groups
Authors: Singh Sadanand , Black John W.
Published: September 2005

Twenty-six intervocalic consonants were recorded by three speakers of each of four languages—Hindi, English, Arabic, and Japanese—and heard by 24 speakers of each of them. The data were treated in two ways. (1) An analysis of variance indicated that listening groups differed and that consonants were unequal in their intelligibility and showed statistically significant interactions between speakers and consonants, between listeners and consonants, and among consonants, listeners, and speakers. All speakers spoke better and all listeners listened better when saying and hearing sounds of their native language. (2) A quantitative procedure employed by Miller and Nicely was adapted to ascertain which features were retained by the listeners in their error responses and whether or not these were similar from one language group to another. All consonants were classified in a binary manner in relation to each of seven channels into which the voice communication network was subdivided. The unusual outcome lay in the ranks of the seven channels in terms of the extents to which they were correctly preserved in the responses. A single rank order in this regard was duplicated for all the listening groups: (1) nasality, (2) place, (3) liquid, (4) voicing, (5) duration, (6) friction, and (7) aspiration.
Distinctive Features and Errors in Short-Term Memory for English Consonants
Authors: Wickelgren Wayne A.
Published: September 2005

Errors in short-term recall of 23 English consonants were tabulated and related to three distinctive-feature systems. The consonants were always presented in initial position in a consonant-vowel diagram, and the vowel was always /a/. Subjects were instructed to copy a list of consonants as it was being presented, followed by recall of the list. Perceptual errors were excluded from the recall-error matrix by scoring for recall only correctly copied consonants. The data were also analyzed in such a way as to eliminate differences in response bias for different consonants. Having controlled for response bias, each feature system makes predictions about the rank order of different intrusion errors in recall. Each of the three feature systems was significantly more accurate than chance in these predictions, but the most accurate system was one developed in the present study. This system is a slightly modified version of the conventional phonetic analysis of consonants in terms of voicing, nasality, openness of the vocal tract (manner of articulation), and place of articulation. The results suggest that a consonant is coded in short-term memory, not as a unit, but as a set of distinctive features, each of which may be forgotten at least semiindependently.
Measurements on the Impulsive Noise from Crackers and Toy Firearms
Authors: Gjaevenes Kjell
Published: September 2005

The possibility of permanent hearing losses originating from the impulsive noise of crackers and toy firearms is discussed, regarding the results of performed measurements. These results support the assumption of the occurrence of such hearing losses.
Effect of External or Internal Static Pressure on the Natural Frequencies of Unstiffened, Cross-Stiffened, and Sandwich Cylindrical Shells
Authors: Greenspon Joshua E.
Published: September 2005

A general formula is given for the natural frequency of a pressurized shell that is loaded with static load on its cylindrical surface as well as along its edge. It is found that the natural frequency of the pressurized shell Can be written in terms of the natural frequency of the unpressurized shell. The connection between natural frequencies and buckling load is discussed.
Earcanal Pressure Generated by a Free Sound Field
Authors: Shaw E. A. G.
Published: September 2005

The pressure levels generated at the entrance to the earcanal by progressive waves from a point source at a distance of 1 m have been measured for a group of ten subjects. Individual curves are presented for all ten subjects at six azimuthal angles of incidence. Measurements at 0°, 45°, 90°, and 180° cover the frequency range 0.2–14 kcps. Measurements at 270° and 315° extend to 8 kcps. The average earcanal-versus-free-field pressure levels are in good agreement with Wiener's data over the common frequency range. Certain features (maxima at 2.4 and 13 kcps, minima at 4 and 10 kcps) appear to be relatively independent of angle of incidence. Others (peak at 7 kcps) have strong azimuthal dependence. Normal modes of the concha may have an important role in the 6- to 10-kcps region.
Earcanal Pressure Generated by Circumaural and Supraaural Earphones
Authors: Shaw E. A. G.
Published: September 2005

The hearing thresholds of four subjects have been measured at nine audiometric frequencies from 0.125 to 8 kcps with a probe microphone placed in the external ear. The probe-tube pressures at hearing threshold are found to be substantially the same with the four different earphones used to generate the tone. The earcanal response curves of three circumaural and two supraaural earphones coupled with a group of ten subjects have been measured over a 0.2- to 15-kcps frequency range. The groups of curves have been normalized with respect to reference response curves obtained with suitable couplers. The five groups of earphone response curves are found to have much in common with one another and with curves of earcanal pressure generated by a free sound field, using the same group of subjects; there are also significant differences. The relationships are thought to shed much light on the acoustic behavior of earphone systems. Average response curves for the five earphones permit the transfer of coupler pressure at hearing threshold; data for TDH39/MX41AR and HA10 earphones are in good agreement with published subjective data. Intra-subject range (average range of pressure with repeated measurements on a single subject) varies from 0.2 to 10 dB, depending on earphone type and frequency. In conclusion, it is suggested that existing earphone systems, though well-adapted for speech communication, may not provide ideal coupling for more-exacting applications.
Conical Refraction of Transverse Ultrasonic Waves in Quartz
Authors: McSkimin H. J. , Bond W. L.
Published: September 2005

Experimental results are presented for the directions of energy flow for transverse ultrasonic waves propagated along and near the Z axis of quartz. Measurements made with an absorption-probing technique as a function of frequency in the range 12–360 Mc/sec demonstrate the considerable variations in the spread of energy for slightly off-axis propagation. The use of plane-wave “Christoffel” solutions to obtain a qualitative picture of conical refraction is discussed in some detail. In general, the features of Waterman's analysis are confirmed [P. C. Waterman, Phys. Rev. 113, 1240–1253 (1959)].
Ultrasonic Atomization Studies
Authors: Fogler H. Scott , Timmerhaus Klaus D.
Published: September 2005

Atomization of selected fluids has been observed to occur in a capillary at various resonance heights of the standing ultrasonic wave in the fluid. The length of fogging has been observed to be a function of the voltage applied to the transducer producing the ultrasonic wave in the fluid. A theoretical analysis is given to explain the experimental results obtained.
Vibration of a Tight Cable Containing a Turnbuckle
Authors: Ehlers F. Edward
Published: September 2005

The partial differential equations for the vibration of a cable containing a turnbuckle are solved by the method of separation of variables. Since the turnbuckle introduces inhomogeneous boundary conditions, the eigenfunctions are not orthogonal in the classical sense, and a special scalar product must be defined to make the eigenfunctions orthogonal. By means of this scalar product, eigenfunction expansions for the initial conditions of velocity and displacement were found. The results simplify considerably when the turnbuckle is located in the center of the cable. The eigenvalues divide naturally into two distinct sets corresponding to pure rotation and to pure lateral displacement of the turnbuckle and yield asymmetric and symmetric vibration of the cable, respectively. As the mode number becomes infinite, the eigenvalues approach those corresponding to each half of the cable with the turnbuckle held rigid. In the turnbuckle located at one end, the solution becomes identical in form to the pure rotation terms in the expansions for the turnbuckle in the center of the cable.