bluuebunny/crossref_metadata_2025 huggingface dataset:
Perception of dichotic chords by hemispherectomized subjects
Authors: Elton H. , Dennis M. , Bogen J. E. , Yund E. W.
Published: October 2005

The phenomenon of ear dominance for the pitch of dichotically presented tones has been described in previous publications [Efron and Yund, Neuro-psychologia 12, 249–256 (1974); 13, 137–150 (1975); 13, 151–161 (1975); Brain and Language 3, 246–254 (1976); J. Acoust. Soc. Am. 59, 889–898 (1976)]. In these studies on more than 100 normal subjects, the pitch mixture of the perceived dichotic chord was strongly dominated by the frequency presented to the right ear in 10% and by the left ear frequency in another 10%. The remaining subjects (80%) had either a weak or a nonsignificant ear dominance. Subsequent studies on subjects with forebrain commissurotomy [J. Acoust. Soc. Am. 59, S53(A) (1976)] indicated that the pitch minute of the dichotic chord was determined by a functional asymmetry in a subcortical pitch processor. The present study with three subjects hemispherectomized in infancy and one at age 13 reveal a strong ear dominance for the ear contralateral to the existing hemisphere in all four subjects. These results suggest that there is efferent control, from the cerebral cortex, on the hypothesized subcortical pitch processor.
Impact sound level contour analysis of industrial sites
Authors: Bradley W. E. , Strong W. F. , DiBlasi F. T. , Hood J. M.
Published: October 2005

The evaluation of industrial sites, such as for nuclear or fossil power stations, often requires detailed analysis of the existing sound levels and acoustic impact of the proposed facility at each site. Such a study was performed for five potential power station sites according to the guidelines set forth by a state licensing agency with extensive site study requirements. As required by the state, ambient sound level contours, plant construction, operation and maintenance contours, and sound level impact contours were prepared for each site for the 12 required sampling periods. A variety of land uses ranging from rural to industrial-urban were included in the study. This paper summarized the techniques involved in developing and analyzing the contouring process to the various acoustic environments.
Vibration damper for circular saws
Authors: Allen C. H.
Published: October 2005

A new type of vibration damper for circular saws has been demonstrated by a preliminary working model that is applicable to conventional blades without decreasing the depth of cut. Early data show that the ringing, which usually lasts several seconds after an impact, dropped off in a fraction of a second, and the noise peak was reduced more than 10 dB; as measured with the “fast” response of a sound level meter. The first operation of the damper while cutting a pine board (using a temporary arrangement) gave a 5-dB reduction, When a proper installation is made, the noise for the sawing operation is expected to be reduced as much as that for an impact. This paper will discuss the design and application of this new development and will present data from experiments now in progress.
Prediction of sound pressure levels in irregularly shaped factory spaces
Authors: Zinskie J. H. , Mitchell L. D. , Hurst C. J.
Published: October 2005

The prediction of sound pressure levels in irregularly shaped factory spaces is approached through an analysis of acoustically coupled rooms. Previous work has indicated that room surface sound absorption characteristics create a theoretical interdependence between the sound pressure fields in each coupled volume. Whenever a barrier is interposed between a sound source and observer, the effects of diffraction must also be considered. A computer algorithm was developed to predict sound pressure levels in irregularly shaped rooms using a modified statistical acoustic theory. The program is based on a conversational technique and requires the user to enter information regarding room geometry, surface absorptions, receiver placements, and source sound power and placement information. Several output options are provided, among which is a plan view print-plot of sound pressure level contours in the analysis room. [Work supported by NSF.]
First-order torques and spin velocities of solid bodies in intense sound fields
Authors: Wang T. G. , Kanber H. , Rudnick I.
Published: October 2005

Time-average forces, torques, and velocities in sound fields have always been associated with second- or higher-order effects. We've identified, for the first time so far as we know, phenomena which are first order in the acoustic particle velocity. In a rectangular box of square section the (1,0,0) and (0,1,0) modes are degenerate and when equally excited the particle motion is in general elliptical; it is circular if the phase difference of the modes is 12π and this is the case we'll have in mind. A long, small diameter, solid cylinder with its axis normal to the square cross section and at its center is then surrounded by a fluid whose particles are undergoing rotational motion (neglecting the scattering field of the cylinder). The cylinder experiences a torque due to viscosity and will rotate if free to do so. Moreover if the particle displacement is significantly greater than the viscous penetration depth the torque and velocity of rotation will be first order in the particle velocity. Measurements made on a one inch cylinder suspended by a wire, and in free rotation, in a 1.6 kHz sound field, which support these conclusions, will be presented.
Elastic wave scattering from ellipsoidal cavities
Authors: Tittmann B. R.
Published: October 2005

Experimental results have been compared with theory for ellipsoidal and spherical cavities embedded in titanium alloy by the diffusion bonding process. The measurements comprised the cases of incident longitudinal and shear waves, including mode conversion. Whenever possible, comparisons were performed with the results of exact theory and those of the Born approximation. The Born approximation was found useful in the back scattering directions for low ka values (k is the wave vector of the sound wave and a is the radius of the scatterer). In the experiments, a reciprocity relation was discovered: The same angular dependence is obtained in mode conversion when the mode of the incident and scattered wave is interchanged. This result has now been corroborated by both the exact theory and the Born approximation. [This work was partially supported by ARPA-AFML Contract No. F33615-74-C-5180.]
Reflection of waves by a cylindrical cavity in an absorptive medium
Authors: Flax L. , Neubauer W. G.
Published: October 2005

Previous calculations of elastic wave reflections by cavities in solid materials have not included the effects of wave attenuation even for materials known to exhibit significant losses. Calculation without losses indicate the asymptotic approach of the scattering to a limiting value at some ka. The inclusion of losses modifies this behavior. Cases will be shown for reflections below ka = 10 and for materials with small and large losses.
Seasonal variations in volume scattering strength levels
Authors: Anderson W. B.
Published: October 2005

Volume reverberation measurements have been conducted in the Straits of Georgia (49. 317N, 124W) over a two-year period. Data were acquired with a downward-looking sonar system operating at discrete frequencies over a two-octave band (f0 = 35 kHz). Supporting zooplankton samples were acquired with a fine-mesh plankton net trawled vertically through the water column under test. Acoustic data shows considerable variation in volume scattering strength (Sv) levels to exist between seasons, generally supported by biological samples. In the fall/winter season a definite downward vertical migration of acoustic scatterers is observed to begin at sunrise. A similar upward migration is observed at sunset. During the day the upper 100 m of the water column is essentially void of acoustic scatterers with a significant increase observed between 100 and 200 m. The migrating scatterers begin from and return to this stratum. Review of calculated Sv levels acquired during that seasonal time period indicate no variation of level as a function of frequency over the test spectrum. During the spring/summer season the upper 100 m show an increase in Sv levels and caught zooplankton. The vertical migration, while still evident, is not the dominate phenomenon. Acoustic data shows the calculated Sv levels to have a noted increase as a function of increasing frequency. This phenomenon appears restricted to the upper 200 m.
Goniometric measurement of power scattered from wind driven water surfaces
Authors: Zornig J. G.
Published: October 2005

A recently constructed 11-ft, 3-axis, semiautomatic underwater goniometer has made possible precision measurement of acoustic power scattered from the statistically stationary wind driven water surface at Yale. Measurements have been made over 180° of azimuth and at several grazing angles. These measurements have been corrected for beam patterns and pulse shape to give a scattering cross section for the surfaces and geometries studied. The results of these measurements indicate that current mathematical models of the scattering process are not able to predict spatial distribution of scattered power in all cases.
Range dependence of underwater echo from random rough surfaces
Authors: Mikeska E. E. , McKinney C. M.
Published: October 2005

The spreading-loss portion of the total propagation loss of sound reflected or scattered from a rough ocean bottom is not firmly established in the literature. Many investigators of bottom backscattering assume, for non-normal incidence, spherical spreading both from the source to the bottom and for the return path; this procedure yields a spreading-loss correction term of −40 logR (where R is the one-way range in yards). At normal incidence, the mirror-image solution is generally assumed for bottoms which are not too rough relative to the wavelength, resulting in a spreading loss term of −20 log (2R). To clarify the actual range dependence of the returning echo, experimental measurements were made in a laboratory tank on the echo from randomly rough model surfaces having known statistical properties. Data are available for normal incidence at 100 kHz. The echo from a plane surface was checked and confirmed to result in mirror-image behavior, with a spreading loss of 6 dB over the return path. The echo from a random rough surface having surface irregularities comparable to a wavelength fluctuated greatly with range and with small changes in the particular area of surface insonified, but an average of many range dependence curves shows an echo-amplitude decay rate of 13.5 dB for a tenfold increase in range, beginning about 2 ft from the reflecting surface.
Acoustic reflection from sea bottom with linearly increasing sound speed
Authors: Williams A. O. , MacAyeal Douglas R.
Published: October 2005

We calculate the acoustic reflection coefficient for plane waves, in a homogeneous fluid half space, incident at arbitrary angle upon an underlying half space of bottom sediments. The latter, treated here as a fluid of constant density, has a sound speed c increasing with depth z, dc/dz being constant (a behavior frequently encountered). An exact formal expression is found for the complex reflection coefficient R, in terms of a modified Bessel function. With no absorption, |R| is unity for all angles, as expected from ray theory. Assuming bottom absorption, we derive an analytic approximation for R, valid at low acoustic frequencies (up to a few kilohertz, at least). Numerical results are described. Incident angles too near the normal must be excluded, but a different approximation serves for small angles, including normal incidence. A more realistic model having layers in the upper part of the bottom is examined. In effect, it now reduces to problems already solved. [Supported by Naval Electronics Systems Command, Department of the Navy, Washington, DC, under Contract N00039-76-C-0081.]
Ocean sub-bottom refraction. A significant propagation mechanism at low frequencies
Authors: Dullea R. K. , Herstein P. D. , Santaniello S. R.
Published: October 2005

Experimental studies by independent investigators have indicated that low-frequency acoustic propagation can be affected by ocean-bottom refracted energy. However, the total energy returned from the bottom is also composed of water-sediment interface and sub-bottom reflected energy and it is often times difficult to determine the significance of the sub-bottom refracted energy. Deconvolution processing techniques applied to wide-band explosive-source experimental data have aided in time-isolation of the various bottom-interacted arrivals so that signal travel times could be determined. With the use of a ray-tracing model which incorporated a sediment sound-speed gradient, accurate identification of sub-bottom refracted arrivals has been achieved. Spectral analyses of these data have further revealed that sub-bottom refracted energy can exceed reflected energy by as much as 5–10 dB at frequencies below 500 Hz. This effect has been observed for diverse geographical areas of the North Atlantic (shallow basins, abyssal plains) where sediment structures vary considerably. As a consequence, acoustic properties of the ocean bottom cannot be correctly inferred at low frequencies by a Rayleigh reflectivity model. [Work supported by NAVSEA.]
Vibration induced masking noise
Authors: McGregor Howard N.
Published: October 2005

Very high acoustical gradients negate acoustical privacy in buildings which normally have acceptable transmission loss between units. This is particularly true of mountain condominium complexes which have entertainment areas in the same building. The vibro-mask system reduces the acoustic gradient by introducing masking noise into the quieter areas such as sleeping quarters. Acoustical transducers induce structural vibration which is in turn transmitted throughout the building with a reasonable degree of uniformity. Equalization of the input power spectrum is accomplished by electronic networks to obtain the desired masking sound spectrum.
System for the measurement of acoustic energy density
Authors: Morton Bruce L. , Hixson Elmer L.
Published: October 2005

In the reverberation chamber method of measuring the sound power radiated from an acoustic noise source, pressure microphones are used in arrays, traversed over fixed paths or used singly with a rotating diffuser. The purpose is to accurately measure the potential energy density in the sound field produced by the noise source. In general, accuracy is limited by the variance in the measurement of the potential energy density. When the total energy density (potential and kinetic) is measured, the variance should be cut in half. A system has been designed and built that measures the total energy density in a three-dimensional sound field. Three sets of spaced pressure microphones are placed orthogonally. For a set the signals are averaged and squared to produce the potential energy at a point and the difference signal is squared to give the square of one component of the acoustic velocity vector. By multiplexing the sum of the squares of the three components of the velocity vector the kinetic energy is produced. The three pressure squared signals are averaged to produce the potential energy, halved and added to half the kinetic energy to give total energy density. Calibration is accomplished with an acoustic calibrator or pistonphone and small plane wave tube. Measurements made in one dimensional and three dimensional sound fields will be presented.
Test report of Westinghouse LB 16 low-frequency flexural disk transducer at NUC Calibration Facility, Lake Pend O'Reille, Idaho
Authors: Nichols C. S. , Tighe F.
Published: October 2005

Flexural disk transducers are used as underwater sources for low-frequency sound. The large displacements needed for low-frequency sound generation requires that the backing material for the radiating disks be very compliant. The radiating disks are quite compliant and are susceptible to breakage when a pressure differential exists between the radiating face and the backing face of the disks. Hence for underwater applications flexural disks are usually pressure compensated to keep the pressure in the backing material equal to the ambient hydrostatic pressure. a passive pressure compensation system has been developed and incorporated into a 16-in.-diam. double-trilaminar flexural disk. The transducer system has been tested at Lake Pend O'Reille, Idaho, by Naval Undersea Center and Westinghouse Electric Corporation.
Design of high-efficiency transducer elements and arrays
Authors: Widener M. W.
Published: October 2005

Parametric sound reception has created a need for pump transducers capable of continuous operation with intense sound fields. Reduction of internal losses and improved heat transfer become important design goals. A transducer structure has been developed in which the internal mechanical energy dissipation is reduced dramatically and the thermal coupling of the ceramic to the water is improved. The basic design consists of a quarter-wavelength mass directly immersed in the fluid medium with the ceramic element surrounded by an air cavity and driven in quarter-wavelength resonance. The assembly is suspended at the vibrational node by a metal flange formed integrally with the radiating mass. The resonant Q of the unloaded assembly in air can be as high as 300–400. Water loading diminishes the circuit Q to the order to 5–15 which corresponds to an effective electrical-to-acoustic energy conversion efficiency in the range of 85–98%. Practical elements exhibiting the same general quality of operation have been constructed over the frequency range from 7 to 400 kHz. [This research was supported by the Advanced Research Projects Agency of the Department of Defense and was monitored by the Naval Electronic Systems Command under Contract N00039-76-C-0231.]
Options and techniques for shock hardening of ship's equipment
Authors: Mains Robert M.
Published: October 2005

The problem of shock hardening ship's equipment is discussed from initial planning and strategy development through final action decision after design, analysis, and test. The planning operation is the one in which performance criteria are established, the design is anticipated, the analysis is laid out, and the designer is given a means for developing a preliminary design. With the preliminary design in hand, the static structural calculations are performed and the mass and stiffness matrices are assembled. With the normal modes and frequencies from an eigenvalue run, the system displacement responses to step-velocity shock are obtained. These responses can be converted to member forces and stresses or accelerations. The results are evaluated against the performance criteria, and the whole process is reexamined for validity before action decisions are made.
Hearing damage from forest firefighting operations
Authors: Harrison R. T. , Chaney R. B.
Published: October 2005

Audiological examination of Forest Service “Helitack” personnel (firefighters who are transported directly from their base to the fire scene by helicopters) reveals that a large percentage of them show significant hearing loss characteristic of noise-induced PTS. There are indications that this PTS is correlated with length of service on helicopters. However, measurements of the helicopter noise environment and of normally encountered exposure times indicate that OSHA noise exposure criteria are not exceeded. Also, for a limited sample of normal hearing helitack personnel, no TTS was observed after a 40-min flight. Two possible explanations for the unexpectedly high incidence of PTS are discussed in this paper. The first is that activities other than helicopter operations cause the PTS. This is investigated by means of a noise-history questionnaire. The second is that OSHA criteria are not stringent enough for these particular operations. Finally, the program that the Forest Service is implementing for helitack crews is briefly discussed.
Influence of echo-carrier-frequencies and antenna-dimensions on the performance of echosonde antennas
Authors: Adekola S. Adeniyi
Published: October 2005

Accurate computer-simulations of echosonde antennas can contribute toward (1) better understanding of acoustic remote sensing of atmospheric structure/properties and (2) time-saving and avoidance of unforeseen problems in fieldwork. However, computer-predicted patterns are at odds with measurements, particularly regarding phase variations across transmitting antenna apertures. The rapidly changing phase variations of previous computer simulations do not compare well with nearuniform phase of measurements. Modifications of antenna design which improve antenna-system performance, are considered. These are based on the results of a general antenna-integral-formulation [Adekola, J. Acoust. Soc. Am. 60, 230–239 (1976)]. By proper choices of echo-carrier-frequencies and antenna-dimensions, a quasiuniform phase distribution, in excellent agreement with modest phase shifts measured experimentally [Hall and Wescott, J. Acoust. Soc. Am. 56, 1376–1382 (1974)], is obtained by computer-simulations. Results of computer-predicted patterns and comparisons between theory and recent pattern measurements [Wescott, private communications (1976)] are presented. A measured 3-dB pattern beamwidth of 13° (average of two measurements) compares well with computer-prediction of 12.8°. Severe sidelobes are major detriments in Acoustic Remote Sensing. Other results presented include (1) ground-level sidelobes versus echo-carrier-frequencies, (2) 3-dB beam-width variations with echo-carrier frequencies and antenna dimensions, and (3) computer simulations of the antenna type employed in probing marine-atmosphere remotely from a moving ship. [Mandies and Owens, J. Appl. Meteorol. 14, 1110–1117 (1975)] during a cruise in the Pacific Ocean/Caribbean Sea. [Work supported by NRC.]
Some zero-crossing statistics of a signal consisting of band-limited white Gaussian noise with a pure tone added to it
Authors: Rowlands R. O.
Published: October 2005

The number of zero crossings per second of a band-limited white Gaussian noise signal x(t) is slightly greater than twice the midband frequency of the signal. This may be explained by considering the complex signal z(t) = x̂(t) + j x(t) where x̂(t) is the Hilbert transform of x(t). The vector z(t) rotates at a mean angular frequency that is equal to its mid-band angular frequency, but it has a jitter superimposed upon it that; on occasion, causes it to rotate in the opposite direction. The extra crossings are produced by the vector rotating backwards just after it has crossed the real axis in the forward direction. It is the statistics of these backward crossings that have been studied when a pure signal has been added to the noise. [Work supported by ONR Code 436.]
Source level measurements of 1.8 lb and 1.1 oz underwater sound signals
Authors: Thorleifson J. M. , Boyle P. D.
Published: October 2005

The source levels of underwater sound signals (SUS), containing 1.8 lb and 1.1 oz of TNT detonated at 60 and 600 ft, were measured experimentally at Jervis Inlet in November 1974. The measurements were made by recording the source pressure-time waveforms received on hydrophones placed about 1000 ft below the detonation depth. The measured source levels are compared with levels computed using a model based on Weston's analytical model [D. E. Weston, Proc. Phys. Soc. 76, 233–249 (1960)] and with Gaspin and Shuler's results [J. B. Gaspin and V. K. Shuler, Naval Ordnance Lab TR 71-160, Oct. 1971] for 1.8 lb of TNT detonated at 60 ft. For the 1.8-lb sources, the measured results are up to 5 dB different from the levels computed using the Weston model over the band 10–1600 Hz. However, the measured levels are in good agreement with those of Gaspin and Shuler. For the 1.1-oz source the measured results are up to 20 dB lower than the levels computed using the Weston model. This large reduction in level is likely due to energy lost in breaking through the SUS container.
Weak-shock solution for explosive shock waves
Authors: Rogers Peter H.
Published: October 2005

The initial pressure wave measured at modest distances from an underwater explosion is often modeled as a spherical shock wave with an exponential decay. A closed-form analytical “weak-shock” solution for the subsequent propagation of such a wave has been obtained. Simple formulas expressing the peak pressure and initial decay constant as function of reduced range are presented. These allow the prediction of the amplitude and initial slope of the wave given only the amplitude and decay constant of the original exponential shock and the density, sound speed and parameter of nonlinearity of the water. The results are in good agreement with the Kirkwood-Bethe theory, measurements, and the widely used experimentally based semiempirical similarity formulas. An expression which gives a close approximation to the waveform as a function of distance is also derived.
Vibrations of prolate spheroidal shells of constant thickness
Authors: Burroughs Courtney B. , Magrab Edward B.
Published: October 2005

The general displacement-equilibrium equations, which include the effects of transverse shear and rotary inertia, have been derived for a prolate spheroidal shell of constant thickness. The solution is formulated for a shell that is immersed in an inviscid fluid of infinite extent and subjected to an harmonically time-varying, arbitrarily spatially distributed force normal to the shell surface. The approximate formal solutions for the three displacements of the shell surface and the two rotations of the shell cross section are obtained using an extension of Galerkin's variational method developed by Chi and Magrab [Proceedings of the International Conference on Variational Methods in Engineering (University of Southampton, 1974)]. Numerical results are presented for the lowest seven axisymmetric natural frequencies of the shell in vacuo. Using 15-term solutions for both thick and thin shells, which have eccentricities that vary from 0.46 to 0.99, the approximate natural frequencies are found to converge to within less than 1% their final value. Good agreement with other published results for the approximate natural frequencies of a thin prolate spheroidal shell and for the exact natural frequencies of a thick spherical shell is obtained. Additional results for the natural frequencies of moderately thick shells as a function of shell eccentricity, mode number, and shell thickness are presented.
English intonation and computerized sound synthesis
Authors: Levine Arvin
Published: October 2005

Sentential intonation has been approached through the paradigms of acoustical engineering and linguistics. This research stresses the latter, treating pitch in English intonation as similar to tone languages [W. Leben, Linguistic Analysis 2.1 (1976)], and to song [M. Liberman, MIT dissertation (1975)]. Declarative intonation results from underlying melodies, consisting of a few discrete tones, interacting with a sentence's syntax and semantics. The melody for declaratives is M-H-L (a midtone followed by high and low tones). The syntactic structure determines how this melody is elaborated to fit the sentence. Typical questions have a different underlying melody, M-L-H, but the syntactic control of elaboration is the same. The semantics alters the elaboration and not the choice of an underlying melody so that changing the focus of a sentence alters the elaboration of the underlying melody and thus the perceived stress. We make concrete proposals for automatic generation of intonation contours: adding to written text the necessary pitch, duration and loudness parameters for computerized sound synthesis. Our intonation procedure has been incorporated in a computer-aided instruction program.
Study of variations in the male and female glottal wave
Authors: Mortsen H. B. , Engebretson A. M. , Vemula N. H.
Published: October 2005

Observations of glottal sound waves generated by five male and five female adults were made with a reflectionless tube. Speakers phonated a neutral vowel in normal, loud, and soft voice and in linguistically relevant syllables: monosyllables with interrogative and declarative intonation and three-syllable words with primary stress on one syllable. Two types of variation of the glottal waveform are observed, depending upon the sex of the speaker, the mode of phonation, and the linguistic context in which phonation is produced. In one case, the harmonic relations of the glottal spectrum remain the same over changing F0. In a different type of change, the harmonic relations decline more steeply with increasing F0 and the distribution of energy tends to remain constant. These results are compared with glottal waves generated by the Flanagan—Ishizaka two-mass model of the vocal folds in which subglottal air pressure and fold tension may be systematically varied. Comparison indicates that in declarative syllables, F0 change may be due primarily to declining air pressure, whereas in interrogative syllables, it appears due mainly to increased fold tension. [Supported by NINCDS Grant 03856.]
Overview of land use planning
Authors: Pepin-Donat M.
Published: October 2005

A new increasing awareness of the finite quality of land as a resource exists in the United States today. This change in perspective is challenging traditional practices resulting in conflicting values in American society. The issue of land use planning is extremely complex and influences by a multitude of independent yet interrelated factors such as government—local, State, and Federal, the citizen; the developer; the courts; industry and technology; and banking. Tradiationally, the right to plan and control land in the United States rests with each individual State. There are a minimum of 160 Federal programs—grant, loan, and regulatory, which impact land use in addition to individual State and local programs. A variety of tools and mechanisms have been developed to resolve the complex land use problem. Coordination is sought in all 50 States through an A-95 Clearinghouse mechanism and supplemental State programs. The courts are taking an increasingly active role in influencing the direction of land use planning. An attempt to relate recently enacted or proposed noise control legislation to these land use processes will be included.
Influence of noise control on land use planning
Authors: Bragdon C. R.
Published: October 2005

City planning has been an established professional discripline for nearly 50 years in the United States. Evolved from architecture mad other physically related disciplines city planning has broadened to also include interest in social and environmental concerns. Zoning was the first land use planning technique to incorporate noise performance requirements. Today many other land use planning techniques consider noise, among other environmental factors. An inventory of these planning techniques and their relative success are discussed, drawing upon municipal, state and Federal experiences. Recommendations are made for future courses of action to encourage greater effectiveness.
Overview of California's efforts in the area of planning for noise compatible land use
Authors: Illingworth R .R. , DuPree R. B.
Published: October 2005

This paper reviews the role of the California State Government in noise compatible lend use planning. Since the responsibility for land use planning in California lies almost entirely with local government, the State has provided, through various pieces of legislation, the means for insuring that noise is considered in the process. Among the approaches the State has adopted are (1) a requirement that cities and counties adopt a noise element as part of their general plan; (2) the establishment of an Office of Noise Control to provide assistance to local governments and coordinate efforts at the State level; (3) the establishment of airport land use commissions; (4) the use of the EIR/EIS review process; and (5) the adoption of noise insulation standards for multifamily dwellings. The effectiveness of these measures in achieving noise compatible land use is discussed. Examples of good and bad land use in the vicinity of various sources are presented and analyzed. Some alternative approaches are presented and pitfalls pointed out.
Estimation of the length of the traveling wave envelope from response areas of neurons in the cochlear complex of the cat
Authors: Hind J. E. , Rose J. E. , Gibson M. M. , Kitzes L. M.
Published: October 2005

Plots of discharge rate vs frequency at a number of intensities were determined for 163 neurons. Presumably the bandwidth of these response areas is determined by the shape of the traveling wave envelope on the basilar membrane. According to Greenwood, the distance from the peak to the apical foot of the wave is approximately constant [D. D. Greenwood, J. Acoust. Soc. Am. 34, 1364–1369 (1962)]. Using his frequency-distance function for the cat, we have calculated for each response area the distance along the basilar membrane between the locations for the best frequency and the upper cutoff frequency. When this “critical distance” (c.d.) is plotted versus best frequency for all units, c.d. tends to increase as best frequency declines below about 2 kHz. In order to obtain relatively constant c.d. throughout the entire frequency range, it is necessary to revise Greenwood's function such that the distances for the lower octaves deviate even more from a logarithmic representation than suggested by his original curve. [Supported by NIH grants NS 06225 ,and NS 12732.]
Effects of stimulus frequency on two-tone suppression
Authors: Abbas P. J.
Published: October 2005

Effects of stimulus frequency on two-tone suppression were investigated in single auditory-nerve fibers of anesthetized cats and compared with human psychophysical data. Discharge rate of single fibers was plotted as a function of stimulus level of a tone (f1) both alone and in the presence of a second tone f2. f2 was always well below the fiber's characteristic frequency and was held at a fixed sound pressure level appropriate to produce two-tone suppression. Rate functions for the two-tone stimulus were thus depressed or shifted horizontally with respect to the single-tone (f1) rate function. When f1 was varied with f2 fixed, suppression was maximum with f1 at fiber CF. A psychophysical experiment was also conducted with stimulus parameters similar to those above. In this case, however, the two-tone stimulus was used in a forward-masking paradigm similar to that used by Shannon [J. Acoust. Soc. Am. 59, 1460 (1976)]. The unmasking effect as a function of frequency and level was compared to the single-fiber data. [Research supported by NIH Grant FR-07035.]
Latency changes for unit responses at rat inferior colliculus after early auditory deprivation
Authors: Clopton B. M. , Silverman M. S.
Published: October 2005

A decrease in the latency of neural responses is a commonly reported concomittant of development in the auditory system. We investigated the effect of sound deprivation on the developing auditory system of rats by observing latency changes in unit responses at the inferior colliculus following deprivation. Ligation of one external meatus at ten days after birth produced partial sound deprivation until the ligation was removed two to five months later. Units at both colliculi were studied by acute recording to determine characteristic frequency (CF) and initial spike latencies for clicks of different intensities. At 30 dB above click threshold most units with high CF's that were activated by the deprived ear had response latencies two to three times the latencies for units of comparable CF's driven by the undeprived ear. Units with CF's below 10 kHz had essentially normal latencies. Observations at other sites indicate that neural, not mechanical changes are responsible for these findings. [Work supported by NIH Grant NS-13052.]
Variation of community noise sensitivity with time of day
Authors: Ollerhead J. B.
Published: October 2005

It is widely accepted that people are more annoyed by noise during the evening and nighttime hours than during the day period. Accordingly, many community-noise rating indices involve a division of the 24-h day into two or three time periods, attaching different weights to events in each. Unfortunately, it has proved very difficult to obtain quantitative measurements of these weightings through social survey studies, and consequently the weightings adopted tend to be based mostly upon intuitive judgments. This paper describes an attempt to obtain direct measurement of relative sensitivity to noise during the three periods. The measurements, which were made as a part of a wider study of the aircraft noise problem, support current estimates of increased sensitivity during the evening, but indicate a surprising immunity to noise during the night.
TTS from irregular bursts of noise
Authors: Ward W. D. , Cushing E. M. , Burns E. M.
Published: October 2005

Most studies of the TTS produced by noise have used regular interruptions of the noise; in general, such studies have shown that the TTS is proportional to the on fraction. However, such regularity is not characteristic of most industrial settings. In order to assess the effect of variability in burst and pause durations, the TTS produced in 10 young normal-hearing adults by 6-h exposures to magenta noise at 100 dBA, using an average on fraction of 50% but with four different temporal patterns, was measured. Exposure patterns were: (1) on 3 min, off 3 min during entire run; (2) on either 1 or 5 min (50% probability), off either 1 or 5 min, burst and pause durations independently selected; (3) on and off 1 or 5 min, pause duration same as preceding burst duration; and (4) on and off 1 or 5 min, pause duration different from preceding burst duration. No difference in TTS measured 2 or 30 min after exposure was found (maximum average TTS2 was 8 dB at 4 kHz), indicating that an intermittent noise can be adequately characterized by its average on fraction for purposes of exposure standards. [Research supported by the National Institute for Occupational Safety and Health, Public Health Service.]
Development of airport noise contours by extensive noise monitoring and analytical modeling
Authors: Horonjeff R. D.
Published: October 2005

This paper describes one of the first known efforts to combine analytical modeling techniques and extensive field noise monitoring to produce airport noise contours. The objective was to produce community noise equivalent level (CNEL) contours whose accuracy could be enhanced and defended by field measurements. An advanced computer simulation model (developed for the U. S. Air Force) was used in concert with 24-h noise monitor data at 44 locations surrounding Miramar Naval Air Station at San Diego, CA. A three-phase study was undertaken to satisfy the objective: (1) develop a preliminary set of contours using the analytical model and the best available data base, (2) use contours to select noise monitor locations and acquire monitor data, and (3) normalize monitor data to typical flying conditions and update noise contours. The paper discusses the variables involved in generating the contours, their ability to be reliably measured at reasonable cost, and their relative impact on contour accuracy.
Waterfront land use planning
Authors: Parry J. K. , Parry H. J.
Published: October 2005

Results of a comprehensive study of industrial land use to achieve maximum potential noise comparability with nearby residental communities are presented. Land use plans developed during the study were concerned with a variety of proposed projects at one large waterfront facility operated by the Port of Seattle and covering the time period of 1976–1980. During the study both adverse and beneficial noise impacts were identified using the criteria of the existing conditions at the facility and the Washington State Noise Standards. Emphasis in the paper presented is placed on the cost effectiveness of careful land use planning through a tradeoff comparison between different noise-abatement approaches. The results and discussions presented are based on measurements of noises made specifically for this study, during previous waterfront noise studies and those reported in the literature. Proposed and potential uses for the waterfront facility are described in the terminal layout plan along with projected construction and facility changes. These include relocation of roads, rail tracks, rail headings, location of ship unloading berths, truck and rail car loading ramps, and building demolitions and replacements.
Low-cost community-noise monitoring system
Authors: Chalupnik J. D.
Published: October 2005

A system for acquiring the statistical data base required to determine 24-h ambient-noise descriptors such as the day-night equivalent A-weighted sound pressure level (LDN) is described. The system is inexpensive and utilizes standard laboratory instruments extensively. It is designed to take hourly samples of 5–15-min duration on an analog tape recorder. The data is analyzed in the laboratory on a general purpose digital computer. Results of tests in which the system was compared with an all digital system are given. The system performs as expected and is very easy to use.
Neural firing patterns in the chinchilla cochlear nucleus after noise-induced asymptotic threshold shift
Authors: Salvi R. , Henderson D. , Hamernik R.
Published: October 2005

Chinchillas were exposed to an octave band of noise (CF = 4.0 kHz, 86 dB SPL) for three to five days. At the cessation of the noise, unit activity was sampled in the dorsal cochlear nucleus and ventral cochlear nucleus over a period of 1–12 h post-exposure. In previous experiments [J. Mills, J. Speech Hear. Res. 16, 426–438 (1973)], the same exposure produced 40 dB of asymptotic threshold shift at 2–8 kHz measured behaviorally. Single units having CF's below 1.0 kHz had normal tuning curves while those above 1.0 kHz had thresholds that were elevated, on the average, by 40 dB and, in some instances, by as much as 70 dB. Tuning curves from the high-threshold units were abnormally broad due to the shallow slope on the low-frequency side of the tuning curves. In some units only inhibitory areas were present, while in others, the threshold for the low-frequency inhibitory areas was considerably lower than for the excitatory area. Spontaneous activity from the high-threshold units appeared to be normal or lower than normal. The single unit results will be related to the postexposure behavioral audiogram and cochleagram.
Long-term, asymptotic threshold shift in chinchillas exposed to repetitive, reverberant, impulse noise
Authors: Blakeslee E. A. , Hynson K. , Hamernik R. P. , Henderson D.
Published: October 2005

Five monaural chinchillas were exposed to a repetitive, reverberant, impulse noise for ten days. The impulse-noise source was a mechanized hammer pounding on a steel plate at a rate of 1 impulse/sec. The average, peak over-pressure within the holding cage was 113 dB SPL. Auditory thresholds were determined before and after exposure at 0.5, 1, 1.4, 2. 2.8, 4, 8, and 16 kHz by means of a behavioral technique utilizing shock-avoidance conditioning. During exposure, thresholds at 0.5 and 8 kHz were monitored on a daily basis. Within eight hours from the start of the exposure, threshold shifts at both frequencies had reached asymptotic levels of from 30 to 40 dB. Upon removal from the noise, the threshold shift at 8 kHz recovered more rapidly than at 0.5 kHz; however, at 40 days, both had returned to within 10 dB of the pre-exposure thresholds. A maximum PTS of 20–30 dB was found at either 2 or 2.8 kHz. Cochleagrams were obtained for each animal 60 days following the exposure. The histological examination provided support for the audiological findings.
TTS in Squirrel monkeys. I. Low-frequency long duration noise
Authors: Burnham J. , Nielsen D. W. , Talley C. , Deer B.
Published: October 2005

Little data has been gathered concerning TTS in primates following long-term exposures to noise. In this study, squirrel monkeys were exposed to an octave band noise centered at 500 Hz for various durations up to 48 hours. Maximum TTS occurred at 750 and 500 Hz. An overall exposure SPL of 95 dB resulted in mean threshold shifts ranging from 7 dB for a 1-h exposure to 20 dB for a 48-h exposure. Recovery of TTS from all exposures at 95 dB SPL were complete within 48 hours for every subject. Comparison with the data of Melnick and Maves [Ann. Otol. 83, 820–828 (1974)] gathered on 10 human subjects indicates that both the development and recovery of TTS in squirrel monkeys is very similar to that found in humans for long-term exposures. Presently, the development and recovery of TTS to an octave-band noise centered at 4000 Hz is also being investigated. [This research supported by a Ford Foundation and an NIH grant to Henry Ford Hospital.]
Differential sensitivity to frequency and intensity in songbirds
Authors: Sinnott J. M. , Sachs M. B. , Hienz R. D.
Published: October 2005

Frequency- and intensity-difference limens were measured in two passerine species, the red-wing blackbird (Agelaius Phoeniceus) and the brown-headed cowbird (Molothrus Ater). Operant conditioning techniques which we described previously were employed. The techniques made use of key pecks as observing and report responses. Birds were reenforced with food for reporting changes in frequency or intensity in an ongoing train of tone bursts. Smallest Weber fractions were obtained at 4 kHz where the mean JND was 30 Hz or Δf/f=0.0075. The mean value of Δf/f was 0.015 at 1 kHz and 0.02 at 8 kHz. Birds were more sensitive to upward frequency shifts than to downward shifts at 1 and 2 kHz. Mean intensity JND's were 2.5 dB for a 1-kHz tone at 50 dB SL and 5.4 dB for a 20-dB-SL tone. [This work was supported by a grant from NINCDS.]
Auditory thresholds in the guinea pig determined by positive reinforcement methods
Authors: Prosen C. A. , Petersen M. R. , Moody D. B. , Stebbins W. C.
Published: October 2005

Auditory thresholds of six guinea pigs were determined employing operant conditioning techniques. Each subject was trained to nose-press a transluscent response disk (the observing response) mounted on the wall of the experimental chamber just above the floor. A tone was presented through a speaker on the chamber ceiling directly over the subject's head on a variable-interval schedule. The subject reported the tone by pressing once on a second response disk (the reporting response) mounted near the first. A small pellet of food was delivered following reporting responses made in the presence of a tone while a 15-sec time out followed false alarms. Thresholds from 125 to 45 000 Hz were determined by the method of constant stimuli. All subjects were most sensitive to test stimuli located between 4000 and 8000 Hz where the threshold ranged from −10 to 0 dBre 2×10−5 N/m2. A brief training period and the lack of significant variability between or within subjects indicate that the guinea pig is a reliable species for further behavioral auditory research, The behavioral audiogram attained agreed well with the determined in guinea pigs by recent investigators [Heffner, Heffner, and Masterton, J. Acoust. Soc. Am. 49, 1888–1895 (1971)] using an alternate behavioral procedure. [Supported by Research Grant NSO5077 and Program Project Grant NSO5785 from NINCDS.]
Apparatus and method for conditioning absolute frequency discrimination in the chinchilla
Authors: Hunter-Duvar I. M.
Published: October 2005

Absolute frequency discrimination typically has been an extremely difficult task for animals to learn. We have designed an avoidance conditioning apparatus for the chinchilla that offers the animal cues of location, shape, and color to assist it in making the correct response. The apparatus is used with a procedure which forces the animal to listen to the tone for several seconds before a choice can be made. Preliminary results indicate that animals can make a 2-octave discrimination at the 90% level in less than 500 trials.