bluuebunny/crossref_metadata_2025 huggingface dataset:
Interpretive principles and the quantum mysteries
Authors: Dotson Allen C.
Published: September 2005

Much has been written in recent years about the strange features associated with the quantum-mechanical description of nature at the atomic level. Physics teachers should help their students to see that many of these mysterious features are direct results of interpretive principles added to the basic theory of quantum mechanics, and that therefore they may or may not reflect the best possible understanding we can achieve of how nature works at that level. This paper discusses three such principles and their connection to well-known quantum mysteries. The practical significance of distinguishing between quantum mechanics itself and these principles is that it remains possible that other explanatory ideas may be found which lead to less mysterious consequences.
Do cathedral glasses flow?
Authors: Zanotto Edgar Dutra
Published: September 2005

A general belief among members of the scientific community is that glass articles can be bent irreversibly and that they flow at ambient temperature. This myth is mostly based on widespread stories that stained-glass windows of medieval cathedrals are thicker in the lower parts. In this paper I estimate the time periods required for glass to flow and deform at ordinary temperatures, using calculated viscosity curves for several modern and ancient glass compositions. The conclusion is that window glasses may flow at ambient temperature only over incredibly long times, which exceed the limits of human history.
The resonant excitation of a wineglass using positive feedback with optical sensing
Authors: Skeldon Kenneth D. , Nadeau Valerie J. , Adams Christopher
Published: September 2005

We describe an apparatus that will sense the vibration of a wineglass through the jitter induced on a laser beam reflected from the glass wall. A positive feedback system provides a high level sound-wave-train that maintains the vibration of the glass, while a light-emitting diode lighting panel, also deriving its signal from the feedback system, allows the motion of the glass to be clearly observed in a user-controllable way. The positive feedback signal, along with observations from some additional experiments, can be used to highlight some of the nonlinear aspects of the resonance. Although the apparatus is primarily intended as a demonstration exhibit, we have found it useful also as a physics teaching aid.
An experiment on electron wave–particle duality including a Planck constant measurement
Authors: Matteucci G. , Beeli C.
Published: September 2005

An alternative approach with respect to the standard double-slit experiment is presented to introduce the wave-like behavior of electrons. This simple and pedagogical experiment requires a commercial transmission electron microscope and a ferromagnetic film transparent to electrons. It allows in addition the measurement of Planck’s constant.
Space–time intervals as light rectangles
Authors: Mermin N. David
Published: September 2005

Two inertial observers in relative motion must each see the other’s clock running at the same rate. The representation of this symmetry of the Doppler effect in a two-dimensional space–time diagram reveals an important geometrical fact: The squared interval between two events is proportional to the area of the rectangle of photon lines with the events at diagonally opposite vertices.
Extensions of the Bohr–Sommerfeld formula to double-well potentials
Authors: Chebotarev L. V.
Published: September 2005

Extensions of the Bohr–Sommerfeld quantization formula to smooth double wells are established which preserve the formula’s generality and simplicity as well as its accuracy and the ease of use. Moreover, the proposed quantization equations for double wells, while being free from the limitations of the Wentzel–Kramers–Brillouin approximation which is restricted to deep energy levels alone, are equally well suited for determining higher energy levels lying in the vicinity of the barrier’s top as well as above the latter, and they have the correct connection to the conventional Bohr–Sommerfeld formula as the particle’s energy becomes large enough. As a particular application, a simple quantization equation for the pure quartic oscillator is derived which yields correct energy eigenvalues for all eigenstates of the oscillator including the ground one, with relative errors being all less than 1%. Conditions for the validity of the extended quantization equations are discussed and their numerical verification is made.
Newtonian jerky dynamics: Some general properties
Authors: Linz Stefan J.
Published: September 2005

We clarify and generalize the recently introduced concept of a Newtonian jerky dynamics. We also discuss several analytically accessible properties of these systems, including their general functional form, periodic solutions and conserved quantities, symmetries, and nonchaotic behavior.
Resource Letter ICQM-1: The Interplay between Classical and Quantum Mechanics
Authors: Gutzwiller Martin C.
Published: September 2005

This Resource Letter provides a guide to the literature that is concerned with the connections between classical and quantum mechanics. After the three centuries of classical mechanics, this fundamental problem in physics became one of the important issues at the beginning of the twentieth century, in the transitional period from 1900 to 1925. It then lost some of its urgency during the modern period from the discovery of Schrödinger’s equation to the middle of the 1960s, when the validity of quantum mechanics was tested in all the areas of application. The most recent 30 years are called the Post-Modern Period because both the classical and quantal aspects of nature are seen in their full complexity, and the advantages of viewing one in the light of the other have brought a better understanding of many special fields. The literature is divided into these four periods, and the list of references in each of them is subdivided according to the main areas of interest. Most of the bibliographic descriptions are accompanied by a short comment that is supposed to complete the information in the title.
Physics for Educationally Disadvantaged Students
Authors: Franklin Allan D.
Published: September 2005

We are reporting here on the results of a 1-yr introductory physics course for educationally disadvantaged students. Information on course enrollment, staffing, and format is included. The only teaching innovations used were edited lecture notes and a class council. Evaluation of student performance, including a comparison with students in other introductory physics courses, and student evaluations are also given.
Teaching Science to Nonscience Majors—Some Attitudes, Ideas, and Approaches
Authors: Cothern C. R.
Published: September 2005

The reasons for a nonscience major to take a science course are examined and discussed. The problems and some possible approaches in developing a course for the nonscience major are reviewed. The plan of this course involves combining “straight” physics with discussions of problems in the science and society area based on journal, magazine, and newspaper articles and some books. The major goal of this course is to change the attitudes of the students from fear and hostility towards science to an understanding and appreciation of how science contributes to their world and how they can contribute to a better relationship between science and society. An approach to the laboratory for such a course is described. An evaluation survey of attitudes of students before and after the course indicated a distinct change in attitudes. That is, the students lose their fear and hostility towards science. They become more aware of science in their day-to-day lives and indicate that they feel science is an important and useful part of their lives.
Einstein's Derivation of Planck's Radiation Law
Authors: Lewis Henry R.
Published: September 2005

Einstein's derivation, almost lost through distorted referencing, still contains insights and problems worth reconsidering after more than 40 years.
Plane Pendulum in Quantum Mechanics
Authors: Pradhan T. , Khare A. V.
Published: September 2005

A detailed quantum mechanical treatment of the motion of a plane pendulum is given. Exact solution of the Schrödinger equation shows that the energy eigenfunctions and eigenvalues go over to those of a plane rotator for vanishing acceleration due to gravity g and to those of a harmonic oscillator in the limit of infinitely massive bob. In view of this, perturbation calculations have been done using rotator and oscillator basis, and conditions for convergence of the perturbation series in both cases have been discussed.
A Method for Obtaining Force Law Information by Applying the Heisenberg Uncertainty Principle
Authors: Harney R. C.
Published: September 2005

Assuming only that the electromagnetic force between two charged bodies is mediated by “virtual” photons, and that the “strength” of the electromagnetic interaction scales as qα1/2, Coulomb's law is derived directly from Heisenberg's uncertainty relation between time and energy. Extension of this treatment to the nuclear force, assuming mediation by virtual mesons, yields a relation for the maximum range of the nuclear force, r<ƛc(meson). That is, the nuclear force acts only over distances less than the Compton wavelength of the mediating particle. Examination of the gravitational force law yields the results that the graviton must be massless and move at speed c and that the gravitational interaction should scale as im′(Gm02/ħc)1/2. These examples demonstrate how the application of the uncertainty principle may be used to yield information on the force laws due to the basic interactions.
Experiment to Demonstrate the Creation of Positron-Electron Pairs by Gamma Rays
Authors: Avignone F. T.
Published: September 2005

An efficient method of observing the creation of e+−e− pairs by gamma rays is described, The experiment consists of placing a radioactive source of Th228 inside of various target cylinders and observing the gamma rays from the subsequent annihilation of the positrons with residual electrons in the target. A standard scintillation coincidence system is employed. The results of an experiment to verify the Z2 dependence of the pair production cross section are presented.
Thermal Expansion Corrections when ΔT Is Not Small
Authors: Bartels Richard A.
Published: September 2005

The exact solution to the problem of calculating dimension changes due to thermal expansion is considered. The relationship between this exact solution and the approximation used for small temperature changes is discussed. An explicit numerical calculation is made for KCl over the temperature range 300 to 0°K.
Integrated Circuits in the Introductory Electronics Laboratory
Authors: English Thomas C. , Lind David A.
Published: September 2005

The use of an integrated circuit operational amplifier in an introductory electronics laboratory course for undergraduate science majors is discussed. The advantages of this approach and the implications for scientific instrumentation are pointed out. A number of experiments using this kind of operational amplifier, which are suitable for the undergraduate laboratory, are described. Finally, it is shown how the widely used Malmstadt-Enke Electronics Laboratory may be modified in a simple way to include the use of this type of device.
Op-Amps as Building Blocks in an Undergraduate Project-Type Electronics Lab
Authors: Babcock L. E. , Vignos J. H.
Published: September 2005

A project-type undergraduate laboratory in electronics is described which utilizes integrated circuit operational amplifiers as building blocks for the construction of larger systems. A very brief account of operational amplifiers, both ideal and nonideal is included for reference. To guide the physics teacher who has not kept pace with the rapid advances in electronics, a detailed description of the projects is given.
Some Ideas for the “Poets' Physics” Laboratory
Authors: Kammer D. W. , Shaltis L. W.
Published: September 2005

A description is given of a laboratory program suitable for a course in physics for nonscience majors. The laboratories are designed around two approaches: the basic concepts of modern physics and the physics of urban and environmental problems. Sample topics include the physics of music, art, transportation, pollution, and atomic power.
The Science in Science Fiction: A Seminar Course
Authors: Calame Gerald P.
Published: September 2005

A seminar course based on the science used in selected science-fiction stories is described. The format of the course consists of reading stories and then discussing the physics (e.g., antimatter, relativity) which serves as the scientific background for the story. A partial list of books read, together with the background theme and appropriate references, is given. The student reaction to the course is enthusiastic.
Self-Excited ac High Voltage Generation Using Water Droplets
Authors: Zahn Markus
Published: September 2005

By letting water drops fall through rings into cans, high voltage can be spontaneously generated with no external electrical excitation. Previous work concerning this type of electric influence machine for dc and three-phase ac high voltage generation is extended to include multiphase, multifrequency operation by considering N streams and N cans. A distributed equivalent circuit representation is used to calculate the natural frequencies of the system, where it is found that many overstable modes are present. Experimental observations with up to five cans are presented. This device can serve as a model for phenomena concerned with atmospheric electricity.
Wave Number Space Analysis of Propagation in Nonuniform Media
Authors: Brownell John H.
Published: September 2005

It is illustrated that the propagation of disturbances in nonuniform media can often be treated in terms of a differential equation in wavenumber space. The technique is illustrated by means of the one-dimensional wave equation.
Information and Entropy for a Planar Box
Authors: Hall G. G. , Jones S. B.
Published: September 2005

The information contained in the specification of the position of a particle inside a box at two instants is related to the entropy of the particle. Several approximations inherent in the discrete model are investigated using a numerical example.
GaAs Laser Experiments for the Undergraduate Laboratory
Authors: Hebner Robert E. , Jones J. Daniel , Nygaard Kaare J.
Published: September 2005

A set of laboratory experiments designed to investigate the properties of gallium arsenide lasers is reported. GaAs laser experiments are well suited for undergraduate laboratory because they provide an opportunity to study the physics of electro-optical devices for a minimum capital investment. The specific experiments presented in this paper describe the determination of the current necessary for “losing” to occur, an investigation of the variation of the wavelength of the emitted light as a function of the laser temperature, and a study of the polarization of the emitted light. All of the experiments presented have been used in an advanced undergraduate laboratory.
Conventions for Magnetic Quantities in SI
Authors: Coleman J. E.
Published: September 2005

Magnetic equations written in International Standard (SI) units usually use either the Sommerfeld convention (m = IA, H = B/μ0−M) or the Kennelly convention [m′ = μ0IA, H = 1/μ0(B−M′)]. An alternative is the “SI electric” convention (m = IA, H = B−μ0M) proposed by Stopes-Roe. In this paper it is shown that the “SI electric” convention arises naturally from the comparison of pole and current loop models for magnetic materials, and hence overcomes the problems of illogical factors of μ0 inherent in the Sommerfeld and Kennelly formulations. This approach clarifies the roles of the field vectors B and H.
A Low Cost X-Band IMPATT Diode Marginal Oscillator for EPR
Authors: Hogg R. D.
Published: September 2005

A simple, inexpensive, and easy to use IMPATT marginal oscillator for microwave electron paramagnetic resonance (EPR) with a sensitivity of about 2×1012 spins/gauss is presented. Construction and operating techniques are discussed and a section on troubleshooting is included.
On Fluctuations of Temperature in Small Systems
Authors: McFee Richard
Published: September 2005

Temperature is usually defined to be [(dS/dE)]−1. With a small system connected to a heat reservoir, there is a slight fluctuation of E, hence of the entropy S(E), hence of T. In this article it is shown that this definition implies that the average value of T is slightly higher than T0; however, the average of (1/T) is found to be (1/T0). It is also shown that the instantaneous Boltzmann factor exp(−E/kT) does not apply exactly to small systems, however, on the average, the Boltzmann factor exp(−E/kT0) does apply exactly.
Continuum Wave Functions in the Calculation of Sums Involving Off-Diagonal Matrix Elements
Authors: Ruffa A. R.
Published: September 2005

The method of analytical calculation of off-diagonal matrix elements for the hydrogen atom which involve the continuum wave functions is discussed in some detail. The method is then applied to the calculation of the continuum contribution of some infinite sums which represent known observables. It is demonstrated that the exact integral over all energies of the continuum is easy to obtain by analytical methods, involving approximately as much labor as the calculation of one matrix element involving a discrete state. Moreover, the continuum contribution to the sum is sometimes quite large, accounting, in extreme cases, for all but a few percent of the total.
A Sector-Type Beta-Ray Spectrometer: A Laboratory Experiment
Authors: Mudhole T. S. , Umakantha N.
Published: September 2005

A simple inexpensive sector-type beta-ray spectrometer which can be constructed using any available electromagnet with flat circular pole pieces is described. Such a spectrometer can be used to demonstrate the continuous nature of the beta spectrum and the existence of internal conversion lines, and also to determine the end-point energy of a beta spectrum by drawing the Fermi-Kurie plot.
Laser Optics Experiments with Glass Plates and a Modified Jamin Interferometer
Authors: Woolsey G. A.
Published: September 2005

A 1-mW He-Ne laser is used in three quantitative experiments which deal with the basic principles, assembly, and application of a modified form of Jamin interferometer. The interferometer, which uses two glass plates with finite wedge angles of the order of 1 minute of an arc, is cheap to construct, and is less susceptible to vibration than more conventional interferometers. The experiments described deal in turn with the measurement of wedge angle of a glass plate, the dependence on angle of incidence of the beam separation produced by a glass plate, and the measurement of the refractive index of air using the modified form of Jamin interferometer.
A Classical Magnetic Resonance Self-Oscillating Magnetometer
Authors: Wright John J. , Van Der Beken David
Published: September 2005

An undergraduate experiment and project are described which, on a macroscopic scale, introduce the student to several concepts underlying resonance phenomena and feedback networks. The student then applies these to construct a self-oscillating magnetometer.
Science Fiction Courses: An Example and Some Alternatives
Authors: Schmidt Stanley A.
Published: September 2005

Science fiction (SF) courses, recently increasing in popularity, are discussed with particular emphasis on their potential value in teaching and increasing student interest in science and science-society interactions. Several general types of SF courses are discussed, and a sample course which has been given at Heidelberg is described in some detail. Suggestions are given for others considering offering SF courses, including examples of reading lists and sources of additional information and teaching aids.
Simple Non-Coriolis Treatments for Explaining Terrestrial East-West Deflections
Authors: Wild John F.
Published: September 2005

While it is a powerful computational technique, the Coriolis method provides little physical insight into the origin of terrestrial east-west deflections of trajectories. These effects are best explained by viewing the trajectory from a nonrotating coordinate system. A search of textbooks and literature reveals an almost complete absence of such comparison treatments. Two comparison treatments are presented which have the pedagogically desirable features of brevity and mathematical simplicity while giving due emphasis to the fundamental physical principle involved, i.e., conservation of angular momentum.
The Effect of Magnetic Mass on Alfvén Waves
Authors: Jones Allen D.
Published: September 2005

In view of the intense magnetic field of the pulsars, the derivation of the speed of Alfvén waves is re-examined to determine the effect of the relativistic mass of the magnetic field. A stretched-string model is applied which gives an incorrect result. A wave equation is derived from the equation of motion, including electromagnetic momentum. A modified stretched-string model is shown to give a correct result.
Charged Particle in a Low Magnetic Field with Finite Boundary Conditions
Authors: Zwicker R. D. , Butler Frank A.
Published: September 2005

Exact wave functions are given for a charged particle in a uniform magnetic field, confined in one direction between two infinite potential barriers. The manner in which these wave functions proceed in the zero-field limit to free particle plane waves is explored with the aid of the WKB (Wentzel-Kramers-Brillouin) formalism. The energy eigenspectrum in the low-field case is found as the zero-field eigenspectrum plus correction terms in powers of the magnetic field. The form of the correction terms and other characteristics of the quantum mechanical problem are explained by comparison with the analogous problem in classical mechanics.
The inverse-scattering problem and global convergence
Authors: Norton Stephen J.
Published: September 2005

In solving nonlinear inverse-scattering problems an iterative approach is usually required, particularly if the nonlinearity is strong. A typical approach is to use a descent algorithm to minimize a global error norm, such as the mean-square error, to arrive at a set of parameters that best predicts the data based on an assumed model of the unknown scattering object. In minimizing the error norm, the possibility of converging to a local minimum can lead to false solutions. A different strategy is proposed that is not based on gradient descent which, at least in principle, should avoid local minima and converge to the true solution (the global minimum). A simple inverse-scattering problem is used as an illustration.
Target phase: An extra dimension for fish and plankton target identification
Authors: Barr Richard , Coombs Roger F.
Published: September 2005

The acoustic signal backscattered from a fish in water, Lbs(f), at a frequency, f, differs from the incident signal in both magnitude, ∣Lbs(f)∣, and phase, arg[Lbs(f)], and it has been common practice for many years to use the backscatter magnitude from individual fish as an aid to species identification. However, very little use has been made of the phase of the backscattered signal relative to that of the incident acoustic pulse. If the gross phase changes due to propagation through water are compensated for, the residual phase signature is found to contain useful target-specific information. The phase signature can be characterized by estimating the rate at which the echo phase changes, relative to the transmitted pulse, during the echo from a fish. Clear groups are produced when single fish targets from in situ data are plotted in complex target space (target strength versus target rate of change of phase) and this is explored here by computing the acoustic backscatter, in complex target space, from a series of simple large and small model fish targets, both with and without gas-filled swimbladders, using a Monte Carlo technique. It is shown that all the features found in the in situ data can be explained in terms of the size and attitude of the fish. The modeling was carried out at the frequency of 38 kHz, which pertained to the in situ data, and the specific results only apply to this frequency. However, the complex target approach is generally applicable to fish target strength analysis independently of frequency.
Measures of extents of laterality for high-frequency “transposed” stimuli under conditions of binaural interference
Authors: Bernstein Leslie R. , Trahiotis Constantine
Published: September 2005

Our purpose in this study was to determine whether across-frequency binaural interference would occur if ITD-based extents of laterality were measured using high-frequency transposed stimuli as targets. The results of an earlier study [L. R. Bernstein and C. Trahiotis, J. Acoust. Soc. Am. 116, 3062–3069 (2004)], which focused on threshold-ITDs, rather than extents of laterality, suggested that high-frequency transposed stimuli might be “immune” to binaural interference effects resulting from the addition of a spectrally remote, low-frequency interferer. In contrast to the earlier findings, the data from this study indicate that high-frequency transposed targets are susceptible to binaural interference. Nevertheless, high-frequency transposed targets, even when presented along with an interferer, yielded greater extents of ITD-based laterality than did high-frequency Gaussian noise targets presented in isolation. That is, the “enhanced potency” of ITDs conveyed by transposed stimuli persisted, even in the presence of a low-frequency interferer. Predictions made using an extension of the model of Heller and Trahiotis [L. M. Heller and C. Trahiotis, J. Acoust. Soc. Am. 99, 3632–3637 (1996)] accounted well for across-frequency binaural interference obtained with conventional Gaussian noise targets but, in all but one case, overpredicted the amounts of interference found with the transposed targets.
Effects of later-occurring nonlinguistic sounds on speech categorization
Authors: Wade Travis , Holt Lori L.
Published: September 2005

Nonspeech stimuli influence phonetic categorization, but effects observed so far have been limited to precursors’ influence on perception of following speech. However, both preceding and following speech affect phonetic categorization. This asymmetry raises questions about whether general auditory processes play a role in context-dependent speech perception. This study tested whether the asymmetry stems from methodological issues or genuine mechanistic limitations. To determine whether and how backward effects of nonspeech context on speech may occur, one experiment examined perception of CVC words with [ga]-[da] series onsets followed by one of two possible embedded tones and one of two possible final consonants. When the tone was separated from the target onset by 100 ms, contrastive effects of tone frequency similar to those of previous studies were observed; however, when the tone was moved closer to the target segment assimilative effects were observed. In another experiment, contrastive effects of a following tone were observed in both CVC words and CV nonwords, although the size of the effects depended on syllable structure. Results are discussed with respect to contrastive mechanisms not speech-specific but operating at a relatively high level, taking into account spectrotemporal patterns occurring over extended periods before and after target events.
A comparison of two different sound intensity measurement principles
Authors: Jacobsen Finn , de Bree Hans-Elias
Published: September 2005

The dominating method of measuring sound intensity in air is based on the combination of two pressure microphones. However, a sound intensity probe that combines an acoustic particle velocity transducer with a pressure microphone has recently become available. This paper examines, discusses, and compares the two measurement principles with particular regard to the sources of error in sound power determination. It is shown that the phase calibration of intensity probes that combine different transducers is very critical below 500 Hz if the measurement surface is very close to the source under test. The problem is reduced if the measurement surface is moved further away from the source. The calibration can be carried out in an anechoic room.
Binaural release from informational masking in a speech identification task
Authors: Gallun Frederick J. , Mason Christine R. , Kidd Gerald
Published: September 2005

Binaural release from informational masking (IM) was examined in a speech identification task. Target and masker sentences were processed into mutually exclusive frequency bands, thus limiting energetic masking (EM), and presented over headphones. In a baseline condition, both were presented monotically to the same ear (TmMm). Despite minimal frequency overlap between target and masker, the presence of the masker resulted in reduced performance, or IM. Presenting the target monotically and the masker diotically (TmM0) resulted in a release from IM. Release was also obtained by imposing interaural differences in level (ILDs) and in time (ITDs) on the maskers (TmMILD,TmMITD). Any masker with a perceived lateral position that differed from that of a truly monaural stimulus resulted in a similar amount of release from IM relative to TmMm. For binaural targets and maskers (T0MILD,T0MITD), release was seen whenever ITDs or ILDs differed between target and masker. These results suggest that binaural cues can be very effective in reducing IM. Because mechanisms based on differences in perceived location make predictions that are similar to those of nonlocation-based binaural mechanisms, a variant of the equalization-cancellation model is also considered.
Experimental demonstration of adaptive reverberation nulling using time reversal
Authors: Song H. C. , Hodgkiss W. S. , Kuperman W. A. , Roux P. , Akal T. , Stevenson M.
Published: September 2005

The concept of environmentally adaptive reverberation nulling using a time reversal mirror (TRM) recently has been described [Song et al., J. Acoust. Soc. Am. 116, 762–768 (2004)]. In this paper, monostatic reverberation nulling is demonstrated experimentally at 850 and 3500Hz using data from a shallow water experiment conducted off the west coast of Italy in April 2003. The active transmission of a seafloor spatial null from a vertical source array is shown to result in the attenuation by 3–5dB of prominent reverberation features with their levels being reduced to that of the more diffuse reverberation background.
Effects of aspirin on distortion product otoacoustic emission suppression in human adults: A comparison with neonatal data
Authors: Abdala Carolina
Published: September 2005

One of the distortion product otoacoustic emission (DPOAE) paradigms used to study cochlear function is DPOAE (2f1−f2) ipsilateral suppression. Newborns do not have adultlike DPOAE suppression. At 6000 Hz, infants show excessively narrow DPOAE suppression tuning and shallow growth of suppression for low-frequency suppressor tones. The source of this immaturity is not known but the outer hair cell (OHC) is one possible locus. In the present study, DPOAE suppression was measured at f2=1500 and 6000 Hz from two groups with impaired OHC function in an attempt to model the observed immaturity in neonates: adults with aspirin-induced OHC dysfunction and subjects with sensorineural hearing loss (SNHL). Their DPOAE suppression results were compared to those obtained from a group of term newborns to address whether infant DPOAE suppression resembles suppression from individuals with known OHC dysfunction. Results indicate that aspirin systematically alters DPOAE suppression in adults at f2=6000Hz, but not 1500 Hz. However, neither aspirin-induced OHC dysfunction nor naturally occurring SNHL produces “neonatal-like” DPOAE suppression at either test frequency. This finding does not support the hypothesis that non-adultlike DPOAE suppression characterizing newborns can be explained by minor impairments or alterations of OHC function.
Properties of transducers and substrates for high frequency resonators and sensors
Authors: Wittstruck R. H. , Emanetoglu N. W. , Lu Y. , Laffey Sally , Ballato Arthur
Published: September 2005

Properties of transducers and substrates for bulk acoustic wave resonators and sensors are described. These resonators utilize one-dimensional thickness vibrations of structures consisting of a low-loss substrate crystal surmounted by a thin active piezoelectric film that drives the composite in resonant modes to achieve gigahertz frequencies. The structures considered include oblique orientations of the substrate, leading to generation of coupled elastic modes in the composite. A modified Christoffel-Bechmann (CB) formalism is presented to calculate acoustic wave speeds and displacements in the piezoelectric film transducer and the substrate. The CB method also yields the piezoelectric coupling coefficients of arbitrarily oriented piezofilms, for electric fields impressed either along the thickness or laterally. The calculations apply generally to transducer and substrate crystals of any symmetry class. The piezoelectric portion is then made specific for films of class 6mm (wurtzite structure) with arbitrary orientation on the substrate, and the substrate calculations are specified for class 3¯m materials, but apply also to any substrate with 3m or 32 symmetry. Zinc oxide and sapphire are used in an example of the acoustic resonator structure.
Underwater hearing sensitivity of a male and a female Steller sea lion (Eumetopias jubatus)
Authors: Kastelein Ronald A. , van Schie Robbert , Verboom Wim C. , de Haan Dick
Published: September 2005

The unmasked underwater hearing sensitivities of an 8-year-old male and a 7-year-old female Steller sea lion were measured in a pool, by using behavioral psychophysics. The animals were trained with positive reinforcement to respond when they detected an acoustic signal and not to respond when they did not. The signals were narrow-band, frequency-modulated stimuli with a duration of 600ms and center frequencies ranging from 0.5to32kHz for the male and from 4to32kHz for the female. Detection thresholds at each frequency were measured by varying signal amplitude according to the up–down staircase method. The resulting underwater audiogram (50% detection thresholds) for the male Steller sea lion showed the typical mammalian U-shape. His maximum sensitivity (77dB re: 1μPa,rms) occurred at 1kHz. The range of best hearing (10dB from the maximum sensitivity) was from 1to16kHz (4 octaves). Higher hearing thresholds (indicating poorer sensitivity) were observed below 1kHz and above 16kHz. The maximum sensitivity of the female (73dB re: 1μPa,rms) occurred at 25kHz. Higher hearing thresholds (indicating poorer sensitivity) were observed for signals below 16kHz and above 25kHz. At frequencies for which both subjects were tested, hearing thresholds of the male were significantly higher than those of the female. The hearing sensitivity differences between the male and female Steller sea lion in this study may be due to individual differences in sensitivity between the subjects or due to sexual dimorphism in hearing.
Types, distribution, and seasonal occurrence of sounds attributed to Bryde’s whales (Balaenoptera edeni) recorded in the eastern tropical Pacific, 1999–2001
Authors: Heimlich Sara L. , Mellinger David K. , Nieukirk Sharon L. , Fox Christopher G.
Published: September 2005

Vocalizations resembling known Bryde’s whale sounds were recorded on autonomous hydrophones at seven sites in the eastern tropical Pacific. Five short (<3s) low-frequency (<80Hz) “phrase” types were observed. “Swept alternating tonal” phrases included a 37-Hz tone and often a 25–16-Hz downswept tone, while “nonswept alternating tonal” phrases had a predominant tone at 29Hz and often additional tones at 16 and 47Hz. Alternating tonal phrases were found in 79% of the total hours in which phrases were detected, and occurred primarily at the eastern hydrophone sites. “Burst-tonal” phrases included tones that were often preceded by a wideband burst of noise. The “low burst-tonal” phrase contained tones at 19 and 30Hz, and was detected at five of the hydrophone sites. The “high burst-tonal” phrase included a 42-Hz tone and was observed only on the northwestern hydrophones. A single “harmonic tone” phrase type was observed that included a fundamental tone at 26Hz and at least two harmonics; this phrase was observed exclusively at the eastern hydrophone stations. This opportunistic survey has shown that acoustics is an effective means of studying this poorly understood, pelagic balaenopterid.
Informational masking release in children and adults
Authors: Hall Joseph W. , Buss Emily , Grose John H.
Published: September 2005

This study assessed informational masking and utilization of cues to reduce that masking in children aged 4–9years and in adults. The signal was a train of eight consecutive tone bursts, each at 1kHz and 60ms in duration. Maskers were comprised of a pair of synchronous tone-burst trains, with randomly chosen frequencies spanning 200–5000Hz, with a protected region 851–1175Hz. In the reference condition, maskers were eight bursts in duration, with a fixed frequency within intervals. Experiment 1 tested two monotic masking release conditions: within-interval randomization of masker burst frequency and the introduction of leading masker bursts. Experiment 2 examined masking release in which the signal was presented to one ear and masking components were presented to both ears (masker components in the contralateral ear were 10dB higher than those in the ipsilateral ear). Both adults and children demonstrated a significant informational masking effect, with children showing a larger effect on average. Both groups also showed significant release from masking in the two monotic conditions, although children received somewhat less benefit from the masking release cues. The binaural condition supported a moderate release from informational masking in adults, but resulted in increased informational masking in children.
Compact nonporous windscreen for infrasonic measurements
Authors: Shams Qamar A. , Zuckerwar Allan J. , Sealey Bradley S.
Published: September 2005

Infrasonic windscreens, designed for service at frequencies below 20Hz, were fabricated from a variety of materials having a low acoustic impedance, and tested against four specifications (the first three in a small wind tunnel): (1) wind-generated noise reduction (“insertion loss”) at a free-stream wind speed of 9.3m∕s, (2) transmission of low-frequency sound from a known source (subwoofer), (3) spectrum of sound generated from trailing vortices (aeolian tones), and (4) water absorption (to determine suitability for all-weather service). The operating principle is based on the high penetrating capability of infrasound through solid barriers. Windscreen materials included three woods (pine, cedar, and balsa), closed-cell polyurethane foam, and Space Shuttle tile material. The windscreen inside diameter ranged from 0.0254to0.1016m (1to4in.), and wall thickness from 0.003175to0.01905m (18to34in.). A windscreen made of closed-cell polyurethane foam revealed a wind noise reduction of 10–20dB from 0.7to25Hz, transmission coefficient near unity from 10to20Hz, and spectral peaks beyond 20Hz due to vortex-generated sound. Following a description of past methods, the principle of operation, and the experimental method, experimental data are presented for a variety of windscreens.
Probability distributions for locations of calling animals, receivers, sound speeds, winds, and data from travel time differences
Authors: Spiesberger John L.
Published: September 2005

A new nonlinear sequential Monte Carlo technique is used to estimate posterior probability distributions for the location of a calling animal, the locations of acoustic receivers, sound speeds, winds, and the differences in sonic travel time between pairs of receivers from measurements of those differences, while adopting realistic prior distributions of the variables. Other algorithms in the literature appear to be too inefficient to yield distributions for this large number of variables (up to 41) without recourse to a linear approximation. The new technique overcomes the computational inefficiency of other algorithms because it does not sequentially propagate the joint probability distribution of the variables between adjacent data. Instead, the lower and upper bounds of the distributions are propagated. The technique is applied to commonly encountered problems that were previously intractable such as estimating how accurately sound speed and poorly known initial locations of receivers can be estimated from the differences in sonic travel time from calling animals, while explicitly modeling distributions of all the variables in the problem. In both cases, the new technique yields one or two orders of magnitude improvements compared with initial uncertainties. The technique is suitable for accurately estimating receiver locations from animal calls.
Linear independence method for system identification/secondary path modeling for active control
Authors: Kim Benjamin J. , Swanson David C.
Published: September 2005

A method for noninvasive system identification/secondary path modeling has been developed for single- and multi-channel filtered-x least-mean-square (LMS)-based active noise control (ANC). The problem of on-line secondary path modeling is recognized as one of linear dependence associated with an underdetermined system, a one-equation/two-unknown problem in which the highly correlated primary source and secondary source contributions to the error signal are not readily distinguishable. The method resolves this uniqueness issue by introducing a second equation with similar unknowns. The critical linear independence of the two equations, hence the proposed designation, is achieved with a single perturbation of the control filter output, thereby rendering the system solvable. This secondary path modeling strategy was implemented using an innovative real-time DSP control architecture and tested on a “transducerless” system devised to investigate behavior of ANC algorithms. Results of narrowband, broadband, and multi-channel tests reveal response estimates that are accurate in both magnitude and phase; bias due to primary noise and other secondary sources is notably absent in the obtained secondary path models. The rapidity with which the system is identified can also contribute to the stability and performance of filtered-x LMS-based controllers.
An experimental investigation of two module configurations for use in active segmented partitions
Authors: Leishman Timothy W. , Tichy Jiri
Published: September 2005

Individual modules intended for active segmented partitions should be carefully analyzed before they are advanced as viable tools for active sound transmission control. In this paper we present experimental evaluations of two vibration-controlled modules: a single-composite-leaf (SCL) configuration and a double-composite-leaf (DCL) configuration. Experimental apparatuses and procedures are introduced to assess their normal-incidence transmission losses over a bandwidth from 40 to 1970 Hz. The average transmission loss of the passive SCL module is found to be 21 dB. If its transmitting diaphragm acceleration is minimized through active control, transmission loss increases somewhat at lower frequencies but decreases at higher frequencies, producing no increase in the average value. The average transmission loss of the passive DCL module is found to be 43 dB. After its transmitting diaphragm acceleration is actively minimized, the transmission loss increases substantially at all frequencies (especially at low frequencies), to produce an average value of 77 dB. Thus, while both configurations have the same underlying control objective, the DCL module yields a 56 dB average improvement over the SCL module through simple configurational changes. An alternative control scheme is investigated that minimizes acoustic pressure in the DCL module cavity, but it is found to be less effective.
The effects of high presentation levels on consonant feature transmission
Authors: Hornsby Benjamin W. Y. , Trine Timothy D. , Ohde Ralph N.
Published: September 2005

The effect of high speech presentation levels on consonant recognition and feature transmission was assessed in eight participants with normal hearing. Consonant recognition in noise (0 dB signal-to-noise ratio) was measured at five overall speech levels ranging from 65 to 100 dB SPL. Consistent with the work of others, overall percent correct performance decreased as the presentation level of speech increased [e.g., G. A. Studebaker, R. L. Sherbecoe, D. M. McDaniel, and C. A. Gwaltney, J. Acoust. Soc. Am. 105(4), 2431–2444 (1999)]. Confusion matrices were analyzed in terms of relative percent information transmitted at each speech presentation level, as a function of feature. Six feature sets (voicing, place, nasality, duration, frication, and sonorance) were analyzed. Results showed the feature duration (long consonant duration fricatives) to be most affected by increases in level, while the voicing feature was relatively unaffected by increases in level. In addition, alveolar consonants were substantially affected by level, while palatal consonants were not. While the underlying mechanisms responsible for decreases in performance with level increases are unclear, an analysis of common error patterns at high levels suggests that saturation of the neural response and/or a loss of neural synchrony may play a role.
Developing a speech intelligibility test based on measuring speech reception thresholds in noise for English and Finnish
Authors: Vainio Martti , Suni Antti , Järveläinen Hanna , Järvikivi Juhani , Mattila Ville-Veikko
Published: September 2005

A subjective test was developed suitable for evaluating the effect of mobile communications devices on sentence intelligibility in background noise. Originally a total of 25 lists, each list including 16 sentences, were developed in British English and Finnish to serve as the test stimuli representative of adult language today. The sentences, produced by two male and two female speakers, were normalized for naturalness, length, and intelligibility in each language. The sentence sets were balanced with regard to the expected lexical and phonetic distributions in the given language. The sentence lists are intended for adaptive measurement of speech reception thresholds (SRTs) in noise. In the verification of the test stimuli, SRTs were measured for ten subjects in Finnish and nine subjects in English. Mean SRTs were −2.47 dB in Finnish and −1.12 dB in English, with standard deviations of 1.61 and 2.36 dB, respectively. The mean thresholds did not vary significantly between the lists or the talkers after two lists were removed from the Finnish set and one from the English set. Thus the numbers of lists were reduced from 25 to 23 and 24, respectively. The statistical power of the test increased when thresholds were averaged over several sentence lists. With three lists per condition, the test is able to detect a 1.5-dB difference in SRTs with the probability of about 90%.