bluuebunny/crossref_metadata_2025 huggingface dataset:
Authentic and Simulated Professional Development: Teachers Reflect What is Modeled
Authors: Hanegan Nikki , Friden Kelley , Nelson C. Riley
Published: March 2010

Science is a dynamic discipline, representative of the nature of science. Yet, young science students continue to think everything is already discovered. In this study, we examine why students are not actively doing science. From professional development to student engagement, how are classrooms and students changing as we increase teachers' content knowledge? Teaching practices modeled in professional development can change what occurs in the classroom. Our study was designed to probe differences in two different types of professional development programs both focused on content knowledge. We found that what is modeled by the professional developers has a profound effect on the direction of the classroom. This matched controlled study found that teachers reflect the teaching practice modeled by professional developers through their individual classroom teaching practices. A significant difference was found in cognitive activities and questioning skills between teachers in a professional development program modeling authentic inquiry versus the teachers in a professional development modeling simulated inquiry. While both groups increased the amount of overall inquiry used in the classroom, students whose teachers were in authentic inquiry professional development were engaged in higher cognitive activities and questioning skills. If students are engaged in dynamic classrooms, searching for answers to students' questions, perhaps they will understand that science is a dynamic discipline.
Understanding the Affects of Audience on Mathemtaical Writing
Authors: Seo Byung‐In
Published: March 2010

This study formally explored how high school students addressed audience when they wrote mathematically. Student explicated the solving of a mathematics problem to their mathematics teacher and their English teacher. This study showed that students did change the style and language of their mathematical writing as their audience changed. It adds knowledge and support to current ideas of teacher presentation during routine daily instruction. Also included are implications this information may have on mathematics education.
Effect of Similarity‐Based Guided Discovery Learning on Conceptual Performance
Authors: Mandrin Pierre‐A , Preckel Daniel
Published: March 2010

Analogies are known to foster concept learning, whereas discovery learning is effective for transfer. By combining discovery learning and analogies or similarities of concepts, attractive new arrangements emerge, but do they maintain both concept and transfer effects? Unfortunately, there is a lack of data confirming such combined effectiveness. This experimental study involving 280 young students in the domain of physics showed that adequately structured similarities between mechanics and geometry improves conceptual performance (perception of functional relations) by as much for discovery learning as for conventional teaching texts with questions. Adequate structures were provided following Glynn's teaching with analogy model. The learning form had no significant impact on concept performance. The effect of similarity increased when the level of difficulty of the treatment was raised. These results were found using a 2 × 2‐factorial design. A qualitative questionnaire provided individual information about the usefulness of similarities and about learning strategies of the participants.
Understanding of Earth and Space Science Concepts: Strategies for Concept‐Building in Elementary Teacher Preparation
Authors: Bulunuz Nermin , Jarrett Olga S.
Published: March 2010

This research is concerned with preservice teacher understanding of six earth and space science concepts that are often taught in elementary school: the reason for seasons, phases of the moon, why the wind blows, the rock cycle, soil formation, and earthquakes. Specifically, this study examines the effect of readings, hands‐on learning stations, and concept mapping in improving conceptual understanding. Undergraduates in two sections of a science methods course (N= 52) completed an open‐ended survey, giving explanations about the above concepts three times: as a pretest and twice as posttests after various instructional interventions. The answers, scored with a three point rubric, indicated that the preservice teachers initially had many misconceptions (alternative conceptions). A two way ANOVA with repeated measures analysis (pretest/posttest) demonstrated that readings and learning stations are both successful in building preservice teacher's understanding and that benefits from the hands‐on learning stations approached statistical significance. Concept mapping had an additive effect in building understanding, as evident on the second posttest. The findings suggest useful strategies for university science instructors to use in clarifying science concepts while modeling activities teachers can use in their own classrooms.
Beginning Mathematics Teachers' Beliefs of Subject Matter and Instructional Actions Documented Over Time
Authors: Marbach‐Ad Gili , McGinnis J. Randy
Published: March 2010

In this study we report the results of survey research that collected responses of an identical sample (31 beginning mathematics and science teachers, elementary and middle school level) that graduated from a reform‐based mathematics and science teacher preparation program, the Maryland Collaborative for Teacher Preparation (MCTP). Our aim was to compare responses of the same beginning teachers over the two administrations of the survey. We administered the identical survey instrument in two separate batches spreading over nearly a four‐year period (1st batch fall 1999 through fall 2001; 2nd batch summer 2002). The first administration (pre‐test) was conducted soon after the beginning teachers graduated from the teacher preparation program and had not started full teaching. The second administration (post‐test) was conducted after the new teachers had taught full time for a minimum of a full year, with the majority having taught for two years. The instrument was crafted to measure the constructs of interest, MCTP Teacher's Beliefs and Actions of Mathematics and Science. Results for teachers who taught for at least two years indicated that in all areas the MCTP teachers maintained their reform‐based beliefs and actions after their induction years. These findings provide evidence for the sustainability of positive impact in the workplace resulting from a reform‐based undergraduate teacher preparation program.
Preservice Teachers' Analysis of Children's Work to Make Instructional Decisions
Authors: Cooper Sandi
Published: March 2010

Teaching is an interactive process in which teachers gather information, analyze the results, and construct a response based on this diagnosis (Cooney, 1988). Considering alternatives in constructing a response, that is, making an instructional decision, is of great importance in teaching. How might mathematics teacher educators provide experiences for preservice teachers to begin the development of this skill? In an attempt to determine how these experiences might reveal the level of understanding preservice teachers have in regards to children's mathematical thinking, a study was conducted over three semesters. During the mathematics methods course, preservice teachers were involved in analyzing children's work through the review and discussion of several samples. They were required to determine the error pattern, discuss what might have lead to this misconception, and suggest appropriate instructional strategies that might help this student. Although most preservice teachers could correctly identify the computational error patterns, they had difficulty in determining what might have led to the misconceptions and proposing effective instructional strategies.
Optical and electrical quality improvements of undoped InAs∕GaSb superlattices
Authors: Haugan H. J. , Ullrich B. , Grazulis L. , Elhamri S. , Brown G. J. , Mitchel W. C.
Published: March 2010

The performance and operating temperature of infrared (IR) detectors are largely limited by thermal generation and noise processes in the active region of the device. Particularly, excess background charge carriers enhance dark currents and depress the detector figures of merit. Therefore, reducing the overall defects and background carriers in the undoped region of p-i-n diodes is an important issue for developing high-operating temperature IR detectors. In this article, the authors discuss how several postgrowth annealing conditions and interface shutter sequences are optimized to reduce the density of nonradiative defect trap centers and background carriers and studied their relevance to the photoluminescence (PL) emission qualities of typical mid-IR InAs∕GaSb superlattices (SLs). Among the several in situ postgrowth annealing temperatures investigated, the SLs annealed at 450°C had the highest carrier density and the lowest PL intensity, while the SLs annealed at 475°C had the lowest carrier density and the highest PL intensity. In situ annealing did not change the carrier type, but slightly reduced the carrier densities as compared to the as-grown SL sample of 1.8×1011cm−2. While in situ annealing improves the surface morphological quality and the PL intensity, ex situ annealing creates many surface pits and significantly reduces the PL intensity. The carrier density was sensitive to the variation in interface composition control. With a minor variation in the interface shutter sequence, the carrier density dramatically increased from ∼2×1011to5×1012cm−2, and the corresponding mobility decreased from 6600to26cm−2∕Vs, indicating a degradation of the interfacial quality. All of the SL samples investigated for this study were p-type.
Two step optimized process for scanning tunneling microscopy tip fabrication
Authors: Bastiman F. , Cullis A. G. , Hopkinson M. , Briston K. J.
Published: March 2010

Fabrication of ultrasharp tips for scanning tunneling microscopy is inherently a two-step procedure, typically involving an etch process and postetch cleaning. From the myriad of etching parameters available in literature a procedure is presented that allows quantitative optimization and the routine production of tips with 3–10 nm radius of curvature. These ideally shaped tips require final oxide removal. Utilizing a custom designed e-beam heater element, oxide removal without localized melting is realized.
Causal analysis of the viscoelastic Lamb problem
Authors: Moura André
Published: March 2010

A mathematical development is given for the generation of viscoelastic waves by an impulsive line source acting on the interface of a viscoelastic half space, where the viscoelasticity is characterized by two relaxation processes. The considered idealized viscoelastic medium is isotropic and characterized by two Lamé constants appropriate for low frequencies, by their increments associated with the shift from low to high frequencies, and by separate relation times associated with each of the Lamé constants. A causal solution is developed using integral transforms and an extension of Cagniard's method
Sound emission and reception tuning in three cicada species sharing the same habitat
Authors: Sueur Jérôme , Windmill James F. C. , Robert Daniel
Published: March 2010

Many animal species acoustically communicate at the same place and time generating complex acoustic environments. However, the acoustic parameter space is usually structured, with each species emitting identifiable signals. While signal partitioning has been reported, very few analyses include the mechanical spectral response of auditory organs. The loud chorus generated by three cicadas (Cicada orni, Cicadatra atra, and Lyristes plebejus) was studied. The vibration pattern of L. plebejus shows traveling waves as previously observed in Ctra. atra. The spectral properties of both calling songs and tympanal auditory systems primarily indicate that each species uses its own frequency band. Male tympanal membranes (TMs) are tuned to their own song’s dominant frequency, except for C. orni, which is sensitive to the lowest frequency band of its song. In contrast, female TMs are broadly tuned to the male songs. Ctra. atra females differ by tuning to frequencies slightly higher than the male song. Hence, acoustic space partitioning occurs for both emitter and receiver, but does not seem to fully preclude interference risk as some spectral overlap exists. In addition to the local physical ecology of each species, selective attention to conspecific signals is likely to be enhanced by further mechanical and neuronal processing.
Local cochlear damage reduces local nonlinearity and decreases generator-type cochlear emissions while increasing reflector-type emissions
Authors: Dong Wei , Olson Elizabeth S.
Published: March 2010

Distortion product otoacoustic emissions (DPOAEs) originate in cochlear nonlinearity and emerge into the ear canal as an apparent sum of emission types, one of which (generator) travels directly out and the other (reflector) travels out following linear reflection. The present study explores intracochlear sources of DPOAEs via simultaneous ear canal and intracochlear pressure measurements in gerbils. A locally damaged cochlea was produced with reduced local intracochlear nonlinearity and significant elevation of the compound action potential thresholds at frequencies represented within the damaged region. In the DPOAE the comparison of healthy to locally damaged cochleae showed the following: (1) In the broad frequency region corresponding to the locally damaged best frequency, DPOAEs evoked by wider f2/f1 stimuli decreased, consistent with the reduction in local nonlinearity. (2) DPOAEs evoked by narrow f2/f1 stimuli often had a bimodal change, decreasing in a lower frequency band and increasing in a band just adjacent and higher, and the DPOAE phase-vs-frequency slope steepened. These changes confirm the complex nature of the DPOAE.
A relationship between the far field diffraction pattern and the axial pressure radiating from a two-dimensional aperture
Authors: Pees Edward H.
Published: March 2010

The diffraction of an acoustic wave by a two-dimensional aperture produces a sound field that can generally be represented at any point in space as a superposition of a continuum of plane waves. The mathematical formulation that facilitates this representation is known as the angular spectrum of plane waves method. The spectrum, in this representation, is a wavenumber spectrum obtained from a two-dimensional Fourier transform of the acoustic pressure (or velocity) distribution over the surface of the aperture boundary; a quantity which is also known to characterize the Fraunhofer diffraction pattern of the aperture. In this article, the angular spectrum method is used to formulate a mathematical relationship for two-dimensional apertures between the Fraunhofer diffraction pattern and a one-dimensional Fourier transform of the axial pressure. This relationship can be used to rapidly compute the axial pressure profile of the aperture if the boundary condition on the aperture is known and, in some cases, can be used as an inverse method. The approach is demonstrated for the cases of a flat circular piston and a flat rectangular piston undergoing harmonic motion in an infinite, rigid baffle. In the latter case, an analytical solution is also obtained.
Asymptotic evaluation of the pulse train radiated by an angled beam and fluid coupled rectangular ultrasonic transducer
Authors: Zakharov D. D. , Fradkin L. Ju.
Published: March 2010

The near field underneath the ultrasonic probe fluid coupled to an isotropic solid is approximated in the frequency domain by a closed form asymptotic solution. The approximation is based on the problem decomposition and uses the stationary phase method evaluating the response to an equivalent surface source. This results in a sum of contributions, each dominating in a specific geometrical region, the main beam or a side lobe. The transitional zones are also described. The pulse trains are computed using the harmonic synthesis and compared with the results obtained by direct calculation of Fourier integrals. It is shown that the asymptotic approach permits us to elucidate the physics of problem and leads to a numerical algorithm which is about 104 times faster than the direct computations.
How stable are acoustic metrics of contrastive speech rhythm?
Authors: Wiget Lukas , White Laurence , Schuppler Barbara , Grenon Izabelle , Rauch Olesya , Mattys Sven L.
Published: March 2010

Acoustic metrics of contrastive speech rhythm, based on vocalic and intervocalic interval durations, are intended to capture stable typological differences between languages. They should consequently be robust to variation between speakers, sentence materials, and measurers. This paper assesses the impact of these sources of variation on the metrics %V (proportion of utterance comprised of vocalic intervals), VarcoV (rate-normalized standard deviation of vocalic interval duration), and nPVI-V (a measure of the durational variability between successive pairs of vocalic intervals). Five measurers analyzed the same corpus of speech: five sentences read by six speakers of Standard Southern British English. Differences between sentences were responsible for the greatest variation in rhythm scores. Inter-speaker differences were also a source of significant variability. However, there was relatively little variation due to segmentation differences between measurers following an agreed protocol. An automated phone alignment process was also used: Rhythm scores thus derived showed good agreement with the human measurers. A number of recommendations for researchers wishing to exploit contrastive rhythm metrics are offered in conclusion.
Pharyngeal articulation in the production of voiced and voiceless fricatives
Authors: Proctor Michael I. , Shadle Christine H. , Iskarous Khalil
Published: March 2010

A structural magnetic resonance imaging study has revealed that pharyngeal articulation varies considerably with voicing during the production of English fricatives. In a study of four speakers of American English, pharyngeal volume was generally found to be greater during the production of sustained voiced fricatives, compared to voiceless equivalents. Though pharyngeal expansion is expected for voiced stops, it is more surprising for voiced fricatives. For three speakers, all four voiced oral fricatives were produced with a larger pharynx than that used during the production of the voiceless fricative at the same place of articulation. For one speaker, pharyngeal volume during the production of voiceless labial fricatives was found to be greater, and sibilant pharyngeal volume varied with vocalic context as well as voicing. Pharyngeal expansion was primarily achieved through forward displacement of the anterior and lateral walls of the upper pharynx, but some displacement of the rear pharyngeal wall was also observed. These results suggest that the production of voiced fricatives involves the complex interaction of articulatory constraints from three separate goals: the formation of the appropriate oral constriction, the control of airflow through the constriction so as to achieve frication, and the maintenance of glottal oscillation by attending to transglottal pressure.
A high-speed laryngoscopic investigation of aryepiglottic trilling
Authors: Moisik Scott R. , Esling John H. , Crevier-Buchman Lise
Published: March 2010

Six aryepiglottic trills with varied laryngeal parameters were recorded using high-speed laryngoscopy to investigate the nature of the oscillatory behavior of the upper margin of the epilaryngeal tube. Image analysis techniques were applied to extract data about the patterns of aryepiglottic fold oscillation, with a focus on the oscillatory frequencies of the folds. The acoustic impact of aryepiglottic trilling is also considered, along with possible interactions between the aryepiglottic vibration and vocal fold vibration during the voiced trill. Overall, aryepiglottic trilling is deemed to be correctly labeled as a trill in phonetic terms, while also acting as a means to alter the quality of voicing to be auditorily harsh. In terms of its characterization, aryepiglottic vibration is considerably irregular, but it shows indications of contributing quasi-harmonic excitation of the vocal tract, particularly noticeable under conditions of glottal voicelessness. Aryepiglottic vibrations appear to be largely independent of glottal vibration in terms of oscillatory frequency but can be increased in frequency by increasing overall laryngeal constriction. There is evidence that aryepiglottic vibration induces an alternating vocal fold vibration pattern. It is concluded that aryepiglottic trilling, like ventricular phonation, should be regarded as a complex, if highly irregular, sound source.
Why are natural sounds detected faster than pips?
Authors: Suied Clara , Susini Patrick , McAdams Stephen , Patterson Roy D.
Published: March 2010

Simple reaction times (RTs) were used to measure differences in processing time between natural animal sounds and artificial sounds. When the artificial stimuli were sequences of short tone pulses, the animal sounds were detected faster than the artificial sounds. The animal sounds were then compared with acoustically modified versions (white noise modulated by the temporal envelope of the animal sounds). No differences in RTs were observed between the animal sounds and their modified counterparts. These results show that the fast detection observed for natural sounds, in the present task, could be explained by their acoustic properties.
Aerogels: A “Green” thermo-acoustic insulation material with nanoscale properties.
Authors: Satterwhite James
Published: March 2010

Aerogels are a well-known class of thermal insulation derived from nanoscience that has “green” benefits including translucence, thinness, hydrophobicity, light weight, and flexibility. Recently, the acoustical properties of aerogels have been characterized. Aerogels are currently available in building materials like skylights and exterior glazing, fabrics-based roofing membranes, and flexible blankets for insulating underwater pipelines and building walls. In 2008–2009, laboratory testing and field research began on the acoustical properties of thin profile (2–8-mm) architectural “tensile membrane” fabrics incorporating silica aerogel granules. Data from a tension structure in Canada—where aerogel-enhanced fabric was used to block aircraft noise—exhibited excellent acoustic absorption and acoustic impedance matching properties compared to insulators of comparable thickness. The material increased transmission loss of exterior to interior noise and also reduced indoor reverberation. In the same period, US field tests demonstrated an aerogel blanket material as a surface treatment in open offices to reduce broadband reverberation, resulting in increased speech intelligibility and privacy and enhanced acoustical comfort. These acoustical attributes combined with aerogels’ thermal value, thin form factor, translucence, hydrophobicity, light weight, and absence of VOCs had led to growing interest in green building applications ranging from aircraft interiors to hospitals.
Epidemiology of noise-induced hearing loss.
Authors: Agrawal Yuri
Published: March 2010

Noise exposure is a significant risk factor for hearing loss; recent analyses from a national sample of US adults have shown that occupational and firearm noise exposure increase the risk of hearing loss by 60% and 90%, respectively. Noise trauma typically produces a high-frequency pattern of hearing loss due to hair cell injury in the cochlear base, in contrast to cardiovascular risk factors which appear to cause cochlear damage across the frequency range. Significant interactions between noise exposure and cardiovascular risks have been demonstrated, such that these exposures exert a multiplicative detrimental effect on hearing thresholds. Although exposure to industrial occupational noise may be decreasing in the US population, the rising use of personal listening devices—particularly among children and young adults—is raising concern for a surge in hearing loss prevalence in the younger population. Indeed, recent data from the US population suggest that during the 1999–2004 time interval, significant increases in the prevalence of hearing loss were observed only among young adults. Further longitudinal analyses of children and young adults will be required to better characterize the hearing risks associated with these new forms of noise exposure.
Time-domain numerical simulation of scattering by objects in the seafloor.
Authors: Calvo David C. , Zampolli Mario , Bingham Jill P. , Dey Saikat , Simpson Harry J.
Published: March 2010

Numerical simulation of scattering in the time domain offers potential implementation advantages in comparison with frequency-domain methods. By using explicit numerical time integration schemes, elastic stresses and velocities can typically be advanced using only spatially local information which makes parallelization by domain decomposition straightforward to implement in comparison with the solution of a large linear system of equations. On the other hand, incorporation of frequency-dependent sound speed and attenuation appears more challenging in the time domain with the general need to compute convolutions under non-FFT friendly conditions. This talk presents efficiency gains for the elastodynamic finite integration technique (EFIT) which is similar to the finite-difference time-domain method (FDTD). We present results on using explicit decomposition of scattered and incident wave fields and far-field projection in the time domain with the discrete Helmholtz–Kirchhoff integral. We also present incorporation of frequency-dependent material parameters by efficient recursive convolution techniques that have been used successfully to create time-domain perfectly matched layers [J. A. Roden and S. D. Gedney, Microwave Opt. Technol. Lett. 27, 334–338, (2000)]. As an application example, we present results on computing bistatic target strength variance for a two-dimensional object located near a statistically rough seafloor. [Work sponsored by the Office of Naval Research.]
Testing and modeling of a spiral wave front beacon for use in navigation.
Authors: Dzikowicz Benjamin R. , Hefner Brian T.
Published: March 2010

A beacon with two cylindrical elements of 3-1 composite material has been developed, tested, and modeled for use in navigation. The displacement of each element is radial and the phase of the outgoing wave front is determined by the cross-section of the cylinder. One element, the reference, has a circular cross-section which produces circular wave fronts. The second element has a radius that varies linearly with angle such that there is a displacement of one wavelength over 360 deg; the resulting wave front is spiral. This beacon improves on a prototype presented at a prior meeting [Dzikowicz and Hefner, J. Acoust. Soc. Am. 125, 2540 (2009)]. Results from experiments conducted at the Naval Surface Warfare Center, Panama City Division are compared with finite element models. Surface displacement of the elements is determined by the use of laser Doppler vibrometry. Variation in the field due to geometry and surface displacement variation are discussed. A simple navigational test shows the efficacy of the beacon. [Work supported by the Office of Naval Research.]
Forward scatter and backscatter low-frequency synthetic array measurements of the structural acoustic response from proud targets using a 48-m-long rail in a littoral environment.
Authors: Simpson Harry J. , Waters Zachary J. , Calvo David C. , Houston Brian H. , Berdoz Alain R. , Amon Danial L. , Frank Philip A. , Liskey Steve W. , Kraus Larry A. , Bucaro Joseph A.
Published: March 2010

A series of short range (25-m) forward scatter and backscatter measurements in a littoral environment was conducted to quantify the structural acoustic response from proud targets in the 2–23 kHz frequency band. The water channel was 14 m deep in the Gulf of Mexico near Shell Island, Panama City FL. The bottom was a medium grained sand. The acoustic forward scatter response of the proud targets was measured in a bistatic configuration with the source 25 m from the target and a receiver mounted on a 48-m-long rail. The rail is used to position the receiver and synthetically quantify the structural acoustic forward scatter response. A second source was co-located with the receiver on the rail, and monostatic backscatter measurements were also taken for each target. The structural acoustic response was analyzed and will be reported. The synthetic array experimental results are compared and contrasted with laboratory measurements. The laboratory measurements are convolved with water channel propagation predictions using a parabolic equation model of the littoral environment. The convolved laboratory target strengths compare well with the synthetic array measurements, and a detailed discussion of the comparison will be presented. [Work supported by ONR.]
Scattering experiments for exploring pressure gradient coupling to modes of solid cylinders.
Authors: Marston Timothy M. , Marston Philip L.
Published: March 2010

Grazing illumination of a target close to a flat interface as well as evanescent wave illumination of a buried target can produce significant vertical acoustic pressure gradients at a target. A prior experiment [Espana et al., J. Acoust. Soc. Am. 126, 2187 (2009)] demonstrated the selective coupling to a mode of a flat-ended solid horizontal circular cylinder. The cylinder’s axis was positioned so that the vertical pressure gradient was large at the end of the cylinder. The present investigation explores this coupling for wider variety cylinders in which the end of the cylinder was modified to include a flat paddle. Such a paddle resembles a fin-like appendage. When a flat vertical paddle is subjected to a vertical pressure gradient, the associated torque on the paddle facilitates the excitation of torsional modes of the solid cylinder. The radiation damping is found to increase for larger paddles. Targets modified in this way facilitate the investigation of specific scattering mechanisms. Coupling to this type of mode is suppressed when the cylinder’s axis is at a pressure anti-node where the pressure gradient vanishes. [Work supported by ONR.]
Quantifying the diffuseness of a sound field using a combined pressure and particle velocity sensor.
Authors: Botts Jonathan M. , Robinson Philip W. , de Bree Hans-Elias , Xiang Ning
Published: March 2010

In many areas of acoustics, the degree to which a sound field is mixed, diffuse, or spatially uniform is important in understanding the system. In the case of performance spaces, it influences the audience’s perception of the performance. More generally, it may have implications on the assessment of measurements taken in a space since often the evaluation of room-acoustic measurements relies on diffuse field assumptions. Several techniques have been proposed to quantify the diffuseness in a space, and one of the more recent methods will be investigated in this paper. Signals measured with a combined pressure and particle velocity sensor are used to calculate energy density and average intensity. The degree of diffuseness is then associated with the relationship between these two quantities. This paper discusses aspects of the relevant theory and practical implementation.
Natural modes of vibration in the auditory system of a teleost.
Authors: Schilt Carl R. , Cranford Ted W. , Krysl Petr , Shadwick Robert E. , Hawkins Anthony D.
Published: March 2010

Fishes are diverse in hearing systems and anatomy. Doing actual bioacoustic experiments with even one species, candidate sound, and acoustic environment is difficult to conduct and to generalize. Our modeling approach, if properly carried out and validated, will enable us to do virtual bioacoustic experiments that will enhance knowledge of biophysical phenomena with economy of time and resources. We present preliminary results of a project that extends to fishes our finite-element modeling methods, which have been used to investigate marine mammal bioacoustics. These methods involve obtaining appropriate specimens, scanning them with x-ray CT, measuring elasticity of tissues, and constructing a finite-element model. Then we simulate the interactions between selected anthropogenic sounds and the model of the fish. Here we introduce vibrational analysis with fishes, simulating the resonant frequencies of the otoliths and surrounding structures in a large sciaenid fish (the white seabass, Atractoscion nobilis). Our preliminary analysis indicates the potential for complex relative motions among otoliths and, by implication, their sensory maculae.
Auditory hair cell regeneration in teleost fishes: A review.
Authors: Smith Michael E.
Published: March 2010

Exposure to high levels of sound can cause damage to the auditory hair cells of many organisms, including fishes, resulting in hearing deficits. While such exposure can lead to permanent hearing loss in mammals, other phylogenetically older nonmammalian vertebrates, such as birds, reptiles, amphibians, and fishes, can spontaneously regenerate hair cells in both the vestibular and auditory portions of the inner ear following trauma. The general mechanism of hair cell regeneration is currently being examined in a number of different taxa, but data are limited on hair cell regeneration in the inner ear of fishes. This presentation will summarize the few studies that have examined auditory hair cell regeneration in teleost fishes and compare the results reported for fishes to those reported for other species. While understanding the process of hair cell regeneration in fishes has biomedical relevance, this knowledge could also benefit marine managers attempting to mitigate the effects of anthropogenic noise on fishes. [Work supported by NIH P20 RR16481.]
Noninvasive in vivo cavitation threshold detection during blood-brain barrier opening using focused ultrasound and the contrast agent and definity.
Authors: Tung Yao-Sheng , Vlachos Fotis , Deffieux Thomas , Choi James
Published: March 2010

The in vivo cavitation response associated with blood-brain barrier (BBB) opening as induced by transcranial focused ultrasound (FUS) and microbubbles was studied in order to better identify the underlying mechanism. A cylindrically focused hydrophone, confocal with the FUS transducer, was used as a passive cavitation detector (PCD) to identify the threshold of inertial cavitation (IC) in the presence of definity microbubbles. After definity was injected intravenously, pulsed FUS, with parameters previously shown to generate opening, was applied (frequency: 1.525 MHz, peak-rarefactional pressure: 0.30–0.60 MPa, duty cycle: 20%, PRF: 10 Hz, duration: 1 min) on the right hippocampus of five mice in vivo through their intact skin and skull. T1-weighted MRI was used to verify BBB opening. A spectrogram was generated at each pressure in order to detect the IC onset and duration. The IC threshold detected was 0.60 MPa and mainly occurred during the first 50 cycles. Harmonics were also detected during BBB opening starting at 0.30 MPa indicating stable cavitation occurrence. In conclusion, stable and inertial cavitation could be detected in vivo without craniotomy and IC is not required for BBB opening. [This work was supported by NIH R21EY018505, NIH R01EB009014 and NSF CAREER 0644713.
Building a musical instrument as a laboratory project in a short-term course.
Authors: Morrison Andrew C.
Published: March 2010

In a month-long short course titled “Sound, Music, and Hearing” students were required to design and build their own instruments as a final laboratory project. The assignment requires that the instrument be able to play a scale of a minimum of five notes recognizable to the ear of the instructor. Students were allowed to work in pairs, or alone on the instrument laboratory. A review of strategies for overcoming the challenges of including an instrument building laboratory in a short-term course designed for general education credit is presented.
Homemade musical instruments from Westtown school.
Authors: Feierman Barry, H.
Published: March 2010

Westtown School has implemented a team-taught collaborative class in high school featuring the Music and Science Departments. A new course, The Physics of Sound/Music, aims to teach students about the physics of sound waves and music theory. The course is open to 11th/12th graders and is team-taught by a science teacher and a music teacher. Objective: Each student will demonstrate his/her knowledge through the design and construction of a new, unique musical instrument,write a musical composition to feature the instrument, and play that piece in a student recital. This course is an elective open to students who have already completed chemistry and physics, and appeals to students who would like a creative challenge in terms of both design and construction of a musical instrument. This paper will be to describe the nature of the course, the experience of its two teachers, and to allow some of the students in the class to demonstrate their home-made instruments and talk about their experience. [Westtown School is a K-12 Quaker co-ed boarding school near Philadelphia.]
Contemporary consulting practice in California’s central coast.
Authors: Lord David
Published: March 2010

The resolution of technical, theoretical, and practical issues for a small consultancy in a remote location brings better results and greater satisfaction to all involved. This paper will describe the range of consulting projects encountered in a typical year and will briefly cover the technical tools used and their application to modest-scale residential and commercial development in the Central Coast of California. The acoustics consultant’s responsibility and influence on project development require technical expertise, negotiation, and tailored explanations-on-demand of principles and details to clients, design professionals, builders, and planners as well as interested and sometimes skeptical community groups.
Design and test of a manufacturing building to meet a 40 dB from above 300 Hz up property line night noise limit.
Authors: Campanella Angelo
Published: March 2010

A new one-story manufacturing plant was designed to operate around the clock 7 days a week. Its south property line adjoined existing residential lots. The existing noise ordinance required that the property line noise from the plant shall not exceed 40 dB at all frequencies above 300 Hz at night. The city had already erected an eight barrier mound near that line. Positions of plant air handling HVAC systems were revised to minimize sound emission to the south. Barriers were designed for the outdoor HVAC condensers. The building wall near noisy plant equipment was provided extra attenuation. On commissioning, it was found that a fan needed on the south facade was running above design speed and was readjusted. Sound at the property line was then so quiet compared to the environment that additional monitoring was conducted halfway between the plant wall and the property line. Measurement at the property line was made in 1/3 octave bands, and then parsed to approximate the old octave band limits format to demonstrate compliance.
Influence of various uncertainty factors on the result of beamforming measurements.
Authors: Mller-Trapet Markus , Dietrich Pascal
Published: March 2010

In a previous publication [Mller-Trapet and Dietrich (2009)], a virtual measurement environment for sound-source localization on vibrating structures was presented. Based on surface velocity data obtained from laser-scanning-vibrometry measurements, the boundary-element-method is used to simulate the sound radiation from a vibrating plate toward a microphone array under ideal conditions. The advantage of this approach is that the measurement conditions can be perfectly controlled and real sources can be considered, without restrictions on the type of source. The virtual measurement environment will now be used to investigate the effect of some of the uncertainties that can be encountered during beamforming measurements. For the most common planar array geometries, the beamforming source maps will be calculated for varying signal-to-noise ratios and different array imperfections (uncertainties in the location of the microphones and deviation from the omni-directional directivity pattern of the microphones). As a measure of comparison, the two-dimensional normalized cross-correlation between the ideal source map and the source map with added uncertainties will be evaluated and discussed.
Acoustic measurement in the static firing tests of solid rocket motors.
Authors: Ishii Tatsuya , Oinuma Hideshi , Kazawa Junichi , Fukuda Kota , Tsutsumi Seiji , Ui Kyoichi , Minesugi Kenji
Published: March 2010

Acoustic management is essential for establishing a reliable and cost-competitive rocket system. A solid propellant motor during its lift-off imposes high levels of pressure and vibration on the fairing of the rocket, sometimes leading to crucial damage of the payload. One approach to resolve this problem is to decrease the sound sources caused by high-speed plume of the rocket booster. Japan Aerospace Exploration Agency (JAXA), aiming at the advanced solid rocket, started computational prediction that helps design a launch-pad with less acoustic impact. For validating the computation codes and modeling the acoustic characteristics, the experimental acoustic data of solid rocket motors have long been desired. Fortunately, we had opportunities of the ground firing tests with several motors. In this presentation, the acoustic measurement including the sensors, the set-up, and the data reduction carried out in these tests will be discussed.
Refraction corrections in source localization with an elevated acoustic sensor array in the 2007 Yuma experiment.
Authors: Ostashev Vladimir E. , Reiff Christian G. , Scanlon Michael V. , Collier Sandra L. , Wilson D. Keith
Published: March 2010

Performance of ground based acoustic sensor arrays for source detection is limited by several factors, including sound reflections by obstacles, irregular terrain, multipath sound propagation, absorption of sound waves in the ground, and formation of an acoustic shadow zone in the upwind direction. These shortcomings can be overcome by suspending acoustic sensor arrays below tethered aerostats. A comprehensive experiment in source localization was carried out in October of 2007 near Yuma, AZ. A sensor array was suspended below an aerostat, and ray refraction corrections were calculated for the apparent source coordinates. Significant bias errors in the source coordinates were found if a straight-line approximation for sound propagation in the atmosphere is used. However, by taking into account refraction of sound signals due to vertical profiles of temperature and wind velocity, it is possible to significantly reduce the localization errors even with a rough approximation of these meteorological profiles. If actual profiles were used in refraction corrections, localization errors would probably be further reduced.
Statistical properties of deep ocean noise.
Authors: Moskovitz Brianne , D’Spain Gerald , Hildebrand John , Madduri Achintya
Published: March 2010

The various arrays sea test (VAST) was conducted in July 1989 in the northeast Pacific Ocean. A 3000-m-long, 200-element hydrophone array was suspended for an 11-day period from R/P FLIP, moored about halfway between San Diego and Hawaii (34N, 140W). Simultaneously, 12 neutrally buoyant, freely drifting Swallow floats equipped with both infrasonic hydrophones and three-component geophones were deployed at various depths 150 km off the California coast (35N, 122W). The statistical properties of deep ocean noise recorded by these sensor systems, both single element and beam level, are examined quantitatively under a variety of conditions, including wind-dominated (15–18 kt), distant air gun operations, and marine mammal vocalizations. Non-parametric statistical tests applied to narrow band complex time series of the data include the Wald–Wolfowitz run test for mutual independence of the data samples, the Kolmogorov–Smirnov two-sample test for stationarity, and the Kolmogorov–Smirnov one-sample test for Gaussianity. Results are presented over a broad range in frequencies and time scales and show that the noise field at times and in certain directions displays non-stationary and non-Gaussian properties. In a few cases, these statistical characteristics can be associated with specific physical processes. [Work supported by the Office of Naval Research.]
Horizontal focusing/defocusing due to shallow-water internal waves.
Authors: Luo Jing , Badiey Mohsen , Lin Ying-Tsong
Published: March 2010

During the New Jersey Shallow Water 2006 (SW06) experiment, an acoustic source was towed by the Research Vessel Sharp and followed the front of an internal wave packet. The source was transmitting broadband acoustic signals (50–450 Hz) in different angles with respect to the internal wave front. The receptions of transmitted signal on a vertical hydrophone line array are analyzed to study the horizontal focusing/defocusing that occurred when the internal wave front and acoustic track aligned closely. Based on ship-board radar images and temperature data collected on the environmental moorings at various locations along the acoustic track, a detailed three-dimensional (3D) environment is reconstructed for a 3-D parabolic approximation model to study the unique propagation scenario. Construction of index of normal mode refraction for these data provides a clear picture of acoustic energy focusing for this event. Data and model comparison are in good agreement. [Work supported by ONR321 OA]
From Catgut to the Violin Society of America: The past 10 years of violin acoustics research.
Authors: Tao Fan-Chia
Published: March 2010

In the late 1990s, most of the original founding members of the Catgut Acoustical Society (CAS) had passed away and Carleen Hutchins had departed to concentrate on her new violin octet family. Nevertheless, violin acoustics research continued around the world. In 2002, the CAS and the Violin Society of America (VSA) co-sponsored a violin acoustics workshop at Oberlin College to bring together the world’s leading violin acoustics researchers and violin makers. This annual VSA-Oberlin Acoustics workshop has spawned numerous collaborative projects such as George Bissinger’s Strad 3D project. In 2005, the CAS merged with the VSA to become the CAS Forum. Members of the CAS Forum have continued to promote violin acoustics by organizing workshops, research projects, and presentations at international meetings of violin makers.
Computed cavity-air modes of Le Gruere violin and coupling to corpus modes.
Authors: Gough C. E.
Published: March 2010

The internal cavity air modes of both a normal arched violin with f-holes and Calrleen Hutchin’s Le Gruyère violin with additional holes around the ribs have been computed using COMSOL MULTIDISCIPLINARY ACOUSTICS software. The calculations underpin the need to take finite size corrections into account when evaluating the acoustically important Helmholtz or A0 air resonance. The computed modal shapes and frequencies are compared with the assumptions and predictions of the Shaw two degrees of freedom network model. This has been widely used to interpret the dependence of the A0 and A1 resonant frequencies on both cavity volume and the number of additional holes opened around the ribs. Finite size effects are shown to have a marked influence on such dependencies. They are shown to result in marked deviations from predictions based on an ideal Helmholtz resonator. The coupling of the air modes to the corpus modes that excite them is considered using a simple dynamic model. The pedictions of the model are compared with those of the Shaw network model and measurements of the dependence of A0 and A1 mode frequencies on the number and placing of additional holes opened around the ribs of the Le Gruyère violin.