bluuebunny/crossref_metadata_2025 huggingface dataset:
Buccal stone whistles of the Mixtec Region, Oaxaca, Mexico.
Authors: Sanchez Gonzalo
Published: October 2010

The buccal stone whistles of this paper were documented by an archaeologist in the site Cerro de las Minas (Hill of the Mines), localized in the Mixtec Region, at Norwest of Oaxaca State, Mexico. These aerophones belong to the singular family of ancient noise generators that were used by several Mesoamerican cultures, but they are the unique case of documented buccal stone whistles from the Oaxaca area. The paper presents the preliminary results of the organological and acoustical study applied to the set of whistles from Cerro de las Minas. They are extraordinary because they were made of stones or rocks; the sonorous mechanism (mouth-whistle system) and his operation and generated noise are complex; they are not included in the existing organological classifications of musical instruments; and very few papers are known on the acoustics of this kind of ancient whistles.
Death whistle.
Authors: Velazquez Roberto , Rivas Castro Francisco
Published: October 2010

The extraordinary death whistle was exclusively used in several zones of ancient Mexico and belongs to a very singular family of Mexican resonators that are not well known and can produce special sounds imitating animal calls and noise of the wind. It is not a common whistle or musical instrument. It has been associated with rituals of death by its decorated face of a skull and with the wind because two of them were found in the hands of a sacrificed man skeleton in front of the Ehecatl temple at the Tletelolco archaeological site. Its archaeological context and iconography are associated with two divine concepts of the ancient Mexican mythology: Ehecatl (wind) and Mictlantecutli (death). The study was initiated with the direct analysis of a fragment of clay whistle from the Mazatepetl (deer hill in the south of Mexico city). Some examples of buccal noise generators that were analyzed and identified by the author are presented. Morphology and acoustic characteristics of death whistle and its sounds are discussed, and the main information and available data on the fragment found on the Mazatepetl as well as its procedure of construction and probable uses of its sounds are also discussed
Bell stone at Xolotl hill.
Authors: Beristain Sergio , Rivas Castro Francisco , Velazquez Cabrera Roberto
Published: October 2010

This paper is about a bell stone located in the middle of the ancient Xolotl hill, known as the first Xolotl Chichimeca capital city by the 1200 AD. This low profile hill is located nearby San Lucas Xolos town at Tizayuca County, Hgo. This basalt rock is known as having some cultural work, expressed as the archaeological concept “pocitas.” Local people tell histories, where these kinds of rock are addressed as “bell sounding stones” when they are stricken by another stone, inside the “pocita.” This is an example of those mentioned in some other Mesoamerican archeological sites references.
Analysis of a pressure equalized rainscreen wall as a periodic array of Helmholtz resonators.
Authors: Muehleisen Ralph T.
Published: October 2010

One of the primary purposes of the building enclosure is to separate occupants from the natural elements such as rain and snow. Water can penetrate this enclosure through four primary mechanisms: air pressure differences between interior and exterior, rain drop momentum, surface tension, and capillary action. The pressure equalized rainscreen (PER) wall is a two layer wall construction that places a vented cavity between an inner wall and outer cladding. When properly designed, the cavity pressure equalizes to that of the external wind on the building, keeping rain from entering the cavity by air pressure differences and the cavity space eliminates momentum, surface tension, and capillary action as water transport mechanisms. A typical building using PER walls will have a large number of these cavities with a regular spacing. In this paper the wind response of the PER wall will be analyzed as a periodic array of Helmholtz resonators exposed to periodic excitation.
Speaker identification: Effects of noise, telephone bandwidth, and word count on accuracy.
Authors: Cassie Dallasarra , Aericka Dunn , Shanna White , Al Yonovitz , Herbert Joe
Published: October 2010

It is of great interest by the legal system to identify individuals by their voice. Controversy in this area has continued for nearly five decades with states divided with regard to the merits of voice identification. The American Board of Recorded Evidence [ABRE (1999)] has established standards for the determination of identification or elimination of speakers. Digital spectrographic techniques, including formant tracking and finer descriptive measures of speech, are dramatic improvements and allow a test of the ABRE standards using improved technology embodying similar principles set forth in an aural and spectrographic method. Ten speakers recorded synthetic sentences at two different times. Words were distorted by mixing with noise or by telephone bandwidth reduction. All possible speaker pairs of “elimination” were presented to qualified listeners as well as equal probability of “identification.” For the comparison, subjects were presented spectrograms, formant tracks, fundamental frequency, and the ability to listen to single words. Confidence ratings and determinations (elimination or identification) for each comparison word were made with the addition of added words(<20). The results will be discussed with regard to correct classification based upon the number of words required and the reduction of correct classification based upon the distorted conditions.
The fine structure of phonation as a biometric.
Authors: Disner Sandra Ferrari , Fulop Sean A. , Hsieh Fang-Ying
Published: October 2010

The reassigned spectrogram, an enhanced time-frequency display that has been proposed as a means of focusing in on the details of the phonation process [S. A. Fulop and S. F. Disner, “Advanced time-frequency displays applied to forensic speaker identification,” J. Acoust. Soc. Am. 125, 2530 (2009)] was used to examine a set of sustained vowels produced by 16 speakers of American English. Certain characteristics, such as the relative amplitudes of the formants, the presence or absence of a so-called “voice bar,” and evidence of secondary excitation within a single glottal period, appear to be rather stable across repetitions of the same vowel by the same speaker, but divergent across speakers. The possibility of this method being used to corroborate conventional methods of forensic speaker identification is thus afforded a measure of support.
Statistics of mode amplitudes in an ocean with random sound speed perturbations: Temporal coherence.
Authors: Colosi John A. , Chandrayadula Tarun K. , Voronovich Alex G. , Ostashev Vladimir E.
Published: October 2010

A transport equation has been derived to describe the range evolution of the single frequency cross mode coherence matrix including time separations. The theory assumes 2-D propagation in the depth range plane, small angle, weak multiple forward scattering, and the Markov approximation, and it has been shown to accurately predict the observable of mean intensity for both deep and shallow water (i.e., strongly lossy) situations. This paper will present results for the acoustic observable time coherence and will address the issues of accuracy of the temporal coherence approximations, relative contributions from coupling and adiabatic effects, scaling with range and frequency, and the functional form of the coherence with regards to lag.
Three-dimensional modal theory of sound propagation in a fluctuating ocean with spatial-temporal inhomogeneities.
Authors: Voronovich Alexander G. , Ostashev Vladimir E. , Colosi John A.
Published: October 2010

A 3-D modal theory of sound propagation in an ocean with spatial-temporal random inhomogeneities in the sound speed is developed. Closed-form equations for the second-order statistical moments of broadband acoustic signals are derived. Interaction of acoustic modes with the ocean surface and bottom is ignored so that the theory is particularly useful for low-frequency, long-range sound propagation. The theory developed is applied to studies of temporal coherence of narrowband acoustic signals propagating in a fluctuating ocean perturbed by linear internal waves with the Garrett–Munk spectrum. It is shown numerically that for the fixed range, the coherence time of acoustic signals is inversely proportional to the sound frequency; for the fixed frequency, the coherence time is inversely proportional to the square-root of the propagation range. These results are consistent with experimental data and are similar to those obtained with the path-integral approach. The latter approach predicts the coherence time for an individual ray path while the 3-D modal theory predicts it for superposition of acoustic modes, e.g., the total acoustic signal. [Work supported by the Office of Naval Research.]
Quantifying the contamination of natural low frequency ambient noise in the oceans by distant and pervasive anthropogenic airgun signals.
Authors: Jain Ankita D. , Jagannathan Srinivasan , Makris Nicholas C. , Uribe Arturo C.
Published: October 2010

Periodic seismic airgun pulses have been shown to be present throughout much of the year in low-frequency underwater ambient noise measurements in deep water environments of the North Atlantic Ocean. [Nieukirk et al., J. Acoust. Soc. Am. 115, 1832–1843 (2004).] Recently, we recorded low-frequency noise over a period of 1 year in the Pacific Ocean, off the coast of Isla Socorro, and found similar airgun contamination. Here we show that during periods when periodic airgun contamination exists, it is still possible to extract information about natural geophysical noise by analyzing time series in between airgun pulses, performing spectral analysis, modeling airgun source transmission through the ocean, and correlating measured noise with local wind speed.
Perceptions of auralization in the design process.
Authors: Philipp Norman H.
Published: October 2010

The application of auralization as a part of the architectural design process first requires an understanding of the current perceptions of auralizations by the design community. From this inquiry on a national scope, the level of education necessary to allow architects to understand auralizations and embrace them into their design processes may be determined. This paper summarizes the preliminary phases in the development of a national survey toward the aforementioned goals.
Combining auditory and tactile inputs to create a sense of auditory space.
Authors: Deas Ross W. , Adamson Robert B. , Garland Philip P. , Bance Manohar , Brown Jeremy A
Published: October 2010

To localize a sound, the auditory system uses multiple cues, including binaural differences in timing and level that arise from the separation of the ears by the solid mass of the head. It has repeatedly been shown that the ability to utilize these cues is plastic and experience-based. Vibrotactile input shares many common features with auditory signals, and there is some overlap between the frequency range of the sensitivity of the ear and skin. In this study, we examine whether the auditory system is capable of combining auditory and tactile inputs to localize sounds using a multi-speaker array. To induce deficits in azimuthal localization, one ear was plugged. To examine cross-modal localization, the input level to the plugged ear was recorded via microphone, and a vibratory signal that was perceptually equal in intensity was presented to the shoulder on the same side as the plugged ear. The participant’s ability to localize low-pass, band-pass, high-pass, and broadband sounds was measured. Results showed that relative to baseline (plugged) conditions, localization performance improved, suggesting that listeners can combine auditory and tactile information to create a sense of auditory space.
Correct and rapid impulse response calculation as a precondition for auralization.
Authors: Ahnert Wolfgang , Feistel Stefan , Miron Alexandru
Published: October 2010

For almost 20 years auralization procedures have become more and more common, but the simulated acquisition of needed impulse responses (IRs) is still a crucial point during a design process. Different methods have been developed over time with different assumptions and approximations. Until now we observe time-consuming procedures to calculate true IRs especially in large halls. In this paper new algorithms are reported to calculate IRs in multi-thread mode with one computer or better via a network with a set of CPUs working in parallel. So calculations in large halls may be reduced from 8–10 h with one CPU to 10–20 min with multi-core computers. Via internet routines a master-slave network is used to allow parallel networking on the same file. Examples are shown using eight remote-controlled quad-core computers, i.e., 32 CPUs at the same time. This way the auralization procedure is becoming a daily and quickly usable function. It opens the way to convert an auralization toy into a real tool.
Modal reverberation time in acoustic systems with absorptive walls.
Authors: Mollinedo Helvio , Merodio Hector , Rabadan Itzala , Ortega Jose Angel
Published: October 2010

The early works about the reverberation of room acoustics start with geometrical tecniques. Subsequent works in this field showed that the reverberation has characteristic frequencies of the normal vibration modes of the room, and not necessarily the frequency of the source that starts the vibration; the acoustic response of the room can be understood in terms of normal modes and the decay coefficient associated with each one of those modes. This work presents an analysis of a known procedure to compute the decay coefficient and the modal reverberation time of interior acoustic rooms with lightly damped absorptive walls by means of the finite element method. This procedure was performed for several wall-lined configurations in 3-D geometries. These calculations were carried out in a computational program prepared in MATLAB. The results show how this useful technique could predict the modal response and reverberation time depending on the absorption wall configuration.
Case studies of bioacoustics research in Brazil.
Authors: Sousa-Lima R. S.
Published: October 2010

Brazilian researchers have a growing interest in animal sounds as more and more exposure is given to this subject in the worldwide literature and concerns about noise pollution are on the rise. Some case studies focusing on research that I have been involved in, i.e., studying manatees (Trichechus inunguis and T. manatus), humpback whales (Megaptera novaeangliae), manned wolves (Chrysocyon brachyurus), primates (Callitrix penicillata), and fish (Prochilodus sp. and Leporinus sp.), will be presented. Studies of the acoustic ecology of these species have focused on determining the importance of acoustic communication, vocal identity, and differences in the acoustic behavior of groups of animals to better understand animal populations in the wild and in urban areas. Such studies help to support overall conservation efforts and highlight the importance of the potentially negative effects of masking on animal communication systems in the tropics.
A comparison of acoustic soundscapes within and among three tropical habitats: Can soundscape heterogeneity be used as an index of alpha diversity?
Authors: May-Collado L. J. , Aide T. M. , Corrada C. , Alvarez R.
Published: October 2010

Rapid biodiversity assessment methods are needed to ensure that adequate policies and management strategies are established to protect biodiversity. In this study, we evaluate the reliability of a recently developed acoustic index for alpha diversity by determining the within and among site variations from three permanent automated recording stations located in Sabana Seca (wetland) and El Verde (moist forest), Puerto Rico and in La Selva (wet forest), Costa Rica. All stations sampled the soundscape for 1-min every 10-min, 24 h per day throughout the year. For this analysis, we evaluated recordings from the dry season and wet season for each site. The analyzes were carried out on each individual recording and then mean values were calculated for each month. Independent of the season or time, La Selva had the highest acoustic diversity and El Verde had the lowest. Both Sabana Seca and El Verde showed a significant increase in acoustic richness after dusk, reflecting the peak of amphibian activity. This acoustical index is a useful tool for identifying important areas of biodiversity without relying on individual species identification. Our results indicate that soundscape heterogeneity is a good indicator of alpha diversity.
The role of the environment on the acoustic radiation patterns of mating calls of the túngara frog.
Authors: Bernal Ximena E. , Page Rachel A. , Ryan Michael J. , Argo Theodore F. , Wilson Preston S.
Published: October 2010

The present work is a follow-up to previously reported [J. Acoust. Soc. Am. 122, 2981(A) (2007)] laboratory measurements of both the horizontal and vertical frequency-dependent directivity of the mating calls of túngara frogs, Physalaemus pustulosus. Band-limited directivities are significantly greater than broadband directivities, with a maximum directivity of 20 dB in the vertical plane for harmonics near 6 kHz. This result is unexpected given that female frogs, the intended receivers of this call, are on the horizontal plane rather than on the vertical plane where unintended receivers (predators and parasites) reside. New numerical finite element modeling of the radiation, including the effects of the environment, will be reported. Túngara frogs only call while partially submerged in water. Modeling results indicate that the reflecting boundary provided by a finite-sized air-water interface dominates the radiation, and results in the observed directivity. There is comparatively little directivity dependence on the nature of the surrounding terrain, be it acoustically hard or soft, smooth or rough. These modeling results indicate that the radiation patterns found in laboratory measurements, although unexpected, are likely to be found in nature too.
Real time two-dimensional temperature imaging for guidance and monitoring of high-intensity focused ultrasound beams.
Authors: Liu Dalong , Ballard John R. , Haritonova Alyona , Jiang Jing , Bischof John C. , Ebbini Emad S.
Published: October 2010

We have recently introduced a fully real time 2-D temperature imaging system using diagnostic ultrasound. A SonixRP is used to collect beamformed M2D mode data with frame rates in the 200–400 fps during the application of pulsed high-intensity focused ultrasound (pHIFU). M2D mode is a modification on the SonixRP allowing for maximizing the number of scanlines per frame for a specified frame rate. This allows for capturing the full range of tissue motions during the application of the pHIFU beams, including native motions due to breathing and pulsations, radiation forces due to pHIFU, and temperature-induced strains. In this paper, we demonstrate the use of this image-guidance mode in the control of the pHIFU exposure in real time with millisecond temporal resolution. Results from heating and lesion formation experiments in the hindlimb of nude mice in vivo will be presented. Temperature imaging results during the application of subtherapeutic pHIFU beams before therapeutic pHIFU lesion formation will demonstrate the advantages of this approach in the guidance and dose estimation. In addition, temperature imaging of subtherapeutic pHIFU after lesion formation allows for the measurement of changes in tissue properties that may be used as indicators of irreversible tissue damage.
Monitoring temperature elevations in tissues using quantitative ultrasound.
Authors: Ghoshal Goutam , Oelze Michael L.
Published: October 2010

High intensity focused ultrasound (HIFU) is a noninvasive technique that has great potential for improving thermal therapies but requires accurate monitoring of lesion formation. Quantitative ultrasound (QUS) is a novel imaging technique that can improve monitoring of HIFU treatment by quantifying tissue changes. Ultrasonic backscatter experiments were performed on tissue-mimicking phantoms, fresh rabbit liver, and beef liver samples versus increases in temperature from 37 to 50 °C in 1 °C increments. Two parameters were estimated from the backscatter coefficient [effective scatterer diameter (ESD) and effective acoustic concentration (EAC)] and two parameters were estimated from envelope statistics (k parameter and μ parameter) of the backscatter. No significant changes in ESD were observed for the phantoms but the ESD increased by more than 10% with increasing temperature in the liver samples. Significant decreases in EAC of 20%–40% were observed in all the samples. No specific trends were observed in envelope statistics versus temperature. From the results, it was observed that some QUS parameters were more sensitive to lesion formation than others. The results suggest that QUS has the potential to be used for noninvasive monitoring of lesion formation because QUS may be sensitive to tissue microstructure changes. [Work supported by NIH R01EB008992.]
Perfluorocarbon nanoemulsions as contrast agents for imaging and ultrasound-mediated targeted chemotherapy.
Authors: Rapoport Natalia
Published: October 2010

During the last decade, achievements of nanomedicine have made possible image-guided drug targeting to disease sites. In oncology, tumor targeting of chemotherapeutic agents can be realized by drug encapsulation in nanocarriers such as liposomes, polymeric micelles, nanoemulsions, etc. A degree of tumor targeting may be increased by developing stimuli responsive nanocarriers that release their drug load in response to external stimuli such as heat, light, or ultrasound. Using ultrasound allows combining imaging and therapy. However, many mechanistic aspects of the ultrasound-mediated drug delivery remain elusive. Which mode of ultrasound, mechanical or thermal, is optimal for drug delivery? Which is the optimal timing of ultrasound application in relation to drug injection? What would be the best target for molecularly targeted carriers? These problems will be discussed for paclitaxel-loaded perfluorocarbon nanoemulsions that manifest a unique combination of properties (acoustic droplet vaporization, cavitation-induced drug release, ultrasound and 19F MR contrast, excellent therapeutic effectiveness). Drug carrier biodistribution was monitored by ultrasound and 19F imaging. Focused ultrasound treatment of red fluorescence protein (RFP) transfected orthotopic pancreatic tumors proceeded under the control of MR thermometry. RFP imaging allowed visualization of ultrasound beam traces and treatment results. [Work supported by NIH R01 EB001033.]
Coupling between air column and structural vibrations in the flaring bell of brass wind instruments.
Authors: Kausel Wilfried , Moore Thomas R.
Published: October 2010

The effect of wall vibrations on the radiated sound of wind instruments has been under debate for quite a long period of time now. Experiments with brass wind instruments like trumpets and horns have shown that this effect is much more pronounced in the steeply flaring bell than in a cylindrical tube. A theory for the coupling between air column and structural oscillations is presented and applied to the flaring bell of brass wind instruments. It will be shown that the effect of a finite Young’s modulus of the wall material on the radiated sound becomes more significant when the flare of the bell is steep. Theoretical predictions for input impedance and sound pressure transfer function are in agreement with measurements made on real instruments. The theory is also extended to the case of randomly broken axial symmetry, a realistic assumption if hand-made thin walled brass instrument bells are taken into consideration. Under the assumption of 0.5% radial deviations from a perfectly circular cross-sectional shape, breathing modes become one order of magnitude more effective than without pre-deformations. It is also shown that purely elliptical pre-deformations are much less effective in modifying air column characteristics than randomly distributed deformations.
Player-to-player variability of the dependence of brass-instrument timbre on bell alloy.
Authors: Pyle Robert
Published: October 2010

Previous measurements showed a substantial difference between two trombone players, call them player A and player B, in the degree to which the radiated spectrum changed with changes of bell alloy. [J. Acoust. Soc. Am. 125, 2597 (2009).] Player A maintained a much more consistent timbre across changes of bell alloy than did player B. It is hypothesized that player A altered his embouchure to offset the effects of changes in the instrument to a much greater extent than did player B. This will be tested by simultaneous measurement of sound pressure internally within the mouthpiece and externally on the bell axis. If the hypothesis is true, changing the bell alloy should be reflected by a greater change in the signal within the mouthpiece cup for player A than for player B. Additional tests are planned with instrument-to-player feedback disturbed by shielding the player’s ears and introducing masking noise.
Measurement of the contribution of each individual vehicle to the road traffic noise.
Authors: Ibarra David , Cobo Pedro , Bravo Teresa
Published: October 2010

Road traffic is the main noise source in urban environments. While it is feasible to measure the noise emitted by road vehicles in standard conditions [ISO 11819-1;2, ISO 362], nowadays it is not possible to detect the contribution of each vehicle to the overall road traffic noise in real driving conditions. However, some authors have demonstrated previously that there is a high correlation between maximum noise levels and mean annoyance. Therefore, an efficient control procedure to reduce road traffic noise annoyance should be to identify those vehicles contributing with the maximum noise levels. The main goal of this paper is to describe a boarded acoustic system to measure the contribution of each vehicle to the overall road traffic noise. The system consists of two microphones, one close to the tire furthest from the exhaust duct, and the other close to the engine air intake. The signals picked up by these microphones are processed to calculate the evolution of the Leq,1s and the levels histogram along the driving path. The tests carried out in an urban circuit in Madrid (Spain), with two cars (gasoline and diesel) and five drivers, demonstrate that it is possible to detect those especially noisy vehicles.
Results and methodologies of airport noise studies.
Authors: Glisser Max J. , Gerard Christian E.
Published: October 2010

Some 7 years ago, Control Acustico Company is working on surveys to get information on noise levels generated by airplane operation at airports, both in Chile and abroad. These surveys included Chilean airports such as Arturo Merino Benítez in Santiago, Maquehue in Temuco, Carriel Sur in Concepción, El Tepual at Puerto Montt, Mataveri at Eastern Island, and Espanol in Barcelona, Spain. This paper displays some results of these surveys using the software Integrated Noise Model from the Federal Aviation Administration, discusses methods used to obtain curves of equal sonority of YLDN, among them measuring of 24 h, or longer, continuous sound pressure levels, and shows an analysis allowing to calibrate the models, fleet structure, approaching and take-off pathways, and finally results evaluation according to the North American Rules, FAR, Chap. 150, “Airports Noise Compatibility Plan.”
Comparison of noise emissions from in situ measurements construction projects in chile with those from British Standard BS 5228-1:2009.
Authors: Glisser Max J. , Gerard Christian E.
Published: October 2010

A large number of noise impact studies for projects of different types are developed annually as part of the System of Environmental Impact Assessment in Chile. One of the most important variables to predict the emission of noise is the sound power of noise sources involved. In this study, we compare sound power levels (Lw) calculated according to measurements of sound pressure levels by the Acoustic Control Company in different construction projects and the levels calculated from the British Standard BS 5228-1:2009 “Code of Practice for Noise and Vibration Control on Construction and Open Sites Noise”. The study considers the most frequently involved machines in construction tasks, such as loader trucks, cement mixer trucks, wheeled loaders, rollers, angle grinders, cranes, circular saws, and backhoes.
Development and calibration of an acoustic model for a mixed residential-industrial zone.
Authors: Cortínez Víctor , Sequeira Martín , Azzurro Adrián , Ponds Facundo
Published: October 2010

This paper deals with the noise characterization of a residential mixed area, originating from stationary industrial sources of a petrochemical establishment in the city of Bahía Blanca. The sound power levels are estimated from a set of acoustics measurements and a subsequent implementation of a method similar to that proposed in the ISO 8297 standard. Later, an outdoor sound propagation model is developed and calibrated by using measurement data located near the urbanized sector. The objective of this work is to provide a useful prediction tool of the noise impact on the nearby residential area and to study possible acoustic treatments in order to plan a suitable urban scenario according to local legislation.
Comparative study of levels of care in children exposed to environmental noise on three campuses in the city of Guadalajara, 2009.
Authors: Preciado Caballero N. , Orozco Medina M. , Figueroa Montaño A. , Ruvalcaba M.
Published: October 2010

Noise is a pollutant that significantly affects the quality of life and health of individuals. Individuals exposed to noise may experience stress, discomfort, sleep disturbances, impaired immune system, lack of alertness, hearing loss (to varying degrees), cardiovascular disease, increased aggressiveness of individuals, low productivity, and traffic and workplace accidents. [WHO (1999); Berglund and Lindvall (1995); Clark et al. (2006); Haines et al. (2001)]. In the city of Guadalajara, a large number of schools are located on heavy traffic roads or busy streets, or in hot spots of environmental noise caused by motor vehicles, which exposes children and teachers who attend them to unfavorable acoustic conditions to develop their school tasks. Thus having a negative effect on their attention span, memory, and performance, as well as damaging physical and emotional health. This study aims to contribute to the study of sound quality by means of the analysis of noise conditions at elementary schools, which were located at critical points in terms of heavy vehicular flow. Besides, it analyzes the perception of environmental noise within the same facilities, and how this compares with results from schools located in quiet streets.
Music and noise.
Authors: Martinez Leal Ricardo , Elizondo-Garza Fernando J.
Published: October 2010

Although the noise takes part in sonorous rites from antiquity, the development of the concept of harmony, which allowed the development of occidental music as art, initially left the noise outside music. From conceptual reviews and the modern music theory, the functions of noise in the sonorous arts were rediscovered and its use received a strong impulse—through electroacoustic music and other artistic tendencies intended to produce reactions on a wide sense on listeners—when intentionally included as noise in the “musical” production. In this paper a historical review of the relation between music and noise with emphasis on the conceptual progresses on the last two centuries is done.
Resonance ultrasound spectroscopy: Highlights of the mathematics.
Authors: Heyliger Paul , Ledbetter Hassel
Published: October 2010

We highlight the key mathematics associated with resonance ultrasound spectroscopy (RUS). From the physics viewpoint, RUS is part of the general problem of elastic vibrations in continuous media. A solid can transmit three waves: one quasilongitudinal and two quasitransverse. At resonance, we see standing waves, which we can represent by an eight-summation Fourier-series wave function. We begin by reviewing briefly the 1-D vibrating-string problem that arose in the music of many early civilizations (about 4000 BC). Pythagoras of Samos (582–507 BC) first treated this problem mathematically. In the early beginnings of modern science, both Galileo (1564–1642) and Mersenne (1588–1648) considered vibrating strings, which have a perfect analog in axial-bar vibration. Lamb and Lamé contributed in the 1800s. Probably the first inverse RUS measurement came from Cole and Frazer (1964), who studied the sphere-vibration problem using graphical methods. Most of our talk will highlight the remarkable mathematical contributions by Demarest (then at Reed College), Ohno (Ehime University), and Visscher (Los Alamos National Laboratory) in considering anisotropic vibrations of unusual-shape solids.
On complications associated with measuring the piezoelectric properties of relaxor single crystals with high electromechanical coupling using resonant bar samples and comparison with a lumped parameter method.
Authors: Brown David A. , Bachand Corey L. , Aronov Boris S.
Published: October 2010

The development of relaxor single crystal piezoelectric materials with exceptionally high electromechanical coupling (k above 0.85) and high elastic and piezoelectric anisotropy presents challenges and questions to the applicability of the use of traditional resonant bar methods (IEEE Standard on Piezoelectricity, 176-1987, Sec. 6.4) for determining the constituent piezoelectric properties. Standard bar techniques for determining coupling coefficient rely on the single degree of freedom electromechanical circuit models for sufficiently long samples whereby measurements of isolated resonances and antiresonance frequencies are uncorrupted by lateral resonances. The limited applicability of the standard method for these piezoelectrics has motivated the development of an alternative method that avoids many of the previous short comings. A lumped parameter dumb-bell resonator approach was implemented by employing a small single crystal piezoelectric sample sandwiched between reactive terminations whereby the piezoelectric and elastic properties may be determined. Coupling coefficients k-33 and k-31 as high as 0.88 were measured for single crystal CPSC160-95 and CPSC180-120 by Ceracomp.
Resonant acoustic spectroscopy of the fluid saturation effects in a carbonate rock.
Authors: Averbach Vyacheslav , Bredikhin Vladimir , Lebedev Andrey , Manakov Sergey
Published: October 2010

We present the results of the acoustic spectroscopy of a carbonate sedimentary rock under various saturation degrees. The data for the same sample were obtained both for elasticity and dissipation tensors within the 2-octaves frequency range. High accuracy of acoustic measurements allowed distinguishing all three stages in the saturation process: condensation, meniscus creation, and filling the pore space with fluid. Both dry rock parameters and the variations observed are in a good agreement with standard granulometry and chemical analysis. Simple estimations of the relative changes in elastic moduli enable clear explanations of these changes observed. The alteration in the frequency dependence of attenuation coefficient allowed proposing reasonable dissipation mechanisms in porous media that can also be useful in the acoustics of ocean sediments.
Resonant ultrasound spectroscopy of complex vanadium spinel oxides.
Authors: Keppens Veerle
Published: October 2010

Complex behavior in spinel oxides is primarily due to the geometry of the pyrochlore sublattice. Spinel vanadates AV2O4 are of particular interest, as they exhibit an additional degree of freedom due to orbital degeneracy, and the physics of these materials is expected to involve an interplay between spin frustration, collective Jahn–Teller effects, and the relativistic spin-orbit interaction. We report here a systematic study of the elastic response of vanadium spinel oxides, where the A cation is Zn2+, Fe2+, or Mn2+. ZnV2O4 is characteristic of the entire series and has received extensive theoretical attention. All V-spinels are cubic at room temperature, but as the materials are cooled, they undergo structural and magnetic phase transitions that are currently the subject of intense experimental and theoretical interest. Resonant ultrasound spectroscopy was used from 2–400 K and in magnetic fields up to 9 T to obtain the elastic moduli. The temperature-dependence of the moduli is found to strongly reflect the structural transition, as large softening is observed when the transition temperature is approached. In the case of MnV2O4, measurements in magnetic field reveal an additional feature near 50 K, which could represent a striking manifestation of direct spin-orbit coupling. [Work supported by NSF-DMR-0804719.]
Under what conditions can non-uniformly spaced stimulation enhance auditory sensitivity? An investigation using time-resetting maps.
Authors: O’Gorman David E. , Colburn H. Steven
Published: October 2010

Most cochlear implants excite auditory nerve fibers with electric current pulses that are uniformly spaced in time. Yet, studies of the vesicle release properties of the ribbon synapses present at the inner hair cell show that temporal spacing of vesicular release is not uniform in time. It is possible that this non-uniform excitation contributes to the high sensitivity and temporal responsiveness of the healthy auditory system and that restoring this feature to the deafened nerve via electrical stimulation would be beneficial. This study uses time-resetting maps, computed from Hodgkin–Huxley-type models, to analyze the conditions under which a non-uniform periodic pulse train, consisting of an alternating sequence of short and long intervals, produces higher modulation sensitivity than a uniform pulse train of the same average rate.
Acquisition of spatial hearing abilities in two-year-old children: Role of auditory experience and bilateral cochlear implantation.
Authors: Litovsky Ruth , Harris Samantha , Born Melissa
Published: October 2010

Bilateral cochlear implants (CIs) are being provided to a growing number of young children to improve spatial hearing and speech understanding in noise. While outcomes and benefits in older bilateral CI users have been documented, little is known about spatial hearing in 2–3 year olds. We studied sound localization abilities in two groups of children: normal hearing children and deaf children, who are fitted with bilateral cochlear implants. A novel task was implemented, whereby children were trained to reach for sounding objects that are hidden behind acoustically transparent curtains as a means of indicating where they perceived the sound to be coming from. Loudspeakers were positioned at ±60, ±45, ±30, ±15, and 0 deg in the horizontal plane. Two tasks were used: (1) left versus right discrimination for each pair and (2) sound localization using the 9-loudspeaker array. Results will be presented for conditions in which stimulus levels were either fixed at 60 dB sound pressure level or roved to minimize monaural level cues. In addition, the effect of auditory experience on performance will be shown for the CI users. Results consist of sound localization accuracy, quantified by the deviation of the reach from the actual source location.
Effect of acoustic-phonetic and semantic enhancements on speech recognition for children with cochlear implants.
Authors: Smiljanic Rajka , Sladen Douglas
Published: October 2010

With early implantation and intense rehabilitation, children with cochlear implants are able to develop high levels of speech understanding in quiet. However, speech recognition in noise remains a challenging task for this listener group. In this study, we examine how signal clarity interacts with the use of compensatory information at higher levels in determining speech recognition levels for children with cochlear implants and children with normal hearing. Specifically, we explore the effect of clear speech, a distinct, intelligibility-enhancing speaking style, and of contextual-semantic information on speech recognition in noise. One hundred and twenty sentences in which final word varied in predictability, i.e., high versus low semantic context, and which were produced in conversational and clear speech by one female and one male talker were embedded in noise. Twenty children between 5 and 12 years of age participated in a sentence-in-noise perception test. The goal was to examine the level of signal clarity needed to take advantage of the contextual information for children with cochlear implants compared to children with normal hearing. This research will allow us to explore the interaction between lower-level sensory and higher-level cognitive factors that affect speech processing in these two target groups of children.
Duration of point vowels in four- and five year olds with hearing aids and cochlear implants.
Authors: VanDam Mark , Ide-Helvie Dana , Moeller Mary Pat
Published: October 2010

Advances in hearing science have dramatically reduced the age of identification of hearing loss (HL) and improved intervention strategies, especially amplification methods. As a result, children with HL have earlier, better auditory access. How this early auditory experience affects language and speech abilities is not fully understood. This study addresses one aspect of speech production looking closely at point vowel duration. Although typically longer in children with HL and younger children, vowel duration has not been examined in early identified children with HL, and possible influence of device type (cochlear implant or hearing aids) is unclear. This study examines point vowel duration at four- and five-year-olds among children with normal hearing, cochlear implants, and hearing aids. Children produced /æ, ɑ, i, u/ in words modeled by the experimenter in a live-voice, listen-and-repeat format. As expected, results indicate that children with HL and younger children produced longer vowels. Results also indicate that effects are likely driven by high vowels in all children, and children with cochlear implants and hearing aids perform similarly, despite less auditory experience in the group with cochlear implants. Results have implications for developmental models and possible clinical applications. [Work supported by NIH/NIDCD Grant Nos. T32-DC00013 and R01-DC006681.]
A lumped parameter mechanical model of tensor tympani muscle contraction of the middle ear.
Authors: Garland Philip P. , Makki Fawaz M. , Deas Ross W. , Adamson Robert B. , Brown Jeremy A. , Bance Manohar L.
Published: October 2010

The role of the tensor tympani (TT) muscle of the middle ear is not well understood, and there is a long history of the implied, but unproven, part it plays in various inner ear disorders, particularly Meniere’s disease. In order to gain an improved understanding of the effect of TT contraction, a lumped parameter mechanical model of the middle ear including the TT has been developed. This model uses a previously developed lumped parameter model of the middle ear ossicular chain along with experimentally obtained visco-elastic material model for the TT in order to predict the changes in the acoustic impedance of the middle ear experienced when the TT is contracted. Qualitatively, the results of the computer model agree quite well to similar laser Doppler vibrometer measurements from various cadaveric temporal bones where TT contraction has been simulated using force loading.
Middle ear reflectance in various middle disease states.
Authors: Bance Manohar , Garland Phillip , Robert Adamson , Jeremy Brown
Published: October 2010

Many middle ear conditions are difficult to diagnose based on inspection of the eardrum, tympanometry, and audiometry. Most appear as a simple conductive hearing loss. We report findings using wideband middle ear reflectance measurements in a range of middle ear and inner ear conditions, particularly looking for evidence of middle ear involvement in some traditionally inner ear conditions such as Meniere’s disease.
Transformation acoustics.
Authors: Cummer Steven A.
Published: October 2010

It is now well understood how coordinate transformations of the Maxwell equations can be interpreted in terms of an electromagnetic material in the original coordinates with transformed values of permittivity and permeability. Through this transformation optics approach, the bending and stretching of electromagnetic fields specified by coordinate transformations can be implemented with electromagnetic materials, enabling unexpected and interesting solutions such as electromagnetic cloaking. In this presentation we describe work by us and others that show how this same concept can be extended to realize arbitrary manipulations of acoustic waves, including cloaking, using materials with very specific properties. While the concept of transformation acoustics was first demonstrated by analogy with electromagnetics, here we derive it from first principles through an analysis of the divergence and gradient operators under coordinate transformations. We will also discuss several approaches for engineering composite materials with the acoustic properties needed to realize transformation acoustics devices and demonstrate their performance through full wave simulations.
Active acoustic metamaterials.
Authors: Baz Amr
Published: October 2010

Extensive efforts are being exerted to develop various types of acoustic metamaterials to effectively control the flow of acoustical energy through these materials. However, all these efforts are focused on passive metamaterials with fixed material properties. The emphasis is placed here on the development of a class of acoustic metamaterials with tunable effective densities and bulk modulus in an attempt to enable the control of wave propagation. More importantly, the active metamaterials can be tailored to have increasing or decreasing variation of the material properties along and across the material volume. With such unique capabilities, physically realizable acoustic cloaks can be achieved and objects treated with these active metamaterials can become acoustically invisible. The theoretical analysis of this class of active acoustic metamaterials will be presented and the theoretical predictions are determined for an array of fluid cavities separated by piezoelectric boundaries. These boundaries control the stiffness of the individual cavity and in turn its dynamical density and bulk modulus. Various configurations will be considered to achieve different spectral and spatial control of the density and bulk modulus of this class of acoustic metamaterials. Extensive efforts are now exerted to build and test modules of these active acoustic metamaterials in order to build practical configurations of acoustic cloaks.