bluuebunny/crossref_metadata_2025 huggingface dataset:
Passive Samplers for Monitoring VOCs in Groundwater and the Prospects Related to Mass Flux Measurements
Authors: Verreydt Goedele , Bronders Jan , Van Keer Ilse , Diels Ludo , Vanderauwera Paul
Published: May 2010

Measurement and interpretation of mass fluxes in favor of concentrations is gaining more and more interest, especially within the framework of the characterization and management of large‐scale volatile organic carbon (VOC) groundwater contamination (source zones and plumes). Traditional methods of estimating contaminant fluxes and discharges involve individual measurements/calculations of the Darcy water flux and the contaminant concentrations. However, taken into account the spatially and temporally varying hydrologic conditions in complex, heterogeneous aquifers, higher uncertainty arises from such indirect estimation of contaminant fluxes. Therefore, the potential use of passive sampling devices for the direct measurement of groundwater‐related VOC mass fluxes is examined. A review of current passive samplers for the measurement of organic contaminants in water yielded the selection of 18 samplers that were screened for a number of criteria. These criteria are related to the possible application of the sampler for the measurement of VOC mass fluxes in groundwater. This screening study indicates that direct measurement of VOC mass fluxes in groundwater is possible with very few passive samplers. Currently, the passive flux meter (PFM) is the only passive sampler which has proven to effectively measure mass fluxes in near source groundwater. A passive sampler for mass flux measurement in plume zones with regard to long‐term monitoring (several months to a year) still needs to be developed or optimized. A passive sampler for long‐term monitoring of contaminant mass fluxes in groundwater would be of considerable value in the development of risk‐based assessment and management of soil and groundwater pollutions.
Groundwater Monitoring on Guam: Management Responses to Recent Water Quality Violations
Authors: Denton Gary R.W. , Sian‐Denton Carmen M.
Published: May 2010

Guam has one of the finest limestone aquifers in the world. Located in the northern half of the island, this vital underground resource supplies the local community with about 80% of its drinking water needs. The majority of the island’s approximately 180,000 inhabitants live in the northern half of the island where significant economic growth and urban development have occurred over the last 30 years. The U.S. military has also occupied large tracts of land in this region for the past 60 years. The risks of groundwater contamination are, therefore, very real considering the population density in northern Guam and the rapid recharge rates to the underlying aquifer. Since April 1996, Guam Waterworks Authority (GWA) has regularly monitored the island’s drinking water resources for chemical and biological contaminants in accordance with the U.S. Safe Drinking Water Act requirements. This report summarizes and compares the groundwater data sets for two discrete time intervals: 1996 through 2001 and 2002 through 2007 for chemicals, and 1997(8) through 2002 and 2003 through 2007 for bacteria. Adaptive management strategies that evolved to deal with contaminant violations over this time frame are critically discussed. Overall, 95% of all GWA’s drinking water production wells were considered to be in relatively good shape from a chemical standpoint. Identified chemicals of concern were chlordane, ethylene dibromide, perchloroethylene, trichloroethylene, and nitrate. The microbiological integrity of Guam’s groundwater was, by comparison, less impressive prior to 2003 because of numerous wastewater spills, leaks, and overflows. Improved management practices introduced shortly afterward have significantly reduced the incidence of Escherichia coli contamination in recent years.
Characterizing urbanization, and agricultural and conservation land‐use change in Riverside County, California, USA
Authors: Chen Xiongwen , Li Bai‐Lian , Allen Michael F.
Published: May 2010

Monitoring trends in urbanization and land use related to population growth and changing social and economic conditions is an important tool for developing in land use and habitat conservation policy. We analyzed urbanization and agricultural land‐use change in Riverside County, California from 1984 to 2002, comparing maps every two years on the basis of aerial photographs. Matrix analysis combined with information theory was applied to study land type conversion. Results showed that the total area of “Urban and Built‐Up Land” increased the most whereas total area of “Prime Farmland” decreased most. Land‐use characterized as “Grazing Land,”“Farmland of Local Importance,” and “Farmland of Statewide Importance” also decreased. Mean patch size also decreased for “Grazing Land,”“Water Area,”“Other Land,” and “Prime Farmland.” The diversity of land types decreased dramatically after 1992. Urbanization patterns were different among three city groups (Riverside City, Coachella Valley, and Blythe), indicating the different times for “leapfrog” development in the three areas. Furthermore, the unpredictability and change in composition of land use increased after 1996 due to intensified urbanization. If the current driving forces continue, our model projects that in 2020 the area of “Urban and Built‐Up Land” may increase between 25% and 39% in comparison with 2002. Percentages of most agricultural land types are projected to decrease, especially “Farmland of Local Importance,”“Prime Farmland,” and “Farmland of Statewide Importance.” If the county's goal is to preserve agricultural lands and natural biodiversity, while maintaining sustainable development, current land‐use policies and practices should be changed. This study demonstrates new useful methods for monitoring and detection of change of land‐use processes.
Expression of the inulinase gene from the marine‐derived Pichia guilliermondii in Saccharomyces sp. W0 and ethanol production from inulin
Authors: Zhang Tong , Chi Zhe , Chi Zhenming , Parrou Jean‐Luc , Gong Fang
Published: May 2010

It has been confirmed that Saccharomyces sp. W0 can produce high concentration of ethanol. In this study, the INU1 gene cloned from the marine‐derived Pichia guilliermondii was transformed into uracil mutant of Saccharomyces sp. W0. The positive transformant Inu‐66 obtained could produce 34.2 U ml−1 of extracellular inulinase within 72 h of cultivation. It was found that 15.2 U of inulinase activity per one gram of inulin was suitable for inulin hydrolysis and ethanol production by the transformant Inu‐66. During the small‐scale fermentation, 13.7 ml of ethanol in 100 ml of medium was produced and 99.1% of the added inulin was utilized by the transformant. During the 2 l fermentation, 14.9% (v/v) of ethanol was produced from inulin and 99.5% of the added inulin was converted into ethanol, CO2 and cell mass.
Microbial diagnostic microarray for food‐ and water‐borne pathogens
Authors: Kostić Tanja , Stessl Beatrix , Wagner Martin , Sessitsch Angela , Bodrossy Levente
Published: May 2010

A microbial diagnostic microarray for the detection of the most relevant bacterial food‐ and water‐borne pathogens and indicator organisms was developed and thoroughly validated. The microarray platform based on sequence‐specific end labelling of oligonucleotides and the pyhylogenetically robust gyrB marker gene allowed a highly specific (resolution on genus/species level) and sensitive (0.1% relative and 104 cfu absolute detection sensitivity) detection of the target pathogens. Validation was performed using a set of reference strains and a set of spiked environmental samples. Reliability of the obtained data was additionally verified by independent analysis of the samples via fluorescence in situ hybridization (FISH) and conventional microbiological reference methods. The applicability of this diagnostic system for food analysis was demonstrated through extensive validation using artificially and naturally contaminated spiked food samples. The microarray‐based pathogen detection was compared with the corresponding microbiological reference methods (performed according to the ISO norm). Microarray results revealed high consistency with the reference microbiological data.
Monte Carlo integration over stepping stone models for spatial genetic inference using approximate Bayesian computation
Authors: BAIRD STUART J. E. , SANTOS FILIPE
Published: May 2010

Approximate Bayesian computation (ABC) substitutes simulation for analytic models in Bayesian inference. Simulating evolutionary scenarios under Kimura’s stepping stone model (KSS) might therefore allow inference over spatial genetic process where analytical results are difficult to obtain. ABC first creates a reference set of simulations and would proceed by comparing summary statistics over KSS simulations to summary statistics from localities sampled in the field, but: comparison of which localities and stepping stones? Identical stepping stones can be arranged so two localities fall in the same stepping stone, nearest or diagonal neighbours, or without contact. None is intrinsically correct, yet some choice must be made and this affects inference. We explore a Bayesian strategy for mapping field observations onto discrete stepping stones. We make Sundial, for projecting field data onto the plane, available. We generalize KSS over regular tilings of the plane. We show Bayesian averaging over the mapping between a continuous field area and discrete stepping stones improves the fit between KSS and isolation by distance expectations. We make Tiler Durden available for carrying out this Bayesian averaging. We describe a novel parameterization of KSS based on Wright’s neighbourhood size, placing an upper bound on the geographic area represented by a stepping stone and make it available as m Vector. We generalize spatial coalescence recursions to continuous and discrete space cases and use these to numerically solve for KSS coalescence previously examined only using simulation. We thus provide applied and analytical resources for comparison of stepping stone simulations with field observations.
Effect of hot desert weathering on the bulk‐rock iron isotope composition of  L6 and H5 ordinary chondrites
Authors: SAUNIER Gaëlle , POITRASSON Franck , MOINE Bertrand , GREGOIRE Michel , SEDDIKI Abdelmadjid
Published: May 2010

Abstract– Although iron isotopes are increasingly used for meteorites studies, no attempt has been made to evaluate the effect of terrestrial weathering on this isotopic tracer. We have thus conducted a petrographic, chemical, and iron isotopic study of equilibrated ordinary chondrites (OC) recovered from hot Moroccan and Algerian Saharan deserts environment. As previously noticed, we observe that terrestrial desertic weathering is characterized by the oxidation of Fe‐Ni metal (Fe0), sulfide and Fe2+ occurring in olivine and pyroxene. It produces Fe‐oxides and oxyhydroxides that partially replace metal, sulfide grains and also fill fractures. The bulk chemical compositions of the ordinary chondrites studied show a strong Sr and Ba enrichment and a S depletion during weathering. Bulk meteoritic iron isotope compositions are well correlated with the degree of weathering and S, Sr, and Ba contents. Most weathered chondrites display the heaviest isotopic composition, by up to 0.1‰, which is of similar magnitude to the isotopic variations resulting from meteorite parent bodies’ formation and evolution. This is probably due to the release of isotopically light Fe2+ to waters on the Earth’s surface. Hence, when subtle Fe isotopic effects have to be studied in chondrites, meteorites with weathering grade above W2 should be avoided.
Multiharmonic Response Analysis of Systems With Local Nonlinearities Based on Describing Functions and Linear Receptance
Authors: Wei F. , Zheng G. T.
Published: May 2010

Direct time integration methods are usually applied to determine the dynamic response of systems with local nonlinearities. Nevertheless, these methods are computationally expensive to predict the steady state response. To significantly reduce the computational effort, a new approach is proposed for the multiharmonic response analysis of dynamical systems with local nonlinearities. The approach is based on the describing function (DF) method and linear receptance data. With the DF method, the kinetic equations are converted into a set of complex algebraic equations. By using the linear receptance data, the dimension of the complex algebraic equations, which should be solved iteratively, are only related to nonlinear degrees of freedom (DOFs). A cantilever beam with a local nonlinear element is presented to show the procedure and performance of the proposed approach. The approach can greatly reduce the size and computational cost of the problem. Thus, it can be applicable to large-scale systems with local nonlinearities.
Sound Transmission Characteristics of Asymmetric Sandwich Panels
Authors: Zhou Ran , Crocker Malcolm J.
Published: May 2010

Governing equations for the forced vibration of asymmetric sandwich panels are developed from energy relationships. A wave impedance analysis model for the sound transmission loss of asymmetric sandwich panels is presented. The wave impedance analysis model is compared with other wave impedance analysis models for sandwich panels. Comparisons between predictions of the sound transmission loss of two sandwich panels obtained from two wave impedance analysis models for asymmetric sandwich panels are given.
Influence of Multiphysical Effects on the Dynamics of High Speed Minirotors—Part I: Theory
Authors: Dikmen Emre , van der Hoogt Peter J. M. , de Boer André , Aarts Ronald G. K. M.
Published: May 2010

In this study, a modeling approach has been developed to take multiphysical effects into account in the prediction of the rotordynamic behavior of high speed minirotating machinery with a moderate flow confinement. The temperature increase in the confinement and the flow induced forces resulting from the surrounding fluid have been studied and these models are combined with the structural finite element models for determining the rotordynamic behavior. The structure has been analyzed via finite elements based on Timoshenko beam theory. Flow induced forces are implemented to the structure as added mass-stiffness-damping at each node representing the structure in the fluid confinement. A thermal model based on thermal networks in steady-state has been developed. This model is used to calculate the heat dissipation resulting from air friction and temperature increase in the air gap as a function of rotation speed. At each rotation speed, the temperature in the air gap between the rotor and stationary casing is calculated and air properties, which are used for the calculation of flow induced forces are updated. In this way, thermal and fluid effects in medium gap confinements are coupled with the rotordynamic model and their effects on stability, critical speeds, and vibration response are investigated. The experimental results are reported and compared with the theoretical results in an accompanying paper (Part II).
Effect of the Denoising on Acoustic Emission Signals
Authors: Chiementin X. , Mba D. , Charnley B. , Lignon S. , Dron J. P.
Published: May 2010

The acoustic emission (AE) technology is growing in its applicability to bearing defect diagnosis. Several publications have shown its effectiveness for earlier detection of bearing defects than vibration analysis. In the latter instance, detection and monitoring of defects can be achieved through temporal statistical indicators, which can further be improved by application of denoising techniques. This paper investigates the application of temporal statistical indicators for AE detection of bearing defects on a purposely built test-rig and assesses the effectiveness of various denoising techniques in improving sensitivity to early defect detection. It is concluded that the denoising methods offer significant improvements in identifying defects with AE, especially the self-adaptive noise cancellation method.
Noncontact scanning nonlinear dielectric microscopy imaging of TiO2(110) surfaces
Authors: Kin Nobuhiro , Cho Yasuo
Published: May 2010

The authors simultaneously observed the typical topography and local electric dipole moment distribution of Ti atoms on a TiO2(110) 1×1 structure using noncontact scanning nonlinear dielectric microscopy (NC-SNDM). The upward polarization observed in polarization distribution images implies that the topography determined from the higher-order nonlinear dielectric constant signals is that of Ti4+. They also have examined the difference between the images formed by NC-SNDM and scanning tunneling microscopy. To acquire atomic resolution images using NC-SNDM, it was found that higher annealing temperatures were required.
A computer controlled pendulum with position readout
Authors: Hauptfleisch H. , Gasenzer T. , Meier K. , Nachtmann O. , Schemmel J.
Published: May 2010

We have designed and constructed a physical pendulum that allows us to demonstrate its behavior for a variety of forces and initial conditions. All parameters in the equation of motion can be defined by the user. The apparatus can demonstrate phenomena ranging from simple undamped harmonic oscillations to chaotic behavior. The position of the pendulum and the derived quantities such as the velocity and acceleration can be stored for later analysis.
The influence of the Yarkovsky effect on the global temperature
Authors: De Vos Alexis , Kaplar Anna
Published: May 2010

We present an analytic model for the diurnal Yarkovsky effect. This effect is the rebound force, felt by a celestial body, because of its own nonisotropic emission of infrared radiation. As an illustration, we investigate how the Yarkovsky effect influences the energy balance of a celestial body and thus its average surface temperature.
Basketballs as spherical acoustic cavities
Authors: Russell Daniel A.
Published: May 2010

The sound field resulting from striking a basketball is found to be rich in frequency content, with over 50 partials in the frequency range of 0–12 kHz. The frequencies are found to closely match theoretical expectations for standing wave patterns inside a spherical cavity. Because of the degenerate nature of the mode shapes, explicit identification of the modes is not possible without internal investigation with a microphone probe. A basketball proves to be an interesting application of a boundary value problem involving spherical coordinates.
Application of DVD/CD pickup optics to microscopy and fringe projection
Authors: Ferrari José A. , Frins Erna , Ayubi Gastón , Gentilini Juan , Perciante César D.
Published: May 2010

We discuss a low-cost microscope that is constructed using commercial DVD and CD pickups and demonstrate its fine focus capacity and high resolution. Also, we demonstrate a fringe projection interferometer that uses the three-beam positioning system of a CD reader. We show that with a simple rotation of the grating placed inside the pickup head, an electrically controlled fringe-shift system is obtained, which can be used for 3D profilometry. Despite the low cost of these systems, they have a performance comparable to more complex systems.
On random search: Collection kinetics of Paramecia into a trap embedded in a closed domain
Authors: Deforet Maxime , Duplat Jérôme , Vandenberghe Nicolas , Villermaux Emmanuel
Published: May 2010

We study the kinetics of a large number of organisms initially spread uniformly in a circular two-dimensional medium, at the center of which a smaller circular trap has been introduced. We take advantage of the acidophily of Paramecium caudatum, which, coming from a neutral medium, penetrates a region of moderate acidity but moves back in the opposite situation when it meets a sharp negative acidity gradient to quantify its rate of irreversible aggregation into a spot of acidified medium in water. Two regimes are distinguished: A ballistic regime characteristic of “fresh” paramecia where the organisms swim in a straight path with a well defined velocity and a Brownian regime characteristic of older paramecia where the mean free path of the organisms is smaller than the system size. Both regimes are characterized by distinct aggregation laws. They both result from a pure random trapping process that appears to have no adaptive strategy.
Reflection above the barrier as tunneling in momentum space
Authors: Jaffe R. L.
Published: May 2010

Quantum mechanics predicts an exponentially small probability that a particle with energy greater than the height of a potential barrier will reflect from the barrier in violation of classical expectations. This process can be regarded as tunneling in momentum space, leading to a simple derivation of the reflection probability.
Electric fields in the presence of conducting objects
Authors: Marrero José Luis Rodríguez
Published: May 2010

When a conducting object is placed in a region where there is an electric field, charges are induced on its surface. We seek the unique surface charge density that produces an electric field that cancels the original field inside the conductor. When the external sources are point charges or uniform fields, it is easy to determine the field that the induced charges must produce inside the conducting object. Up to a constant, this field gives the potential on the conducting surface, which suffices to determine the potential function outside the conductor. The perturbing field produced by the induced charges is obtained from this potential, and a simple boundary condition gives us the induced surface charge density.
Measurements of the speed of light in water using Foucault’s technique
Authors: Brody Jed , Griffin Laura , Segre Phil
Published: May 2010

We describe how to modify an existing speed-of-light apparatus to measure the speed of light in water. We derive the necessary formulas to account for refraction and light’s passage through both water and air. We obtain (3.00±0.09)×108 m/s for the speed of light in air and (2.1±0.1)×108 m/s for the speed of the light in water. Both results are within 7% of established values.
Mode filters and energy conservation
Authors: Udovydchenkov Ilya A. , Rypina Irina I. , Brown Michael G.
Published: May 2010

The discrete form of the mode filtering problem is considered. The relevant equations constitute a linear inverse problem. Solutions to problems of this type are subject to a well-known trade-off between resolution and precision. But unlike the typical linear inverse problem, the correctly formulated mode filtering problem is subject to an energy conservation constraint. This letter focuses on the importance of satisfying, approximately at least, the energy conservation constraint when mode filtering is performed.
Design and acoustic characterization of limited diffraction ultrasonic devices
Authors: Aulet A. , Núñez I. , Moreno E. , Eiras J. A. , Negreira C. A.
Published: May 2010

Limited diffraction ultrasonic transducers are devices that have a large depth of acoustic field without important effects of diffraction, which make them optimal in applications of medical images, among others. This report details how this special type of piezoelectric device was designed by means of a simple technology using three electrodes in the form of concentric rings in both faces of a ferroelectric ceramic disk, which were used to apply a profile of non-homogeneous polarization. Once designed, the radiation fields emitted by these resonators were characterized experimentally by electro-acoustic and acousto-optic techniques and were compared with those emitted by conventional devices. As shown in the experimental characterizations, ultrasonic transducers with optimal properties for use in medical applications such as good collimation of the ultrasound beam, high lateral resolution, as well as little effects of diffraction were obtained.
Total absorption peak by use of a rigid frame porous layer backed by a rigid multi-irregularities grating
Authors: Groby J.-P. , Lauriks W. , Vigran T. E.
Published: May 2010

The acoustic properties of a low resistivity porous layer backed by a rigid plate containing periodic rectangular irregularities, creating a multicomponent diffraction gratings, are investigated. Numerical and experimental results show that the structure possesses a total absorption peak at the frequency of the modified mode of the layer, when designed as proposed in the article. These results are explained by an analysis of the acoustic response of the whole structure and especially by the modal analysis of the configuration. When more than one irregularity per spatial period is considered, additional higher frequency peaks are observed.
Vocal fold and ventricular fold vibration in period-doubling phonation: Physiological description and aerodynamic modeling
Authors: Bailly Lucie , Henrich Nathalie , Pelorson Xavier
Published: May 2010

Occurrences of period-doubling are found in human phonation, in particular for pathological and some singing phonations such as Sardinian A Tenore Bassu vocal performance. The combined vibration of the vocal folds and the ventricular folds has been observed during the production of such low pitch bass-type sound. The present study aims to characterize the physiological correlates of this acoustical production and to provide a better understanding of the physical interaction between ventricular fold vibration and vocal fold self-sustained oscillation. The vibratory properties of the vocal folds and the ventricular folds during phonation produced by a professional singer are analyzed by means of acoustical and electroglottographic signals and by synchronized glottal images obtained by high-speed cinematography. The periodic variation in glottal cycle duration and the effect of ventricular fold closing on glottal closing time are demonstrated. Using the detected glottal and ventricular areas, the aerodynamic behavior of the laryngeal system is simulated using a simplified physical modeling previously validated in vitro using a larynx replica. An estimate of the ventricular aperture extracted from the in vivo data allows a theoretical prediction of the glottal aperture. The in vivo measurements of the glottal aperture are then compared to the simulated estimations.
Stimulus uncertainty and insensitivity to pitch-change direction
Authors: Mathias Samuel R. , Micheyl Christophe , Bailey Peter J.
Published: May 2010

In a series of experiments, Semal and Demany [(2006). J. Acoust. Soc. Am. 120, 3907–3915] demonstrated that some normally hearing listeners are unable to determine the direction of small but detectable differences in frequency between pure tones. Unlike studies demonstrating similar effects in patients with brain damage, the authors used stimuli in which the standard frequency of the tones was highly uncertain (roved) over trials. In Experiment 1, listeners were identified as insensitive to the direction of pitch changes using stimuli with frequency roving. When listeners were retested using stimuli without roving in Experiment 2, impairments in pitch-direction identification were generally much less profound. In Experiment 3, frequency-roving range had a systematic effect on listeners’ thresholds, and impairments in pitch-direction identification tended to occur only when the roving range was widest. In Experiment 4, the influence of frequency roving was similar for continuous frequency changes as for discrete changes. Possible explanations for the influence of roving on listeners’ insensitivity to pitch-change direction are discussed.
A statistical approach to direct density of states measurements in disordered systems
Authors: Hildebrand W. K. , Cobus L. A. , Page J. H.
Published: May 2010

A statistical method for measuring the modal density of elastic waves through direct mode counting in strongly scattering disordered systems is presented. To illustrate this approach, the results of ultrasonic experiments in a highly porous sintered glass bead network are reported. This method is shown to yield a reliable and robust measurement of the density of states, enabling mode-counting techniques to be applied to increasingly complex systems, where modal overlap and sensitivity to experimental conditions have previously hampered definitive results.
Time and frequency parameters of bottlenose dolphin whistles as predictors of surface behavior in the Mississippi Sound
Authors: Hernandez Erica N. , Solangi Moby , Kuczaj Stan A.
Published: May 2010

Acoustic characteristics related to contour of the whistle (such as highest and lowest frequency, beginning and ending frequency, whistle duration, and number of turns) of bottlenose dolphin (Tursiops truncatus) whistles were measured to test whether any of the measurements were related to the behavioral state of the dolphins when the whistle was recorded (coded as mill, travel, mill/travel, feed, or social). Objective measures of time and frequency were obtained using Raven, while number of turns in a whistle was determined by human raters. In all a series of discriminant function analyses using the acoustic characteristics to predict the behavioral state, the highest standardized canonical discriminant function coefficients were: lowest frequency, number of turns, and duration. The models that incorporated these variables performed significantly better than chance at correctly assigning the whistles into the surface behavior category in which they were recorded. The rate of whistling was related to group size, surface behavior and season via a series of two-way ANOVAs (analysis of variance).
A virtual trajectory model predicts differences in vocal fold kinematics in individuals with vocal hyperfunction
Authors: Stepp Cara E. , Hillman Robert E. , Heaton James T.
Published: May 2010

A simple, one degree of freedom virtual trajectory model of vocal fold kinematics was developed to investigate whether kinematic features of vocal fold movement confirm increased muscle stiffness. Model simulations verified that increases in stiffness were associated with changes in kinematic parameters, suggesting that increases in gesture rate would affect kinematic features to a lesser degree in vocal hyperfunction patients given the increased levels of muscle tension they typically employ to phonate. This hypothesis was tested experimentally in individuals with muscle tension dysphonia (MTD; N=10) and vocal nodules (N=10) relative to controls with healthy normal voice (N=10) who were examined with trans-nasal endoscopy during a simple vocal fold abductory-adductory task. Kinematic measures in MTD patients were less affected by increased gesture rate, consistent with the hypothesis that these individuals have elevated typical laryngeal muscle tension. Group comparisons of the difference between medium and fast gesture rates (Mann–Whitney, one-tailed) showed statistically significant differences between the control and MTD individuals on the two kinematic features examined (p<0.05). Results in nodules participants were mixed and are discussed independently. The findings support the potential use of vocal fold kinematics as an objective clinical assay of vocal hyperfunction.
A description of sounds recorded from melon-headed whales (Peponocephala electra) off Hawai‘i
Authors: Frankel Adam S. , Yin Suzanne
Published: May 2010

Between 2004 and 2006, large groups of melon-headed whales were recorded off the Big Island of Hawai‘i. No other odontocete species were sighted in these groups. Recordings contained echolocation clicks, burst-pulse sounds, and whistles. Echolocation clicks typically contained energy beginning at 13 kHz and continued strongly to the frequency cutoff of the recording system, suggesting that the frequency content of the clicks continued well beyond 24 kHz. Burst-pulse sounds were typically short, with a mean duration of 586 ms with a mean inter-pulse interval of 2.47 ms. The distribution of numbers of pulses was skewed toward fewer pulses, with a mean of 46.7 pulses. Overall, whistles were relatively simple frequency-modulated downsweeps, upsweeps, and sinusoidal signals. Fundamental frequencies ranged from 890 Hz to 23.5 kHz. Most whistles had smooth contours, although frequency steps were observed. Whistles were generally short, with a mean duration of 586 ms. The acoustic characteristics of these whistles were similar to those in the only previously published descriptions of melon-headed whale vocalizations [Watkins et al. (1997). Caribbean J. Sci. 33, 34–40; Janik and Curran (2007). 17th Biennial Conference on the Biology of Marine Mammals, Capetown, South Africa] and were shown to be distinguishable from whistles of other odontocete species.
Sound source localization by the plainfin midshipman fish, Porichthys notatus
Authors: Zeddies David G. , Fay Richard R. , Alderks Peter W. , Shaub Kiel S. , Sisneros Joseph A.
Published: May 2010

The aim of this study was to use plainfin midshipman fish (Porichthys notatus) as a general model to explore how fishes localize an underwater sound source in the relatively simple geometry of a monopole sound field. The robust phonotaxic responses displayed by gravid females toward a monopole sound projector (J-9) broadcasting a low-frequency (90 Hz) tone similar to the fundamental frequency of the male’s advertisement call were examined. The projector’s sound field was mapped at 5 cm resolution azimuth using an eight-hydrophone array. Acoustic pressure was measured with the array and acoustic particle motion was calculated from pressure gradients between hydrophones. The response pathways of the fish were analyzed from video recordings and compared to the sound field. Gravid females at initial release were directed toward the sound source, and the majority (73%) swam to the playback projector with straight to slightly curved tracks in the direction of the source and in line with local particle motion vectors. In contrast, the initial direction of the control (sound-off) group did not differ from random. This paper reports on a comparison of fish localization behavior with directional cues available in the form of local particle motion vectors.
Adaptive environment classification system for hearing aids
Authors: Lamarche Luc , Giguère Christian , Gueaieb Wail , Aboulnasr Tyseer , Othman Hisham
Published: May 2010

An adaptive sound classification framework is proposed for hearing aid applications. The long-term goal is to develop fully trainable instruments in which both the acoustical environments encountered in daily life and the hearing aid settings preferred by the user in each environmental class could be learned. Two adaptive classifiers are described, one based on minimum distance clustering and one on Bayesian classification. Through unsupervised learning, the adaptive systems allow classes to split or merge based on changes in the ongoing acoustical environments. Performance was evaluated using real-world sounds from a wide range of acoustical environments. The systems were first initialized using two classes, Speech and Noise, followed by a testing period when a third class, Music, was introduced. Both systems were successful in detecting the presence of an additional class and estimating its underlying parameters, reaching a testing accuracy close to the target rates obtained from best-case scenarios derived from non-adaptive supervised versions of the classifiers (about 3% lower performance). The adaptive Bayesian classifier resulted in a 4% higher overall accuracy upon splitting adaptation than the minimum distance classifier. Merging accuracy was found to be the same in the two systems and within 1%–2% of the best-case supervised versions.
Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II
Authors: Bæk David , Jensen Jørgen Arendt , Willatzen Morten
Published: May 2010

FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks as well as pressure and intensity measurements in front of a 128 element commercial convex medical transducer are compared to the simulations. Results show that the models can predict the pressure from the piezoceramic disks with a root mean square (rms) error of 11.2% to 36.2% with a 2 dB amplitude decrease. The current through the external driving circuits are predicted within 8.6% to 36% rms error. Prediction errors of 30% and in the range of 5.8%–19.9% for the pressure and the intensity, respectively, are found when simulating the commercial transducer. It is concluded that the multilayer transducer model and the FIELD II software in combination give good agreement with measurements.
Integration of auditory and vibrotactile stimuli: Effects of frequency
Authors: Wilson E. Courtenay , Reed Charlotte M. , Braida Louis D.
Published: May 2010

Perceptual integration of vibrotactile and auditory sinusoidal tone pulses was studied in detection experiments as a function of stimulation frequency. Vibrotactile stimuli were delivered through a single channel vibrator to the left middle fingertip. Auditory stimuli were presented diotically through headphones in a background of 50 dB sound pressure level broadband noise. Detection performance for combined auditory-tactile presentations was measured using stimulus levels that yielded 63% to 77% correct unimodal performance. In Experiment 1, the vibrotactile stimulus was 250 Hz and the auditory stimulus varied between 125 and 2000 Hz. In Experiment 2, the auditory stimulus was 250 Hz and the tactile stimulus varied between 50 and 400 Hz. In Experiment 3, the auditory and tactile stimuli were always equal in frequency and ranged from 50 to 400 Hz. The highest rates of detection for the combined-modality stimulus were obtained when stimulating frequencies in the two modalities were equal or closely spaced (and within the Pacinian range). Combined-modality detection for closely spaced frequencies was generally consistent with an algebraic sum model of perceptual integration; wider-frequency spacings were generally better fit by a Pythagorean sum model. Thus, perceptual integration of auditory and tactile stimuli at near-threshold levels appears to depend both on absolute frequency and relative frequency of stimulation within each modality.
Coherent backscattering effect from mid-frequency shallow water reverberation
Authors: Sabra Karim G.
Published: May 2010

The coherent backscattering (or backscattering enhancement) effect results from persistent interferences between multiply scattered waves propagating along reciprocal paths. This effect results in a doubling of the recorded backscattered intensity reflected exactly in the backward direction with respect to any other direction, after averaging intensity measurements collected over multiple emission angles. This letter presents experimental observations of the coherent backscattering effect from mid-frequency (3–4 kHz) shallow water reverberation measurements collected using a two-dimensional hydrophone array (8.4×1.5 m2). These results demonstrate the presence of coherent effects in shallow water reverberation not commonly accounted for.
Acoustic scattering by arbitrary distributions of disjoint, homogeneous cylinders or spheres
Authors: Hesford Andrew J. , Astheimer Jeffrey P. , Waag Robert C.
Published: May 2010

A T-matrix formulation is presented to compute acoustic scattering from arbitrary, disjoint distributions of cylinders or spheres, each with arbitrary, uniform acoustic properties. The generalized approach exploits the similarities in these scattering problems to present a single system of equations that is easily specialized to cylindrical or spherical scatterers. By employing field expansions based on orthogonal harmonic functions, continuity of pressure and normal particle velocity are directly enforced at each scatterer using diagonal, analytic expressions to eliminate the need for integral equations. The effect of a cylinder or sphere that encloses all other scatterers is simulated with an outer iterative procedure that decouples the inner-object solution from the effect of the enclosing object to improve computational efficiency when interactions among the interior objects are significant. Numerical results establish the validity and efficiency of the outer iteration procedure for nested objects. Two- and three-dimensional methods that employ this outer iteration are used to measure and characterize the accuracy of two-dimensional approximations to three-dimensional scattering of elevation-focused beams.
Influences of multiple memory systems on auditory mental image acuity
Authors: Navarro Cebrian Ana , Janata Petr
Published: May 2010

The influence of different memory systems and associated attentional processes on the acuity of auditory images, formed for the purpose of making intonation judgments, was examined across three experiments using three different task types (cued-attention, imagery, and two-tone discrimination). In experiment 1 the influence of implicit long-term memory for musical scale structure was manipulated by varying the scale degree (leading tone versus tonic) of the probe note about which a judgment had to be made. In experiments 2 and 3 the ability of short-term absolute pitch knowledge to develop was manipulated by presenting blocks of trials in the same key or in seven different keys. The acuity of auditory images depended on all of these manipulations. Within individual listeners, thresholds in the two-tone discrimination and cued-attention conditions were closely related. In many listeners, cued-attention thresholds were similar to thresholds in the imagery condition, and depended on the amount of training individual listeners had in playing a musical instrument. The results indicate that mental images formed at a sensory/cognitive interface for the purpose of making perceptual decisions are highly malleable.
Phase effects on the perceived elevation of complex tones
Authors: Hartmann William M. , Best Virginia , Leung Johahn , Carlile Simon
Published: May 2010

Free-field source localization experiments with 30 source locations, symmetrically distributed in azimuth, elevation, and front-back location, were performed with periodic tones having different phase relationships among their components. Although the amplitude spectra were the same for these different kinds of stimuli, the tones with certain phase relationships were successfully localized while the tones with other phases led to large elevation errors and front-back reversals, normally growing with stimulus level. The results show that it is not enough to have a smooth, broadband, long-term signal spectrum for successful sagittal-plane localization. Instead, temporal factors are important. A model calculation investigates the idea that the tonotopic details that mediate localization need to be simultaneously, or almost simultaneously, accessible in the auditory system in order to achieve normal elevation perception. A qualitative model based on lateral inhibition seems capable in principle of accounting for both the phase effects and level effects.
Click- and chirp-evoked human compound action potentials
Authors: Chertoff Mark , Lichtenhan Jeffery , Willis Marie
Published: May 2010

In the experiments reported here, the amplitude and the latency of human compound action potentials (CAPs) evoked from a chirp stimulus are compared to those evoked from a traditional click stimulus. The chirp stimulus was created with a frequency sweep to compensate for basilar membrane traveling wave delay using the O-Chirp equations from Fobel and Dau [(2004). J. Acoust. Soc. Am. 116, 2213–2222] derived from otoacoustic emission data. Human cochlear traveling wave delay estimates were obtained from derived compound band action potentials provided by Eggermont [(1979). J. Acoust. Soc. Am. 65, 463–470]. CAPs were recorded from an electrode placed on the tympanic membrane (TM), and the acoustic signals were monitored with a probe tube microphone attached to the TM electrode. Results showed that the amplitude and latency of chirp-evoked N1 of the CAP differed from click-evoked CAPs in several regards. For the chirp-evoked CAP, the N1 amplitude was significantly larger than the click-evoked N1s. The latency-intensity function was significantly shallower for chirp-evoked CAPs as compared to click-evoked CAPs. This suggests that auditory nerve fibers respond with more unison to a chirp stimulus than to a click stimulus.
Measurement of wind noise levels in streamlined probes
Authors: Webster Jeremy , Raspet Richard , Yu Jiao , Prather Wayne E.
Published: May 2010

This paper investigates the wind noise pressure spectra measured by aerodynamically designed devices in turbulent flow. Such measurement probes are often used in acoustic measurements in wind tunnels to reduce the pressure fluctuations generated by the interaction of the devices with the incident flow. When placed in an outdoor turbulent environment however, their performance declines noticeably. It is hypothesized that these devices are measuring the stagnation pressures generated by the cross flow components of the turbulence. Predictions for the cross flow contribution to the stagnation pressure spectra based on measured velocity spectra are developed, and are then compared to the measured pressure spectra in four different probe type devices in windy conditions outdoors. The predictions agree well with the measurements and show that the cross flow contamination coefficient is on the order of 0.5 in outdoor turbulent flows in contrast to the published value of 0.15 for measurements in a turbulent jet indoors.
Design optimization of wide-band Tonpilz piezoelectric transducer with a bending piezoelectric disk on the radiation surface
Authors: Saijyou Kenji , Okuyama Tomonao
Published: May 2010

Wide-band Tonpilz piezoelectric transducer with a bending piezoelectric disk on the radiation surface has been proposed to improve sonar detection performance in shallow water. This transducer is driven by utilizing two vibration modes, i.e., longitudinal and bending. Consequently, to achieve a wide-band signal transmission by this transducer, the phase difference between signals, which drive the ring-stack and the bending-disk piezoelectric resonators has to be optimized. In this paper, optimization approach of this phase difference in the design process is proposed. The effectiveness of this approach was confirmed by water-pool experiments.
Children’s recognition of American English consonants in noise
Authors: Nishi Kanae , Lewis Dawna E. , Hoover Brenda M. , Choi Sangsook , Stelmachowicz Patricia G.
Published: May 2010

In contrast to the availability of consonant confusion studies with adults, to date, no investigators have compared children’s consonant confusion patterns in noise to those of adults in a single study. To examine whether children’s error patterns are similar to those of adults, three groups of children (24 each in 4–5, 6–7, and 8–9 yrs. old) and 24 adult native speakers of American English (AE) performed a recognition task for 15 AE consonants in /ɑ/-consonant-/ɑ/ nonsense syllables presented in a background of speech-shaped noise. Three signal-to-noise ratios (SNR: 0, +5, and +10 dB) were used. Although the performance improved as a function of age, the overall consonant recognition accuracy as a function of SNR improved at a similar rate for all groups. Detailed analyses using phonetic features (manner, place, and voicing) revealed that stop consonants were the most problematic for all groups. In addition, for the younger children, front consonants presented in the 0 dB SNR condition were more error prone than others. These results suggested that children’s use of phonetic cues do not develop at the same rate for all phonetic features.