bluuebunny/crossref_metadata_2025 huggingface dataset:
Nondestructive microscopic concentration, separation, analysis of biomaterials in microfluidic space using acoustic radiation force for cellomics study
Authors: Yasuda Kenji
Published: October 2013

A method for noncontact handling of biological materials such as cells using acoustic radiation force could be incorporated in a fully automated microfluidic analysis system for cellomics studies. Benefits of acoustic radiation force are simple and compact design without moving parts, suitability for continuous concentration, separation and mixing in micrometer-sized spaces, and ready use in microchambers allowing contamination-free handling. Since this can be an advantage in biological applications for on-chip cellomics screening, such handling techniques using ultrasound are pursued. At the meeting, the following three applications are presented: (1) mixing, concentration and fractionation of biomaterials [K. Yasuda et al., J. Acoust. Soc. Am. 99, 1248–1251 (1996); 102, 642–645 (1997), Jpn. J. Appl. Phys. 34, 2715–2720 (1995); K. Yasuda, Sens. Actuat. B. 64, 128–135 (2000)]; (2) superposition method for improving concentrating efficiency [K. Yasuda, Jpn. J. Appl. Phys. 36, 3130–3135 (1997)]; (3) separation of different materials exploiting the competition between acoustic radiation force and electrostatic force [K. Yasuda et al., J. Acoust. Soc. Am. 99, 1965–1970 (1996); Jpn. J. Appl Phys. 35, 3295–3299 (1996), K. Yasuda, Jpn. J. Appl. Phys. 38, 3316–3319 (1999)].
Manipulation of flow fields using acoustic radiation pressure
Authors: Trinh Eugene H.
Published: October 2013

The accurate trapping and positioning of single drops and bubbles in outer host fluids is a capability that can be utilized to study the detailed fluid motion within these particles, as well as in the outer host fluid. The understanding of this motion and the ability to control its magnitude impacts the use of the mechanisms involved in mass and energy transport across the drop and bubble boundaries. We used acoustic radiation pressure generated by an ultrasonic field between 25 and 60 kHz in degassed water to trap centimeter-size air bubbles and to observe the correlation between the onset of capillary waves on the bubble surface and the generation of internal air flow inside the bubbles. The modulation of the ultrasonic field has also allowed the observation of coupling between the resonant bubble radial oscillation mode and the shape oscillation modes for smaller diameter samples. Other applications of radiation pressure combined with electrostatic levitation of charged drops will be discussed together with some applications in the field of crystal growth and liquid surface property measurements. [Work funded through NASA.]
Acoustic particle manipulation devices driven by resonantly excited, cylindrical structures
Authors: Kaduchak Gregory , Goddard Greg R. , Kwiatkowski Christopher S. , Sinha Dipen N.
Published: October 2013

An overview of acoustic particle manipulation devices that use resonantly excited structures as the displacement generators will be discussed. These devices rely on coupling of the structural modes of a hollow, cylindrical tube to the acoustic modes set up in its interior cavity. For practical applications, discussed for both particles in air and in liquids, the structural vibrations are tuned such that desired modal responses of the cavity are obtained. The effects on particle manipulation due to different internal configurations and symmetry-breaking of the cross-sectional geometry will be shown in experimental data and videos. Specific designs of these devices have demonstrated that they can be engineered into power-efficient assemblies. It will be shown that different structural and cavity modifications can be made to meet the resonance matching condition for several different azimuthal mode numbers. Material and geometry considerations for nonresonantly driven devices will also be discussed. Applications include sample positioning for real-time analysis in flow cytometers, and aerosol concentration and positioning for in-line aerosol detectors.
The influence of spread of excitation on the temporal modulation transfer function (TMTF) for sinusoidal carriers
Authors: Millman Rebecca E. , Bacon Sid P.
Published: October 2013

The improvement in modulation detection thresholds with increasing stimulus level has been attributed to listening on the high-frequency side of the excitation pattern, where the growth of excitation is more linear, or to an increase in the number of channels via spread of excitation. TMTFs were measured for sinusoidal amplitude modulation (SAM) applied to a 1-kHz sinusoidal carrier, whose level varied between 10 and 80 dB SPL. Modulation detection thresholds improved as the carrier level increased. To minimize the use of spread of excitation at a carrier level of 80 dB SPL, various tonal restrictors were used alone and in combination. The restrictors were presented continuously and their frequencies were 501, 801, 1210, or 1510 Hz. Only the combination of the 801 and 1210-Hz restrictors resulted in an increase in modulation detection thresholds to values comparable to those obtained at 30 dB SL. These data suggest that listening on the high-frequency side of the excitation pattern alone cannot account for better modulation detection thresholds at higher levels, and that spread of excitation above and below the carrier is required for optimal performance. [Work supported by NIDCD.]
Effects of talker variability on vowel recognition by cochlear implant users and normal-hearing subjects listening to cochlear implant simulations
Authors: Chang Yi-ping , Fu Qian-Jie , Fu Qian-Jie
Published: October 2013

Different talker characteristics can significantly affect speech recognition, especially under conditions of reduced spectral resolution. In the current study, single- and multi-talker vowel recognition was tested with both cochlear implant (CI) patients and normal-hearing (NH) subjects listening to CI simulations. CI users were tested with their everyday processors. NH subjects were tested using four-channel acoustic processors in which the envelope cutoff frequency (20, 160 Hz) and the carrier band (noise-band, sine-wave) conditions were varied. Results showed that CI users’ single-talker vowel recognition was significantly better than multi-talker recognition. Among the simulations, both single- and multi-talker vowel recognition was best with the 160 Hz/sine-wave processor. Also, single-talker performance was significantly better than multi-talker performance only with the 160 Hz/sine-wave processor; there was no difference between single- and multi-talker recognition with the 20 Hz/sine-wave or noise-band processor. While the effects of talker variability were less for the 20 Hz/sine-wave and noise-band processors, overall vowel recognition was also significantly lower. Listeners’ sensitivity to talker variability may indicate their ability to register the relative vowel space for individual talkers. Without sensitivity to talker variability, multi-talker vowel space may collapse, causing cross-talker differences to be confused with phonetic differences. [Research is supported by NIDCD.]
Dynamic characterization of golf equipment
Authors: Mase Tom
Published: October 2013

In the golf swing the shaft, head, and ball respond at different time scales. The shaft is swung from the top of the back swing to impact in less than a half second. In that time, the shaft loads and unloads in different ways for different shafts. Natural frequencies and mode shapes characterize different shafts uniquely making some shafts better than others for individual golfers. Shafts are benchmarked by measuring their stiffness profile along the length of the shaft. Knowing this, a shaft finite element model is generated from which the natural frequency is found. Shaft zone frequencies, an important fitting method, are cantilevered natural frequencies found from the stiffness profile. As for golf balls, their core and cover mechanical properties influence performance and feel. The loading of the golf ball occurs in 0.0005 s. Golf ball stiffness and damping properties are measured using DMA and universal testing machines. Distance balls have cores that are nominally twice as stiff as performance balls, making them feel harder to the golfer. Performance and distance balls also respond to strain rate changes differently. Ultimately, stiffness properties affect the initial velocity, spin, and launch angle which dictate the distance the ball flies.
Relations between native Spanish speakers’ perception and production of English vowels
Authors: Lydtin Kimberly A. , Bell-Berti Fredericka , Jacobson Peggy , Centeno José
Published: October 2013

This study is about the relation between native Spanish speakers’ perception and production of English vowels and their age of arrival (AoA) in the U.S. The participants were also grouped by dialect, Central American/Caribbean or South American Spanish. In a listening task, the participants identified the words in the set ‘‘heed, hid, head, had, hod, hawed, hood, who’d, hud, heard’’ and then produced four repetitions of each of the ten words for spectral and temporal analysis. Finally, they indicated their sensitivity to contrasts between the vowels of the English vowel pairs /i–I/, /I–ε/, and /æ-≳/, rating them from ‘‘very similar’’ to ‘‘very dissimilar.’’ The results of our acoustic analyses will be compared with the participants’ identification data to determine how the vowel space of L1 (primary language) affect the production and perception of L2, and also with the listeners’ sensitivity to the vowel–contrast pairs.
Why are non-native (L2) utterances longer than native-produced utterances?
Authors: Flege James E. , Hojen Anders
Published: October 2013

Research has repeatedly shown that utterances produced by non-native speakers are longer than those of native speakers, even when produced as rapidly as possible. The non-native speaking rate effect is known to be greater for late than early L2 learners, but may disappear for late learners when very short-duration L2 utterances are examined. This study examined the duration of English utterances produced by native English (NE) speakers and late native Spanish (NS) learners of English (n=20 each). For normal-rate utterances, durations were significantly longer for the NS than NE group for syntactically complex sentences (e.g., The boy saw that Gary forgot a box of pencils) but not simple sentences (Gary forgot a box of pencils) or noun phrases (a box of pencils). However, the NS-NE difference reached significance for all three utterance types at a fast rate. In Experiment 2, the NS group took longer than the NE group to produce the digit string 1 2 3 4 5 6 7 as rapidly as possible. Taken together, the results suggest that differences in both the articulation of L2 speech sounds and higher-order planning (including the formulation of syntactic representations) contribute to the nonnative speaking rate effect. [Work supported by NIH.]
Accuracy and variability in vowel targets produced by native and non-native speakers of English
Authors: Nissen Shawn L. , Smith Bruce L. , Bradlow Ann , Bent Tessa
Published: October 2013

The primary issue explored in this investigation concerned how accurately and consistently non-native, adult speakers learning English as a second language produce vowel targets when compared with native speakers. One possibility is that non-native speakers show average formant and duration values similar to those of native speakers but are nonetheless more variable across repetitions. Alternatively, they might be ‘‘off-target’’ but still reasonably consistent in such productions. A group of native speakers (3F and 3M) and a group of Mandarin-speaking non-native subjects who had recently come to the United States (3F and 3M) produced at least ten repetitions of each of 20 different English words embedded in a carrier phrase. The first two formant frequencies and duration were measured for seven different vowels. Preliminary findings suggest that the non-native speakers’ vowel formants were generally quite similar to those of the native speakers, whereas their vowel durations deviated from those of the native speakers. Moreover, the non-native speakers exhibited greater within-speaker variability in their vowel productions (across word repetitions) than the native speakers, as well as a greater range in vowel formants and durations across speakers. Findings will be discussed in reference to their implications for second language acquisition and foreign-accented speech perception.
Perceived accents and comprehensibility of native and nonnative English
Authors: Ikeno Ayako , Hansen John H. L. , Fox Barbara
Published: October 2013

This study investigates the relation between perceived accentedness and comprehensibility of utterances spoken by native and nonnative English speakers. Native and nonnative English listeners heard six types of stimuli: single words, 2–10-word utterances from native and nonnative English speakers. Listeners classified the stimuli as either native or nonnative English speech and transcribed some utterances. Overall, results from the classification and transcription tasks indicate that perceived native-ness or nonnative-ness does not directly correspond to good or poor comprehensibility, as measured by transcription scores. Some nonnative utterances were classified as native speech by both native and nonnative listeners, although the transcription accuracy was not necessarily high. In other cases, native speech was correctly identified as native; however, dialectal pronunciation variation seemed to contribute to low transcription accuracy in some cases. On the other hand, although the transcriptions were accurate, native speech was sometimes classified as nonnative. In other cases, nonnative utterances were correctly identified as nonnative, and the speech was transcribed accurately. These results suggest that familiarity with certain dialects or accents influences listeners’ perception and comprehension for both native and nonnative speech, and that perceived nonnative-ness may not be the main cause for nonnative speech to be less comprehensible.
The use of acoustic multipath for localization of sperm whales
Authors: Thode Aaron M.
Published: October 2013

Sperm whales produce impulsive sounds, or ‘‘clicks,’’ that are ideally suited for acoustic tracking. If a widely distributed passive acoustic array is available, then the relative time delays from a click’s direct path can be used to derive an animal’s location. There are many interesting circumstances, however, where deploying a wide-baseline 3D array geometry is either unavailable or impractical. In such situations acoustic reflections of clicks from the ocean surface and bottom can be used to effectively convert a few hydrophones into a wide-aperture array that permits localization in range, depth, and azimuth. In addition acoustic multipath, particularly surface reflections, can also simplify automated detection and tracking procedures, and permit a single hydrophone to be used to distinguish between multiple whales calling simultaneously. Reviewed here is recent research on how multipath effects detected on one or two hydrophones have been used to recover dive profiles of sperm whales in the Gulf of Alaska and the Gulf of Mexico. This information, in turn, has been used to explore whether the animals exploit multipath for their own purposes, to estimate signal directionality, and to observe how sperm whales remove fish from longlines. [Work sponsored by ONR, the Minerals Management Service, and the North Pacific Research Board.]
Fifteen years of long-range propagation experiments in the North Pacific
Authors: Spindel Robert C. , Worcester Peter F.
Published: October 2013

Over the last 15 years a series of long-range acoustic propagation experiments has been conducted in the North Pacific Ocean using various combinations of low-frequency, wide bandwidth transmitters and horizontal and vertical line array receivers, including a two-dimensional array with a maximum vertical aperture of 1400 m and a horizontal aperture of 3600 m. These measurements were undertaken to further our understanding of the physics of low-frequency, broadband propagation and the effects of environmental variability on signal stability and coherence. The first experiment in this series, which was conducted in 1989, combined a broadband, 250-Hz transmitter with a 3-km-long vertical receiving array 1000 km distant. The transmissions revealed a traditional SOFAR arrival pattern of steep, raylike time fronts in the early portion building to a crescendo of near-axial arrivals that cut off abruptly. The near-axial finale was found to be highly scattered, however, and included significant energy in the geometric shadow zone. The prevailing theory of scattering from internal-wave-induced sound-speed fluctuations predicted far more resolvable arrivals than were observed. These observations stimulated an intense research effort to reconcile data with theory. In this presentation we summarize the central issues these experiments have addressed, and identify the many still remaining unanswered questions.
Spatial coherence of acoustic signals measured during the 1998–1999 North Pacific Acoustic Laboratory (NPAL) experiment
Authors: Ostashev Vladimir E. , Voronovich Alexander G.
Published: October 2013

Little experimental data have been reported in the literature about spatial coherence of low-frequency sound waves propagating over megameter ranges in the ocean. In 1998–1999, the North Pacific Acoustic Laboratory (NPAL) carried out a comprehensive low-frequency long range sound propagation experiment with the use of the receiving billboard acoustic array. By signal-processing of the NPAL data, we calculated spatial coherence of the broadband acoustic signals (with 75 Hz carrier) after their propagation of about four thousand km in North Pacific. The results obtained are presented in this paper. First, the horizontal coherence of the NPAL signals is discussed. The results show that the horizontal coherence radius varies in the range 500–1000 m. This value is in a good agreement with predictions of a 3D modal theory of low-frequency long-range sound propagation in a fluctuating ocean. Secondly, the vertical coherence of the NPAL signals is presented. After averaging over several days of the experiment, the vertical coherence reveals non-monotonic dependence on the distance between hydrophones. Finally, the horizontal-vertical coherence is studied. This coherence rapidly degrades with the increase of vertical separation between hydrophones. [Work supported by ONR.]
Transverse horizontal spatial coherence of deep arrivals at megameter ranges
Authors: Andrew Rex K. , Howe Bruce M. , Mercer James A.
Published: October 2013

Predictions of transverse horizontal spatial coherence from path integral theory are tested for ranges from 2000 to 3000 km. A low-frequency (75 Hz) source bottom-mounted at depth 820 m near Kauai transmitted ‘‘m-sequence’’ signals over several years to bottom-mounted U.S. Navy horizontal line arrays in the North Pacific. The arrays acquired only the early, deep arrivals. Coherence lengths estimated from the datasets, on the order of 400 m, show good agreement with lengths calculated from theory. Both measurements and predictions show a dependence on path as well as path length. These coherence lengths correspond via a simple incoherent source model to about 1° in horizontal arrival angle variability. Estimates of scintillation index, log-amplitude variance, and variance of decibel intensity indicate that the fields were partially saturated. There is no significant seasonal variability in these measures. Scintillation index predictions from path integral theory also agree well, although theory identifies these fields as fully saturated. [Work supported by ONR.]
Comparison between ocean-acoustic fluctuations in parabolic-equation simulations and estimates from integral approximations
Authors: Flatté Stanley M. , Vera Michael D.
Published: October 2013

Line-integral approximations to the acoustic path integral have been used to estimate fluctuations due to internal waves. Approximations for the root-mean-square (rms) fluctuation and the bias of travel time, rms fluctuation in vertical arrival angle, and the spreading of the acoustic pulse out to 1000-km range are here compared to estimates from simulations that use the parabolic equation (PE). Integral-approximation (IA) estimates of rms travel-time fluctuations were within statistical uncertainty at 1000 km for the Slice89 profile, and in disagreement by between 20% and 60% for the canonical profile. Bias estimates were accurate for the first few hundred kilometers of propagation, but often disagreed beyond. The PE structure functions of travel time with depth were quadratic for vertical separations of 20 m or less, in qualitative agreement with the IA prediction. Pulse spreads in the PE results were much smaller than predicted by the IA estimates. Implications of these results will be discussed.
Eliminating unnecessary diffractive features in ocean sound-speed models for long-range acoustic propagation
Authors: Hegewisch Katherine C. , Cerruti Nicholas R. , Tomsovic Steven
Published: October 2013

A major focus of long-range acoustic experiments is the study of the properties of the ocean. In order to explore these properties, it is necessary to have an effective model of the ocean that is sufficient to understand the physics of the wave propagation. Large structures in the ocean cause refraction of the acoustic waves, while smaller structures cause diffraction. Since long-range time fronts are mainly due to refractive effects, adding diffractive features to a model does not significantly change the long-range wave propagation. However, such features cause important theoretical techniques based on refraction, e.g., ray methods, to be inaccurate and they also increase computational effort in the wave propagation calculations. A prescription to remove the diffractive features in an ocean sound-speed model is outlined and the effects on the time fronts is shown. This removal eliminates the ‘‘microfolds’’ in the phase space manifolds [discussed by Simmens et al. in J. Acoust. Soc. Am. 102, 239 (1997)] and improves the wave/ray correspondence. Therefore, it is necessary to remove diffractive structures from ocean models before attempting to use ray methods to understand long-range propagation. [Work supported by ONR.]
Sound fields and speech intelligibility in rooms
Authors: Roy Kenneth P. , Stowell John , Walter Mike , Schuepbach Mathew
Published: October 2013

A key objective in the architectural design of buildings is to choose building elements that provide both speech intelligibility within a space, and speech privacy between spaces. Standard measurement and evaluation methods per ASTM standards on speech intelligibility and privacy will be discussed as they relate to field measurements. Field data on the reverberant sound fall-off with distance from the source will be presented for a range of small to mid-sized rooms. The variation in reverberant sound within a space can result in an estimation error for the AI and PI between rooms. A possible approach to resolving this issue will be discussed.
Assessment of Architectural speech security of closed offices and meeting rooms
Authors: Gover Bradford N. , Bradley John S.
Published: October 2013

The degree to which converstions taking place within closed offices and meeting rooms are audible or intelligible to a listener outside the room depends on the listeners hearing ability, the talkers voice level, the sound attenuation afforded by the building, and the background noise at the position of the listener. Sensible assumptions can be made about the listeners ability so that signal-to-noise measures can be used to reliably indicate audibility or intelligibility. A survey of actual meetings was conducted to acquire estimates of typical voice and noise levels, which can be used in the prediction of security. In existing buildings, the background noise can be measured, leaving only the need to measure sound attenuation through the building. A new measurement prodcedure has been developed that accurately indicates the attenuation from within a source room to a single receiving point outside the room. The results of this procedure can be used to derive a reliable indicator of the level of speech security at the receiving point. This procedure is capable of handling localized weak spots (‘‘leaks’’ or ‘‘hot spots’’) in the partitions. An overview of the measurement and assessment procedures will be discussed.
A case study of speech privacy in healthcare and other closed-plan professional spaces
Authors: W. Good Kenneth
Published: October 2013

Speech privacy is of growing importance in everyday life. Most folks assume that their conversations will be confidential when the door is closed. The need for the measurement and rating of a room’s performance is driven by both consumer demand for respect of privacy, and by regulations such as HIPAA and GLBA. This case study will present field measurements of various professional spaces such as healthcare counseling, medical treatment rooms, and pastors’ offices and places of counseling in ministry.
Techniques for separating interfering blue and fin whale calls
Authors: Hursky Paul , Abawi Ahmad T. , Porter Michael B. , Hildebrand John A. , Wiggins Sean M. , Sauter Allan W.
Published: October 2013

Recordings of blue and fin whales were made at the Southern California Offshore Range (SCORE) in August 2003. In analyzing this data, previously successful tracking algorithms, based on time differences of arrival (TDOA) measured on geographically distributed hydrophones, were frustrated by the mutual interference between the shorter, broadband, but higher amplitude fin whale calls and the longer duration, narrow-band, blue whale calls. We present a series of progressively more powerful detectors designed to isolate these two types of calls, by zeroing in on specific features of these calls. Because the limited bandwidth of both types of calls presents a challenge to time delay estimation, we also present a comparison of a number of TDOA estimators, including correlation of suitably isolated time-series and spectral features. We apply these techniques to data from different years and geographic sites to assess previous anecdotal evidence of strikingly similar calls within groups of blue whales, despite the presumably wide range of physical characteristics among individuals within each group.
Studies of waveguide propagation effects on frequency properties of sperm whale communication signals
Authors: Sidorovskaia Natalia A. , Ioup George E. , Ioup Juliette W.
Published: October 2013

The Littoral Acoustic Demonstration Center (LADC) conducted a series of passive acoustic experiments for studying ambient noise environment and marine mammal (namely, sperm whales) acoustic phonations in the Northern Gulf of Mexico by long-term autonomous recordings of broadband acoustic signals on a single bottom-moored hydrophone. It was previously reported that extensive spectrogram analysis of sperm whale phonations revealed persistent null pattern in animal spectral signatures that could be associated with either waveguide propagation effects or with a uniqueness of an animal phonation apparatus. The previous modeling addressed the propagation effects on echolocation signals of deep-water foraging animals. It was demonstrated that the null patterns in the analyzed spectrograms could not be explained by the propagation effects for an animal echolocating at foraging depths. This paper presents the results of modeling waveguide propagation effects on spectral properties of sperm whale near-surface communication signals, codas, that could be associated with distinctive sequences of clicks repeatedly present in the LADC recordings. The possibility of the individualization of sperm whale phonations based on the frequency properties of click recordings on a single hydrophone is discussed. [Research supported by ONR.]
Brydes whale (balaenoptera edeni) sounds collected from autonomous hydrophones in the eastern tropical Pacific, 1999–2001
Authors: Heimlich Sara L. , Nieukirk Sharon L. , Mellinger David K. , Dziak Robert , Matsumoto Haru , Fowler Matthew
Published: October 2013

An array of seven autonomous hydrophones, deployed within 12 N 8S and 95 110W, continuously recorded the frequency band 1–110 Hz from November 1999 to November 2001. Four low frequency sound types were observed, similar to Brydes whale vocalizations previously reported [E. Oleson et al., Mar. Mammal. Sci. 19, 407–419 (2003)]. Two averaged 2.5-s duration and were commonly high amplitude sounds that exceeded the sampling frequency. Both had a distinct tone averaging 18.6 and 25.4 Hz, respectively, several frequency-modulated higher tones that resembled harmonics but were not, and often an initial short broad band pulse which overlapped the tonal components. Two were lower amplitude sounds that typically began with a single constant-frequency upper tone, averaging 36.6 Hz, 1.1-s duration, and 28.7 Hz, 1.1-s duration, respectively. Sometimes, an overlapping lower tone followed 0.7 s later, lasting 1.6 s and averaging 21.4 and 15.3 Hz, respectively. Occasionally the upper and lower tones alternated two or more times, with decreasing amplitude on each repetition. Differences in seasonal occurrence and geographic distribution amongst the four types were found. These results support the use of passive acoustics as a technique for examining existing and proposed stock definitions.
Acoustic observations of longline depredation by sperm whales
Authors: Thode Aaron M. , Straley Janice M. , O’Connell Tory M. , Burgess William C.
Published: October 2013

Sperm whales have learned to take sablefish off longline gear in the Gulf of Alaska. Over the past two years the Southeast Alaska Sperm Whale Avoidance Project (SEASWAP) has collected biopsy and photo-ID data concerning longline depredation, via collaboration with local fishermen in Sitka, AK. In 2004, in collaboration with SEASWAP, sets of autonomous acoustic recorders were attached to the anchor lines of several longline deployments, effectively converting the fishing gear into a vertical acoustic array deployed 200 m beneath the surface. The fishing vessels then left the area, leaving the acoustic instruments behind to monitor the region. Several hours later, typically the next morning, each vessel would return and begin hauling in the gear, a procedure that was also recorded by the instruments. In May 2004 an interaction of two sperm whales with the F/V Cobra was recorded. It was found that the animals started producing sounds within 20 min of the longline recovery and continued being extremely vocally active throughout the recovery. Acoustic multipath was exploited to estimate the range and depth of the whales. [Work sponsored by the North Pacific Research Board.]
Consistency in received echo characteristics with an echolocating Tursiops truncatus
Authors: Ibsen Stuart , Au Whitlow , Nachtigal Paul , Breese Marlee
Published: October 2013

In this experiment the dolphin was asked to perform a discrimination task between two simulated targets. The echoes from these targets were created using a phantom echo generator which replicated the actual echo characteristics of solid spherical stainless-steel or brass targets. The system provided full knowledge of each click produced by the dolphin and the corresponding echo received by the dolphin. During the discrimination task the dolphin used a range of clicks that differed widely in peak frequency and bandwidth. However, the echoes that were returned to the dolphin showed significantly less variability in these characteristics. The dolphin in this study carefully maintained consistency in just a portion of the full bandwidth of its clicks, the region that was both within the dolphin’s hearing range and had the best reflectivity off the target. The rest of the click bandwidth outside this region showed a higher degree of variability. The dolphin most likely demonstrated less control over these frequency regions because they were outside its hearing range or did not provide the dolphin with nearly as much information.
The spatial context of free-ranging Hawaiian spinner dolphins producing acoustic signals
Authors: Lammers Marc O. , Schotten Michiel , Au Whitlow W. L.
Published: October 2013

An important requirement for understanding the function of animal signals is the ability to determine the context in which they occur. To improve our understanding of how dolphins use acoustic signals in the wild a three-hydrophone towed array was used to investigate the spatial distribution of Hawaiian spinner dolphins (Stenella longirostris) relative to each other as they produced whistles, burst pulses and echolocation clicks. Groups of 10 to 60+ animals were recorded while they traveled and socialized in nearshore waters off Oahu, HI. Broadband recordings up to 62.5 kHz were obtained using a PC-based multi-channel system with simultaneous analog-to-digital converters. Signaling animals were localized using time of arrival difference cues on the three channels. Localized whistles produced closely in time typically originated from individuals spaced widely apart (10–100+ m), supporting the hypothesis that whistles play a role in maintaining contact between animals in a dispersed group. Multiple burst pulses, on the other hand, usually came from individuals spaced closer to one another (5–20 m), suggesting they function as a more intimate form of signaling between adjacent individuals. The spacing between echolocating animals was variable.
Will acoustically enhanced nets reduce odontocete gillnet bycatch because they are better sound reflectors?
Authors: Mooney T. Aran , Au Whitlow W. L. , Nachtigall Paul E.
Published: October 2013

Tens of thousands of odontocetes are caught annually as bycatch in gillnet fisheries worldwide. Of particular interest are bottlenose dolphins and harbor porpoises, both caught in U.S. waters. One method to potentially reduce this incidental-take is to use nets that are easier for echolocating marine mammals to detect. These acoustically enhanced gillnets are designed to reflect odontocete sonar signals better than regular nylon nets. They have shown to reduce bycatch. Whether or not this is due to increased acoustic reflectivity remains to be determined. We measured the target strength of cod and monkfish gillnets, including those enhanced with barium sulphate, an iron oxide, using dolphin- and porpoise-like echolocation signals. From the target strengths we then predicted the detection distances of the nets by the respective animals. It was determined that at reasonable distances bottlenose dolphins should be able to detect all nets. But because of lower probable source levels, harbor porpoises may not be able to detect any gillnet before it becomes entangled. Stiffness of the nets was also quantified and experimental nets proved to be greater in stiffness than regular nets, thus likely a significant factor in reducing odontocete bycatch.
The timbre space of the Chinese membrane flute (dizi): Physical basis and psychoacoustical effects
Authors: Tsai Chen-Gia
Published: October 2013

The Chinese membrane flute (dizi) has a membrane covering a hole in the wall of the instrument between the mouth hole and the uppermost finger-hole. The membrane is driven by the acoustic pressure in the pipe, producing rich harmonics through its nonlinearity. The dizi timbre is multidimensional and varies with pitch. Inhomogeneity of the dizi timbre is well known by musicians. It reflects a general aesthetic tendency in traditional Chinese music that a skillful musician should produce a variety of timbre with a solo instrument. The major spectral features of dizi tones, i.e., (1) formants, (2) the predominance of odd harmonics, and (3) harmonic-to-subharmonics ratio at high frequencies, can be explained by a Duffing oscillator model of the membrane. They constitute the three dimensions of the dizi timbre space, where the ‘‘trajectory’’ of the changing timbre of a dizi melody is embedded. Psychoacoustical effects associated with them are discussed, including (1) spatial effects due to abrupt brightness changes, (2) multi-pitch effect due to the predominance of upper odd harmonics, and (3) roughness induced by subharmonics.
Vibrational modes of pyen-gyoung (Korean chime stone) and pyeon-jong (Korean chime bell)
Authors: Yoo Junehee , Rossing Thomas D.
Published: October 2013

Pyeon-gyoung, chime stone, and Pyeon-jong, chime bell, have been allocated as a set of instruments in Korean traditional court music and Confucian ceremony. Pyeon-gyoung is a set of 16 L-shaped chime stones covering one and one-third octaves and pyeon-joung is a set of 16 almond-shaped bronze chime bells, one octave lower than pyeon-gyoung. The nominal frequencies increase with the thickness of the stones and bells. The vibrational mode frequencies in a pyeon-gyoung and pyeon-jong have been studied. The frequency ratios of the modes in stone chimes are smaller than those of marimbas. The modal shapes of the lowest and highest stones, mapped by TV holography, by scanning with an accelerometer and animated by STAR, are shown.
Acoustic matching of the bars and resonators of the Indonesian gender
Authors: Wheeler Paul
Published: October 2013

The gender is a 14-bar metallophone with bamboo resonators used in the Indonesian gamelan. The 14 bronze bars (with stiffening ridges on top of the bars) are carefully tuned to one of three pentatonic scales. The bars are strung together and spaced above 14 bamboo resonator tubes housed in a wooden frame. The bamboo tubes are roughly the same length and diameter, however the knot in the bamboo pipe is in different locations, creating closed pipes of different lengths. Fine tuning of the tubes is achieved by placing rocks or sand in the bottom of the tubes. This paper describes an acoustic study of the gender barung. Tuning of the bars across the octaves was within 15 cents (with one exception), showing great care in the construction and tuning of the bars. Tuning of the resonator tubes, however, was much more divergent, showing less consideration for the actual frequencies of the resonators. Tuning of the resonators to match the bars is left for the player by adding materials to the resonator tube.
Extracting the frequencies of the pinna spectral notches from measured head-related impulse responses
Authors: Raykar Vikas C. , Duraiswami Ramani , Yegnanarayana B.
Published: October 2013

Experimental data are available for the Head-related impulse response (HRIR) for several azimuth and elevation angles, and for several subjects. The measured HRIR depends on several factors such as reflections from body parts (torso, shoulder, and knees), head diffraction, and reflection/diffraction effects due to the external ear (pinna). Due to the combined influence of these factors on the HRIR, it is difficult to isolate features thought to be perceptually important (such as the frequencies of pinna spectral notches) using standard signal-processing techniques. Signal-processing methods to extract the frequencies of the pinna spectral notches from the HRIR are presented. The techniques are applied to extracting the frequencies of the pinna spectral notches from the publicly available HRIR databases. A brief discussion relating the notch frequencies to the physical dimensions and the shape of the pinna is given. [The support of NSF Award ITR-0086075 is gratefully acknowledged.]
Assessment of accumulated structural damage with the help of linear and nonlinear acoustic techniques
Authors: Kin Yulian , Zhou Chenn , Roads Eric , Parsons Bernard , Sutin Alexander , Shaubal Pinakin , Huang Frank
Published: October 2013

The paper presents applications of linear and nonlinear acoustic techniques for reliable detection of early stages of fracture, fatigue, and other damage, as well as investigation of structure-sensitive acoustical signatures for fundamental material research. The experimental investigations were conducted on steel samples, carbon bricks, and pavers under different types of loading (static and cycling regimes) in laboratory conditions and, in field, to detect progressive changes in a blast furnace wall. A special effort was made to investigate the changes of acoustical response after aging of materials, but before a warning of damage (necking, crack initiation, crazing, disbonding, surface flow, etc.) is physically observed in service life. Measurements were made periodically as structural damage accumulated, but no visible surface crack formation was observed during the tests. The described techniques can be used for the assessment of structure integrity, remaining life, and adjustment of maintenance schedules in applications as diverse as reactor containment wall damage, inspection of damage in buildings, bridges, furnaces, pipelines, aging aircraft, etc. [Support of Indiana 21st Century Fund is greatly appreciated.]
Nasalization, neutralization, and merger in English front vowels
Authors: Liu Jerry
Published: October 2013

Before a velar nasal, a tense/lax contrast in the front vowels is generally considered to be conflated to only the set of lax vowels in American English. However, Ladefoged (2001, A Course in Phonetics) states that many younger Americans pronounce ‘‘sing’’ with a vowel closer to that in ‘‘beat’’ rather than to that in ‘‘bit.’’ This paper examines front vowels produced by nine young Californians before the velar nasal to document whether or not the vowel, in fact, raises. Two outcomes are possible: (1) a front and raised vowel intermediate between its tense and lax counterparts (which we call neutralization) or (2) a lax vowel (which we call merger). Further, the pattern for both high- and midfront vowels is examined. The results demonstrate a consistent pattern of neutralization (i.e., an intermediate vowel) for both the high- and mid-vowels, the latter a previously unattested environment for this pattern of raising before velar nasals.
Movement duration and movement stiffness in long and short consonants
Authors: Lofqvist Anders
Published: October 2013

This study examined the relationship between movement duration and movement stiffness in speech. Stiffness was measured as the interval from movement onset to peak velocity. The speech material consisted of long and short Japanese consonants produced by native speakers. A magnetometer was used to track articulatory movements. For the lower lip, the velocity of vertical closing movement for bilabial consonants was measured, while the speed of the tongue tip was measured for dental stops and fricatives. Results from six subjects show that the lower lip movement duration was longer for the long consonants, which also had a lower stiffness than their short cognates. The results also show higher correlations between duration and stiffness for the short consonants. The results for the tongue tip showed more variability across and within subjects, although the overall trend was similar to the one found for the lower lip. In addition, all correlations between tongue tip movement duration and stiffness were high. These results extend earlier work on the same relationship, where it has mostly been studied across variations in speaking rate. They also suggest potential differences between articulators and between stops and fricatives. [Work supported by NIH.]
Perturbation and compensation in speech acoustics using a jaw-coupled robot
Authors: Tiede Mark K. , Guenther Frank H. , Perkell Joseph S. , Zandipour Majid , Houle Guillaume , Ostry David J.
Published: October 2013

Observations were made in three speakers of compensation in formant trajectories in response to jaw perturbations during utterances with the general form /siyCVd/, as in ‘‘see red.’’ Custom dental prostheses were used to help immobilize the head (upper jaw) and couple a computer-controlled robotic device (lower jaw). A 3-Newton perturbation force was applied to the jaw during one out of every five repetitions, selected at random, with half of the perturbations applied downward and half upward. Perturbations were triggered from jaw opening (for CV) exceeding a threshold relative to clench position. Audio (at 10 kHz) and jaw position (at 1 kHz) were recorded concurrently. Individual tokens were extracted using the perturbation threshold for alignment. Formants computed over these intervals show initial deviation from control trajectories and then compensation that begins 60–90 ms after perturbation. Since jaw position does not recover its unperturbed trajectory, compensation presumably is effected through modified tongue movements. The observed behavior is compatible with the function of the DIVA model of speech motor planning, in which corrective motor commands are computed in response to errors between anticipated and produced sensory (auditory and somatosensory) consequences. [Research supported by NIDCD.]
A simple transformation of the environment eliminates standard PE phase errors
Authors: Rypina Irina I. , Udovydchenkov Ilya A. , Brown Michael G. , Beron-Vera Francisco J.
Published: October 2013

It is shown that, in range-independent sound channels with a single sound speed minimum, the environment can be transformed in such a way that solutions to a standard parabolic wave equation in the transformed environment are asymptotically equivalent to solutions to the Helmholtz equation in the original environment. This equivalence is demonstrated using both ray- and mode-based wavefield expansions. Reasons that equivalence between solutions to the Helmholtz equation and the parabolic wave equation can only be asymptotic will be briefly reviewed. [Work supported by ONR and NSF.]
A very simple transformation of the environment significantly reduces Thomson–Chapman PE phase errors
Authors: Udovydchenkov Ilya A. , Rypina Irina I. , Brown Michael G. , Beron-Vera Francisco J.
Published: October 2013

In a range-independent environment with a single sound speed minimum, a transformation of the environment is available which guarantees that solutions of the standard parabolic wave equation in the transformed environment are asymptotically equivalent to solutions of the Helmholtz equation. In this paper an approximate transformation, to be used in conjunction with the Thomson–Chapman parabolic approximation, is described. Advantages of the approximate transformation over the exact transformation are its simplicity and the fact that it can be used in environments with multiple sound speed minima. Travel time errors, relative to the corresponding Helmholtz equation rays, associated with this approximation in typical deep ocean environments grow approximately linearly in range at a rate of approximately 0.1 ms/Mm. [Work supported by ONR and NSF.]
LOAPEX: The long-range ocean acoustic propagation experiment
Authors: Mercer James A.
Published: October 2013

This paper describes the recent long-range ocean acoustic propagation experiment (LOAPEX) and presents initial results. LOAPEX was conducted between 10 September and 10 October 2004, and was closely coordinated with two other experiments, BASSEX and SPICEX. LOAPEX provided low-frequency broadband acoustic transmissions to vertical hydrophone arrays covering most of the deep ocean water column, and to horizontal hydrophone arrays surrounding the Eastern North Pacific Ocean. Two of the primary objectives are to explain the strong acoustic arrivals that are received in the deep ocean shadow zone, and to better understand the roles of scattering and diffraction in general. Transmission paths to the vertical hydrophone arrays varied from 50 to 3200 km. [Work supported by the Office of Naval Research, Code 321OA.]