bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic and articulatory measures of prosodic convergence in a cooperative maze navigation task
Authors: Lee Yoonjeong , Gordon Danner Samantha , Parrell Benjamin , Lee Sungbok , Goldstein Louis , Byrd Dani
Published: November 2016

Convergence effects have been found in many aspects of communication between speakers in conversation. This study examines how phonetic properties of each speaker’s prosodic structure differ before, during and after participating in a cooperative maze task. Using two NDI electromagnetic articulatory tracking systems simultaneously, we recorded speakers of American English in dyads (one male dyad & one female dyad). Acoustic measurements included: 1) sentence durations, 2) phrase-final lengthening, 3) occurrence frequency of sentence-final boundary tones (percentage H%), and 4) peak F0 values in sentence-final words. Articulatory boundary strength measures for word-final consonant(s) articulations included: 1) movement durations, 2) displacement, and 3) time-to-peak velocity in phrase-medial and phrase-final positions. Speakers exhibited distinct phonetic patterns before the cooperative maze task. However, conversing speakers showed convergence effects in prosodic boundary strength, choice of boundary tone, and quantitative characteristics of boundary tone. Convergence effects persisted in the speech of one or both members of each dyad even after conversation has ended. Our findings raise the possibility that qualitative and quantitative aspects of prosody can be modeled as arising from a single system of control and that this system of prosodic structuring can show coupling effects across speakers. [Work supported by NIH.]
Explicit imitation and working memory
Authors: Morris Miranda R.
Published: November 2016

Much research a has been conducted in regards to implicit imitation, that is, phonetic imitation that occurs largely without a speaker’s knowledge. However, explicit imitation, which occurs intentionally, has received far less attention. While it is observed that individuals vary in explicit imitative abilities, i.e., some individuals’ speech shift more towards a given target voice than others, the factors that contribute to these differences have yet to be identified. The current study investigates individual differences in explicit imitation by exploring the correlation between explicit imitation and working memory, the memory involved in short term conscious processing. Subjects participated in a baseline word reading task as well as an imitation task which involved repeating the same words aloud after hearing prerecorded stimuli from a Texan speaker. Additionally, subjects completed a reading Span task in order to measure working memory capacity and determine the effect of working memory on degree of explicit phonetic imitation. The degree of proportional phonetic shift towards the target speaker was correlated with Span scores in order to determine what link exists between explicit imitation and working memory on the level of the individual.
Circular synthetic aperture sonar images and aspect dependent spectral properties of solid elastic cubes
Authors: Bollen Viktor , Marston Philip L. , Plotnick Daniel S.
Published: November 2016

While cubes may not be commonly found underwater, studying their aspect and material-dependent backscattering mechanisms may be useful in leads to understanding the scattering physics of other objects. Two solid cubes, made of either steel and or brass, were insonified in water using a circular synthetic aperture sonar (CSAS) system; Fourier based techniques were used to reconstruct target images. Identifiable backscattering mechanisms include edge-diffraction and elastic responses. Rayleigh waves, a class of surface elastic waves, are excited near a material specific incident angle (Rayleigh angle) that depends on the material of the cube. Those waves may retroreflect from the edges of the cube’s facee edges of the cube’s face in such a way as to enhance backscattering [K. Gipson and P. L. Marston, J. Acoust. Soc. Am. 105, 700-710 (1998)]. The steel cube displayed a strong Rayleigh wave response, easily visible in CSAS images; for the smaller brass cube that said mechanism was relatively subtle. Aspect dependent spectral properties can bewere extracted from the images or directly from the time-domain records. When the cube’s top ridge is slanted vertically, an aspect angle dependent splitting in the low frequency spectrum can bewas observed and associated with edge diffraction. The experimental results were compared to Kirchhoff-Integration based simulations, which did notthat don’t include elastic responses. [Work supported by ONR.]
Moving away from the phase center approximation in micronavigation for synthetic aperture sonar
Authors: Gerg Isaac
Published: November 2016

In many respects, the difficult problem of synthetic aperture sonar is motion estimation of the platform since there exists no reasonably priced inertial measurement unit which can meet the location accurately requirements needed to generate high resolution imagery. Many beamforming codes estimate their motion using a displaced phase center technique. This technique is popular but makes some approximations that break down in long range systems and in significant motion environments. In this paper, we discuss the motion estimation algorithm used in ASASIN, a time domain back projection beamformer developed at Penn State Applied Research Laboratory. Our motion estimator assumes displaced phase centers but moves away from the phase center approximation. Rather than estimating the vehicle position delta ping-to-ping independently, we estimate the vehicle’s velocity and acceleration through all pings in 3 space. We use Google’s Ceres solver to solve the resulting non-linear equations and additionally add a regularization term to deal with missing and bad data samples. Finally, we show imagery formed using our algorithm.
Laboratory measurements of a phase shift in the reflection from a water-mud interface due to water column variability
Authors: Venegas Gabriel R. , Wilson Preston S.
Published: November 2016

Harbor basins and certain continental shelf environments experience significant variability due to tides, surface heating, currents, and other oceanographic processes. Dynamic processes such as these can cause substantial sound speed and density fluctuations in the water column over short time periods, which are often unknown to sonar users. Such variations are not critical over high-velocity bottoms such as sand, but can produce significant changes in how sound interacts with low-velocity fine-grained sediments. High levels of variability and a low-velocity bottom, such as mud, can therefore present challenges in applications including mine detection, port protection and shallow water sonar. At certain penetration angles, temporal variations in the water-to-sediment sound speed ratio can cause 180 degree phase shifts in the reflected field, which in turn produces waveguide propagation and target scattering field variability. To begin to understand these processes, laboratory measurements of plane wave reflection were obtained from a water-mud interface while varying salinity and temperature of the water. Results indicate that the dynamic nature of sound speed ratio at the ocean bottom can cause significant effects in shallow water environments with muddy bottoms. [Work supported by ONR.]
Stevens acoustic research in the Hudson River
Authors: Sutin Alexander , Salloum Hady
Published: November 2016

Stevens Institute of Technology conducted numerous acoustic tests in the Hudson River. The main instrument was Stevens Passive Acoustic Detection System (SPADES) that consists of a simple array with 5 hydrophones and that was initially developed for diver detection. Later, we collected a large library of acoustic signatures of various vessels and developed numerous algorithms for detection, tracking and classification. We present a brief review investigating acoustic applications in the Hudson River, including: Acoustic tomography tests were conducted for measuring the river currents. The difference of time of flight to emitter and receiver placed near the opposite bank of the River was used for calculating the current. Numerous tests were conducted for estimating the Impulse Response and its variation that can be used for prediction of reliability and operating distances for underwater acoustic communication. Noise measurements from passing boats were used for estimating the acoustic attenuation in a wide frequency band. Several other possible future researches may include: Time Reversal Acoustic Focusing for diver deterrence. Active/Passive acoustic fence for diver detection. Bubble curtain for the suppression of underwater noise from a pile drive.
Comparison of scattering mechanisms for excitation of axial modes by surface sources
Authors: Farrokhrooz Mehdi , Wage Kathleen E.
Published: November 2016

The vertical spectrum of low-frequency ambient noise in deep water contains significant contributions from distant shipping. Distant noise is concentrated at angles around broadside that are associated with the low order modes. Near-surface sources cannot excite the low modes directly. Dashen and Munk suggest three mechanisms for transferring energy from high modes to low modes: internal wave (IW) scattering, downslope conversion, and excitation at high latitudes where the sound channel intersects the surface. Dashen and Munk conclude that slope conversion is the most likely due to the weakness of IW scattering and the lack of shipping traffic at high latitudes. Commenting on their IW analysis, Dashen and Munk note that they are not totally convinced by their theoretical results and admit that IW scattering may have a significant effect. This talk compares the IW scattering and downslope conversion mechanisms for transferring surface source energy to the low modes. IW scattering is modeled using transport theory [Colosi and Morozov, JASA 2009] and compared to parabolic equation and coupled mode simulations. Results show that IW scattering from a large number of ships can produce vertical spectra comparable to those obtained through downslope conversion. [Work supported by ONR.]
Did humpback whales go missing off Maui, Hawaii? A comparison of song activity between the 2014/15 and 2015/16 breeding seasons
Authors: Kügler Anke , Lammers Marc O. , Zang Eden J. , Kaplan Maxwell B. , Mooney T A.
Published: November 2016

Each winter, thousands of humpback whales (Megaptera novaeangliae) migrate from their high latitude feeding grounds in Alaska to mate and calve in the shallow tropical waters around the Main Hawaiian Islands. Population estimates suggest that up to 10,000 animals winter in Hawaiian waters, making up more than half of the total North Pacific stock. However, in the 2015/16 season, anecdotal reports from commercial operators and researchers tell of an unusually low number of whales compared to previous years off the island of Maui. To examine this issue, data from long-term passive acoustic monitoring with autonomous Ecological Acoustic Recorders (EARs) during the 2014/15 and 2015/16 seasons off the west coast of Maui were analyzed using male chorusing levels as a proxy for relative whale abundance. Root-mean-square sound pressure levels (SPLs) were calculated to compare low frequency acoustic energy (0-1.56 kHz) between both seasons. The data showed that chorusing levels dropped in early January 2016. Although levels subsequently increased again until they peaked in February as expected, SPLs remained lower than in 2014/15 throughout the remaining season. These results suggest that the number of singing males was indeed lower during the 2015/16 season off west Maui and that future monitoring is warranted.
The correlation between the local environment and gray whale behavior as tracked using a sparse hydrophone array in Monterey Bay National Marine Sanctuary
Authors: Guazzo Regina A. , Hildebrand John A. , Wiggins Sean M. , D'Spain Gerald L. , Weller David W.
Published: November 2016

Gray whales (Eschrichtius robustus) make one of the longest annual migrations of any marine mammal. While the seasonal periodicity of the migration and related travel corridors have been well-studied, little is known about how these whales use acoustics while migrating. Acoustic array processing is a powerful tool to localize and track vocalizing whales without disrupting their behavior. Concurrent with the NOAA Southwest Fisheries Science Center visual and infrared gray whale census, four hydrophone-recorder packages with sites separated by approximately 2 km in 58 to 110 m water in Monterey Bay National Marine Sanctuary offshore of Granite Canyon, California, recorded from November 2014 to June 2015. An automatic call detector identified gray whale M3 calls in the dataset. Spectrogram cross-correlation was used to measure the time-difference-of-arrival of these calls and estimate the location of the calling animal. These localizations provide gray whale swimming and calling behavior and indicate changes on diel and seasonal time scales. Results from 15 high-quality tracks show calling gray whales swimming at a mean speed of 1.97 m/s with a range of 1.18 to 2.54 m/s. Acoustic detections and tracks are compared with environmental parameters to investigate how gray whale behavior relates to their physical environment. These results are necessary for understanding the cues gray whales use to navigate from their feeding grounds offshore of Alaska to their breeding grounds in Baja California.
Low-frequency propagation and noise in the intertidal zone
Authors: Martin James S. , Rogers Peter H. , Bhandiwad Ashwin , Colleye Orphal , Sisneros Joseph
Published: November 2016

Measurements of ambient noise and short-range propagation (<2m) were made in the intertidal zone with water depths ranging from 50 to 80 cm using vector sensors. The sites selected for the measurements were known nesting areas for plainfin midshipman (Porichthys notatus). Males of this species produce continuous acoustic advertisement calls with fundamental frequencies in the 70 to 100 Hz range. The temporal and spectral structure of these calls must convey information regarding the source’s range, direction, and/or fitness over the maximum detectable range in a complex environment. Both fundamental and harmonic components appear to be above a rapid low-frequency increase in the noise floor due to local wave motion and below the frequency range of several observed noise transients at times with modest wind speeds (<5 mph) and small wave heights (<20cm). There is little evidence of significant propagation differences between specific frequencies within the band of interest.
Passive acoustic monitoring of fishes and a crustacean using a towed hydrophone in Tateyama bay
Authors: Takahashi Ryuzo , Akamatsu Tomonari , Imaizumi Tomohito , Matsuo Ikuo
Published: November 2016

Passive acoustic monitoring is useful to observe presence of marine organisms such as marine mammals, fishes and crustaceans. We aimed to estimate the distribution of fishes and crustaceans using a towed hydrophone. A range-wide passive acoustic monitoring was conducted in Tateyama bay in Japan using R/V Takamaru (61t) on July, September and November in 2015 of day and night. The towed hydrophone (Towed Aquafeeler, AquaSound Inc., Japan) was used for the observation. The vessel cruised 5 knot on 5 lines to cover the focal survey area (N 35°020’—N 35°02’ and E 139°46—E 139°51). Recorded data with frequency from 100Hz to 20 kHz were analyzed. Recorded fish sounds have dominant frequency between 200 Hz and 1500 Hz and duration between 0.1 s and 2.1 s. Crustacean sound shows dominant frequency as 3 kHz–20 kHz with the duration of 10 ms—20 ms. Using these features, number of fish sounds was counted automatically using custom-made MATLAB program. Large number of the sounds were recorded in the nighttime than in the daytime. Most frequently received month was July. Both of the fish and crustacean sounds were observed in shallow water (<30m) showing acoustic presence map.
Comparison between trawl volume and composition and acoustic backscatter
Authors: Copeland Adrienne M. , Au Whitlow W. , Polovina Jeffrey
Published: November 2016

Active acoustics is an important tool to quantitatively assess the densities of pelagic organisms. While it is an important tool, it is hard to determine the organism composition recorded acoustically especially in oligotrophic waters where mixed organism assemblages are common. One such mixed stock in the Hawaii Islands is the Deep Scattering Layers (DSL). These layers are made up of micronekton (small squid, fish, and crustaceans) which may be an important component linking primary producers with higher trophic levels. Trawling can identify the composition in these layers but this tool can be costly and unable to sample as much area as active acoustics. Many organisms in the DSL diurnally migrate to the surface between 0 and 200 m to feed. We surveyed these organisms using active acoustics and trawling collected in June 2013 and March 2014 on the R/V Oscar Elton Sette. We compared the composition of organisms, volume by functional group, and total volume in the trawl with the acoustic backscatter to determine the relationship between trawl and active acoustic data. We determined that the acoustic densities changed as a function of the trawl composition and volume potentially allowing for the ability to exclusively use acoustics in the future.
Studying deep diving odontocetes potential prey fields' densities and size structure in Hawaii using a DIDSON imaging sonar
Authors: Giorli Giacomo , Au Whitlow W.
Published: November 2016

Deep diving odontocetesodontocetes feed in the deep ocean on mesopelagic squid and fish. The distribution of these prey are poorly known but does affect the distribution of deep diving odontocete predators. Hence, it is important to collect data on the density and composition of potential prey to identify deep sea habitats that attract deep diving odontocetes. We used a DIDSON imaging sonar to investigate the density and size structure of mesopelagic animals along the Kona coast of Hawaii, where beaked, sperm and pilot whales are regularly seen. Data were collected at multiple stations during three research cruises by lowering the sonar in the water column to sample at different depths and monitoring the mesopelagic biomass with an EK60 38 kHz echosounder. Foraging activity of whales was monitored at few stations using passive acoustic recorders and a towed array of hydrophones. We were able to count and size 7068 pelagic animals. Density and size varied in space, with higher densities and bigger animals at the offshore stations. The DIDSON was effective at detecting targets bigger than 10 cm, a size range that includes potential prey of deep diving odontocetes. Preliminary data suggest differences may exists in habitat selection by each deep diving odontocetes.
Multi target positioning system using Gold code pingers applied to Japanese squid in Japan Sea
Authors: Uchida Keiichi , Sasakura Toyoki , Kamoshida Takashi , Miyagi Aki , Fujikawa Yasuo , Kamiya Keiichi , Inada Hiroshi , Miyamoto Yoshinori
Published: November 2016

To study the effect of light on Japanese squid (Todarodes pacificus) behavior, we developed a new ultrasonic biotelemetry system that can simultaneously observe and measure multiple targets. We tested the system on 40 squids in open water. Each squid was attached with a Gold code pinger (AquaSound Inc.) that transmits single frequency signals of multiple codes (IDs). By using the combination of 32 kinds of Gold code sequences, we succeeded to develop a receiving system that can simultaneously track 40 pingers. In the field test, 40 squids attached with the Gold code pingers were released simultaneously into open water and signals were recorded from three fishing boats for a maximum of six hours. The underwater positioning of the squids was calculated based on the “reverse cross-bearing” method by using the cross points from each direction against the target obtained by two boats. With the addition of depth data obtained by the pressure sensor installed in each Gold code pinger, we succeeded to measure the 3D positions of all 40 target squids. Considering the movement of boats by wind and tide, the positions of all three boats were measured every second using the GNSS (FURUNO Electronics Co., Ltd.).
Modeling reflection and scattering by deep-ocean turbidites
Authors: Jackson Darrell , Tang Dajun
Published: November 2016

Turbidites are commonly found in deep ocean sediments and are composed of multiple thin layers of fine and coarser sediments, the coarser sediments being deposited by turbidity currents. Although acoustics is a unique means to quantitatively probe the physical and geophysical properties of turbidites, research on this subject is still limited. The work of Gilbert and of Holland and Muncill has shown that this layering can cause acoustic reflection to be very strong, with bottom loss less than that expected for hard seafloors. We examine this problem further, looking at the effect of layering on penetration into the seafloor and also considering scattering by roughness of the inter-layer interfaces. It is found that penetration can be severely limited in some cases, and that this behavior can be understood as a form of Anderson localization. Prospects for inversion of broadband, vertical-incidence data are considered. [Work supported by ONR.]
Doppler sonar measurements of bedload sediment transport: Yes there’s a signal, but can it be quantified?
Authors: Zedel Len , Hare Jenna , Hay Alex , Wilson Greg
Published: November 2016

It has been demonstrated that Doppler sonar measurements of apparent bottom velocity in rivers is correlated with bedload transport. We explore the degree to which this measurement can be quantified using a field deployable multi-frequency (1.2-2.2 MHz), bistatic Doppler sonar system that provides three-component velocity profiles over a ~30 cm interval with ~5 mm resolution at a rate of 50 profiles/sec. Model simulations of system performance demonstrate that the estimates of bed movement are proportional to sediment flux but scaling to actual sediment flux would require an empirical fit. In order to explore the system capability under actual field conditions, a series of experiments was undertaken at the St. Anthony Falls Laboratory (SAFL). The SAFL facility provides a 1.8 m deep, 2.75 m wide flume tank that allows flow rates of order 1 m/s over a mobile bed and where the bedload transport can be measured by sediment traps built into the flume system. We report on preliminary results from trials made at SAFL.
Model-based design of multibeam sonar system
Authors: Kuroda Jun , Kaname Motohiro
Published: November 2016

Multibeam sonar is a technique used to many applications in offshore activities, e.g. oceanographic survey, fish finder and sound navigation in maritime. Sonar consists of integrated system of components, which are acoustic transducers, electrical transmitter receivers, and signal processing circuits. Numerical prototyping by model-based design (MBD) is widely employed to develop of various instruments, which are also useful to design algorithm and configuration of sonar. A sonar system is divided roughly into two system categories, that is to say, category 1: acoustic transducers and acoustic fields, and category 2: electrical transmitters, receivers, and signal processing circuits. Design of the category 1 needs numerical simulation of sonic waves reflected by targets. One issue for MBD is to study a high speed and low-cost computation method to simulate echo signals. Numerical computation methods, such as finite-element method (FEM), boundary-element method (BEM) and finite-difference-time-domain method (FDTD), require lots of computation resources to solve large acoustic field. Multibeam sonar is usually used to targets which are away from transducers. Therefore, equations to simulate transmitted and received sonic wave can be simplified by the far field approximation. This paper proposes a numerical simulation method of acoustic echo signals between transducers and targets for MBD.
Relationship between auditory degradation and fricatives/affricates production and perception in elderly listeners
Authors: Yasu Keiichi , Arai Takayuki , Kobayashi Kei , Shindo Mitsuko
Published: November 2016

Elderly people often complain that they struggle with consonant identification when listening to spoken language. In previous studies, we conducted several experiments, including identification tests for young and elderly listeners using /shi/-/chi/ (CV) and /ishi/-/ichi/ (VCV) continua. We also recorded production of such CV and VCV syllables. For the CV stimuli, confusion of /shi/ as /chi/ increased when the frication had a long rise time. The degree of confusion increased when auditory property degradation was observed such as threshold elevation in high frequency. In the VCV stimuli, confusion of /ichi/ as /ishi/ occurred for a long silent interval between the first V and C with auditory property degradation. In the present study, we analyzed the utterances of those CV and VCV syllables and measured the duration of frication and silent interval. The direction of the boundary shift in the perception of fricatives and affricates by auditory degradation was consistent with that of production. We found that degradation of auditory properties affects both perception and production of fricatives and affricates in elderly people.
A speech synthesizer of Japanese saves patients' voices
Authors: Arai Takayuki , Kawahara Shigeto , Homma Musashi , Yoshimura Takaki
Published: November 2016

“MyVoice,” free speech synthesis software for Japanese, developed by one of the authors, is widely used to save many patients' voices in Japan. We lose our voice for various reasons. Amyotrophic Lateral Sclerosis, or ALS, is an example. When an ALS patient has difficulty breathing, Tracheotomy becomes an option, and the patient loses the ability to speak. Laryngectomy is another example. By using “MyVoice,” patients can keep communicating using their own voice even after losing that ability. To facilitate this, patients record utterances with their voice before surgery. The recording is designed to minimize time and load of patients as much as possible, by including Japanese basic mora set so that potentially any word can be concatenated from the recorded sounds. The graphical user interface of this software is well-designed so that therapists as well as the patients' family and friends can also use it with a minimum of effort. In fact, we often hear heart-warming stories of making “MyVoice.” “MyVoice” continues to rescue patients’ voices and we will continue making improvements to it in the future.
Use of data hiding in aerial sounds for accessibility
Authors: Nishimura Akira
Published: November 2016

This article reviews previous technologies for aerial acoustic data transmission, namely, audio data hiding, acoustic modems, and a hybrid of the two. These technologies can provide an information channel to convey index data for static text messages or data for text messages to assist people who are deaf or hard of hearing. The payload bitrate of these technologies ranges from several bits per second for long distances (>100 m) to hundreds of bits per second for short distances (<1 m). Previous studies have mainly focused on developing methods for embedding and encoding information into aerial sounds. However, few works have evaluated actual aerial transmission in the presence of various disturbances, such as reverberation and reflections, transfer functions of loudspeakers and microphones, nonlinear distortions in loudspeakers, background noise, and Doppler effects. Therefore, in this study, evaluation methods for these acoustic data transmission technologies are proposed and discussed. In addition, practical applications are discussed regarding the use of the technologies as a means of accessibility for people with speech and language disabilities.
Optimization of sphingosylphosphorylcholine concentration for detection of cytoskeletal changes in malignant pancreatic cells using high-frequency ultrasound
Authors: Carter Caitlin , Sanjinez Dolly , Marvel Mandy , Doyle Timothy E.
Published: November 2016

The biomechanical properties of cells can be greatly influenced by modifications of the cytoskeleton of the cell. Cytoskeletal modifications can often be linked to disease and disease pathways. Cancer metastasis has been previously associated with the cytoskeletal modifications that are induced by the addition of sphingosylphosphorylcholine (SPC) to panc-1 cells. SPC is a bioactive lipid that reorganizes keratin filaments in the cytoskeleton into a perinuclear shape that enables cell mobility. The maximum effect of SPC on the keratin reorganization has been previously observed as being concentration dependent, with 5-10μM concentration being optimal as observed through keratin immunostaining. In this work, high frequency ultrasound was used to observe the SPC induced keratin reorganization through an ultrasound signature. Ultrasound measurements were obtained using 10μM SPC and ~17μM SPC concentrations. Significant time-dependent changes in the ultrasound measurements were observed in the higher concentration of SPC as compared to control cell cultures that were not treated with SPC. In contrast, the lower concentration of SPC did not show visible changes in the ultrasound measurements taken. Future work will include optimizing a more specific concentration of SPC for observing changes in the ultrasound measurements taken of panc-1 cells.
Dynamics of an acoustically driven liquid-gas interface
Authors: Patterson Brandon , Johnsen Eric
Published: November 2016

Interactions between acoustic waves and liquid-gas interfaces occur in a variety of applications, including diagnostic ultrasound of the lung. We hypothesize that, because of the sharp density gradient at the fluid discontinuity, acoustic waves may generate sufficient baroclinic vorticity to appreciably deform liquid-gas interfaces. This nonlinear effect has been studied for shock-accelerated interfaces, i.e., the Rictmyer-Meshkov instability; however, it is not describable through traditional, linear acoustic methods and is not well studied for acoustic waves. To investigate our hypothesis, we simulate an inviscid, compressible fluid system with acoustic waves impinging from water into air. We find that acoustic waves capable of deforming the interface during the wave-interface interaction period will deposit lasting baroclinic vorticity along the interface, capable of driving deformation that continues long after the passage of the wave. We use dimensional analysis to describe the dependence of the late-time interface growth on the deposited vorticity. Lastly, we show results to demonstrate that for acoustic waves with properties relevant to diagnostic ultrasound encountering a water-air interface, nearly all of the vorticity is generated in gas-dominated fluid. We explain this using an order of magnitude analysis.
All-in one small modular transducer system for ultrasound therapy
Authors: Yoshinaka Kiyoshi , Takeuchi Hideki , Toyoda Shingo , Sasaki Akira , Azuma Takashi , Takagi Shu
Published: November 2016

We developed new concept all-in one small modular transducer system for ultrasound therapy. Focus position control of HIFU (High Intensity Focused Ultrasound) with multi-elements phase delay control is very popular in clinical application. However, multi-elements driving amplifiers are very large size like a large refrigerator. So, we adopted a direct drive amplifier system for the multi-elements modular transducer. The modular system has some advantages compared to conventional systems. It can be reduced the energy loss of the connecting cable between the transducer element and the amplifier. Other advantages are below. Free placement of module transducer elements like a patient specific body line. Easy maintenance of each element. Easy design change to reduce the manufacturing time. The modular transducer system is composed of four blocks. The first module is multi-channel transducer elements. The second module is multi-channel direct drive amplifier system. The third module is a name-card size multi-channel phase delay signal generator with the phase delay signal set memory bank. The fourth module is a phase delay signal set generating software with a personal computer. It can transmit the signal set to the third module. We manufactured the prototype very small all-in one modular transducer system for ultrasound therapy.
Surgeon assessment versus laboratory measurement: brain tissue mechanics quantified by expert opinion
Authors: James Sheronica L. , Howell Mark , Wang Qi , Clement Gregory T.
Published: November 2016

Transcranial ultrasound (tUS) is a plausible means of measuring motion of the brain due to traumatic force or structural abnormalities. However, limited data in the literature on the mechanical properties of human brain tissue make it practically impossible to develop a mechanically realistic ultrasound phantom that can mimic the brain under these conditions. The present study aimed to determine, by indirect qualitative assessment, the stiffness of in-vivo brain tissue. Six surgeon examiners under blinded conditions physically examined 16 gelatin-based tissue phantoms (0.020-0.095 g/mL) to determine which sample best matched the stiffness of brain tissue in-vivo. Ten cylindrical phantom samples, acoustically matched to human brain tissue, were prepared based on the examiners’ responses (0.030±0.008 g/mL), and stress-strain behavior was characterized under compression up to 50% strain. The average compressive stress at 50% strain was 10.3±1.4 kPa. These results correlate well with those previously reported in the literature, and add a practical measure of brain stiffness to the paucity of information available on human brain tissue mechanics. Furthermore, it is potentially an initial step in developing mechanically realistic models of structural disorders of the brain and traumatic brain injury to evaluate theories on the brain’s mechanical behavior under these circumstances.
Bio-acoustic levitational assembly of heterocellular multilayer constructs for tissue engineering
Authors: Bouyer Charlene , Chen Pu , Demirci Utkan , Padilla Frederic
Published: November 2016

Many tissues are comprised of multiple heterocellular layers, where interlayer cell communications between heterogeneous cell populations are essential to sustain normal tissue functions. Mimicking such natural organization presents a challenge to tissue engineering, and few methods are available to bioengineer heterocellular multilayer constructs in vitro. We have developed a bulk acoustic levitation (BAL) technique to assemble multilayer 3D neuronal constructs from homogenous neural progenitor l. We present here a novel approach to build heterocellular multilayer tissues by combining BAL and layer-by-layer assembly. Cells are levitated into several layers within fibrin prepolymer solution by bulk acoustic waves and immobilized in a fibrin hydrogel layer via gelation. Several hydrogel units can then be stacked subsequently, each unit with a distinct cell type, to form a single hydrogel construct. We demonstrate the bioengineering of a heterogenous multilayer construct composed of three different cell types (wild-type—mCherry and eGFP HeLa cells) spatially distributed in a single 3D hydrogel. This novel approach enables rapid formation 3D multilayer structures in minutes with tunable interlayer spacing, layer composition and thickness, and is potentially useful to bioengineer homogenous and heterogeneous multilayer cell organization for tissue engineering. 1 Bouyer et al. (2015) Adv. Mater. 28:161-7
Study on ultrasound irradiating conditions for apoptosis induction in the rat glioma cell line C6
Authors: Hiroaki Sugamata , Takaaki Satou , Shinichi Takeuchi
Published: November 2016

We’re paying attention on ultrasound irradiation the cancer treatment method using apoptosis of a cell self-destruction program. We think that our method can be expected as a new effective and safety treatment method, if the cells were induced into apoptosis by using ultrasound. In this experiment, ultrasound irradiation experiments, to rat glioma cell line C6 were performed. The experiments were performed by using the standing wave type ultrasound irradiation system at frequency of 150 kHz. Also, we estimated the apoptosis induction after ultrasound irradiation by using Annexin V Assay Kit. We examined apoptosis induction of the cells after 8 hours of ultrasound irradiation. The fluorescence of FITC and PI was observed in the same cells, when ultrasound was irradiated to the cells by applying the continuous sinusoidal wave with voltage of 150 Vpp. It was suggested that the cells wave in the late stage of apoptosis and the stage of necrosis. When irradiated with applied voltage of 213 Vpp, only the fluorescence of FITC could be observed in the same cells. It was suggested an early stage of apoptosis. We're planning to perform the experiment, using the focused ultrasound irradiation system at frequency of 1.75 MHz in near future.
Acoustic characterization of stethoscopes using auscultation sounds with synchronized electrocardiography recordings as test signals
Authors: Nowak Lukasz J. , Nowak Karolina M.
Published: November 2016

The modern stethoscopes implement different technologies and features in order to better transmit the sounds from the inside of a body of a patient to the doctor’s ears. However, the objective evaluation of the actual influence of various solutions on the acoustic parameters of the diagnostic device is difficult. This is due to the fact, that the acoustic coupling between the body of an auscultated patient and the chest piece of a stethoscope can significantly alter the determined parameters, and due to the variable and noisy nature of the auscultation signals. The present study introduces a detailed methodology for acoustic characterization of the stethoscopes using the auscultation sounds as test signals. Information obtained from additional, synchronized electrocardiography measurements is used to extract short, specific fragments of recordings, defined as acoustic events. Analysis of the spectral characteristics of many acoustic events allows to compare the acoustic properties of various stethoscopes and to estimate the measurement uncertainty. The determined statistical acoustic parameters of the auscultation signals are presented, showing relatively large variation even within a single patient examination. The example results concerning various commonly used acoustic stethoscopes are introduced, showing discrepancies between the declared and the actual acoustic properties.
Shear wave elastography reveals dispersion regimes in porous materials
Authors: Aichele Johannes , Zemzemi Chadi , Lescanne Maxime , Catheline Stefan , Roux Philippe
Published: November 2016

Ultrasound shear wave elastography is a well established tool for characterization of biologic tissues. While it has found application in various medical disciplines such as oncology and urology its feasibility for pneumology still has to be shown. We provide experimental results of ultrasound shear wave elastography of porous materials in phantoms and ex-vivo lung tissue. Phantom foams immersed in water show a strong phase velocity dispersion with increasing frequency. Two regimes can be identified in the dispersion curves in the investigated frequency range from 50 to 700 Hz. These experimental results are in reasonable agreement with the theory of porous materials. The results from water-filled phantom foams are compared to gelatin-filled phantom foams. Finally, the phantom study is compared to surface waves dispersion curves of porcine lungs obtained with an ultra-fast optical camera and the first results of ex-vivo shear wave elastography in porcine lung. Ultrasound shear wave elastography is standard in non-porous organs such as muscle, liver, and breast tissue. Its application to porous materials could offer a noninvasive and nonionizing alternative for lung characterization.
High frequency and high intensity ultrasonic transducers for medical applications using oriented piezoelectric thick films by hydrothermal method
Authors: Ishikawa Mutsuo , Uchida Yosuke , Tabaru Marie , Kurosawa Minoru , Kosuge Nobuyuki , Sugiyama Hideto
Published: November 2016

Recently, high-frequency ultrasonic transducers are proposed for medical applications using piezoelectric crystal. In this case, it is known that the high piezoelectric constant and the higher limitation of vibration velocity are important for high power application. Normally, the piezoelectric ceramics has limitation due to maximum vibration velocity. Thus it is very difficult to radiate for high intensity ultrasound with nonlinear acoustics due to the limitation of maximum vibration velocity. Therefore, we tried to develop a very high intensity and high frequency ultrasonic transducer using hydrothermal KNbO3 thick film. The piezoelectric constant was over 80 pm/V and the vibration velocity of thickness mode of KNbO3 thick film was 2.5 m/s or over at 20 MHz. This maximum vibration velocity is twice of reported piezoelectric materials. Then, a radiation sound-pressure from the prototype ultrasonic transducer with KNbO3 thick film was measured. The result of radiation ultrasound was 4 MPa or over in a water. It is very high intensity at high frequency. Consequently the hydrothermal KNbO3 thick film is usefulness for medical applications. The reason for why it is able to radiate for high intensity ultrasound at high frequency will be discussed in this presentation.
Ultrasound for nuclear reactors
Authors: Tittmann Bernhard R. , Reinhardt Brian , Suprock Andrew
Published: November 2016

Ultrasonic methods offer the potential for Structural Health Monitoring of critical components in nuclear reactors. These efforts have been limited by ultrasonic transducers incapable of performance under high temperatures and/or irradiation conditions. Here we report on piezoelectric transducers designed, fabricated, tested and optimized to perform in harsh environments. Test capsules with piezoelectric transducers were fabricated with Aluminum Nitride (AlN), Zinc Oxide (ZnO), and Bismuth Titanate (BiTi) as the active elements. Measurements were performed in the MIT Reactor for 18 months. The transducers experienced an integrated neutron fluence of approximately 8.68 E + 20 n/cm2 for n >1 MeV, temperatures in excess of 420 °C, and a gamma fluence of 7.23 Gy/cm2. The AlN transducer acoustically coupled to a Kovar cylinder gave acceptable pulse-echo data throughout the test. We show a summary of the test results. Thus the feasibility of ultrasonic transducers in a nuclear reactor has been established and opens the door to leave-in-place sensors for in-reactor conditions and materials. [The authors gratefully acknowledge support from the Department of Energy under the ATR-NSUF program.]
Defect position and size estimation in billet by ultrasonic transmission method using a small number of transducers
Authors: Miyamoto Ryusuke , Mizutani Koichi , Ebihara Tadashi , Wakatsuki Naoto
Published: November 2016

For a steel billets inspection, we have proposed defect detection and size estimation from time-of-flight (TOF) profile by ultrasonic transmission method with linear scanning. In this method, a defect is detected by deviation of TOF of transmitted wave caused by diffraction at the defect. In addition to defect detection, defect size can be estimated from deviation of TOF because TOF is affected by defect size. However, deviation of TOF is also affected by the depth of the defect, which cannot be precisely estimated only by linear scanning of a pair of transducers. In this study, we propose defect position and size estimation using multiple pairs of transducers and validity of the method was evaluated. By using multiple pairs of transducers, TOF of inclined paths, where transducers is not facing each other are also obtained as well as parallel paths, so that the position of defect can be estimated. As a result, the defect position could be estimated by using two pairs of transducers and defect size could also be estimated correctly compared with conventional linear scanning method.
Force feedback microelectromechanical microphones for high performance applications
Authors: Boorman Owain L. , Harris Nicholas , Wright Matthew C.
Published: November 2016

Microelectromechanical System (MEMS) condenser microphones are widely used because of their low cost, small size, high sensitivity, and wide bandwidth. For certain specialist applications, however, they are still out-performed by the best conventional condenser microphones, which have greater bandwidth and dynamic range, but at higher cost and larger size. The sensitivity, and hence, signal-to-noise ratio of smaller MEMS microphones can be increased by using two perforated back-plates instead of one. The maximum amplitude is limited by membrane excursion, which leads to nonlinearity and, ultimately, failure. The use of force feedback holds the promise of avoiding these problems by holding the membrane at its equilibrium position while measuring the force required to do so. Previous attempts to accomplish this using a Sigma-Delta modulator have had only limited success in terms of signal-to-noise ratio, bandwidth and stability. Instead we propose to use an Electro-Mechanical Phase Locked Loop (EMPLL) to overcome these limitations. We will present lumped-parameter and Finite Element models of the performance of such a microphone, and discuss the challenges associated with its fabrication. [This work was supported by Roke Manor Research Limited.]
Design of distributed mode loudspeaker through evolutionary structural optimization
Authors: Shirouzu Goki , Samejima Toshiya
Published: November 2016

The distributed mode loudspeaker (DML) is a flat panel loudspeaker that consists of a thin plate as a diaphragm and several driving exciters. In designing the DML, a number of flexural resonance modes are encouraged to be excited. Thereby, complex vibration is produced in the diaphragm, and the sound field around the DML is diffuse at high frequencies. In the DML design procedures, choosing proper aspect ratio of the diaphragm, driving points, and suspension points are important to deliver flexural resonance modes as many as possible. In this research, the authors focus on the shape of diaphragm. The authors try to optimize the diaphragm shape that delivers more equalized interval between the natural frequencies of the diaphragm so that it does not have many degenerated modes. To achieve this, Evolutionary Structural Optimization (ESO) method, which is one of structural topology optimization methods, is adopted. The scheme is based on the idea that, by gradually removing inefficient materials, the structure shape evolves toward optimum one. This method enables us to select the best shape of the diaphragm from shapes given in the process. Trial designs demonstrate that the ESO method is effective in designing the diaphragm of the DML.
Spatial post-filter estimation for speech enhancement in the specific area using a pair of microphone arrays
Authors: Yoshimizu Takuto , Kataoka Akitoshi
Published: November 2016

Suppression methods using the beamformer and the Wiener post-filter by microphone array has been proposed. However, these methods are hard to suppress noise on the environment, such as the desired source is surrounded by noise. We propose the suppression method using a pair of microphone arrays arranged in different positions on the environment, such as the desired source is surrounded by noise. We can get different information of sound by using two microphone arrays. We make the post-filter using its different information of sound. This method enhance the desired source to be the sound source in the specific area. Therefore, we divide the room into nine areas by using two microphone arrays. By estimating the cross spectrum between two microphone arrays of each partition area, we make the post-filter to noise suppression. By the experiment results under actual environment, we confirmed that this method was higher in noise suppression performance than MVDR using one microphone array that is general beamformer.