bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasound hearing and response in alosine herrings: A short history of the pure and applied research to date
Authors: Schilt Carl R.
Published: October 2013

In the early 1990s it was reported that downstream-migrating American shad (Alosa sapidissima) avoided a sonar-sampling beam with fundamental frequency over 150 kHz. Since then there has been a considerable body of laboratory and field work to determine which fishes have such hearing capacity, what the hearing limits are, what the hearing mechanisms may be, what might have led to selection for such capacity, and the utility of such stimuli to control the local distributions of fishes with such ultrasonic hearing. So far it seems that ultrasonic click aversion is limited to one subfamily of primarily anadromous herrings (family Clupeidae; subfamily Alosinae). The capacity to hear very high clicks and the propensity to swim away from the stimulus direction has led to experiments in shad protection, especially in hydropower and other industrial environments, which have been promising. This talk will review the history of both the pure and applied science on alosine herring ultrasound response and suggest possible research and application strategies for the future.
Continental shelf fish choruses in Australian waters
Authors: McCauley Robert D. , Cato Douglas H.
Published: October 2013

Almost everywhere the authors have sampled ambient noise on Australia’s continental shelves, in tropical and temperate waters, evening choruses have been recorded. Chorus maximum frequency varies from a few hundred Hz to a few kHz and may result from different species, but the consistency of the timing and similar chorus nature suggests that different source species are following similar behavior. Individual chorus signals are comprised of single pops or clicks of <200-ms duration, similar to those described from fish. We hypothesize that these chorus sources are nocturnally active fishes that mainly forage in the water column at night. In the Perth Canyon, Western Australia, shelf break choruses centered at 2 kHz have been measured since 1992. Here each evening the chorus begins shortly after dusk, reaches a maximum around 2 hours post dusk, drops to a lower level, rises again predawn, and then disappears during the day. Canyon net sampling through the water column has only recovered fish of the family Myctophidae as potential chorus sources. Long sea-noise time series records from the Canyon indicate significant seasonal trends in chorus levels and differences between years, possibly indicating that chorus activity reflects secondary productivity.
Distribution of static pressures on the skin surface of parallely swimming fish
Authors: Anraku Kazuhiko , Matsuoka Tatsuro , Watanabe Kenji
Published: October 2013

Hydrodynamic static pressures on the body surface of fish generated by conspecifics parallely swimming were measured in a flume tank, and they were compared with those generated by changing the position of two individuals under different flow velocities. Two dead common carp (BL=20 cm), fixed in 20% of formalin, were used. Pressure was measured by a manometer connected to the ends of three aluminum pipes (inner diameter=3 mm), which were inserted perpendicularly to the body axis from right to left in the control fish. The openings of the pipes were located on head, trunk, and caudal regions, and each was on the infraorbital or trunk canal lateral lines. The target fish was moved on the horizontal XY plane using a traverse device. Although pressures changed depending on the regions measured, changes of pressure according to position and current velocity were relatively low in the caudal region. The absolute values of the pressure increased as flow velocity increased, and decreased with an increase in the distance between individuals. Relative positions when the maximum pressure changes were observed at each flow velocity did not change, indicating that pressures were largest when the maximum body width of the conspecific is closest.
Swimbladders under pressure: Anatomical and acoustic responses by walleye pollock
Authors: Horne John K. , Barbee David , Sawada Kouchi , Abe Koki , Sadayasu Kazuhiro , Takao Yoshimi
Published: October 2013

Pressure influences echo intensities of swimbladdered fish through changes in swimbladder volumes and surface areas. Volume reduction is expected to correspond to Boyle’s law (volume ∝pressure−1) but the resulting deformation in swimbladder surface area will largely determine target strength at geometric scattering frequencies. Dorsal and lateral radiographs of juvenile walleye pollock (Theragra chalcogramma) in a pressure chamber were used to image swimbladders from ambient to a maximum of 5-atm pressure. As pressure increased, dorsal swimbladder surface areas decreased at a constant rate among the three individuals. Swimbladder volume reduction rates were similar among individuals but less than that predicted by Boyle’s law. Compression of swimbladders occurred dorsal-ventral, anterior-posterior, and laterally. Resulting swimbladder shapes became more spindlelike as pressure increased. KRM predicted target strengths at 38 and 120 kHz decreased more rapidly at 3 atm above ambient than at lower pressures. [Work supported by ONR and NRIFE.]
Target strength and behavior of swimming juvenile southern bluefin tuna in a cage estimated by echo-trace analysis
Authors: Abe Koki , Takao Yoshimi , Sadayasu Kazuhiro , Sawada Kouichi , Amakasu Kazuo
Published: October 2013

Echo-trace analysis (ETA) was applied to echoes from juvenile southern bluefin tuna (Thunnus maccoyii, SBT) swimming in a cage. The experiments were conducted offshore Esperance in Western Australia, using a split-beam echosounder operating at 70 kHz. The dimensions of a cylindrical cage were 7 m in diameter, 20 m in depth, and 8.5 cm mesh size of a net. A transducer was set at the center of a cage. The samples of SBT were caught by trolling near the study site. The age classes were 1 or 2 years old that were ranging 45 to 82 cm in fork length. Only one SBT was put into a cage at a time in order to obtain single echoes from one fish. As the swimbladder of juvenile SBT was not gas-filled in this stage, its target strength (TS) was much lower than TS of a same-size fish with gas-filled swimbladder. Because of low TS values, there were some difficulties to obtain high quality echo-traces continuously. So, preselections of high signal-to-noise and noninterference echoes from the echogram were needed before applying ETA. Swimming velocities and TS patterns in dorsal aspect were estimated by ETA.
Target strength estimation of the large jellyfish Nemopilema nomurai
Authors: Hirose Miyuki , Mukai Tohru , Iida Kohji , Hwang Doojin
Published: October 2013

The jellyfish Nemopilema nomurai, which reaches up to 2 m in diameter and 200 kg in weight, has occurred in large numbers in the Sea of Japan during the last several years and has had a negative effect on coastal fisheries in this region. Data on the abundance and distribution of jellyfish are needed to forecast when and where they will occur in coastal areas. Acoustic techniques are commonly used to study the distribution and abundance of fish and zooplankton because these techniques can survey large areas relatively quickly. However, before such surveys can be conducted, the acoustic characteristics of the target species must be known. In this study, the density of and speed-of-sound in live jellyfish were measured to clarify their acoustic characteristics using a theoretical scattering model. Jellyfish density was measured using the dual-density method, while the speed of sound was measured using the time-of-flight method. The acoustic characteristics were estimated with the distorted-wave Born approximation (DWBA) model using these material properties and the shape of free-swimming jellyfish. The results demonstrate the feasibility of investigating the abundance and distribution of jellyfish using acoustic methods. [Work supported by JSPS and KOSEF Core University Program on Fisheries Science (FiSCUP).]
Using acoustic backscatter to determine the size distribution of channel catfish in a commercial pond
Authors: Heffington John , Chambers James , Heikes David , Pomerleau Steve , Stone Eric
Published: October 2013

With increasing seafood demand, aquaculture is poised to become a major growth industry in the United States. In particular, channel catfish represents an approximately $400 million industry. Pond management strategies, however, are compromised by high fish densities with large size distributions that result from years of continuous culture without a total harvest. Recent work has been presented on the Aquascanner SONAR system, which evaluates the total biomass of the pond but is less effective in determining the size distribution. To address this shortcoming, research colleagues at the University of Arkansas Pine Bluff are using a subsample seine net. Their method involves pulling a trawl across the pond to obtain a sample of the fish and manually weighing the fish in a time-consuming process to provide the size distribution. The work presented here attempts to use acoustic backscatter to determine the size distribution of the fish in lieu of the manual weight measurements. After being seined, the fish are allowed to swim back into the pond through a restrictive pipe and are pinged acoustically to determine their target strength and thus size. The experimental design of the system and results will be discussed. [Work Supported by the USDA.]
Target strength of Sargassum plant with vesicles containing gas
Authors: Minami Kenji , Hamano Akira , Nakamura Takeshi , Takao Yoshimi , Miyashita Kazushi
Published: October 2013

Information about the target strength (TS) of a vesicle is important to estimate the acoustic scattering of Sargassum plants. Experimental TS (TSe) of a vesicle was obtained at 70 and 200 kHz using quantitative echo sounders in a freshwater tank (10×10×15 m). The TSe of ten vesicles examined here were −56.88–51.68 dB at 70 kHz and −60.30–-50.90 dB at 200 kHz. The TSe′s of small vesicles were 2.56−−3.70 dB higher at 70 kHz than at 200 kHz, suggesting that these small vesicles were affected by the airbladder resonance. Theoretical TS (TSt) was estimated by airbladder−scattering models to confirm this effect. The gas radii of 418 vesicles (containing the experimented ten vesicles) were measured using a soft x−ray system and applied to the theoretical models. Their radii were 0.52−−6.00 mm; calculated TSt matched with TSe. According to the theoretical model, the vesicles were not affected by the resonance when argument ka is ka>1 (where k is the wave number and a is the radius). However, the vesicles were affected by the resonance when ka<1. That fact indicates that small vesicles (a is 1.22−−2.38 mm) at 70 kHz were affected by the resonance.
Target strength of a mesopelagic fish Maurolicus japonicus at 38 and 120 kHz
Authors: Fujino Tadanori , Yasuma Hiroki , Miyashita Kazushi , Sadayasu Kazuhiro , Abe Koki
Published: October 2013

Target strength (TS) of Maurolicus japonicus was examined at 38 and 120 kHz using experimental measurements (at 38 kHz) and theoretical swimbladder scattering models. Experimental measurements showed that the average TS for dominant size (32.1 to 34.8 mm standard length) were −60.5 to −56.7 dB, and the effect of the fish orientation on TS was slight. These results coincided with the model estimation, proving that swimbladder models are valid to estimate the TS of M. japonicus. The slight effect of the fish orientation on TS was presumed due to the oval shaped swimbladder with high aspect ratio, which is relatively little to the wavelength. This is a merit because tilt angle is usually a major source of TS variation. However, a little swimbladder would cause acoustic resonance at low frequencies, which leads to insatiability on TS according to depth change. Using the resonant model, relationships of the TS and standard length were estimated for depth 50, 100, 150, 200, and 250 m at 38 and 120 kHz, respectively. While TS at 120 kHz showed little change according to depth, TS at 38 kHz changed with depth and showed larger TS than 120 kHz for each size.
Target strength pattern measurement of krill (Euphausia pacifica) and measuring limits in a small tank
Authors: Sawada Kouichi , Mukai Tohru , Amakasu Kazuo , Abe Koki , Ishii Ken
Published: October 2013

Euphausia pacifica is an extremely important species for Japanfs northeast coastal fisheries and a key species for ecosystems in the northwest Pacific Ocean. Target strength (TS) of krill information have been required for acoustic surveys; they constitute a scale factor that is used to convert acoustic estimates of abundance. A precise TS pattern measurement system was constructed in a small tank. Target strength patterns of a target are measurable in the angle range of 60 deg at 1-deg steps. First, TS values of the thinnest fishing line with 53-mm diameter were measured as it was planned for use in tethering krill. TS measurement limits were also confirmed by measuring echo signals and noise signals. Maximum TS of the fishing line was −95 dB and the measurement limit was −98 dB at the frequency of 200 kHz with 10 dB of signal-to-noise ratio (SNR). Second, we confirmed the validity of the target suspension method. The thinnest fishing line was penetrated into the krill body to tether it between two vertical fishing lines. Finally, TS patterns of 12 live krill were measured and compared with theoretical calculations using distorted wave Born approximation. Both agreed well.
Acoustic studies investigating the distribution and abundance of krill in critical blue whale habitat in the Monterey Bay submarine canyon
Authors: McGarry Louise P. , Greene Charles H. , Wiebe Peter H. , Croll Donald A.
Published: October 2013

Blue whales, the largest animal on the planet, are frequently found in concentrations at the ocean surface in areas over thick sound-scattering layers of krill. In this study, the dive behavior of a blue whale was investigated in the context of zooplankton acoustic backscatter data concurrently collected in the Monterey Bay submarine canyon. The whale dive behavior revealed that the whale spent greater than 50 percent of its time in the region of the most intense backscatter, suggesting threshold foraging behavior. In order to describe the prey field within the canyon, additional day and night acoustic surveys with MOCNESS net tows in the canyon and along its perimeter were collected. Here, a three-dimensional characterization of the prey field is developed using the acoustic data. Further work will be undertaken to estimate the relative biomass of the zooplankton taxa generating the acoustic backscatter within and without the intense sound-scattering layer, and to model the acoustic backscatter that would be expected to be generated from the zooplankton specimens collected: the forward problem. [This work is supported by the ONR.]
Radiation force imparted on a kidney stone by a Doppler-mode diagnostic pulse
Authors: Sapozhnikov Oleg A. , Trusov Leonid A. , Gromov Alexander I. , Owen Neil R. , Bailey Michael R. , Crum Lawrence A.
Published: October 2013

Detection of kidney stones and estimation of their sizes is an important part of the lithotripsy treatment. Fluoroscopy is often used to target stones, but not every stone is radio-opaque and, in addition, fluoroscopy produces ionizing radiation. Acoustic waves offer an alternative way to visualize stones. The acoustic impedance of kidney stones typically differs significantly from that of surrounding tissue. A useful consequence of the impedance mismatch is the possibility to target stones with diagnostic mode ultrasound. Another consequence is that radiation force pushes the stone. Stone displacement may be responsible for the twinkling artifact that has been observed by several authors in color Doppler mode of ultrasound imaging. This effect can be used to detect not only renal and ureteral stones, but also calcifications in other organs (e.g., breast). In this paper we model the radiation force associated with the Doppler diagnostic pulse. The problem is divided into three parts: (1) acoustic scattering; it is solved in finite differences; (2) radiation force calculation; (3) stone velocity estimation supposing the stone sits in soft tissue. [Work supported by NIH DK43881, DK55674, NSBRI SMS00402, and RFBR.]
Shock-wave energy deflection due to the presence of bone
Authors: Matula Thomas , Tu Juan , Bailey Michael , Fagnan Kirsten , LeVeque Randy
Published: October 2013

The physical interaction of shock waves with musculoskeletal tissues is inherently different from other high-pressure acoustic therapies. Whereas high-intensity focused ultrasound and lithotripsy focus their energy in regions of soft tissue, musculoskeletal shock-wave therapy (SWT) involves focusing shock waves (SWs) near or at bones. The presence of bones will cause reflection, refraction, and diffraction of acoustic energy. In our analysis of cavitation generated during clinical SWT treatment, we noticed that the cavitation was occurring away from the SW focus. We confirmed this by performing an in-vitro experiment on a bone embedded in gel. We also quantified the deflection angle as a function position near a bone in water: A talus was manufactured using rapid prototyping. It was placed near the focus of an electrohydraulic SW device. To visualize the pressure field, a high-speed camera imaged the cavitation field generated around the focus. As the bone was moved closer to the focus, the cavitation field (and thus, the pressure field) deflected away from the bone. The deflection angle was measured as a function of relative distance between the bone and focus. Numerical simulations were performed to model the deflection of energy away from the bone.
A sensitive, broadband polyvinylidine difluoride (PVDF) hydrophone for accurate characterization of shock waves
Authors: Maxwell Adam D. , MacConaghy Brian E. , Sapozhnikov Oleg A. , Bailey Michael R.
Published: October 2013

Few hydrophones are capable of measuring high-intensity fields such as shock waves accurately. One of the more reliable is the fiber-optic probe hydrophone. However, this system is expensive and insensitive. We created a new PVDF hydrophone and compared it with a fiber-optic system. The hydrophone consisted of a 25-μm-thick PVDF membrane with a 0.5-mm active element and a preamplifier, which were each held in separate attached polycarbonate housings. The amplifier had adjustable gain and could account for membrane resonance to flatten the frequency response. A model of the frequency response for the system was developed, which agreed well with the measured response. Shock waves were measured in two Dornier HM-3 clones and an electromagnetic lithotripter. Measurements were also recorded using a 2-MHz focused piezoceramic source and a broadband PVDF source. Shock-wave measurements closely matched those recorded by the fiber-optic hydrophone and calculations made with a KZK-type model. Very little damage to the membrane was found after applying several thousand shock waves. This new membrane hydrophone is robust and sufficiently accurate to measure high-intensity fields, while greatly reducing cost, increasing sensitivity, and simplifying measurements of shock waves. [Work supported by NIH DK43881, DK55674, and NSBRI SMS00402.]
Calculation and measurement of acoustic scatter to assess fragmentation in shock wave lithotripsy
Authors: Owen Neil R. , Sapoznikov Oleg A. , Bailey Michael R. , Crum Lawrence A.
Published: October 2013

Shock wave lithotripsy (SWL) is currently conducted with little feedback on whether kidney stones are breaking. To determine if fragmentation could be assessed, acoustic scatter from intact and fractured stone models was calculated numerically and measured in vitro. Acoustic scatter from the stones, which were modeled with glass spheres, was calculated numerically using a linear elastic model, initialized with known elastic constants, and propagated from the stone model surface using the Helmholtz-Kirchhoff integral. Experimentally, shock waves were generated with a research lithotripter and scatter was measured with a broadband, spherically focused receiver. Calculated and measured results agreed well in the time domain. In frequency, power spectra were integrated to find energy and showed that scatter from the fractured stone model had higher energy in specific frequency bands that were related to the reverberation period. High-speed photography indicated that cavitation did not adversely affect the analysis of scatter. In this work it was possible to distinguish between the intact and fractured stone models. This method could be applied to stones that fragment gradually under the application of shock waves and potentially be used to estimate fragment size, and therefore the endpoint of therapy. [Work supported by NSBRI SMS00402 and NIH DK43881.]
Temperature dependence of acoustic properties of human tissues with a high-resolution ultrasound backscatter microscope
Authors: Park Jee Woo , Liu Jiehui , Kim Byoung Nam , Yoon Suk Wang
Published: October 2013

The B-mode in vitro images of human skin and ocular tissues are obtained using a high-resolution ultrasound backscatter microscope (UBM) at the frequencies of 40, 80, and 100 MHz. It shows that a high-resolution UBM can visualize more detailed superficial microstructures of skin and eye at higher frequencies. In order to improve high-frequency ultrasound images, we have investigated the acoustic properties, such as sound velocity, sound attenuation, and backscatter coefficient, of human tissues with this UBM system over the frequency range from 25 to 110 MHz. Their acoustic properties are also investigated as a function of temperature in the range from 20°C to 65°C, which may provide bases for ultrasound image monitoring of thermal therapy. [Work supported by Strategic National R&D Program of Ministry of Commerce, Industry and Energy (MOCIE), Republic of Korea.]
Calibration for biological acoustic impedance microscope
Authors: Hozumi Naohiro , Terauchi Satoshi , Kimura Ayumi , Nagao Masayuki , Yoshida Sachiko , Kobayashi Kazuto , Saijo Yoshifumi
Published: October 2013

The presentation deals with the calibration for a biological acoustic impedance microscope. A block of tissue was placed on a plastic substrate, and an acoustic pulse focused on the interface was transmitted from the rear side of the substrate. The reflection was received by the same transducer and interpreted into local acoustic impedance. An acoustic impedance image was obtained by mechanically scanning the transducer. A reference material was simultaneously observed in order to perform calibration. A water droplet was employed as a reference material, however, it often entered into the interface between the substrate and tissue, leading to the reduction of the image quality. Therefore, several kinds of compounds were investigated. Silicone rubber was relatively homogeneous and stable in acoustic impedance, after a certain period of curing time. However, its dispersion with the scale of focal spot size was as large as 0.02 Ns/cm3, suggesting that a sufficient number of points should be measured and averaged in order to obtain a precise reference signal. Finally, change in local acoustic impedance of cerebella tissue of a rat as a function of postnatal days was quantitatively assessed for each independent layer like molecular layer, granular layer, and white matter.
Correlation between the degree of hemolysis and acoustic impedance, speed of sound, and attenuation in flowing whole blood
Authors: White Adam , Coussios Constantin-C.
Published: October 2013

The effect of increasing levels of mechanical hemolysis on the propagation of 15-MHz ultrasound in flowing whole blood at 37°C was investigated. An experimental setup was developed, which enabled the continuous measurement of attenuation, speed of sound, and acoustic impedance in porcine whole blood under conditions of laminar flow and mean shear rates well above the threshold for red cell aggregation. Starting with an initial hematocrit of 35%, an increasing volume fraction of the blood in the flow loop was hemolyzed by exposure to very high shear stresses. The attenuation coefficient at 15 MHz was found to vary between 1 dB/cm for 0% hemolysis (no red cell damage) to 5 dB/cm for 75% hemolysis, remaining approximately constant for higher hemolysis levels. Speed of sound decreases from 1561 m/s for healthy blood to 1545 m/s for 80% hemolysis. Finally, acoustic impedance was also found to vary from a minimum of 1575 Kg/m2 to 1589 Kg/m2 between 15% and 90% hemolysis. These results show great promise towards solving the inverse problem, namely developing a technique capable of deducing the degree of hemolysis noninvasively and in real time based on measured changes in ultrasound parameters.
Erythrocyte aggregability from human, horse, and rat blood by ultrasound backscattering measurements
Authors: Nam Kwon-Ho , Paeng Dong-Guk , Bok Tae-Hoon , Choi Min Joo
Published: October 2013

A pulse-echo system was used in a cylindrical chamber with a stirring magnet and a 5-MHz focused transducer for studying erythrocyte aggregation from human, horse, and rat blood. The highest backscattering power was measured from horse blood and followed by human and rat blood both at stasis and under shear forces. In human and horse blood, the backscattered power (BP) was decreased with stirring speed and saturated within 1 min. The BP was increased to 20 dB when blood flow was stopped. Since the aggregation of rat erythrocytes in autologous plasma is very low and barely detectable by the ultrasound BP, rat plasma was replaced by phosphate buffered saline containing polyvinylpyrrolidone 360 in order to enhance the aggregation. In conclusion, this simple in vitro ultrasound measurement system requires a small amount of blood, which may provide an alternative method to investigate the mechanisms and physiological roles of erythrocyte aggregation. Furthermore, the rat erythrocytes in polymer solution may be useful for an automatic measurement system to examine the bioactive materials that affect aggregation in preclinical studies.
Measuring micro liquid volume by acoustic resonant technique
Authors: Wakabayashi Makoto , Koyama Daisuke , Nakamura Kentaro , Ueha Sadayuki
Published: October 2013

A method to measure micro liquid volume less than 300 ln with the accuracy of 0.1% is highly needed in biogenetic and biochemical industries. The authors propose a novel method to estimate micro liquid volume in a small well using acoustic resonance. In our experiments, liquid is in a container 6.5 mm in inner diameter and 9 mm in height, and the sound pressure near the well is measured by sweeping the illuminating sound field from 6 to 11 kHz. According to the relationship between the resonance frequency and the volume, we can successfully estimate the small volume with the accuracy of 0.1% and an excellent repeatability. For simultaneous multipoint measurements, we experimentally investigate the effect of adjacent wells on resonant frequency of the target well. It is revealed that the resonance frequency shift due to the mutual coupling between the adjacent wells is negligible if the well interval is less than 5 mm.
Removal of thin hard coating on glass substrate by collision of nanometer-sized particles accelerated in high-intensity ultrasonic field
Authors: Kudo Naoya , Adachi Kazunari
Published: October 2013

The aim of this study is to establish a fundamental recycling technology for optical lenses. In industry, a common conventional technique for cleaning the surface of a small object such as an optical lens is through the use of ultrasonic cavitation. However, the intensity of shock waves caused by the cavitation is difficult to control. The authors have considered that the substances that adhere to lens surfaces, such as hard optical coatings and stains, are removable using collisions, against the lens surface, of many tiny particles that are accelerated by a high-intensity ultrasonic field. Some physical parameters that dominate the removal effect have been changed systematically to illustrate the surface-refreshing process for lenses in the experiments. The authors worked to experimentally clarify the particle collision effect on the removal. In addition, the acoustic field was analyzed using finite-element method. The authors have also attempted to elucidate the principle of the removal technique through comparison of experimental results with those obtained through numerical simulation. A precise elucidation, however, remains as an important problem to be solved.
Nondestructive inspection system for corrosion detection in fuel tank liners
Authors: Doane John W. , Gray Michael D. , Caspall Jayme J.
Published: October 2013

An ultrasonic, nondestructive inspection system for the early detection of corrosion in fuel tank aluminum liners was developed and tested. A Labview-controlled scanner, which rode on the tank’s resident rib braces, housed a 10-MHz transducer and a miniature video camera. The bi-directional (axial, azimuthal) scan resolution was controlled by adjusting the surface standoff distance of the focused transducer to produce variable-area interrogation sites. The phenomenon of increased backscatter from corrosion-roughened surfaces was exploited to detect the presence of corrosion in its early stages. The transducer acted as both transmitter and receiver, capturing the echoes from the subject surface while the video camera captured an image of the surface under acoustic inspection. The acoustic and visual data were overlayed to form a composite image of the entire inspection surface. The system was field-tested using two tanks pulled from active duty at the Marine Corps maintenance facility in Cherry Point, NC. [Work supported by JCAA.]
Evaluation of the static stress exerted on the clamping bolt in the structure of a bolt-clamped Langevin-type transducer
Authors: Takahashi Toru , Adachi Kazunari
Published: October 2013

Bolt-clamped Langevin-type transducers (BLTs) must possess various characteristics depending on the field in which they are used. It has already been clarified by the authors that prestress or bearing stress imposed on piezoelectric elements in a transducer should be sufficiently large to compensate for their low tensile strength. For this study, we measured the strain on the clamping bolt surface using strain gauges pasted on it to evaluate the static prestress that changes with the turning angle of the metal block in clamping. We calculated the strain for some BLTs of identical shape using the finite-element method (FEM) and measured it to confirm the validity of the prestress calculation that was achieved previously by the authors. Unfortunately, a large difference in the strain between the calculated and measured results was observed. We cited three possible reasons for that huge discrepancy. Among them, plastic deformation of the screw thread might most influence the result. As long as the design problem of BLTs pertaining to the prestress remains unresolved, we cannot take full advantage of the excellent electromechanical transduction efficiency of BLTs for high-power ultrasonic applications.
Multilayered high-performance transducer using polyurea thin film
Authors: Nakazawa Marie , Tabaru Masaya , Koyama Daisuke , Nakamura Kentaro , Ueha Sadayuki , Maezawa Akihiro
Published: October 2013

Polyurea thin film exhibits useful characteristics as a high-frequency ultrasonic transducer such as a low acoustic impedance of 70% of that of PVDF, considerably high piezoelectric constants compatible with conventional piezoelectric polymers, and a higher Curie temperature. A polyurea thin film transducer working at over 100 MHz can be made on any surfaces through vapor deposition polymerization with a high controllability of thickness. To enhance the transducer performance, a multilayered configuration is studied in this study. A special twin-vacuum-chamber is used for laminating the polyurea layers and the aluminum electrodes alternately. We fabricate two- and three-layered transducers with 1.5-μm polyurea thin films as well as single-layer transducers. To evaluate the transducer performances, we measure the capacitances, the electrical admittances, the coupling factors, and the Q values. The pulse/echo measurements are also conducted to determine the transmission and receiving characteristics of the transducers using a glass plate as a reflector. The results of the pulse/echo experiments show that the received voltage amplitude of the multilayered transducer is higher than that of the single-layer transducer.
Analysis of fluid-borne coupling in transducer arrays
Authors: Kotsidou Kassiani , Thompson Charles
Published: October 2013

In this work, we will analyze fluid-borne coupling between adjacent elements of a transducer array. In the case of a transducer having low inertia mass, such coupling can result in a reduction in the radiation efficiency and the directional fidelity of the array. The coupling factor and the mutual radiation impedance have been investigated by Lord Rayleigh (1903), Wolff and Malter (1929), and R. I. Pritchard (1960) for the case of an array comprised of ideal piston radiators. These results will be used as a starting point for our work. The effect of the inertia impedance of the transducer and the control of the special distribution of the radiated field is considered.
Development of educational software that supports study of sound environment for children
Authors: Sakai Hiroyuki , Shirakawa Tadashi , Tanaka Munetaka
Published: October 2013

A sound map, on which observed sounds are drawn as visual symbols, is well known as one of the nature games. Sound educational software, cultivating children’s ecological view through their daily experiences focusing on sounds, was developed by using the sound map concept. Children record observed sounds through a sound-walk in outdoors into PC, and learn the sound environment through their collaborative work including classification, analysis, and group discussions in a workshop or a class. In a traditional approach on the field of educational technology, a lot of teaching materials introducing novel ICTs (information and communication technologies) are developed, but it is rather important to support usefulness for users (children and teachers), promote motivations for their learning, and support the smooth learning progressive process. In this presentation, the development concept of the software for the sound environment study based on socio-cultural approach is discussed, while an actual use example of this software is demonstrated.
Stimulating children’s interest in acoustics using models and toys
Authors: Prasad M. G.
Published: October 2013

Sound is an important means for sensory perception. Children, being naturally curious and sensitive, respond very well to sound. Simple acoustical toys attract their curiosity and attention. The use of simple sound- or music-producing tools draws their attention and then they ask questions. In answering their questions simple principles of acoustics and scientific reasoning can be taught to them. Simple principles such as tone change due to change of volume in a resonator, the role of length in the sound produced by a tube, the role of damping in cutting down vibration and sound, etc. can be taught to the children. Also, the description of noise being unwanted sound can be demonstrated using simple mechanical models with comparison to desirable sound as music through instruments such as the flute. A model of the human ear can be used to describe the way the sound is perceived. The use of models and encouraging children to ask questions will further enhance their curiosity. The author will share his experiences gained through making presentations for elementary school children.
Re-equipping the University of Sydney’s acoustics laboratory for teaching after a fire
Authors: Stewart Ken , Cabrera Densil
Published: October 2013

For some decades, the University of Sydney has taught and conducted research in architectural and audio acoustics from the Faculty of Architecture’s acoustics laboratory. In October 2005, a fire in the anechoic room destroyed the laboratory mainly through heat and smoke damage. Recovery has involved a reconsideration of the systems used for teaching and research, and this presentation outlines our approach to this. One consideration is that measurement systems should be relatively self-contained, so that setup time for measurements is minimized, and several setups can be used simultaneously for hands-on teaching. New equipment tends to be computer based, which has the advantages of much greater measurement power, automation, recording, and interfacing, but can be less intuitive for students to understand than individual analog components. This presentation compares the preexisting and renovated laboratory, especially in terms of teaching strategies in audio and acoustics using technical equipment. We present examples of previous and envisaged student projects to illustrate how such infrastructure can support learning.
Vibro-acoustic measurement of several biwas
Authors: Taguti Tomoyasu , Tohnai Kakuryo
Published: October 2013

The biwa is a family of Japanese lutes that have been played for more than 1000 years. This paper reports some measurements on the vibro-acoustic characteristics of several biwas of different types. The main concern is the similarity and difference of the fukuju-to-table transfer mobilities among the individual biwas. Here, the fukuju is a kind of bridge whose shape and way of installation differ distictively from those common to the majority of other lute families found in many countries in the past as well as in the present time. The measurement revealed that in most cases the fukujus have two major vibration modes, to be labeled the ‘‘twist’’ and ‘‘flap’’ modes, with the corresponding resonance frequencies in the regions of about 0.9 to 1.2 kHz and of 1.4 to 1.6 kHz, respectively, though the exact figures depend on the physical size and shape. Their resonance property takes an important roll to determine the fukuju-to-table transfer mobility as the coupled vibroacoustic system with the table. The fukuju-to-table mobilities were compared with the spectra of the corresponding plucked sounds.
Development of a carbon-fiber-reinforced composite for guitar soundboards: Investigation of bracing effect by experiment and simulation
Authors: Okuda Akira , Ono Teruaki
Published: October 2013

A carbon-fiber-reinforced polyurethane foam composite whose physical and acoustic properties closely resemble those of wood for stringed-instrument soundboards was developed. A guitar with such a composite-made soundboard produced an almost identical tone to that produced with a wooden soundboard. The procurement of wood for soundboards, however, has not yet become very difficult. To accelerate the production and use of guitars with composite soundboards, it is necessary to create an attractive guitar that has characteristic and unique tones that cannot be realized on a wooden soundboard, making use of composite characteristics of design freedom. Wooden top boards, soundboards, have bracing that has traditionally and experientially been glued; however, the effects of bracing have never been clarified. In this study, the bracing effect on the frequency response and vibration mode in a guitar top board was investigated using experimentation and simulation. From the results obtained, a composite-made soundboard with no bracing, which produces more harmonics than a wooden one with bracing, was simulated as an example.
Inharmonic sounds of bowed strings in Western music and Beijing opera
Authors: Tsai Chen-Gia
Published: October 2013

Due to the nonlinear bow-string interaction, inharmonic sounds can be produced by bowed strings. Such sounds are characterized by subharmonics, sidebands, and noises. Bow location, bow speed, and bow pressure on the string have been found critical to producing inharmonic sounds on the violin or the cello. In the accompaniment music of Beijing opera singing, inharmonic sounds produced by the major bowed-string instrument (the jinghu) are sometimes called ‘‘blossoming tones.’’ They are played with a special touch technique of the left hand, and a chaotic behavior of string vibration arises from a nonlinear boundary condition with unilateral constraints. The spectra of blossoming tones can be viewed as high-pass noises, with the cutoff frequency of about 1.6 kHz. Blossoming tones are sophisticatedly used for emotional expressions in Beijing opera. Their harsh quality recalls some pathological human voices.
Realism assessment of sonic boom simulators
Authors: Sullivan Brenda M. , Davies Patricia , Hodgdon Kathleen K. , Salamone Joseph , Pilon Anthony
Published: October 2013

The perceived realism of booms reproduced in three simulators, at NASA, Lockheed Martin, and Gulfstream Aerospace, was studied. The NASA and Lockheed facilities are loudspeaker-driven, airtight concrete structures that enable reproduction of the entire spectrum, including the very lowest frequencies. The Gulfstream facility is enclosed within a trailer and consists of a folded horn as well as loudspeakers. This creates the sonic boom waveform as a traveling wave but is unable to reproduce the lowest frequencies. In the tests, subjects experienced in listening critically to real sonic booms heard reproductions in the simulators of sonic booms recorded outdoors. Tests comparing the NASA/Gulfstream simulators and the Lockheed/Gulfstream simulators used the same outdoor sonic boom waveforms, though each simulator uses its own preprocessing to equalize the waveforms for presentation. The tests showed that the presence of ground reflections, very low frequencies, or recording hiss were not factors in realism ratings. However, the inclusion of some of the postboom noise heard after the boom itself was found to be extremely important for a realistic boom simulation.
Human response to low-intensity sonic booms heard indoors and outdoors
Authors: Sullivan Brenda M. , Klos Jacob , Buehrle Ralph D. , McCurdy David A. , Haering Edward A.
Published: October 2013

A house on Edwards Air Force Base, CA, was exposed to low-intensity N-wave sonic booms during a 3-week test period in June 2006. The house was instrumented to measure the booms both inside and out. F-18 aircraft were flown to achieve a variety of boom overpressures from approximately 0.01 to 0.06 psf. During 4 test days, 77 test subjects heard the booms while seated inside and outside the house. Using the Magnitude Estimation methodology and artificial reference sounds, the subjects rated the annoyance of the booms. Since the same subjects heard similar booms both inside and outside the house, comparative ratings of indoor and outdoor annoyance were obtained. Preliminary results from this test will be presented.
Building structural acoustic response to aircraft sonic booms
Authors: Buehrle Ralph D. , Klos Jacob , Sullivan Brenda M. , Haering Edward A.
Published: October 2013

As part of the NASA Low Boom/No Boom flight test project, a series of low-amplitude sonic-boom tests was completed over a 3-week period in June of 2006. This series of flight tests was designed to evaluate indoor/outdoor human subjective response, structural acoustic building response, and the effects of atmospheric turbulence for low-amplitude sonic booms characterized by overpressures in the nominal range of 0.1 to 0.6 pounds per square foot (psf). Low-amplitude sonic booms were generated by F-18 aircraft using dive trajectories to produce a range of overpressures at the Edwards Air Force Base housing area. In addition, straight and level supersonic flights were used to generate normal level (nominally 1.4 psf) sonic-boom overpressures at the housing area. This report will describe the structural acoustic building response measurements obtained during this flight test project. A single-family ranch-style home was instrumented with nearly 300 microphone and accelerometer sensors to determine the incident pressure and the building’s structural acoustic response. Data were acquired for over 100 sonic-boom events. The test setup will be described and analysis of the measurements will be presented.
Modeling and measurements of nonlinear spherically divergent N waves in air
Authors: Khokhlova Vera A. , Averiyanov Mikhail V. , Yuldashev Petr V. , Ollivier Sebastien , Blanc-Benon Philippe
Published: October 2013

Propagation of nonlinear N pulses in relaxing medium was studied experimentally and numerically. An electric spark source was used in laboratory-scale experiments in ambient air to obtain spherically divergent shock pulses of 30-s duration and 1000-Pa peak pressure at 15-cm distance from the source. Pressure waveforms were measured by the broadband 1/8-in. microphone at the distances varying from 15 cm to 2 m from the spark source. A numerical solution was obtained for an initial analytic N waveform at the same distances based on the modified Burger’s equation for nonlinear spherical waves in dissipative medium with relaxation. The duration of the initial N wave was defined by matching the zero values of the corresponding analytic measured spectra; the amplitude was obtained by matching the experimental and theoretical nonlinear propagation curves for the N-wave duration. The results of modeling were found to be in good agreement with the experimental data. A frequency response of the microphone was obtained at various distances as a ratio between the measured and modeled spectra and showed a good reproducibility. The relative effects of relaxation, nonlinearity, and microphone filtering on the N-waveform parameters are discussed. [Work is supported by RFBR and INTAS grants.]
An attempt to measure the hearing thresholds for high-frequency sounds by using the auditory brain-stem response
Authors: Hosokawa Kazumasa , Ashihara Kaoru , Kiryu Shogo
Published: October 2013

Recently, devices using high-power ultrasounds are increasing. However, influences of high level ultrasounds on human are not fully understood. Psychophysical studies show that the hearing thresholds exceed 80 dB SPL at a frequency above 20 kHz. It is reported that high frequency sounds above 20 kHz affect activities in the human nervous system. In order to examine whether the peripheral auditory system can be activated by high-frequency sounds, an attempt is made to measure the auditory brainstem response (ABR) for the frequency range between 4 and 20 kHz. In preliminary experiments, the ABR was measured for a tone pip with the center frequency of 14 kHz. However, the ABR was not clearly observed above 16 kHz. The thresholds determined by the ABR were approximately 40 dB larger than the psychophysical thresholds. The ABR was evoked by low-frequency components of the tone pip at the high presentation levels.
Distortion product otoacoustic emission fine structure as an early hearing loss predictor
Authors: Reuter Karen , Hammersho/i Dorte
Published: October 2013

Otoacoustic emissions (OAEs) are a promising method to monitor early noise-induced hearing losses. When distortion product otoacoustic emissions (DPOAEs) are obtained with a high-frequency resolution, a ripple structure across frequency can be seen, called DPOAE fine structure. In this study DPOAE fine structures are obtained from 74 normal-hearing humans using primary levels of L1/L2=65/45 dB. The subjects belong to groups with different ages and exposure histories. A classification algorithm is developed, which quantifies the fine structure by the parameter’s ripple place, ripple width, ripple height, and ripple prevalence. Temporary changes of the DPOAE fine structure are analyzed by measuring DPOAE both before and after exposing some of the subjects to an intense sound. The characteristic patterns of fine structure can be found in the DPOAE of all subjects, though they are individual and vary from subject to subject within groups. The results do not indicate that the DPOAE fine structure alters with the state of hearing, as it is suggested in the literature. The data analysis is still in process at this stage.