bluuebunny/crossref_metadata_2025 huggingface dataset:
Pool Boiling and Flow Boiling CHF Enhancement at Atmospheric Pressure Using Magnetic Nanofluid
Authors: Lee Taeseung , Lee Jong Hyuk , Jeong Yong Hoon
Published: October 2013

In this study, we suggest a new working fluid: magnetic nanofluid, or magnetite-water nanofluid, which is a colloidal suspension of magnetite nanoparticles in the pure water. By using the nanofluid, we can expect the critical heat flux (CHF) enhancement, and also for the magnetic nanofluid. Since the magnetite nanoparticles can be controlled by an external magnetic field, the magnetic nanofluid is regarded as a controllable nanofluid, and thus, we can expect the advantages of magnetic nanofluid: 1) the nanoparticle suspension in nanofluid can be maintained by applying the alternating magnetic field, 2) the nanofluid concentration can be localized by applying the magnetic field for a region of interest and 3) the magnetite nanoparticles can be removed from magnetic nanofluid easily.

In this study, we focused on the CHF characteristics of magnetic nanofluid in both pool boiling and flow boiling. The first part is for the pool boiling CHF of magnetic nanofluid. At atmospheric pressure, saturated pool boiling CHF experiments were conducted using Ni-Cr wire for magnetic nanofluid and the other nanofluids. Among the various nanofluids, magnetic nanofluid has the highest value of pool boiling CHF, and the enhancement ratio (with respect to the pure water) ranges from 170 to 240 percent. To elucidate the mechanism underlying the pool boiling CHF enhancement, three approaches were introduced: 1) scanning electron microscope (SEM) images were obtained to explain the pool boiling CHF enhancement mechanism due to the deposited nanoparticles, which is related to the surface wettability of the heat transfer surface, 2) ultra-high speed movie were taken and analyzed to observe the bubble dynamics at the heat transfer surface and 3) the strength of electricity-induced magnetic field neat the heat transfer surface were calculated to examine the effect of magnetic field on the pool boiling CHF.

The second part is for the flow boiling CHF of magnetic nanofluid. A series of flow boiling CHF experiments were performed at atmospheric pressure and low mass flux conditions. Based on the experimental data, we conclude that the use of magnetic nanofluid improves the flow boiling CHF characteristics: the flow boiling CHF enhanced for the magnetic nanofluid. This is mainly due to the deposition of magnetite nanoparticles on the heat transfer surface, which results in the improvement of wettability and re-wetting characteristics. And we need enough time to ensure the nanoparticle deposition and the flow boiling CHF enhancement, when a nanofluid is used as a working fluid.
Thermal-Hydraulic Analysis of Concept Design of Spallation Target in Chinese Accelerator Driven Subcritical System
Authors: Zhou Zhiwei , Zhang Yaoli , Xiao Sicong , Yang Yongwei
Published: October 2013

A concept design of spallation target in Chinese Accelerator Driven Subcritical System (ADS) was proposed in this paper. Spallation target is located in the center of an ADS, which produces neutron source for nuclear transmutation. The thermal-hydraulic demands for spallation target were proposed, and Lead-Bismuth Eutectic (LBE) was chosen as the spallation target and the coolant for the ADS. The deposition heat in the spallation target was calculated by MCNPX code, and the thermal-hydraulic behavior in the spallation target zone was calculated by CFD code FLUENT. The target can fulfill the design tasks under current design parameters. Different design parameters as well as different window shapes were studied to find their impacts to the temperature distribution and velocity distribution, and a proper design was proposed for future ADS with higher input energy.
Beryllium and Beryllium Oxide by XPS
Authors: Mallinson Christopher F. , Castle James E.
Published: October 2013

As received beryllium and beryllium oxide, purchased from Goodfellow, were analysed by x-ray photoelectron spectroscopy. Survey spectra, high resolution spectra of elemental peaks and beryllium Auger transitions were collected and are presented. The binding energy of metallic beryllium 1s peak and the beryllium oxide 1s peak were found to be 110.5 and 113.4 eV respectively. The kinetic energy of the main metal and oxide KVV Auger transitions were found to be 103.5 and 95.5 eV respectively.
Binaural simulation in an enclosure using the phased beam tracing
Authors: Jeong Cheol-Ho , Ih Jeong-Guon
Published: October 2013

Binaural simulation in an enclosed space is important in the subjective evaluation of the enclosure acoustics in the design or refinement stage. A time domain scheme using the geometrical acoustics technique has been usually used in the binaural processing. However, one can calculate a pressure impulse response by using the phased beam-tracing method, which incorporates the phase information in the beam tracing process. Such phased method employs reflection coefficient and wave number, whereas the conventional method uses absorption coefficient and air attenuation factor. Impulse response can be obtained by the inverse Fourier transformation of the frequency domain result. This feature facilitates the binaural simulation because the convolution with the HRTF can be accomplished by a simple multiplication in frequency domain. Convolutions were conducted for all reflections one by one, and the convolved transfer functions were summed into one transfer function. Consequently binaural room impulse responses at receivers’ ear positions can be simulated. The measured binaural room impulse responses in the conference room were compared with the predicted results for octave bands of 125 Hz to 4 kHz. A good agreement with measurement was found, especially in the early part of impulse responses. [Work supported by BK21.]
Acoustic evaluation of worship spaces in the city of Curitiba, Brazil
Authors: Pulsides Cristiane , de Sant’Ana David Q. , Ansay Samuel , Zannin Paulo Henrique T. , Damico Suzana
Published: October 2013

This article searches acoustic parameters in religious buildings located in the city of Curitiba intending to study its behavior in this kind of facilities. The temples were analyzed according to type of ceremony, architectonic style, and construction date. The research was made through the impulsive response integration method for three energetic parameters: (1) reverberation time (RT); (2) clarity (C80); and (3) definition (D50) according recommendations of the ISO/3382:1997 Standard. Performed in between were six and eight impulsive responses in each room using sweep signals and omnidirectional microphones. The results were than compared with referential values already existing [W. Fasold and E. Veres, Schallschutz + Raumakustik in der Praxis, 136 (1998)] for acoustic characterizations. It is possible to observe in the measurements the direct connection between reverberation time and the parameters clarity or definition. Moreover, it is possible also to observe the influence of the geometric ratios and architectural elements of the rooms, getting itself for equivalent volumes and rays of removal of the source, different levels of definition.
Seasonal ambient noise levels and impacts on communication in the North Atlantic right whale
Authors: Parks Susan E. , Clark Christopher W. , Cortopassi Kathryn A. , Ponirakis Dimitri
Published: October 2013

The North Atlantic right whale is a highly endangered species of baleen whale. Acoustic communication plays an important role in the social behavior of these whales. Right whales are found in coastal waters along the east coast of the United States, an area characterized by high levels of human activity. Most of these activities generate noise that is propagated into the coastal marine environment. The goals of this project are to characterize the noise, both natural and anthropogenic, in right whale habitat areas to determine what levels of noise the whales are regularly exposed to, and whether the acoustic behavior of right whales changes in response to increased noise. Continuous recordings were made from autonomous bottom-mounted recorders in three major habitat areas in 2004 and 2005; Cape Cod Bay (December–May), Great South Channel (May), and the Bay of Fundy, Canada (August) to passively detect right whales by recording their vocalizations. Here, we describe the ambient noise levels in these recordings to describe the daily acoustic environment of right whales, how noise varied over diel, weekly, and seasonal time scales, and whether noise levels correlated with any observed changes in acoustic behavior of the whales.
Blue whale calling in Australian waters
Authors: McCauley Robert D. , Salgado Kent Chandra P. , Burton Christopher L.K. , Jenner Curt
Published: October 2013

Calling from the Antarctic true blue whale (Balaenoptera musculus intermedia) and the tropical subspecies (brevicauda, or pygmy blue) have been recorded across southern Australia with the pygmy blue calls also recorded along the Western Australian (WA) coast. The subspecies have a believed common downsweep and markedly different longer, tonal calls. The frequency of most energy in the tonal calls is offset between the subspecies suggesting sound-space partitioning. The pygmy blue three-part tonal call is typically 120 s long repeated every 200 s, has several variants, and includes a complex two-source component. The nature of the pygmy blue call allows counts of instantaneous calling individuals, giving relative abundance. These estimates in the Perth Canyon, a localized seasonal feeding area, show patterns in usage of space and through time within and between seasons, such as the sudden departure of animals at a season end, which varies by approximately 2 weeks between years. Sea noise records along the WA coast indicate south-traveling animals arrive midway along the coast in October to November, animals fan out across southern Australian over December through May, then move north in the Austral winter. We have begun converting abundance estimates from relative to absolute for pygmy blue calling rates.
Acoustical monitoring of finback whale movements on the New Jersey Shelf
Authors: Turgut Altan , Lefler Christopher
Published: October 2013

Acoustical monitoring of finback whales is performed by using a data set collected over a 3-week period in December of 2003 on the New Jersey Shelf. One-second-duration 20-Hz signals of finback whales were recorded on three vertical line arrays (VLAs) and a bottomed horizontal line array (HLA.). One-second-duration pulses are separated by about 10 s and there is an approximately 2-min-long silent period between 10- to 18-min-long pulse trains. A 30- to 60-min silent period after 5 to 10 pulse trains is also common. Modal analysis of individual pulses indicated that most signals contained two acoustic modes. Arrival-time and group-speed differences of these modes are used for remote acoustic ranging. These modal characteristics are also exploited in a broadband matched-field algorithm for depth discrimination. Bearing estimation of individual whales is obtained by performing horizontal beamforming on the HLA data. Range estimation results are verified by time-of-flight triangulation using single hydrophone data from each VLA location. Acoustic monitoring results indicated that most finback whales traveled near the shelf break front where food might be abundant. Relations between silent periods and acoustic range/depth monitoring results are also investigated. [This work was supported by the ONR.]
Analysis of melon-headed whale aggregation in Hanalei Bay, July 2004
Authors: Fromm David M. , Mobley Joseph R. , Martin Stephen W. , Nachtigall Paul E.
Published: October 2013

On 3 July 2004, an aggregation of ca. 150–200 melon-headed whales (Peponocephala electra) appeared in the shallow waters of Hanalei Bay, Kauai and congregated there for over 27 h. Preceding the whales’ appearance and partially coincident with their time in the Bay, midrange (3.5–5 kHz) tactical sonars were intermittently deployed during the Rim of the Pacific 2004 (RIMPAC) joint military exercises being conducted in waters near Kauai by the U.S., Japan, and Australia Navies. An NOAA report (Southall et al., 2006) attributed the active sonar usage as a plausible, if not likely, contributing factor. A detailed timeline and reconstruction of the RIMPAC activities is presented showing the worst-case estimates of the sonar sound levels in the waters surrounding Kauai. A re-examination of available evidence combined with a new report of a simultaneous and similar aggregation in Sasanhaya Bay, Rota, Commonwealth of the Northern Mariana Islands, brings the plausibility conclusion into question. [This work was sponsored by multiple sources. D. Fromm and S. Martin conducted acoustic analyses with funds provided by the U.S. Pacific Fleet. J. Mobley received funding from the U.S. Geological Survey. P. Nachtigall is sponsored by the Office of Naval Research for marine mammal audiometric studies.]
Midfrequency sound propagation in beaked whale environments
Authors: Wezensky Eryn M. , Stottlemyer Thomas R. , Mitchell Glenn H. , MacLeod Colin D.
Published: October 2013

Recent mass strandings of beaked whales (Ziphiidae, Cetacea) coinciding with the use of midfrequency range (1–10 kHz) active sonar have caused speculation about the potentially adverse effects of these sound sources. Particular questions of the research and regulatory communities concern whether beaked whale sensitivity to midfrequency sound exposure is influenced by oceanographic characteristics present at the time of the mass stranding events. This study investigated the interaction between beaked whale habitat characteristics and the nature of a midfrequency signal by analyzing the oceanographic factors affecting underwater acoustic propagation. Three types of model sites were selected from five specific geographical locations where beaked whales have been regularly recorded or where a mass stranding event has been reported. A ray-trace acoustic propagation model was used to generate transmission loss for a 3-kHz signal over a representative 60-km transect at each locality. Model outputs visually demonstrated how the combination of site/event-specific oceanographic characteristics affects the sound propagation of a moving source. A parametric sensitivity comparison and statistical analysis were conducted to identify influential factors between environmental parameters, source depth, and the resulting transmission loss. Major findings of this study as well as future research direction are discussed. [Research supported by NAVSEA.]
Examination and evaluation of the effects of fast rise-time signals on aquatic animals
Authors: Stocker Michael
Published: October 2013

Increasingly human enterprise is subjecting the ocean environment to acoustic signals to which marine animals are not biologically adapted. This is evidenced by a marked rise in marine mammal strandings, as well as hearing and other physiological damage to fish and other marine organisms as a result of, or coincident to, human-generated noise events. Determining phonotoxic thresholds of marine organisms is complicated by the fact that various marine animals are adapted to sense either pressure gradient or particle motion acoustic energy, or some combination or gradient between the two. This has been addressed to some degree by exposure metrics that consider either net or accumulated acoustical flux densities from various noise sources. This paper examines the role and effects of signal rise time both in terms of physiological impulse response of the exposed organisms, as well as broadband saturation flux densities of fast rise-time signals on animal sense organs. Case studies from the literature will be presented to demonstrate the effects of fast rise time signals on fish. Acoustical signals with high crest factors and fast rise-time components will be compared to signals with dominantly sinusoidal components to illustrate the perceptual effects of these signals on human hearing.
Using vocalizations of Antarctic seals to determine pupping habitats
Authors: Rogers T. L. , Hogg C. J. , Ciaglia M. B. , Cato D. H.
Published: October 2013

The Ross and Leopard seal use the floes of the Antarctic pack ice to whelp and raise their pups, But both species are rarely seen in summer throughout the pack ice. We now realize that this is because they are under the water ‘‘calling’’ during the austral summer as part of their breeding display, and so their presence is underestimated in traditional visual surveys. The period of ‘‘calling’’ overlaps with the time that females give birth, so their vocalizations can be used to determine seal distributions during this time. Acoustic recordings were made using sonobuoys deployed during ship based surveys in the pack ice and analyzed to determine the seal distributions. This was used to predict habitat preference of seals by relating their distributions to remotely sensed indices: ice cover, ice floe type, ice thickness, distance to ice edge, distance to shelf break, distance to land, sea surface temperature, and chlorophyll a.
Nonintrusive acoustic identification of hermit thrush (Catharus guttatus) individuals
Authors: Jones Dennis F.
Published: October 2013

From mid-April well into the summer, the secretive hermit thrush (Catharus guttatus) can be heard singing throughout the woodlands of Nova Scotia. Its song is distinctive, beginning with a clear introductory note followed by a flurry of flutelike body notes, often cascading and reverberant in character. Despite this fine display of avian virtuosity, few studies have been reported that probe the differences between the calls, songs, and repertoires of individuals. From April 2003 to May 2006, over 3000 songs from several birds were recorded using digital video cameras at study sites in and around the city of Halifax, Nova Scotia. The only birds recorded were those in close proximity to roads and trails. None of the birds were marked, banded, or deliberately disturbed in any way. Although the study birds remained hidden from view most of the time, in the few instances where the birds perched in the open, their behaviors while singing were captured on videotape. All of the birds were readily distinguishable from each other as no two individuals had a single song in common. The most significant finding was that individuals could be reidentified acoustically after 1 week, 3 months, and 1 year had elapsed.
Present and future of elasticity imaging technology
Authors: Shiina Tsuyoshi , Ueno Ei
Published: October 2013

Elastic properties of tissues are expected to provide us novel diagnostic information since they are based on tissue characteristics and sensitively reflect its pathological state. So far, various techniques for tissue elasticity imaging have been proposed. However, it was not so easy to satisfy real-time operation and freehand manipulation of probe, which was required for practical equipment. To satisfy these conditions, we developed the combined autocorrelation method (CAM) and recently manufactured a commercial ultrasound scanner, for real-time tissue elasticity imaging by implementing the CAM algorithm, By slightly compressing or relaxing the body through freehand operation, the strain images are obtained with real-time and superimposed on B-mode images with a translucent color scale. In addition, we proposed elasticity scores of malignancy by categorizing patterns of elasticity images of breast tumors into five classes from malignant to benign. As a result of diagnosis based on the elasticity score, it was revealed that even nonexperts could attain precise diagnosis of breast cancer based on elasticity score as well as experts since the criterion on elasticity score is much simpler than conventional B-mode images. Finally, some prospects for the next stages of elasticity imaging technology well be surveyed.
Tissue pulsatility imaging: Ultrasonic measurement of strain due to perfusion
Authors: Kucewicz John C. , Dunmire Barbrina , Huang Lingyun , Paun Marla , Beach Kirk W.
Published: October 2013

Over each cardiac cycle perfused tissues expand and relax by a fraction of a percent as blood rapidly accumulates in the arterial vasculature during systole and then slowly drains through the venous vasculature during diastole. Tissue pulsatility imaging (TPI) is a variation on ultrasonic tissue strain imaging that estimates tissue perfusion from this natural, cyclic tissue expansion and relaxation. TPI is derived in principle from plethysmography, a century-old technology for measuring gross tissue volume change from a whole limb or other isolatable body part. With TPI, the plethysmographic signal is measured from hundreds or thousands of sample volumes within an ultrasound image plane to characterize the local perfusion throughout a body part. TPI measures tissue strain over the cardiac cycle and parametrizes the signal in terms of its amplitude and shape. The amplitude of the strain waveform is correlated with perfusion, and the shape of the waveform is correlated with vascular resistance. Results will be presented from the leg showing the change in the TPI signals as the muscles recover from exercise, from breast tumors, and from the brain as blood flow changes in response to visual stimulation. [Work supported in part by NIH 1-R01EB002198-01 and NIH N01-CO-07118.]
Using human body shear wave noise for passive elastography
Authors: Sabra Karim G. , Conti Stephane , Roux Philippe , Kuperman William A.
Published: October 2013

An elastography imaging technique based on passive measurement of shear wave ambient noise generated in the human body (e.g., due to the heart, muscles twitches, and blood flow system) has been developed. This technique merges two recent research developments in medical imaging and physics: (1) recent work on the efficacy of elastographic imaging demonstrating that shear waves are excellent candidates to image tissue elasticity in the human body and (2) theory and experimental verification in ultrasonics, underwater acoustics, and seismology of the concept of extracting coherent Green’s function from random noise cross correlations. These results provide a means for coherent passive imaging using only the human body noise field, without the use of external active sources. Coherent arrivals of the cross correlations of recordings of human body noise in the frequency band 2–50 Hz using skin-mounted accelerometers allows us to estimate the local shear velocity of the tissues. The coherent arrivals emerge from a correlation process that accumulates contributions over time from noise sources whose propagation paths pass through both sensors. The application of this passive elastography technique for constructing biomechanical models of in vivo muscles’ properties will be discussed.
A phantom study on ultrasonic measurement of arterial wall strain combined with tracking of translational motion
Authors: Hasegawa Hideyuki , Kanai Hiroshi
Published: October 2013

Correlation-based techniques are often applied to ultrasonic rf echoes to obtain the arterial wall deformation (strain). In such methods, the displacement estimates are biased due to changes in center frequency of echoes. One of the reasons for the change in center frequency is the interference of echoes from scatterers within the wall. In the phased tracking method previously proposed for strain estimation by our group, the estimated displacement contains both the components due to the translational motion and strain. The translational motion is larger than strain by a factor of 10 and, thus, the error in the estimated displacement due to the change in center frequency mainly depends on translational motion and is often larger than the minute displacement due to strain. To reduce this error, in this study, a method is proposed in which the translational motion is compensated using the displacement of the luminal boundary estimated by the phased tracking method before correlating echoes between the frame before deformation and that at the maximum deformation to estimate the strain distribution within the wall. In basic experiments using phantoms made of silicone rubber, the estimation error was much reduced to 15.6% in comparison with 36.4% obtained by the previous method.
Wave biomechanics of skeletal muscle
Authors: Rudenko Oleg , Sarvazyan Armen
Published: October 2013

Physiological functions of skeletal muscle, such as voluntary contraction and force development, are accompanied by dramatic changes of its mechanical and acoustical properties. Experimental data show that during contraction, the muscle’s Young’s modulus, shear viscosity, and anisotropy parameter are changed by over an order of magnitude. None of the existing models of muscle contraction and muscle biomechanics can adequately explain the phenomena observed. A new mathematical model [O. Rudenko and A. Sarvazyan, Acoust. Phys. (6), (2006)], has been developed relating the shear wave propagation parameters to molecular structure of the muscle and to the kinetics of the mechanochemical crossbridges between the actin and myosin filaments. New analytical solutions describing waves in muscle including nonlinear phenomena are found. A molecular mechanism for the dependence of acoustical characteristics of muscle on its fiber orientation and the contractile state is proposed. It is shown that although the anisotropy connected with the preferential direction along the muscle fibers is characterized by five elastic moduli, only two of these moduli have independent values in the muscle. The potential implications of the proposed model in terms of the acoustical assessment of muscle function are explored.
Application of the optoacoustic technique to visualization of lesions induced by high-intensity focused ultrasound
Authors: Khokhlova Tatiana , Pelivanov Ivan , Solomatin Vladimir , Karabutov Alexander , Sapozhnikov Oleg
Published: October 2013

Today several techniques are being applied to monitoring of high-intensity focused ultrasound (HIFU) therapy, including MRI, conventional ultrasound, and elastography. In this work a new method for noninvasive monitoring of HIFU therapy is proposed: the optoacoustic method. The optoacoustic technique is based on the excitation of wideband ultrasonic pulses through the absorption of pulsed laser radiation in tissue and subsequent expansion of the heated volume. The excited optoacoustic (OA) pulse contains information on the distribution of optical properties within the tissue—light scattering and absorption coefficients. Therefore, if thermal lesions have different optical properties than the untreated tissue, they will be detectable on the OA waveform. The considerable change in light scattering and absorption coefficients after tissue coagulation was measured using techniques previously developed by our group. Heating induced by HIFU also influences the OA signal waveform due to the rise of thermal expansion coefficient of tissue with temperature. This dependence was measured in order to evaluate the feasibility of the OA technique in temperature monitoring. An OA image of HIFU lesion induced by a 1.1 MHz focused transducer in a liver sample was reconstructed using a 64-element wideband array transducer for OA signal detection.
Hardware and software technologies for improvement of hearing characteristics of headphone reproduction
Authors: Inanaga Kiyofumi , Yamada Yuji
Published: October 2013

This report specifically describes commercialization technology of a headphone system with out-of-head localization applying dynamic head-related transfer functions (HRTFs) that can localize sound easily over a full 360 deg. A source image by output of conventional headphones is localized inside the listener’s head. However, the image can be localized outside the listener’s head by wearing headphones over a full 360 deg through accurate simulation of the listener’s HRTFs. Developments of headphone systems using signal processing technology for data correction have given rise to the static binaural reproduction system (SBRS). The first part of this speech describes its psychoacoustic characteristics and challenges. A rotating dummy-head that is synchronized with the listener’s head movement was produced experimentally to create the dynamic binaural reproduction system (DBRS). Using the DBRS, HRTFs synchronize with the listener’s head movement. Psychoacoustic characteristics and advantages of the system are also discussed in this report. Further developments were made to realize the commercialization of the DBRS in areas including piezoelectric gyroscope head-tracking technology, headphone technologies that can reproduce real sound characteristics, and simplification of HRTF signal processing employing a simulator with electronic circuits. Finally, future visions for these technologies will be touched upon.
Basic study on one-dimensional transducer array using hydrothermally synthesized lead zirconium titanete poly-crystalline film
Authors: Endo Akito , Hasegawa Tomohito , Kawashima Norimichi , Takeuchi Shinichi , Ishikawa Mutsuo , Kurosawa Minoru
Published: October 2013

Recently, high-frequency miniature medical ultrasound probes with high resolution were actively developed. However, it is difficult to fabricate such tiny ultrasound probes using piezoelectric ceramic vibrator with thickness less than 100 μm. We deposited a PZT poly-crystalline film on a titanium substrate using the hydrothermal method and developed transducers using the PZT poly-crystalline film for ultrasound probes. In this study, we applied it to a miniature medical one-dimensional (1-D)-array-type ultrasound probe with resonance frequency of 10 MHz. After sputtering of pure titanium on the surface of a hydroxyapatite substrate, the titanium film was etched using the photolithography method to form a 1-D titanium film electrode array with 75 μm element pitch, 40 μm element width, and 4 mm element length to scan an ultrasound beam electronically by sector scan mode using phased-array technique. Thereby we fabricated a miniature 1-D-array-type ultrasound probe. A transmitted ultrasound pulse from 10 MHz commercial ultrasound probe was received by this fabricated 1-D-array type ultrasound probe with hydrothermally synthesized PZT poly-crystalline film vibrators.
Thermal behavior of high-power active devices with the ATILA (analysis of transducers by integration of LAplace equations) finite-element code
Authors: Debus Jean-Claude , Blottman John , Butler Stephen
Published: October 2013

Many active devices using piezoelectric ceramics are driven with very high power densities and long pulse lengths. Due to mechanical and dielectric losses in the materials, this produces heat, causing a temperature rise in the devices, which may lead to their mechanical failure. The thermal issues have been shown to be the limiting device design criteria over electric field and mechanical stress limits, yet the effect of the temperature on performance is generally not considered in the numerical models used during the design stage. A coupled electro-mechanical thermal analysis is implemented in the ATILA code. For a steady-state or transient solution, a thermal behavior is weakly coupled to the electromechanical response. The method may take advantage of the order-of-magnitude-greater time constant for thermal effects compared to mechanical behavior. A two-step analysis is performed whereby the electromechanical behavior is first computed, and the resulting dissipated power is then applied as a heat generator to determine the resulting temperature of the device. A high-drive, 31-mode, free flooded ring transducer and a sonar projector serve as validation of the numerical model. The approach addresses both the transient thermal response and the steady temperature profile that results from the high-power, high-duty-cycle drive.
Prediction of howling for a sound system in an acoustical environment with both reverberant and direct sounds
Authors: Akiyama Hideki , Ohga Juro
Published: October 2013

Prediction of howling is a key technology for a howling suppression design for a sound system with a loudspeaker and microphone. A howling occurrence prediction method for a sound system in a reverberant room has already been presented [J. Ohga, J. Sakaguchi, ‘‘Prediction of howling of a sound system in a reverberant room,’’ W. C. Sabine Centennial Symposium (ASA, New York, 1994), 2aAAd4]. It is apparently useful for ordinary public address systems whose distances of loudspeakers from microphones are large. However, this result was not perfect because the direct sound component is not negligible in hands-free telephones or teleconference systems whose loudspeakers and microphones are set close to each other. This report gives a quantitative howling occurrence prediction method for a sound system in an acoustical environment with both reverberant and direct sounds. The following design parameters are obtained: (1) the increase of howling occurrence level from the power average value, (2) the level occurrence probability, and (3) the critical level chart given by an equation as a function of direct and reverberant sounds ratio. Prediction results for particular examples are compared with calculations of sound-field transfer functions. Results confirmed that it is practical.
Effect of background noise on dialogue in telephony
Authors: Amamoto Koichi , Ohga Juro
Published: October 2013

Recent developments of mobile telephones include new sorts of impairments against speech. Conventional evaluation method for impairments by a talker and a few listeners cannot apply to these new ones, because they are brought by long signal delay. The effect of it cannot discriminate by ‘‘one-sided’’ test. This research relates to a speech quality evaluation by conversation between two persons. Variation of conversation stream is observed by addition of pink noise of various levels to a dialogue by microphones and earphones. Length of sentences and frequency of repeats are quantified and their meanings are discussed
Multidimensional scaling analysis of centroid- and attack/decay-normalized musical instrument sounds
Authors: Beauchamp James W. , Horner Andrew B. , Koehn Hans-Friedrich , Bay Mert
Published: October 2013

Ten sustained musical instrument tones (bassoon, cello, clarinet, flute, horn, oboe, recorder, alto saxophone, trumpet, and violin) were spectrally analyzed and then equalized for duration, attack and decay time, fundamental frequency, number of harmonics, average spectral centroid, and presentation loudness. The tones were resynthesized both with time-varying harmonic amplitudes and frequencies (dynamic case) and fixed amplitudes and frequencies (static case). Tone triads were presented to ten musically experienced listeners whose tasks were to specify the most dissimilar and most similar pairs in each triad. Based on the resulting dissimilarity matrix, multidimensional scaling (MDS) was used to position the instruments in two- and three-dimensional metric spaces. Two measures of instrument amplitude spectra were found to correlate strongly with MDS dimensions. For both the static- and dynamic-case 2-D solutions, the ratio of even-to-odd rms amplitudes correlated strongly with one of the dimensions. For the dynamic case, spectral centroid variation correlated strongly with the second dimension. Also, 2-D solution instrument groupings agreed well with groupings based on coefficients of the first two components of a principle components analysis representing 90% of the instruments’ spectral variance. [This work was supported by the Hong Kong Research Grants Council’s CERG Project 613505.]
Sound synthesis based on a new micro timbre notation
Authors: Osaka Naotoshi , Baba Takayuki , Kitawaki Nobuhiko , Yamada Takeshi
Published: October 2013

Timbre has become a major musical factor in contemporary and computer music. However, sufficient timbre theory has not yet been established. The author is challenging to create new timbre theory for music composition. The first step of its construction is to make the timbre descriptive. A micro timbre is defined, which is a perceptual impression of a sound with approximately 50 to 100-ms duration, and describe sound as a micro timbre sequence. This can be used as a new notation system in place of common music notation. In dictation, micro timbre sequence and correspondent duration sequence are perceptually recorded. When synthesizing from this notation, sounds corresponding to the notation systems are either physically synthesized or searched for in a large sound database to generate sound data for a given duration. Two sequential sound data instances are first represented in sinusoidal representations and then are concatenated using a morphing technique. Sounds generated by a stream of water and similar sounds are described using the method as examples. Then scripts describing electronic sounds are introduced and explained. The ability to record, transmit to others, and resynthesize timbre is one of the useful functions of the theory.
Timbre representation for automatic classification of musical instruments
Authors: Kostek Bozena
Published: October 2013

Human communication includes the capability of recognition. This is particularly true of auditory communication. Music information retrieval (MIR) turns out to be particularly challenging, since many problems remain still unsolved. Topics that should be included within the scope of MIR are automatic classification of musical instruments/phrases/styles, music representation and indexing, estimating musical similarity using both perceptual and musicological criteria, recognizing music using audio and/or semantic description, language modeling for music, auditory scene analysis, and others. Many features of music content description are based on perceptual phenomena and cognition. However, it can easily be observed that most of the low-level descriptors used, for example, in musical instrument classification are more data- than human-oriented. This is because the idea behind these features is to have data defined and linked in such a way as to be able to use it for more effective automatic discovery, integration, and reuse in various applications. The ambitious task is, however, to provide seamless meaning to low- and high-level descriptors such as timbre descriptors and linking them together. In such a way data can be processed and shared by both systems and people. This paper presents a study related to timbre representation of musical instrument sounds.
An attempt to construct a quantitative scale of musical brightness for short melodies implementing timbral brightness
Authors: Yamada Masashi
Published: October 2013

It is known that a major tune is brighter than a minor one, and that music played in a faster tempo and a higher register is brighter than a slower and lower one. However, it has not been clarified how these factors quantitatively determine the musical brightness. On the other hand, it has been clarified that the timbral brightness of a tone corresponds well to the spectral centroid. In the present study, major and minor scales and two short melodies were played with pure tones, and listeners evaluated their musical brightness. For each performance, the spectral centroid was calculated for the overall-term spectrum during the performance on the transformed frequency scale of the ERB rate. The results showed that the musical brightness of the ascending scale increases proportionally as the spectral centroid shown in the ERB rate increases. Using this, a quantitative scale of musical brightness, BM, was constructed. The results also showed that the difference in the musical brightness between major and minor scales corresponded to the transposition of approximately 5 ERB rate, and doubling the speed corresponded to the upper shift of the centroid in approximately 2.5 ERB rate.
Subjective congruency between a sound effect and a switching pattern of a visual image
Authors: Iwamiya Shinichiro , Arita Motonori , Su Sun
Published: October 2013

The relationship between the transformation of a visual image and the pitch pattern of sound can create formal congruency between sounds and moving pictures. This effect by switching patterns of enlarging and reducing images that were combined with ascending and descending pitch scales was examined. Rating experiments showed two congruent patterns of the combination of switching and scale patterns; one was a combination of an ascending pitch scale and an enlarging image pattern, and the other a combination of a descending pitch scale and a reducing image pattern. These forms of matching might be based on a Doppler illusion. An additional pair of congruent patterns for combinations of switching and scale patterns was also found: one was a combination of an ascending pitch scale and a sliding movement from left to right, and the other a combination of a descending pitch scale and a sliding movement from right to left. These forms of matching might be based on the correspondence of a progressive sensation. Further, the formal congruency between a pitch pattern and the formal transportation can contribute to integrating auditory and visual information and to making audio-visual products more impressive.
A questionnaire survey of the attitude of Japanese and foreign residents in Japan to sound masking devices for toilets
Authors: Ueda Miwako , Iwamiya Shin-ichiro
Published: October 2013

Unique sound masking devices for toilets can be used in women’s restrooms in Japan. Such devices function to produce the sound of flushing water without actual flushing. To mask the sound of bodily functions, women tended to flush the toilet continuously while using it, thereby wasting a large amount of water. In the circumstances, sound masking devices have been introduced to public toilets. We have recently conducted a questionnaire survey to clarify the attitude of people toward such sound masking devices for toilets. The results of the survey showed that many Japanese women know such devices and often use them, that foreign women currently living in Japan also know that such devices exist, and that some Japanese men have heard of such devices but never used them. Many Japanese women are quite embarrassed at the thought that someone else can hear them while they are on the toilet. Many noted the necessity of such devices and required a wide range of setting for toilets in public spaces. However, they are not satisfied with the sound quality of the playback toilet flush sounds of currently available devices. The above results suggest that the sound quality of such devices should be improved.
A review of the vibration and sounds of the crack of the bat and player auditory clues
Authors: Collier Robert
Published: October 2013

The purpose of this paper is to review the state-of-the-art in the acoustics of baseball. As is well known, the crack of the bat is an important phenomenon of solid wood bats and metal bats. Each has a very different sound signature. At the 148th meeting of the ASA in 2004, the author and coauthors Ken Kaliski and James Sherwood presented the results of laboratory and field tests, which showed that the spectral characteristics of radiated sound are dependent on the ball-bat impact location and resultant bat vibration of both solid wood and tubular metal bats. These results will be reviewed together with those of other investigators in the context of player auditory clues and the player’s response in game situations.
New underwater sound system for synchronized swimming: The 9th International Swimming Federation Championships
Authors: Watanabe Takayuki , Kishinaga Shinji , Fukamachi Tokuzo , Maeda Osamu
Published: October 2013

There have been concerns about the differences between underwater sound fields in a temporary fiberglass-reinforced plastic (FRP) pool and in a conventional reinforced concrete (RC) pool. A temporary FRP pool was to be used for competitions at the World Swimming Championships in Fukuoka. We considered three items as key factors for a swimming pool used for synchronized swimming: (1) the sound source itself (output level, fluctuations in frequency characteristics); (2) the effect of materials used in pool construction upon sound source installation conditions; and (3) the effect of the mth mode low-frequency cutoff in ‘‘shallow water.’’ To improve basic problems related to the first factor, we developed a new actuator-driven underwater sound system (YALAS), which can eliminate the effect of installation conditions for underwater speakers in the FRP pool. This new underwater system has now seen practical use in competitions. The report summarizes this new underwater sound system and compares the system with conventional systems in terms of its acoustic characteristics. The system can offer music with sufficient audibility in water. We gained a good reputation with competitors because the system showed superior performance to conventional systems in sound volume and quality, and in uniformity of sound distribution.
Sound inside a gymnasium
Authors: Beristain Sergio
Published: October 2013

A new gymnasium for a sports club was designed taking acoustic confort into consideration, in order to accomodate sports practice, sports events with the public, or musical and drama presentations, taking advatage of its large capacity for the public and performers. The floor plan included room enough for a basketball court with public space on one side, where grades for about 200 people will be permanently installed. Walls were treated in a way that is useful for the sports practice (hard surfaces), with hidden absorption material to reduce the usual reverberant field inside the court, and to allow for sound events with only the addition of a mat (to protect the floor woodwork) and extra grades and the sound reinforcement system.
Occupational and recreational noise exposures at stock car racing circuits
Authors: Kardous Chucri A. , Morata Thais , Van Campen Luann E.
Published: October 2013

Noise in stock car racing is accepted as a normal occurrence but the exposure levels associated with the sport have not been adequately characterized. Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted an exploratory assessment of noise exposures to drivers, pit crew, team staff, and spectators at three stock car racing events. Area measurements were made during race preparation, practice, qualification, and competition. Personal dosimetry measurements were conducted on drivers, crew members, infield staff, and spectators. Findings showed time-weighted averages (TWA) that ranged from 94 decibels A-weighted (dBA) for spectators to 114 dBA for car drivers. Peak sound-pressure levels exceeded the maximum allowable limit of 140 decibels (dB) during race competitions. Personal exposure measurements exceeded the NIOSH recommended exposure limit (REL) of 85 dBA as an 8-h TWA in less than a minute for one driver during practice, within 2 min for pit crew and infield staff, and 7 to 10 min for spectators during the race. Hearing protection use was variable and intermittent among crew, staff, and spectators. Among drivers and crew, there was greater concern for communication performance than for hearing protection.