bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of thickness-shear modes excited by two layers of piezoelectric films in acoustic sensors
Authors: Zhang Hui , Zhang Shu-yi , Fan Li , Wang Yu-ran
Published: April 2012

The thickness-shear mode (TSM) excited by two layers of (112(–)0) textured hexagonal piezoelectric films are studied to improve the performances of acoustic sensors. The corresponding researches are carried out by the acoustic wave propagation model which considers the effects of the acoustic attenuations. When the acoustic field and electric field satisfy to a special match condition, i.e. the phase variation of TSM at each film equal to π, both piezoelectric layers with opposite polarization directions reduce the first TSM and generate the second TSM with higher frequency and higher quality factor than the first TSM excited by two-layers of piezoelectric films with identical polarization direction. Furthermore, the second enhanced TSM holds a moderate the ratio of the operating frequency to the quality factor. These properties of the TSM are appropriate for improving the mass sensitivity and sensitive resolution of the acoustic sensors in liquid medium. Acknowledgment: This work is supported by National Natural Science Foundation of China (No. 11004099 and 11174142), State Key Laboratory of Acoustics of Chinese Academy of Sciences, and also PAPD of Jiangsu Higher Education Institutions.
Theoretical study of interaction of the acoustic waves in different crystals
Authors: Liu Xiaozhou , Zhang Tingting , Gong Xiufen
Published: April 2012

In isotropic solids, transverse acoustic waves propagate undistorted and the interaction of collinear transverse waves is forbidden. In this study, It is found that transverse and longitude waves behave differently in anisotropic solids and the different formulas are given for the interaction of transverse and longitude acoustic waves propagating in different kinds of crystals including cubic, trigonal, tetragonal, hexagonal crystals. The formulas are expressed in terms of the derivatives of the strain energy. The formulas are used to calculate the interaction coefficients in the general anisotropic medium emphasizing the influence of nonlinearities. The evolution equations are derived for the wave amplitudes and find analytical formulas for all interaction coefficients of quadratically nonlinear interacting waves. The equations of motion show that transverse and longitude waves are distort as they propagate and interact. It is observed that two acoustic waves with frequency can produce harmonic waves with sum and difference frequency. This shows evidence that the intrinsic nonlinearities of an anisotropic solid can induce an interaction of acoustic waves. This project is supported the National Basic Research Program of China (Grant Nos. 2012CB921504, 2011CB707902), financial support of the National Natural Science Foundation of China (Grant No. 11074122), fundamental Research Funds for the Central Universities (Grant Nos. 1113020403, 1101020402), State Key Laboratory of Acoustics, Chinese Academy of China (Grant No. SKLOA201005) and A project funded by the priority academic program development of Jiangsu higher education institutions.
Effects of changes in the depth feeling of the visual target on the simultaneity perception of an auditory-visual event
Authors: Hasegawa Hiroshi , Ishikawa Tomoharu , Kasuga Masao , Ayama Miyoshi
Published: April 2012

In this study, we investigated the simultaneity perception between a visual stimulus and its associated sound. We carried out experiments of an auditory-visual stimulus presentation using an audio-video clip of a man beating a drum on a road. The visual stimulus had a feeling of depth with a perspective view of the road. There were four kinds of distance between the visual target of a man beating a drum and the video camera to capture the target of 5, 10, 20, and 40m, and we called these distances as “the presentation distances.” We presented the auditory-visual stimuli to experimental subjects at each presentation distance of 5, 10, 20, and40 m under various conditions, where we varied the feeling of depth of the visual stimulus from -40% to 40% and the time delay between the auditory and visual stimulus from -8F to 8F (1F = 1/30s). We analyzed the experimental results and calculated the point of subjective simultaneity (PSS) of the auditory-visual event. As a result, the PSS intended to increase as the feeling of depth increased of the visual stimulus. This result shows that changes in the depth feeling of the visual stimulus could influence the simultaneity perception.
Robustness of audio-visual spatial disparity in peripheral field
Authors: Miyauchi Ryota , Kang Dea-Gee , Iwaya Yukio , Suzuki Yôiti
Published: April 2012

In our previous studies, a perceptual phenomenon, audio-visual peripheral spatial disparity (AVPSD), has been found. The spatial coincidence of perceived locations of a sound and flash presented in the peripheral field varies from their coincident physical location. Since the stimulus condition used in the previous experiments was limited, three new experiments were conducted to investigate the robustness of the spatial disparity between the perceptual and physical locations of the sound and flash. In Experiments 1 and 2, the frequency characteristics of the sound and the repetition of stimulus appearance were respectively changed from those used in the previous experiments. In Experiment 3, the presentation timing of the sound or the flash was delayed for one second. The results of Experiments 1 and 2 show that the spatial disparity was robustly appeared. In contrast, the spatial disparity disappeared in Experiment 3. These results suggest that the features of the stimulus pattern do not affect the spatial disparity, but the simultaneity of the sound and flash plays an essential role. Acknowledgment: This research was supported by a Grant-in-Aid for Specially Promoted Research (No. 19001004) and Grant-in-Aid for Young Scientists (B) (No. 21730584).
Comparison of frequency lowering algorithms on Mandarin speech recognition
Authors: Zhang Yunyi , Cui Jie , Xiao Ling
Published: April 2012

This paper examined several frequency lowering algorithms for improving speech recognition in Chinese listeners with high-frequency sensorineural hearing loss, including both frequency compression and frequency transposition algorithms. The frequency lowering algorithms were evaluated by a subjective listening test. Monosyllabic words in Mandarin spoken by a female and a male talker were used as speech materials. Speech materials processed by frequency compression and frequency transposition were presented to normal-hearing listeners in the listening tests, as well as the control condition of unprocessed speech. More benefits in speech recognition were observed with speech spoken by female talker than by male talker. It was showed that frequency lowering made little difference for some words while words with dental consonant were most infected by frequency lowering. The results indicate that Mandarin recognition for high-frequency hearing loss may benefit from frequency lowering in some cases, while whether choosing frequency lowering or not and which algorithm to choose depends on individuals.
Acoustic cues used by blind travelers
Authors: Simon Helen , Gilden Deborah , Brabyn John , Lotze Al , Levitt Harry
Published: April 2012

People with vision loss rely heavily on subtle environmental sound cues for safe and efficient travel (“Wayfinding”). Using our laboratory-developed instruments, the acoustic cues available to blind individuals, with and without hearing loss, during real-life pedestrian travel were recorded. Acoustic signals picked up by electret condenser microphones in the ear canals were fed to a wearable digital audio recorder. Head and body movements were monitored by accelerometers and gyroscopes mounted on the heads and torsos of subjects during typical travel situations such as walking along a corridor with an open doorway. A skilled wayfinder can detect the presence of an open doorway from the acoustic characteristics of the ambient sound field (the “acoustic signature”). The salient characteristics of the acoustic signature when passing an open door were found to be below 1500 Hz. These data confirm previous work regarding ambient room noise near a wall and an opening (Ashmead, 1999). Unlike previous work, the current study also measured the interaural characteristics of the acoustic signature. The results of this investigation will be used to develop the design requirements of a special-purpose hearing aid for people with both vision and hearing loss. (Funded by NIDRR and Smith-Kettlewell Eye Research Institute.)
A cross-language study of breathing rhythm related to different linguistic structures in Chinese and Korean
Authors: Oh Hanna
Published: April 2012

This paper investigates correlations between respiration patterns and different linguistic structures in Chinese and Korean.The study includes comparative analysis between the Korean and Chinese scripts of poetry and news with same meaning and different languages, and the subjects included 4 native speakers (2 males, 2 females) for each language. It can be made certain by measuring physiological and acoustic parameters by means of two respiratory sensors for chest and abdomen and electroglottalgraphy. Preliminary results show that due to the poetry has fixed frame, therefore regardless of language and sex, the respiratory rhythm of the poetry is quite similar in two languages. In contrast, for news scripts, the data show that breathing groups of the Chinese quite correspond to intonation units. In contrast,the Korean is more flexable in planning breathing rhythm,generally breathing resets appears not only in intonation phrase but in accentual phrase,and chest respiration is mostly used for the accentual phrase. It suggests that different linguistic structures operate powerfully upon preplanning and respiratory patterns. Furthermore, the results show the correlation of voice quality variation and respiratory rhythm in different languages.
High-frequency complex pitch: a search for temporal cues and for a role of spectral indices
Authors: Santurette Sébastien , Dau Torsten , Oxenham Andrew J.
Published: April 2012

Harmonics in a complex tone are typically considered unresolved when they interact with neighboring harmonics in the cochlea and cannot be heard out separately. Recent studies have suggested that the low pitch evoked by unresolved high-frequency harmonics may be coded via temporal fine-structure cues. However, these conclusions rely on the assumptions that combination tones were properly masked and that the ability of listeners to hear out individual partials provides an adequate measure of resolvability. Those assumptions were tested by measuring the audibility of combination tones and their effects on pitch matches, the effects of relative component phases and of dichotic presentation, and listeners' ability to hear out individual partials. The results confirmed that combination tones affected pitch, but pitch remained salient when they were masked. The lack of dependence of pitch on relative component phases or dichotic presentation provided no evidence in favor of temporal cues. Moreover, similar trends were observed between pitch salience and the listeners' ability to hear out individual partials. The results are consistent both with the use of place information and with a temporal code based on the combination of information across auditory channels. [Supported by the Danish Research Foundation and by NIH grant R01DC05216.]
Amplitude modulation detection by human listeners in reverberant sound fields: carrier bandwidth effects and binaural versus monaural comparison
Authors: Zahorik Pavel , Kim Duck O. , Kuwada Shigeyuki , Anderson Paul W. , Brandewie Eugene , Collecchia Regina , Srinivasan Nirmal Kumar
Published: April 2012

Previous work [Zahorik et al., POMA, 12, 050005 (2011)] has reported that for a broadband noise carrier signal in a simulated reverberant sound field, human sensitivity to amplitude modulation (AM) is higher than would be predicted based on the broadband acoustical modulation transfer function (MTF) of the listening environment. Interpretation of this result was complicated by the fact that acoustical MTFs of rooms are often quite different for different carrier frequency regions, and listeners may have selectively responded to advantageous carrier frequency regions where the effective acoustic modulation loss due to the room was less than indicated by a broadband acoustic MTF analysis. Here, AM sensitivity testing and acoustic MTF analyses were expanded to include narrowband noise carriers (1-octave and 1/3-octave bands centered at 4 kHz), as well as monaural and binaural listening conditions. Narrowband results were found to be consistent with broadband results: In a reverberant sound field, human AM sensitivity is higher than indicated by the acoustical MTFs. The effect was greatest for modulation frequencies above 32 Hz and was present whether the stimulation was monaural or binaural. These results are suggestive of mechanisms that functionally enhance modulation in reverberant listening. [Work supported by the NIH/NIDCD.]
Examining enhancement conditions with an auditory nerve model
Authors: Hegland Erica , Strickland Elizabeth
Published: April 2012

Psychophysical studies have shown that the ability to detect a signal in a masker may be improved by presenting a preceding sound (precursor) identical to the masker, an effect called overshoot. When the masker has no spectral notch around the signal frequency, overshoot has been predicted using a physiologically-realistic auditory nerve (AN) model in which gain is reduced by the precursor. This may simulate the medial olivocochlear reflex (MOCR). When there is a spectral notch in the masker at the signal frequency, the resulting improvement in signal detection is sometimes called enhancement. It has been suggested that enhancement may be due to adaptation of suppression, which could be related to gain reduction in the cochlea, or to adaptation of inhibition, which could occur more centrally. Physiological studies of the AN have shown either no adaptation of suppression [Palmer et al., J. Acoust. Soc. Am. 97, 1786-1799] or a reduction in suppression when the MOCR was elicited [Kawase et al., J. Neurophys. 70, 2533-2549]. The purpose of the present experiment is to use the AN model to investigate the relationship between gain reduction and suppression with stimuli used in previous studies of enhancement. [Research supported by NIH(NIDCD) R01 DC008327]
Modeling the effects of sensorineural hearing loss on temporal coding in the auditory nerve
Authors: Axe David , Heinz Michael
Published: April 2012

Recent psychoacoustical studies have suggested a temporal-fine-structure (TFS) deficit in listeners with sensorineural hearing loss (SNHL). Physiological studies generally have not found a reduction in the strength of TFS coding in auditory-nerve responses; however, a number of other effects on temporal coding have been found that may be related to these perceptual temporal processing deficits [e.g., Kale and Heinz, JARO (2010); Scheidt et al., Hear. Res. (2010)]. These physiological effects of SNHL include enhanced envelope (ENV) coding, changes in relative TFS/ENV coding that depend on stimulus bandwidth, broadened tuning, loss of tonotopicity for complex sounds, reduced latencies and traveling-wave delays, and altered temporal dynamics such as enhanced onset responses, faster adaptation, and slower recovery from stimulation. The current study evaluated which of these physiological effects were accounted for by an existing computational model of auditory-nerve responses [Zilany et al., JASA (2009)], and the extent to which these properties are predicted to depend on outer- vs. inner-hair-cell dysfunction. The degree to which existing models account for these effects of SNHL on temporal coding will help to elucidate the responsible mechanisms, and is important for future diagnostic and rehabilitative applications. [Work supported by NIH Grant No. R01DC009838.]
A modified channel model for the auditory peripheral system
Authors: Oh YongHee , Hoglund Evelyn M. , Feth Lawrence L.
Published: April 2012

The correlated channel model (Zhang, 1995) was proposed as a modification of the (Durlach, et al., 1986) channel model by assuming that the internal noise in each peripheral channel is correlated. However, both models are limited because signals resolved into N channels by the peripheral processing unit are assumed to be statistically independent. Based on the results of several recent studies, the signals themselves may be correlated due to nonlinear properties of the basilar membrane, even before the addition of interchannel noise. In this study, the correlated channel model was extended using correlated and weighted signals, and the sensitivity index d' for a multi-tone detection task was derived. The performance of the modified model was characterized by parameter estimation, and compared with the results of a spectrotemporal integration experiment. [Research supported by a grant from the Office of Naval Research # N000140911017.]
Medial olivocochlear influence on stimulus-frequency otoacoustic emission input-output functions
Authors: Dewey James , Dhar Sumitrajit
Published: April 2012

Modulation of cochlear mechanics by the medial olivocochlear efferent system is characterized by a reduction in active, outer hair cell-mediated amplification of basilar membrane motion. This increases cochlear thresholds and linearizes basilar membrane input-output functions for low-to-moderate stimulus levels. Significant efferent effects have also been observed for responses to higher stimulus levels, potentially reflecting changes in the mechanical properties of the cochlear partition. In humans, sound activated changes in stimulus-frequency otoacoustic emissions have been used as a tool for investigating the dynamics of the medial olivocochlear reflex. However, the degree to which the amplitude and phase of otoacoustic emissions are related to those of basilar membrane motion is not entirely clear. For the purposes of comparison with invasive physiological measurements in animals, stimulus-frequency otoacoustic emission input-output functions were obtained from human subjects in the presence and absence of contralateral acoustic stimulation. Medial olivocochlear effects were quantified in terms of the absolute change in emission level as well as the vector change, which incorporates changes in emission phase. The extent to which efferent modulation of emissions in humans reflects that observed in previous reports of basilar membrane motion will be discussed.
Development of an evaluation system for cochlear implant
Authors: Yang Zhenya , Wang Sheng , Yuan Meng , Feng Haihong
Published: April 2012

The cochlear implant (CI) stimulation parameters such as pulse width, phase gap, pulse amplitude, and stimulation rate are the key and fundamental features in the objective evaluation of a CI device. In this study, an electronic evaluation system was developed to measure the above CI parameters for fully understanding the performance of a CI device. This system is multi-functional, powerful and flexible, which contains several modules, e.g. source signal generation, I/O synchronization, pulse sequence acquisition, data processing, and pulse/waveform display. A user-friendly graphic interface was developed including many useful functions and options to make different measurement and evaluation. The measurement results and original data can be easily exported from the evaluation system for further analysis. The accuracy and limitation of the system will also be discussed in this work. This system is suitable for CI parameter verification, speech processing research strategy evaluation, multi-electrode streaming, and CI quality examination. This work is supported by National Natural Science Foundation of China (11104316), and Shanghai Natural Science Foundation (11ZR1446000).
Subjective experiment on preferable reverberation of a musical practice room by professional players
Authors: Nakajima Akihiro , Yokoyama Sakae , Tsujimura Sohei , Sakamoto Shinichi , Tanaka Ami , Shiba Yoshihide
Published: April 2012

A musical practice room is very important space for players to improve their skills. However, no architectural design guideline of the musical practice room exists in Japan and the individual room is being designed based on architect's intuition and experiences. For a basic investigation aiming to establish the guideline, we are now investigating appropriate acoustic conditions of musical practice rooms for players by subjective experiments. In this study, we focused on reverberation time of the room and subjective experiments using a three dimensional sound field simulation were conducted for professional players including woodwind instrument players, string players and singers. In the experiment, a room having 6 conditions of reverberation time was virtually simulated in the sound field simulation system established in an anechoic chamber. As a result, a clear tendency of preferable reverberation time dependent on the difference of types of the instruments was found and a range of preferred reverberation time for a practice room was obtained.
Measurement of acoustic characteristics in a traditional Korean Buddhist temple complex
Authors: Skorski III Edwin Stephen
Published: April 2012

Traditional Korean Buddhist Temple complexes, typically found in rural, mountainous settings, hold great cultural, historical, and architectural significance in the Republic of Korea. These buildings, constructed primarily of wood, with little or no mechanical fasteners, create unique acoustic environments used for chanting, spoken word, music, and quiet meditation. Within the temple complex there are multiple halls and shrines of varying size and geometry that are utilized for worship. This presentation documents the room acoustic characteristics of a variety of worship spaces within a prototypical traditional Korean Buddhist Temple complex. These spaces include the main Buddha Hall as well as surrounding halls dedicated to additional Buddhas and Bodhisattvas. Using a laptop based measurement system; field measurements were conducted to document reverberation time (RT), clarity (C-50), speech transmission index (STI), and background noise levels. Data gathered is discussed and analyzed in regards to the primary use of each space. This research was conducted utilizing BISA Research Grant funds provided by Keimyung University.
A review on bio-sonar behaviour research of Yangtze finless porpoise using animal bone acoustic data loggers
Authors: Wang Ding , Akamatsu Tomonari , Wang Kexiong , Li Songhai
Published: April 2012

In recent 10 years, a miniature stereo acoustic data logger (A-tag, W20-AS, Little Leonardo, Japan) has been used to observe the bio-sonar behaviour of free-ranging Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis). The A-tag is small enough to be attached on the one of the smallest odontocetes by using suction cups. The A-tag with two external hydrophones can record the sonar pulse intensity, inter-click-intervals, and sound source direction measured by time arrival difference of sounds at the two hydrophones. Major outcomes by A-tag were the in situ off-axis sonar beam pattern, attention and approach phase of biosonar behaviour, scanning sonar of rolling animals, and social contacts among free-ranging Yangtze finless porpoises. In addition, frequent ultrasonic sound production was confirmed that seemed to be a reason of high detection performance of this species using passive acoustic monitoring of finless porpoises. This biosonar monitoring method using miniature data logger system developed in a freshwater system in China provided new insights of underwater behaviour of other small odontocetes producing high-frequency echolocation clicks, such as harbour porpoises and white-beaked dolphins.
Acoustic characteristics measurement of rat liver by multi-frequency ultrasound microscopy
Authors: Inoue Kenta , Saijo Yoshifumi , Kobayashi Kazuto , Mamou Jonathan , Yamaguchi Tadashi
Published: April 2012

Hepatitis is a growing health concern and early disease detection is critical. Ultrasound is ideally suited for real-time imaging of liver, but typical ultrasound images do not display quantitative tissue information because it is first necessary to understand the complex interaction between ultrasound and tissue and scattering models based on tissue properties must be devised. Towards this aim, speed-of-sound (SOS) and attenuation from three types of rat livers (normal, fatty, and fibrosis) were measured with a scanning acoustic microscope using transducers with center frequencies from 1-MHz to over 100-MHz. Results indicated that SOS and attenuation measured with each transducer showed the following trend. Variability in SOS and attenuation values of normal liver was much smaller than other livers at any frequencies. In the fatty liver, SOS was 20 m/s slower and the attenuation was 1.0 dB/cm/MHz larger than in the normal liver. In fibrosis, SOS and attenuation had values between those of normal and fatty liver. Additionally, the relation between the pathologic state of liver and SOS and attenuation was investigated. Correlation between the ultrasound wavelength and the distribution and size of fat or fiber deposits in the liver was investigated using the corresponding stained histology photomicrograph.
A free-flooded flextensional transducer with tube-beam coupling structure
Authors: Pan Yaozong , Mo Xiping , Liu Yongping , Chai Yong , Zhang Yunqiang
Published: April 2012

The transducer consists of two annulus steel end plates, a tube stacked by piezoelectric rings as the driving element and a dual slotted concave aluminum shell coupled one end plate to the other. The shell has two concave parts and an annulus ring between them; and each part is equally slotted into several beams with gaps between each other. The tube and the beams form the tube-beam coupling structure. A sealing boot is covered on both inner surface of the stack and outer surface of the shell so that the water could freely flood through the ring stack. Some vibrating modes of the transducer including a cavity resonance are used to broaden the band. A prototype is fabricated and measured. The cavity resonant frequency is about 1250Hz with the transmitting voltage response of 130dB and the TVR fluctuates less than 6dB from 1800Hz to 5700Hz. This work was supported by the National Natural Science Foundation of China (No. 11074276).
A new type of wide band and wide beam longitudinal transducer
Authors: Chai Yong , Mo Xiping , Liu Yongping , Pan Yaozong , Zhang Yunqiang
Published: April 2012

A new type of wide band and wide beam longitudinal transducer is introduced in this paper. The beam width could be expanded significantly by union of the special design about the shape of the head mass and a bucket tail mass which could both enhance radiating ability and reduce the longitudinal size. And the working bandwidth could also be expanded efficiently by using mode coupling between the flex mode of the head mass and the longitudinal mode. Using the finite element analysis, some major electro-acoustic parameters of a prototype transducer with a size of 74mm in maximum outside diameter and 76mm in total length are computed. It is shown that the projector has good performance. The resonance frequency is about 14kHz with a transmitting voltage response of 141dB. The Q factor for -3dB bandwidth is 1.3 and the beam width for -6dB bandwidth would be over 200 degrees.
Controlling environment noise—a hong kong experience
Authors: Au Hom , Cheng Kin Wui , Lin Flora Kit Mei
Published: April 2012

Controlling environmental noise in a metropolitan city, like Hong Kong, has always been a challenge to both the Authority and the industries. This is partly attributable to the past neglect in environmental planning during the early 80s', and partly to the compacted urban settings in Hong Kong. Strategically, the Environmental Protection Department has attempted to pre-empt noise problems through early inventions in projects' planning stage, while in parallel effort was made to address existing noise problems through abatement programs and enforcement of the noise control legislation. This paper briefly outlines the overall framework being implemented in Hong Kong, both legislatively and administratively, to control different kinds of environmental noise sources. Some of the crucial thoughts in the framework and the experience gained through enforcing the relevant legislative provisions will be discussed.
“Background” noise levels in mining towns—a case study
Authors: McNeillie Chris
Published: April 2012

Legislation and planning policy often stipulate “background plus” criteria for assessing the noise impact of industry and validating noise related complaints. However, these criteria generally do not take into account the fact that industrial noise may be an established and accepted part of the noise environment of an area. This paper presents a case study of an assessment of a large-scale mining operation in central Queensland, Australia where mine noise contributed significantly to the background noise level in an adjacent Township. The paper explains why a true background plus approach was not appropriate and describes how, instead, 3D noise modelling was used to “benchmark” existing mine noise emissions for the purposes of controlling future increases.
Environmental noise from wind farms, prediction and measurements
Authors: González Alice Elizabeth
Published: April 2012

Although mechanical noises of wind turbines have been eliminated with the development in their design, aerodynamic noise generation during operation is inherent to them in nature. Their major acoustic emission occurs in low frequencies. To predict noise levels in the environment associated with the operation of stationary sources-wind turbines included-, the methodology of ISO 9613-2 is usually recommended. It is not only a standard method of calculation but it is also the recommended methodology in the European Union. However, under some conditions (such as a stable atmosphere) the predictions of this method may significantly underestimate the expected environmental noise levels. Lately, other methodologies of prediction that take in account atmospheric stability have been developed. Nevertheless, predictions from different calculation methods do not always result on the same sound pressure levels. Different prediction methods are compared in this article. Their accuracy is then evaluated by checking environmental sound pressure levels with the predicted ones. Some issues that should not be neglected at the moment of working with noise emission sources of great height are remarked.
A study on the transfer matrix and dynamical characteristics of flexible pipe bend
Authors: Changgeng Shuai , Zhiqiang Lv
Published: April 2012

Much of the noise originates from pressure and flow fluctuations generated by pump. These pressure fluctuations are transmitted along the hydraulic lines and cause unbalanced forces at pipe bends and changes of section. The flexible pipe bend, a recently developed flexible component of pipe, can usually reduce thermal expanding reaction and endure large and complex stress and strain arising from different movements and also due to complex geometry. The rubber hose wall can conduct oscillating longitudinal forces that may interact with fluid waves inside. Up to now, little attention has been paid to study its performances of vibration damping and noise attenuation in pipeline. The transfer matrix, an effective numerical method, is applied to analyze and evaluate the transfer performance of flexible pipe bend. However, because of its geometrical complexity, it is difficult to directly calculate the transfer matrix of the flexible pipe bend. In this paper, the flexible pipe bend is divided into several parts, each of which can be considered as a short straight pipe. Through the conversion between the global coordinate system and local coordinate system, a transfer matrix of the flexible pipe bend is derived and applied, which provide a practical method to analyze the frequency, modal and response of the flexible pipe bend.
Innovative approach of acoustic design of high performance facade with auralization at Arup SoundLab
Authors: Ng C. W. , Chan Henry C.K. , Tsoi Sam P.S.
Published: April 2012

This paper presents an innovative approach of acoustic design of high performance facade for buildings in the vicinity of an airport. The sound insulation performance of the facade system is established by an aircraft noise auralization of the aural environment in the built environment such as a Star hotel at Arup SoundLab for determining an acoustically suitable glazing system. Arup SoundLab uses a 3D loudspeaker reproduction system called Ambisonics to reproduce the sound phenomena in a dedicated room that allows people to listen to simulated sound in virtual spaces before actual construction. The audio samples can be generated to mimic the dynamic indoor acoustic environment for the takeoff noise profile of B747 aircraft. After listening to the audio samples for different glazing configurations and ambient conditions, subjective responses from a group of representative individuals to the audio sound track that simulates a possible future situation are collected for evaluation analysis. The engineering development of high performance acoustic facade is presented including laboratory testing to reach a confidence level for achieving the end results. An opportunity for identifying potential cost saving is also discussed as a result of this aircraft noise auralisation. Examples will be presented to illustrate the approach.
Innovative arc screen development for adaptive traffic noise mitigation of housing development using full scale prototype testing
Authors: Tsoi Sam P. S. , Lai C. C. , Lau C. K. , Wong Kenneth H. K.
Published: April 2012

The Housing Authority is responsible for public housing development in Hong Kong. With increasing demand for sites of challenging environmental conditions, the authority has been continuously diverting efforts on innovative design to tackle site environmental issues. One of the frontline development is an innovative arc-screen structure, which was devised to become one of the new generations of adaptive traffic noise mitigation. Its inception was initiated from the need to reduce traffic noise impact of a major highway parallel to the public housing development in Sai Chuen Road. As scale model evaluation of traffic noise reduction is somewhat limited, the project commissioned a full scale testing of an arc-screen prototype built into a 3-storey full size stacking up housing flat model for evaluation. This is believed to be the first time of a full scale experimental evaluation of traffic noise mitigation for housing development. The arc-screen structure has achieved 5 dB(A) nominal noise attenuation performance. Results are encouraging for public housing development applications and will form new generations of adaptive architectural forms of arc-screen uses to suit different needs. The first application is already planned at the Sai Chuen Road development and in-situ performance evaluation will be assessed in second phase.
Use optical beams to push and pull: an old paradigm with new features
Authors: Qiu Cheng-Wei
Published: April 2012

We present a fundamentally distinguished schematic for a novel micromanipulation which realizes stable trapping and continuous optical traction/pulling of molecules at one go, opening up its widely appealing potentials in physics and biomedical engineering. We theoretically investigate the origin of pulling force by modeling tractor beams and its explicit correlations on the laser types, particle's parameters, and beam polarization modulation. The novel technology of tractor beam is developed and proposed via a systematic analysis from electromagnetic scattering theory, condition of pulling force, and experimental investigation by using binary-lens optics. Instead of treating the object as a “blackbox” and interfering multiple beams, our technique exploits a single beam with phase modulation, and more importantly we study the fundamentals of the energy exchange, force direction switching, and the far-field radiation flipping. The major criterion is to manipulate the beam-particle interference to maximize the transfer of momentum along the forward direction, so that the reaction force will be dragging the particle all the way towards light source continuously, i.e., the fantasy of tractor beam.
Attraction by sound—examples on the negative acoustic radiation forces of Bessel “tractor” beams on a sphere
Authors: Silva Glauber , Mitri Farid
Published: April 2012

Expressions for the axial (i.e. acting along the axis of wave propagation) and transverse (lateral) acoustic radiation forces on a suspended object in an ideal fluid are derived for arbitrary shaped beams. These expressions are obtained from the integration of the radiation stress tensor in the far-field. Numerical examples on non-vortex and vortex Bessel beams on a spherical target are presented. It is demonstrated the existence of both “pushing” and “tractor” behaviors for which the axial force can be oriented, respectively, along the direction of wave propagation or opposite to it. This can be adjusted by choosing specific values of the beam cone angle and the sphere size factor ka (where k is the wavenumber and a is the sphere's radius). Furthermore, by changing the topological charge m of the beam and the position of the sphere, the transverse force may be oriented radially (outward or inward) for m=0 or may exhibit a vortex pattern for m ≥ 1.
Acoustic trapping of particle by a periodically structured stiff plate
Authors: Cai Feiyan , Li Fei , Meng Long , Zheng Hairong
Published: April 2012

Acoustic tweezers have found potential applications in both the physical and life sciences in the past two decades due to their abilities of contactless, controllable and noninvasive trapping and manipulating micro-scale objects regardless of material transparency. Approaches to acoustic trapping of micro-objects required large field intensities. They are usually generated directly by acoustic transducer, cannot be redesigned easily, nor can the corresponding acoustic radiation forces be modulated efficiently. Recently, the artificial structures, such as phononic crystal or metamaterials, can provide a facile way of controlling the field distribution of acoustic wave. These artificial fields may have potential application in acoustic manipulation. In this work, we demonstrate that a geometrical modulated trapping force can exert on an object as it is near the surface of structured artificial brass plate at resonance frequency. The mechanism and condition of this trapping effect are discussed via the field and force analyzing, respectively.
Parameter space for scattering and radiation forces for symmetric objects based on unimodular partial-wave s-functions
Authors: Marston Philip L. , Zhang Likun
Published: April 2012

For situations in which dissipation is negligible it can be helpful to parameterize the scattering and radiation forces on axisymmetric objects using partial-wave s-functions [L. K. Zhang and P. L. Marston, Phys. Rev. E 84, 035601 (2011)]. The reason is that without dissipation, for axisymmetric objects illuminated by axisymmetric beams along the axis of the object, for each partial wave the scattering becomes characterized by a single parameter: the partial-wave phase shift. As a consequence of the finite diameter of the object, only a limited number of partial waves need to be included in the analysis of the radiation force and the scattering. In the case of a sphere illuminated by an electromagnetic beam, there are separate electric and magnetic partial waves. In the simpler acoustic case, the phase shifts and the cone angle of a Bessel beam may be used to characterize regions of negative radiation force and large scattering asymmetry. Fabrication of the associate object becomes a separate issue. It is not difficult to select the partial-wave phase shifts such that reduced backscattering with negative radiation forces occur with a cone angle of the beam as small as 22 degrees. [Supported by ONR and NASA.]
An experimental study of acoustically induced rocking motion of simple asymmetric geometries
Authors: Rodgers Gwendolyn V. , Rogers Peter H. , Martin James S.
Published: April 2012

A series of experiments were done to test theoretical predictions that an acoustically small, rigid (aluminum) hemisphere and semicircular cylinder excited by a plane acoustic wave in water would each produce a rocking motion perpendicular to the incident wave direction about the axis parallel to the incident wave. A plane standing wave was generated in a short open-ended thick-walled cylindrical waveguide with the waveguide's axis perpendicular to the symmetry axis of the hemisphere. Measurements were taken along the hemisphere from top to bottom to determine if any rocking motion occurred. The expected vibrational motion in the incident direction and symmetry-forbidden perpendicular vibrational motion were also measured. The transverse displacement of the hemisphere at each point was determined by using an ultrasonic vibrometer. The incident wave direction motion was measured using a hydrophone, an accelerometer, and a Laser Doppler Vibrometer (LDV). The motion in the incident wave direction was found to be more than 10 times greater than the maximum rocking displacement for each case.
Influence of SPL distribution on loudness impression for environmental noise
Authors: Chaki Yuta , Yoshida Junji
Published: April 2012

To realize comfortable living environment, it is necessary to reduce the environmental noise according to the suitable environmental noise evaluation index. For considering the environmental noise evaluation index, it is important to know characteristics of loudness evaluation toward long-term noise because the environmental noise was evaluated for long-term. In this study, to investigate the evaluation characteristics, we focused on the distribution of sound pressure level in duration of environmental noise and performed loudness evaluation test using long-term noise by changing the distribution. In the test, four traffic noises in duration of 10 min which loudness was adjusted equality by pre-processing were employed as base sounds. In addition, modified four noises in which the deviation of sound pressure level were increased (the mean value was same as the base sounds) were used as target sounds. Fourteen subjects evaluated the loudness of eight traffic noises immediately after hearing each sound. As a result, it was found that loudness impression toward the target sound was evaluated to as softer than the base sound. Consequently the long-term sound having large deviation of sound pressure level was clarified to be evaluated softer than the sound having small deviation.
Annoyance perception of environmental noises by hearing impaired listeners
Authors: Vishnubhotla Srikanth , Xiao Jinjun , Xu Buye , McKinney Martin , Zhang Tao
Published: April 2012

Annoyance perception of environmental noises is an important topic in many fields, including transportation, environmental studies and hearing aid design. While annoyance perception of normal hearing (NH) listeners has been studied extensively (e.g. Fastl & Zwicker 2006, Versfeld & Vos 1997, Alayrac et al 2010, Palmer et al 2006), data on annoyance perception of hearing impaired (HI) listeners is scant. In this study, we investigate the annoyance perception of typical environmental noises by both NH and HI listeners, using listeners with unilateral hearing loss. We use the magnitude estimation procedure to obtain the annoyance ratings and a paired-comparison method to obtain the annoyance preference for different environmental noises. The experimental data are analyzed to reveal the underlying dimensions of annoyance perception and differences between NH and HI listeners. A functional model for annoyance perception is developed for both HI and NH listeners. Finally, potential applications of our results are discussed in the context of hearing aid design.
Ménière's disease impaired hearing character and improving strategy
Authors: Zhang Yan-Ping , Long Xian-Ming , Long Chang-Cai
Published: April 2012

Hearing ability of Ménière's disease victim is usually impaired. They have a higher hearing threshold and a lower discriminating ability of speech, especially in noise enviroment. We demonstrate in psychoacoustics experiment that accompanying the usually observed hearing loss phenomena, the tuning shape of the disease victim is also changed into shallower. This phenomena can be explained by our physics theory about nonlinear cochlea signal procesing and a improving strategy is alao provided.
Silver Medal in Engineering Acoustics
Authors: Elko Gary W.
Published: April 2012

The Silver Medal is presented to individuals, without age limitation, for contributions to the advancement of science, engineering, or human welfare through the application of acoustic principles, or through research accomplishment in acoustics.
Gold Medal of the Acoustical Society of America
Authors: Kuperman William A.
Published: April 2012

The Gold Medal is presented in the spring to a member of the Society, without age limitation, for contributions to acoustics. The first Gold Medal was presented in 1954 on the occasion of the Society's Twenty-Fifth Anniversary Celebration and biennially until 1981. It is now an annual award.
The Calming Effect of
Escherichia coli
Authors: Shrout Joshua D.
Published: April 2012

Pathogenic bacteria stealthily induce a host enzyme that minimizes the immune response during urinary tract infection.
Not Just the Heart of the Matter: Cholesterol’s Role in Emphysema
Authors: Zeki Amir A.
Published: April 2012

High cholesterol, macrophage activation, and systemic inflammation may link atherosclerosis to emphysema.
Surrogates of Survival
Authors: Oviedo-Orta Ernesto
Published: April 2012

Regulatory T cell numbers can be measured in the blood of glioblastoma patients to predict survival after treatment with a dendritic cell vaccine.
Mechanisms of traumatic shoulder injury in elite rugby players
Authors: Crichton James , Jones Doug R , Funk Lennard
Published: April 2012

Background

Shoulder injuries in rugby players are common, but the mechanisms of injury are less well understood. This study aims to elucidate common mechanisms of injury and identify the patterns of injury they produce.

Materials and methods

Twenty-four elite rugby players, referred to the senior author for diagnosis and management of shoulder injuries, were selected. Videos of the injuries were independently reviewed by rugby-medical experts to describe the mechanisms of injury. The mechanisms reported were collated and analysed to determine the level of agreement between reviewers and conclude an overall description of injury mechanisms.

Results

The authors identified three mechanisms of shoulder injury from the video analysis. These are the ‘Try-Scorer’, characterised by hyperflexion of the outstretched arm such as when scoring a try; the ‘Tackler’, extension of the abducted arm behind the player while tackling; and the ‘Direct Impact’, a direct blow to the arm or shoulder when held by the side in neutral or slight adduction. The Try Scorer and Tackler mechanisms both involve a levering force on the glenohumeral joint (GHJ). These mechanisms predominantly cause GHJ dislocation, with Bankart, reverse Bankart and superior labrum anterior–posterior tears. The Try-Scorer Mechanism also caused the majority (83%) of rotator cuff tears. The Direct Hit mechanism resulted in GHJ dislocation and labral injury in 37.5% of players and was most likely to cause acromioclavicular joint dislocation and scapula fractures, injuries that were not seen with the other mechanisms.

Conclusion

Greater understanding of the mechanisms involved in rugby shoulder injury is useful in understanding the pathological injuries, guiding treatment and rehabilitation and aiding the development of injury-prevention methods.