bluuebunny/crossref_metadata_2025 huggingface dataset:
Photolyses of carboxy-hemoglobin of bar-headed goose studied by photoacoustic calorimetry
Authors: Zhao Jin-yu , Li Jia-huang , Zhang Zheng , Qu Min , Zhang Shu-yi , Hua Zi-qian , Hua Zi-chun
Published: April 2012

As a specialized species native to high altitude, bar-headed goose can fly annually over an altitude of 9000m, which means that its hemoglobin has a higher oxygen affinity than its lowland relatives, such as goose and chicken. To study the mechanism of the phenomena, laser ultrasonic calorimetry is used to study dynamic processes associated with photolyses of carboxy hemoglobin (HbCO), including the enthalpy and conformational volume changes, of bar-headed goose and its lowland relatives. Considering the time scales of the reaction lifetimes in the photolyses processes of HbCO, two kinds of piezoelectric transducers, a PVDF film and a PZT ceramic, are used as acoustic signal detectors. For evaluating the relative enthalpy change and the relative conformational volume change in the process, the quantum yield of the photolysis must be taken into account, which has been measured by pump-probe technique. The results show that the enthalpy and conformational volume changes of bar-headed goose are obviously smaller than that of its lowland relatives and human. Some analyses and discussions on the differences of the amino acid sequences of Hb, the tetramer structures, as well as the salt bridges between subunits of Hb and HbCO among them are presented.
Design of a home-made, low-cost system for studies of vibratory courtship signals on Pardosa Sierra (Areneae: Lycosidae) spiders
Authors: Romero-Vivas Eduardo , Méndez Salinas Emiliano , Jiménez Jiménez María Luisa , García De León Francisco Javier
Published: April 2012

Spiders possess peculiarities that make them attractive for the study of evolutionary phenomena such as adaptation and specialization. Among these processes, reproductive behavior (particularly courtship) is a main factor, allowing or preventing recognition between potential partners. Spiders sense their environment and communicate using chemical, visual and acoustical/vibrational signals. The study of the nature, variation and content of these signals, provides useful information to understand the role of communication in the formation of species. Vibrational signals excel in importance in the majority of spider families and have been previously studied, especially in leaf-living spiders, using non-contact laser Doppler vibrometers or accelerometers (adding extra mass to the system) coupled to charge amplifiers. Unfortunately, cost and availability of this equipment have limited the widespread of studies in this area. This paper describes how to build an alternative low-cost system for the study of vibrational signals on spiders, and presents the analysis of the acquired vibratory courtship signals of Pardosa sierra, a rocky substrate-dwelling lycosid spider.
The Lombard effect in humpback whales
Authors: Noad Michael , Dunlop Rebecca , Cato Douglas
Published: April 2012

The Lombard reflex is an increase in the subject's vocal levels in response to increased noise levels. While it has been demonstrated in humans and a small number of mammals and birds including some whales, it has not been demonstrated in humpback whales. During their southward migration off eastern Australia humpback whales were tracked visually from an elevated land station. An array of calibrated hydrophone buoys was used to simultaneously track vocalizing whales acoustically and to measure ambient noise. Two hundred and ninety two social vocalizations were recorded and analysed from 15 passing groups of whales when there was no detectable boat noise or singing whales in the area. Vocalization source levels increased significantly by a mean of 0.75dB per 1dB increase in background noise (broadband 40Hz – 2kHz). Unlike most previous Lombard studies, however, the vocal level increased even though the background noise was much lower than the vocal level. Thus the whales maintained a signal excess of approximately 75dB which suggests that these social vocalizations may function as signals over distances of several kilometres.
Acoustic issues in studies of behavioral response of humpback whales to seismic ramp-up and hard start
Authors: Cato Douglas , McCauley Robert , Noad Michael , Dunlop Rebecca , Kniest Hendrick , Gales Nicholas , Salgado Kent Chandra , Patton David , Noad John , Jenner Curt , Duncan Alec , Maggi Amos
Published: April 2012

Two large behavioral response studies (BRS) have been conducted with humpback whales migrating along the east Australian coastline (in project BRAHSS: Behavioural Response of Australian Humpback Whales to Seismic Surveys). Whales were exposed to four stages of ramp-up with nominally 6 dB increase in level at each step, and a hard start nominally 12 dB above the first stage. Observations of behavior were made by theodolite teams ashore and small boats following specific whale groups, DTAGs, and binoculars from the source vessel. The sound field throughout the area was recorded using five buoys that radioed data back to the shore station, four autonomous receivers and two drifting systems with a vertical array of four hydrophones. Measurements show that the propagation loss at the site is variable and includes patches of anomalously high loss. This complicates estimation of the sound levels received by whales, but may not be unusual in near shore environments. This paper presents preliminary results of the project to illustrate acoustic issues involved in designing and executing comprehensive BRS, including characterization of sources and the acoustic environment experienced by the whales, and monitoring cumulative exposure at individuals for mitigation.
Therapeutic ultrasound on bone cellular and in vivo adaptation
Authors: Qin Yi-Xian , Zhang Shu , Ferreri Suzanne , Cheng Jacky
Published: April 2012

Objective: It is well documented that ultrasound, as a mechanical signal, can produce a wide variety of biological effects in vitro and in vivo. The purpose of the current study was to (1) develop a methodology to allow for in-vitro manipulating osteoblastic cells using acoustic radiation force generated by ultrasound, (2) use this methodology to determine the morphological and biological responses of bone cells to ultrasound, and (3) mitigate bone loss under estrogen deficient osteopenia. Methods: In Vitro Cellular Manipulation: We used a therapy focused transducer, which has spherical cap with 64 mm diameter and 62.64 mm focal length. A laser guide MC3T3-E1 osteoblastic cells were cultured in α-MEM containing 1% penicillin-streptomycin and 10% decomplemented newborn calf serum. In Vivo OVX Model: 72, 16 w.o. Sprague-Dawley rats were divided into six groups; baseline control, age-matched control, OVX control, OVX + 5 mW/cm2 ultrasound (US), OVX + 30 mW/cm2 US and OVX + 100 mW/cm2 US. Low intensity pulsed ultrasound (LIPUS) was delivered transdermally at the L4/L5 vertebrae, using gel-coupled plane wave US transducers. The signal was applied 20 min/day, 5 days/week for 4 weeks. Results: In Vitro Cellular Response: The developed methodology allowed manipulation of MC3T3-E1 cells by acoustic radiation force. The deformation of cell membranes was observed by the US manipulation, which appeared after 15s treatment of pulsed ultrasound in 6W. We also imaged the movement of primary cilia, which showed corresponding movement when subjected to pulsed ultrasound. In Vivo Response: LIPUS treatment significantly increased BVF compared to OVX controls for the 100mW/cm2 treated group. Interestingly, the 100mW/cm2 treated groups showed a significant improvement over the 5mW/cm2 treated group. Discussion and Conclusions: Pulsatile focused ultrasound can create local fluid flow nearby cells. The observed primary cilia can be triggered to dynamic movement by the acoustic force as a mechanobiologic effect. In vivo results suggest that low-intensity pulse ultrasound can induced mechanical wave in tissue and initiate bone adaptation. These findings support the hypothesis that LIPUS can inhibit bone loss and preserve bone strength under conditions of estrogen deficient osteopenia. Keywords: quantitative ultrasound, therapeutic ultrasound, bone mechanotransduction, osteoporosis, bone remodeling
Effect of trabecular material property on ultrasonic backscattering in cancellous bone
Authors: Liu Chengcheng , Ta Dean , Wang Weiqi
Published: April 2012

Ultrasonic backscattering technique, used to assess cancellous bone status, is investigated using numerical simulations based on two-dimensional finite-difference time-domain (FDTD) method. High resolution microstructure mappings of bovine cancellous bone, provided by micro-CT, are used as the input geometry for simulations. This paper focused on the effects of material property parameters (density, lamé coefficients, viscosities, and resistance coefficients) of the trabecular on ultrasonic backscattering measurements at 1MHz. Simulations of ultrasonic backscattering in cancellous bone for different trabecular parameters were carried out and the backscatter coefficient (BSC) were measured and discussed. The results demonstrate that BSC is a nonlinear function of trabecular density and increases with trabecular density. While BSC is affected little by the viscosities, the first and second lamé coefficients have a complex effect on BSC. BSC is almost a linear function of normal resistance coefficient (NRC) and decreases with increases of NRC. On the other hand, BSC is practically independent of the shear resistance coefficient, just because there is little shear wave in backscattered signals. The results demonstrated that ultrasonic backscattering is affected by trabecular density and other material acoustic properties, as well as the bone mineral density and microarchitecture.
Bayesian-derived fast and slow waves correlate with porosity obtained from microCT
Authors: Hoffman Joseph , Nelson Amber , Holland Mark , Miller James
Published: April 2012

It has previously been shown by our laboratory that Bayesian probability theory permits separation of ultrasonic fast and slow waves in cancellous bone even when the modes overlap substantially in time. The goal of the current study was to determine whether the fast and slow waves obtained from Bayesian separation of an apparently single mode signal individually correlate with porosity. The Bayesian technique was applied to data from cancellous bone samples from 8 human heels insonified with a broadband 500 kHz ultrasound pulse in the medial/lateral direction. The phase velocity (SOS), slope of attenuation (nBUA), and relative amplitude were determined for both the fast and slow waves. The porosity of the samples was measured by X-ray microCT. The phase velocity and slope of attenuation for both the fast and slow wave modes showed an inverse correlation with porosity. The fast wave amplitude decreased with increasing porosity. Conversely, the slow wave amplitude increased with increasing porosity. These results indicate that the properties of the individual fast and slow waves correlate with bone porosity, an important determinant of fracture risk. Supported, in part, by NIH/NIAMS grants R01AR057433 and P30AR057235.
Modeling and simulation of acoustic scattering in poroelastic materials
Authors: Ou M. Yvonne
Published: April 2012

In this talk, we will present a model based on Biot's equation and numerical simulation of wave propagation in a fluid-elastic-poroelastic system, with scattering of a bone sample of cancellous bone surrounded by cortical layer and muscle layer in mind. The numerical methodology is based on the finite volume method and the operator splitting technique, combined with the grid-mappings technique and CLAWPACK. This is joint work with Randall LeVeque and Grady Lemoine form University of Washington.
Direct comparison of single mode versus fast and slow wave modes analyses of calcaneal bone data
Authors: Nelson Amber , Hoffman Joseph , Holland Mark , Miller James
Published: April 2012

Background: We previously demonstrated that a signal transmitted through cancellous bone might be comprised of two interfering (fast and slow wave) modes even though it appears to consist of only a single mode. Objective: The goal of this study was to compare the results of single mode analysis and two mode analysis to quantify the effects of interfering waves on the measured speed of sound (SOS) and broadband ultrasound attenuation (BUA). Methods: A series of human calcaneal samples (bone volume fractions = 0.09 to 0.21) were measured medial-laterally using 500kHz broadband focused transducers. Phase velocity was determined by phase spectroscopy and attenuation was determined by log-spectral subtraction. The original radiofrequency signal and the Bayesian-separated fast and slow wave radiofrequency signals were analyzed. Results: For each of the specimens, the slope of attenuation determined by single mode analysis was larger than that for either the fast or slow wave, and the speed of sound determined by single mode analysis lay between that of the fast and slow wave. Conclusion: The additional information provided by analyzing individually fast and slow wave modes might enhance the effectiveness of bone sonometry. Supported by NIH/NIAMS grants R01AR057433 and P30AR057235.
Air-coupled sensing of leaky rayleigh waves and ZGV modes in concrete slabs
Authors: Zhu Jinying , Tsai Yi-Te , Dai Xiaowei , Haberman Michael R.
Published: April 2012

Rayleigh waves and zero-group velocity (ZGV) Lamb modes (the impact-echo test) are commonly used for non-destructive evaluation (NDE) of concrete structures to extract information about material property and interior delaminations. Traditional methods in civil engineering employ point impactors to generate the waves while accelerometers measure the resulting out-of-plane motion. Though well-established, this methodology does not lend itself to efficient scanning of large areas, which is critical for monitoring the safety of infrastructure. The ability to detect these two wave types through in-air sensing of Leaky Rayleigh or ZGV Lamb waves can greatly accelerate NDE for large structures. Unfortunately, air-coupled sensing suffers from significantly decreased signal amplitude. This paper presents theoretical analysis and experimental validation efforts to amplify in-air signals resulting from Leaky Rayleigh waves and ZGV Lamb modes using a parabolic focusing mirror. A time-domain impulse response to the Kirchhoff-Helmholtz integral equation is presented that permits the analysis of discrete arrivals from each wave type and estimation of the expected focusing gain and depth of field based on the geometry of the parabolic dish. Analytical and numerical solutions in time-domain are compared with time-harmonic solutions taken from the literature and experimental results. This work is supported by NIST Technology Innovation Program (TIP).
Toward a high power non-contact acoustic source using time reversal
Authors: Le Bas Pierre-Yves , Ulrich TJ , Anderson Brian , Esplin John
Published: April 2012

Over the last decades, nonlinear acoustic techniques have been developed to detect mechanical damage in solids. They have been proven to be far more sensitive to early damage than standard linear acoustic techniques. Unfortunately, they often require high amplitude waves to propagate within the sample. To be practical in industrial applications, signals have to be generated without contact. Currently available non-contact transducers are generally not powerful enough. A first step toward the creation of a high amplitude non-contact acoustic source will be described. This source is based on the principle of focusing energy on the surface of a sample using Time Reversal in a hollow cavity. By using a laser vibrometer for the necessary calibration of the system we are able to use a full non-contact process. New development in signal processing allows a much cleaner signal generation than usually achieve with time reversal. This source is proven to be much more energetic than current off the shelf non-contact transducers. It is a broad band source with an adjustable standoff distance and also has the capability to selectively generate in-plane waves. This work is supported by the U.S. Department of Energy through the LANL/LDRD Program.
Noncontact MASW methods for near surface soil/infrastructure assessment
Authors: Lu Zhiqu
Published: April 2012

In near surface geophysics, a multi-channel analysis of surface wave (MASW) method has been increasingly applied for underground infrastructure assessments, in which conventional contact sensors like geophones and accelerometers were mostly employed to detect surface vibrations. In this study, noncontact sensors technology such as a laser Doppler vibrometer (LDV) and a microphone were used to measure Rayleigh wave and leaky Rayleigh waves respectively. These noncontact sensors were installed in a scanning platform that was driven by a stepper motor. The scanning MASW system consisted of two excitation sources: an electromechanical shaker and steel-balls to generate frequency sweeping (chirp) signals with frequency from 30 Hz to 500 Hz and high frequency (up to 40 kHz) impulsive signals respectively. The LDV-shaker-MASW was developed for near surface soil profile exploration and the microphone-steel ball-MASW was built for pavement assessment. The details of the system and several case studies will be addressed.
A grinding acoustic emission monitoring method using wavelet transforms and fuzzy logic
Authors: Jing Yang , Zhong-Ning Zhang , Jian-Chun Cheng , Xiang-Xiong Liu
Published: April 2012

It is known that the acoustic emission (AE) signals contain potentially valuable information for grinding wheel and work conditions during automatic grinding process. However, AE signals produced in the grinding zone are usually much more complicated and it is difficult to obtain enough effective information directly from raw AE signals. This paper presents an efficient grinding AE monitoring method based on a combination of wavelet transforms and fuzzy Logic techniques. First, the discrete wavelet transforms are used to extract the feature vectors from AE signals with different grinding wheel and work states. Secondly, a fuzzy classifier is employed to build a nonlinear relationship between the feature vectors of AE signals and the various grinding states. This method requires less computation and has a low sensitivity to the changes of grinding conditions. Experiment results show that the proposed intelligent monitoring system can identify the different grinding wheel and work states accurately and is valuable for industrial applications.
Research on target-matching method in ultrasonic testing
Authors: Zhang Han , An Zhiwu , Wang Xiaomin , Mao Jie , Li Mingxuan
Published: April 2012

Ultrasonic echoes contain ample flaw information in nondestructive testing. However, bad coupling or small flaw often leads to low SNR (signal-to-noise ratio), so the result provided by conventional amplitude detection may not be accurate enough. To solve this problem, the finite element method is used to investigate the frequency domain characteristics of flaw echoes. Furthermore, a target-matching method based on the maximum output SNR criteria is proposed. The transducer is excited by a certain electrical signal obtained by adaptive filtering deconvolution algorithm for each flaw, so we get a maximum SNR when the excitation signal and flaw match. This is further verified in ultrasonic test for a series of samples containing different sizes of flat-bottom holes. This work is supported by the National Natural Science Foundation of China (Grant Nos. 10834009, 11074272)
Study on improving piezoelectricity and PBLG/PMMA composite
Authors: Jeon Junsik , Hwang Yonghwan , Yu Micheal S , West James E , Moon Wonkyu
Published: April 2012

Poly-Gamma-benzyl-L-glutamate Poly methyl methacrylate (PBLG-PMMA) composite polymer, a new piezoelectric transduction material, was invented by Yu et al. In our previous study, we have shown that the body composed of this new material can be produced by simultaneous poling and curing of a homogeneous solution comprising Poly-Gamma-benzyl-L-glutamate(PBLG) and methyl methacrylate(MMA) via detachable molding. And, it was also shown that the piezoelectric coefficient(d33) of PBLG-PMMA composite is dependent on the PBLG concentration and the intensity of electric field applied during curing in molds. In this study, we attempt to improve piezoelectricity of PBLG-PMMA composite because the piezoelectric coefficient of PBLG-PMMA was only about one twentieth of that of PVDF and measure the dynamic behaviors of PBLG-PMMA bodies in order to investigate the feasibility to apply this composite to acoustic transducers. In order to improve the piezoelectricity, the PBLG concentration and the electric field intensity applied during fabrication processes are increased. Our efforts result in making the piezoelectric coefficient about three times higher than it in previous study. We also measured the dynamic behaviors of a PBLG-PMMA disk. Then, a Tonpilz transducer was designed, fabricated using PBLG-PMMA composite disks, and tested experimentally. [Work supported by Grant No. ADDUD080004DD.]
Deposition of ZnO films with c-axes lying in R-sapphire substrate planes
Authors: Wang Yan , Zhang Shu-yi , Wasa Kiyotaka , Shui Xiu-ji
Published: April 2012

The (110) textured ZnO films with c-axes lying in R-sapphire substrate planes are deposited by RF magnetron sputtering. The focusing investigation is the effect of substrate position in the sputtering on structural and acoustic properties of the ZnO films on the sapphire. The crystallographic characteristics of the films are characterized by X-ray diffraction (XRD) analysis. It is found that the crystalline orientation of the ZnO film varies with the substrate position deflected from the center of the target. The XRD spectra of the films show that there is an optimized substrate position, at which the strongest (110) peak of the ZnO film can be obtained. However, with the decrease or further increase of the deflection, the (110) diffraction intensity decreases and additional diffraction peaks of (002), (102) and (103) emerge. In order to investigate the variations of acoustic properties of these films, the ZnO piezoelectric films are deposited on R-sapphire substrates with different deflection positions, and the bilayered structures are used to fabricate film bulk acoustic resonators (FBARs). The results show that the electromechanical coupling coefficients k15 of the shear mode acoustic waves excited by FBARs also vary with the different positions similar to that shown by the XRD spectra.
Noise generation by a cylindrical cavity in subsonic flow
Authors: Marsden Olivier , Bogey Christophe , Bailly Christophe
Published: April 2012

Following a previous experimental study of the noise generated by cylindrical cavities placed in subsonic flows, this work investigates mechanisms involved in the noise generation by a cylindrical cavity placed in a turbulent boundary layer, via numerical simulation. The cavity has a radius of r =5 cm and a depth of 10 cm. Flows are computed at Mach numbers of 0.2, 0.26 and 0.32, and the numerical boundary layer, of thickness 17 mm, is perturbed upstream of the cavity. Simulations are performed by solving the unsteady compressible Navier-Stokes equations using low-dispersion and low-dissipation finite-difference schemes. The LES approach is based on the explicit application of a selective filtering to the flow variables to take into account the dissipative effects of the subgrid scales. Numerical results are compared to the available experimental data presented in previous work, including mean flow aspects, flow statistics and acoustics. The numerical results are then examined in more detail in particular with regard to the origin of the well-defined tones observed in the acoustic far field. A simple feedback model coupling shear layer dynamics with depth mode acoustic resonance is shown to yield good frequency predictions.
Aeroacoustics of flow merging at duct junction
Authors: Lam Garret C. Y. , Tang S. K. , Leung Randolph C. K.
Published: April 2012

Although merging flow at duct junction is always encountered in fluid-transporting systems, previous works were mainly devoted to study the acoustics of duct junction but the aeroacoustics of flow merging has received little attention. Therefore, this paper aims at revealing the mechanism of sound generation by a merging flow at a 30-degree duct junction. The flow problem is investigated numerically by solving the unsteady compressible Navier-Stokes equations and the gas equation of state simultaneously, thus allowing the acoustic field and the aerodynamic field to be determined without modelling the source terms in the wave equation. The Conservation Element and Solution Element (CE/SE) method is chosen as the solver, which has been successfully applied in tackling many aeroacoustic problems. The results show that a shear layer is created between the two flows at duct junction due to the velocity gradient across the flow. Furthermore, another shear layer is also formed at downstream to the edge of duct junction. However, only the latter one rolls up to form vortices, which are believed to be the acoustic source. The contributions of these flow dynamical processes to sound generation and the identification of dominant sources will be discussed.
Preliminary analysis of acoustic measurement from ARJ21 flyover test
Authors: Chen Zhifei , Yang Jianhua , Hou Hong
Published: April 2012

A flight test was performed on the airport of Yanliang in June, 2010 for the noise source identiofication of ARJ21. The airframe noise was recorded using a ground-based multi-arm logarithmic spiral array with diameter as 30 meters. A data set of five taking off and eight approaching flight with extended landing gears has been acquired during four days. Conventional beamforming and deconvolution approach for the mapping of acoustic sources (DAMAS) are applied for the data analysis. The beamforming results could clearly distinguish two engines and the nose landing gear. Their spectrum characterizations are also presented together with a description of the experimental set-up.
A nodal discontinuous Galerkin method for computational aeroacoustics and comparison with finite difference schemes
Authors: Chen Eryun , Yang Ailing , Zhao Gaiping
Published: April 2012

A nodal discontinuous Galerkin formulation, which is based on Lagrange polynomials basis, is used to directly simulate the acoustic wave propagation. Two test problems of wave propagation with initial disturbance consisting of a Gaussian profile or rectangular pulse are investigated. We evaluate the performance of the schemes in short, intermediate, and long waves. Moreover, the comparisons of numerical results between the nodal discontinuous Galerkin method and finite difference type schemes are performed, which indicate that the numerical solution obtained using nodal discontinuous Galerkin method with a pure central flux has obvious high frequency oscillations for initial disturbance consisting of rectangular pulse, which is the same as those obtained using finite difference type schemes without artificial selective damping. If an upwind flux is adopted, spurious waves are eliminated effectively except for the location of discontinuities. When a limiter is used, obviously the spurious short waves are almost completely removed. The quality of the computed solution has greatly improved.
Aerodynamic noise prediction model of pantograph for high-speed train
Authors: Yi Sukkeun , Park Junhong
Published: April 2012

In this study, to analyze aerodynamic noise from the pantograph on high-speed train, numerical model was established. We study the mechanism of the noise generation by setting up the simple model and finally analyze entire pantograph model. Based on the Lattice Boltzmann Method, computational fluid analysis was carried out. Through noise analysis for near field, sound radiation for far field was estimated using Ffowcs Williams and Hawkings Equation. Simple model is the square and circular cross-sectional cylinder. This model makes noise by flow separation accompanied by vortex shedding. Considering pantograph have a series of the rods, we made a complex structure which have square and circular cross-sectional cylinder. By analyzing entire pantograph model we suggest the model for predicting the noise generation and radiation.
Prediction of aerodynamic sound radiation from pantograph of high-speed train
Authors: Yi Sukkeun , Park Junhong
Published: April 2012

Based on the Lattice Boltzmann method, aerodynamic noise from the pantograph of high-speed trains was investigated. The mechanism of the noise generation was analyzed using a simple panhead model, and the numerical procedures were extended to analyze sound radiation from the whole pantograph system. The square and circular cross-sectional cylinders were used to simulate the panheads. The primary noise was generated by flow separation accompanied by vortex shedding. Since the pantograph were consisted of a series of the rods, the primary noise generation characteristics were similar to the simple panhead. From the numerical model, the design of the pantograph for reduced aerodynamic noise generation is proposed and validated.
Synthesis of performance expression of bowed string instruments using “Expression Mark Functions”
Authors: Koizumi Yuma , Itou Katunobu
Published: April 2012

This paper proposes a method for synthesis of performance expression of bowed string instruments. In order to reflect a creator's intention on a synthetic sound, physical model is efficient because the sound can be synthesized by the performance imagination. The physics of the bowed string instruments are still some issues remain unresolved, bowed string sound synthesis using only the physical model is difficult. In this paper, a method using a transfer function for expression mark is proposed. “Expression mark functions” is estimated from recorded performance sounds, using spectrum of string motion and inverse filter of resonant properties of the instruments. Bowed String motion is a triangular wave called the Helmholtz wave, and it can be determined from bowed string position. Changes of waveform from expression performance were estimated by non-negative matrix factorization. Resonant properties of an instrument were measured as TSP response using a “direct conduction speaker”. The expression mark functions of the performance is extracted by decomposing the actual performance. For evaluation of the quality of the synthesized sound, the scale by ten kinds of expression marks was synthesized using expression mark functions, and the questionnaire estimated the degree of agreement in five steps.
Investigation of optimum shape for an acoustic guitar by electroanalysys of tone quality
Authors: Itako Kazutaka , Itako Satoshi
Published: April 2012

The shapes of acoustic guitars are strongly governed by the sensibilities of the craftsmen who make them, and thus, shapes vary widely. Unlike violins and other instruments, no ideal shape has yet been established for guitars. In our research, we conducted an electroanalysis of tone quality with the aim of manufacturing a guitar with enhanced tone quality. In this study, we examined the effects of varying guitar body thickness and chamber cubic volume on tone quality with various playing methods, and quantitatively identified the optimal thickness.
A study on active noise control using multi-pole control sources
Authors: Ichikawa Hiroyuki
Published: April 2012

In Active Noise Control (ANC), the difficulty of global control is one of the issues to be tackled. Basically, a lot of control sources and corresponding sensors are needed to realize effective control in large area. In the present study, a new type of secondary source arrangement, the multi-pole source array, is proposed. The idea is based on the Kempton's approach using multi-pole expansion, which was proposed in 1970's. This method is expected to have a capability of realizing more flexible shapes of wavefront compared with conventional control source arrays. The effect of proposed array sources is examined in the free field and in the diffracted field with thin semi-infinite barrier. The results of the numerical simulations and the preliminary experiment indicate the superiority of the proposed method.
The Fortaleza noise mapping project—a tool for the definition of noise action plans for the airport located in the center of the municipality
Authors: Brito Francisco Aurélio Chaves , Coelho Jose Luis Bento
Published: April 2012

Studies of the impact of noise from Fortaleza International Airport, located well within the urban area, based on the noise mapping project that was created for the spatial representation of indicators of ambient noise in the city of Fortaleza, Brazil, which provided a tool essential to analyze and define strategies for the control of noise pollution in the city. This is the first noise map drawn to scale in a large city in Brazil. Noise emissions from major sources that contribute to the sound environment of the city, including road traffic, railway noise, aircraft noise, industrial noise, noise and entertainment areas were included. The method followed a hybrid approach, essentially calculating complemented with experimental measurements for validation and calibration. The study of airport noise allowed detailed results for equip lawsuit against the noise produced during operation of the airport.
Enhancement of soundscapes using natural sounds in urban spaces
Authors: Hong Jooyoung , Jeon Jin Yong
Published: April 2012

Design elements of urban soundscape were investigated through individual soundwalk and laboratory experiments. Soundwalking was performed in Seoul; thirty subjects selected evaluation sites when they perceived positive and negative soundscape elements in the soundscape route. It was found that soundscape elements are closely related to visual elements. In order to investigate the effects of the design elements on soundscape perception, laboratory experiments were designed: birds' singing and water sounds were selected as acoustic stimuli enhancing the urban soundscapes. Trees and water features were also added as visual stimuli which were connected to the acoustic elements. The experiments consisted of three parts; 1) audio-only condition, 2) visual-only condition, and 3) audio-visual condition. As a result, the contributions of soundscape elements to urban soundscape perception were derived.
Validation of the Swedish soundscape quality protocol
Authors: Axelsson Östen , Nilsson Mats E. , Berglund Birgitta
Published: April 2012

The Swedish Soundscape-Quality Protocol was developed to help non-experts (e.g., officials working for municipalities rather than soundscape researchers) to make informed, accurate measurements of soundscape quality. The Protocol has hitherto been used in England, France, Italy, Spain, Sweden, and The Netherlands; a Korean version is being developed. Based on field studies – soundwalks in urban residential areas, recreational areas, and parks – the present paper reports on the psychometric properties of the scales of the Protocol. Participants were residents, or visitors to the areas and their results support the reliability and validity of the scales in the Protocol. Because high acoustic quality has a greater effect in visually attractive than in visually poor areas, the Swedish Soundscape-Quality Protocol includes scales for cross-sensory tabulation. These are sound source identification – sounds from humans, nature and technology – attribute scales (e.g., eventful, exciting, pleasant, and calm), overall soundscape quality, and concomitant visual impressions. In brief, the Swedish Soundscape-Quality Protocol is an easy to use and practical tool for measuring soundscape quality. It has the potential to help operationalize how soundscapes can be measured in “quiet areas” to meet a future guideline value of the World Health Organization.
An aural and visual study on the urban open space in Shenzhen Dongmen shopping district using ANN models
Authors: Yu Lei , Kang Jiang , Liu Huan
Published: April 2012

The Dongmen shopping district is the oldest shopping market in Shenzhen. Since 1995, the district has become one of ten famous commercial pedestrian-streets in China. Located in a bustling area of Shenzhen, the Dongmen shopping district attracts a large number of people in its tight-street spaces. An open space is therefore designed, which is important for customers to have a rest after exhausted shopping. It is also a relaxing place for the nearby residents. However, the space quality does not match its recreation function. According to an on-site investigation, subjective evaluations of physical comfort in the space are rather poor, including the aural and visual evaluations. Therefore, this paper is going to investigate how subjective evaluations of aural and visual “scapes” influence physical comfort. Based on analyses of aural and visual evaluations and physical comfort evaluation, artificial neural network (ANN) models of predicting subjective evaluations of physical comfort of the open space in Dongmen are explored. Using the best-trained model, a design with various aural and visual “scapes” for the space is reviewed. It is expected that this study can provide an optimised design scheme for the Dongmen open space in its refurbishment programme in terms of the physical comfort.
Noisy spring?—bird song as a component of urban soundscape perception
Authors: Liu Jiang , Behm Holger , Coppack Timothy , Gan Yonghong , Luo Tao
Published: April 2012

Where do we stand 50 years after Rachel Carson's (1962) scenario of “a strange stillness” that crept over “a town [...] where all life seemed to live in harmony with its surroundings”? Today, research on urban acoustics is focused more on noise control than on those factors that contribute positively to overall environmental quality. Thus, it seems that no significant progress has been made in our concept of an ideal urban environment. The soundscape approach, which considers not only unfavourable noises, but also desirable environmental sounds, could help to achieve this goal. Here, this hitherto neglected aspect of the urban soundscape was focused on. A field investigation was conducted on human perception of bird sounds in an urban area in Germany. First, the role of bird song as a positive soundscape element was confirmed. Then a series of analysis were performed, including characterization of daily spatial patterns of bird sounds, their contribution to overall soundscape, their relationship with other urban soundscape components, and the connection between avian sounds and urban landscape functions. At last, how bird song could improve urban environmental quality was discussed and possible strategies from an urban planning and a conservation perspective was suggested. Acknowledgement: Project supported by National Natural Science Foundation of China(40971111), Natural Science Foundation of Fujian Province, China (2011J01280), and German Academic Exchange Service(DAAD).
Laser ultrasound technique for material characterization of thermal sprayed nickel aluminum coatings in elevated temperature environment
Authors: Yeh Cheng-Hung , Yang Che-Hua , Su Cheng-Yuh , Hsiao Wei-Tien
Published: April 2012

Thermal spraying processing usually use nickel-aluminum alloy system as major powder due to its strong adhesion to substrates. The contents of powder material and the processing parameters used in the spraying process cause material properties of coating exhibiting a wide variation. It is difficult to investigate mechanical properties of coating layer in nondestructive way. This research focuses on characterizing mechanical properties of thermal spraying coatings at high temperature environment up to 295° C in nondestructive way. A laser ultrasound technique (LUT) is used for the measurements of dispersion spectra of guided waves. Theoretical model for surface waves propagating along a multi-layered structure with coating and substrate is used to model the sprayed coatings. An inversion algorithm based on Shuffled Complex Evolution (SCE-UA) is used to extract mechanical properties from the measured dispersion spectra cooperating with theoretical model. In the results, surface wave dispersion spectra are measured for three different thickness coatings at different temperature environment. The difference thickness of coatings and temperature environment are reacted to dispersion spectrum of guided waves. It also related to mechanical properties of coating in theoretical model. This method is potentially useful to characterize the mechanical properties of thermal spraying coating in a nondestructive way.
Numerical simulation and experimental study on surface acoustic waves interacting with cracks heated by scanning heating laser source
Authors: Shen Zhonghua , Li Jia , Ni Chenyin , Gusev Vitali
Published: April 2012

The influence on surface acoustic waves (SAWs) propagate through the micro-crack with partial closure is presented in this paper. Heating brought by laser irradiation causes the thermal expansion of the sample, which leads to partial closure of the micro-crack. The partial closure of crack impacts the transmission efficiency of acoustic pulses strongly. Detected SAWs signals are different when heating laser irradiates different regions, when the middle region of the crack is heated, the amplitude of SAWs signals reach the maximum value. Based on this, the experimental system for detecting micro-crack is set up. The crack can be detected effectively by scanning the laser heating source. The finite element method is applied to simulate the temperature rise and relative displacement of crack edges caused by laser irradiation. The relative displacement change with different location of heating laser source is also calculated. The results of numerical simulation and experiment coincide with each other.
Influence of acoustic leakage at liquid-solid interface on the interferometric detecting surface acoustic waves
Authors: Zhao Yan , Shen Zhonghua , Lu Jian , Ni Xiaowu , Cui Yiping
Published: April 2012

Optical interferometry is an important method to detect the surface acoustic wave due to its advantages, such as without contact and a wide responsive bandwidth. So optical interferometric detecting the surface acoustic wave (SAWs) was widely used to diagnosis the surface and subsurface defection, which senses the SAWs by detecting the instantaneous surface displacement on the interfaces. Commonly, the material are placed in air or a special liquid and the surface acoustic wave is leaky and readiates energy into the liquid under the form of bulk waves. As a results, there has another factor to make the interferometric signal change, that is the refractive index variation of liquid induced by the leakage acoustic wave. In this paper, we will mainly analyze the influence of acoustic leakage at liquid-solid interface on the interferometric detecting surface acoustic waves and discuss the suitable condition of ignoring the influence of leakage wave in liquid on interferometric signal to ensure the measuring accuracy of interferometric sensor.
Relative contributions of temporal and spectral cues for Mandarin and Cantonese tone recognition
Authors: Kong Ying-Yee , Lee Tan , Yuan Meng , Yu Wilson
Published: April 2012

Despite good speech perception performance in quiet, pitch perception remains a challenge for cochlear-implant users. The current vocoder-based processing technique in cochlear implants preserves temporal envelope and coarse spectral information. This information, however, is insufficient to support high-level performance for tone perception in tonal languages (e.g., Mandarin and Cantonese), particularly in noise. Mandarin has four lexical tones and Cantonese has six lexical tones. Each lexical tone has different fundamental frequency contours. The temporal envelope of the signal also differs among different tones. In this talk, we will first discuss the relative contributions of temporal and spectral envelope and fine structure cues for Mandarin and Cantonese tone perception. We will then describe a new signal processing algorithm developed at the Chinese University of Hong Kong that aims to enhance temporal periodicity cues for Cantonese tone perception in noise. We will present findings from normal-hearing and cochlear-implant listeners, which demonstrate a significant improvement of Cantonese tone perception in noise with this new algorithm.
Lexical tone development in children with cochlear implants
Authors: Xu Li
Published: April 2012

Most of the languages in the world are tonal. In a tonal language, voice pitch variation (i.e., tone) at the syllable level is a segmental structure that conveys lexical meaning of words. Multichannel cochlear implants (CIs) have shown great success in providing profoundly-deafened individuals with satisfactory speech perception in quiet. However, contemporary speech-processing strategies used in CIs do not explicitly code pitch information. This presentation will be focused on (1) acoustic cues for recognition of lexical tones, primarily the Mandarin Chinese tones, and the relative contributions of various cues to tone recognition, (2) results of tone recognition experiments in implant recipients in relation to their differences in demographics, devices, strategies, and psychoacoustic abilities, (3) relationship between music pitch perception and lexical tone recognition, and (4) results on tone production and vocal singing in prelingually-deafened, native tonal-language speaking children with CIs. It is concluded that there are marked deficits in tone development in tonal-language-speaking children with CIs. Results also indicate that early implantation and experience with using the device help improve tone development in prelingually-deafened tonal-language-speaking children. [Work supported by the NIH/NIDCD.]
Combined electric and acoustic stimulation to improve tonal language processing in cochlear implant users
Authors: Zeng Fan-Gang , Yang Hsin-I
Published: April 2012

A unique characteristic of tonal language processing is the use of multiple acoustic cues that are distributed in both time and frequency domains to achieve robust recognition of tones. The temporal cues can be represented by simple acoustic differences in duration or amplitude contours that are correlated to tonal patterns. The spectral cues can be represented directly by fundamental frequency or indirectly by its harmonics. Because contemporary cochlear implants process only the less salient temporal cues, their users have generally poor tonal processing abilities. The present study takes advantage of residual low-frequency acoustic hearing (e.g., < 500 Hz) that is often present in the cochlear implant users. Although this low-frequency hearing contributes little to speech intelligibility directly, it is sufficient to convey tonal information via fundamental frequency. The present study measures word recognition in noise in a group of Mandarin-speaking cochlear implant users who have significant residual low-frequency acoustic hearing. Preliminary data showed that combined electric and acoustic stimulation significantly improved word recognition in noise. The mechanism for this improvement will be discussed in terms of independent or synergetic contributions from the acoustic and electric cues.