bluuebunny/crossref_metadata_2025 huggingface dataset:
A new composite particle for both contrast-enhanced ultrasound imaging and cell therapy
Authors: Cheng Qian , Tan Qing-Gang , Liu Ying-Bin , Li Song-Gang , Li Mao-Lan , Qian Meng-Lu
Published: April 2012

In this paper, a new composite nano-particle for both contrast-enhanced ultrasound imaging and cell therapy is introduced. The carbon nanotubes are used for carriers due to their unique hollow structure, nano-diameter and good biocompatibility. The targeted protein, the hematoporphyrin and the gold nanoparticles are assembled on the surface of the carbon nanotubes. The targeted protein is used as tumor localization. As a kind of sonosensitizer, the hematoporphyrin can produce the singlet oxygen while being activated by ultrasound and are studied for its effects of antitumor and apoptosis induction recently. It is worthwhile to note that the singlet oxygen has a very short lifetime and will transfer to triplet oxygen with light emission band at 1268 nm, or 634 nm and 703 nm. Triplet oxygen is the ground state of the oxygen molecule and much of them will form nano oxygen bubbles under body temperature which can be used as contrast-enhanced ultrasound imaging agent. At the same time, the gold nanoparticles which have good biocompatibility can absorb the light emission and produce the acoustic signals of some bandwidth. This work is supported by the National Natural Science Foundation of China (No. 10804085, 11174223 and 50603019), and the Shanghai Nano Special Foundation(No. 1052nm05400)
Size-dependent backscatter coefficient from lipid-coated monodisperse microbubbles
Authors: Gong Yanjun , Cabodi Mario , Porter Tyrone
Published: April 2012

In this study, the relationship between backscatter coefficient (BSC) and the size of Ultrasound Contrast Agents (UCAs) microbubbles has been investigated in vitro. Monodisperse lipid-coated microbubbles were produced using a flow-focusing microfluidic device. A single-element unfocused transducer with center frequency 2.25 MHz was used to measure the BSC of microbubbles in the frequency range 1-3 MHz by transmitting 1 cycle broad-band acoustic pulse with a peak-to-negative pressure 35 kPa. When compared to polydisperse microbubble with the same lipid shell composition and concentration, monodisperse microbubbles exhibited a distinct peak in the frequency-dependent BCS curve, which corresponded with the resonance frequency of the monodispersion. Furthermore, the BSC for monodisperse microbubbles was higher than that for polydisperse microbubbles around resonance frequency. This result suggests that a monodispersion driven at resonance will provide greater contrast in ultrasound images than a polydispersion, provided the concentrations are equivalent. Finally, the BSC for five monodispersions with mean diameters of 4.5, 5.1, 5.6, 6.4 and 7.4 μm with the same concentration (5000/ml) was measured and compared. The results showed that the resonance frequency was inversely related and the BSC amplitude was directly proportional to mean diameter. The implications of these results on subharmonic contrast imaging will be discussed.
Acoustic metamaterials by bending layered structures
Authors: Liang Zixian , Li Jensen
Published: April 2012

In this talk, basic concepts of metamaterials for acoustic imaging and wave manipulation using layered structures will be introduced. Starting from periodically layered structures, we can easily construct metamaterials with large anisotropy which is very useful to obtain sub-wavelength resolution in acoustic imaging. By geometric scaling the layered structure in a fixed direction, an acoustic hyperlens can be obtained so that the image with subwavelength details can be progressively magnified and exit the lens as far-fields. We have now further developed different geometric transformations by bending the layered structures to achieve a variety of wave manipulations including negative refraction in the effective medium regime, acoustic cloaking, and tunneling with a density-near-zero material.
Transformation acoustics: virtual pinholes and collimators
Authors: Xu Jun , Jing Yun , Fang Nicholas X.
Published: April 2012

In this invited talk, our preliminary study is presented on a virtual hole and a broadband acoustic collimator, by combination of the concept of complimentary media with transformational acoustics. Such effect is exemplified by a segmental defect in the original cloak, which appears as if a dipole scatterer was under the acoustic imager. A set of spatially varying effective parameter was derived from coordinate transformation. These parameters can be readily implemented using non-resonant acoustic elements. The numerical study confirmed the collimation of acoustic beam from a small hydrophone behind the metamaterial device. The potential application of such novel device concept in underwater communication and medical ultrasound will be also discussed.
New acoustics, based on metamaterial
Authors: Gan Woon Siong
Published: April 2012

With the capability to fabricate acoustical metamaterial:phononic crystals, double negative material and materials with material parameters based on the predetermined direction of sound propagation, one can control and manipulate sound propagation in solids and fluids. This gives rise to new forms of refraction, diffraction and scattering, the three basic mechanisms of sound propagation in solids and fluids.Besides the capability of designing perfect lens based on negative refraction, the coordinates transformation can yield a lens of going beyond linear refraction to the nonlinear case of bending the sound wave to any direction of our choice. A generalized Snell's law based on curvilinear coordinates is derived and possible application given. Refraction between two media of different parities also produces new phenomena which can be utilised in resonators and waveguides. A new rigorous theory of diffraction is formulated based on material parameters enabling the manipulation of diffraction and defeating the diffraction limit. Nonlinear acoustics based on nonlinear phononic crystals is also considered. The behaviour of solitary wave is studied. A new Christoffel equation based on double negative material is also derived.
Making an acoustic sensor undetectable with a pair of single-negative materials
Authors: Xu Tao
Published: April 2012

We have proposed a two-dimensional cylindrical multi-layers device which can make a cylindrical acoustic sensor undetectable when the thickness of each layer of our device is much smaller than the wavelength of the incident wave. Our device only consists of a pair of complementary isotropic single-negative materials instead of double-negative ones. The parameters of materials in the device are homogenous and independent of those of host material as well as the cloaked object. Full wave simulations by finite element method are performed to verify the feasibility of the device. This proposal would greatly reduce the difficulty in both experimental design and fabrication.
The theoretical and experimental analysis of an elastic hyperlens for far-field subwavelength imaging in a plate
Authors: Lee Hyung Jin , Kim Hoe Woong , Kim Yoon Young
Published: April 2012

The hyperlens is a novel imaging device that is capable to overcome the diffraction limit, a fundamental limit due to exponentially-decaying wave components containing subwavelength information. Because a hyperlens converts evanescent waves to propagating waves and magnify them, it can transfer a subwavelength image to the far field beyond the hyperlens. These interesting capabilities can be achieved through an extreme anisotropy in an effective permittivity tensor in optics while in a density tensor in acoustics. The extreme anisotropy in an elastic regime, however, is determined by elastic stiffness rather than density unlike in acoustics. We show, by using the homogenization method, how to evaluate the effective elasticity tensor of an elastic plate hyperlens consisting of alternating layers of metal and air. To experimentally demonstrate far-field subwavelength imaging by the hyperlens, a specially-configured experimental setup is suggested. The ratio of the input power to the output power is investigated both theoretically and experimentally.
Experimental study of backscattering enhancement using acoustic double-positive metamaterials
Authors: Hu Wenlin , Fan Yuxian , Ji Peifeng , Yang Jun
Published: April 2012

Backscattering enhancement can be achieved by superscatterers which magnify the scattering cross section of an object. To realize this kind of scatterers, a posible approach on the conception of complementary media requires double-negative materials which may induce sound absorption. In this paper, a method for backscattering enhancement by using double-positive acoustic metamaterials is presented. A shell with discretely layered metamaterials is coated on the rigid cylinder to enhance the strength of backward scattering. Density and bulk modulus of the metamaterials are both positive and limited in a reasonable range. An experiment of backscattering enhancement is investigated. The layered shell is constructed from the metamaterials employing acoustic transmission line network. The scattering sound fields of the object and the layered structure with the same geometric scale are measured in a parallel plate waveguide. Scattering properties on both backward and forward direction are analyzed from the experimental results and the scattering enhancement effect with positive metamaterials is discussed.
Experiments in phononic crystal plates for negatively-refracted guided shear-horizontal waves by using magnetostrictive patch transducers
Authors: Lee Min Kyung , Ma Pyung Sik , Lee Il Kyu , Kim Hoe Woong , Kim Yoon Young
Published: April 2012

Experiments performed for negatively-refracted bulk shear waves in elastic media have been reported in literature, not for negatively-refracted guided shear waves in a plate. In this work, we present the negatively-refracted guided shear-horizontal wave experiment results in a thin Phononic Crystal (PC) plate. An interesting feature with negative refraction experiments in a plate, compared with those in a bulk medium, is that one can measure full wave field in a nominal base plate as soon as the negatively-refracted wave exists from a PC plate. Therefore, the actual wave path in the nominal plate can be visualized by the present experiment. For successful experiments, among others, the use of proper transducers is important. In particular, pure shear-horizontal wave generating transducers with narrow beam width are preferred. Here, we employed PSA-OPMT's (Planar Solenoid Array Orientation-adjustable Patch-type Magnetostrcitve Transducers) for wave generation and measurement. The negative refraction angle estimated from the experiments is shown to be in good agreement with the theoretically calculated values through Snell's law. For instance, the experimentally-determined refraction angle is -11.35 degree at the frequency of 220 kHz and it differs within 10% from the theoretical value, -12.67 degree.
The current and future development of aircraft noise management measures in Taiwan
Authors: Lu Cherie , Hullah Peter
Published: April 2012

The geographical characteristics of Taiwan have made the country heavily dependent on air transport and this, combined with the island's high population density, has augmented the importance of aircraft noise issues. Nine of the country's seventeen airports are on the main island, with eight being on remote islands. Following the corporatization of Taiwan Taoyuan International Airport, the Taiwanese Civil Aeronautics Administration (CAA) is in charge of sixteen airports, of which six are of joint civil-military use. This paper presents the current aircraft noise management measures at Taiwanese airports: noise limits for aircraft, regulations on the reduction of aircraft noise at source, aircraft noise charges, land use planning of airport neighbourhoods, improvements to airport layouts, and noise monitoring systems. After consideration of various aspects of environmental impacts due to aircraft and airport operations, the CAA has been planning the implementation of an airport environmental management system, using Taipei Songshan Airport, in the heart of the city, as the first pilot case. In addition, having reviewed work done by the international Aircraft Noise Non-Acoustic factors (ANNA) discussion group, the paper suggests methods for handling Taiwan's noise issues in a resident-friendly manner.
Culture specific approaches in music content analysis
Authors: Serra Xavier
Published: April 2012

The extraction of culturally meaningful features from audio recordings of music different from the western repertoires that are the most studied requires new signal analysis techniques and machine learning methods. The fact that many music traditions have fundamental differences from western ones, such as different musical instruments, tuning systems, performance styles, or musical forms, imply that at the level of feature analysis, most of the descriptors and extraction methodologies being used to analyze western music are not appropriate, or at least they have to be developed much further. Culture specific issues have profound research implications, offering new research problems and requiring new approaches. In this article we will present some initial results in the audio content analysis of the classical music traditions of India (Hindustani and Carnatic) and Turkey (Ottoman) especially for the issues of melodic and rhythmic description. This research is being carried out within a large project entitled CompMusic that aims to promote and develop multicultural perspectives in music computing research. In this project we want work on culture specific music problems with the goal to find new computational methodologies of interest for a wide variety of music information processing problems.
Dynamics of the Himalayan singing bowl
Authors: August Brandon , Mahara Aditya , Moore Thomas
Published: April 2012

The singing bowl, commonly known as the Tibetan or Himalayan singing bowl, is an idiophone indigenous to many Asian cultures. Singing bowls are usually made of brass, which is hammered into a nearly symmetrical hemispherical shell and then hand-turned on a lathe. A sound is produced by either striking the bowl or rubbing the surface with an excitation stick referred to as a puja. We report on an investigation of the sound generation mechanism of the singing bowl, with an emphasis on understanding the origin of the sound created by the stick-slip excitation mechanism that occurs while rubbing the bowl with the puja. It is shown that both the radial and tangential motion of the puja experience exponential gain during the excitation process, and the feedback mechanism required to produce this behavior is discussed. A slow oscillation in the sound produced by the bowl is explained by the dominance of a single vibrational mode that rotates at the angular speed of the puja.
Shaping the resonance. Sympathetic strings in Hindustani classical instruments
Authors: Weisser Stephanie , Demoucron Matthias
Published: April 2012

Most chordophones of the contemporary classical Hindustani tradition are characterized by the presence of numerous sympathetic strings taraf (sometimes up to over 30). Generally tuned according to the rag, they are inserted within the handle of the plucked lutes sitar and sarod, and next to and below the main strings of the bowed fiddle sarangi. In some cases (e.g. some of sarangi's, all of them in sitar), taraf are also equipped with a curved bridge, increasing the spectral richness of the sounds produced by these strings. Players consider the taraf's response as fundamental to the instrument's sound. Based on field recordings realized in ITC Sangeet Research Academy (Kolkatta) this study aims to determine the contribution of these strings to the resulting sound of the different instruments and settings. Acoustical analyses are complemented with ethnomusicological analyses, in order to evaluate the taraf's aesthetic, musical and perceptual role.
Outside-instrument coupling of resonance chambers in the New-Ireland friction instrument “Lounuet”
Authors: Bader Rolf
Published: April 2012

The Lounuet is a friction instrument from New Ireland, Papua New Guinea, built from a wooden, round block, about 50 cm long, where three resonance chambers are carved below three lamellas which are played by the bare hand. As the driving mechanism is the same as with the bowed string, a perfect harmonic overtone series is produced showing frequencies up to 25 kHz. Although its fundamental is close to the lowest resonance frequency of the lamellas, the radiation nearly solely comes from the resonance chambers below the lamellas. Using a Microphone Array, back-propagating the radiated sound field to the open wholes of the resonance chambers, for different partials complex radiation patterns appear, showing clear relationships between the three chambers. Most of these standing waves between chambers show a coupling outside of the instrument for frequencies above ~ 600 Hz, where the air between the holes outside the instrument are separate anti-nodes of the standing wave fields. So these outside-instrument air resonance couplings are similar to those known from the Japanese shakuhachi wind instrument which there appear between the highest sound hole and the blowing hole.
Sound power level calculation of industry sources—simulation
Authors: Probst Fabian
Published: April 2012

Modern calculation methods enable the simulation of the sound power level measurement of complex industry sources applying the enveloping surface method. According to this procedure receiver points are created and distributed on spherical or cuboid surfaces following the relevant International Standards like ISO 3744 or ISO 3746 or on cylindrical or other regular surfaces depending on the requirements of any underlying machine specific standard. The sound pressure levels at these receivers on the enveloping surface and the resulting “effective” sound power level is calculated. The comparison of these sound power levels determined by simulation and the sound power levels of the sources in the model shows the influence of the geometric shape of the measuring surface. Such a simulation of the sound power determination with the enveloping surface method is applicable even in cases where a real measurement would not be possible, e. g. if the effective sound power level of a complete power plant or of a city with all its traffic sources shall be determined. The method and some practical examples are demonstrated.
Stabilization of time-domain acoustic boundary element method for sound radiation problems
Authors: Jang Hae-Won , Ih Jeong-Guon
Published: April 2012

Time-domain acoustic solution from the Kirchhoff integral equation for the exterior problem is not unique due to the presence of fictitious internal modes and also suffers from the instability that stems from the time marching scheme. In this work, methods to stabilize the time-domain acoustic boundary element calculation were suggested. Low-order fictitious internal modes within the effective frequency range of boundary element calculation were suppressed by the newly formulated time-domain CHIEF (Combined Helmholtz Integral Equation Formulation) method. Additional interior points were included, similar to frequency-domain problems, to satisfy the zero pressure constraint considering the shortest retarded time between boundary nodes and interior points. However, the calculation was yet unstable due to remaining unstable high-order modes beyond the effective frequency limit. To further stabilize the computation, unstable high-order internal modes were nullified using the wave vector filtering method. In comparison with the time-domain Burton-Miller formulation, the proposed method has no hyper-singular integral and the monotonically increasing instability was not observed. As a test example, sound radiation from a pulsating sphere was used and a good stabilization performance was shown. Average relative-difference norm of the stabilized time response from the analytic solution was 2.7%. (This work was partially supported by BK21 project)
Development of a practical method for determining noise contribution from a large extruded panel using sound intensity method and optimized finite element model
Authors: Shen Anne , Cheng Jiumei , Sui Fusheng
Published: April 2012

A practical method is proposed for determining noise contribution from a large extruded panel to the sound pressure level inside an enclosure based on acoustic measurements and numerical simulations. A finite element model is constructed for a rigid enclosure with one surface replaced with an extruded, curved panel. The interior sound pressure field is optimized using experimentally obtained reverberation time. The vibratory responses and sound intensity of the extruded panel under mechanical excitation are measured and the interior sound pressure levels are recorded. The structural-acoustic sensitivity term of the interior point is determined and used to update the vibroacoustic responses of the finite element model. The optimized numerical model can be used to predict panel noise contribution for any given excitation source.
An efficient time domain solver for the acoustic wave equation
Authors: Mehra Ravish , Raghuvanshi Nikunj , Savioja Lauri , Lin Ming , Manocha Dinesh
Published: April 2012

An efficient numerical solver for time domain solution of the wave equation for the purpose of propagation in small and large acoustic spaces is presented. It is based on the adaptive rectangular decomposition technique that subdivides a space into rectangular partitions and within each partition utilizes the analytical solution of the wave equation for spatially invariant speed of sound. This technique allows numerical computations in kilohertz range for auralization and visualization purposes. This can help engineers to quickly locate geometric features responsible for acoustical defects in practical engineering applications like noise control. It is demonstrated that by carefully mapping all the components of the technique on the GPU architecture, significant improvement in performance can be achieved while maintaining accuracy comparable to a high-order finite difference time domain (FDTD) solver. It is an order of magnitude faster than corresponding CPU-based solver and three orders of magnitude faster than the CPU-based FDTD solver. This technique can perform a 1 s long simulation on complex-shaped 3D scenes of air volume 7500 cu m till 1650 Hz within 18 min on a desktop machine. The ideal session for this work is “Computational Acoustics”.
Acoustic generation of flow past an in-duct baffle
Authors: Chan H. Y. H. , Leung R. C. K. , Choy Y. S.
Published: April 2012

Recent research was carried out to calculate the acoustics generation induced by flow numerically. In this paper, a modified hybrid acoustics/viscous splitting technique was employed in a computational simulation to calculate the acoustic generation when flow passes through a baffle in duct. The acoustics/viscous splitting technique for Computational Aeroacoustics (CAA) was first developed by Hardin and Pope. Traditionally, CAA problems were computed by Direct Numerical Simulation (DNS) to solve the compressible Navier-Stokes equation. However DNS is very expensive in terms of computation power and time consuming. The Hybrid approach is regarded as a alternative of solving the aeroacoustics problem. Perturbation technique is employed to calculate the acoustics perturbation which superimposes with the incompressible solution to obtain the compressible flow solution. In this paper, the hybrid CAA technique was developed and applied in a 2D duct with single baffle.
Aeroacoustic source modeling for the Galbrun equation
Authors: Xue Feng , Mabrouk Ben Tahar
Published: April 2012

A new numerical technique for acoustic noise generation, based on the Galbrun equation is developed. The source term developed is from a calculation of an incompressible flow part. The acoustic equations are obtained from the numerical solution of a system of perturbed, compressible, linear equations, as the Galbrun equation. The Galbrun equation is solved by a high order mixed finite elements method in the frequency domain. Two examples to valid our source model are given. The first example is a pulsating sphere in one dimension. The result is compared with other known approaches. This example is considered as a first validation case of the code. The second example is applied for two co-rotating vortices in two dimensions. The result is compared with an analytic solution.
Experiences in development and maintenance of Silence-GIS
Authors: Hartog van Banda Sven Erwin
Published: April 2012

Silence is a GIS (Geographical Information System) build on ArgGIS 9.3.1. This large scale noise management system has been designed for the Dutch Highway Authorities. The aim of the system is to support decisions on Dutch and European noise policy and to predict the effect of future measures on the noise exposure of the population in The Netherlands. The information needed to perform noise calculations was divided over different departments. There was a great need for standardization and integration of the different data sets. This was maybe the largest challenge of the Silence project. For the development an agile development method was chosen that involved the product owner during all the stages of the development. Terms were introduced like sprints, scrum meetings, back log, burn down charts, pigs and chickens. To keep the system up to date contracts were made between the product owner and the departments that supplied the data. This paper gives insight in the challenges and benefits of Silence, the advantages of an agile development method and gives an overview of the system hardware, the IT infra structure and the geographical database.
Application of Geographic Information Systems to manage and control urban noise
Authors: Stapelfeldt Hardy , Pfäfflin Florian
Published: April 2012

Environmental Acoustic Software products support different levels of interaction with GIS Software packages. Depending on the achieved level of interaction its value in project applications will rise. Different levels are discussed and demonstrated on practical applications: 1. Standard file exchange formats with GIS adaptation matching the needs of the Acoustic Software, e.g. QSI data format according to German DIN 45687 2. Standard file exchange format with object and attribute definition ruled by GIS software 3. Direct data communication, using e.g. geo-database of GIS application 4. “On the Fly” Pre-processing of GIS ruled attribute content ahead of noise calculation 5. Using external DLL's of Acoustic Software to check and update attribute content on GIS level 6. Supplementing GIS ability in initial data refinement by calling specific geometric and attribute manipulation tools of the Acoustic Software. 7. Steering any automated processing of complex workflows Automated workflows have been used in EU conform Noise Mapping for the German States of Nordrhein-Westfalen (~40.000 km2) and Thüringen (~20.000 km2). Both example cases will briefly be lined out.
Noise calculation method for noise mapping—what to do?
Authors: Probst Dr. Wolfgang
Published: April 2012

Lots of investigations have been undertaken to find the best solution how to calculate the noise levels for noise mapping and action planning purposes. Researchers try to model the environment as detailed as possible and to include the observable phenomena like wind, temperature gradients and ground effects with more sophisticated mathematical descriptions. But many of these developments with possible improvements on one side may cause severe problems in final applications. These interdependencies are shown and demonstrated with practical examples and recommendations are given how to treat the transformation of theoretical concepts into generally applicable methodologies.
Study on noise mapping in developing Cities
Authors: Xia Dan , Zhou Yude , Zhu Wenying , Zhang Weichen
Published: April 2012

Nowadays, noise mapping which can quite well reflect a long-term noise value of a particular region has been widely used in many cities. It also has a positive meaning and impact for those developed cities on noise management. But for many Chinese cities such as Shanghai, there are some differences. It is difficult to determine the long-term noise level because of more and more roads and the widely fluctuated traffic in these cities. Normal noise map does not work well any more. To solve this problem, noise mapping should be dynamic. Dynamic noise mapping updates based on the changes of geographic information and traffic flows, and shows the trend of noise level in the region. It is necessary to systematize the noise mapping, including geographic information system, acoustic model system, display system and check system. In this way, the maps can achieve a dynamic output according to the changes of input parameters. Dynamic noise mapping provides an information platform for noise management, which makes noise control measures more targeted and effective. Also, it helps environmental impact assessment in noise prediction. Meanwhile, it shows people noise level around them and enhances public awareness of noise abatement.
Using acoustic microstreaming to improve detection of gene expression in single cells
Authors: Aumann Tim , Boon Wah Chin , Horne Mal , Axelsson Annika , Rosengren Anders , Petkovic-Duran Karolina , Zhu Yonggang , Manasseh Richard
Published: April 2012

Functional heterogeneity among different cells of an organism (brain cell, heart cell etc.) is brought about by expression of different subsets of genes drawn from the same genetic template (DNA). Therefore, to understand the molecular basis of normal (healthy) and abnormal (diseased) cell behavior, one must measure gene expression. The typical procedure is to homogenize large numbers (>1,000) of cells together, isolate the first product of gene expression (RNA), reverse transcribe the RNA to a cDNA copy, then identify and quantify gene-specific cDNAs. Unfortunately, the gene expression profile obtained represents an average across all combined cells and cell behaviors rather than any particular cell. Ideally one would measure gene expression in a single cell; however the very small amount of labile RNA obtainable from a single cell mostly degrades before it can be measured. We have developed an acoustic microstreaming-based device (“micromixer”) which improves mixing of solutions within microliter volumes. Here we show application of “micromixing” to standard laboratory reverse transcription reactions significantly improves conversion of single-cell amounts of RNA to cDNA. Micromixing is therefore a low-cost and easy-to-use technology that is compatible with and can be added to standard laboratory hardware, software, reagents and expertise to enable better gene expression measurement from single cells.
UV epoxy bonding and enhanced SAW transmission for applications in acoustofluidic integration
Authors: Langelier Sean , Yeo Leslie , Friend James
Published: April 2012

Surface acoustic waves (SAWs) are highly attractive as a means of fluidic and particulate manipulation in Lab-on-a-Chip systems. However, standard acoustofluidic fabrication practices rely heavily on the use of elastomeric materials such as PDMS which are inherently ill-suited for conveyance of SAWs as they introduce severe acoustic attenuation. Here, we explore the use of a low-viscosity UV epoxy resin for room temperature bonding of piezoelectric SAW substrates with standard micromachined supersaturates such as Pyrex and Silicon. The bonding methodology is straightforward and allows for reliable production of sub-micron bonds that are capable of enduring the high surface strains and accelerations typical of SAW propagation. Transmission in devices prepared with this approach show as much as 20 dB of improvement compared to devices fabricated using the standard PDMS elastomer. The method is further used in the fabrication of closed-channel SAW pumping concepts for applications in micro-scale flow control.
Formation of two-way Lamb waves and force potential wells using single conventional ultrasonic transducer and sheep horn shaped metal piece
Authors: Wan Yiyang , Zhang Siyuan , Zong Yujin , Wan Mingxi
Published: April 2012

A new method is introduced that uses single conventional ultrasonic transducer and a sheep horn shaped metal piece to induce two-way Lamb waves, and furthermore collects leaky Lamb waves to form two force potential wells. The immersion acoustical measurements show that the two-way Lamb waves with adjustable amplitudes can be induced when a 1MHz transducer radiates ultrasonic waves on to the semicircle of a metal “sheep horn”. Furthermore, the results obtained by hydrophone measurement and fluorescence microscope observation verify that the force potential well can be formed in the circle of metal “sheep horn” by the leaky Lamb wave of each way and possibly used to collect the submicro particles. This designed method is intended to provide assistance in limited space for microscope observing by collecting particles within low force potential well. All experiment results also indicate that radiation force and the gradient of force potential well produced by this leaky Lamb wave device is very small due to several reasons including low generation efficiency at semicircle tip and propagation attenuation of Lamb wave in metal piece, near field properties of leaky Lamb wave in liquid, and so on.
Effects of auditory priming on speech recognition in combination with spatial and fluctuating masker benefits
Authors: Freyman Richard
Published: April 2012

This presentation will discuss research on three individual causes of release from masking in speech recognition as well as the interactions among them. Spatial differences between target and masker produce release from masking through head shadow effects, binaural processing of interaural differences, and, under some specific circumstances, perceived spatial differences between target and masker. A second frequently-studied type of masking release occurs when fluctuations in a masker's amplitude envelope over time create temporal epochs in which speech-to-masker ratios are very favorable. The efficiency of masking is also reduced when a listener's prior knowledge of message content reduces uncertainty about what s/he will hear, a process often called auditory priming. This presentation will describe a series of recent experiments that consider factors that affect auditory priming and fluctuating masker benefit, individually and when combined with spatial cues. [Work supported by NIDCD DC01625.]
Fine-structure storage, correlation computation, attribute capture, perceptual integration, and perceived spatial separation: an auditory chain in the reverberant environment
Authors: Li Liang
Published: April 2012

In a reverberant environment with multiple-people talking, listeners are still able to recognize attended speech to a remarkable degree. The tolerance to disruptive stimuli largely depends on perceptual integration between direct and reflection waves of the target speech, because the perceptual integration facilitates the listener's selective attention to the target. In this presentation I show that under simulated noisy, reverberant conditions, recognition of target speech is not only dependent on the direct-reflection perceptual integration, but also functionally related to the lower-level ability to briefly store low-frequency acoustic fine-structure signals (i.e., auditory primitive memory). It is suggested that the auditory chain from the fast-fading primitive memory to correlation computation, reflection-attribute capture, lead-lag integration, perceived spatial separation between sources, and attention facilitation represents the feature-and-spatial parallel-processing strategy of the auditory system for dealing with input “flooding”. Also, there is an age-related decline in both the auditory primitive memory and the perceptual integration-induced release of speech from masking.
A method to determine the road traffic flows for installing the noise barriers along a surface and viaduct combined highway
Authors: Zhang Jiping , Schomer Paul D. , LI Qun , Chen Fei , Zhou Xilu , Han Xioulong
Published: April 2012

A highway composed of surface and elevated sections opened with very little traffic and without noise barriers along the elevated sections to help meet the relatively stringent noise control targets. However, some noise control measures that were added to the basic design included increased height to the guard barrier, low noise road surface pavement, and green buffer zones. Now authorities wish to determine the traffic flow conditions for which noise barriers would be required on the elevated sections. Of course this result can be determined by iteratively stepping through the variables, but this would take great effort. This paper presents a semi-theoretical semi-empirical method that simplifies the problem. Let K be the difference between noise from surface and elevated sections of the road. The noise level is calculated for the surface sections including such factors as speed, percent buses, percent of traffic at night, and other noise related factors from transportation engineering. Then, the noise level of the elevated sections is estimated from the levels calculated for the surface sections added to K. This estimated level is compared to the noise limit, and from this one can establish the traffic flow which would require noise barriers on the elevated sections.
A new developed method for the vibration analysis of a beam with variable cross section
Authors: Wang Gang , Li Wanyou , Li Wenlong , Lv Binglin
Published: April 2012

In this paper, one method which combined the Improved Fourier series method and Differential Quadrature method (DQM) is firstly introduced to analyze the vibration of a beam with variable cross section. For DQM, the weighting coefficients is traditionally obtained by Lagrange interpolation, which would lead the equation system to be ill-conditioned when points are equidistantly chosen. In this paper, Fourier series with several auxiliary functions is applied to obtain the weighting coefficients which would converge at a fast speed and the more points included, the more accurate would be the results. Application of Fourier series to the DQM would avoid the appearance of the ill-conditioned equation system when the points are chosen equidistantly.
Nonlinear interactions as trigger for chaotic vibrations in a simplified brake system
Authors: Oberst Sebastian , Lai Joseph
Published: April 2012

In automotive disc-brake squeal, much of the focus in the past two decades has been directed to the analysis of a brake system's vibration response in the frequency domain using the complex eigenvalue analysis (CEA) to predict the number of unstable vibration modes. Unfortunately, it is well known that not all predicted unstable vibration modes will lead to squeal and the magnitude of negative damping does not always indicate squeal propensity. In the complex eigenvalue approach, only linearised equilibrium is analysed and non-linear behaviour of the brake system is not taken into account. On the other hand, non-linear (transient) time-domain analysis simulates the dynamic behaviour closer to a real brake system, but is rarely applied as it is computationally expensive and frequency domain analyses are very popular in industry practice. In this paper, a simplified brake system in the form of an isotropic pad-on-disc system is considered. Specifically, the pad motion and a related instability are investigated using a nonlinear finite element time-domain analysis (ABAQUS 6.8-4). The complex eigenvalue method fails to detect in-plane acting pad-mode instabilities which initiate in-plane intermittent out-of-plane impulsive excitation. This excitation leads to intermittent chaotic behaviour of the pad and quasi-periodic out-of-plane disc vibration. If the pad behaves in a turbulent fashion, the disc's out-of-plane motion shows toroidal chaos. This chaotic disc vibration could be the cause of the instantaneous brake squeal described in the literature.
Acoustic radiation of stiffened cylinder with double shells
Authors: Qi Libo
Published: April 2012

This paper is subject to respectively calculate the acoustic radiation curves of stiffened cylinders with single shell and double shells under the two conditions of longitudinal unit force excitation and vertical unit force excitation. The models are applied both sides of the free boundary conditions. Three-dimensional hydroelastic theory is applied to solve the fluid-structure interaction problems. Through analyzing the peak values and their corresponded characteristic modes to obtain the structure key models that mainly contribute to the acoustic radiation. As well to instruct the acoustic optimization design of stiffened structures by comparing the frequency spectrum of acoustic radiation of the two structures. Keywords: acoustic radiation; stiffened cylinders; single shell; double shells
Noise and vibration from railway inclined turnout
Authors: Ho Wilson , Chan Cheuk Yin , Chan Tim , Kwan Richard
Published: April 2012

Railway noise and vibration control at turnouts and the associated groundborne noise and viaduct re-radiated noise are major environmental concerns for railway projects in urban area. For new railway lines in Hong Kong, inclined turnouts are used in mainlines (instead of vertical turnout) for smooth load transfer at turnout, and reduction of noise and vibration from the turnout. According to the practice in the world (Calculation of Railway Noise by Dept of Transport in UK, Transit Noise and Vibration Impact Assessment by Federal Transit Administration in USA, etc.), noise and vibration levels from turnout would be higher than that from normal railway track in the range of 2.5dB to 10dB. According to the practice in Hong Kong, +7dB turnout correction is adopted for airborne noise calculation, and +5dB and +10dB turnout corrections are adopted for groundborne noise calculation for inclined and vertical turnouts respectively. This paper presents noise and vibration measurement results at various setback disances from turnouts and discusses the turnout corrections for various operation conditions.
Producing whole speech events: differential facial stiffness across the labial stops
Authors: Gick Bryan , Francis Naomi , Chiu Chenhao , Stavness Ian , Fels Sidney
Published: April 2012

It has long been assumed that the labial stops (e.g., [p], [b], [m]) are articulatorily identical. However, recent evidence [Abel et al. ISSP, 2011] shows that these labial stops are visually distinct. This distinction could result from differential passive responses to air pressure differences across the stops, or could reflect an active difference in facial muscle activation. An active difference would challenge the simplicity of unidimensional physical target-based speech production models. A pilot study was conducted in which air was blown simultaneously into a speaker's mouth and nose just at the onset of /p/ and /m/ closures. Preliminary results show displacement of the cheeks and lips at /m/ onset, but not at /p/ onset. These results indicate different initial muscular settings for these sounds, presumably to stiffen the face in anticipation of the increased oral air pressure for /p/. Biomechanical simulation using ArtiSynth (www.artisynth.org) confirms that this outcome is consistent with activation of distinct muscle sets across the stops. These findings suggest that speech tasks include aspects of the “whole” event, including aerodynamics, rather than being determined by unimodal spatial targeting.
Vowel onset as a rhythmic marker in Japanese single and geminate stop distinctions
Authors: Hirata Yukari , Lin Carmen
Published: April 2012

Hirata and Whiton (2005) found that the durational ratio of stop closure to a disyllabic word was the best parameter to distinguish singleton and geminate stops in spoken Japanese. However, given that vowel onset has perceptual and psychoacoustic importance as a temporal marker (Kato et al., 2003), the best unit may be from the first vowel onset of the target word to that of the following word in a carrier sentence (= Vword). In this study, 36 target disyllabic pairs including singletons and geminates (e.g. [buka] and [buk:a]) were embedded in the sentence [sokowa ____to jomimasu], spoken by four native Japanese speakers at three rates (Hirata and Whiton, 2005). The duration of Vword (e.g. the beginning of `u' in [buka] to the beginning of `o' in [to]) and of Vc(c) (e.g. `uk' from [buka] and `ukk' from [buk:a]) were measured, and the Vc(c)/Vword ratio was calculated. We examined how accurately this ratio classified singleton and geminate tokens across all rates and speakers. The classification accuracy was found to be 97.3-98.0%. This indicates that the duration of Vc(c) relative to Vword is a stable parameter for quantity distinction, and that the Vc(c) unit may constitute a meaningful rhythmic marker in production.
Acoustic characteristics of coronal fricatives in Seoul Korean
Authors: Chang Charles
Published: April 2012

This study presents a detailed acoustic characterization of the contrast between the two voiceless coronal fricatives of Korean, variously described in the literature as a lenis/fortis or aspirated/fortis contrast. In utterance-initial position, the fricatives were found to differ in centroid frequency, frication duration, aspiration duration, following vowel duration, and several aspects of the following vowel onset, including intensity profile, spectral tilt, and F1 onset. Between-fricative differences varied across vowel environments, and spectral differences in the vowel onset especially were more pronounced for /a/ than for /i, ī, u/. However, differences between the fricatives in ƒ0 onset consistently failed to be found. Taken together, the acoustic data showed that the `non-fortis' fricative resembles both the lenis stops and the aspirated stops of Korean in a principled way: properties related to articulatory tension are similar to those of the lenis stops, while properties related to glottal width are similar to those of the aspirated stops. Given this dual patterning, it is argued that the `non-fortis' fricative is best characterized not in terms of the lenis or aspirated categories for stops, but in terms of a unique representation that is at once both lenis and aspirated.
Articulatory-acoustic relations in Cantonese vowel production
Authors: Lee Wai-Sum , Zee Eric
Published: April 2012

The study investigates the quantal nature of two sets of Cantonese point vowels, the long [i: u:] in CV open syllables and the medium-long [i u] in CVS closed syllables, where S = stop consonant, by determining the articulatory-acoustic relations in the production of the four Cantonese point vowels. It evaluates Stevens' quantal theory (1972, 1989) by analyzing variability in articulation and acoustics of the four Cantonese point vowels. It also tests the sensitivity of formant frequencies of these point vowels to variation in linguo-palatal constriction location and degree of constriction along the vocal tract length. The investigation obtains variations in location and degree of linguo-palatal constriction along the vocal tract length during the point vowels, using EMMA AG500, and it relates the articulatory measurements to the corresponding vowel formant frequencies. Preliminary data show that the acoustic consequences of a shift in forward or backward direction of the constriction away from the target position for the point vowels are non-linear. The results appear to support the quantal nature of vowel production (Stevens, 1972, 1989). Furthermore, similar to the findings reported in Beckman, et al. (1995) formant frequencies are relatively less sensitive to variation in constriction location than degree of constriction.