bluuebunny/crossref_metadata_2025 huggingface dataset:
A speech-perception training tool to improve phonetic transcription
Authors: Padgitt Noelle R. , Munson Benjamin , Carney Edward J.
Published: October 2013

University instruction in phonetics requires students to associate a set of quasialphabetic symbols and diacritics with speech sounds. In the case of narrow phonetic transcription, students are required to associate symbols with sounds that do not function contrastively in the language. This learning task is challenging, given that students must discriminate among different variants of sounds that are not used to convey differences in lexical meaning. Consequently, many students fail to learn phonetic transcription to a level of proficiency needed for practical application (B. Munson and K. N. Brinkman, Am. J. Speech Lang. Path. [2004]). In an effort to improve students’ phonetic transcription skills, a computerized training program was developed to trains students’ discrimination and identification of selected phonetic contrasts. The design of the training tool was based on similar tools that have been used to train phonetic contrasts in second-language learners of English (e.g., A. Bradlow et al., J. Acoust. Soc. Am. 102, 3115 [1997]). It consists of multiple stages (bombardment, discrimination, identification) containing phonetic contrasts that students have identified as particularly difficult to perceive. This presentation will provide a demonstration of the training tool, and will present preliminary data on the efficacy of this tool in improving students’ phonetic transcription abilities.
Visualizing vowel-production mechanism using simple educational tools
Authors: Arai Takayuki
Published: October 2013

To develop intuitive and effective methods for educating Acoustics to students of different ages and from varied backgrounds, Arai [J. Phonetic Soc. Jpn. 5, 31–38, (2001)] replicated Chiba and Kajiyama’s physical models of the human vocal tract as educational tools and verified that the physical models and sound sources, such as an artificial larynx, yield a simple but powerful demonstration of vowel production in the classroom. We have also started exhibiting our models at the Science Museum ‘‘Ru-Ku-Ru’’ in Shizuoka City, Japan. We further extended our model to a lung model as well as several head-shaped models with visible vocal tract to demonstrate the total vowel-production mechanism from phonation to articulation. The lung model imitates the human respiratory system with a diaphragm. In the head-shaped model, the midsaggital cross section is visible from the outside. To adjust the degree of nasopharyngeal coupling, the velum may be rotated. Another head-shaped model with the manipulable tongue position was also developed. Two test results were compared before and after using these physical models, and the educational effectiveness of the models was confirmed. The homepage of the vocal-tract models is available at http://www.splab.ee.sophia.ac.jp/Vocal—Tract—Model/index-e.htm. [Work supported by KAKENHI (17500603).]
Demonstrations with Jon Barber, Dan Dahlberg, Jack Netland and Hank Ryan
Authors:   Univ. of Minnesota, Inst. of Technology, Minneapolis, MN 55455
Published: October 2013

Physics is Fun. If that sounds like an oxymoron to you, accept an invitation to see these demonstrations by the University of Minnesota’s The Physics Force. The Physics Force performs the Physics Circus a dozen times a year. The Circus can best be described as a ‘‘Mega-Circus’’ considering the size of the equipment, the amount of humor, and the rapid pace. This demonstration team of award winning physics teachers has performed widely to international acclaim. Although constraints will limit the ‘‘Mega’’ equipment for this performance, the humor and rapid pace will be present in a special performance with an emphasis on acoustics.
Rotating rake turbofan duct mode measurement system
Authors: Sutliff Daniel. L.
Published: October 2013

An experimental measurement system was developed and implemented by the NASA Glenn Research Center in the 1990s to measure turbofan duct acoustic modes. The system is a continuously rotating radial microphone rake that is inserted into the duct. This rotating rake provides a complete map of the acoustic duct modes present in a ducted fan and has been used on a variety of test articles: from a low-speed, concept test rig, to a full-scale production turbofan engine. The rotating rake has been critical in developing and evaluating a number of noise reduction concepts as well as providing experimental databases for verification of several aero-acoustic codes.
Source localization for active control of turbofan rotor-stator broadband noise
Authors: Walker Bruce E.
Published: October 2013

In order to identify a reference signal source for an active noise cancellation system, cross-correlation techniques were used to localize broadband noise source regions on exit guide vanes of the NASA Glenn Research Center Advance Noise Control Fan (ANCF). Arrays of surface pressure sensors were imbedded in one guide vane and in the wall of the fan. Synchronous sampling was used with a multichannel data acquisition system to allow removal of periodic components from the signals. The signals were then cross-correlated to assess radiation directivity and the relationship between vane surface pressure and in-duct acoustic noise. The results of these measurements indicated that broadband unsteady pressures near the leading edge tip of the guide vane were well enough correlated with acoustic radiation that 2–3 dB active noise cancellation could be achieved using a simple gain-delay control algorithm and actuator array. After successful simulation in a wind tunnel environment the concept was incorporated on 15 guide vanes and tested in ANCF. Cross-correlation measurements were further used to evaluate system performance and to identify competing noises from rotating and stationary sources within the fan.
Modal decomposition method for high-frequency acoustic impedance testing
Authors: Schultz Todd , Cattafesta Louis , Sheplak Mark
Published: October 2013

Accurate duct acoustic propagation models are required to characterize and reduce aircraft engine noise. These models ultimately rely on measurements of acoustic impedance for candidate materials used in engine nacelle liners. This paper seeks to increase the frequency range of acoustic impedance testing by extending the standard two-microphone method (TMM), which is limited in bandwidth to ranges where only plane waves propagate, to include higher-order modes. The modal decomposition method (MDM) presented includes the first four normal modes in the model of the sound field and thus increases the frequency range from 6.7 to 13.5 kHz for a 2.54- by 2.54-cm waveguide. To resolve both the incident and reflected amplitudes of the first four modes, eight microphone measurements are required. This paper formulates and simulates the MDM and applies it to measurement of the reflection coefficient for various specimens over the tested frequency range of 0.2 to 13 kHz. Mode scattering, predominately from the plane-wave mode into other modes, is revealed. The experimental uncertainty of the method is discussed.
Analytic, numerical and experimental techniques to formulate four-pole matrices for hybrid system modeling
Authors: Kadam Prasad , Kim Jay
Published: October 2013

Four-pole matrix is a very convenient concept in modeling composite acoustic systems; however, its application has been largely limited to the systems composed of one-dimensional and lumped parameter components as four poles are defined in terms of the acoustic quantities at points. In this work, four-pole parameters of a three-dimensional rectangular cavity are formulated by analytical, numerical and experimental methods according to a general procedure that utilizes the pressure response functions. Results from three methods are compared and confirmed to be very close to one another, which validates the procedure. Therefore, the technique allows formulating the equation of a complex acoustics system by assembling sub-system equations obtained by applying any method, experimental, analytical or numerical, most suitable to modeling the sub system. Some practical issues that arise in the modeling process such as source modeling, convergence problems and measurement techniques are explained. The procedure developed in this work enables modeling of practically any acoustic system, regardless of its size, shape, and complexity, as long as the system has definable input and output ports.
A case study comparing 1-D and 3-D analytical modeling methods for vehicle intake system design
Authors: Aubert Allan C. , Green Ed , Bastiaan Jennifer , Leclercq Thomas
Published: October 2013

There is intense competition among automakers to create ever-quieter vehicles and powertrains. Exterior and interior noise of many vehicles is significantly influenced by noise coming from the engine intake system. In order to address this source, significant effort needs to be expended on the noise design of an engine’s intake system. Cost and time constraints tend to make intake designers ignore many complexities in their modeling efforts, specifically in assuming rigid walls, and using 1D model methods. This paper, presents a case study comparing results for a particular intake system between a 1D model, the 3-D boundary element analysis (BEA) method, both coupled and uncoupled to the structure and the new ACTRAN code by fft/MSC of analyzing coupled structure/fluid systems. The structure accuracy of the result is compared to measurements of a physical prototype. Costs and time required are compared, as well as some of the modeling issues encountered and the relative accuracy of each method.
Determination of shell-radiated noise of an automotive engine air intake system using numerical and experimental techniques
Authors: Moenssen D. J.
Published: October 2013

Automotive engine air intake noise affects the quality of the total vehicle sound. The degree to which engine air intake noise contributes to the total vehicle sound is controlled by the relative contributions of the airborne, structure-borne, and shell-radiated noise components. Proper tuning of intake noise requires an understanding of how each of these noise sources is generated. In addition, accurate methods for modeling and measuring each noise source are required for efficient development of an acoustically tuned engine air intake system. This paper describes a numerical method that simulates shell-radiated noise due to the coupling between the internal pressure pulsations of an engine air intake system and the structural properties of the intake system. Techniques for tuning the acoustic and structural properties of the numerical models are illustrated. In addition, a hybrid-experimental technique for accurate measurement of shell-radiated noise is proposed. The hybrid measurement technique is also used for further validation of the numerical method. The numerical and experimental techniques are designed to determine the shell noise of vibrating components in the presence of background noise, as is typically the case for engine air intake systems. A duct and sidebranch Helmholtz resonator is used to validate both methods.
Structural and acoustic noise radiated by compact disk drives
Authors: Nijhof M. J. J. , Wijnant Y. H. , de Boer A. , Beltman W. M.
Published: October 2013

Optical drives inside PCs typically operate at high speed, which may result in significant noise. These drives function both as airborne and structural vibration sources. Three main paths can be distinguished through which noise is emitted to the surroundings: (1) the vibrations of the front of the optical drive emit noise directly into the far field, (2) the sound waves induced by the vibrations of the faces of the optical drives inside the enclosure excites the enclosure, and (3) the structural path from the mounting points of the optical drive to the enclosure. The techniques used to determine the contribution of each path are described and the results of an experimental setup are presented in this paper. The contribution of the structural path is determined by comparing the results of a normal setup with the result of a setup for which the structural path is eliminated by mounting the CD drive on a support that is structurally uncoupled from the PC. Direct measurements of the pressure with a scanning microphone were made. Also, a reconstruction of the pressure field using the boundary element method based on the measured surface velocities of the main radiating surfaces was made.
Radiated noise from structural vibrations of a PC
Authors: Beltman Willem M.
Published: October 2013

Computer systems typically contain several noise sources like fans, hard drives, and optical drives. The noise emission of these devices can be characterized on the component level, for example with sound power measurements. For fans, the backpressure effect due to chassis airflow impedance can be characterized to capture an installation effect. However, the induced vibration levels and resulting radiated structural noise when sources are placed in a system are less well understood. This paper focuses on a quantification of the radiated noise from enclosure vibrations due to vibration of a source. The surface acceleration distribution on the enclosure panels was measured. This measured vibration pattern was then used to calculate the radiated noise with several models: the Rayleigh integral model, the radiation mode model, and finally a boundary element model. The panel radiation noise was compared to the measured total noise level. This allowed a quantification of the enclosure vibration noise contribution. The results indicated significant contributions at the rotational frequency and its harmonics. The chassis enclosure resonances were apparent.
Critical assessment of indoor noise propagation and prediction in power plants
Authors: Brittain Frank H.
Published: October 2013

Accurate prediction of indoor noise propagation in power plants is important to help estimate occupational noise exposures, and to help predict community noise radiated by plant walls—from levels predicted just inside of each wall. Unfortunately, the basic theories of room acoustics are not applicable. Most power plant rooms are both too large, and too odd shaped for basic room theory, including the Sabine and Norris-Erying theories, to be applicable. Even more important, basic room theory requires empty rooms, and power plant spaces are densely packed with equipment, piping, cable trays, etc. (called fittings). This paper reviews basic room theory, and outlines deficiencies for use in predicting noise propagation inside power plant buildings. Examples are given of walk-away measurements showing that there is no reverberant field, and that reverberation measurements do not correlate well with walk-away test data. Using measurements as an alternative to levels predicted just inside of plant walls to help predict community noise radiated by each wall are discussed. Software for predicting noise in industrial spaces is identified, and their suitability for power plants, which have unusually high fitting densities, is also discussed.
Study of noise transmission from an air compressor
Authors: Nathak Subhro , Puranik Anand , Schut Jeffrey , Wells Lee , Rao M.D.
Published: October 2013

The paper discusses the reduction of noise from a Porter Cable 4-gal, 135-psi air compressor. The objectives were to identify the major sources of noise, implement possible noise control measures, and evaluate their effectiveness. Sound measurements were taken according to a procedure that was developed and based on the standards for power tools. Broadband analysis (1/12 octave band) was done to determine the main sources of noise. Ranking of noise sources was done accordingly. The major source of noise was determined to be the piston cylinder assembly and efforts were taken to reduce this main source of noise. The noise control treatments included manufacturing of new parts, use of gasket made of cork between the housing and the cylinder sleeve to isolate the vibrations, implementing a silencer at the exhaust side of the piston and finally, an enclosure encircling the piston/cylinder assembly. The sound-pressure level measurements of the prototype were compared to the baseline measurements to test the effectiveness of the treatments. The overall sound pressure level was reduced from 101.5 to 94.3 dB with the implementation of enclosure around the piston/cylinder assembly and the silencer at the exhaust side of the piston.
Statistical energy analyis of a scroll compressor using Auto SEA and SEAM software
Authors: Yu Zheng , Rockwood William B. , Sanderson Michael , Blanchet Denis
Published: October 2013

Vibration and internal pressure pulsation propagation in a scroll compressor were modeled using AutoSEA and SEAM software. It was found that the two programs predict very similar results in terms of total dBA levels for the six design alternatives evaluated under three different excitations. In general, however, AutoSEA tended to predict slightly lower responses than SEAM. The main reason for the discrepancy is believed to be differences in how each code treats systems with low modal density. Some appreciable differences were also found for the response level at the bottom of the compressor under certain excitations. Investigation into the cause(s) for that discrepancy in ongoing.
Statistical energy analysis for a compact refrigeration compressor
Authors: Lim Ji Min , Bolton J. Stuart , Park Sung-Un , Hwang Seon-Woong
Published: October 2013

Traditionally the prediction of the vibrational energy level of the components in a compressor is accomplished by using a deterministic model such as a finite element model. While a deterministic approach requires much detail and computational time for a complete dynamic analysis, statistical energy analysis (SEA) requires much less information and computing time. All of these benefits can be obtained by using data averaged over the frequency and spatial domains instead of the direct use of deterministic data. In this paper, SEA will be applied to a compact refrigeration compressor for the prediction of dynamic behavior of each subsystem. Since the compressor used in this application is compact and stiff, the modal densities of its various components are low, especially in the low frequency ranges, and most energy transfers in these ranges are achieved through the indirect coupling paths instead of via direct coupling. For this reason, experimental SEA (ESEA), a good tool for the consideration of the indirect coupling, was used to derive an SEA formulation. Direct comparison of SEA results and experimental data for an operating compressor will be introduced. The power transfer path analysis at certain frequencies made possible by using SEA will be also described to show the advantage of SEA in this application.
Advanced simulation noise model for modern fighter aircraft
Authors: Ikelheimer Bruce
Published: October 2013

NoiseMap currently represents the state of the art for military airfield noise analysis. While this model is sufficient for the current fleet of aircraft, it has limits in its capability to model the new generation of fighter aircraft like the JSF and the F-22. These aircraft’s high-powered engines produce noise with significant nonlinear content. Combining this with their ability to vector the thrust means they have noise characteristics that are outside of the basic modeling assumptions of the currently available noise models. Wyle Laboratories, Penn State University, and University of Alabama are in the process of developing a new noise propagation model for the Strategic Environmental Research and Development Program. Source characterization will be through complete spheres (or hemispheres if there is not sufficient data) for each aircraft state (including thrust vector angles). Fixed and rotor wing aircraft will be included. Broadband, narrowband, and pure tone propagation will be included. The model will account for complex terrain and weather effects, as well as the effects of nonlinear propagation. It will be a complete model capable of handling a range of noise sources from small subsonic general aviation aircraft to the latest fighter aircraft like the JSF.
Prediction of psychoacoustic parameters
Authors: Genuit Klaus , Fiebig Andre
Published: October 2013

Noise is defined as an audible sound which either disturbs the silence, or an intentional sound that listening to leads to annoyance. Thus, it is clearly defined that the assignment of noise cannot be reduced to simple determining objective parameters like the A-weighted SPL. The question whether a sound is judged as noise can only be answered after the transformation from the sound event into an hearing event has been accomplished. The evaluation of noise depends on the physical characteristics of the sound event, on the psychoacoustical features of the human ear as well as on the psychological aspects of men. The subjectively felt noise quality depends not only on the A-weighted sound-pressure level, but also on other psychoacoustical parameters such as loudness, roughness, sharpness, etc. The known methods for the prediction of the spatial A-weighted SPL distribution in dependence on the propagation are not suitable to predict psychoacoustic parameters in an adequate way. Especially, the roughness provoked by modulation or the sharpness generated by an accumulation of high, frequent sound energy cannot offhandedly be predicted as distance dependent.
Processing ultrasound backscatter to monitor high-intensity focused ultrasound (HIFU) therapy
Authors: Kaczkowski Peter J. , Anand Ajay , Bailey Michael R.
Published: October 2013

The development of new noninvasive surgical methods such as HIFU for the treatment of cancer and internal bleeding requires simultaneous development of new sensing approaches to guide, monitor, and assess the therapy. Ultrasound imaging using echo amplitude has long been used to map tissue morphology for diagnostic interpretation by the clinician. New quantitative ultrasonic methods that rely on amplitude and phase processing for tissue characterization are being developed for monitoring of ablative therapy. We have been developing the use of full wave ultrasound backscattering for real-time temperature estimation, and to image changes in tissue backscatter spectrum as therapy progresses. Both approaches rely on differential processing of the backscatter signal in time, and precise measurement of phase differences. Noise and artifacts from motion and nonstationary speckle statistics are addressed by constraining inversions for tissue parameters with physical models. We present results of HIFU experiments with static point and scanned HIFU exposures in which temperature rise can be accurately mapped using a new heat transfer equation (HTE) model-constrained inverse approach. We also present results of a recently developed spectral imaging method that elucidates microbubble-mediated nonlinearity not visible as a change in backscatter amplitude. [Work supported by Army MRMC.]
Ultrasonic characterization of soft tissue vibrations based on the two-dimensional Fourier transform
Authors: Sikdar Siddhartha , Kim Yongmin , Beach Kirk W.
Published: October 2013

It has recently been demonstrated that soft tissue vibrations in the body, traditionally associated with vascular bruits and cardiac murmurs, can potentially be used for the ultrasonic diagnosis of coronary artery disease and vascular trauma. In this paper, the ultrasonic spectrum of soft tissue vibrations is formulated using the two-dimensional Fourier transform, making full use of the information present in the backscattered ultrasound echoes from vibrating tissue. Parametric simulation studies show that vibrations with amplitude 1 μm may be detected even with tissue velocity of 20 cm/s and acceleration of 5 m/s2, e.g., during peak cardiac motion. Vibrations with amplitude as low as 0.1 μm may be detected when the tissue acceleration is negligible, e.g., during mid-diastole. Also, it was found that tissue vibrations in a direction transverse to the ultrasound beam can be detected. In vivo examples of cardiac wall vibrations in patients with coronary artery disease are presented. Tissue vibrations can provide improved sensitivity over conventional duplex ultrasound since the scattering strength from tissue is significantly higher than that from blood. In addition, detection of tissue vibrations has reduced angle dependency and does not require visualization of the vessel lumen, making the exam less dependent on operator skill.
On the diffusion of sound in an auditorium
Authors: Harris Cyril M.
Published: October 2013

A condition of perfect diffusion of sound is said to exist in an auditorium if, at any point within it, the reverberant sound travels in all directions with equal probability, and if the level of the reflected sound is everywhere equal. In deriving the reverberation time formula, which predicts how long sound will bounce around an enclosed space after the source has stopped, W.C. Sabine assumed perfect diffusion within it. When this is not the case, his formula may predict inaccurate results. For example, the Sabine equation will not give correct results in an auditorium with poor diffusion, as when there is a large overhanging balcony, or if one of the dimensions of the enclosed space is very much greater than the other dimensions, or if the auditorium is divided into spaces having different acoustical properties. An auditorium with excellent diffusion beneficially affects the uniformity of decay of sound within the space and pleases the listener’s ear. Among techniques that contribute to good diffusion are the surface irregularities found in the elaborate styles of architecture of the past. Illustrations will be presented showing some approaches within the modern architectural idiom that have yielded successful results.
Hyperechogenicity during high intensity focused ultrasound (HIFU)
Authors: Crum Lawrence , Bailey Michael , Rabkin Brian , Khokhlova Vera , Vaezy Shahram
Published: October 2013

Ultrasound guidance of HIFU therapy is attractive because of its portability, low cost, real-time image processing, simple integration with HIFU instruments, and the extensive availability of diagnostic ultrasound; however, the use of ultrasound visualization for the guidance and monitoring of HIFU therapy often relies on the appearance of a hyperechoic region in the ultrasound image. It is often assumed that the formation of a hyperechoic region at the HIFU treatment site results from bubble activity generated during HIFU exposure. However, it has been determined that this region can be generated with relatively short bursts of HIFU (on the order of 30 ms), bursts so short that negligible temperature elevations are expected to occur. In examining the histology associated with these hyperechoes, there is little evidence of traditional cavitation damage; rather, it appears as if there are many bubbles generated within the individuals cells, suggesting a thermal mechanism. Thermocouple measurements of the temperature elevation were inaccurate due to the short insonation period, but showed only a few-degree temperature rise. These anomalous results will be presented, along with additional data on HIFU hyperechogenicity, and a hypothesis given for the phenomenological origins of this effect. [Work supported in part by the NSBRI, U.S. Army, and the NIH.]
Reproducibility of hemorrhage near fetal rat bone: Preliminary results
Authors: Bigelow Timothy A. , Miller Rita J. , Blue James P. , O’Brien William D.
Published: October 2013

The reproducibility of ultrasound-induced hemorrhage near the fetal rat skull is important in therapy and related bioeffect studies. A 0.92-MHz f/1 spherically focused transducer (5.1-cm focal length) was used to expose the skull of 18- to 19-day-gestation exteriorized rat fetuses (9.6−μs pulse duration). The fetuses were exposed to one of four exposure conditions (denoted A, B, C, and D) in addition to a sham exposure. Three of the exposures consisted of a peak compressional pressure of 10 MPa, a peak rarefactional pressure of 6.7 MPa, and PRFs of 100 Hz (A), 250 Hz (B), and 500 Hz (C), corresponding to time-average intensities of 1.9, 4.7, and 9.4 W/cm2, respectively. Exposure D consisted of a peak compressional pressure of 6.7 MPa, a peak rarefactional pressure of 5.0 MPa, and a PRF of 500 Hz corresponding to a time-average intensity of 4.6 W/cm2. The hemorrhage sizes were 1.4±0.7 mm2 for A (occurrence of 15). a)Currently at Electrical Engineering Department, University of North Dakota, Grand Forks, ND 58202.
Detection of tissue coagulation by ultrasonic displacement map
Authors: Umemura Shin-ichiro , Azuma Takashi , Sasaki Kazuaki , Kawabata Ken-ichi
Published: October 2013

Real-time detection of tissue coagulation before boiling will significantly reduce the current limitation and the potential problems of non-invasive treatment with high-intensity focused ultrasound (HIFU). First, the throughput of the treatment will be doubled because the ultrasonic energy required to heat tissue to its coagulation temperature is about half of that to its boiling temperature. Second, the safety of the treatment will be enhanced because the explosive boiling of tissue can be avoided thereby. Coagulation of tissue can be detected through ultrasonically mapping its displacement. Thermal denaturation of protein is normally accompanied by a slight increase in its volume caused by breakage of hydrogen bonds. This volume change induces small displacement, which can be detected with ultrasound. This volume change as well as change in speed of sound may produce change in acoustic impedance of tissue, which can increase the reflectivity of the coagulated tissue and the acoustic radiation force on it. In vivo as well as ex vivo experiments were performed in combination with HIFU exposures with normal single spot focusing and split focusing. The former effect was dominant with split focusing while the latter was with single spot focusing. These will be discussed in the presentation.
MRI-guided therapeutic ultrasound: Temperature feedback control for extracorporeal and endoluminal applicators
Authors: Salomir Rares
Published: October 2013

Therapeutic ultrasound is a mini-invasive and promising tool for in situ ablation of non-resectable tumors in uterus, breast, esophagus, kidney, liver, etc. Extracorporeal, endoluminal, and interstitial applicators have been successfully tested to date. Magnetic resonance imaging (MRI) is the only available technique providing non-invasive temperature mapping, together with excellent contrast of soft tissue. Coupling of these two technologies offers the advantage of both: (1) on line spatial guidance to the target region, and (2) thermal dose control during the treatment. This talk will provide an overview of the author’s experience with automatic, active feedback control of the temperature evolution in tissues, which has been demonstrated with MRI compatible extracorporeal transducers (focused beam) or endoluminal applicators (plane waves). The feedback loop is based on fast switching capabilities of the driving electronics and real time data transfer out of the MR scanner. Precision of temperature control was typically better than 1°C. This approach is expected to improve the efficacy of the treatment (complete tumor ablation) and the thermal security of the critical regions crossed by the acoustic beam. It also permits one to reach an under-lethal heating regime for local drug delivery using thermosensitive liposomes or gene expression control based on hsp promoters.
Active ultrasonic imaging methods for lesion visualization
Authors: Shrestha Ajay , Otteson Brett , Yao Hui , Ebbini Emad
Published: October 2013

Several transient and irreversible changes in thermal and mechanical tissue properties are known to occur during lesion formation using HIFU. Increase in tissue absorption, decrease in tissue perfusion, and increase in tissue hardness are all associated with tissue necrosis associated with the application of HIFU at sufficiently high dosage. We have apparatus and algorithms for estimation of these tissue properties before, during, and after lesion formation using HIFU. Imaging data are obtained synchronously with the application of HIFU and processed for tissue property measurement. Absorption rate, shear elastic modulus, and perfusion are measured by application of 1 HIFU pulse of duration 0.1 to 0.2 s and sub-therapeutic intensity levels. The HIFU beam is interrupted for collection of imaging lines to obtain a spatio-temporal displacement map with sufficient temporal resolution for viscoelastic tissue property measurements. A description of the imaging system and synchronization between the HIFU and imaging transducers is given. Data from lesion formation experiments in vitro and in vivo are given and discussed.
Acts of Sound: Hands-On Workshop for High School Students
Authors: Keolian Robert , Loubeau Alexandra , Poese Matthew E. , Clark Linde J. , Hansen Uwe J. , Morrison Andrew , Korman Murray S. , Tucholski Edward
Published: October 2013

The Committee on Education in Acoustics is proud to present a workshop for high school students from the Minneapolis public schools. The theme of mentorship will be developed throughout the program. The eight mentors have individually developed their own workstations to inspire, challenge and delight a student’s imagination about sound. The students will split into eight groups of three and work for 30 minutes at their own stations. After initial guidance, the students will do hands-on experiments, take data and try to come up with their own discoveries. Next, students have 15 minutes to prepare impromptu drawings and transparencies for a ‘‘team’’ presentation. Each team will be given 5 minutes to present at their workstation. A mini-cam and projector will be used to zoom in. During refreshments, there will be time for feedback and a musical skit. Then students may walk around to all the other stations to meet the other mentors and do more hands-on experiments at their own pace, as time permits. [Special thanks go to James Bickel, the science curriculum coordinator for the Minneapolis public schools, all the students and their teachers.]
The application of nearfield acoustical holography in the visualization of sound fields in enclosed spaces associated with patches on the surface of the space
Authors: Burroughs Courtney B.
Published: October 2013

A description of the application of nearfield acoustical holography in the visualization of the acoustic fields produced inside an enclosure by sections or patches of the vibrating surface of the enclosure are described. An array conformal to the surface that covers the patch of interest is used to measure the nearfield unsteady complex pressures. These pressures are used with nearfield freefield Greens functions to reconstruct the velocities on the surface under the array. Farfield Greens functions for the enclosed space are the applied to the reconstructed surface velocities to visualize the acoustic field inside the enclosure produced by the surface under the array. A mathematical simulation of the backward propagation to the surface and forward propagation to points inside the enclosure is used to explore the sensitivity of the process to (1) simulated extension of the array to improve resolution, (2) noise, and (3) measurement errors.
Acoustic sources’ localization in presence of reverberation
Authors: Julliard E. , Pauzin S. , Simon F. , Biron D.
Published: October 2013

For several years, aeronautical industries have wished to improve internal acoustical comfort. In order to make it, they need metrological tools which are able to help them to spot acoustical sources and the associated path in a specific frequency range (i.e., for helicopters’ internal noise: 1000–5000 Hz). Two major source’ localization’ tools exist: holography and beamforming, but these two techniques are based on a free field’s hypothesis. So, problems appear when these techniques are used in a reverberant medium. This paper deals with the study and the comparison of holography and beamforming results in an enclosed area. To complete the study, intensimetry is also implemented to have information on the energy propagation. In order to test the performances of each method, two reflecting panels are put at right angles to create a reverberant environment, in an anechoic chamber. We seek to locate loudspeakers clamped in one panel, in the presence of parasite loudspeakers located on the other one. Then, a parametrical study is led: localization and number of sources, coherent or noncoherent sources. Thus, using limitations, precautions to take, and a base of comparison three methods are put forward. Finally, some envisaged solutions to limit problems of reflections (signal processing, overturning, etc.) are presented.
The acoustical design of vehicles: A new tool for benchmarking and target sound
Authors: Genuit Klaus , Schulte-Fortkamp Brigitte
Published: October 2013

Evaluating sound quality leads to difficulties. Conventional tests neglect the context-sensitivity of human perception evaluation; they only reflect artificial realities which do not correspond with perceptual authenticity. Since the subjective evaluation is influenced by different modifiers, it is necessary to extend methods in order to be able to survey and represent various objective variables as well as subjective variables sufficiently. It is known that experiments in laboratories only constitute artificial realities and disregard important parameters like context, relevance, or external validity. The test design lacks the consideration of the usual interaction between the self-stimulated sound and the driver as well as the context, in which the driver experiences and evaluates the perceived sound. A 3-D sound simulation system (H3S) has been developed for the realistic reproduction of airborne sound in driving simulators. Mobile H3S is capable of simulating a vehicle soundscape—consisting of engine sound, tire, and wind noise—according to a real driving situation. A vehicle equipped with this interactive technique can be driven regularly on the road while the acoustic impression for the driver originates from a different or modified vehicle. The soundscape adapts online to changes in speed, engine rpm, and load caused by the vehicle controls.
Noise control, sound, and the vehicle design process
Authors: Donavan Paul
Published: October 2013

For many products, noise and sound are viewed as necessary evils that need to be dealt with in order to bring the product successfully to market. They are generally not product ‘‘exciters’’ although some vehicle manufacturers do tune and advertise specific sounds to enhance the perception of their products. In this paper, influencing the design process for the ‘‘evils,’’ such as wind noise and road noise, are considered in more detail. There are three ingredients to successfully dealing with the evils in the design process. The first of these is knowing how excesses in noise effects the end customer in a tangible manner and how that effects customer satisfaction and ultimately sells. The second is having and delivering the knowledge of what is required of the design to achieve a satisfactory or even better level of noise performance. The third ingredient is having the commitment of the designers to incorporate the knowledge into their part, subsystem or system. In this paper, the elements of each of these ingredients are discussed in some detail and the attributes of a successful design process are enumerated.
NASA Glenn Research Center Acoustical Testing Laboratory: Five year retrospective
Authors: Cooper Beth A. , Akers James C. , Passe Paul J.
Published: October 2013

In the five years since the NASA Glenn Research Center Acoustical Testing Laboratory (ATL) opened its doors in September, 2000, it has developed a comprehensive array of services and products that support hearing conservation goals within NASA and industry. The ATL provides acoustic emission testing and noise control engineering services for a variety of specialized customers, particularly developers of equipment and science experiments manifested for NASA’s manned space missions. The ATL aggressively supports the vision of a low-noise on-orbit environment, which facilitates mission success as well as crew health, safety, and comfort. In concert with these goals, the ATL also produces and distributes free educational resources and low-noise advocacy tools for hearing conservation education and awareness. Among these are two compact discs of auditory demonstrations (of phenomena in acoustics, hearing conservation, and communication), and presentations, software packages, and other educational materials for use by engineers, audiologists, and other hearing conservation stakeholders. This presentation will highlight ATL’s construction, history, technical capabilities, and current projects and will feature demonstrations of some of the unique educational resource materials that are distributed by the ATL.
Federal actions on control noise from airport operation
Authors: Harris Andrew S.
Published: October 2013

The problem of aircraft noise impacts in communities from the operation of airports is addressed from two perspectives: federal actions to establish mechanisms to control noise and actions by airport proprietors to develop noise control programs. Aircraft noise from the operation of civil airports became a community problem with the introduction of first-generation passenger jets such as the Boeing 707 and the Douglas DC-8. Federal Aviation Regulation Part 36 set source limits for new jet aircraft. However, there was no broadly accepted information about the compatibility of environmental noise and community activities and no uniform method to reduce impacts of aircraft noise until further federal action. The U.S. EPA published compatibility information under mandates of the Noise Control Act of 1972 (NCA72). The Federal Aviation Administration promulgated procedures for development and implementation of Noise Compatibility Programs for Airports as Federal Aviation Regulation Part 150 (FAR Part 150) in 1981. The effectiveness of programs developed by airport proprietors under FAR Part 150 is addressed as are the reactions of aircraft operators to concerns that airport programs could adversely impact their ability to conduct business. Congressional actions to limit actions by airport proprietors are also considered as are current regulatory issues.
Error of estimation of community reaction to aircraft noise
Authors: Fidell Sanford
Published: October 2013

Errors and uncertainties of measurement, estimation, and prediction of aircraft noise exposure and of community reaction to it can be so great as to render dosage-effect analyses of community response to aircraft noise unreliable. Biases and other errors may arise during routine monitoring of aircraft noise, via oversimplification and misrepresentation of exposure and sound propagation conditions in predictive noise modeling, through sampling and interviewing procedures, and from poor statistical association in functional relationships between community response and acoustic predictor variables. Some of the more notable uncertainties afflicting the prediction of aircraft noise and its effects are described in this presentation.
Passive interior noise reduction analysis of King Air 350 turboprop aircraft using boundary element method/finite element method (BEM/FEM)
Authors: Dandaroy Indranil , Vondracek Joseph , Hund Ron , Hartley Dayton
Published: October 2013

The objective of this study was to develop a vibro-acoustic computational model of the Raytheon King Air 350 turboprop aircraft with an intent to reduce propfan noise in the cabin. To develop the baseline analysis, an acoustic cavity model of the aircraft interior and a structural dynamics model of the aircraft fuselage were created. The acoustic model was an indirect boundary element method representation using SYSNOISE, while the structural model was a finite-element method normal modes representation in NASTRAN and subsequently imported to SYSNOISE. In the acoustic model, the fan excitation sources were represented employing the Ffowcs Williams-Hawkings equation. The acoustic and the structural models were fully coupled in SYSNOISE and solved to yield the baseline response of acoustic pressure in the aircraft interior and vibration on the aircraft structure due to fan noise. Various vibration absorbers, tuned to fundamental blade passage tone (100 Hz) and its first harmonic (200 Hz), were applied to the structural model to study their effect on cabin noise reduction. Parametric studies were performed to optimize the number and location of these passive devices. Effects of synchrophasing and absorptive noise treatments applied to the aircraft interior were also investigated for noise reduction.
Microphone calibration and measurement uncertainties
Authors: Wong George S. K. , Wu Lixue
Published: October 2013

In acoustical measurement, the uncertainty of the front end components such as the microphone has to be taken into account together with the instrument measuring chain that follows. In this presentation, examples of uncertainties of microphone calibration are present with some discussions given on the tolerance limits provided by national and international standards for sound level meters. It is not surprising that one may find the uncertainty in a sound level measurement may be much higher than one expected.
Uncertainty in outdoor noise measurement and prediction
Authors: Wilson D. Keith
Published: October 2013

Standards for outdoor noise are intended to ensure that (1) measurements are representative of actual exposure and (2) noise prediction procedures are consistent and scientifically defensible. Attainment of these worthwhile goals is hindered by the many complexities of sound interaction with the local atmosphere and terrain. The paradigm predominant in current standards might be described as measuring/predicting ‘‘somewhat worse than average’’ conditions. Measurements/predictions are made for moderate downward refraction conditions, since that is when noise annoyance is most often expected to occur. This paradigm is reasonable and practical, although one might argue that current standards could implement it better. A different, potentially more rigorous, paradigm is to explicitly treat the statistical nature of noise imissions as produced by variability in the atmospheric environment and by uncertainties in its characterization. For example, measurements and prediction techniques could focus on exceedance levels. For this to take place, a better conceptual framework must be developed for predictions that are averaged over environmental states, frequency bands, and various time intervals. Another increasingly important issue is the role of computer models. As these models continue to grow in fidelity and capability, there will be increasing pressure to abandon standard calculations in many applications.