bluuebunny/crossref_metadata_2025 huggingface dataset:
A new scattering method that combines roughness and diffraction effects
Authors: Christensen Claus Lynge
Published: October 2013

Most of today’s room acoustics programs make use of scattering coefficients which are used in order to describe surface scattering (roughness of material) and scattering of reflected sound caused by limited surface size (diffraction). A method which combines scattering caused by diffraction due to typical surface dimension, angle of incidence, and incident path length with surface scattering is presented. Each of the two scattering effects is modeled as frequency dependent functions. The benefits are two-fold: (a) Separating the user specified surface scattering coefficient from the room geometry, makes it easier for the user to make good guesstimates of the coefficients which will be in better agreement with the ones which can be measured. In many cases a scattering coefficient of say 1% for all surfaces may be sufficient. (b) Scattering due to diffraction is distance and angle dependent and as such it is not known before the actual raytracing or image source detection takes place. An example of this is that a desktop will provide a strong specular component to its user whereas it will provide scattered sound at far distances.
The mechanical index and cavitation in tissue
Authors: Church Charles C. , Yang Xinmai
Published: October 2013

The mechanical index (MI) quantifies the likelihood that exposure to diagnostic ultrasound will produce an adverse biological effect by a nonthermal mechanism. The current formulation of the MI is based on inertial cavitation thresholds in two liquids, water and blood, as calculated by Apfel and Holland [Ultrasound Med. Biol. 17, 179–185 (1991)]. Although tissue contains a high proportion of water, it is not a liquid but a viscoelastic solid. The importance of this difference was studied by deriving a Keller-Miksis-like equation assuming a gas bubble in a linear Voigt solid and performing numerical computations similar to the analytical work underlying the MI. Thresholds for inertial cavitation were determined for pulse lengths of 1–14 acoustic periods, equilibrium bubble radii (Ro) of 0.1–10.0 mm, a frequency range of 0.5–15.0 MHz, 2 threshold (Pt) criteria: Rmax=2Ro, and Tmax=5000 K, and tissue elasticities and viscosities of G=0, 0.5, 1.0 or 1.5 MPa and μ=0.005 or 0.015 Pa⋅s; which span the range of values for soft tissue. It is found that thresholds in tissue are up to 10 times those in liquid, and that Pt increases nearly linearly with frequency. The relevance of these results to ultrasound safety will be discussed.
Specific acoustic impedance measurements of a thermoacoustic stack
Authors: Roh Heui-Seol , Raspet Richard , Bass Henry E.
Published: October 2013

Simmons [Ph.D. dissertation, University of Mississippi, 2003] attempted to use a two-microphone specific acoustic impedance (SAI) measurement of a thermoacoustic stack to determine the thermoviscous functions and the coefficient of the thermal gradient in the acoustic pressure differential equation for arbitrary geometry stacks. The proposed method was tested in part by comparing the measured and predicted SAI of a well-characterized parallel pore stack. Significant disagreement between theory and measurement occurred. In this paper the results of an improved four microphone SAI measurement on the well-characterized stack are reported. This measurement will reduce uncertainties in the transfer matrix method used by Simmons and determine if the discrepancies in Simmons work were experimental or if the thermoacoustic theory is incomplete.
The temporal effect for signal frequencies around a notched cochlear hearing loss
Authors: Strickland Elizabeth , Krishnan Lata
Published: October 2013

The temporal effect (or overshoot) refers to the change in signal-to-masker ratio at threshold for a short-duration tone as it is delayed from the onset of a longer-duration masker. This study is one in a continuing series of studies on the relationship between the temporal effect and the cochlear active process. In a previous study, the temporal effect was measured as a function of signal level in a broadband masker, for listeners with cochlear hearing loss. Results showed that the pattern of the temporal effect with level depended not only on the degree of hearing loss at the signal frequency, but also on the degree of hearing loss above the signal frequency. In the present study, this was examined further by measuring the temporal effect as a function of signal level in listeners with notched cochlear hearing loss, when the signal frequency was below, at or above the frequency of the greatest hearing loss (the notch). Results will be analyzed in terms of changes in the amplification due to the cochlear active process at and above the signal frequency. [Work supported by the Kinley Trust.]
Effect of signal frequency uncertainty for random multi-burst maskers
Authors: Huang Rong , Richards Virgina M.
Published: October 2013

The detectability of a sequence of equal-frequency tone pips masked by random multi-burst complexes may depend on the perceptual segregation of the signal stream from the random masker. If so, detection thresholds may be independent of whether the signal frequency is known versus uncertain. In this experiment observers detected a signal stream of 8 sequential equal-frequency 30 ms tone pips embedded in a random masker composed of 8 sequential bursts. A yes/no procedure was used, and the independent variable p (probability a tone was played at a particular time-by-frequency location) governed the number of masker tones in each burst. The dependent variable was d. Threshold values of p were obtained for signal streams at 5 different frequencies. Sensitivity was superior for the mid-frequency signal, and decreased as the signal frequencies approached the edge of the frequencies the masker tones occupied (200–5000 Hz). When the frequency of the signal stream was randomly varied from trial to trial, sensitivity was poorer than for any of the fixed-frequency signals. Thus, the detectability of a sequence of tone pips is reduced when the signal frequency is uncertain compared to certain. Additionally, sensitivity increased when the signal stream was delayed relative to the masker bursts.
Training listeners or preserving phase information improves the effect of perceived spatial separation on releasing spectrally degraded Chinese speech from information masking
Authors: Chen Jing , Ma Chenfei , Wang Chun , Qu Hongwei , Wu Xihong , Li Liang , Schneider Bruce
Published: October 2013

Physical or perceived spatial signal/masker separation unmasks speech more when maskers are informational than when energetic. However, it is unclear how beneficial the separations are to cochlear-implant listeners, because signal transductions applied in cochlear implant degrade signals spectrally, and spectrally degraded speech is more vulnerable to maskers. Here, spectrums of both target speech (nonsense sentence) and masker (steady speech-spectrum noise, speech modulated speech C-spectrum noise, or speech) were filtered into 15 frequency bands. For both target and masking speech, the center-frequency pure tone of each band was modulated by the extracted envelope from the band. The target speech was composed by the sum of the 8 odd-band tones, and the masker was either same-band (with the 8 odd-band tones) or different-band (with the 7 even-band tones). The results show that physical but not perceived spatial separation unmasked target speech in naive normal-hearing listeners. However, following pre-presentations of both degraded and normal correspondent speech to listeners for a period of time or the introduction of phase information into modulated tones, perceived spatial separation reduced the influence of different-band speech masking but not that of same-band speech masking. These results are useful for improving cochlear-implant programs at both behavioral and technical levels.
Design of a 6 degree of freedom anthropomorphic robotic jaw
Authors: Flores Edgar , Fels Sidney
Published: October 2013

We have created a 6 DOF robotic jaw capable of producing, in real-time, the complex set of motions described by the human jaw during speech or mastication. The jaw is designed to fit within a larger robotic human figure such as the head, neck and torso of the 25 DOF Infanoid. [Kozima, Hideki: Infanoid: A Babybot that Explores the Social Environment, K. Dautenhahn et al. (eds.), Socially Intelligent Agents: Creating Relationships with Computers and Robots, Kluwer Academic Publishers, pp. 157–164, 2002]. The produced mechanical prototype has been designed to accommodate a prosthesis mandible with dentures. The mechanism could fit within the skull of the average man; where it would occupy less than 1/3 of the skull cavity. Two TMJs (temporomandibular joints) support the prosthesis, where each is driven by a 3 DOF parallel manipulator. In order to combine the motion of both manipulators each TMJ is capable of 3 DOF. The system is controlled via a USB port using software that models the human skull including collision detection mechanisms. The jaw allows for linear control, zero-backlash, and up to three times exaggerated mobility ranges making it also suitable for speech research, facial gesture affect research and dentistry applications.
Classification of initial segments of sounds using onset data structures
Authors: Fraser Dagmar S. , Smith Leslie S.
Published: October 2013

Biologically motivated techniques are used to record onset data structures [L. S. Smith and D. S. Fraser, IEEE TNNS 15, 1125–1134 (2004)]. These structures record sets of events detailing both the spectral and intensity structure of sound onsets. They are inspired by the output spikes from onset cells in the cochlear nucleus. We suggest that the spectro-temporal characteristic of these structures provides useful information for classifying initial segments of sounds. The original onset data structure is of high dimensionality, and is difficult to interpret directly. A self-organizing feature map (SOFM or Kohonen network) is therefore used to provide a lower dimensional coding. The SOFM requires fixed-length data vectors, preferably not of too high a dimensionality. A number of different reformatting techniques are used to provide this. For the SOFM, identified activated map areas are associated with particular sounds. Using the TIMIT database these areas can be labelled, providing a testable classification scheme. This is compared with other work classsifying TIMIT phonemes. We believe that the SOFM can be extended to classify the onsets of other (non-speech) sounds. [Work supported by UK EPSRC.]
Deriving speaking rate effects on tonal realization without varying the speech rate
Authors: Yu Alan C. L.
Published: October 2013

Previous research investigates the effect of durational variation on tonal realization by artificially inducing a change in speaking rate. Through an investigation of the f0 pattern of Cantonese mid-rising tone, this paper introduces a novel, indirect, method of investigating durational effect on tonal realization by looking at the variation in tonal realization in different syllable types. Cantonese has three syllable types: CV, CV(V)O, CV(V)N. CV(V)N syllables are found to be significantly longer than CV syllables, which in turn are significantly longer than CV(V)O syllables. In this study, five native Cantonese speakers were asked to recite a list of Cantonese words with a mid-rising tone in a carrier phrase. The f0 of the Turning Point (the lowest point of a rise), the f0 peak of the rise, the durations of the Turning Point and the f0 peak relative to the onset of voicing, and the duration of the syllable rime were measured. The results show that the f0 peak frequency remains constant regardless of the duration of the syllable. The f0 of the Turning Point gets higher when the duration of the syllable becomes shorter. Finally, the slope of the f0 rise remains constant regardless of the duration of the syllable.
Automatic detection of microchiroptera echolocation calls from field recordings using machine learning algorithms
Authors: Skowronski Mark D. , Harris John G.
Published: October 2013

The authors have recently presented experimental results of applying machine learning algorithms, used extensively in human automatic speech recognition research (ASR), to automatic species identification of echolocating bats [Skowronski and Harris, J. Acoust. Soc. Am. 116, 2639 (2004)]. The results of those experiments demonstrated that frame-based classification, preferred in ASR, out-performs holistic classification typically employed in automatic echolocating species identification. The authors have extended the paradigm of machine learning algorithms to the related problem of bat call detection. A robust automatic bat call detection algorithm, to replace hand labeling, is required for two reasons: (1) for real-time species identification in the field, and (2) because hand labeling is subjective, tedious, slow, and error-prone. The current experiments compare various frame-based features (log energy, pitch estimates, pitch slopes) with several models of detection (matched filters, Gaussian mixtures, decision trees). Detector sensitivity and specificity are quantified for comparison using hand-labeled calls, with considerations of classification requirements for detected calls. That is, a detector is not penalized for including a short segment of background signal before and after a hand-labeled call. The results demonstrate the superior performance of the frame-based features and machine learning detection algorithms compared to conventional features and detection algorithms.
Sound absorbers with micro-perforated stretched foils and porous materials
Authors: Nocke Christian , Hilge Catja , Scherrer Jean-Marc
Published: October 2013

At the spring meeting 2004 in New York first results for the sound absorption of micro-perforated stretched foils have been presented. The classical set-up of a micro-perforated sound absorber consists of a micro-perforated panel in front of an air cavity. The sound absorption coefficient of these set-ups can easily calculated with a high accuracy according to the well-known approximation of D.-Y. Maa if all defining geometrical parameters (diameter of microperforation, distance between orifices, panel thickness and air cavity depth) are known. In this contribution measured sound absorption coefficients of other set-ups with micro-perforated foils as well as combinations with different porous materials will be presented. For these assemblies no closed calculation model exists so far. Comparisons between computer-based calculations of layered absorber set-ups show promising results for some assemblies. Finally different applications in various rooms will be presented. As expected the comparison between theoretical design and the final result show a very high degree of agreement.
The impact of helmet design on sound detection and localization
Authors: Scharine Angelique
Published: October 2013

The shape and absorptiveness of a ballistic helmet changes the sound signal reaching the soldier’s ear. Although the attenuation of current helmets is minimal, soldiers have reported removing their Personnel Armor System for Ground Troops (PASGT) helmet when it was necessary to determine sound source direction. The Advanced Combat Helmet (ACH) has reduced ear coverage and absorptive internal padding that decreases localization errors. In an effort to provide more integrated headgear, the U.S. Army is testing a new, Scorpion (R4) helmet that has rings that allow the insertion of earmuffs and a modified version without the rings (R4-R). Two studies were conducted to measure the effect of these four designs on sound detection and localization. None of the helmets differed significantly in the degree of attenuation nor did attenuation correlate with localization. However, localization performance varied greatly. The current ACH and the R4-R had the least impact on localization. The older, unpadded PASGT, caused high error rates despite having the lowest attenuation. Despite being otherwise similar to the R4-R, the R4 impaired localization just as much as the PASGT and its rings increased the attenuation by more than a decibel.
Principal components analysis interpolation of head related transfer functions using locally-chosen basis functions
Authors: Scarpaci Jacob W. , Colburn H. Steven
Published: October 2013

Spatial interpolation between measured head related transfer functions (HRTFs) may be accomplished by using principal components analysis (Kistler and Wightman, 1992). The data set can be reduced by using only the most important basis functions (BFs) when reconstructing the magnitude spectrum of the HRTFs. Relatively good performance can be achieved by using a small fraction of the BFs required for an error free representation. In this study a comparison is made between two methods for choosing which basis functions are included in the HRTF reconstruction for a given position. The usual approach is to choose the subset of BFs which have the largest impact (common variance) on the global set of measured HRTFs. This will be compared to a method in which the subset of BFs are chosen to have the largest impact on the measured HRTFs in the area local to the position being reconstructed. Advantages and disadvantages to the two methods are discussed. [Work supported by NIH DC00100.]
Perception of ‘‘asymmetrical’’ German vowels by humans, monkeys and gerbils
Authors: Sinnott Joan M. , Long Leigh Ann , Ernst Allen C.
Published: October 2013

Polka and Bohn [J. Acoust. Soc. Am. 100, 557–592 (1996)] report that human infants perceive certain vowels asymmetrically when tested with a repeating-background category-change operant headturn procedure. Specifically, discrimination is easier when the background is a more central vowel (e.g. /y/) and the target is a more peripheral vowel (e.g. /u/), compared to the opposite condition. We are testing human (adult native English listeners) and monkey discrimination of the German vowel pair /dut-dyt/, using both synthetic and natural stimuli (obtained from Polka and Bohn), and a within-subject design. So far, no significant asymmetries have emerged in the data using a percent correct measure. We will also report preliminary data from gerbils being trained in a between-subject design more comparable to that used with human infants. Plans are to continue testing all species until they reach asymptotic performance levels in order to determine if an RT measure will indicate vowel asymmetries. A video will be shown of humans, monkeys and gerbils working on the experiments.
Effects of simultaneously presented pitch- and loudness-shifted voice auditory feedback on voice fundamental frequency
Authors: Larson Charles R. , Sun Jean , Takaso Hideki
Published: October 2013

Recent studies have demonstrated that subjects respond to pitch- or loudness-shifted voice feedback with compensatory changes in voice fundamental frequency (F0) or intensity. In the present study, subjects sustaining /u/ vowel sounds were presented with either pitch-shifted auditory feedback (50 or 100 cents) or simultaneous pitch-shifted and loudness-shifted voice feedback (3 or 6 dB SPL) of 200 ms duration. During simultaneous stimulus presentations, the stimulus directions were opposite in direction (e.g., increasing pitch and decreasing loudness feedback). Subjects (N=24, normal, age 18–24) responded to pitch-shifted feedback with compensatory adjustments in F0. Subjects responded to simultaneous stimuli with independent compensatory adjustments in voice F0 and intensity. Latencies of F0 responses to simultaneous stimuli (m=211 ms) were longer than to pitch-shifted stimuli alone (m=145 ms, F=26, df 2306; p<.0001). Results suggest auditory feedback mechanisms for stabilizing the direction of voice F0 against perturbed pitch feedback are independent of mechanisms for stabilizing loudness feedback, but the simultaneous presence of pitch and loudness perturbations slows down the corrective mechanism for pitch-shifted feedback.
The effects of signal-to-noise ratio on auditory-visual integration: Integration and encoding are not independent
Authors: Sommers Mitchell S. , Spehar Brent , Tye-Murray Nancy
Published: October 2013

Most current models of auditory-visual speech perception propose a two-stage process in which unimodal information is extracted independently from each sensory modality and is then combined in a separate integration stage. A central assumption of these models is that integration is a distinct perceptual ability that is separate from the ability to encode unimodal speech information. The purpose of the present study was to evaluate this assumption by measuring integration of the same speech materials across three different signal-to-noise ratios. Twelve participants were presented with 42 repetitions of 13 consonants presented in an /iCi/ environment at 3 different signal-to-noise ratios. Integration was assessed using an optimum processor model [L. Braida, Q. J. Exp. Psych. 43A, 647–677 (1991)] and a new measure termed integration efficiency that is based on a simple probability metric. In contrast to predictions made by current models of auditory-visual speech perception, significant differences were observed for both measures of integration as a function of signal-to-noise ratios. These findings argue against strictly serial models of auditory-visual speech perception and instead support a more interactive architecture in which unimodal encoding interacts with integration abilities to determine overall benefits for bimodal speech perception. [Work supported by NIA.]
A simplified method to estimate the free path length variance
Authors: Zhang Yan , Augenbroe Godfried , Choudhary Ruchi , Vidakovic Brani
Published: October 2013

Kutruff derived an analytical solution for the prediction of reverberation time in spaces with arbitrary shape. It is the most popular analytical equation that contains shape factors. However, in this equation the free path length variance remains as unknown parameter. Kutruff suggested the implementation of Monte-Carlo simulation to determine this value for each unique shape. In practice this method is not significantly simpler than a full ray tracing simulation. Fortunately, using methods from the probability field, the free path length variance does have an analytical solution, but this takes such a complicated form that it is not convenient to use. This article treats the development of a simplified method to estimate the free path length variance without losing accuracy when applied to concert halls. A simplified regression model is developed for rectangular shapes based on the analytical solution. This simple model explains 99.8% variance for any rectangular shape up to 1:10:10. Secondly, for arbitrary shapes, a simplified model is proposed by including several additional simple variables. This model is validated against simulation results. It will be shown that this simplified method not only can be used in Kutruff’s equation, but also reveals the significant shape-related parameters that influence the reverberation time.
Sound field simulation and acoustic animation in urban squares
Authors: Kang Jian , Meng Yan
Published: October 2013

Urban squares are important components of cities, and the acoustic environment is important for their usability. While models and formulae for predicting the sound field in urban squares are important for their soundscape design and improvement, acoustic animation tools would be of great importance for designers as well as for public participation process, given that below a certain sound level, the soundscape evaluation depends mainly on the type of sounds rather than the loudness. This paper first briefly introduces acoustic simulation models developed for urban squares, as well as empirical formulae derived from a series of simulation. It then presents an acoustic animation tool currently being developed. In urban squares there are multiple dynamic sound sources, so that the computation time becomes a main concern. Nevertheless, the requirements for acoustic animation in urban squares are relatively low compared to auditoria. As a result, it is important to simplify the simulation process and algorithms. Based on a series of subjective tests in a virtual reality environment with various simulation parameters, a fast simulation method with acceptable accuracy has been explored. [Work supported by the European Commission.]
The effects of tongue shape categories on tongue segmentation in English
Authors: Epstein Melissa A. , Stone Maureen
Published: October 2013

In our recent work, we have proposed that the tongue moves by compressing and expanding local functional segments. For any single gesture, functional segments may move in similar or opposite directions to compress and expand the tongue locally. High correlations between segments suggest biomechanical constraints. Low correlations suggest independent control of these segments. Our previous studies on English have shown a front-back division of the tongue, where adjacent segments correlate positively with each other (moving in the same direction) and distal segments correlate negatively with each other (moving in opposite directions). Individual segments aggregate with adjacent or distal segments. Furthermore, the phonemic content of the dataset influences these aggregations and the location of the front-back division of the tongue. This study will more deeply explore these phonemic effects. In particular, we will examine the effects of the transitions between consonants and vowels of the four basic tongue shape categories of English [front raising (e.g., /n,i/), back raising (e.g., /ng,o/), complete channel (e.g., /s,ae/) and two point displacement (e.g., /l/)] on tongue segmentation and the location of the pivot point for the front-back division. [Work supported in part by NIDCD/NIH Grant RO1-DC01758 and by NIH Grant T32-DE07309.]
Acoustic self-localization of a wireless sensor network
Authors: Schmidt Peter L. , Williams Stephen M. , Frampton Kenneth D.
Published: October 2013

One of the biggest challenges to the field of wireless sensor networks is self-localization: that is the determination of the relative and absolute coordinates of each sensor node in the network. Previous work has been done to locate hydrophone arrays. However sensor networks have some unique constraints that make this more challenging. A typical application would involve the distribution of hundreds or thousands of sensor nodes over an area either by hand, airdrop or other means. One of the primary constraints on such a system is that centralized processing of self-localization data may be prohibitively complex. Furthermore, the data may be incomplete, contain reflected path events, and may be subject to other mission specific constraints. Therefore, a distributed computational scheme has been developed to solve acoustic time-of-arrival equations. A priori information about some sensor locations and user triggered source localization events are used along with a regularized inversion solution. Results of this will be presented based on both small scale experiments and larger systems simulations. Limits of the types of a priori information required for accurate results are detailed, along with studies of the accuracies obtained using various distributed calculations parameters.
Interacting bubble dynamics in Hamiltonian mechanics
Authors: Ilinskii Yurii A. , Hamilton Mark F. , Zabolotskaya Evgenia A.
Published: October 2013

A Hamiltonian formulation of the equations of motion is presented for the oscillation and 3D translation of N interacting spherical bubbles. Existing alternative formulations contain second derivatives of both the bubble radius and the three coordinates of the position vector. For two or three bubbles the systems may be reduced analytically to explicit first-order equations that can be solved with standard numerical algorithms. For large N, the equations cannot realistically be recast in explicit first-order form, and the leading derivatives must be evaluated by matrix inversion at each time step. The inversions introduce substantial errors for large N. We avoid the inversions by using Hamiltonian mechanics to derive a system of explicit first-order equations for all N, and which includes the influence of an applied sound field. For large N, the approach based on Hamiltonian mechanics results in both increased numerical accuracy and reduced computation time. The Hamiltonian system is validated by comparison with solutions obtained by alternate means. Examples are presented demonstrating various effects of bubble interaction. Although developed for modeling cavitation in shock-wave lithotripsy, the model is also applicable to bubble clouds in the ocean. [Work supported by NIH Grant EB004047 and ARL IR&D funds.]
Convergence rates for diffuse field-field correlations
Authors: Weaver Richard
Published: October 2013

A model of diffuse fields in open structures is taken to be that resulting from a Gaussian random distribution of sources spread over all space. It is shown, consistent with recent literature, that this ensemble of fields gives rise to a field-field correlation function R between two points that has expectation 〈R〉 equal to the Green’s function between those points. It is furthermore found that this model lends itself to calculations of the variance of R, and thus to estimates of the degree to which an R calculated using finite amounts of data will conform to the Green’s function. The model indicates, in accord with observations, that such conformation is strongest at low frequencies. Ray arrivals are detectable only if sufficient data has been collected; the amount of data needed scales with the square of the source-receiver separation, and the square of the frequency. Applications to seismology are discussed.
Cues used for distinguishing African American and European American voices
Authors: Thomas Erik R. , Lass Norman J.
Published: October 2013

Past studies have shown that listeners can distinguish most African American and European American voices, but how they do so is poorly understood. Three experiments were designed to investigate this problem. Recordings of African American and European American college students performing various reading tasks were used as the basis for stimuli in all three. In the first experiment, stimuli were subjected to monotonization, lowpass filtering at 660 Hz, and no modification. In the second, stimuli featuring certain ethnically diagnostic vowels and control stimuli were subjected to monotonization, conversion of vowels to schwa, or no modification. In the third, stimuli featuring diagnostic vowels and control stimuli were modified so that the intonation of paired African American and European American speakers was swapped. In all three experiments, African American and European American listeners in North Carolina and European American listeners in West Virginia identified the ethnicity of the speaker of each stimulus. Vowel quality emerged as the most consistent cue for identifications. However, listeners accessed other cues differently for male and female speakers. Breathiness was correlated with identifications of male speakers but not of female speakers. F0-related factors proved more important for female speakers than for male speakers. [Work supported by NSF.]
Initial investigations into thermoacoustic coal agglomerators
Authors: Smith Gordon
Published: October 2013

Each year, Kentucky coalmines produce about 160 million tons of coal, mainly used to generate electricity at power plants in Kentucky and throughout the midwestern and southeastern United States. Coal processing generates an excessive amount of pollution in the form of heavy exhaust, which creates an environmental concern. In response to this growing concern for a balance between environmental impact and energy production, many processing plants utilize electrostatic precipitation (ESP) systems to agglomerate and filter out particulate matter (PM) from exhaust streams before they enter the general environment. However, ESP efficiency is limited by the size of the particulate exhaust. Particle agglomeration also results via time-averaged forces inherent in an acoustic standing wave. Thermoacoustic technology, which utilizes waste heat sources for operation, embodies an ideal source for providing the requisite acoustic conditions. This technology could also be installed to supplement existing technology as a preconditioner (increasing the particle size to one more suitable for current ESP systems), and increase the overall PM removal efficiency. This talk will present initial investigations into applying thermoacoustic technology to this problem.
Augmented and selective delivery of liquid perfluorocarbon nanoparticles to melanoma cells with ultrasound
Authors: Hughes Michael S. , Crowder Kathryn C. , Lanza Gregory M. , Wickline Samuel A.
Published: October 2013

Previous work has demonstrated the ability of liquid perfluorocarbon (PFC) nanoparticles to deliver therapeutic agents to cells selectively by binding to specific cellular epitopes, and confirmed the ability to simultaneously image these targeted nanoparticles with ultrasound. In this study, enhanced delivery of targeted PFC nanoparticles to cells expressing the integrin avb3 using clinical levels of ultrasound energy were studied. Nanoparticles complexed with ligands targeted to avb3 were incubated with cells (C32 melanoma) that expressed avb3 in culture. Control nanoparticles were produced that carried no ligand targeted to avb3. A custom specimen holder permitted simultaneous microscopic visualization of cell interactions during exposure to calibrated levels of ultrasound energy. After nanoparticle binding to cells and application of ultrasound, a roughly 2-fold increase in PFC content of the cells was observed. For control (nonbinding) nanoparticles, ultrasound exposure also increased PFC deposition, but the overall level was substantially less. Videodensitometric data show that nanoparticles were not destroyed by ultrasound exposure. Moreover, the alignment of nanoparticles relative to incident acoustic field demonstrate conclusively that acoustic radiation forces influence the nanoparticles and implicate these forces as participates in the enhanced delivery.
Vibro-acoustic response of convected fluid loaded plates
Authors: Frampton Kenneth
Published: October 2013

This work demonstrates the effects that fluid convection has on the vibro-acoustic response of rectangular plates. The effects of fluid flow on the vibration and stability of plates is reasonably well understood. These effects include dramatic structural modal coupling along with static and dynamic instabilities. However, the resulting effect on sound radiation is not so well understood. The presentation will include a description of the fundamental physics associated with a simply supported, vibrating, rectangular plate in an infinite baffle and radiating into a semi-infinite, convected fluid. Then, simulation results will demonstrate the effects of flow-induced modal coupling and acoustic radiation. It will be demonstrated that convection can significantly increase the radiated sound power and dramatically affect the vibro-acoustic response.
Perception of steady-state vowels and vowelless syllables by adults and children
Authors: Nittrouer Susan
Published: October 2013

Vowels can be produced as long, isolated, and steady-state, but that is not how they are found in natural speech. Instead natural speech consists of almost continuously changing (i.e., dynamic) acoustic forms from which mature listeners recover underlying phonetic form. Some theories suggest that children need steady-state information to recognize vowels (and so learn vowel systems), even though that information is sparse in natural speech. The current study examined whether young children can recover vowel targets from dynamic forms, or whether they need steady-state information. Vowel recognition was measured for adults and children (3, 5, and 7 years) for natural productions of /dæd/, /dUd/ /æ/, /U/ edited to make six stimulus sets: three dynamic (whole syllables; syllables with middle 50-percent replaced by cough; syllables with all but the first and last three pitch periods replaced by cough), and three steady-state (natural, isolated vowels; reiterated pitch periods from those vowels; reiterated pitch periods from the syllables). Adults scored nearly perfectly on all but first/last three pitch period stimuli. Children performed nearly perfectly only when the entire syllable was heard, and performed similarly (near 80%) for all other stimuli. Consequently, children need dynamic forms to perceive vowels; steady-state forms are not preferred.
Acoustic scattering from an obstacle in a homogeneous non-uniform moving medium via the ray method
Authors: Semenova Tatiana
Published: October 2013

For an accurate noise prediction for aircraft in forward flight, scattering of engine noise from airframe must be included into the description of the sound field. A realistic model of acoustic scattering by airframe in flight must account for the effects of the background flow. We consider acoustic scattering from an obstacle in the presence of a time-independent background flow at low Mach number and we neglect all other effects of the variation of the medium on sound propagation. The model is based on a convected Helmholtz equation with coefficients dependent on the background flow, which can be given either analytically or by CFD. A high-frequency solution is sought by the ray acoustics with a simple method based on the Fresnel volumes of the rays employed to determine the caustic zones and the field on the caustics. The weaker effects of a tip or smooth-body diffraction are neglected and only the reflection and edge diffraction are taken into account. The source of noise is modeled as a point source. The upstream shielding effect of a boundary layer is investigated as an example and uniform versus non-uniform flow effects are illustrated. Other numerical examples will be considered. [Work supported by NRC.]
A high frequency time reversal array deployment in a very shallow water environment
Authors: Folegot Thomas , Clorennec Dominique , Minonzio Jean-Gabriel , de Rosny Julien , Prada Claire , Fink Mathias , Hibral Sidonie , Berniere Lothar
Published: October 2013

A new rigid 24-element acoustic source receiver array in the 10 to 15 kHz frequency band has recently been developed [Folegot et al., submitted to OCEANS2005-Europe]. Despite of a height of 10 m, it has been specified to be easily deployed from a pier and to allow low cost at-sea experiments with water depth up to 12 m. The array has been deployed in a pool of 50 m length and 10 m depth, where calibrated surface plane waves have been generated. The objective of the trial was to undertake a first deployment of the system, to calibrate the instrument and provide some scientific results based on time reversal in a very controlled experimental setup. The Time Reversal Operator has been measured in several configurations. Subsequently, its eigenvectors associated with target reflections have been emitted by the mirror in order to focus separately on each target. The sensitivity of the method against target depth, target type, emission basis, and surface roughness has been investigated. The collected data will help to improve the understanding of environmental factors affecting acoustic propagation in the 10–15 kHz range and will make an important contribution to the development of advanced acoustic communications methods and tomographic capabilities.
Well- and ill-considered numerical solution constructions
Authors: McCoy John J.
Published: October 2013

One requirement for a prediction problem to be well posed is that its solution must not be unduly sensitive to small changes in the problem specification. A similar requirement can be demanded for the numerical construction of the solution of a well-posed problem to be well considered; the achieved solution must not be unduly sensitive to small numerical errors that are unavoidable in the construction’s implementation. Ill-considered constructions typically result on reformulating a well-posed problem, now as a series of sub problems, one of which is ill posed. Three classes of potentially ill-considered constructions of the steady state vibration field in a bounded continuous structure and of the narrow band acoustic field in an extended propagation environment appear prominently in the literature. One class is solution constructions based on ‘‘marching.’’ A second class is solution constructions based on ‘‘substructuring’’ the computational domain. A third class is solution constructions that are based on a Born-series representation. Examples of well- and ill-constructions for each of the classes are briefly described, with well- and ill-considered marching solutions discussed in some detail.
Deep Brain Stimulation of the Midbrain Locomotor Region Improves Paretic Hindlimb Function After Spinal Cord Injury in Rats
Authors: Bachmann Lukas C. , Matis Alina , Lindau Nicolas T. , Felder Petra , Gullo Miriam , Schwab Martin E.
Published: October 2013

Stimulating the midbrain improves gait and locomotion in rats with chronic spinal cord injury.
A New Hope for Precision Medicine
Authors: Salgia Ravi , Sattler Martin
Published: October 2013

The SS1P immunotoxin is combined with immunomodulatory therapy in order to improve its efficacy in human mesothelioma (Hassan
et al
., this issue).
Refractory postsurgical pyoderma gangrenosum in a patient with Beckwith Wiedemann syndrome: response to multimodal therapy
Authors: Fakhar Faiza , Memon Sehrish , Deitz Diane , Abramowitz Richard , Alpert Deborah R
Published: October 2013

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that may be difficult to diagnose and treat. We presented a 41-year-old woman who required skin grafting following third-degree burns to her left breast. She suffered recurrent graft dehiscence and infections over many years, prompting elective bilateral reduction mammoplasty. She subsequently developed suture margin ulcerations unresponsive to topical therapies and antibiotics. Skin biopsies were non-specific, and a clinical diagnosis of PG was established. Although initially responsive to corticosteroids, wounds promptly recurred following steroid taper. She was treated unsuccessfully with various immunomodulatory agents and underwent elective bilateral mastectomy. Following a mastectomy, she developed progressive deep chest wall ulcerations. She failed numerous immunomodulatory treatments, surgical wound closure and negative pressure wound therapy. Ultimately, treatment with adalimumab, mycophenolate mofetil and prednisone, in addition to hyperbaric oxygen therapy facilitated progressive healing. Our case highlights the role of collaborative multimodal therapy for the treatment of refractory PG.
The CARE guidelines: consensus-based clinical case reporting guideline development
Authors: Gagnier Joel J , Kienle Gunver , Altman Douglas G , Moher David , Sox Harold , Riley David ,   the CARE Group
Published: October 2013

A case report is a narrative that describes, for medical, scientific or educational purposes, a medical problem experienced by one or more patients. Case reports written without guidance from reporting standards are insufficiently rigorous to guide clinical practice or to inform clinical study design. Develop, disseminate and implement systematic reporting guidelines for case reports. We used a three-phase consensus process consisting of (1) premeeting literature review and interviews to generate items for the reporting guidelines, (2) a face-to-face consensus meeting to draft the reporting guidelines and (3) postmeeting feedback, review and pilot testing, followed by finalisation of the case report guidelines. This consensus process involved 27 participants and resulted in a 13-item checklist—a reporting guideline for case reports. The primary items of the checklist are title, key words, abstract, introduction, patient information, clinical findings, timeline, diagnostic assessment, therapeutic interventions, follow-up and outcomes, discussion, patient perspective and informed consent. We believe the implementation of the CARE (CAse REport) guidelines by medical journals will improve the completeness and transparency of published case reports and that the systematic aggregation of information from case reports will inform clinical study design, provide early signals of effectiveness and harms, and improve healthcare delivery.
Associations between objectively measured physical activity and academic attainment in adolescents from a UK cohort
Authors: Booth J N , Leary S D , Joinson C , Ness A R , Tomporowski P D , Boyle J M , Reilly J J
Published: October 2013

Background

To test for cross-sectional (at age 11) and longitudinal associations between objectively measured free-living physical activity (PA) and academic attainment in adolescents.Method Data from 4755 participants (45% male) with valid measurement of PA (total volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (ALSPAC) was examined. Data linkage was performed with nationally administered school assessments in English, Maths and Science at ages 11, 13 and 16.

Results

In unadjusted models, total volume of PA predicted decreased academic attainment. After controlling for total volume of PA, percentage of time spent in moderate-vigorous intensity PA (MVPA) predicted increased performance in English assessments in both sexes, taking into account confounding variables. In Maths at 16 years, percentage of time in MVPA predicted increased performance for males (standardised β=0.11, 95% CI 0.00 to 0.22) and females (β=0.08, 95% CI 0.00 to 0.16). For females the percentage of time spent in MVPA at 11 years predicted increased Science scores at 11 and 16 years (β=0.14 (95% CI 0.03 to 0.25) and 0.14 (0.07 to 0.21), respectively). The correction for regression dilution approximately doubled the standardised β coefficients.

Conclusions

Findings suggest a long-term positive impact of MVPA on academic attainment in adolescence.
Recanalization of acute carotid stent occlusion using Penumbra 4Max aspiration catheter: technical report and review of rescue strategies for acute carotid stent occlusion
Authors: Munich Stephan , Moftakhar Roham , Lopes Demetrius
Published: October 2013

Carotid artery stenting (CAS) has become a widely used treatment for carotid artery stenosis, especially in high-risk patients. Acute in-stent and distal protection device occlusion are potentially catastrophic complications of this procedure. Previously described rescue strategies have included administration of antiplatelet agents (eg, abciximab) with/without thrombolytics and removal of the filter. Here we describe the successful resolution of in-stent occlusion by mechanical thrombolysis using the Penumbra 4Max aspiration catheter. Distal flow was subsequently restored with minimal residual stenosis. The patient did not suffer any consequent neurological deficits. The different strategies that could be used in this critical situation are reviewed.