bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic correlates of comorbid voice and resonance impairment in individuals with amyotrophic lateral sclerosis
Authors: Eshghi Marziye , Connaghan Kathryn , Gutz Sarah , Eshghi Mohammad , Berry James , Yunusova Yana , Green Jordan
Published: November 2019

Assessment of voice and resonance impairment in amyotrophic lateral sclerosis (ALS) may be challenging due to multi-speech subsystem involvement. Although several acoustic measures have been associated with isolated voice and resonance impairment, their efficacy in the presence of comorbid voice-resonance impairment is unclear. The goal of this work is to determine acoustic features that correlate with perceptual judgment of voice and resonance severity in patients with ALS, and identify measures capable of differentiating phonatory, resonance, and co-occurring impairments. Two listeners rated resonance and voice impairment severity of repetitions of “Buy Bobby a puppy” produced by 26 participants with ALS. Samples were stratified based on perceptual ratings: bulbar asymptomatic, predominantly phonatory involvement (i.e., abnormal voice), predominantly resonatory involvement (hypernasality), and mixed (phonatory and resonance involvement). Groups were compared using resonance (one-third octave analysis) and phonatory (cepstral/spectral) measures. The one-third octave analysis differentiated all groups (p < 0.05); the cepstral peak prominence differentiated all groups (p < 0.01) except asymptomatic versus mixed; and the low/high spectral ratio did not differ between groups. Findings illustrate the challenges of implementing targeted resonance and voice measures in the presence of multi-speech system involvement, though one-third octave analysis is a promising approach to quantifying voice and resonance impairment in ALS.
Pitch accent perception and autistic traits for non-native listeners
Authors: Kuo Grace
Published: November 2019

This study examines the role of the autistic traits in predicting the prosodic prominence for non-native listeners. The subjects completed the Autism Spectrum Quotient (AQ: Baron-Cohen et al., 2001) questionnaire and participated in the Rapid Prosody Transcription Task (Cole et al., 2010), where they marked the prominent words and prosodic boundaries of Barack Obama’s political speech recordings (475 s in total). The recordings were previously annotated by two trained phoneticians using the ToBI (Tones and Break Indices) conventions for Mainstream American English (Beckman, 1997). Previous studies have shown that native speakers and L2 learners use different acoustic measures as predictors of their perception of prosodic prominence (Pintér et al., 2014; You, 2012). Furthermore, Iao et al. (2017) found that individuals who were less sociable were less able to discriminate foreign lexical pitch difference. Therefore, this study takes intrinsic individual difference into account (assessed by AQ) to see its effect on the perception of pitch accents in English for non-native listeners. The overall results will also speak to issues regarding the development of prosody acquisition and the role of attention in prosodic processing.
Acoustical oceanography with a single hydrophone: Propagation, physics-based processing and applications
Authors: Bonnel Julien
Published: November 2019

Lobsters, whales and submarines have little in common. Except that they produce low-frequency sound, like many other marine occupants that use sound for communication, foraging, navigation and other purposes. However, unraveling and using the underwater cacophony is not at all simple. This is particularly true for low-frequency (f < 500 Hz) propagation in coastal water (water depth D < 200 m), because the environment acts as a dispersive waveguide: the acoustic field is described by a set of modes that propagate with frequency-dependent speeds. In this context, to extract relevant information from acoustic recording, one needs to understand the propagation and to use physics-based processing. In this tutorial-like presentation, we will show how to analyze low-frequency data recorded on a single hydrophone. We will notably review modal propagation and time-frequency analysis. We will then show how those can be combined into a non-linear signal processing method dedicated to extract modal information from single receiver, and how such information can be used to localize sound sources and/or characterize the oceanic environment. The whole method will be illustrated on several experimental examples, including geoacoustic inversion on the New England Mud Patch and baleen whale localization in the Arctic.
A method to virtually extend reverberation time of measured impulse responses without losing room coloration
Authors: LeBlanc Lévy , Gauthier Philippe-Aubert , Berry Alain
Published: November 2019

For various audio and acoustical applications, it is useful to modify the reverberation time of a measured room impulse response. For example, it can be interesting for creating various modified impulse responses for convolution reverbs in video games or sound designs. With this in mind, it is proposed to modify an impulse response reverberation time while keeping the other reverberation characteristics, such as the frequency response, unaffected. Knowing how a typical impulse response is related to the room characteristics, we propose a new method. First, the impulse response of a room is measured. Then, the reverberation time is evaluated. This reverberation time is next approximated by Sabine-Eyring equation, resulting in an absorption coefficient. A new absorption coefficient is then manually provided to reach a new target reverberation time. Finally, the late reverberation of the original impulse response is convolved with a gaussian white noise to the desired length and stitched with appropriate decaying envelopes to the end of the initially measured impulse response. This paper illustrates that the method works based on simulations and that the modified impulse response is realistic and can be related to the actual room.
Achieving consensus and convergence on a towed array passive acoustic monitoring standard for marine mammal monitoring
Authors: Thode Aaron , Guan Shane
Published: November 2019

Towed passive acoustic monitoring (PAM) arrays from surface vessels has become a mature technology for marine mammal monitoring during marine seismic surveys. Multiple U.S. federal agencies have expressed a desire for consistent standards when implementing towed PAM. Two workshops involving academics, commercial PAM operators, and regulators have led to a comprehensive outline for an ASA towed array draft standard that covers requirements for initial operation planning, hardware, real-time monitoring and data acquisition, localization procedures, and post-operation validation. It does not cover operational mitigation decision criteria (such as power-down and/or shutdown of seismic airgun arrays), sound source verification, or how to initially establish the required detection range of the system. The standard’s fundamental goal is to reduce situations where background noise levels (arising from a variety of mechanisms) prevent effective PAM, and the dominant strategy employed is to standardize how acoustic measurements are logged, reported, and evaluated. Standardized plots would permit a non-technical supervisor or regulator to easily determine whether the PAM operation was self-noise limited under multiple operational circumstances. The approach taken here can serve as a template for future PAM standards for other deployment platforms [Work sponsored by BSSE and ONR Living Marine Resources Program.]
Laboratory rats (Rattus norwegicus) detect the Fanssen effect
Authors: Collins Alayna L. , Hill Evan M.
Published: November 2019

The purpose of this study was to determine whether laboratory rats (Rattus norwegicus) were able to detect the Franssen Effect (FE). The FE is elicited by simultaneously presenting a spatially split signal to the left and right of the listener. One side presents a transient tone with rapid linear offset and the opposite presents a sustained tone with a ramped onset. The listener perceives a single, sustained tone localized on the side of the transient signal. Previous research demonstrated perception of the FE in three mammalian species by monitoring gaze-shift via the scleral search coil technique. However, this method requires placing contact lenses in each eye and restraining non-human subjects, making it suboptimal for use in many species. Alternatively, two species of bird were shown to detect the FE using an operant behavioral method. The current study used a similar two-choice procedure to determine detection of the FE in octave steps, ranging from 1–32 kHz. The results of this study found that laboratory rats also detect the FE. Human participants also demonstrated detection of the FE using this behavioral technique at rates comparable to the previous literature. Therefore, this behavioral methodology is a viable option for testing this auditory phenomenon.
Cylindrical ultrasound transducers for intravascular and endolumenal imaging applications
Authors: Herickhoff Carl , Telichko Arsenii , Dahl Jeremy J.
Published: November 2019

Conventional ultrasound imaging transducers are fabricated using planar geometries—of materials and in most subsequent processing (bonding, dicing, etc.); this can lead to complications in assembling catheter- or endoscope-based devices, and/or significant inherent limitations in their design and application. Miniature cylindrical transducer devices offer the potential for more straightforward design for 360-deg imaging applications, albeit with unique fabrication challenges. We have developed a novel technique for processing cylindrical ultrasound transducer geometries, and used it to fabricate prototype devices designed for intravascular and endolumenal applications. We created a custom dicing setup allowing a tube of radially poled piezoceramic (PZT-4) as small as 4.6 Fr (1.53 mm diameter) to be cut circumferentially, to a specified depth or completely through the wall of the tube, at precise axial locations. The resulting cylindrical transducer was connected to a function generator and power amplifier, and driven at 7.5 MHz to generate axisymmetric, radially directed acoustic radiation force impulse (ARFI) displacements up to 19 μm in a tissue-mimicking elasticity phantom. This demonstrates that miniature cylindrical transducers can be made to enable 360-deg elasticity imaging of the mechanical properties and structure of tissues, to identify vulnerable atherosclerotic plaques or quantify softening of the cervix prior to labor onset.
Using singular value distribution (SVD) of backscattered impulse response matrix to differentiate between low and high porosity in cortical bone
Authors: Yousefian Omid , Karbalaeisadegh Yasamin , Muller Marie M.
Published: November 2019

The goal of this study is to investigate whether singular value distribution (SVD) of the impulse response matrix can be used to differentiate between healthy and osteoporotic bone using backscattered signals from cortical bone samples ex-vivo. Two human cortical bone samples from the tibia were used, with a low (11% porosity, 64 μm average pore diameter, 17 pore/mm2) and high porosity (30% porosity, 105 μm average pore diameter, 14.73 pore/mm2). In order to take the effect of randomness into account, for each sample, three measurements at different locations of tibia were performed. The propagation matrix consisting of backscattered signals was collected by measuring the impulse response between each pair of elements of a linear array transducer (7.8 MHz central frequency). The singular value distribution of the propagation matrix in the frequency domain was evaluated for overlapping 0.5 μs time windows in the 6–9 MHz range. After normalizing, the probability density function of the SVD was evaluated and the strongest singular value was compared for low and high porosities. The results show a 20% difference on average for the largest singular value between high and low porosity, showing a potential of this method to differentiate between healthy and osteoporotic bone.
Simulated and experimental demonstrations of the first acoustic hologram enhanced phased arrays for manipulation
Authors: Cox Luke , Melde Kai , Croxford Anthony , Fischer Peer , Drinkwater Bruce W.
Published: November 2019

When attempting to form a desired static sound field for manipulation, acoustic holograms are generally superior to phased arrays due to their immensely higher resolution. However, they lack the dynamic capabilities of phased arrays. We therefore demonstrate a combination of the two. We produce several holograms for use with a continuously excited 64-element linear phased array. Simulations were used to predict the expected range of performance. We then experimentally demonstrate moving the position of the projected hologram plane via phase delays which tilt the output of the phased array. This creates a much more tightly focused point than the phased array alone, whilst retaining dynamical control. A second hologram allows the complex movement of a “phase surfer” along a phase track. These examples demonstrate that the strengths of both phased arrays and holograms can be combined. These developments open the door for more complex manipulation in the future whilst maintaining a relatively simple electronic set-up, thus reducing the cost whilst increasing the capability.
Assessing the cortical processing of spectrally rotated speech using functional near-infrared spectroscopy
Authors: Friedrichs Daniel , Steinmetzger Kurt , Clark Andrew , Rosen Stuart
Published: November 2019

Rotated speech (RS) is unintelligible to untrained listeners but contains similar temporal and spectral complexity as ordinary speech. It has been used in many studies to investigate cortical pathways for intelligible speech. Typically, the generation of RS involves the rotation of the spectrum of low-pass filtered speech around a center frequency (e.g., 2 kHz). Due to the inversion, voiced segments of RS contain harmonics that are typically not multiples of the fundamental frequency, and therefore the RS signal is not truly periodic. Here, it was assessed whether cortical responses to such aperiodic RS differ from quasi-periodic RS with preserved harmonic structure. Harmonic RS was constructed by rotating only the spectral envelope while preserving the characteristics of the source, whereas for inharmonic RS both components were rotated. A story listening paradigm was used, in which subjects were presented with 25-s blocks of unprocessed speech, inharmonic RS, and harmonic RS. Functional near-infrared spectroscopy (fNIRS) was used to measure cortical activation based on changes in the concentration of oxygenated and deoxygenated hemoglobin. The results show increased activity in the right posterior superior temporal sulcus (STS) for harmonic RS in comparison with inharmonic RS but not unprocessed speech. This demonstrates that the periodicity of RS should be considered in the interpretation of previous and the planning of future neuroimaging studies. [Wellcome Trust Multi-user Equipment Award and SNSF grant P400PG_180693.]
Word recognition and future language skills in 14-month-old infants
Authors: Bosseler Alexis , Tavabi Kambiz , Clarke Maggie , Larson Eric , Taulu Samu , Kuhl Patricia
Published: November 2019

Children show remarkable progress in word learning in the second year of life. This language growth coincides with the vocabulary spurt and the development of domain-general cognition, e.g., attention that facilitates perceptual processing. Evidence suggests that language growth depends on increasing processing efficiency and underlying neuronal specialization. We used magnetoencephalography (MEG) to characterize neural activity following familiar and unfamiliar words in 14-month-old infants and related measures of neural activity to prospective measures of vocabulary growth. MEG source modeling revealed a broadly distributed network in bilateral frontal, temporal and parietal cortex that distinguished word classes between 150–900 ms after word onset. Analysis of correlations between outcome measurements and strength of neural activity revealed that in the interval 150–300 ms after word onset, the magnitude of neural activation in the right inferior frontal cortex for familiar words was positively correlated with vocabulary size at 18, 21, 24, 27 and 30 months of age. We argue that increased activity to familiar words may reflect more efficient discriminatory processing by the most skilled language learners who develop a larger vocabulary one year later.
Accurate reading rate: Validations of machine scoring
Authors: Suzuki Masanori , Bernstein Jared , Cheng Jian , Okuda Tomoyo
Published: November 2019

Accurate oral reading rate is a common measure of early reading proficiency (grades K-4). A concurrent validation study compared a fully automated measure of accurate reading rate (words read correctly per minute) to DIBELS, a well-established, human-scored assessment. We report data from 174 students at a parochial school in Delaware and 130 students at a public school in Texas. Each student took three forms of an automatically scored test (yielding 898 test forms automatically scored) and also took the grade-appropriate form of the standard DIBELS test, which was scored by a trained person. Test administration order was counterbalanced. Correlations were computed for Machine-Machine and Human-Machine score pairs, for each grade separately and for the total dataset. When all grades are combined, Pearson r = 0.87, and correlations for single grades are all above 0.85, thus at or above the reliability ceiling of the DIBELS criterion score. Also, the automated tests have higher test-retest reliability (r = 0.91) than reported in an independent DIBELS study (Goffreda and DiPerna, 2010). [This research was supported by IES, U.S. Department of Education, via contract ED-IES-17-C-0030 to Analytic Measures, Inc. Disclosure: This report of an accurate automatic method may potentially benefit the authors financially in the future.]
Interpreting the latent representations of a convolutional neural network trained on spectrograms
Authors: Thomas Mark , Martin Bruce , Kowarski Katie , Gaudet Briand , Matwin Stan
Published: November 2019

Recent work [1,2] has shown that Convolutional Neural Networks (CNNs) trained on spectrograms of acoustic signals are capable of learning high-level latent representations for the purpose of detecting and classifying the vocalizations of endangered baleen whales. The aforementioned latent representations were used in the development of an automated system that was capable of detecting the vocalizations of blue, fin, and sei whales against non-biological and ambient noise sources to a high degree of accuracy (0.961, F-1 Score = 0.899). In this work, we conduct an exploratory analysis of the same latent representations using statistical machine learning approaches as well as by visualizing the convolutional feature maps learned by the CNN. Through this analysis we attempt to interpret what properties of a spectrogram are easily and/or most often exploited by the CNN during training in order to improve upon the state-of-the-art and develop more robust detection systems going forward. [1] M. Thomas, B. Martin, K. Kowarski, B. Gaudet, and S. Matwin, Marine Mammal Species Classification using Convolutional Neural Networks and a Novel Acoustic Representation, ECML PKDD 2019 (Springer, Cham, 2019). [2] M. Thomas, "Towards a novel data representation for classifying acoustic signals," in Canadian Conference on Artificial Intelligence (Springer, Cham, 2019).
Robust matched field processing for array tilt and environmental mismatch
Authors: Byun Gihoon , Akins Hunter , Song Hee-Chun , Kuperman William A.
Published: November 2019

Adaptive matched field processing with the minimum variance beamformer provides excellent sidelobe suppression for source localization, but suffers from sensitivity to mismatch between the modeled and true acoustic field (i.e., environmental mismatch). To increase tolerance to the mismatch while retaining satisfactory sidelobe control, robust algorithms such as the white noise constraint (WNC) can be employed. The WNC alone, however, is not sufficient when the mismatch results from an unknown array tilt (i.e., geometric mismatch). This study introduces an adaptive matched field beamformer that is tolerant to both array tilt and environmental mismatch. By modeling the pressure fields corresponding to a set of assumed tilt angles, we impose multiple constraints that, when applied to the beamformer, increase robustness to the array tilt. Simulations and data results are presented to demonstrate localization and tracking of a surface ship (200–500 Hz) using a 16-element, 56-m long, tilted vertical array in approximately 100-m deep shallow water.
Localizing underwater acoustic pingers using a streamlined method with an autonomous unmanned vehicle
Authors: Carline Emma , Wood Mark
Published: November 2019

Locating assets underwater is an important role of AUVs and Gliders. One instance is the recovery of black boxes from downed aircraft. All aircraft have an acoustic beacon attached to their flight data recorder that activates upon impact with water. Currently, to find the recorder a ship will search a large area towing a hydrophone while human operators carefully listen for the beacon’s pings. This is very costly! After searching the entire area, an estimate of the beacon’s location is made based on the loudness and spatial distribution of detections. Is this reliable? Is there enough time before the beacon’s battery dies? This talk presents a streamlined approach for locating pingers on the seabed. Here, an AUV replaces the ship, two hydrophones replace the towfish, and a small processor containing an automatic ping detector and localization algorithms replace human operators. The method exploits the AUV backseat driver in order to form synthetic hydrophone arrays and to diminish the search area after a ping is detected. Not only does this streamline the AUV’s route but also pinpoints the location of the blackbox from far away. The method will be introduced and results of field trials shown.
Calibration of marine differential pressure gauges through in situ testing at the seafloor
Authors: Doran Adrian , Rapa Martin , Laske Gabi , Babcock Jeff , McPeak Sean
Published: November 2019

Differential pressure gauges (DPGs) are a standard component of modern broadband ocean-bottom seismometer instruments and have proven useful for observing a wide range of seismic and oceanographic phenomena. However, the response function of the DPG remains poorly known, limiting our ability to recover amplitude and phase information from seafloor pressure signals with high fidelity. The sensitivity and long-period response are difficult to calibrate in the lab, as they are known to vary with temperature and pressure and perhaps between sensors of the same design. We present the results of a field experiment designed to determine empirical response functions in situ by inducing a pre-defined pressure offset on a deployed instrument. The results compare favorably with calibrations estimated independently through post-deployment data analyses. Our study demonstrates that observed response functions can deviate from the nominal response by a factor of two or greater with regards to both the sensitivity and the time constant. Incorporating calibration devices such as those described here into future deployments may prove to be a cost-effective way to improve the accuracy and utility of differential pressure data.
Validating passive acoustic methods for gas flux quantification, offshore Panarea, Mediterreanean Sea
Authors: Roche Ben , Li Jianghui , White Paul , Bull Jonathan M. , Davis John W. , Deponte Michele , Gordini Emiliano , Cotterle Diego
Published: November 2019

With the expected large scale adoption of carbon capture storage, a growing importance has been placed on developing methods for the detection and quantification of underwater gas releases in order to provide long term monitoring systems and assurance. Passive acoustic methods have strong potential, as a bubble larger than a few micrometers escaping from sediment into the water column produces a distinct acoustic signature, characterised by the Minnaert frequency. Building on this principle, Leighton and White (2012) devised a method for inverting the acoustic signature of a gas seep to determine its flux rate. However, until now little has been done to validate that passive acoustic gas inversion provides estimates that are consistent with other techniques, i.e., physical and optical measurements, in the field. A specialist acoustic-optical seabed lander was designed and deployed at a series of natural CO2 seep sites in offshore Panarea with the objective of comparing simultaneous flux estimates. Our results show that not only are acoustic estimates reliably consistent with all other methods but are also far more efficient.
Silver Medal in Physical Acoustics 2019: James M. Sabatier
Authors: Sabatier James M.
Published: November 2019

The Silver Medal is presented to individuals, without age limitation, for contributions to the advancement of science, engineering, or human welfare through the application of acoustic principles, or through research accomplishment in acoustics.
Machine learning challenges in bat biosonar
Authors: Müller Rolf , Goldsworthy Michael , Wang Ruihao , Zhang Liujun
Published: November 2019

Many bat species thrive in complex natural environments where their biosonar pulses trigger echoes with complex, unpredictable waveforms. In most cases, it remains unknown how the bats obtain sensory information they need from such clutter echoes. Machine learning methods that can extract relationships from large data sets could have a transformative impact on these research challenges. In particular, these methods hold considerable potential for answering the following questions: (i) What is the nature of biosonar echoes from complex environments; (ii) how can low-level navigation tasks such as contour-following and passageway finding be accomplished; (iii) what are acoustic landmarks for navigation and habitat selection; (iv) which clues exist for identifying prey in clutter; and (v) how does biosonar-based guidance in dense vegetation work at the system level? Machine learning methods are well suited for identifying models of echoes from complex vegetation that can be used to create large synthetic data sets with a known ground truth. Similarly, they can be employed to analyze (e.g., cluster) large physical echo datasets and to discover features associated with specific biosonar sensing tasks. Hence, machine learning could lead to the discovery of novel signal features to enable successful operation in much more complex environments.
Estimation of geoacoustic parameters using machine learning techniques
Authors: Potty Gopu R. , Miller James H , Michalopoulou Zoi-Heleni , Bonnel Julien
Published: November 2019

Modal dispersion of broadband acoustic data has been used extensively to estimate the geoacoustic parameters using perturbation techniques (Rajan et al., 1987), non-linear inversion techniques (Potty et al., 2000) and Bayesian inference (Warner et al., 2015). The Airy phase region corresponding the minimum group velocity of the normal modes are extremely sensitive to bottom properties in comparison with properties of the water column. This talk will explore the sensitivity of the group speed minima and the associated frequencies of the acoustic normal modes to bottom parameters. The group speed minima and the associated frequency data will be used to train a machine-learning algorithm. Synthetic data will be generated for various bottoms and it will be used as the training pool. Data collected from New England Bight, East China Sea, and New England Mud patch will be used to test the algorithm. The value added to the a priori bottom parameter information using the algorithm will be discussed in the context of computational cost associated with the algorithm. [Work supported by the Office of Naval Research.]
Investigating gradients in mud based on Bayesian modal-dispersion inversion and a hybrid geoacoustic model parameterization
Authors: Dosso Stan E. , Bonnel Julien , Chapman N. Ross , Wilson Preston S. , Knobles David P.
Published: November 2019

An important issue in understanding seabed geoacoustic properties at the site of the 2017 Seabed Characterization Experiment (SBCEX) on the New England Mud Patch is the extent to which gradients exist in geoacoustic properties (sound speed and density) over the upper mud layer. This paper applies Bayesian inversion and uncertainty quantification to modal dispersion data, resolved by warping analysis, to consider whether mud-layer gradients are required to fit the data. The inversion is based on a hybrid seabed-model parameterized in terms of an upper sediment layer with a general representation of smooth, continuous gradients in geoacoustic properties based on Bernstein-polynomial basis functions, above an unknown number of discrete layers formulated trans-dimensionally. The inversion results are compared to those from other acoustic data sets collected in the region as well as to nearby core measurements.
Bioeffects elicited by acoustic cavitation
Authors: Holland Christy K.
Published: November 2019

Ultrasound has been developed as both a diagnostic tool and a potent promoter of beneficial bioeffects for the treatment of cardiovascular disease and cancer. Ultrasound exposure can induce the release, delivery and enhanced efficacy of lytics, antibiotics, anti-inflammatory drugs or bioactive gases from echogenic liposomes. Other carriers for cancer therapeutics and small interfering ribonucleic acid (siRNA) and genes have also been developed. By encapsulating drugs and bubbles into micron-sized and nano-sized lipid-shelled particles, the therapeutic can be shielded from degradation within the vasculature until delivery is triggered by ultrasound exposure. The endothelial barrier between the bloodstream and vascular tissue presents a significant challenge to drug delivery. Most research on drug delivery from the blood vessel lumen into the tissue bed has been focused on blood-brain barrier disruption. Microbubbles oscillate when exposed to ultrasound and create stresses directly on nearby tissue or induce fluid effects that effect drug penetration into vascular tissue, lyse thrombi or direct drugs to optimal locations for delivery. Insonification accelerates clot breakdown in combination with a lytic and an ultrasound contrast agent, which nucleates sustained bubble activity. Mechanisms for ultrasound enhancement of clot dissolution, bactericide, and drug delivery, with a special emphasis on acoustic cavitation, radiation force and biological responses, will be reviewed.
Contrast enhanced diagnostic ultrasound induces capillary injury in rat intestine
Authors: Miller Douglas , Lu Xiaofang , Fabiilli Mario L. , Dou Chunyan
Published: November 2019

Contrast enhanced diagnostic ultrasound (CEDUS) can lead to microvascular injury through nucleation of cavitation. Capillary hemorrhage previously has been noted in heart, kidney, pancreas, and liver, which are common subjects of CEDUS examination. This research examined CEDUS injury of intestine. The abdomens of anesthetized rats were scanned by a 1.6 MHz diagnostic ultrasound probe during infusion of microbubble suspensions simulating the clinical ultrasound contrast agent Definity. Dual image frames were triggered intermittently, and the peak rarefactional pressure amplitude was varied to assess the exposure-response. Petechiae counts in small intestine mucosa and muscle layers increased with increasing trigger interval from 2 s to 10 s, indicative of a slow refill after microbubble destruction (cavitation nucleation). Counts increased with increasing output above a threshold of 1.4 MPa. Petechiae were also seen in Peyer’s patches, and occult blood was detected in many affected segments of intestine. For comparison, thresholds were 0.73 MPa, 0.95 MPa, 1.1 MPa, and 1.7 MPa in kidney, heart, pancreas, and liver. Threshold variation may be related to differences in capillary size (largest in liver) and blood refill time (1 s in kidney). Clinically, such bioeffects can be mitigated by avoiding contrast agent destruction.
Modeling a piezoelectric cantilever beam with Simscape
Authors: Childs Carter J. , Thompson Stephen C.
Published: November 2019

Previous work developed a lumped parameter model in Simscape for the transverse vibration of a thin bar [C. J. Childs and S. C. Thompson, J. Acoust. Soc. Am.  145, 1895 (2019)]. The current presentation expands that to include a layered bar, perhaps of different materials, and includes the electromechanical coupling for the case where the layers may be piezoelectric materials. This allows modeling such devices as the crystal or ceramic microphone that uses a piezoelectric bimorph element, and thin film piezoelectric cantilevers under consideration for vibration energy harvesting applications. While this paper uses Simscape for its examples, modeling these features in Modelica is equally possible.
Resolving bearing ambiguity with a single bio-inspired direction finding microelectromechanical system acoustic sensor
Authors: Gureck Brian , Rabelo Renato , Alves Fabio , Karunasiri Gamani
Published: November 2019

Microelectromechanical systems (MEMS) directional sound sensors have been developed to mimic the unique hearing mechanism of the parasitoid fly Ormia ochracea. The fly analyzes the superposition of the two natural oscillation modes (rocking and bending) of its coupled eardrums to identify the incident direction of a cricket chirp. The incident sound generates unequal oscillation amplitudes of the eardrums depending on the direction of incidence. The MEMS sensor consisted of two wings connected by a bridge which is attached to a substrate using two torsional legs. For electronic readout of the oscillation amplitude of the wings, a comb finger capacitor was integrated to each wing. The amplitudes of oscillation of the two wings were independently measured to probe the coupling between the rocking and bending modes. The measurement of the sensor response was performed optically, using a scanning laser vibrometer, and electronically using a capacitance to voltage converter. It was found that the oscillation amplitudes of the two wings are strongly affected by the incident direction of sound. In addition, higher wing deflection occurred on the side closest to the incident sound source indicating the ability of the sensor to detect the direction of sound without the right-left ambiguity.
MEMS directional acoustic sensor with charge amplifier based electronic readout
Authors: Rabelo Renato , Alves Fabio , Karunasiri Gamani
Published: November 2019

MEMS acoustic sensors based on the operating principle of the Ormia ochracea fly provide a unique way to determine the direction of sound. A typical sensor consists of two wings coupled by a bridge and the entire mechanical structure attached to a substrate using two torsional legs. The sensor mechanical structure has two different vibration modes which can be coupled by placing their resonant frequencies close to each other. The acoustic wave impinging on the sensor induces displacements which are detected using comb finger capacitors at the edges of the wings. Previously, this has been accomplished using the universal capacitive readout MS3110, which is prone to static variations of the comb finger capacitors. In this work, a charge amplifier circuit was developed to independently measure the displacements of the wings under sound excitation. The ability to simultaneously read these displacements is needed to determine the bearing of sound using a single MEMS sensor, in contrast to previously reported works that needed either a calibrated microphone or a second MEMS sensor to determine the incident sound pressure level. Measurements showed that both the phase difference and amplitude difference of oscillating wings were strongly dependent on the incident angle of sound.
Piezoelectric pressure sensors for hypersonic flow measurements at high-temperatures
Authors: Seo Yoonho , Kim Donghwan , Hall Neal A.
Published: November 2019

We present a microelectromechanical-systems (MEMS) piezoelectric pressure sensor designed for hypersonic flow measurements at extreme temperatures (>1000 °C). The sensing diaphragms have 700-μm diameter and are surface- and bulk-micromachined. The sensor employs aluminum nitride as a sensing layer due to its capability for high-temperature operation. We present the latest measurement results from a Ludwieg Mach-6 quiet tunnel, where prototype sensor data are compared against data from a state-of-the-art commercial sensor present in the same test. The prototype captures salient features of hypersonic flows including shock waves and second-mode instabilities indicative of laminar-to-turbulent transition. The prototype sensor also demonstrates superior signal-to-noise ratio in many test conditions. Prototypes have also demonstrated high-temperature operation by capturing audio while immersed in a butane flame (∼1200 °C).
A comparison on sound quality of PLA 3-D printing Ukulele and single board wooden Ukulele
Authors: Niu Xiaoyu , Qian Peng , Lin Shanru , Yu Shumeng , Fu Shengxue
Published: November 2019

With the development of science and technology in the 21st century, 3-D printing has made great progress. In the field of musical field, a complex sound source can be printed with the assistance of 3-D printing techniques. For example, the world's first Ukulele was printed out before long. Base on the innovation, we intend to compare and measure of the 3-D printing Ukulele and wooden Ukulele. Consequently, A-weight sound level of PLA 3-D printing Ukulele is less than that of traditional wooden with the same size, indicating that wooden resonant box is better at sound radiation than PLA 3-D printing Ukulele does. What's more, in the frequency domain, the fundamental frequency is higher than that of PLA 3-D printing Ukulele. In addition, in order to explain the difference between PLA 3-D printing Ukulele and wooden Ukulele, we simulate the vibrating state of two kinds of Ukulele with COMSOL. As a result, radiation acoustic impedance calculated by COMSOL could illustrate the difference. Hence, it is significant for musical instruments concerning the influence of material science.
From speech to songs via recital—A case of phase transition? A fractal study of Tagore’s work
Authors: Banerjee Archi , Patnaik Priyadarshi
Published: November 2019

This work explores the variation of scaling exponents in a song, recitation, and reading with the same lyrical content. Detrended Fluctuation Analysis (DFA) has been employed to find the long range temporal correlations (or the Hurst Exponent) present in each form of the auditory signal. Perceptually, it is known that the addition of rhythm and pitch, amplitude modulation distinguish between these different forms of audio signals, but the mathematical analogue of the same is still unknown. In this work, recordings were taken for 2 artists (1 male, 1 female) who were asked to read, recite and sing the entire lyrics of two (2) self chosen Tagore songs, each of which were later put to analysis. The rationale behind choosing Tagore’s works is because of its strong lexical content. It was seen that Hurst Exponent is found to be the lowest in case of reading while it maximizes in case of song implying that the amount of long range correlation increases consistently with addition of rhythmic content and pitch, amplitude modulation in the audio signals. With this work, we tried to establish a critical value of Hurst exponent, above/below which transformation occurs to other forms analogous to critical temperature in phase transition of matter.
Mathematical music theory of embodied acoustics of Ikoro music using beat-class theory
Authors: Calilhanna Andrea , Onwubiko Stephen G.
Published: November 2019

Through mathematical representation (beat-class theory) of embodied acoustics (psychoacoustics) the predominance of the musical tradition of the Ikoro drum with the Igbo’s can be traced from the past, into the present and forecasted into the future. The Ikoro music tradition has been viewed as an integral and indispensable part of Igbo culture at large (Onwubiko and Neilsen, 2019). The major musical instruments that accompany most Igbo music are percussional, such as, ichaka (beaded-gourd rattle), okpokolo (wooden claves), and igba (membrane drum) and are characterized by successions of rhythmic interchange unlimited to interesting pitch, timbre, rhythm and meter by employing shifted accents, non-accented rhythms and syncopations. In order to understand Ikoro music located in the listener’s experience (embodied psychoacoustics), we demonstrate how mathematical music theory (beat-class theory) provides the means to articulate the “mind and body” response to the stimulus of sound. By examining the aural tradition of Ikoro music of the Igbo’s through visualizations and sonifications of beat-class theory using ski-hill graphs and circular cyclic graphs, “hidden” musical structures are revealed which possess significant cultural significance.
Broadband superabsorption of waterborne acoustic waves by bubble metascreens
Authors: Lanoy Maxime , Leroy Valentin , Squire Steven , Strybulevych Anatoliy , Guillermic Reine-Marie , Lee Eric J. , Lemoult Fabrice , Tourin Arnaud , Page John H.
Published: November 2019

Absorption of acoustic or mechanical waves is an important challenge for various applications such as noise insulation, stealth coating, seismic event mitigation and ultrasonic testing. In order to absorb sound, one needs to introduce a medium with sufficient dissipation but without significant reflection of the incoming wave. Ideally, the absorber should also be thin and light, a goal that may be realized through the use of a thin 2-D metamaterial, or metalayer. The conventional way of achieving strong absorption in a thin metamaterial is to exploit low-frequency resonant inclusions. However, most resonant structures have an intrinsically narrowband response, making it difficult to attain broadband absorption in a deeply subwavelength-thick meta-layer, and making it necessary to devise larger structures to increase the bandwidth. For waterborne acoustic waves, an exception to this common situation can be achieved through the fabrication of bubble metascreens, which consist of a single layer of bubble inclusions embedded in a soft solid. In this presentation, we re-visit the optimization of such bubble metascreens and show that, despite being resonance-based, near-perfect absorption is possible over a very wide frequency range even when the metalayer is ultrathin.
Non-Hermitian complimentary acoustic metamaterials for imaging through skull
Authors: Craig Steven R. , Welch Phoebe J. , Shi Chengzhi
Published: November 2019

Complimentary metamaterials are designed to facilitate full acoustic transmission through highly mismatched impedance barriers. Applied to biomedical acoustics, complimentary metamaterials theoretically enable unidirectional acoustic transmission through the skull to realize noninvasive brain imaging and facilitate neural ultrasound therapies. Previously designed complimentary acoustic metamaterials relied on the realization of negative material parameters opposite to that of the skull to cancel the impedance mismatch effect. However, much of the incident acoustic energy is dissipated due to the skull’s internal porosity, preventing full energy transmission. To resolve this issue, we propose to counteract the skull’s acoustic attenuating effects with a non-Hermitian complimentary metamaterial (NHCMM) having an active gain circuit to achieve high acoustic transmission at high frequencies. In addition to the full wave simulations showing near perfect transmission from either side of the skull, the NHCMM preserves imaging information for objects inside the skull, and enhances the focused acoustic energy used for focused ultrasound therapies. By facilitating two-way acoustic transmission through the skull with NHCMMs, we lay the foundation for noninvasive brain imaging and treatment for neural disorders.
Efficient, wide-band coupled structural-acoustic computations combining time and frequency domain finite elements/equivalent sources
Authors: Fahnline John B.
Published: November 2019

Time and frequency domain computations are complementary, and here, the overall goal is to combine them to generate wide-band solutions of coupled structural-acoustic problems. Modal frequency response computations are efficient for low frequencies but become inefficient as the number of basis functions required to represent the response grows large. Modal formulations are required for large problems because the coupled equation system becomes densely populated when acoustic pressure forces are included. In contrast, the equation system remains sparsely populated in time domain formulations when the time step size is chosen appropriately, allowing large problems to be solved efficiently in terms of nodal degrees-of-freedom. However, the analysis times depend linearly on the number of time steps and a large number are generally required to represent the ringing response of low frequency modes. Here, the number of time steps is limited by applying an exponential taper to the time domain solution and truncating the computations. This reduces leakage effects, but does not affect components of response that have damped out before it is applied. Examples are given to illustrate the computations and the tradeoff between number of basis functions in the modal frequency response computations and number of time steps in the transient analyses.
Comparison between finite element and hybrid finite element results to test data for the vibration of a production car body
Authors: Vlahopoulos Nickolas , Sander David
Published: November 2019

The Hybrid Finite Element Analysis (Hybrid FEA) method is based on combining conventional Finite Element Analysis (FEA) with analytical solutions and energy methods for mid-frequency computations. The method is appropriate for computing the vibration of structures which comprises stiff load bearing components and flexible panels attached to them and for considering structure-borne loadings with the excitations applied on the load bearing members. In such situations, the difficulty in using conventional FEA at higher frequencies originates from requiring a very large number of elements in order to capture the flexible wavelength of the panel members which are present in a structure. In this presentation a three-way comparison will be offered for the vibration of a production vehicle body in the frequency range 200 Hz–1000 Hz. Six different excitation locations are utilized (one at a time); for each excitation the mobility of five reference body points on the load bearing members, and the mobility of eight flexible vehicle panels is measured and the measurements are compared with both conventional FEA results and with Hybrid FEA computations. Discussion about the development of the Hybrid FEA model and the correlation of both numerical solutions to the test data will be presented.