bluuebunny/crossref_metadata_2025 huggingface dataset:
Perfluorobutane phase shift nanoemulsion enables cavitation-mediated nonthermal ablation of brain tumors in rat
Authors: Peng Chenguang , Power Chanikarn , Sun Tao , Vykhodtseva Natalia , Zhang Yongzhi , Porter Tyrone M. , McDannold Nathan
Published: November 2019

Ultrasound nonthermal ablation is an emerging noninvasive technology for transcranial ablation. Nonthermal ablation has been achieved previously through inertial cavitation of ultrasound contrast agents (UCA). However, it is possible to generate unwanted damage in pre-focal regions due to the presence of UCA throughout the beam path. We propose to use perfluorobutane phase shift nanoemulsions (PFB-PSNE) instead of MBs to limit cavitation-mediated damage to the focal region. PFB-PSNE consist of a lipid shell and a liquid perfluorobutane core which can be vaporized and nucleate inertial cavitation using ultrasound. In this study, we demonstrated PFB-PSNE facilitated ablation in rat brain tumor. Four Fischer rats were implanted with F98 glioma in the caudate putamen. Two rats were sonicated with PFB-PSNE, and the other two served as controls. The tumors were sonicated 8 days after tumor implantation, and the animals were sacrificed at day 13 to harvest the brains. The tumor growth was evaluated with magnetic resonance imaging and histology. Localized microhemorrhage and ischemia was observed in the targeted tumors. We did not observe effects in the beam path. In summary, this work demonstrates the feasibility of using activated PFB-PSNE to produce localized cavitation sources that result in controlled damage in a glioma model.
Extra-wide-angle parabolic equation for wave propagation in inhomogeneous media
Authors: Ostashev Vladimir E. , Wilson D. Keith , Muhlestein Michael , Shaw Michael , Swearingen Michelle E. , McComas Sarah
Published: November 2019

To describe wave propagation at large angles with respect to a nominal direction, wide-angle parabolic equations (WAPEs) have been widely used in atmospheric and ocean acoustics, geophysics, electromagnetic wave propagation, and other fields of physics. This paper considers an application of an extra-wide-angle parabolic equation (EWAPE) for such problems. For small variations of the refractive index of a medium, the EWAPE describes wave propagation up to 90 deg with respect to the nominal direction and is more general than the WAPEs used in the literature. The EWAPE can be written in an integral form or as a pseudo-differential equation and may be solved by a split-step spectral algorithm or the Padé series expansions of the pseudo-differential operators. The EWAPE is also generalized to large variations in the refractive index, sound propagation above an impedance boundary, and a moving medium with small or large Mach numbers. For sound propagation in a moving medium, the EWAPE enables derivation of new WAPEs which are accurate and simpler to implement than those currently available in the literature. Numerical examples illustrating the application of these new WAPEs to sound propagation in a moving atmosphere are presented.
Choosing a textbook for the way your students learn
Authors: Piacsek Andrew A.
Published: November 2019

This presentation describes the challenges, opportunities, and lessons learned in the selection and use of textbooks for a 10-week course in acoustics for undergraduate physics majors at the junior or senior level at Central Washington University. This course emphasizes both theoretical and experimental skills; topics include damped harmonic systems, vibration in strings, bars, and membranes, plane and spherical wave propagation in air, and basic geometric acoustics. Two textbooks are employed for this course: the recently published "Understanding Acoustics" by Steve Garrett and the fourth edition of "Fundamentals of Acoustics" by Kinsler and Frey, revised and extended by Coppins and Sanders. Although both cover essentially the same topics, they have different attributes that facilitate learning at the undergraduate level. They are supplemented by online materials, interactive simulations, and journal articles. Examples of how these texts are used, and assessments of their efficacy, will be discussed.
Investigating the connection between physics and music in an introductory acoustics course
Authors: Linz Jill A.
Published: November 2019

Sound and music is an introductory acoustics course offered at Skidmore College in Saratoga Springs, NY. The target audience is primarily non-science majors fulfilling their math and science requirements. Over the span of its 25 + year history it has regularly attracted students interested in majoring in music technology and acoustics. Emphasis of the course is placed on the physics of music and music theory with attention paid to the interconnection between atomic physics and music. Fourier’s Theorem is used in making this connection. Sound editing programs such as Amadeus allow students to visualize recorded or synthesized sounds, and then analyze their spectra using Fourier analysis. Most course activities have been developed in accordance with Physics Education Research techniques and are designed using a discovery-based approach. Several activities from Sound & Music were recently highlighted in an article published online by Physics Today titled Composing Atom Music. Although Rossing, Moore & Wheeler’s The Science of Sound is the primary text, course materials are drawn from numerous sources. This presentation will focus on the course design, how the text book is used and will discuss the design and implementation of sample class activities.
Comparative studies on lift-off acoustic environments among flight data of the H-IIB launch vehicle, sub-scale acoustic tests and numerical simulations
Authors: Mori Ayano , Sarae Wataru , Terashima Keita , Tsutsumi Seiji , Takegoshi Masao , Kobayashi Hiroaki
Published: November 2019

A 1/42-scale acoustic tests were conducted to predict the lift-off acoustic environments of the H3 launch vehicle currently under development in Japan. The H3 acoustic level is estimated by relative comparison among sub-scale acoustic tests of the H3 / the H-IIB and flight data of the H-IIB. In this presentation, comparative studies between sub-scale tests and full-scale flight data for the H-IIB have been conducted as well as overall sound pressure level. CFD numerical simulations were also conducted to comprehend the phenomena. These provide further confidence that the sub-scale acoustic tests can favorably be used to verify the H3 lift-off acoustic environments.
Analysis of an underwater elastic leaky wave antenna
Authors: Haberman Michael R. , Spratt Kyle , Lee Michael , Naify Christina J.
Published: November 2019

An acoustic Leaky Wave Antenna (LWA) is an electronically simple device that enables frequency-dependent directional sound radiation or reception by coupling a single acoustic transducer to an analogue dispersive waveguide. While most acoustic LWA have focused on airborne acoustic waves, the successful demonstration of acoustic LWA in the underwater environment has been limited to recent numerical and experimental work by the authors [J. Acoust. Soc. Am., 145(3), 1727 (2019)]. In that work, the LWA was designed through ad hoc iteration of finite element (FE) models which is computationally expensive and therefore does not allow for efficient design space exploration. This work will present the derivation of an approximate analytical lumped parameter model for a one-dimensional underwater acoustic LWA consisting of an elastic bar containing periodically arranged mass-in-cavity inclusions. The analytical model employs long-wavelength expansions of sinusoidally forced continuous elements, resulting in a lumped-element approximate model that can be represented with an equivalent circuit. The lumped parameter approximation is compared with FE results and then used to make improvements on the previously reported LWA design.
Comparison measurements of homogenized material properties of underwater acoustic metamaterials
Authors: Beck Benjamin , Hanford Amanda
Published: November 2019

A current area of research interest in acoustic metamaterials is the experimental validation of the effective properties computed using analytical and numerical models. This is generally done through an inverse measurement technique, by measuring the reflective and transmitted wave amplitudes and phases to calculate an effective impedance. When the background fluid used for this measurement is air, either an impedance tube or anechoic chamber can be utilized for these measurements. However, if the application of the metamaterial is for in-water applications, the measurement of these properties becomes much more difficult due to many complicating factors. Therefore, there has been little work obtaining homogenized, anisotropic material properties of underwater acoustic metamaterials. In this work, we present comparison of measurement methods of an acoustic metamaterial in an aqueous environment: a water-filled impedance tube and in a reverberant water tank. The metamaterial response will be predicted, and compared to the measurement in the impedance tube and reverberant tank. Additionally, trade-offs between the two experimental methods will be given.
Can pitch rating methods converge on the frequencies within tonal stimuli?
Authors: Lentz Jennifer
Published: November 2019

This study evaluates whether a pitch rating method (sometimes used to assess tinnitus pitch) converges on the frequencies present in objective tonal stimuli. Twelve normal-hearing subjects completed a pitch rating experiment for seven test stimuli: 6 pure tones ranging from 0.5–12 kHz and two complex tones, with the 0.5-kHz tone used as practice. Subjects listened to 13 different comparison stimuli (presented in random order three times) and rated the similarity of the comparison stimuli to the test stimuli. Comparison stimuli were loudness-matched pure tones ranging from 0.5 to 16 kHz and were presented in an alternating sequence with the test tones. For pure tone test stimuli, results indicated a very high correlation between the highest-rated comparison tone and the test frequency, with slightly less fcorrespondence for the 12-kHz test stimulus. Matches between the ratings of comparison stimuli to complex tone spectra were not as robust, but generally speaking matched in bandwidth. Consequently, this method may be a useful tool for estimating the frequencies present in pure tone stimuli and possibly the bandwidth of complex tones. In comparison to our previous work, we found that both the low-frequency practice stimulus and the alternation of stimuli were critical to obtaining accurate results.
Benefits of a smartphone as a remote microphone system
Authors: Tittle Stephanie , Thibodeau Linda , Panahi Issa M. , Codanda Chengappa Preethi
Published: November 2019

Remote microphone (RM) systems have been shown to reduce the challenges hearing aid users face with communicating in noisy environments. The RMs worn by the speaker stream their voice wirelessly to the users’ hearing aids which results in a significant improvement in the signal-to-noise ratio. Given that the additional cost of a RM may not be feasible for some individuals, the possible use of applications on a smartphone has been explored. The Apple iPhone has an application called ‘Live Listen’ (LL) that can be used as an RM with made for iPhone hearing aids. The Statistical Signal Processing Research Laboratory at The University of Texas at Dallas has developed an open-source smartphone application for the iPhone that is also designed to be used as an RM. The purpose of this study was to compare the benefit of LL and the open-source app for participants with and without hearing loss on sentence recognition tasks in noise when listening through Starkey Halo2 hearing aids connected to an iPhone 7. Similar improvements in speech recognition were noted for both LL and the open-source app.
The cross-domain entrainment effects from pure tones to speech perception
Authors: Cheng Tzu-Han , Creel Sarah
Published: November 2019

Temporal context influences how humans perceive the durations of acoustic events. One of the most influential frameworks, proposed by McAuley and Jones (2003), suggests that entrainment is the underlying mechanism of timing estimation at short time durations. However, their approach has predominantly been tested on simple, music-like acoustic stimuli (e.g., pure tones). This raises the question of whether the same temporal context mechanisms are operative in other, more complex acoustic domains such as speech sound perception, which some have claimed to operate in modular fashion. In the current study, we first replicated McAuley and Jones (2003) and demonstrated an entrainment effect in our Experiment 1. Based on this finding, we extended the paradigm to the speech domain. In Experiment 2, we tested if an entrainment effect from a series of pure tones could influence the categorization of voiced (/ba/) and voiceless (/pa/) stop-initial syllables, which were created by varying the durations of voice onset time. Our findings suggest that entrainment from pure tone contexts may influence speech sound categorization. Data from these and ongoing studies has the potential to reveal a general mechanism of short-duration entrainment that can explain temporal context effects on timing perception in acoustically diverse domains.
Extracting beat from a crowd of loosely coupled, concurrent periodic stimuli
Authors: Lem Nolan V. , Fujioka Takako
Published: November 2019

In a musical ensemble, performers try to synchronize to a governing tempo by resolving differences in sound-onset timing from individual players even without a conductor's cue. Listeners and players alike must construct an internalized sense of when the beat occurs and adapt to that information dynamically as the performance goes on. Here, we examined this process by simulating individual sound onset timings with an ensemble of 40 virtual “metronomes” around 90 bpm with which we asked listeners to tap along for an approximately 10-beat duration. We manipulated coupling strength at five levels (very-weak, weak, medium, strong, perfect) where stronger coupling corresponds to a more definitively periodic beat. The inter tap interval (ITI) from 8 subjects were analyzed in three segments of the trial duration [early (tap 1–3), middle (4–6), and late (7–9)]. Also, the phase coherence of taps between listeners was compared to the stimulus density. Stronger coupling resulted in more stable ITI, while ITI became shorter in later segments for the medium and weak conditions. Interestingly, taps coincided with the greatest stimulus density for weaker coupling, whereas taps led ahead for stronger coupling. The results suggest that listeners could maintain a collective beat perception but less anticipatorily for less-synchronized sounds.
Cue weighting in the perception of Tagalog stress
Authors: Hwang Hyun Kyung , Nagaya Naonori , Villegas Julián
Published: November 2019

Relative importance of different acoustic cues in perceived prominence is language specific. In Tagalog, it has been argued that there is a lexical level stress, and a stressed syllable exhibits higher fundamental frequency, longer duration, and stronger intensity (Gonzales, 1970). Still, the relative weight of these cues has not been discussed in the prosodic literature. The purpose of the current study is to quantify the relative weighting of multiple acoustic cues in the perception of lexical stress in Tagalog. A forced-choice identification test was conducted with a disyllabic word /babad/. Each of the three acoustic cues in both syllables was manipulated in two levels, i.e., strong and weak, under fully crossed combinations of the cues. A total of sixty-four stimuli were tested in four sessions, and fifty-three native speakers of Tagalog participated in the test. The result of a generalized linear model using a binomial distribution revealed that the primary perceptual cue is duration. Longer duration was significantly associated with perceived prominence, and higher fundamental frequency to a lesser degree. However, intensity cues did not seem to play a significant role in stress perception in Tagalog.
The effects of high variability training on voice identity learning
Authors: Lavan Nadine , Knight Sarah , Hazan Valerie , McGettigan Carolyn
Published: November 2019

High-variability training has been shown to benefit the learning of phonetic contrasts and new face identities. Here, we investigated whether high-variability training also aids voice identity learning. In Experiment 1, we contrasted high variability training (including stimuli extracted from several different recording sessions and speaking styles) with low variability training (including stimuli extracted from one recording session of read sentences; i.e., one speaking style). Listeners learned to recognise 4 voice identities (2 through high-variability training, 2 through low-variability training) and were subsequently tested on an old/new recognition task using novel read sentences. We found no high-variability training advantage in Experiment 1 – instead we found a high-variability disadvantage. However, in this experiment there was full overlap of speaking style in the low variability voices across the two task phases. We therefore ran a second experiment (Experiment 2), in which test stimuli were sourced from a previously unheard speaking style: The manipulation of high versus low-variability training was otherwise achieved in the same way as before (many speaking styles versus one speaking style). In this experiment, we observed a high-variability advantage. Findings are discussed in the context of the mechanisms thought to underpin advantages for high-variability training.
Factors shaping vowel perception biases in adults
Authors: Liu Ying Ying , Masapollo Matthew , Menard Lucie , Polka Linda
Published: November 2019

Vowel discrimination is often asymmetric such that discriminating the same vowel pair is easier in one direction compared to the opposite direction. The Natural Referent Vowel framework interprets these directional asymmetries as a universal bias favoring “focal” vowels (i.e., vowels with prominent spectral peaks formed by the convergence of adjacent formants). The Native Language Magnet model instead interprets asymmetries in terms of a language-specific bias due to distortion of perceptual space around native language vowel prototypes. To test these competing views, Masapollo et al. (2017) compared English- and French-speaking adults’ discrimination of synthetic /u/ variants; this was informative because English /u/ is naturally less focal than French /u/. Their findings revealed asymmetries to be predicted by focalization only; although stimulus limitations may explain the lack of prototype effects. Here, we synthesized a more refined series of vowel stimuli systematically varying in smaller psychophysical steps around the English /u/ and French /u/ prototypes to augment the measurement of focalization and prototype effects. Native English speakers completed a category goodness-rating task followed by an AX-discrimination task using these new variants. Results indicated effects of both focalization and prototype, which are moderated by the size of acoustic intervals along the stimulus series.
Lexically dependent estimation of acoustic information in speech III: Cross-splicing verification of cue weights
Authors: Redmon Charles , Jongman Allard
Published: November 2019

In two prior studies (Redmon and Jongman, 2018, 2019, JASA), results of open- and closed-class word recognition tasks on items drawn from a large single-speaker database (Tucker et al., 2018) were used to train a model where acoustic cue weights were optimized to distinguish words in the lexicon, rather than a balanced inventory of phones. From that work, cues were identified that had a greater weight when considering the lexicon as a whole than when studying a symmetric set of contrasts in controlled syllable productions. To verify the causal role of such cues in word recognition, two new cross-splicing versions of the open- and closed-class tasks were run with a subset of items in each prior experiment. In each, an enhancement condition was created by cross-splicing diphones from items in the database with more distinct values on a given cue dimension, and consequently greater model-predicted accuracy. For each such item, a parallel reduction condition was created wherein accuracy was predicted to decrease due to the cross-splicing of a diphone with a more ambiguous value of a given cue. Results will serve to validate the relative role of the different cues in a manner that is external to the model-fitting procedure.
Biphone probability and neighborhood density effects on phonetic categorization
Authors: Steffman Jeremy , Sundara Megha
Published: November 2019

Adults’ categorization of speech sounds is influenced by different aspects of lexical and phonological organization. These include neighborhood density and biphone probability. The role of both these influences in models of speech recognition has been a topic of debate. This is in part because these two effects are difficult to disambiguate given the measures are highly correlated: denser neighborhoods tend to have high biphone probability sequences. Accordingly, interactive models can account for neighborhood density effects based on lexical feedback, with biphone probability effects as their by-product. Conversely, in the absence of feedback from the lexicon, autonomous models can explain density effects using biphone probabilities alone. We present two experiments testing cases which disambiguate these effects. In Experiment 1, listeners categorized re-synthesized /ɛ/∼/æ/ continua. Vowel continua were presented in CVC frames, both endpoints of which were English non-words. Crucially, we manipulated the neighborhood density and biphone probabilities of each endpoint of the continuum independently. Our results show an independent contribution of neighborhood density and biphone probability in categorization. In Experiment 2, we are now using eye-tracking to disentangle the time course of each effect. Results will be discussed in the context of the role of feedback in speech recognition.
The role of semantic predictability in adaptation to non-native-accented speech
Authors: Walker Kayla , Baese-Berk Melissa M. , Bent Tessa
Published: November 2019

Non-native-accented speech is more difficult for native listeners to understand than native-accented speech. However, listeners can improve their abilities to understand nonnative—accented speech through exposure and training. The goal of this project is to explore whether exposing native listeners to different sentence types affects listeners' adaptation to non-native speech. Listeners will be trained on high predictability sentences (e.g., “The color of a lemon is yellow”), low predictability sentences (e.g., “Mom said that it is yellow”), or semantically anomalous sentences (e.g., “The green week did the page”). Previous research has demonstrated that semantic predictability impacts speech perception, but its influence on adaptation to nonnative speech is unknown. Will training with low predictability or anomalous stimuli require listeners to focus more attention on the acoustic-phonetic properties of the accent and thus lead to greater adaptation and generalizable learning? Or will training with high predictability stimuli provide valuable semantic information that will allow listeners to create a better framework for improving perception? The data from this experiment will shed light on perceptual mechanisms, including how semantic predictability interacts with adaptation and learning.
Comparison and real-time implementation of fixed and adaptive beamformers for speech enhancement on smartphones for hearing aid study
Authors: Shankar Nikhil , Shreedhar Bhat Gautam , Panahi Issa M.
Published: November 2019

In this paper, we compare the performance of fixed and adaptive beamformers as an application to speech enhancement (SE) algorithm. The proposed signal processing pipeline works in real-time for hearing aid devices using a smartphone as an assistive tool. The proposed method consists of a Wiener filter based single-channel SE method along with beamformer as a pre-filter. In this work, multiple beamforming approaches like delay and sum, minimum variance distortionless response (MVDR) and generalized sidelobe canceller (GSC) beamformers are considered and compared. The use of beamformers is shown to improve the signal to noise ratio (SNR) in real-world noisy conditions through the results presented in this paper. Objective, intelligibility evaluation, and subjective test results show the comparison and efficiency of the proposed method at different SNR levels.
Experimental study on source direction finding using a cylindrical array considering scattered sound fields
Authors: Kim Sea-Moon , Lee Keunhwa , Choo Yeon-Seong , Byun Sung-Hoon
Published: November 2019

A circular array is widely used for source direction finding due to its more compact configuration and smaller angular dependency compared to a linear array. In underwater environments, however, high drag forces make it difficult to utilize the circular array especially for the case where there is high-speed ocean current or the platform with the array is moving. To overcome this operational difficulty an array of hydrophones flush mounted on a cylindrical structure may be applied. A recent numerical study shows that the beamforming performance is improved by considering the scattered sound field by a cylinder. Recently, a tank experiment using an array of eight receiver element on a cylindrical structure has been done for underwater source direction finding. In the experiment narrowband and wideband signals are used for the sound transmitter. The experimental results also show that the lower side-lobes are obtained when the scattering effect is considered during beamforming analysis. [This work is financially supported by the research project PES3180 funded by KRISO.]
Variability of radiated underwater noise measurements for a small research vessel in shallow water
Authors: Humphrey Victor F. , Brooker Alex
Published: November 2019

The increased interest in the potential environmental impact of noise from shipping is resulting in the development of measurement methods for determining the radiated noise level and equivalent monopole source level of vessels. It is important to understand the random and systematic uncertainties associated with such techniques. The EU SONIC project provided an opportunity to make repeated measurements on the University of Newcastle research vessel, the Princess Royal, in a shallow water environment (100 m deep) over a number of days. Two multiple hydrophone arrays operated by two of the project partners, CETENA and the University of Southampton, were deployed from the same moored support vessel. This data is reviewed to illustrate the variation associated with such measurements and the impact of using multiple hydrophones and multiple measurement runs on the uncertainty in the radiated noise level and the calculated source level. The results are also compared with a later measurements of the same vessel in a different shallow water environment (20 m deep) using bottom moored hydrophones.
Ship source levels in a National Marine Sanctuary
Authors: ZoBell Vanessa M. , Frasier Kaitlin E. , Wiggins Sean M. , Thayre Bruce , Hatch Leila , Hastings Sean , Peavey Lindsey , Hildebrand John
Published: November 2019

Ship noise in the ocean significantly contributes to low-frequency ambient noise. The Santa Barbara Channel is an ideal site to study noise from shipping because of the intense commercial vessel traffic travelling to the Port of Los Angeles and the Port of Hueneme. In response to concerns of increased ship noise in this area, the Channel Islands National Marine Sanctuary (CINMS) introduced a ship speed reduction program, in the hopes of reducing ship noise. In order to quantify source levels (SLs) of ships that participated in speed reduction, we compared source levels of 31 vessels that participated in the program with source levels of non-participating vessels over the same period. Recordings were made using a High-frequency Acoustic Recording Package at a depth of 580 m, approximately 3 km from the northbound shipping lane. For each ship passage, we measured received levels of passing ships in 1 minute intervals. Source levels (SLs) were calculated by accounting for transmission loss between the recording device and the ship locations obtained from Automated Identification System data. SLs quantified in this work will allow CINMS to evaluate the effectiveness of the speed reduction program for lowering noise inputs from vessels transiting through the sanctuary.
Seismoacoustic observations at deep ocean observatories: ACO, H2O, and OSN1
Authors: Butler Rhett
Published: November 2019

Deep seafloor (~5000 m) observations of seismoacoustic arrivals are presented from the Aloha Cabled Observatory (ACO), Hawaii-2 Observatory (H20), and Ocean Seismic Network-1 (OSN1). Acoustic observations of local earthquakes from the ACO 24 kHz hydrophone show extraordinarily high frequencies up to 165 Hz at distances to ~200 km—a unique window into earthquake source dynamics. Combined seismic and hydrophone observations show that the traditional T wave propagates as a seismoacoustic polarized interface wave “Ti” coupled to the seafloor. Seismoacoustic Ti waves propagating at the sound speed of water are routinely observed over megameter distances at H2O between Hawaii and California, even though the seafloor site is within the shadow zone for acoustic wave propagation. Internal waves or thermohaline covariation may or may not be sufficient to scatter acoustic energy from the SOFAR channel to the deep seafloor. Ti has also been observed on seismometers SSW of Oahu at the OSN1 site at the seafloor and within an ODP borehole 242 m into the basalt basement. The observation of Ti from an earthquake in Guatemala at OSN1, whose path is blocked by the Island of Hawaii, is consistent with scattering from the vicinity of the Cross Seamount.
On the possible role of gravity waves in the ocean in T-phase excitation by earthquakes
Authors: Godin Oleg A.
Published: November 2019

Recent applications of a time-domain spectral-element method to obtain full-wave solutions of seismo-acoustic problems by Bottero et al. [J. Acoust. Soc. Am., 144, EL222–EL228 (2018)] and especially their investigation of T-phases in the Mediterranean [Bottero et al., J. Acoust. Soc. Am., 141, 4045 (2017)] challenge the existing understanding of the mechanisms of seismic energy conversion into T-waves, which propagate at the speed of sound in water. Motivated by these results, this paper aims to evaluate the contribution of scattering by hydrodynamic waves into T-phase generation. Ocean is modeled as a range-independent waveguide with superimposed volume inhomogeneities due to internal gravity waves and surface roughness due to wind waves and sea swell. Guided acoustic waves are excited by volume and surface scattering of ballistic body waves. The size of the effective source of T-waves and their amplitudes are calculated in the single scattering—multiple reflections approximation. Efficiency of the gravity wave-mediated conversion of seismic energy will be compared to that of the conversion that occurs on a seafloor slope.
Acoustics of water entry of hydrophobic spheres
Authors: Rabbi Rafsan , Truscott Tadd , Allen John S. , Belden Jesse
Published: November 2019

Hydrophobic spheres form different cavities depending on the sphere size and the impact parameters. Cavities types have been investigated with respect to their interface characteristic, and regimes denoted as deep seal, surface seal, shallow seal, quasi-static seal, and rebound have been previously reported. The acoustic characteristics of these cavities have relatively unexplored compared with that of impacting liquid drops. A previously developed experimental setup for water entry visualization is extended for acoustic measurements. Simultaneous acoustic and optical measurements are done with the synchronization of a condenser air microphone and hydrophone with two high speed video cameras. Spheres of diameter 8–40 mm are investigated for corresponding impact velocities of 1.4–6.0 m/s. Room temperature metal spheres sprayed with Cytonix WX-2100 coated are compared with those heated up to the inverse Leiden temperature (120–440°C). In both cases, acoustic signature is found to be directly related to sealing phenomena. Upon impact, the heat spheres have a specific vaporization sound compared to the coated case. The transition and values of the Leiden frost temperature are investigated with respect to spectral acoustics signal features.
GHz ultrasound propagation with a high speed in compressible liquids containing many microbubbles
Authors: Akutsu Ryosuke , Yoshimoto Takanori , Kanagawa Tetsuya , Uchiyama Yusuke
Published: November 2019

This paper theoretically deals with weakly nonlinear (i.e., neither linear nor strong nonlinear) propagation of plane progressive quasi-monochromatic waves in an initially quiescent compressible liquid containing a tremendously large number of spherical gas bubbles on the basis of the derivation of two types of amplitude evolution equations (nonlinear wave equations). The important points are as follows: (i) the compressibility of the liquid phase, which has long been neglected, is taken into account; (ii) The incident wave frequency is very larger than an eigenfrequency of single bubble oscillations; (iii) bubbles are neither created nor annihilated; and (iv) the thermal effect is not considered and wave dissipation are then owing to liquid compressibility and liquid viscosity. By the use of the method of multiple scales with an appropriate choice of scaling relations of threenondimensional parameters, we can derive two types of the complex Ginzburg-Landau equations (or nonlinear Schrödinger equations), where the phase velocity is larger than the speed of sound in a pure liquid.
Immersive wave propagation experiments in a two-dimensional acoustic waveguide
Authors: Becker Theodor S. , Börsing Nele , van Manen Dirk-Jan , Haag Thomas , Donahue Carly M. , Curtis Andrew , Robertsson Johan O.
Published: November 2019

The physical implementation of immersive boundary conditions (IBCs) allows acoustic or elastic waves to propagate seamlessly between a physical domain, such as a wave propagation laboratory, and a numerical simulation virtually enclosing the physical domain. IBCs correctly account for all wavefield interactions between both domains, including higher-order long-range scattering. In this contribution, IBCs are physically implemented in a two-dimensional (2-D) acoustic waveguide. The boundary surrounding the waveguide is densely populated with hundreds of loudspeakers that apply the necessary boundary conditions. The required signals to be injected at the boundary are predicted in real-time by (1) measuring the pressure field and its gradient on two acoustically transparent auxiliary surfaces of microphones inside the waveguide and (2) extrapolating the wavefields to the boundary by evaluating a Kirchhoff-Helmholtz integral using a low-latency, FPGA-enabled data acquisition, computation and control system. Here, we demonstrate the first real-time, 2-D physical immersive wave propagation experiments. We present the setup, as well as a suite of experiments that demonstrate the ability of IBCs to actively suppress broadband incident fields at the boundary of the waveguide and to correctly reproduce all orders of wavefield scattering between the physical experiment and the numerical simulation.
Application of the fatigue damage spectrum to accelerated vibration testing
Authors: Touzanov Odissei , Guers Manton J.
Published: November 2019

Vibration testing is an important part of product validation in many industries. However, the time to conduct a vibration test is an important consideration, especially in industries where designs need to be validated quickly. In this work, the Fatigue Damage Spectrum (FDS) methodology was validated against results presented in the literature and then applied to a vibration test profile based on road load data. An experimental validation of the code was performed using an electrodynamic shaker. It was demonstrated that the FDS methodology can cut the testing time in half and produce reasonable results based on the criteria of maximum crack length of the specimens.
High bandwidth airborne acoustic detection system (HBADS) for circular synthetic aperture acoustic imaging of canonical ground targets
Authors: Bishop Steven S. , Moore Timothy R. , Gugino Peter , Smith Brett , Kirkwood Kathryn P. , Korman Murray S.
Published: November 2019

High Bandwidth Acoustic Detection System (HBADS) is an active acoustic sensor technology developed by the US Army’s Night Vision and Electronic Sensors Directorate. The stripmap airborne synthetic aperture acoustic (SAA) array (mounted on an all-terrane vehicle) contains two horizontal rows of eight evenly spaced microphones oriented in a side scan configuration. An audio speaker (located near the array center) transmits a linear FM chirp having a 2 kHz to 15 kHz effective bandwidth. Experiments are performed with the vehicle in motion to image canonical ground targets in clutter or foliage. A laptop computer controls the 16 channel data acquisition system. The system includes an inertial navigation system (two differential GPS antennas), a wheel coder, a camera, and a unit for measuring temperature, pressure, and humidity. Experiments include imaging spherical targets located on the ground in a grassy field and similar targets camouflaged by natural vegetation along the roadside using both stripmap SAR and circular path C-SAR radar-like configurations. Typical parameters are chirp pulse = 10 or 40 ms, slant range resolution c/(2*BW) = 1.3 cm (air sound speed c ≈ 340 m/s), microphone diameter D = 2 cm, (azimuthal resolution is D/2), and maximum vehicle speed ≈ 2 m/s.
Flexural vibration of steel beam with locally resonant phononic crystal: An experimental investigation
Authors: Cho Tongjun , Choi Jewoo , Bae Sang Geun , park Hyo Son
Published: November 2019

The effect of locally resonant phononic crystal on the bending wave propagation behavior of a full-scale steel beam structure was experimentally investigated. The unit cell of the phononic crystal was designed with a composition comprising a tungsten mass, a silicone rubber spring, and a plaster matrix. The vibration resonances of the coated tungsten sphere of the phononic crystal units were evaluated by an analytical model and experimental measurements. The frequency response functions of the beam structure indicated that modal energy of the bending wave vibration is significantly reduced due to the locally resonant mechanism of the attached phononic crystal units. The local resonance bandgap observed in the experiment suggest that phononic crystals can be used for a method of flexural vibration control of beam structures.
Tongue root configuration during Seoul Korean stops: An ultrasound study
Authors: Ahn Suzy , Kwon Harim
Published: November 2019

Tongue root advancement facilitates voicing during stop closure by enlarging the supralaryngeal cavity volume (Westbury, 1983). In a recent ultrasound study, Ahn (2018) reports that tongue is indeed more advanced during voiced than voiceless stops both in English and Brazilian Portuguese, suggesting that the articulatory adjustment aligns more with the abstract laryngeal distinctions than their acoustic implementation—the "voiced” stops are typically not phonated in English but in Brazilian Portuguese. This study, using ultrasound, compares tongue positioning during Seoul Korean (SK) stops of three laryngeal categories: lenis, fortis, and aspirated. All three categories are voiceless phrase-initially, with the lenis being voiced intervocalically (Jun, 1993). This study asks whether (1) SK lenis, fortis, and aspirated stops have different tongue configurations when none are phonated and (2) the intervocalic voicing of lenis stops leads to tongue root advancement. Nine native SK speakers recorded phrase-initial and intervocalic stops. Results: lenis, fortis, and aspirated stops did not show different tongue position in phrase-initial positions. In intervocalic positions, lenis stops, acoustically voiced during closure, did not show more tongue root advancement than other types of stops. These results suggest that SK speakers use tongue positioning neither for laryngeal contrast nor as an adjustment for allophonic voicing of intervocalic lenis stops.
Two applications of movable mandible for physical models of the human vocal tract
Authors: Arai Takayuki
Published: November 2019

The first application of a movable mandible for physical models of the human vocal tract is based on the 2017 static-model, the vocal-tract configuration of which was set to produce the vowel /a/. Two parts of the model, upper and lower jaws, are combined with a miniature robot hand unit to achieve articulatory movements for visual cues in a speech perception study. The second application is based on the 2018 dynamic-model, which is physically able to produce human-like speech sounds with a flexible material. Because portions of the articulators including the top surface of the tongue are made of a gel-type material, a user can manipulate the shape of the tongue and articulate different vowels and a certain set of consonants for educational purposes, for example. However, the mandible of the model is fixed, making it difficult to manipulate different sounds with different jaw openings, such as high versus low vowels. Therefore, a new model was developed by adding an additional mandible mechanism to the 2018 model. The mandible was designed to move between the open and closed positions by creating an arc-shape rail. As a result, various speech sounds with a flexible-tongue and movable mandible can be easily produced.
Pinpointing nitrogen oxide emissions from space
Authors: Beirle Steffen , Borger Christian , Dörner Steffen , Li Ang , Hu Zhaokun , Liu Fei , Wang Yang , Wagner Thomas
Published: November 2019

Power plant exhausts can be identified and quantified from satellite observations.
A heat-stable microparticle platform for oral micronutrient delivery
Authors: Anselmo Aaron C. , Xu Xian , Buerkli Simone , Zeng Yingying , Tang Wen , McHugh Kevin J. , Behrens Adam M. , Rosenberg Evan , Duan Aranda R. , Sugarman James L. , Zhuang Jia , Collins Joe , Lu Xueguang , Graf Tyler , Tzeng Stephany Y. , Rose Sviatlana , Acolatse Sarah , Nguyen Thanh D. , Le Xiao , Guerra Ana Sofia , Freed Lisa E. , Weinstock Shelley B. , Sears Christopher B. , Nikolic Boris , Wood Lowell , Welkhoff Philip A. , Oxley James D. , Moretti Diego , Zimmermann Michael B. , Langer Robert , Jaklenec Ana
Published: November 2019

A heat-stable microparticle platform improves oral micronutrient delivery.
A new hope? Yoda1 uses the “force” to sensitize cancer cells to TRAIL-mediated apoptosis
Authors: Weaver Jessica D.
Published: November 2019

A mechanosensitive ion channel agonist mimics shear stress to enhance the cytotoxic effects of TRAIL on cancer cells.
New Sipanmycin Analogues Generated by Combinatorial Biosynthesis and Mutasynthesis Approaches Relying on the Substrate Flexibility of Key Enzymes in the Biosynthetic Pathway
Authors: Malmierca Mónica G. , Pérez-Victoria Ignacio , Martín Jesús , Reyes Fernando , Méndez Carmen , Salas José A. , Olano Carlos
Published: November 2019

Combinatorial biosynthesis has proved its usefulness in generating derivatives of already known compounds with novel or improved pharmacological properties. Sipanmycins are a family of glycosylated macrolactams produced by
Streptomyces
sp. strain CS149, whose antiproliferative activity is dependent on the sugar moieties attached to the aglycone. In this work, we report the generation of several sipanmycin analogues with different deoxysugars, showing the high degree of flexibility exerted by the glycosyltransferase machinery with respect to the recognition of diverse nucleotide-activated sugars. In addition, modifications in the macrolactam ring were introduced by mutasynthesis approaches, indicating that the enzymes involved in incorporating the starter unit have a moderate ability to introduce different types of β-amino acids. In conclusion, we have proved the substrate flexibility of key enzymes involved in sipanmycin biosynthesis, especially the glycosyltransferases, which can be exploited in future experiments.
Staphylococcus aureus Isolated from Skin from Atopic-Dermatitis Patients Produces Staphylococcal Enterotoxin Y, Which Predominantly Induces T-Cell Receptor Vα-Specific Expansion of T Cells
Authors: Aziz Fatkhanuddin , Hisatsune Junzo , Yu Liansheng , Kajimura Junko , Sato’o Yusuke , Ono Hisaya K. , Masuda Kanako , Yamaoka Mika , Salasia Siti Isrina Oktavia , Nakane Akio , Ohge Hiroki , Kusunoki Yoichiro , Sugai Motoyuki
Published: November 2019

While investigating the virulence traits of
Staphylococcus aureus
adhering to the skin of atopic-dermatitis (AD) patients, we identified a novel open reading frame (ORF) with structural similarity to a superantigen from genome sequence data of an isolate from AD skin. Concurrently, the same ORF was identified in a bovine isolate of
S. aureus
and designated SElY (H. K. Ono, Y. Sato’o, K. Narita, I.
Dendritic Cells TargetingLactobacillus plantarumStrain NC8 with a Surface-Displayed Single-Chain Variable Fragment of CD11c Induce an Antigen-Specific Protective Cellular Immune Response
Authors: Liu Jing , Yang Guilian , Huang Haibin , Shi Chunwei , Gao Xing , Yang Wentao , Zhang Zan , Liu Yang , Xu Ke , Wang Jianzhong , Kang Yuanhuan , Jiang Yanlong , Wang Chunfeng
Published: November 2019

Influenza A virus (H1N1) is an acute, highly contagious respiratory virus. The use of lactic acid bacteria (LAB) to deliver mucosal vaccines against influenza virus infection is a research hot spot. In this study, two recombinantLactobacillus plantarumstrains expressing hemagglutinin (HA) alone or coexpressing aCD11c-HA to target HA protein to dendritic cells (DCs) by fusion to an anti-CD11c single-chain antibody (aCD11c) were constructed.
Revisiting groundwater carbon fluxes to the ocean with implications for the carbon cycle
Authors: Zhang Shuang , Planavsky Noah J.
Published: November 2019

Compared with riverine systems, the influence of groundwater on the global carbon cycle has remained underexplored. Here, we provide a new estimate of the bicarbonate fluxes from fresh groundwater to the ocean by coupling a statistical and hydrological analysis of groundwater and river samples across the contiguous United States with a study of global groundwater characteristics. We find that the mean concentration ([]) in groundwaters exceeds that in surface rivers by a factor of 2–3 throughout the contiguous United States. Based on estimates of fresh groundwater discharge to the ocean and scaling up our estimated mean [] in groundwaters from the United States and around the world, we arrived at a mean global flux from groundwaters ranging from 7.4 × 1012 (25th percentile)–1.8 × 1013 mol/yr (75th percentile) to 2.8 × 1013–8.3 × 1013 mol/yr, which is 22%–237% of the global flux from river systems, respectively. We also estimated that the global carbon flux derived from subsurface silicate weathering could be comparable to 32%–351% that from surficial silicate weathering, depending on groundwater discharge rates. Despite large uncertainties due to data limitation, this study highlights that groundwater weathering could be an important carbon sink in both the short- and long-term carbon cycle. Therefore, additional work on groundwaters is needed to develop a well-constrained view of the global carbon cycle.