bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a histotripsy array for the treatment of intracerebral hemorrhage
Authors: Gerhardson Tyler , Sukovich Jonathan R. , Lundt Jonathan E. , Lu Ning , Pandey Aditya , Cain Charles A. , Xu Zhen , Hall Timothy L.
Published: April 2019

Histotripsy is a focused ultrasound technique using short, high amplitude pulses to generate targeted cavitation. Recently, the feasibility to treat blood clots through human skulls with histotripsy has been shown in vitro. The purpose of this study was to evaluate acoustic parameters for developing an optimized array design for the treatment of intracerebral hemorrhage (ICH) with histotripsy. The main performance criteria were to achieve a large electronic focal steering range (≥ 20 mm) and an ability to correct aberration through the skull. A hemispherical aperture of 150 mm radius was considered with modular elements to allow for arbitrary insertion of a catheter hydrophone to perform aberration correction. The attenuation at discrete frequencies from 250 kHz–2 MHz was measured through excised human skulls (n = 7) along with effects of incidence angle and aberration to optimize the operating frequency. Different piezoelectric materials were tested to optimize the peak-output, transduction efficiency, and durability at high PRF. One of the best performers, 17 mm square PZ36 material at 700 kHz, was found to produce at least 1.5 MPa free field at PRFs of 1 kHz. Finally, simulation showed that an optimally packed array configuration using 360 modules should be able to achieve an effective steering range of at least ±20 mm through the skull.
Focused ultrasound-mediated microbubble destruction for glioblastoma treatment
Authors: Zhu Lifei , Nazeri Arash , Altman Michael , Thotala Dinesh , Sharifai Nima , Chen Hong
Published: April 2019

Glioblastoma is the most common primary brain tumor with a poor prognosis despite advances in various treatment modalities, such as radiation therapy (RT). This study compared the tumor growth inhibition effects of focused ultrasound-targeted microbubble destruction (UTMD) therapy with the RT using an orthotopic mouse glioma model. Mice were implanted with GL261 glioblastoma cells and divided into three groups: control group (no treatment); RT group (2 Gy/day, 5 days/week, 3 consecutive weeks); and UTMD group (FUS sonication in the presence of systemically injected microbubbles at the peak negative pressure of 1.5 MPa, frequency of 1.44 MHz, and 2 treatments/week for 3 consecutive weeks). Contrast-enhanced magnetic resonance imaging (MRI) was performed once every four days for measuring the tumor volume. Both UTMD and RT caused significant growth inhibition compared to the control group; however, there was no significant difference between the UTMD and RT groups. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining showed that the number of apoptotic tumor cells in both RT and UTMD groups were significantly higher than the control group without the difference between these two groups. This study suggests that UTMD suppressed glioblastoma tumor growth and this effect was comparable with that achieved by RT.
National occupational research agenda for hearing loss prevention
Authors: Murphy William J. , Azman Amanda S.
Published: April 2019

The National Institute for Occupational Safety and Health (NIOSH) has a mandate to conduct research on occupational safety and health. The research portfolio is organized by industrial sectors and cross-sectors for illnesses and injuries that are found in all sectors. The Hearing Loss Prevention research cross sector council comprises representatives from government, labor organizations, academia, and industry representatives. The HLP council held several meetings throughout 2018 to determine research needs for occupational hearing loss prevention in the United States. Five topic areas were determined. (1) Provide input for policies and guidelines that will inform best practices for hearing loss-prevention efforts. (2) Develop effective, evidence-based education designed to improve hearing conservation program outcomes for exposed workers and management. (3) Develop, commercialize, and widely implement noise control solutions on jobsites in key industries. (4) Develop audiological tests for hearing loss prevention. (5) Improve occupational hearing loss surveillance. These topic areas will be discussed in detail to help motivate other researchers to join further our knowledge to prevent occupational hearing loss.
Variation of sound events that stand out in one's memory across the ages: Comparison between 2008 and 2016
Authors: Akita Takeshi , Qu Lei
Published: April 2019

To contribute to create good soundscape, sound events that stand out in one's memory are surveyed. In the present research, the data of written questionnaire that is carried out in the coursework of acoustics is analyzed. Especially, results of 2016 are compared with that of 2008. In the questionnaire, students are instructed to write down sound events that are easily recalled at the moment, after they remember the sound events that they heard in the period from the time of awakening to the coursework. Additionally, students evaluate each sound event whether they have good or bad impression. As the result, average of recalled sound events was 10.1 per person in 2016 while it was 8.2 in 2008. Sound events are classified into three large categories at each year, and the composition of the classification is the same between 2016 and 2008. They are labeled as "Sound produced by a person or people", "Artificially produced sound", and "Nature sound." In 2016 data, the number of artificially produced sound that has no good nor bad evaluation increases significantly in comparison to 2008. It is suggested that popularization of information technology and smartphone produces more electronic sound in the urban soundscape.
Improved infrasound array processing with robust estimators
Authors: Bishop Jordan W. , Fee David , Szuberla Curt
Published: April 2019

Accurate infrasound source and path characterization rely on high-quality array processing parameter estimates. Physical and statistical assumptions underlying conventional array processing techniques sometimes fail in practice due to propagation effects or station degradation. Unlike conventional least squares regression, robust regression estimators are relatively insensitive to data that deviate from the assumed planar model. We compare two such estimators, M-estimators, and least-trimmed squares (LTS), to conventional array processing methods (frequency-wavenumber beamforming, progressive multi-channel cross correlation, L1 regression, and ordinary least squares) using synthetic and real infrasound data. Synthetic testing suggests that robust estimators are resistant to timing errors and noise contamination. We also present case studies from both International Monitoring System and the Alaska Volcano Observatory infrasound data that demonstrate how these techniques have produced accurate array processing results despite an element polarity reversal, timing error due to the loss of GPS lock, and a deviation from the plane wave assumption. We also evaluate the effectiveness of these techniques to arrays with differing geometries and number of elements, and note that the examination of LTS residuals enables outlying inter-element differential times to be flagged automatically, providing a data quality tool.
Probabilistic inversion for submerged or buried source depth and strength from infrasound observations
Authors: Averbuch Gil , Waxler Roger M. , Evers Läslo G.
Published: April 2019

In seismology, the depth of a near surface source is hard to estimate in the absence of local stations. However, long-range infrasound propagation from an underwater or underground source is very sensitive to variations in its depth. This characteristic is employed in an infrasound based inversion for the sources depth and effective-acoustic-strength (EAS). A synthetic dataset, generated by the Fast-Field-Program (FFP), is used to investigate the accuracy of a Bayesian inversion scheme under the variations of the number of stations, source depth, and signal-to-noise ratio (SNR). SNR has proved to have the most dominant influence on the inversion precision. Results from a single station inversions with SNR = 5 had a standard deviation (SD) of ±20m in depth and 10% in EAS. For SNR = 1, SD values increased to ±40 m in depth and 40% in EAS. Similar results were obtained from five and ten stations inversions. This is the first attempt to extract the absolute source depth and EAS from long-range infrasound signals. Results show that infrasound may be used to accurately obtain underwater and underground source parameters.
Listening while balancing: Dual-task costs in speech vs. noise maskers
Authors: Helfer Karen S. , Freyman Richard L. , Van Emmerik Richard , Banks Jacob , Clauss Michael , Dunn Lincoln
Published: April 2019

Many middle-aged adults report that listening is effortful in adverse communication situations. One means of quantifying listening effort is by measuring dual-task costs. The present study examined the influence of early aging on dual-task costs using a technique which required participants (younger and middle-aged adults) to complete a postural control task while listening to speech. For the postural control task, participants stood on a force platform and had to maintain their center of pressure within a prescribed area (denoted using real-time visual feedback). Two speech perception tasks were used, each presented with two types of maskers (same-sex two-talker speech masker and steady-state speech-shaped noise): repeating back low-predictability sentences, and listening to Connected Speech Test passages and then answering content questions based on each passage. This presentation will describe data analyses designed to uncover how listener age group and masker type influenced listening effort as measured by dual-task costs. [Work supported by NIDCD 012057.]
Is auditory distance perception in rooms binaural?
Authors: Prud'homme Luna , Lavandier Mathieu
Published: April 2019

The goal of this study was to determine whether auditory distance perception is binaural or monaural. Listeners performed an experiment in which they judged the distance of a sound source using headphones. Individualized and non-individualized binaural room impulse responses were measured to simulate sound sources placed between 1 and 4 m in front of the listener. The listening test was performed in the same room used for the measurements, and listeners were facing visual anchors. Different conditions tested the influence of controlling the sound level, individualizing the stimuli, and the amount of binaural information present in these stimuli. Results showed that binaural information does not seem to be necessary for auditory distance perception in rooms for naive listeners. However, its absence can alter externalization of sounds, which could prevent listeners from judging distance via headphones when it creates a mismatch between auditory and visual information. The variation of the sound level was a preponderant cue used by the listeners. Its absence or artificial variation greatly altered distance judgments for naive listeners.
A method for conversational signal-to-noise ratio estimation in real-world sound scenarios
Authors: Mansour Naim , Marschall Márton , May Tobias , Westermann Adam , Dau Torsten
Published: April 2019

The analysis of conversational signal-to-noise ratios (SNRs) measured in real-world scenarios can provide vital insight into people's communicative strategies and difficulties and guide development of hearing devices. However, measuring SNRs accurately and realistically is challenging in typical recording conditions, where only a mixture of sound sources is captured. This study introduces a novel method for realistic in situ SNR estimation, where the speech signal of a person in natural conversation is captured by a cheek-mounted microphone, adjusted for free-field conditions, and convolved with a measured impulse response to estimate the clean speech component at the receiver. A microphone near the receiver computes the noise-only component by applying a voice activity detector. Obtained SNR values are analyzed using in situ recordings of a real-world workspace meeting. It is shown that the temporal resolution is increased, and fluctuations in the speech level are more accurately tracked compared to a typical spectral-subtraction-derived method. The application of the proposed SNR estimation method may be valuable for compensation procedures in hearing instruments that take conversational dynamics into account.
Sound source localization in two-dimensions: Rotating sources and listeners
Authors: Yost William , Pastore M. Torben
Published: April 2019

In 1940, Wallach published the last of three articles on localizing sound sources in two dimensions: azimuth and elevation. He proposed: “Two sets of sensory data enter into the perceptual process of localization (1) the changing binaural cues and (2) the data representing the changing position of the head.” Wallach explained how head motion resolves cone-of-confusion errors to support his proposal. A group of experiments in which listeners and sound sources rotated on the azimuth plane demonstrated how head motion contributes to localization in terms of both azimuth and elevation by inducing illusory perceived sound source locations. The results generally supported his proposal regarding head motion. As Wallach was not aware of aspects of current knowledge of sound source localization, such as the role of head-related-transfer function, HRTF, and the use of the resulting spectral cues, some of his conclusions turn out to be incorrect. We conducted a series of experiments similar to Wallach's to more fully examine the roles of head and sound source rotation in localizing sound sources in two-dimensional auditory space. Some of these results will be described in this presentation. [Work supported by NIDCD and Facebook Reality Labs.]
Integration of auditory and tactile stimuli in the perception of building noise and vibration
Authors: Loshin Ben , Braasch Jonas
Published: April 2019

Auralization is used in architectural and environmental planning to build a visceral understanding of a design. However, current auralization techniques are limited to the auditory sensory modality, while real environments require the integration of complex stimuli across multiple modalities. This study explores the human perception of coupled sound and vibration sources encountered in real spaces through the creation of immersive virtual representations of those spaces. Acoustic and vibration responses are combined with common building noises and simulated on a calibrated motion platform, incorporating vertical whole-body vibration with binaural audio. Test participants are asked to make judgments of relative loudness and annoyance of building sounds simulated in combination with different vibrational contents. Test results are compared with those published in other studies on the psychophysics of audio-tactile summation, and the implications of the results are discussed with respect to the perception of building noise.
Binaural modeling from an evolving habitat perspective
Authors: Braasch Jonas
Published: April 2019

Functional binaural models have been used since the mid-20th century to simulate laboratory experiments. The goal of this chapter is to extend the capabilities of a cross-correlation model so it can demonstrate human listening in complex scenarios found in nature and human-built environments. A ray-tracing model is introduced that simulates a number of environments for this study. This chapter discusses how the auditory system is used to read and understand the environment and how tasks that require binaural hearing may have evolved over the course of human history. As use cases, sound localization in a forest is examined, as well as the binaural analysis of spatially diffuse and rectangular rooms. The model is also used to simulate binaural hearing during a walk through a simulated office-suite environment. [Work supported by NSF BCS-1539276 and CISL.]
Relationship between localization acuity and spatial release from masking
Authors: Srinivasan Nirmal Kumar , Wince Jess
Published: April 2019

Spatial Release from Masking (SRM) is defined as the ability to obtain better Speech Recognition Thresholds (SRTs) when the masking sounds are spatially separated from the target sound. Localization refers our ability identify the direction of the sound and localization acuity is measured as the difference in locations between the actual and perceived locations. SRM and localization share many common cues on how the task is performed. Here, we present data from young normal hearing on SRM task using Coordinate Response Measure (CRM) sentences and localization acuity using three different noise Gaussian white noise bursts: low pass (1/3 octave wide centered at 500 Hz), high pass (1/3 octave wide centered at 3150 Hz), and broadband (200–5000 Hz). Thirteen loudspeakers (Orb Mod 1), separated by 15 deg in the frontal plane were used to present the stimuli. Initial analyses of the results indicated that, as expected, all the listeners obtained substantial spatial release from masking consistent with the literature, filtering the broadband noise had little effect on localization acuity for listeners with normal hearing. Finally, the relationship between SRM and localization acuity will be discussed.
Benefits from different types of acoustic beamforming in bilateral cochlear-implant listeners
Authors: Yun David , Jennings Todd R. , Mason Christine , Kidd Gerald , Goupell Matthew
Published: April 2019

Acoustic beamforming improves speech reception in "noise" at the cost of removing spatial cues. Recently, novel approaches have been proposed for enhancing speech reception via beamforming while preserving sound localization by reintroducing natural binaural cues to the beamformer output. It is, however, unclear whether such a hybrid approach will improve performance for bilateral cochlear-implant (BICI) listeners because they receive little benefit from natural spatial cues. Here, effects of beamforming on masked speech reception thresholds (SRTs) were determined in BICI and normal-hearing (NH) listeners for a standard single-channel beamformer and a new triple-beamformer comprising a diotic central beam, -40 deg left-ear-only beam, and + 40 deg right-ear-only beam [Jennings and Kidd, JASA 143, 1743]. Speech targets and maskers were co-located (0 deg) or maskers were symmetrically separated at ±30 deg or ±90 deg. Natural binaural listening, single-channel beamformer, and triple-beamformer conditions were tested. Both beamformers were better than natural cues. For BICI listeners, single-channel beamforming improved SRTs by 5 (±30 deg) and 15 dB (±90 deg). SRTs for the triple-beam were best for NH but were 5 dB worse than the single-channel beam for BICI listeners. These preliminary findings suggest beamforming provides significant spatial release from masking for BICI listeners but assessing overall benefit, including localization, awaits further study.
Effects of auditory-nerve loss on tone detection in roving-level noise
Authors: Henry Kenneth S. , Amburgey Kassidy N. , Abrams Kristina S.
Published: April 2019

Auditory-nerve (AN) loss has emerged as a significant public health concern because it occurs steadily with age and potentially following noise-induced temporary threshold shifts. AN loss without hair-cell damage remains undetectable with an audiogram yet is commonly assumed to degrade auditory perception under real-world, noisy conditions. Here, we tested whether AN loss impacts behavioral tone-in-noise (TIN) detection in the budgerigar, an avian species with sensitivity similar to humans on many simple and complex listening tasks. AN damage was induced with kainic acid and confirmed using auditory evoked potentials and otoacoustic emissions. TIN thresholds were quantified in 1/3-octave noise as a function of frequency and sound level using operant conditioning and two-down, one-up, adaptive tracking procedures. Kainic acid reduced gross AN potentials by 40%–70% across animals without impacting otoacoustic emissions. TIN thresholds in control animals decreased with increasing frequency and showed minimal elevation (<1 dB) when sound level was roved ±10 dB across trials. TIN thresholds in kainic-acid exposed animals were as sensitive as in the control group and showed similar preservation with roving sound level. These results suggest a minimal impact of AN loss on behavioral TIN detection, even under conditions requiring rapid adaptation to changing sound level.
Suspension optimization for a compressor assembled on a refrigerator
Authors: Pescador Sarda Alexandre A. , Lenzi Arcanjo
Published: April 2019

Noise annoyance generated by electrical machines is evaluated based on the sound power level (SPL) parameter measured in a reverberationroom or using a semi-anechoic chamber. However, when the machine is assembled in a base plate, the SPL can be altered depending on the new system configuration and the way the machine is assembled in the final product. The vibration generated in the electrical machine is transmitted to the base resulting in noise at the surface. The aim of this study was to model the suspension of a general machine assembled in a flexible base and minimize the vibratory power flow transmitted to the base through an optimization process, taking into account parameters such as the spring inclination, stiffness, and suspension damping. Decreasing the power flow to the base results in a reduction in the global levels of noise and vibration at the base plate.
Extending bandwidth for sound power measurements
Authors: Mortenson Michael C. , Gilbert Suzanna , Neilsen Tracianne B. , Gee Kent L. , Sommerfeldt Scott D.
Published: April 2019

Sound power is often measured using the intensity-based engineering standard ANSI S12.12-1992. Traditional methods for intensity-based sound power estimation are limited in bandwidth at low frequencies by phase mismatch between microphones and at high frequencies by microphone spacing—with errors occurring well below the spatial Nyquist frequency. The PAGE (Phase and Amplitude Gradient Estimation) method has been used to extend the bandwidth of intensity calculations [Gee et al., J. Acoust. Soc. Am. 141(4), EL357–EL362 (2017)]. This paper examines the efficacy of the PAGE method to overcome bandwidth limitations in estimating sound power. Specifically, the sound fields from three sources—a blender, a vacuum cleaner, and a dodecahedron speaker—were measured according to ANSI S12.12-1992. The sound power was computed for each source using both the traditional and PAGE methods. The resulting intensity-based sound power estimates are compared against sound power measurements obtained according to the scientific-grade ISO 3741:1999 standard. The PAGE method increases the bandwidth over which reliable estimates are achievable for intensity-based sound power estimates, even exceeding the spatial Nyquist frequency when phase unwrapping is successful. Thus, using existing equipment, industry professionals can extend the bandwidth of sound power estimates with the PAGE method. [Work supported by NSF.]
Uncertainty quantification for right-sizing computational models of sound propagation in the atmospheric boundary layer
Authors: Pettit Chris L. , Wilson D. K. , Hart Carl R.
Published: April 2019

Comprehensive modeling of sound propagation through the atmospheric boundary layer is viewed as a judicious combination of accurate computational mechanics models and uncertainty quantification (UQ) methods. The role of numerical models is to represent nominally deterministic phenomena, e.g., geometrical spreading, ground interactions, refraction by mean gradients of wind and temperature. The role of UQ is to characterize the consequences of fundamentally non-deterministic and imprecisely known factors that affect propagation, e.g., turbulence in the atmospheric boundary layer, complex terrain features, and overly sparse spatio-temporal sampling of propagation parameters. High-fidelity wave propagation mechanics cannot compensate for inherent randomness in the environment and insufficient data on the parameters. When uncertainty is significant, the computational cost of high-fidelity models might be better invested in more ensemble simulations with medium-fidelity models and quantifying the payoff from more data about the environment. Work in recent years along three thrusts to enable this form of comprehensive modeling is reviewed: (1) Surrogate modeling based on cluster-weighted models, which are a type of probabilistic generative model, and on statistical learning methods, (2) global sensitivity analysis for assessing the importance of model parameters, and (3) a computational mechanics error budget for rationally analyzing the importance of various sources of uncertainty.
Methods for including uncertainty in modeling and simulation of acoustic propagation in ocean waveguides
Authors: Finette Steven I.
Published: April 2019

Two main classes of uncertainty are associated with modeling and simulation of acoustic fields in ocean waveguides. These classes, generally known as aleatory and epistemic uncertainties, represent opposite ends of a spectrum of possible types of imperfect knowledge concerning the system. Aleatory uncertainty can be interpreted physically as natural ocean variability which is typically characterized by probability density functions, provided sufficient information is available to justify their specification. On the other hand, epistemic uncertainty is associated with incomplete scientific knowledge concerning some aspect(s) of the system under analysis. While epistemic uncertainty can be reduced by the inclusion of additional information, e.g., data refinements, acquisition of additional data or more realistic modeling of the system, aleatory uncertainty cannot be eliminated or reduced because it is judged by the modeler to be inherent in the structure of the system. Both types of uncertainty are discussed, with an emphasis on the aleatory contribution based on stochastic basis expansions. Tradeoffs with Monte-Carlo and Bayesian methods are also considered. When density functions are not available, weaker inferential estimates based on epistemic approaches are appropriate and a hybrid aleatory-epistemic framework is outlined for treating these situations. [Work supported by the Office of Naval Research.]
Bayesian calibration of underwater propagation models under uncertainty
Authors: Muehleisen Ralph T. , Swift S H. , Li Qi
Published: April 2019

Propagation models are notorious for the uncertainty of important parameters such as source strength, speed of sound profiles, and reflecting surface profiles. In many cases, one calibrates a model to measured data (e.g., sound levels or transmission loss) for the purposes of estimating these model parameters, i.e., for inverse modeling. Bayesian calibration methods have been developed that are extremely useful for calibration of models where parameters have high levels of uncertainty and problems may be under or over determined. The Kennedy and O’Hagen framework which uses a Gaussian process surrogate model to replace the model under calibration is especially useful when the underlying model is computationally expensive, and so, it may be difficult to apply many optimization based calibration methods. In this talk, we describe the application of the Kennedy and O’Hagen Bayesian Calibration framework to the calibration of an underwater ray tracing propagation model. The source strength and parameters for the sound speed profile are considered as highly uncertain. The Bayesian calibration technique is shown to improve model prediction and reduce the uncertainty of the unknown propagation parameters.
Three-dimensional underwater sound pressure sensitivity in oceanic environments
Authors: Lin Ying-Tsong
Published: April 2019

Physical oceanographic processes, marine geological features, sub-bottom geoacoustic structure, sea surface disturbances, etc., can either individually or jointly affect underwater sound propagation in the ocean and cause significant temporal and spatial variability in the sound pressure field. The primary goal of this study is to develop a numerical scheme to determine the sound pressure sensitivity in response to variations of index of refraction due to changes of environmental conditions. This sensitivity analysis is an exention of the Born approximation which assumes perturbations at infinitesimal points. To handle disturbance within a finite volume, an improved sensitivity kernel is derived from a higher-order parabolic-equation (PE) approximation. With this sensitivity kernel, we can analyze the spatial distribution and the temporal evolution of the acoustic sensitivity field in complex oceanic environments. This paper will present numerical examples of three-dimensional (3D) sound propagation in continental slopes, submarine canyons, and nonlinear internal wave fields. Discussions on other applications, including uncertainty quantification of transmission loss prediction and adjoint models for 3D acoustic inversions, will also be provided. [Work supported by the Office of Naval Research.]
Model-data comparison of sound propagation in a glacierized fjord with a variable ice top-boundary layer
Authors: Zeh Matthew C. , Glowacki Oskar , Deane Grant B. , Ballard Megan S. , Pettit Erin C. , Wilson Preston S.
Published: April 2019

Transmission loss measurements were conducted in the meltwater-modified surface layer near Hansbreen Glacier in Hornsund Fjord in southwestern Svalbard in September 2017 [Deane and Glowacki, JASA 143, 1711 (2018)]. An m-sequence source signal (149 dB re 1 μPa, 11 kHz carrier frequency) was tethered at 7 m depth to a boat drifting from 0 to 200 m. This signal was received by two Hitech HTI-96 hydrophones at 8 and 17 m depth deployed from a stationary boat anchored 500 m from the glacier. Within this environment, and typical for a glacierized fjord, regular calving events contributed to an ice mélange top boundary layer with larger icebergs occasionally obstructing the signal transmission path. The propagation environment was upward refracting, causing propagation sound to repeatedly reflect from the surface layer. A ray-based approach was applied to model the measured data. The variability of the top boundary was included in the model by incorporating surface scattering and inserting icebergs. Comparisons between several increasingly complex iterations of this model with the collected data will be presented. [Work supported by the NDSEG Fellowship, ONR Grant Nos. N00014-17-1-2633 and N00014-14-1-0213, and the Polish National Science Centre Grant No. 2013/11/N/ST10/01729.]
Individualization of head-related transfer functions using sparse representation approach
Authors: Xiangyang Zeng , Lei Wang , Dongdong Lu , Cai Huaizhen
Published: April 2019

The individualization of Head-Related Transfer Functions (HRTFs) is an important issue for enhancing the performance of binaural auralization. In this paper, the HRTFs and anthropometric parameters of Chinese people were measured and analyzed. A sparse representation approach was suggested to synthesize individualized HRTFs with selected anthropometric features. The approach was compared with two other methods proposed in previous studies by comparing the spectrum distortion of each method for objective evaluation. Then, subjective experiments were conducted to investigate the performance of the optimized HRTFs in binaural localization. The evaluation results show that the proposed HRTFs individualization approach has smaller spectrum distortion and better localization performance than that of the reference methods.
Diffusion equation modeling in sound field analysis of disproportionate rooms and coupled spaces
Authors: Sü Gül Zühre
Published: April 2019

This study discusses alternative models and methods to be applied in room acoustics estimations for specific room types including disproportionate rooms and rooms with coupled volumes. A recent prediction method, namely, diffusion equation model (DEM) in room acoustic applications is utilized in the methodology, and this method is compared to common models as of statistical theory, image-source or ray-tracing techniques. Both long enclosures as of subway stations and coupled volumes as of multi-domain monumental structures are special cases with specific interior sound fields. Statistical theory is not always reliable in such extraordinary room forms, while ray tracing may tend to over or under estimate certain acoustical parameters. Thus, the application of DEM in a finite element scheme for detailed sound energy decay and sound flow analysis are held over some case structures. The results are compared to field tested data and ray-tracing solutions. Pros and cons of DEM in comparison to different methods are searched in detail considering the efficiency in visualization, computational speed, and reliability of acoustical parameter results for specific room shapes.
Gas stabilizing titanium dioxide nanocones against desmoplastic cancer by ultrasound cavitation induced tumor penetration and sonodynamic therapy
Authors: Thomas Reju G. , Kwan James J.
Published: April 2019

Sonodynamic therapy is an emerging technique for treating tumors by utilising ultrasound mediated reactive oxygen species (ROS) production from sonodynamic agents. Here, we have manufactured titanium dioxide nanocones (TDN) for local on-demand ROS generation. These nanocones nucleate inertial cavitation during exposure to therapeutic ultrasound. Furthermore, inertial cavitation enhances the penetration of the TDN into tissue. The particles were synthesized by a hydrothermal method in the presence of 1,6-hexanediamine as stabiliser. Electron microscopy images confirm the formation of nanocone structures with a size of 300 nm (and confirmed with dynamic light scattering). The TDN displayed an inertial cavitation threshold of 1.9 MPa for a 0.5 MHz ultrasound transducer at 5 mg/ml concentration. We also show that FITC conjugated TDN penetrated 2% agarose mold upto 1.2 cm distance after exposure to ultrasound for 10 min. Finally, a ROS release profile of TDN under ultrasound exposure was established using ROS sensor 1,3-diphenylisobenzofuran (DPBF). After 15 min of exposure to high intensity focused ultrasound (0.5 MHz center frequency) time, TDN in the presence of DPBF showed a significant decrease in UV absorbance compared to control, verifying that ROS were generated under ultrasound exposure. TDN opens up the potential for targeted sonodynamic cancer therapy.
Microbubble translation in plane-wave ultrasound transmission
Authors: Supponen Outi , Guidi Francesco , Upadhyay Awaneesh , Vos Hendrik J. , Borden Mark , Tortoli Piero
Published: April 2019

Primary radiation force is capable of translating microbubbles in the focal region of single-element and array ultrasound probes. This effect can be harnessed to enhance the contact between ligand-bearing microbubbles and targeted endothelium for applications in targeted drug delivery and ultrasound molecular imaging. In this study, displacements of lipid-coated microbubbles associated with plane-wave transmission are investigated using the multi-gate Doppler approach, and compared with focused-wave transmission at equivalent peak negative pressures. In plane wave transmission, the radiation force is nearly uniform over the field of view and therefore allows for a more uniform translation of microbubbles compared to focused wave. Statistically determined median displacements are in good agreement with the axial and lateral ultrasound beamplots both in plane-wave and focused-wave transmissions, while peak microbubble displacements reveal a number of discrepancies. Distinct size-isolated microbubble populations (diameters 1–2 μm, 3–4 μm, 4–5 μm, 5–8 μm, and polydisperse) were tested, showing important differences in their displacements and a strong driving frequency dependence thereof. These findings help tune the ultrasound transmission parameters for uniform and size-selective microbubble translations.
Deep learning for underwater noise classification
Authors: Chen Johnny L. , Nguyen Sarah , Trader Jason M. , Moore Andrew , Summers Jason E.
Published: April 2019

Deep-learning models have surpassed many computer-vision benchmarks and groups such as Google have begun to investigate similar methods for understanding underwater data. Understanding underwater soundscapes is critical to many applications such as assessing the impacts of anthropogenic noise on sea life and monitoring the health and biodiversity of the ocean. In this work, we present a computer-vision approach for classifying audio signals to distinguish whale sounds—especially, vocalizations from mysticetes—from other sources of sound in the underwater soundscape, such as ships. This is a challenging problem due to wide variation in ambient background noise, sensor configuration and properties, and whale vocalization patterns within and across species. Here, we adapt deep convolutional neural networks (CNN) to analyze spectral patterns of common noise sources and demonstrate robust performance on a dataset of ambient noise derived from multiple open-source databases including whale vocalizations from eight species and shipping noise from over ten platforms observed across multiple environments with a variety of sensors. Performance of the network is characterized in terms of classification accuracy and generalizability as a function of CNN hyperparameters and training architecture. With a CNN trained from scratch, we analyze the learned features of the classification decisions of the network by adapting several visualization techniques from the computer-vision domain.
How fast will the Antarctic ice sheet retreat?
Authors: Steig Eric J.
Published: April 2019

Feedbacks between glacier retreat and the solid Earth may slow ice loss from Antarctica
Molecular Bacterial Load Assay Concurs with Culture on NaOH-Induced Loss of Mycobacterium tuberculosis Viability
Authors: Mtafya Bariki , Sabiiti Wilber , Sabi Issa , John Joseph , Sichone Emanuel , Ntinginya Nyanda E. , Gillespie Stephen H.
Published: April 2019

Effective methods to detect viable
Mycobacterium tuberculosis
, the main causative agent of tuberculosis (TB), are urgently needed. To date, cultivation of
M. tuberculosis
is the gold standard, which depends on initial sample processing with
N
-acetyl-
l
-cysteine–sodium hydroxide (NALC-NaOH), chemicals that compromise
M. tuberculosis
viability and, consequently, the performance of downstream tests.
Regularities and mechanism of heavy metal cations sorption and (or) proton desorption by chitosan from aqueous solutions
Authors: Nikiforova T.E. , Kozlov V.A. , Islyaikin M.K.
Published: April 2019

The sorption process of heavy metal ions from aqueous solutions using chitosan flakes and chitosan beads was studied. Chitosan gel beads were prepared using covalent crosslinking of chitosan chains by epichlorohydrin with ionic gelation by sodium tripolyphosphate. The capability of chitosan beads to absorb the heavy metal ions from aqueous solutions was studied, and the physicochemical characteristics of the sorbent were evaluated using SEM and FTIR on the model solution treatment. It was found that competitive proton sorption takes place in acidic media, which results in a transformation of amino groups into inactive ammonium-salt form and decreases in heavy metal sorption onto chitosan from aqueous acidic media. Batch adsorption experiments were performed to examine the influence of various factors such as the initial concentration of metal salts, pH, and agitation duration on the process. It was established that metal ion sorption is pH dependent and has an optimum effect at a pH of 6.0. Following the Langmuir equation, the maximum sorption of Cu2+ions is estimated to be 1,6 mol/kg of modified chitosan. The kinetic study revealed that the adsorption kinetics are well-fitted to the kinetic equation of pseudo second order. Thus, sorption of heavy metal ions by chitosan is considered to be a competitive process that occurs on amino groups of the sorbent with equivalent coordinated participation of metal cations, protons, and anions.
Influence of nanoparticle dispersibility on hygrothermal properties of HNT-GFRP/BFRP nanocomposites
Authors: Park Soojeong , Choi Jisu , Lee Jinwoo , Yu Tianyu , Chen Zixuan , Kim Yunhae , Bae Changwon
Published: April 2019

In the nanocomposite, the dispersion and bonding properties of the nanoparticles at the interfaces were major factors that were related to the physical properties of the final product. Nanoparticle aggregation mainly occurs in the dispersion process between nanoparticles and a polymer. In addition, re-aggregation phenomenon generates by large amounts of pores during curing process. In this case, it was necessary to break the physical bonds, such as the attraction between the initial nanoparticles, and achieve a smooth chemical bonding with the polymer. In this study, the effect of halloysite nanotube (HNT) dispersion on the interfacial bonding was compared and analyzed in [Formula: see text] high temperature water environment over 30 days by adding 0.5 wt.% HNT to glass fiber reinforced plastic (GFRP) and basalt fiber reinforced plastic (BFRP). As a result, the HNT contributed to disturbing the moisture absorption rate. It has great effect on thinner lamination part. Moreover, the thicker the lamination, the less the HNT re-aggregation occurred on the curing process. This phenomenon showed a uniform dispersion in the entire laminate area. The weight recovery rate by moisture absorption was high in the HNT-glass fiber (GF), because structural relationship between HNT and GF are larger than in epoxy resin.
Linear-State Differential Games in Partition Function Form
Authors: Hoof Simon
Published: April 2019

We introduce a partition function for [Formula: see text]-player linear-state cooperative differential games. The value of a coalition within a given coalition structure is defined as its noncooperative equilibrium payoff of a game played between the coalitions. We also define two core notions, namely, the cautious and the singleton core. If the game is convex, then the cores are nonempty. In order to illustrate the approach, we consider a symmetric game of pollution accumulation.
Mechanical Property and Damage Evolution of Polymer-Bonded eXplosive Substitute Under Biaxial Compression
Authors: Xu Panpan , Xie Shejuan , Chen Hong-En , Chen Zhenmao , Chen Hua , Zhang Weibin , Liu Bende , Dai Bin , Zhou Haiqiang , Li Jingming , Li Peng
Published: April 2019

Understanding both the mechanical property and the crack propagation behavior of Polymer-bonded eXplosive (PBX) material under biaxial compression is critical to predicting its safe working life. In this study, a number of PBX substitute specimens were tested under lateral confining pressures varying from 0 to 40[Formula: see text]MPa to better understand the mechanical behavior and damage evolution characteristics of PBX material under biaxial compression. The failure modes, ultimate strength and deformational behavior of PBX substitute under biaxial compression were observed using digital image correlation (DIC) method, and the damage of material was evaluated through the quantitative analysis of micro-computed tomography (CT) images of post-test specimens. The results indicate that the confining stress in the biaxial minor principal direction has a noticeable effect on the strength and deformational behavior of the PBX substitute material and the maximum increase of compressive strength occurs at a lateral confining pressure around 30[Formula: see text]MPa. The three-dimensional morphology of cracks was also examined quantitatively. The extent and complexity of crack damage were found increasing with the lateral confining pressure when it is smaller than 30[Formula: see text]MPa.
Parametric Resonance Characteristics of Woven Fiber Metal Laminated Plates
Authors: Prasad Elluri Venkata , Sahu Shishir Kumar
Published: April 2019

The present investigation deals with the assessment of parametric resonance behavior of new aircraft material, i.e., woven fiber metal laminated (FML) plates subjected to in-plane static and harmonic loading using finite element (FE) technique and Bolotin’s method. In this analysis, a four-node isoparametric element with five degrees of freedom per node is adopted. Based on the first-order Reissner–Mindlin theory, the parametric instability of FML plate subjected to in-plane harmonic loading is examined. A MATLAB code is developed for the parametric study on the dynamic stability of FML plates. The reliability of present formulation is checked by comparing numerical results obtained from present FE analysis with the published researches in the field. The influences of several factors, viz. static load factor, aspect ratio, length-to-thickness ratio, number of layers, ply orientation and boundary conditions on the dynamic instability regions are discussed. Significant variations of these factors on dynamic instability zones of FML plates are observed. The instability zones can be used as guidelines for the prediction of the dynamic behavior of FML plates.
Mechanical Damage of YBa2CU3O7-Coated Conducting Film Caused by Its CeO2 Interface with Defects
Authors: Wang Tiange , Li Zhixin , Cao Jinjin , Gou Xiaofan
Published: April 2019

YBa2Cu3O7 (YBCO) multilayer coating conductors are the second generation superconductor wires. The interface structure plays an important role in the performance of the material, especially that between the superconducting layer and the CeO2 buffer layer. The YBCO/CeO2 interface is not only very critical on the atomic scale for effectively modulating the polycrystalline structure of YBCO, but also, as weak connection on the macro level, profoundly affect macro physical properties of the whole film, for example, mechanical toughness. Generally, most defects at the YBCO/CeO2 interface are generated during the fabrication, and further develop when the film is wound or in the process of current carrying. These defects, at different level, lead to mechanical damage even under simple deformations such as tension and bending. In this work, by way of atomistic computer simulations with the molecular dynamics (MD), a two-dimensional YBCO/CeO2 interface atomic model was developed and validated. On this interface model, the damage propagation on the atomic-scale and further analysis with stress and potential energy especially affected by the YBCO/CeO2 interface with/without defects under the tension and bending have been comprehensively investigated. As a result, we not only visualized the simulated damage process and route on the YBCO/CeO2 interface, but also more importantly, combined with the variation of macro properties, deeply analyzed the damage mechanism caused by the interface and its defects.