bluuebunny/crossref_metadata_2025 huggingface dataset:
Torsional Vibrations and Nonlinear Dynamic Characteristics of Drill Strings and Stick-Slip Reduction Mechanism
Authors: Tian Jialin , Li Genyin , Dai Liming , Yang Lin , He Hongzhi , Hu Shuhui
Published: April 2019

Torsional stick–slip vibrations easily occur when the drill bit encounters a hard or a hard-soft staggered formation during drilling process. Moreover, serious stick–slip vibrations of the drill string is the main factor leading to low drilling efficiency or even causing the downhole tools failure. Therefore, establishing the stick–slip theoretical model, which is more consistent with the actual field conditions, is the key point for new drilling technology. Based on this, a new torsional vibration tool is proposed in this paper, then the multidegree-of-freedom torsional vibrations model and nonlinear dynamic model of the drill string are established. Combined with the actual working conditions in the drilling process, the stick–slip reduction mechanism of the drill string is studied. The research results show that the higher rotational speed of the top drive, smaller viscous damping of the drill bit, and smaller WOB (weight on bit) will prevent the stick–slip vibration to happen. Moreover, the new torsional vibration tool has excellent stick–slip reduction effect. The research results and the model established in this paper can provide important references for reducing the stick–slip vibrations of the drill string and improving the rock-breaking efficiency.
Kinematic Design of a Novel Two Degree-of-Freedom Parallel Mechanism for Minimally Invasive Surgery
Authors: Cao Wen-ao , Xu Shi-jie , Rao Kun , Ding Tengfei
Published: April 2019

A novel two degree-of-freedom (2-DOF) parallel mechanism with remote center-of-motion (RCM) is proposed for minimally invasive surgical applications in this paper. A surgical manipulator with expected three-rotation and one-translation (3R1T) outputs can be obtained by serially connecting a revolute pair (R) and a prismatic pair (P) to the mechanism. First, kinematics of the new mechanism is analyzed and the corresponding velocity Jacobin matrix is established. Then, singularity identification of the mechanism is performed based on screw theory. Further, main dimensions of the mechanism are designed, and a physical prototype is developed to verify the effectiveness of executing RCM. The proposed mechanism has relatively simple kinematics, and can obtain a noninterference and nonsingularity cone workspace with the top angle of 60 deg based on a compact structure.
The performance of Tetranychus urticae on five melon cultivars is correlated with leaf thickness
Authors: Xu Dandan , Wang Ke , Zhang Yating , Wang Huaisong , Wu Qingjun , Wang Shaoli
Published: April 2019

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an important pest of melons. In this laboratory study, we used two-sex life table to evaluate the performance of T. urticae on five melon cultivars (IVF28, IVF118, IVF168, IVF437, and Yangjiaomi). We also evaluated the correlation between mite population growth and morphological characteristics of leaves. The results showed that the total immature time, adult longevity, total longevity, and fecundity of the spider mite differed among the cultivars. On IVF28, the values for the intrinsic rate of increase (r) and the finite rate of increase (λ) were 0.1638 d-1 and 1.1178 d-1, respectively, which were significantly lower than the values on IVF168, IVF118, or Yangjiaomi. Values for r and λ tended to be highest on IVF168. In addition, r values for T. urticae were not correlated with trichome density or stomatal density but were negatively correlated with melon leaf thickness. In summary, the different melon cultivars exhibited distinct levels of resistance to T. urticae and the IVF28 cultivar was considered the least favored for the growth and reproduction of T. urticae mites, and such differences of mite performance might be related to the leaf thickness, instead of trichome density or stomatal density.
Speech privacy measurements and metrics
Authors: Good Kenneth W.
Published: April 2019

What is the current state of speech privacy measurements and metrics for built environments? This paper will provide an update on findings from the TCAA Speech Privacy Subcommittee. We will explore the uses, pros, cons, and appropriateness of Speech Privacy Potential (SPP) speech Privacy Index (PI) and Speech Privacy Class (SPC).
Speech privacy comparison of metrics
Authors: Good Kenneth W.
Published: April 2019

How do different speech privacy metrics compare, what are the correlations and differences, and what might we conclude from them? This paper will start with the noise reduction results from several common architectural assemblies. From those results, we will calculate each of the popular speech privacy metrics. Finally, we will explore the correlations and differences of the results.
The ultrasound transmissible lung: Impact of acoustic conditions in flooded lung on therapeutic ultrasound applications for lung tumour treatment
Authors: Wolfram Frank , Lesser Thomas G.
Published: April 2019

For minimal invasive treatment of Lung Cancer and Metastases, thermal ablation is a valuable tool in case of in-operability. Such a radiofrequency (RFA) is widely used despite its noticeable complication rate. The use of non-invasive modalities such as High Intensity Focused Ultrasound (HIFU) would be beneficial in lung, if acoustically transmissible. For such purposes, One Lung Filling (OLF) was developed, which replaces air with the saline content in lung. Suppositious, acoustic conditions in such a saline tissue compound might be different than in solid tissue and impact the HIFU ablation process in lung. Therefore, our work was dedicated to develop a valid acoustic model of lung in flooded conditions and validate it with findings on the HIFU interaction during OLF on preclinical models. Acoustic parameters were determined using a broadband transmission technique which showed atypical but superior conditions for ultrasound transmission through lung. Heat induction was simulated based on the derived parameters in an acoustic-thermal solver using KZK and Penne‘s bioheat equation (BHTE). Results showed good agreement to the measurement where ablative temperatures are induced in central lung cancer, while lung parenchyma stayed unaffected thermally and due to cavitation up to intensities of 9.500 W cm−2 (p— 9.1 MPa). Based on those findings, future directions for clinical application of therapeutic ultrasound during OLF in lung will be discussed.
Evaluating patient and staff perceptions of soundscape conditions within three hospitals
Authors: Bliefnick Jay , Ryherd Erica E.
Published: April 2019

Hospitals can present challenging soundscapes due to the continuous activity found within these environments. Routinely, this leads to poor perceptions of acoustical conditions from both patients and staff, such as in nationally reported HCAHPS patient surveys or hospital-administered staff surveys. In fact, it has been found that patient satisfaction of in-room soundscape conditions is highly related to the overall hospital rating and that staff job performance and satisfaction can be negatively affected by the acoustical environments in which they work. This research addressed these issues by collecting acoustical measurements within 38 patient rooms from 11 units of three individual hospitals, comparing results with patient and staff survey information. Data collected included 24-h occupied sound monitoring of patient rooms and nursing stations, unoccupied BNL sound levels from 20 patient rooms, and impulse response measurements of hospital unit hallways. Results from statistical analyses between measured acoustical data and patient/staff surveys will be reported, along with lessons learned applicable across all three hospitals. Taken as a whole, this study provided new insights into patient and staff perceptions of hospital noise, and could ultimately aid in the design process of new hospitals to improve patient and staff satisfaction.
Impacts of noise on staff cognitive performance in a hospital emergency department
Authors: Zaman Khaleela , Dodds Peter , Xiang Ning , Barach Paul
Published: April 2019

The soundscape of a typical modern hospital emergency department is undoubtedly noisy. Noise-related stress can contribute to human error, adverse medication events, and physician burnout and may negatively affect physicians’ mental health and limit clinicians’ ability to provide high-quality patient care. Previous studies have revealed average sound pressure levels for hospitals worldwide to be in significant excess of the World Health Organization firm guidelines. However, neither sound pressure level measurements nor loudness evaluations provide enough insight into the problem or potential solutions. Noise sources in hospitals include monitor alarms, overhead paging, echogenic surfaces, trash bins, ring binders, and patient crying out, among others. These sounds can be abrupt, yet not sustained. In order to evaluate the impact of hospital staff distraction and propensity for human error due to noise, the authors have conducted research at a busy, urban emergency department. The effects of various sonic occurrences on the cognitive load and working memory of physicians operating in the emergency department were assessed using binaural augmented acoustic environments as the backdrop for cognitive executive function evaluations. This paper discusses the methods for the binaural augmentation, cognitive testing, and initial results and offers interpretation and potential solutions to address these results.
Soundscape in dementia care environment
Authors: Talebzadeh Arezoo , Behboudi Ramin , Iaboni Andrea
Published: April 2019

Noise is an important sensory stimulus in any environment, especially in unfamiliar settings. Noise is impossible to ignore, and any disturbing noise or constant sound can be agitating, disturbing, and confusing for people who cannot escape the environment. People with dementia may already feel disoriented, isolated, and confined inside care facilities; uncontrolled sound can add to their anxiety and distress. Soundscape refers to the human perception of the auditory environment in context; it relies not only on the subjective quality of sound by quantifying the sound level but also the objective quality of the auditory environment based on people’s perception. The aim of this study is to describe the soundscape of the Specialized Dementia Unit at the Toronto Rehabilitation Institute, through data collection and observation, and to evaluate the quality of soundscape. Results show that the overall sound level (dB) of the unit is higher than recommendations, and also, the observation study shows that higher sound level not necessarily results in negative atmosphere, such as chaos or agitation. The findings prove a need for further study on the relation between the sound level and the perception of sound in dementia care units, which can foster improvement in quality of life for residents and staff.
Beamforming and range-migration localization algorithms using the retrieved Green's function
Authors: Denis Max , Collier Sandra L. , Noble John , Alberts W. C. Kirkpatrick , Ligon David , Sim Leng , James Deryck D. , Reiff Christian G.
Published: April 2019

In this work, the localization of acoustic noise sources and scatterers in an outdoor environment using Green's function retrieval methods is presented. Of particular interest is the implementation of cross-correlation and multidimensional deconvolution into localization algorithms. Conventional beamforming and range-migration algorithms, implemented with Green's function retrieval methods, are compared as localization techniques for an array system. The accuracy of both algorithms to reconstruct the position of targets (noise sources and scatterers) is investigated. Additionally, the added localization enhancements using the retrieved Green's functions are discussed.
Cortical effects on spatial tuning to speech in background babble
Authors: Ozmeral Erol J. , Palandrani Katherine , Eddins David A. , Eddins Ann C.
Published: April 2019

The ability to understand speech in complex backgrounds often relies on spatial factors that contribute to forming discernible auditory objects. From stimulus-evoked onset responses in normal hearing listeners using electroencephalography (EEG), we have shown measurable spatial tuning to moving noise bursts in quiet, revealing a potential window into cortical object formation. However, it is still unknown whether comparable effects are observed with speech stimuli, and whether and how much the presence of noise disrupts EEG responses to moving speech. To test whether the presence of noise has deleterious effects on object formation and potential selective auditory attention, we measured cortical responses to moving speech in the free field with and without background babble (+6 dB SNR) during both passive and active conditions. Active conditions required listeners to respond to the onset of the speech when it occurred at a new location, while indicating yes or no to whether the stimulus occurred at a block-specific location. We discuss in detail the effect of noise and attention on spatial tuning to speech stimuli as measured by the magnitude and latencies of the N1, P2, and P3 components at primary and secondary auditory regions of interest.
Ultra-low frequency vertical vibration isolators for absolute gravimeters
Authors: Wu Kang , Yao Jiamin , Wang Guan , Li Gang , Wang Lijun
Published: April 2019

High-precision absolute determinations of gravitational acceleration g provide important data for many fields such as metrology, geophysics, and geological exploration. In absolute gravimetry, vibrational noise from seismic and other environmental disturbances is one of the limiting factors. Several types of ultra-low vertical vibration isolators have been developed in Tsinghua University. The first one is a passive isolator based on LaCoste spring linkage and can achieve a natural period up to 32 s. The second one is an active isolator employing a two-stage beam structure. The upper beam is suspended from the frame with a hex spring, and the lower beam is suspended from the upper one using a zero-length spring. A feedback circuit is equipped to keep the angle between the two beams at a fixed value. The isolator can achieve a natural period of 100 s. The last one is an active isolator based on a two-stage structure, in which geometric anti-springs are used to support the proof mass. The volume of the isolator is greatly decreased, and the allowable load is increased while maintaining a natural period more than 15 s.
Deployable tessellated acoustic array with a curved Miura-ori pattern for ultrasound focusing in multilayered media
Authors: Zou Chengzhe , Harne Ryan L.
Published: April 2019

High intensity focused ultrasound (HIFU) has been successfully applied to treat cancers in clinical settings. In such treatment, the ultrasonic transducer projects focused ultrasound to the diseased tissues for thermal ablation. Nevertheless, the absorption, diffusion, and reflection that occur on the propagation path of ultrasound may reduce the effectiveness of HIFU. In order to overcome this challenge, a concept of origami-inspired deployable tessellated acoustic arrays may be leveraged. Fueled by large portability, the array may be compacted for insertion to the body and guidance to the point of care where the deployed array is then used for treatment. Such a vision requires understanding how wave propagation behaviors from reconfigurable tessellated transducer arrays are tailored in a multilayer environment. Here, the curved Miura-ori tessellation is used to approximate the arc shape for focusing. An analytical modeling framework is extended to investigate the new wave propagation behaviors encountered in biological-like media. Using the analytical tool, the tessellated acoustic array is compared with the ideal arc transducer, and the results indicate that the proposed concept may be comparable with an ideal case in focusing. In addition, the deployability of the tessellated acoustic array is confirmed through experimental efforts in a controlled multilayer environment.
Effect of a soft sediment layer over elastic basement on normal mode dispersion
Authors: Potty Gopu R. , Miller James H , Bonnel Julien
Published: April 2019

The effect of shear on dispersion of acoustic normal modes was investigated in a previous study (Potty and Miller, 2010). Modal dispersion was calculated using a bottom model consisting of a liquid layer over an elastic basement. The modal travel times corresponding to the Airy Phase regions were found to be extremely sensitive to shear. Simple inversion schemes were developed to estimate the shear speed in the sediment by comparing theoretical predictions with experimental data. Modal dispersion characteristics of broadband data collected during experiments conducted in Middle Atlantic Bight and New England Mud patch were analyzed, and bottom shear speeds were estimated. The estimated shear speeds were also compared with shear speeds calculated from core data. In this study, the bottom model will be revised to include a soft sediment layer over the elastic basement. The modal dispersion will be calculated using this bottom model corresponding to the New England Mud patch environment using propagation models such as ORCA and KRAKENC. The effect of the addition of the soft mud layer on dispersion of lower order modes will be investigated and presented. [Work supported by the Office of Naval Research.]
Multiphonic modeling using impulse pattern formulation
Authors: Linke Simon , Bader Rolf , Mores Robert
Published: April 2019

Multiphonics, the presence of multiple pitches within the sound of wind-instruments can be produced in several ways. Either complex fingerings are used or the blowing pressure is very low or very high. Such multiphonics can be modeled by the Impulse Pattern Formulation (IPF) proposed previously [R. Bader, Nonlinearities and Synchronization in Musical Acoustics and Music Psychology (2013)]. This top-down method assumes musical instruments to work with impulses which are produced at a generator, travel through the instrument, are reflected at various positions, are exponentially damped, and finally trigger or at least interact with succeeding impulses produced by the generator. While modeling sounds produced at blowing-threshold, the IPF fully captures transitions between regular periodicity at nominal pitch, bifurcation scenarios, and noise, just like regular instruments do, when multiphonics appear in the transition regime. Using IPF, complex fingerings translate to multiple reflection points at open finger holes with different reflection strengths. Here, complex multiphonics can be modeled. The IPF can also synthesize multiphonic sounds when applying the typical impulse form of wind instruments.
Soundscape, traffic safety, and requirements for public health
Authors: Schulte-Fortkamp Brigitte
Published: April 2019

In October 2018, the World Health Organization has published the Noise Guideline for the European Region strongly focusing on health effects caused by noise from different sources as transportation (road traffic, railway, and aircraft) noise, wind turbine noise, and leisure noise. As outlined in the Introduction, they “provide robust public health advice underpinned by evidence, which is essential to drive policy action that will protect communities from the adverse effects of noise.” Otherwise, the new technology in the development of electrical vehicles causes regulations calling for safety reasons for alert signals that may be counterproductive with regard to a harmonic and healthy soundscape. Regulations and needs will be discussed with respect to the public health recommendations on exposure to environmental noise and soundscapes.
Inter-array coherence-based identification of static acoustic clutter sources
Authors: Alberts W. C. Kirkpatrick
Published: April 2019

In multi-array acoustic detection and tracking applications, there often exist valid acoustic sources that are unwanted because of their position or nature, e.g., generators and air-handling equipment. During a tracking scenario where desired targets can be moving and/or piecewise static, the presence of these clutter sources can negatively impact the localization of a desired target by interrupting a track or generally increasing the noise floor local to an array. In directions away from the clutter source, beamforming methods onboard an array, e.g., minimum variance distortionless response, can be used to suppress the signature of the unwanted source. However, when a desired target passes through the azimuth of a clutter source, beamformers may fail to separate the desired source from the clutter. Here, inter-array coherence between beamformed solutions will be used to identify a static source by its properties in order to remove the clutter source as a potential target in a tracking application. Acoustic data on clutter sources measured by multiple microphone arrays separated by tens of meters will be discussed.
Multidimensional signal detection theory: Theoretical issues and empirical applications
Authors: Silbert Noah H.
Published: April 2019

Signal detection theory (SDT) provides a powerful set of tools for modeling choice data in a wide variety of domains. Fundamental to SDT is the distinction between noisy evidence and deterministic response selection. Multidimensional signal detection theory (MDSDT, aka general recognition theory) extends the basic concepts of SDT so that they are applicable to more complex tasks and data. Building on the SDT foundation of noisy evidence and deterministic response selection, MDSDT adds multiple ways in which dimensions may (or may not) interact. The additional complexity of multiple dimensions both broadens the range of applications of these tools and presents unique challenges. I will discuss the origins of MDSDT, a number of empirical applications of MDSDT in speech and hearing sciences, and some recent theoretical developments, focusing on model mimicry and identifiability and multilevel extensions of the basic model.
Specificity and generalization in perceptual adaptation to systematic variation in speech
Authors: Nygaard Lynne C. , Tzeng Christina
Published: April 2019

A signature problem in our understanding of spoken language processing is listeners’ perceptual constancy in the face of considerable variability in the instantiation of linguistic form. Abundant evidence now suggests that listeners are sensitive to the fine-grained structure of linguistic units that signal differences among talkers and track and adapt to this structure during the perception of speech. This talk will present data from a perceptual learning paradigm addressing both the constraints and flexibility of speech perceptual mechanisms. The aim was to address the degree to which exposure to variation in and expectations about talker- and group-specific attributes influence the degree of specificity and generalization in the perceptual adaptation process. Listeners were exposed to talker-dependent variation in a linguistic form, and expectations about talker characteristics were manipulated. The results suggest that listeners dynamically adapt to and encode systematic changes in the linguistic category structure as a function of expectation and appear to flexibly integrate talker- and group-dependent sources of variation into linguistic representation and processing.
A focused lens for measuring object response to modulated radiation pressure
Authors: Daniel Timothy D. , Kirsteins Ivars P. , Abawi Ahmad T. , Marston Philip L.
Published: April 2019

An ultrasonic lens was designed and tested for use in modulated radiation pressure experiments for the purpose of exciting and identifying the low frequency modes of objects in water. The lens was designed to produce a focused beam, and care was taken to minimize the spherical aberration introduced by the lens. This was done by carefully specifying the shape of the lens surface that was then machined using a computer-controlled lathe. The lens was placed in contact with an electrically excited piezoceramic plate. The quality of the focused sound field was tested and found to display properties predicted by simple models of the focal plane wave-field. The lens was then used to drive low-frequency modes of elastic objects in water using modulated ultrasonic radiation pressure in a way previously summarized involving a commercially made focused transducer [T. D. Daniel et al., J. Acoust. Soc. Am. 140, 3123 (2016)]. [Work supported by ONR.]
Introduction and overview—Libraries as a building type and reflections of multipurpose trends that have an acoustical impact
Authors: Paoletti Dennis
Published: April 2019

Libraries have developed from vast storehouses of bookshelves and hard covered manuscripts and literary materials to vibrant community centers and true multipurpose facilities, acoustically. This paper will discuss the: history of libraries, politics of libraries, architectural design of libraries, acoustical design of libraries, and the future of libraries. Examples of library projects ranging from main urban public libraries and university library systems to a number of smaller, standalone local community libraries. will provide interesting insight into the variety of activities that go on today in libraries that challenge the best of our acoustical design sensibilities and controls. Libraries share the basic acoustical parameters of many other building types, e.g., open plan spaces, offices and conference rooms, cafes, and even digital/multimedia and performing arts facilities. Lessons learned from challenging consulting efforts, especially when budgets are limited, will be explored and discussed.
Animals can measure acoustic flow; with the help of MEMS, we can too
Authors: Leahy Stephane , Abdelaziz Ahmed
Published: April 2019

Animals measure acoustic flow by using thin hairs. These hairs are essentially mechanical structures that are driven by viscous forces. Manufacturing thin hair-like structures is challenging, but we can think of other mechanical structures driven by viscous forces that can be manufactured more easily. Here, we discuss how MEMS technology can be used to fabricate a thin porous membrane and electrodes for measuring acoustic flow. We discuss the design trade-offs between performance, manufacturability, and product integration. For example, from a performance perspective, it is desirable that the membrane be as thin as possible, but from a manufacturing perspective, it is easier to make it thicker. We present preliminary results on early prototypes and discuss avenues to create a MEMS acoustic flow sensor that could be found in your smartphone within the next few years.
Hipposideros pinna motion patterns as an inspiration for dynamic biomimetic sensing
Authors: Jiu Pennine , Yin Anorexia , Müller Rolf
Published: April 2019

Many bat species, e.g., among the horseshoe bats (Rhinolophidae) and Old-World roundleaf-nosed bats (Hipposideridae), have highly mobile pinnae. Experiments with biomimetic reproductions of the pinnae shapes/motion patterns in these species have demonstrated a dynamic enhancement of the performance in acoustic direction-finding paradigms. It could hence be hypothesized that reproducing the full range of pinna mobility patterns in bats will allow realizing the full range of the animals' biosonar capabilities. Pinna motions in rhinolophid and hipposiderid bats have been shown to fall into two distinct categories, being either rigid rotations (i.e., changes in orientation but not in the shape itself) or deformations that change both pinna orientation and shape. To characterize the variability in the rigid rotations, landmarks on the pinnae of hipposiderid bats have been tracked using stereovision. From this kinematics data, an axis-angle representation of the pinna rotations was estimated. The results showed that the axes of pinna rotations can scatter widely in orientation, covering a range of directions that extends 180 degrees in azimuth and 180 degrees in elevation, about 40 times larger than the estimated error of the employed method. Hence, biomimetic reproductions of bat ear mobility should explore how to make use of such a variability.
Cochlea-inspired sonar signal processing
Authors: Todd Bryan D. , Müller Rolf
Published: April 2019

Many attempts have been made to model the signal transformations that occur in the mammalian cochlea, in particular with respect to modeling human hearing. Cochlea models that have been developed in the last few decades fall into several categories, e.g., electrical analogs, digital filter models, and incorporate different levels of complexity from entirely linear to strongly nonlinear. Similarly, the implementations used have included various numerical approaches as well as analog and digital hardware architectures. Mammalian hearing systems are known to be highly capable when it comes to analyzing sound from complex natural environments and soundscapes. It may hence be hypothesized that the signal transformations that occur in the cochlea play a critical role in facilitating these capabilities since the cochlea is positioned at the critical first stage of auditory signal encoding. The goal of the research presented here is to evaluate the signal transformations of the mammalian cochlea in the context of sonar signal processing, especially for automatic target recognition in difficult environments such as reverberant shallow water. The cochlea of bats could proof a suitable model for these applications since many bat species are known to be capable of solving demanding sonar tasks under difficult conditions and cluttered environments.
Atherosclerosis characterization using lipid-specific photoacoustic imaging and 4D ultrasound strain mapping in mice
Authors: Sangha Gurneet S. , Goergen Craig J.
Published: April 2019

Dual-modality photoacoustic tomography (PAT) and four-dimensional ultrasound (4DUS) imaging have recently been used study atherosclerosis progression in small animals. PAT uses pulsed laser light to induce acoustic waves and reconstruct lipid-specific compositional images of tissue. 4DUS captures dynamic volumetric information and can be used to estimate three-dimensional (3D) Green-Lagrange strain using a direct deformation estimation method. Here, we hypothesized that PAT/4DUS can be used to correlate changes in arterial strain and hemodynamics with lipid localization and density in animals that have undergone partial carotid ligation (PCL) induced-atherosclerosis. A 40 MHz transducer (Vevo2100, VisualSonics) and a ND:YAG pulsed laser (Surelite EX, Continuum) were used to image five apolipoprotein-E deficient mice that underwent PCL of the left carotid artery while being fed a Western diet. Animals were imaged using 4DUS at days 0, 1, 4, 7, 10, and 14 to obtain pulsed-wave Doppler for hemodynamic characterization and 4DUS images for strain mapping. At day 14 all animals were euthanized and 3D in situ PAT images of the left carotid artery were acquired using 1210 nm light. The results show that atherosclerotic lesions can be characterized via PAT to localize both lipid accumulation and density and 4DUS to identify regions of low strain.
Ascertaining the relationship between acoustic droplet vaporization, inertial cavitation, and hemolysis
Authors: Jahanpanah Newsha , Sharma Sneha , Mercado-Shekhar Karla P. , Su Haili , Palcich Hunter A. , Wanek Austin M. , Haworth Kevin J.
Published: April 2019

Mechanical stress associated with inertial cavitation (IC) can cause hemolysis. The goal of this study was to determine whether hemolysis occurs during acoustic droplet vaporization (ADV) and subsequent microbubble activity. Perfluoropentane droplets were manufactured using an amalgamation protocol, diluted 30-fold in porcine whole blood, and pumped through a flow phantom maintained at 37 °C. Droplets were insonified with a 5 MHz focused transducer (peak negative pressures of 0.25 MPa to 4.25 MPa, pulse length of 40 cycles, and a pulse repetition frequency of 500 Hz). A 128-element array was used to monitor the nucleation of ADV and to record cavitation emissions. Free hemoglobin in the effluents was assayed to detect hemolytic activity. Hemolysis, IC, and ADV were detected at pressures of 2.25 MPa and higher. At 4.25 MPa, 0.38 ± 0.08% hemoglobin was released post-hemolysis. A positive linear relationship was observed between the percent hemoglobin released and IC dose. Due to the concurrence of ADV and IC, it was not possible to determine whether ADV causes hemolysis independent of IC. These findings should be considered when planning studies of biomedical application of ADV. [Work supported in part by an Acoustic Society of America Robert W. Young Award.]
Lewis center for the arts at Princeton University
Authors: Solway Joe , Eckersley Casey , Digerness Joseph , Patel Raj
Published: April 2019

The opening of Princeton’s Lewis Center for the Arts in the Fall 2017 provided much needed performance and teaching spaces for the Theatre, Dance and Music programs at Princeton University, including an acoustically isolated orchestral rehearsal room, black box theater, dance theater, dance and acting studios, and music practice rooms individually hung from the roof slab above. Achieving the right balance of aural connectivity and sound isolation was an important part of the design, ensuring the Center feels vibrant and alive, while allowing teaching, rehearsal and performance to occur without disturbance. A key component to this work was the use of the Arup Soundlab, used to simulate the predicted acoustic environment within the music, drama and dance spaces, allowing the Princeton faculty and administration to listen to these spaces, and through discussion with Arup and architects from Steven Holl and BNIM, make informed decisions on the acoustic requirements for the design.
Characterising maternal pitch contours used during interactions with infants at high and low risk for autism spectrum disorder
Authors: Woolard Alix , Lane Alison , Campbell Linda , Karayanidis Frini , Barker Daniel , Korostenski Larissa , Lane Shelly , Benders Titia
Published: April 2019

Infant-directed speech (IDS) is the speech register used when interacting with infants. Pitch contours are a salient aspect of IDS and facilitate infant language and socio-communicative development. Little research investigates pitch contours within the context of socio-communication or language deficits, such as infants at high-risk (HR) for Autism Spectrum Disorder (autism). The aim of this study was to characterise pitch contours used by mothers when interacting with HR infants compared to mothers interacting with low-risk (LR) infants. 18 mothers and their 12-month-old infant (12m, 6f) participated in 15-minute recorded interactions. Autism risk was assessed via parent and observer-report. Pearson product-moment correlations were performed to determine relationships between maternal pitch contours and autism risk. Increased risk for autism was associated with fewer utterances (r = -0.576, N = 18, p = 0.01) and fewer rising (r = -0.586, N = 18, p = 0.01), sinusoidal (r = -0.636, N = 18, p = 0.005), and flat contours (r = -0.679, N = 18, p = 0.01), and more complex (r = 0.584, N = 18, p = 0.01), rapid (r = 0.526, N = 18, p = 0.03), and u-shaped contours (r = 0.619, N = 18, p = 0.02). These preliminary data suggest that mothers of HR infants use different patterns of pitch contours than LR mothers. Further assessment of IDS used with HR infants is warranted to identify at what stage IDS patterns deviate between groups.
Linear and half order fractional viscoelastic equivalents of the extended Biot model
Authors: Chandrasekaran Sri Nivas , Holm Sverre
Published: April 2019

The extended Biot poro-viscoelastic model [Chotiros and Isakson, JASA (2014)] like the standard Biot poroelastic model is biphasic and predicts two compressional waves (fast and slow) and one shear wave. Taking squirt flow into account, the model introduces two additional relaxation modes apart from the Biot crossover relaxation mode (global flow). The frequency dependent relaxation processes and a high number of independent parameters make the finite element implementation and the inversion of parameters for reconstruction a challenge. To overcome this challenge, we identify single phase viscoelastic equivalents for all three wave solutions of the extended Biot model from its dispersion relations. Considering squirt flow and high-frequency turbulent flow, the fast compressional wave and the shear wave solutions at low frequencies are equivalent to a non-standard solid model with eight parameters (four springs and four dashpots) and six parameters (Three springs and three dashpots), respectively. At high frequencies, the Kelvin-Voigt model used for tangential contact stiffness (shear relaxation) leads to non-physical equivalents. Neglecting this shear relaxation mode, the fast compressional wave and the shear wave solutions at high frequencies are equivalent to a fractional half-order solid model of order three and two, respectively. Alternative models for tangential contact stiffness are discussed.
Analysis of BAER tests of Tursiops truncatus Montagu in comparison of captive males to naval trained males in the open ocean
Authors: Hanson Elizabeth , Scheifele Peter M.
Published: April 2019

Do captive Atlantic Bottlenose Dolphins, Tursiops truncatus Montagu, have impaired hearing? This study compared the AEP results from captive dolphins to those who are trained by the Navy in the open ocean. The dolphins removed from the wild and relocated to captive environments could have a reduced hearing range as a result of the transfer to an area with potentially increased baseline noise levels. Auditory Brainstem Response (ABR) tests were conducted with underwater acoustic stimuli projection and reception in both the captive and the Navy dolphins. Tursiops truncatus Montagu has a range of hearing from 0.1-120 kHz. The hearing of dolphins that were born in captivity was closest to the naval dolphins in the ocean compared to those who were rescued from the wild. Captive dolphins were exposed to a constant 0.1-kHz noise levels for a brief period of time. This may potentially have had an effect on the latency of the peaks I-V and the correlating troughs in their ABR waveform. The results of this study can be used to assess auditory health of marine mammals and to determine the effect of anthropogenic noise levels whether in captive or natural marine mammal environments.
Sono-photoacoustic theranostics using phase-changing contrast agents
Authors: Li David S. , Lachowski Kacper , Pelivanov Ivan , Matula Thomas , O'Donnell Matthew , Pozzo Lilo
Published: April 2019

Phase-change contrast agents are low boiling point liquid perfluorocarbon droplets that can be vaporized to form larger microbubbles. Droplet vaporization can be used for both imaging and therapy. Sono-photoacoutics is a non-linear imaging method that uses simultaneous optical and acoustic pulses to activate phase-change contrast agents. By combining photothermal heating from a laser pulse and the negative pressure from an acoustic pulse, lower droplet activation thresholds are achieved than from either source alone. In this study, we demonstrate in an in vitro model that sono-photoacoutics activation of polypyrrole coated perfluorocarbon droplets can be used to disrupt 2-cm long fibrin clots to restore flow. Polypyrrole coated droplets under 200 nm in diameter were introduced upstream and allowed to diffuse into the clot. A 1.24-MHz single element transducer coaxially aligned with a 1064-nm pulsed laser was used to scan the clot, activating any agents within the clot. Agent activation was quantified using passive cavitation detection, while flow was monitored using a digital balance. Our results show that the droplets can freely diffuse into fibrin clots and SPA activation can restore approximately 25% of the flow.
Acoustic wave scattering from dynamic rough sea-surfaces using the finite-difference time-domain method
Authors: Higgins Alex , Siderius Martin
Published: April 2019

Numeric models for underwater acoustic propagation typically assume the sea-surface to be either perfectly smooth or rough but “frozen” in time. For long sonar signals on the order of tens of seconds, the sea-surface can interact at many different wave displacements over its duration. This causes anomalies in the received signal which introduces additional transmission losses and Doppler effects. The impact of including roughness and motion of the sea-surface on sonar systems is investigated using the finite-difference time-domain (FDTD) method. The FDTD method is a numeric technique that is well suited for modeling boundary roughness and motion. This is due to its ability to directly configure complex boundary conditions in the surrounding simulation grid and full pressure wave propagation in the time-domain. The rough, time-evolving sea-surface is modeled using a Pierson-Moskowitz (PM) frequency spectrum which is simple to implement and defined using just wind speed and direction. The results from FDTD simulations of static rough sea-surfaces are compared to a previously established integral solution method to evaluate the validity of the approach. Agreement is also demonstrated for FDTD simulations of a dynamic rough sea-surface and a theoretic statistical model. [Work supported by the Office of Naval Research.]
Autocorrelation models of pitch perception: In memory of ray meddis
Authors: Yost William , Patterson Roy D.
Published: April 2019

About 60 years ago, Licklider (1951, Experientia) described a qualitative model of autocorrelation that appeared to explain complex pitch perception. However, it was almost 40 years later before, Slaney and Lyon (1990, ICAASP) and Meddis and Hewitt (1991, JASA) incorporated autocorrelation into computational auditory models to test Licklider’s model of pitch perception. The Meddis and Hewitt frontend combined a level-dependent gammatone filterbank with Meddis’ (1986, JASA) inner hair-cell model. The “autocorrelograms” it produced revealed the temporal regularity of simulated auditory-nerve interspike intervals that occur in response to complex stimuli. The model was/is remarkably successful in accounting for a large set of complex pitch perception data. The model emphasizes the temporal structure of the neural information produced by a complex sound, in contrast to models that use a simple spectral representation of the resolved harmonics of a complex sound. Today, those who model complex pitch perception either use an autocorrelation-like approach or argue why such an approach does not work. The Meddis-Hewitt model is almost always considered in these modeling efforts. This presentation will describe the Meddis-Hewitt model and discuss its lasting effect on the study of complex pitch perception. [Work supported by NIDCD and Facebook Reality Labs grants to WAY.]
Matching pitch gestures to visual trajectories as a function of acoustic scales
Authors: Lembke Sven-Amin
Published: April 2019

Auditory gestures are commonly used in music and sonification, although little is known about their perceived shape. A listening experiment aimed to study how pitch-based gestures that rely on different acoustic scales are perceived and matched to analogous visual trajectories. Four scales were studied, varying in curvature on a linear time-vs-frequency plane: linear frequency in Hz, equivalent-rectangular-bandwidth (ERB) rate, an exponential function twice the curvature of ERB rate, and a logarithmic function with inverse curvature to ERB rate. The pitch-glide stimuli were based on filtered noise and spanned two octaves. These glides were tested below and above a 1-kHz anchor, ascending and descending in pitch, and for two durations, all serving as independent variables (IVs). An interactive visual trajectory served as the dependent variable. Participants matched the visual shape to the perceived auditory gesture, along a continuum from exponential to logarithmic curvatures, including a straight line. Only three of the four acoustic scales were compared and rated in a single trial, which allowed to assess contextual bias across all possible combinations. Preliminary data suggest that pitch glides based on the ERB rate match a straight line best, while linear-frequency glides are perceived as moderately logarithmic trajectories. These two scales, however, exhibit some contextual variability, whereas these trends seem robust across the investigated IVs, intra-subject consistency appears to strongly depend on listening expertise.
Living probes as calibration standards for acoustic microfluidics
Authors: Kim Minji , Huff Emma , Bayly Philip , Meacham J. Mark
Published: April 2019

Acoustic microfluidics is promoted as an enabling technology for numerous applications in medicine and biology; however, adoption of these solutions in clinical and industrial settings is hampered by inconsistent performance and poor reproducibility. Though computational modeling and laboratory-scale demonstrations anticipate significant advantages for acoustofluidic unit operations including mixing, sorting/separation, and isolation, few technologies have realized this potential. A lack of standard tools and methods for assessing and comparing device performance represents a critical barrier to progress in the field. Here, we introduce a living probe that allows accurate and dynamically responsive measurement of the acoustic pressure within a device. Motile unicellular alga Chlamydomonas reinhardtii (CR) probe their environment and naturally swim against an imposed force field to fill complicated shapes. Steady-state distributions of swimming cells can be related to the field shape and strength to more completely describe the pressure field (versus passive particles that reach terminal distributions at nodal locations). Significantly, CR cells continuously respond to their environment, which enables real-time observation of the system response to varying operating conditions (e.g., frequency and/or drive voltage). We present the results that demonstrate correlation of CR cell distributions with pressure fields in simple one- and two-dimensional shapes, as well as more complex architectures.
Speech perception is influenced by the speech rate of both attended and unattended sentence contexts
Authors: Bosker Hans Rutger
Published: April 2019

Speech perception is influenced by the temporal properties of the surrounding acoustic context. These temporal context effects (TCEs) are contrastive: a heavily reduced target sound [tɛɹ:] is perceived as "long” “terror” when preceded by fast speech but as “short” “tear” in slow speech. I will introduce earlier studies demonstrating that TCEs involve domain-general processes arising early in perception, driven by neural oscillations entraining to the syllabic rhythm of speech. If TCEs arise early in perceptual processing, this raises the question whether TCEs are modulated by selective attention. That is, is speech perception in a “cocktail party” situation influenced by attended speech rates only or also by the speech rate of unattended talkers? In three experiments, participants were presented with two simultaneous context sentences, one in each ear, followed by diotic ambiguous target words. The speech rate of both attended and unattended talkers was found to equally influence target categorization, regardless of whether the attended context was in the same or different voice than the target, and even when participants could watch the attended talker speak. Therefore, TCEs are immune to selective attention, suggesting that TCEs largely operate at a level in the auditory processing hierarchy that precedes attentional stream segregation.