bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of the Pipe in Pipe vibration software model to determine ground-borne noise and vibration levels above construction tunnels and the determination of end corrections for different train operating scenarios
Authors: Parry Graham , Summers Steve , Yates David
Published: May 2014

The London Crossrail project requires that re-radiated noise from the construction of the tunnels should achieve exceptionally stringent criteria with respect to groundborne noise and vibration. The challenge has been to implement robust vibration modeling for the movement of construction trains within the tunnel in order to derive noise levels within sensitive properties (including recording studios) above the tunnel. The Pipe in Pipe (PiP) software model (which is based on elastic continuum theory) developed by Hunt and Hussein has been modified and refined empirically utilizing the measurement of exceptionally low vibration levels emanating from the temporary underground construction railway track. The paper describes the extensive and challenging monitoring and modeling which been carried out. The study represents the first rigorous method of determining noise and vibration at properties above the tunnel from construction trains for the Crossrail project, with an associated detailed validation exercise in line with ISO 14837-1 `Mechanical vibration— Ground-borne noise and vibration arising from rail systems'. A combination of modeling and vibration measurements were used to inform the predictions of groundborne noise levels, which can be adjusted to replicate the behavior of other track and rail support types.
The acceptability of railway induced vibration in residential environments
Authors: Woodcock James , Peris Eulalia , Sica Gennaro , Sharp Calum , Moorhouse Andy T. , Waddington David C.
Published: May 2014

The aim of the study presented in this paper is to investigate the use of self-reported acceptability for assessing the human response to environmental vibration in residential environments. The human response to environmental stressors such as noise and vibration is often expressed in terms of exposure-response relationships that describe annoyance as a function of the magnitude of the vibration. These relationships are often the basis of noise and vibration policy and the setting of limit values. This paper takes a different approach by expressing exposure-response relationships for vibration in terms of self-reported acceptability. It is argued that exposure-response relationships expressing acceptability as a function of vibration exposure will complement existing relationships for annoyance in future policy decisions regarding environmental vibration. The results presented in this paper are derived from data collected through a large scale (N = 1431) socio-vibration survey conducted in the United Kingdom, the aim of which was to derive exposure-response relationships for vibration in residential environments. The sources of vibration considered are railways and construction.
Vibration, noise, and their interacting contributions toward sleep disturbance
Authors: Smith Michael G. , Croy Ilona , Hammar Oscar , Persson Waye Kerstin
Published: May 2014

The market share of goods traffic operating on the European rail networks is expected to almost double from 2001 to 2020. Nocturnal time slots are expected to play an important part in facilitating this increase and as such sleep disturbance in residential areas is expected to be the most significant hindering factor. Little data currently exist that may be utilized to investigate the potential impact. Within the European project CargoVibes we experimentally investigated sleep disturbance due to vibration and noise arising from freight trains. An experimental trial was conducted involving 23 healthy subjects sleeping for six nights; a habituation night, a control night, and four nights with combinations of vibration and noise exposure. The primary objective was to examine the contribution of each exposure, and investigate how vibration and noise contribute individually and simultaneously to human response. The secondary aim was to determine whether increased numbers of events relative to previous work using 20–36 trains further impacted on sleep. Physiological parameters including sleep stage, cardiac activity, and cortical arousals were obtained using polysomnography and questionnaires were administered to obtain sleep quality data. Results indicate that vibration directly contributes to sleep fragmentation. The findings shall be further discussed at the conference.
Ixpantepec Nieves mixtec question intonation
Authors: Chung Younah , Ritchart Amanda
Published: May 2014

Ixpantepec Nieves Mixtec (INM) is posited to have a three-way lexical tone system and lexical stress. However, no known work has investigated whether INM makes use of F0 intonationally. Our study addresses this gap and seeks to contribute to the typology of tone-intonation interactions. We recorded both polar and wh-questions. For polar questions, we analyzed the F0 from one female speaker. The speaker produced question-answer (Q&A) pairs, where the object of transitive verb phrases appeared in both the interrogative and declarative sentences, and differed in its lexical tone. The F0 of every vowel was measured to determine if lexical tones vary depending on whether they occur in an interrogative or declarative sentence of the Q&A pair. Pitch raising is the only significant difference (p < 0.01) between the Q&A pair; both high and low lexical tones have higher F0 in the interrogative compared to the declarative. For wh-questions, a qualitative analysis was done using interview data from a male and female speakers. A quantitative analysis is also underway. The Q&A pairs had similar pitch contours and absolute F0 values; thus, no wh-question intonation or tone-intonation interaction was found. Implications for intonational typology in languages with lexical tones will be discussed.
An acoustic analysis of advanced tongue root harmony in Karajá
Authors: Fulop Sean A. , Warren Ron
Published: May 2014

Recent phonological analysis of Karajá, a Macro-Jê language of Brazil, claimed that the language's vowel system evinces advanced tongue root (ATR) harmony [Ribeiro, “ATR harmony and palatalization in Karajá,” Santa Barbara Pap. Linguist. 10 (2000)]. Despite this, the phonetic facts about these vowels have never been published, which has left the only claim that ATR operates in any American language subject to controversy. The use of tongue root advancement can never be completely established without articulatory investigation (e.g., MRI scan), but we here provide an acoustic analysis of two native Karajá speakers, which examines the correlates of [ATR/RTR] in four pairs of vowels. An ATR vowel involves expansion of the pharyngeal cavity by moving the base of the tongue forward and/or lowering the larynx during vowel production, and being generally involved in vowel harmony, contrasts with a retracted [RTR] version of the vowel. Acoustic correlates of tongue root advancement generally include a lowering of the frequency of F1 as the pharyngeal cavity expands, together with changes in spectral timbre as measured by the relative formant amplitudes. Particularly, the amplitude of F1 is frequently greater in [ATR] vowels when compared with [RTR] vowels [Fulop et al., “An acoustic analysis of the tongue root contrast in Degema vowels,” Phonetica 55, 80–98 (1998)], and this will be used to illuminate the phonological claims.
Linearly diverging vocal folds and the Coanda effect
Authors: Haas Jesse , Pelorson Xavier , Hirschberg Avraham
Published: May 2014

We would like to verify whether the Coanda effect has a significant impact when incorporated into theoretical vocal fold models that assume a piecewise linear shape of the vocal fold walls, as many do. We model the intraglottal flow with the equations of Thwaites. Thwaites boundary layer theory gives simple criteria for the glottal jet separation point if the vocal folds diverge linearly, and even validates well-known empirical observations for the jet width at flow separation. We test this criteria against flow experiments with rigid vocal fold replicas. The experiments involve symmetric and asymmetric vocal fold configurations, as well as steady and unsteady flow. We then validate the significance of the predicted Coanda effect on several numerical models of human vocal folds. We test the significance of the effect both on mechanically symmetric vocal fold models and on ones with mechanical asymmetries. We find limited effects on symmetric vocal folds and varying degrees of impact on asymmetric vocal folds.
Measures of spectral tilt in Shanghainese stops and glottal fricatives
Authors: Koenig Laura L. , Shi Lu-Feng
Published: May 2014

Shanghainese differs from other major Chinese dialects in having a three-way contrast among stop consonants. Although phonological descriptions often label these sounds as voiceless aspirated, voiceless unaspirated, and voiced, in contemporary Shanghainese the “voiced” category is not typically produced with closure voicing in initial position. Rather, the vowel onset appears to be characterized by breathy voicing, as demonstrated by acoustic, aerodynamic, and transillumination data. Past studies have been limited to few speakers. This study presents preliminary data of a large-scale study of the Shanghainese stop system as well as the voicing contrast in glottal fricatives, another unusual feature of the language. Data have been collected from 20 male and female native speakers. Measures are made of voice onset time (for the stops), and three measures of spectral tilt (for stops and glottal fricatives): The relative amplitudes of (a) the first two harmonics (H1-H2); (b) H1 and the first formant (H1-A1); and (c) H1 and the third formant (H1-A3). Spectral tilt measures are taken at phonation onset and 50 ms into the vowel. Preliminary analyses suggest that all three spectral measures may lend insight into the nature of the source distinction among the stops as well as the glottal fricatives.
An acoustic analysis of lexical stress in non-words in Uyghur
Authors: Yakup Mahire
Published: May 2014

Previous research examined the stress pattern in Uyghur, a Turkic language, using real words and found that Uyghur used the duration as a stress cue but not F0, and the intensity was moderated by syllable types. In order to avoid vowel lengthening in the real words, the non-words (DOSdos vs. dosDOS or DOdo vs. doDO, capitalized as stressed) were used, in which the syllable types (CVC syllable and CV syllable) and vowels (a, u, i, o, ø, y) were controlled. In the production experiments, speakers were clearly instructed that the capitalized ones were stressed and lower-cased as unstressed syllables. All target words were embedded in the same carrier sentence (e.g. ‘I will say X now.'). In the production of ten female native Uyghur speakers, average fundamental frequency, duration, average intensity, and first and second formant frequencies for vowels were collected in the accented and unaccented syllables. The results showed that there were significant differences in duration and intensity between stressed and unstressed syllables. The fundamental frequency differences were associated with word final positions rather than stress positions. Vowels are centralized in the unstressed position. The present acoustic data suggest that native Uyghur speakers use of duration and intensity rather than F0.
Effects of predictability on vowel reduction
Authors: Whang James D.
Published: May 2014

High vowel devoicing in Japanese, where unaccented /i, u/ in a C1VC2 sequence reduce when both C1 and C2 are voiceless, has been studied extensively, but whether the target vowel is truly devoiced (oral gesture is maintained) or deleted completely (oral gesture and voicing are both lost) is still debated. This study examines the effects of vowel predictability on the degree of vowel reduction. Native Japanese speakers (N = 8) were recorded in a sound-proof booth reading sentences containing lexical stimuli. C1 of the stimuli were [k, ∫], after which either high vowel can occur, and [ϕ, s, ç], after which only one of the two is possible. Half of the stimuli contained a devoicing environment with a voiceless C2. Center of gravity, the amplitude weighted mean of frequencies present in a signal, was measured for the first half (COG1) and the second half (COG2) of C1. Results show that COG2 is significantly lower than COG1 for all consonants when a full vowel follows, as well as for [k, ∫] in devoicing stimuli. In contrast, COG remained stable for [ϕ, s, ç] in devoicing environments, suggesting a complete lack of vowel gestures. Predictable vowels, therefore, seem to delete, while unpredictable vowels devoice.
Effects of speaking mode (clear, habitual, slow speech) on vowels of individuals with Parkinson's disease
Authors: Buccheri Rebekah A. , Whalen Douglas H. , Strange Winifred , McGarr Nancy S. , Raphael Lawrence J.
Published: May 2014

This study examined the effects of three different speaking modes (clear, habitual, and slow speech) on speech production of individuals with and without Parkinson's disease. Twenty-one speakers (13 with Parkinson's, 8 Controls) read the Farm passage in habitual, clear, and slow speech modes. Acoustic analysis involving the assessment of the first and second formant frequencies was performed using: vowel space areas, vowel dispersions, /i-ɑ/ distances measures for both tense and lax vowels produced in each of the speaking conditions. Results revealed that for both groups, the vowel space areas were larger in the clear and slow conditions compared to habitual, with no difference between clear and slow for tense vowels. However, there was no significant difference across any of the speaking conditions for lax vowels. There was a significant difference in vowel dispersion measures, between the habitual and clear speech conditions and also the slow and habitual conditions. But there was no significant difference between the clear and slow conditions for vowel dispersions. With respect to /i-ɑ/ distance, there was a significant difference between the habitual condition and clear speech. Implications of these results will be presented for both Parkinson's disease subjects and normal controls.
Segmental and prosodic effects on intervocalic voiceless stop reduction in connected speech
Authors: Bouavichith Dominique A.
Published: May 2014

Descriptions of English and other languages have claimed that voiced and voiceless intervocalic stops are often lenited to fricatives and approximants in connected speech. Few acoustic analyses of factors that affect this reduction have been reported for American English [cf. Lavoie (2001), Tucker and Warner (2011)]. In this analysis, intervocalic voiceless stops produced in bisyllabic words during story reading are examined (participants N = 19). The first result shows that speakers never lenite voiceless stops to approximants, except when /t/ is produced as the approximant implementation of a flap. This shows that voiced and voiceless stop reduction behave differently. Second, stress and vowel reduction play an integral role: 33% of stops are produced as fricatives when stress is on the preceding syllable (e.g., “taco”); 4% when stress is on the following syllable (e.g., “account”). The rate of reduction is significantly lower when stops are surrounded by two full vowels and higher when they are followed by schwa. Third, fricative reduction is most common for /k/, since full closures may be most difficult in the velar region. This study will be compared to Bouavichith and Davidson's (2013) examination of voiced stops to provide a fuller picture of intervocalic stop reduction in American English.
Vowel and consonant effects on subglottal pressure
Authors: Demolin Didier , Gerbers Silvain , Hassid Sergio
Published: May 2014

The respiratory system is generally regarded as producing voluntary variations in intensity and perhaps in pitch, but not producing voluntary increases in pressure for particular sounds. All the changes related to individual segments, such as the drop in subglottal pressure that occurs after [h] or the increase in pressure during the [k] closure are considered to be aspects of tract aerodynamics, and not under voluntary control. They can be ascribed to variations in the resistance provided by the vocal folds to the outgoing air (the glottal impedance) or to variations in the stiffness of the vocal tract walls. This paper examines variations accompanying different vowels and consonants, and concludes that it is not only the Koreans who use greater respiratory effort to distinguish some sounds. The principal finding of this study was that there was a considerable difference in the subglottal pressure associated with the different vowels. Across all other variables, the difference in subglottal pressure between /a/ and /i/ is 1.65 cm hPa and between /a/ and /u/ is 1.76 hPa. Both these differences are highly significant (p < 0.0001) in a one way ANOVA. The difference between /i/ and /u/ is 0.11 hPa and is not significant (p = 0.303).
Phonetic marking of stance in a collaborative-task spontaneous-speech corpus
Authors: Freeman Valerie , Levow Gina A. , Wright Richard
Published: May 2014

While stance-taking has been examined qualitatively within conversation and discourse analysis and modeled using text-based approaches in computational linguistics, there has been little quantification of its acoustic-phonetic correlates. One reason for this is the relative sparsity of stance-taking behavior in spontaneous conversations. Another is that stance marking is embedded into a highly variable signal that encodes many other channels of information (prosody, word entropy, audience, etc.). To address these issues, we draw on varying subfields to build a corpus of stance-dense conversation and develop methods for identification and analysis of stance-related cues in the speech signal. In the corpus, dyads are engaged in three collaborative tasks designed to elicit increasing levels of investment. In these imaginary store inventory, survival, and budget-balancing scenarios, participants solve problems, but the conversation is otherwise unscripted. Based on limited previous work (Freeman, under review) and initial findings from our corpus, we predict that stance-marking employs hyperarticulation (or lack of reduction) analogous to topic or contrast focus but where reduction would be expected in the discourse structure. Stance-taking is expected to correlate with slower speaking rates, longer stressed vowels, more expanded vowel spaces, greater pitch excursions, and greater modulation of speech signal intensity.
The prosody-pragmatics interface: An acoustic analysis of contrasting Spanish varieties
Authors: Platz Ryan
Published: May 2014

Investigating correlations between communicative contexts and prosodic elements allows researchers to exploit the (perhaps inherent) connection on the prosody-pragmatics interface. Pitch accent models such as ToBi and RaR are helpful for a descriptive analysis, but categorization of different pitch contours can be subjective and rely on the eye of the investigator. Comparing the prosodic elements that define these models' categorization parameters would provide a better approximation of the intonation patterns across specific languages varieties and pragmatic contexts. This study investigates the prosody-pragmatics interface from an acoustic perspective in an analysis of native speakers of several Spanish varieties. Participants responded to 12 situations in which two pragmatic variables were controlled for (social distance, ranking of imposition). Responses were analyzed with a Praat script to capture pitch range, pitch span and speaking rate. Results do reveal a correlation between dialect and each suprasegmental variables, but an even stronger correlation between speaker and the contextual pragmatic variables was found, irrespective of dialect. These findings provide empirical evidence that prosodic elements of the speech signal are more relevant to the given pragmatic context rather than to speaker dialect traits, suggesting intonation patterns are constructed within a communicative context rather than within the speaker's community.
European project for achieving quieter oceans by shipping noise footprint reduction
Authors: Audoly Christian , Rousset Céline
Published: May 2014

There is a growing consensus among the scientific community for the need to mitigate underwater noise footprint due to shipping, in order to prevent negative consequences to marine life. In that context, AQUO project started in October 2012, in the scope of the FP7 European Research Framework, for three years duration. The final goal is to provide policy makers with practical guidelines and solutions, acceptable by shipyards and ship owners, in order to mitigate underwater noise due to noise radiation from ships. First, a general presentation of the project will be given, and the logical relationship between the tasks will be outlined. A key element is the development of a “Shipping noise footprint assessment tool,” derived from the software Quonops©. This tool can predict the noise map in a maritime area using real time information on ship traffic. Many other studies are undergoing, covering ship underwater radiated noise, propeller noise (including cavitation), and bio-acoustic experiments. The AQUO project team is composed of ship industry, specialized companies, a classification society, research centres and academics, allowing addressing the complexity of the topic. In a second part, some recent results from the project will be given. These will include, for example, the definition of indicators for the impact of shipping noise on marine life, results from vibro-acoustic measurements on several ships at sea, and results from bio-acoustic studies.
Alternatives to traditional probabilistic approaches for incorporating environmental uncertainty in ocean acoustics
Authors: Finette Steven I.
Published: May 2014

Quantifying environmental uncertainty and its corresponding mapping onto the acoustic field is a subject of considerable importance for underwater acoustics modeling and simulation. The ability to make accurate numerical predictions of basic acoustic quantities, as well as sonar system performance in complex ocean environments depends, in part, on objectively quantifying our imperfect knowledge of the waveguide properties. Over the past few years, a number of approaches have been considered to quantify uncertainty in ocean-acoustics modeling; these methods are grounded in some form of traditional probabilistic reasoning. While probability theory provides a natural framework for representing and quantifying environmental uncertainty, a significant amount of information must be available to specify density functions for the parameters and fields so that the corresponding acoustic field statistics can be computed. This talk will overview alternatives to traditional probability-based reasoning that have been introduced in research areas where conventional specification of probability distributions are not a practical means for describing uncertainty. [Work supported by base funding from ONR.]
Spatial uncertainty in higher fidelity acoustic models, and impact on model-data comparisons
Authors: Campbell Richard L. , Heaney Kevin D. , Abbot Phil , Emerson Chris J.
Published: May 2014

Acoustic propagation models, such as the parabolic equation (PE), are typically parameterized by a single source depth and one or more receiver depths and ranges. At the higher frequencies, propagation angles, and ranges enabled by advances in computer hardware and refinement of algorithms, the acoustic field predicted by the model can contain features at considerably finer scale than the resolution of the requested output points. The typical practice of simply sampling the field at the output points can introduce artificial large scale structure in the output, due to aliasing. However, averaging out the fine-scale spatial variability can also result in a misleadingly precise value for transmission loss (TL) at a given point. We show that reconciliation of acoustic model predictions with experimental data can be greatly improved by presenting the TL variability due to the expected uncertainty of source and receiver position within an otherwise deterministic model. Even with good estimates of source and receiver positions, this variability can be greater than that due to uncertainty in the model's environmental inputs. Model-data comparisons are demonstrated with examples from a recent ONR effort in the eastern Gulf of Mexico which included controlled TL measurements at 0.4–2 kHz in shallow water.
On the inversion of sediment density profile by the image source method
Authors: Drira Achraf , Guillon Laurent , Boudraa Abdel-Ouahab
Published: May 2014

Image Source Method is a recently developed method for geoacoustic inversion. Under the Born approximation, the reflection of a spherical wave above a stratified seafloor is modeled as the simultaneous emission of image sources, symmetric of the real one relatively to the layers. These image sources are detected and located by the use of Teager-Kaiser Energy Operator (TKEO), which amplifies sudden changes in signal amplitudes, and by a triangulation scheme. Time and arrival angle of the recorded signals coming from the image sources are the input values of the inversion algorithm which gives the thickness and sound speed of each detected sediment layer by the use of Snell-Descartes laws. The objective of the present work is to extend this method to the inversion of the sediment density profile. To this end, one supplementary data is required. Experimental amplitudes corresponding to arrival times of the reflected signals, detected by TKEO, are compared to theoretical ones computed by a numerical evaluation of the Sommerfeld integral. Having first inverted sound speed profile and neglecting absorption coefficient, density is the only remaining parameter and thus can be obtained. The effectiveness of this method is tested on both synthetic and real data.
Detectability of navigation obstacles with forward looking sonar in presence of boat wakes: Observations in Narragansett Bay
Authors: Yakubovskiy Alexander M. , Sharma Nabin S. , Zimmerman Matthew J.
Published: May 2014

A Forward Looking Sonar (FLS) is designed to detect obstacles ahead of a vessel. Detection performance of an FLS is affected by several environmental factors surrounding the sonar. Wakes generated by nearby vessels degrade the detection capability of an FLS. With more than 40 000 registered boats, Rhode Island's Narragansett Bay is a good example of a zone with heavy boat traffic where the performance of an FLS may be effected. FarSounder has collected vast amounts of data while testing and demonstrating its FLS sonars in Narragansett Bay. Using that data, this paper presents observations of FLS performance with and without boat wakes. In order to explain the sonar performance, a probability of wake presence in sonar field of view is estimated based on shipping density, wake size, and lifetime.
Optimizing eigenray generation for real time simulations
Authors: Fredricks Andrew J. , Martinelli Sheri
Published: May 2014

Real time simulation is a critical supplement to in-water testing for the assessment of naval system performance. Limitations exist on the number of independent runs, on geographical locations in which in-water tests can be performed, and on the amount of control experimenters possess over the test environment. Many systems have critical time-sensitive functionality (e.g., acoustic homing) which constrains the ability to produce realistic time series for injection; but a reduced fidelity solution can still be of use. Graphics hardware (GPU) has become a significant computing platform in its own right. Its application requires a mapping of the propagation algorithm to the GPU computing paradigm and careful tweaking to squeeze out maximum performance. We will look at taking from theory just what we need to hand-tune code for a GPU + CPU computing platform, and the limitations of a high speed, range dependent, eigenray code. We also consider a related approach that uses the resulting eigenrays to initialize an iterative method which updates the eigenray solution as the source and receiver update their relative positions. [Work funded by the Office of the Secretary of Defense, Test Resource Management Center's Resource Enhancement Project element of the Central Test and Evaluation Investment Program.]
Influence of short time scale water column fluctuations on broadband signal intensity
Authors: Eickmeier Justin , Mohsen Badiey
Published: May 2014

The KAM11 experiment was conducted in 100 m of water off the Western side of Kauai, Hawaii, in June/July, 2011 during which two identical bottom mounted tripods, separated by 1 km, transmitted reciprocal chirp sequences. A monitoring hydrophone was suspended at a depth of 25 m from the R/V Kilo Moana approximately midway between the tripod stations. Impulse response measurements at the suspended hydrophone show intermediate arrivals between direct-path/bottom-bounce and surface-bounce arrivals unique to only one tripod source. Focusing and defocussing of the intermediate arrivals show the influence of fluctuations in the sound speed profile over time scales from seconds to hours. Short term intensity variations arise from surface driven vertical undulations in the water column. Over longer time scales changes in the thermocline govern the evolution of the intermediate arrival. Data model comparison is conducted with ray tracing and parabolic equation modeling. [Work supported by ONR 322OA.]
Model and data comparisons of ocean acoustic intensity statistics in the Philippine Sea 2010 experiment
Authors: Ganse Andrew A. , Andrew Rex K. , Henyey Frank S. , Mercer James A. , Worcester Peter F. , Dzieciuch Matthew A.
Published: May 2014

The statistics of intensity fluctuations in dual-band, low-frequency, ocean acoustic transmissions across 500 km in the Philippine Sea 2010 experiment appear to be at odds with the standard micro-multipath theory predicting them. M-sequence encoded acoustic signals at 200 Hz and 300 Hz were transmitted for 54 h from a ship-suspended multiport source to a distributed vertical line array (DVLA) with 149 working hydrophones covering most of the 5500 m water column. Histograms of the received intensity fluctuations are approximately exponential. Intensity fluctuations at the two frequencies are strongly correlated. Scintillation indices and variances of log intensity are high (>1 and >5.57dB, respectively), suggesting the measurements are not yet in a saturated regime but still significantly scattered. However, for all this, the pulses received at the DVLA are virtually the same width as those recorded next to the source; no pulse spreading or arrival splitting is seen. So, the fading observed in the data does not appear to match this causal mechanism. To explore the connection with micro-multipath theory more fully, we compare the intensity statistics from the Philippine Sea 2010 data with those calculated both from simulated random oceans and from Flatté and Rovner's path integral theory. [Work supported by ONR.]
Acoustic characterization of polymer-encapsulated microbubbles with different shell-thickness-to-radius ratios using in vitro attenuation and scattering: Comparison between different rheological models
Authors: Xia Lang , Paul Shirshendu , Chitnis Parag V. , Ketterling Jeffrey , Sheeran Paul , Dayton Paul , Sarkar Kausik
Published: May 2014

Acoustic behaviors of five different polymer (polylactide) encapsulated microbubbles—PB127 (Point Biomedical), PH37, PH43, PH44, PH45 (Phillips Healthcare) with different shell-thickness-to-radius ratios (STRR) of 3.5, 30, 40, 65, and 100 nm/μm have been characterized. In vitro attenuation data were used to determine the interfacial rheological properties of their shells. Use of different models—Newtonian, viscoelastic, strain-softening, Marmottant, and Church—resulted in similar rheological properties. The shell elasticity and shell viscosity were found to increase with increasing shell thickness as expected. The nonlinear scattered response from these microbubbles were measured. Experimentally measured scattered subharmonic response were compared with the model predictions.
Microbubble spectroscopy of microbubble-loaded stem cells for targeted cell therapy
Authors: Kokhuis Tom , Skachkov Ilya , Naaijkens Benno , Juffermans Lynda , Kamp Otto , van der Steen Ton , Versluis Michel , de Jong Nico
Published: May 2014

Stem cells can be conjugated with targeted microbubbles to form highly echogenic complexes, dubbed StemBells. The complexes can improve stem cell delivery for the local repair of damaged cardiac tissue after a myocardial infarction through propulsion by acoustic radiation forces. While the first in-vivo tests hold great promise, the system would greatly benefit from a mapping of the acoustic parameter space. Here, we develop the theoretical background based on a modified Rayleigh-Plesset type equation to describe the dynamics of the StemBells in response to ultrasound. The complex is shown to resonate as a whole entity and resonance curves are constructed from numerical simulations resembling single bubble responses at a size that relates to the effective complex radius ~10 μm. Ultra high-speed optical imaging of single StemBell complexes at different frequencies using the microbubble spectroscopy method allows for a full characterization with excellent agreement with the developed model. Moreover, from the experimental resonance curves, we obtain values for the effective viscoelastic shell parameters of the StemBell complexes. These results have enabled the demonstration of the feasibility of manipulating StemBells inside chicken embryo microvasculature in an accompanying paper.
Hot Topics—Hidden hearing loss: Permanent cochlear-nerve degeneration after temporary noise-induced threshold shift
Authors: Liberman M. Charles , Kujawa Sharon G.
Published: May 2014

The classic view of sensorineural hearing loss (SNHL) is that the “primary” targets are hair cells, and that cochlear-nerve loss is “secondary” to hair cell degeneration. Our work in mouse and guinea pig has challenged that view. In noise-induced hearing loss, exposures causing only reversible threshold shifts (and no hair cell loss) nevertheless cause permanent loss of >50% of cochlear-nerve/hair-cell synapses. Similarly, in age-related hearing loss, degeneration of cochlear synapses precedes both hair cell loss and threshold elevation. This primary neural degeneration has remained hidden for two reasons: (1) the spiral ganglion cells, the cochlear neural elements commonly assessed in studies of SNHL, survive for years despite loss of synaptic connection with hair cells, and (2) the degeneration is selective for cochlear-nerve fibers with high thresholds. Although not required for threshold detection in quiet (e.g., threshold audiometry, auditory brainstem response threshold), these high-threshold fibers are critical for hearing in noisy environments. Our research suggests that (1) primary neural degeneration is an important contributor to the perceptual handicap in SNHL, and (2) noise exposure guidelines should be re-evaluated, as they are based on the faulty premise that threshold audiograms are the most sensitive measures of noise damage.
Development of high intensity focused ultrasound transducers to deliver specified shock wave amplitudes at the focus
Authors: Khokhlova Vera A. , Yuldashev Petr V. , Rosnitskiy Pavel B. , Maxwell Adam D. , Kreider Wayne , Sapozhnikov Oleg A.
Published: May 2014

High intensity focused ultrasound (HIFU) is currently emerging into many clinical applications. Certain HIFU modalities, histotripsy, for example, rely on the formation of high amplitude shocks in the focal waveform of the beam. These shocks develop at different focal pressure levels depending on the geometry of the HIFU transducer. The goal here was to determine optimal transducer parameters that would result in specified shock amplitudes and corresponding peak negative focal pressures. The hypothesis was that pressure level for shocks to form is mainly determined by the F-number of the transducer. As nonlinear effects accumulate almost entirely in the focal lobe of HIFU beams, shocks will form at the higher pressures for lower F-number transducers with shorter focal lobe and thus will have higher amplitudes. Simulations based on the Khokhlov-Zabolotskaya-Kuznetsov equation have shown that for typical HIFU transducers with 1–3MHz frequencies, geometries with F-number close to 1 are optimal for generating waveforms with about 70 MPa shocks and 12 MPa peak negative pressures. For lower F-number transducers, higher amplitude shocks and peak negative pressures will be formed unless cavitation occurs proximal to the focus to attenuate the focal beam. [Work supported by the grants MK-5895.2013.2, RFBR-13-02-0018, NIH-EB007643, and T32-DK007779.]
Enhancement of a general solution to Lighthill-Westervelt nonlinear acoustic equation to the cases of inhomogeneous and random media
Authors: Woodsum Harvey C.
Published: May 2014

A general solution to the Lighthill-Westervelt equation of nonlinear acoustics, previously developed and successfully applied to model the scattering of sound by sound and to the parametric array, has been generalized further for use in the cases of inhomogeneous and random media. The form of the solution makes use of an exact inverse differential operator in combination with a sequence of perturbation terms that comprise the multiple orders of nonlinear acoustic scattering to arbitrary order. Integration techniques have been developed which allow accurate, approximate, analytical solutions under particular circumstances. These solutions are shown to reduce to other previously known solutions in the appropriate limits.
Vibrational assessment of wood, composite, and plastic hurleys
Authors: Russell Daniel A.
Published: May 2014

The Gaelic sport of hurling combines elements of field and ice hockey, lacrosse, and even baseball. The hurling stick, or hurley, has a long narrow handle which tapers to a large flat paddle, or bas, and is primarily made from white ash. Sticks show variation in the thickness, size, and shape of the paddle and composite hurleys have recently been introduced to the game. In this paper, we use experimental modal analysis to study the vibrational mode shapes and frequencies of several ash and composite hurleys, in adult and youth sizes, including the infamous 1970's Wavin plastic hurley which was quickly abandoned due to excessive vibration and sting. Bending and torsional mode shapes are found to be similar to those in baseball bats and field hockey sticks. A third family of vibrational modes exhibiting bending in the handle and torsion in the paddle are similar to vibrational modes observed in ice and field hockey sticks. These three types of mode shapes help define the sweet spot as well as influencing the perception of feel in the hands of a player.
Relating moms Apostrophe productions of infant directed speech with their babies Apostrophe ability to discriminate speech: A brain measure study with monolingual and bilingual infants
Authors: Garcia-Sierra Adrian , Ramirez-Esparza Nairan , Fish Melanie S. , Kuhl Patricia K.
Published: May 2014

We report the benefit of Infant Directed Speech (IDS) on speech discrimination in 11- and 14 month-old monolingual (N = 16) and bilingual infants (N = 14). Mothers were instructed to read a booklet to their infants that contained sentences with target words (e.g., park, tear, bark, deer, etc.) at least once a day for four days. This activity was recorded by the LENA digital recorder that the infants were carrying around as they went about their lives. IDS was defined as the mothers' voice-onset time (VOT) durations when reading the booklet at home to their infants. Adult Directed Speech Mothers' IDS productions were correlated with their infants' brain responses associated with speech discrimination (Mismatch Negativity Response or MMR). The results showed that mothers' IDS correlated positively with the bilingual infants' positive-MMR and the monolingual infants' negative-MMR. Bilinguals' positive-MMR is interpreted as a less mature brain response since the positivity declines with age and a negative-MMR (adult-like) emerges later in development. These results show that even though the monolinguals and the bilinguals are at different developmental stages—as demonstrated by their MMRs— both monolingual and bilingual infants benefit from IDS to learn the sounds of their native language(s).
Acoustical Society of America Helmholtz-Rayleigh Interdisciplinary Silver Medal in Physical Acoustics and Biomedical Acoustics 2014: Mark F. Hamilton
Authors: Blackstock David T. , Crum Lawrence A. , Elko Gary W.
Published: May 2014

The Silver Medal is presented to individuals, without age limitation, for contributions to the advancement of science, engineering, or human welfare through the application of acoustic principles, or through research accomplishment in acoustics.
Acoustics design associated with natural ventilation
Authors: Chiang Weihwa , Wu Huiping , Hsu Haohsiang
Published: May 2014

Increased effort on building sustainability has caused a revolution in building acoustic design regarding savings in resources and energy. Sustainable design strategies such as natural ventilation, on the other hand, challenged the common practice in acoustic design. Case studies on building acoustic solutions associated with natural ventilation have been conducted and reviewed with multi-facet design concerns. Issues addressed included noise insulation of building facade that allows natural ventilation, abatement of noise from urban sub-stations that generated heat, replacing mechanical ventilation system by stack ventilation for parking garages to decrease both power consumption and mechanical noise, and noise suppression of ceiling fan to prevent from overuse of PA system in classrooms that may consequently cause further problems. Discussions were also made about degradation of absorbent materials caused by increased humidity due to natural ventilation.
Top opportunities and challenges in meeting acoustics criteria in green buildings—Specific case studies
Authors: Bridger Joseph F.
Published: May 2014

Acoustics criteria found in for example LEED, DODEA, and ANSI S12.60 (classroom acoustics in schools) often must be met either in addition to or as part of the sustainable design project requirements. The challenge is that building designs are changing to meet the goals of sustainable design, often with unanticipated effects on building acoustics. The criteria themselves are evolving as experience is gained. Acoustics materials are also adapting to meet sustainable design goals. We will discuss the top opportunities and challenges we are finding in meeting acoustics criteria in green buildings.
Leadership in energy and environmental design acoustics compliance: Simulation versus field measurements
Authors: Tsaih Lucky S. , Huang Lee-Su , Huang Lisa
Published: May 2014

In classrooms, acoustics and lighting are equally critical qualities that shape the learning environment. LEED IEQ Prerequisite 3: Minimum Acoustic Performance only addresses a prescriptive requirement for compliance. LEED IEQ Credit 8.1: Daylight and Views allows several options for demonstrating achievement of minimum illumination levels: simulation, prescriptive, measurement, and combination. In examining PK Yonge Elementary School in Gainesville, Florida, field measurements of daylighting and acoustics were performed. Measurements demonstrate that 3 pm illumination levels are better than at 9 am, but model simulations show both to be the same. Model simulation results are at least 10 times better than field measurements. This discrepancy suggests that measurements are critical for more accurate results. Acoustical model simulations for reverberation time were also conducted and the results showed inconsistencies from field measurements. Both daylighting and acoustical simulations provide preliminary results but a range of unpredictable factors affect the final precision of the simulation results. These factors include as-built material finishes, furniture layouts, reflectance, and absorption coefficients. Therefore, LEED should require that upon a building’s completion, sample acoustic field measurements are necessary to verify compliance.
Trends and variations in the baseline soundscape of America’s first offshore wind farm
Authors: Mooney T Aran , Kaplan Maxwell B. , Izzi Annamaria , Sayigh Laela
Published: May 2014

With the development of Cape Wind, Nantucket Sound, Massachusetts may become home to America’s first offshore wind farm. The goal of this ongoing project is to establish the baseline (pre-construction) soundscape of anthropogenic and biological activity, including diel and seasonal variability of various sound types, at the construction site and nearby comparison sites. Acoustic recorders have been deployed since April 2012, recording on a 10% duty cycle (sample rate: 80 kHz). Multiple fish sounds have been identified with the predominant signals attributed to cusk eels (Family Ophidiidae). Cusk eel sounds consist of a series of pulses, with energy between 400 and 2500 Hz. They are detectable from April to October, with dense choruses occurring during the summer months. Sound energy levels during these choruses increased near the hours of sunrise and sunset. Vessel traffic also showed diel and seasonal trends, with peaks during the daytime and in the summer. These trends in biological and human activity provide key baseline records for evaluating the possible influence of wind farm construction and operation on a local US soundscape.
Single-sensor, cue-counting density estimation of highly broadband marine mammal calls
Authors: Küsel Elizabeth T. , Siderius Martin , Mellinger David K.
Published: May 2014

Odontocete echolocation clicks have been used as a preferred cue for density estimation studies from single-sensor data sets, studies that require estimating detection probability as a function of range. Many such clicks can be very broadband in nature, with 10-dB bandwidths of 20 to 40 kHz or more. Because detection distances are not realizable from single-sensor data, the detection probability is estimated in a Monte Carlo simulation using the sonar equation along with transmission loss calculations to estimate the received signal-to-noise ratio of tens of thousands of click realizations. Continuous-wave (CW) analysis, that is, single-frequency analysis, is inherent to basic forms of the passive sonar equation. Considering transmission loss by using CW analysis with the click’s center frequency while disregarding its bandwidth has recently been shown to introduce bias to detection probabilities and hence to population estimates. In this study, false killer whale (Pseudorca crassidens) clicks recorded off the Kona coast of Hawai’i are used to quantify the bias in sonar equation density estimates caused by the center-frequency approach. A different approach to analyze data sets with highly broadband calls and to correctly model such signals is also presented and evaluated. [Work supported by ONR.]