bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysing the effect of non-acoustical parameters on physiological response due to traffic noise exposure
Authors: Manohare Manish , Elangovan Rajasekar , Oberman TIn , Aletta Francesco , Kang Jian , Parida Manoranjan
Published: November 2023

Traffic noise, as an environmental stressor, impacts both auditory and non-auditory human health through a combination of acoustical and non-acoustical parameters. This study investigates the effects of sex, noise sensitivity, and cross-cultural differences on physiological stress responses to traffic noise exposure. A psychophysiological listening experiment was conducted with 60 participants from the United Kingdom and India to analyze the variation in physiological responses to the noise stimuli. The findings reveal significant gender differences in psychophysiological responses, with females exhibiting higher physiological arousal and potentially experiencing greater stress levels at moderate loudness levels compared to males. Moreover, individuals with high noise sensitivity displayed heightened stress levels and physiological arousal. Additionally, British participants exhibited higher physiological arousal, as indicated by increased skin conductance response parameters, compared to the Indian group. This suggests that exposure to Indian traffic noise, characterized by louder sounds and increased honking, leads to heightened stress levels among British participants. In conclusion, these findings contribute to our understanding of the relationship between traffic noise and physiological outcomes, shedding light on the influence of non-acoustical parameters. It also underscore the potential health implications of chronic noise exposure on human health.
Improving intelligibility of dysarthric speech in noise for listeners with hearing loss
Authors: Yoho Leopold Sarah , Borrie Stephanie , Barrett Tyson , Healy Eric
Published: November 2023

Noise reduction strategies based on time-frequency masking have been shown to provide substantial improvements in the intelligibility of speech in noise for both listeners with normal and impaired hearing. Previous studies on this type of noise reduction have involved intact, well-articulated speech spoken by healthy talkers (i.e., not disordered speech). However, the prevalence of speech disorders such as dysarthria is substantial, particularly in the aging population, which is highly susceptible to the impacts of hearing loss. We recently demonstrated the considerable impact of background noise on dysarthric speech as well as the effectiveness of time-frequency masking to improve the intelligibility of this disordered speech in noise for listeners with normal hearing (Borrie et al., 2023). Here, we present data on the feasibility of time-frequency masking to increase the intelligibility of dysarthric speech for listeners with sensorineural hearing impairment. Preliminary results indicate that the Ideal Quantized Mask, a method of time-frequency masking, significantly improves percent words correct scores of dysarthric speech in noise for listeners with hearing loss. Results will be discussed in relation to the specific impact of background noise on dysarthric speech, and the relationship between sensorineural hearing loss and dysarthric speech.
Speech-in-competition auditory assessment and the influence of the bilingual experience
Authors: Bustos Katia P. , Vivanco Rodolfo S. , J. Gallun Frederick , R. Seitz Aaron , Lelo de Larrea Mancera Esteban Sebastian
Published: November 2023

The measurement of audition has historically focused on the detection of pure tones; however, it has been proposed that a thorough evaluation should include measures of language reception in competition. The auditory challenge in the real world occurs mostly in competitive environments that require further auditory processing, and not only rely on peripheral, but also higher-order processes. Nevertheless, innovation of speech in competition assessments has occurred primarily in English and few tools have been translated, validated, and investigated in Spanish. Likewise, the bilingual experience of subjects whose native language is not English has not been sufficiently considered when using speech audiometry in hearing evaluation, casting doubt on assessment validity. In this study, we collected repeated measures of the digits-in-noise and the spatial release from masking tasks in English and Spanish-languages on a sample of fifty-six healthy Mexican subjects with varying degrees of English experience. We found significant differences across two sessions in the spatial release from masking, but not the digits-in-noise test. Additionally, we observed that a participant's bilingual experiences, but not cognitive ability, were predictive of language-related differences in performance. We finish by discussing bilingual requisites for valid and reliable speech-in-competition assessment in linguistically diverse individuals.
The effects of hearing loss and envelope processing on speech understanding in adverse acoustics during childhood
Authors: Easwar Viji , Peng Z. Ellen , Boothalingam Sriram , Seeto Mark
Published: November 2023

Children with hearing loss (CHL) experience greater difficulty understanding speech in the presence of noise and reverberation relative to their normal hearing (CNH) peers despite provision of appropriate amplification. The fundamental frequency of voice (f0)—a salient temporal cuei—could play a significant role. However, the nature of deficits and its relationship with speech understanding are poorly understood. To this end, we evaluate the role of f0 encoding on speech perception abilities of CNH and CHL in the presence of noise and/or reverberation. In 14 CHL and 29 CNH, envelope following responses (EFRs) were elicited by vowels, modified to estimate f0 encoding in low (<1 kHz) and higher frequencies. Both groups demonstrated a frequency-dependent dichotomy in the disruption of f0 encoding– greater disruption at low frequencies due to noise and greater disruption at the high frequencies due to reverberation. In contrast to CNH, CHL demonstrated: (a) greater disruption of f0 encoding at low frequencies, particularly in the presence of reverberation, (b) a positive relationship between f0 encoding at low frequencies and speech discrimination. Together, these results provide evidence for the persistence of suprathreshold temporal processing deficits in children despite the provision of appropriate amplification to compensate for hearing loss.
The intonation of Wh-questions in two Basque varieties
Authors: Delgado Fernandez Nerea
Published: November 2023

This presentation examines the intonation of Wh-questions in two under-investigated varieties of Basque: North-central Gipuzkoan (Spain) and Labourdin (France). A total of 288 sentences elicited through a semi-spontaneous task were analyzed in Praat (Boersma and Weenek, 2018). As acoustic cues, we center on final tonal movements and lengthening, two aspects for which there is limited to no information for the varieties under study. Results for final contours in Gipuzkoa showed that 58.2% of sentences were produced with rising intonation (L* H% begin the most predominant contour), while the falling contour attested in other Basque varieties (L* L%) appeared in only 41.8% of cases. In Labourdin Basque, 77.3% of sentences were produced with a rising (L* H% also being the most prevalent configuration). Speakers, however, tended to produce risings of mid height. Regarding lengthening, this cue was more relevant in Gipuzkoan Basque. We will connect these novel findings to the intonational characteristics described in prior studies (Elordieta, 2003; Elordieta and Hualde, 2014; Duguine and Irurtzun, 2020). Moreover, since Basque in these territories is in contact with Spanish and French, a brief comparison across languages will also be included. This will be the first attempt at such a comparison.
A sociophoentic study of intergenerational differences in Kemie language
Authors: Liu Xirui
Published: November 2023

Previous sociophonetic studies have primarily concentrated on European languages or other dominant languages, with Chinese dialects and minority languages receiving less attention. This article aims to examine the phonetic variations of vowels, stops and tones emerged owing to age differences in Kemie Language, an Austroasiatic language in China. 18 speakers were categorized by age into young, middle-aged and older groups with 6 speakers in each group. Acoustic parameters such as formants, VOT, f0 and duration were extracted, and linear mixed effects model and repeated measures ANOVA in R were employed to test whether the above parameters were significantly different across the groups. Results show that: (1) The monophthongs /ɛ/ /a/ /ɔ/ manifest significant variations through tongue height or frontness or both. (2) VOT values of /b/ in the above three groups are significantly different and inverse with age, while no consistent conclusions can be reached in terms of /d/ /ɡ/. (3) Low-rising (13) and high-rising (35) tones with stop codas (cu yun wei) haven’t merged across the groups, but pitch range of the two tones become narrower with decreasing age; Low-rising (13) and mid-level (33) tones with sonorant codas (shu yun wei) have merged across groups.
Analysis of the sound field in circular spaces using small scale models and parallel phase-shift interferometry
Authors: Imanishi Mayuko , Nozawa Haruka , Suzuki Nanase , Oikawa Yasuhiro
Published: November 2023

In acoustic design, the use of circular spaces is generally avoided. This is because these spaces present several acoustic problems, for example, “whispering gallery,” and low diffusivity of sound. These room acoustic problems have generally been dealt with by installing diffusers on walls. In this study, we designed the acoustics of the circular space by applying diffusers based on primitive roots and analyze the sound field. These diffusers were proposed by Schroeder and take advantage of the randomness of the numerical sequence generated from primitive roots. We designed several small circular models attached the diffusers and printed them with a 3D printer. The sound field in the models were measured and visualized using parallel phase-shifting interferometry, one of the optical sound measurement methods. As a result, “whispering gallery” phenomenon was improved, and focal points were less likely to occur by the application of diffusers based on primitive roots.
Perception of social vocalizations in bats
Authors: Bohn Kirsten M. , Smotherman Michael
Published: November 2023

Although bats are well known for their highly specialized echolocation systems, the majority of produce social vocalizations whose form, function, and complexity vary widely across taxa. Here we review and compare two types of social vocalizations bats produce and perceive: infant isolation calls and complex songs. Infant isolation calls are simple (2 notes), innate vocalizations produced by the majority of mammals with little specialization in bats. Research has shown that auditory sensitivity co-evolved with isolation call frequencies across bats and bats can discriminate among individuals using isolation calls. In contrast to isolation calls, Tadarida brasiliensis songs are much more complex (100’s of notes), hierarchically structured and highly variable across renditions. Playbacks revealed that bats rapidly perceive echolocation from passing conspecifics and sing in response. This occurs only in response to echolocation, even though “echolocation” calls are embedded within complex song phrases. Thus, bats can rapidly discriminate between “echolocation alone” and “song with echolocation embedded” signals. We further share some evidence of differences in the syntax of songs produced in response to songs from familiar and unfamiliar bats. These studies and new discoveries of bats’ songs will no doubt have a large impact on our understanding of vocal perception and cognition.
Attention modulates cortical, but not subcortical responses
Authors: Figarola Victoria , Noyce Abigail , Tierney Adam , Maddox Ross , Dick Fred , Shinn-Cunningham Barbara
Published: November 2023

Organisms often need to attend to one signal within a crowded acoustic scene. While attentional effects in the auditory cortex are robust, what happens subcortically remains mysterious. We combined previous electroencephalography paradigms to measure whether attention modulates subcortical as well as cortical responses. Participants heard competing, temporally interleaved low and high melodies. Each melody had notes repeating at 2 Hz, with an overall note rate of 4 Hz. Participants attended to either the high- or low-pitched melody and responded whenever a 3-note pattern repeated in that stream. From past work, we expected to see strong cortical EEG responses at 2 Hz, but with a phase that shifted depending on which melody listeners attended. Importantly, we engineered the notes so that (1) low and high melodies excited different cochlear regions, and (2) each pitch period of each note elicited an auditory brainstem response (ABR). This allowed us to test whether attention altered responses along the ascending pathway in the brainstem. We found phase shifts in cortical responses with shifts of attention. While we found robust ABRs, we saw no evidence that attention modulated any of the ABR components. These results suggest that attentional effects in subcortical structures are weak, at best.
Sensing in the swarm: Spectro-temporal variation may facilitate self-recognition of echoes for bats flying in dense groups
Authors: Blackstock Stephen , Stevenson Robert , Vanderelst Dieter , Haberman Michael , Domski Paul , Kloepper Laura
Published: November 2023

Most biosonar models predict that bats rely on the correct assignment of an echo from a broadcast signal to successfully perceive their environment, which should be difficult for bats in dense groups. Brazilian free-tailed bats (Tadarida brasiliensis) form some of the largest aggregations on the planet and have flexible characteristics of their echolocation signals. We hypothesize they use subtle variations in spectro-temporal characteristics to facilitate echolocation in dense groups. To record from inside the swarm, we used both a stationary microphone that opportunistically captured the passing bat swarm, and a custom video and acoustic recorder carried by a trained hawk that flew through the swarm. We computed spectrograms from the acoustic recordings and extracted “time-frequency ridges.” These ridges were fit to low-order polynomials to generate model frequency modulation functions, which in turn uniquely determine continuous time-series representations of modeled emission waveforms. Standard signal detection methods (cross correlation and background normalization) enabled quantitative estimation of detection performance, including rejection of interfering emissions and echoes. Our results demonstrate that subtle but specific variation in spectro-temporal shape can constitute the basis of call differentiation, which may be an adaptive strategy used to reject acoustic signals from conspecifics when echolocating in dense swarms.
Making underwater noise predictions using frequency response functions generated by the Operation Round Trip method
Authors: Tranter Scott , Glachan Robbie , Potter Robert
Published: November 2023

The Round Trip method was derived as a means to acquire frequency response functions at passive locations, where the term ‘passive’ specifies that no external known force has been applied. This allows frequency response functions to be generated at locations where the degree of freedom cannot be excited by conventional means. Sound and vibration produced by operational sources can increase signal-to-noise ratios in large complex systems and improve the quality of the measured frequency response functions, where it can be challenging to effectively excite the system by conventional experimental means. In this study, the application of a modified version of the Round Trip method that is based on transmissibility functions, termed the Operational Round Trip method, has been investigated to determine whether the forces generated by an operational source, such as an offshore wind turbine, could be utilized to predict the frequency response functions at and between passive measurement positions within a coupled mechano-acoustical system. These predicted frequency response functions have been used with the blocked forces of a vibratory source to make underwater noise predictions at remote positions, which were validated against measured underwater noise measurements.
Spatiotemporal modulations in acoustics: From nonreciprocity to mechanical computing
Authors: Moghaddaszadeh Mohammadreza , Mousa Mohamed , Adlakha Revant , Attarzadeh Mohamed Ali , Aref Amjad , Nouh Mostafa
Published: November 2023

Spatially graded materials have been a cornerstone of acoustic metamaterials for decades, enabling wave manipulation across different length scales. Likewise, structures with time-varying material properties have gained traction in wave filtering applications. Put together, systems exhibiting concurrent spatial and temporal modulations of one or more parameters (e.g., stiffness or phase) can unlock an array of new features ranging from nonreciprocal propagation to frequency-dependent wave beaming. In this talk, we will introduce the notion of dynamic phase gradients, i.e., a spatial phase shift between neighboring elements (of a metasurface) or transducers (of a phased array) which also varies in time. Through theory and experiments, we will demonstrate that the resultant systems are capable of (a) generating multiple scattered harmonics of a single input which simultaneously propagate in different directional lanes, each carrying a unique frequency footprint, and (b) exhibiting non-identical beaming patterns in transmission and reception by breaking time invariance. We will present an application of this concept in the development of a mechanical neural network via reconfigurable elastic metasurfaces, designed to perform a computational task. Since the frequency channels of a spatiotemporally-modulated metasurface are independently tunable, they can be assigned distinct tasks, thus allowing parallel operations in mechanical computing systems.
Acoustic scattering from spatiotemporally modulated domains
Authors: Goldsberry Benjamin M. , Wallen Samuel P. , Haberman Michael
Published: November 2023

Acoustic and elastic metamaterials with space- and time-dependent material properties have received significant attention recently as a means to realize systems that induce nonreciprocal wave propagation in the bulk or enable frequency and mode conversion of fields scattered from metasurfaces. A previous study derived a nonreciprocal Green’s function for flexural waves in a one- and two-dimensional finite plate with a spatiotemporal modulation of the Young’s modulus [Goldsberry et al., J. Acoust. Soc. Am. 150(4), 2021]. In this work, we generalize the nonreciprocal Green’s function approach to the acoustic case of scattering from an inhomogeneity whose properties are general functions of space and time. Canonical geometries where the analytical solution is known for the unmodulated case will be investigated. Computations of the scattered field directivity pattern will then be carried out as a function of the modulation parameters to determine cases that yield a large degree of control over the scattered field directivity pattern for each generated frequency harmonic. [Work supported by ONR.]
Interesting effects of harmonically scattered waves from 1D functionally graded nonlinear inclusions
Authors: Ghodake Pravinkumar
Published: November 2023

The interaction of monochromatic elastic waves with nonlinear inclusions shows the presence of harmonically scattered waves. Challenges in obtaining theoretical solutions and limitations of conducting experiments to understand harmonic scattering of the nonlinear waves from functionally graded materials motivate us to conduct numerical experiments. Harmonic scattering of the elastic waves from highly local functionally graded nonlinear inclusions is exploited in this study to propose a novel building block of new nonlinear metamaterials that can effectively control harmonic responses. The simple, commonly observed, unique spatial distribution of the nonlinear parameters is proposed so that the area under the distribution remains the same for a constant-sized inclusion. Despite different spatial distributions, these functionally graded distributions show the same harmonic responses of both forward and backscattered waves during the interaction of monochromatic waves and one-way two-wave mixing. The amplitudes of all possible combinations of harmonics remain the same as long as the area under the spatially distributed nonlinear parameters curve, irrespective of the distribution curves. Reducing the area under the curve of the functionally graded nonlinear inclusion simply by reducing the maximum value of the functionally distributed nonlinear parameters, a decrease in the amplitudes of the harmonics is demonstrated.
Investigating vibration-based methods of measuring impact noise insulation to improve reproducibility at low frequencies
Authors: Girdhar Sunit , Shafer Benjamin M. , Dong Wayland , LoVerde John
Published: November 2023

Standard impact noise insulation testing is based on measuring the average sound level in a reverberant field in order to estimate the incident and/or radiated sound power. While this method is straightforward, the variation under reproducibility conditions is significant, and a significant portion of the uncertainty is due to the complications of measuring the sound field in the receiving space. This variation is largest at low frequencies, where the effects of spatial variation and modes in the receiving room are well documented. Measuring the vibration on the surfaces of an assembly, or measuring the vibration propagation through an assembly, may provide another measure of the impact insulation of the assembly that is not affected by the sources of uncertainty associated with measuring the sound field in a room. This paper reports on the results of preliminary investigations on floor assemblies in situ while excited by impact sources and the comparison with conventional receiving room sound pressure measurements.
Analysis of the impact of low-frequency traffic noise in two South American cities
Authors: Montano Walter , Gonzalez Alice E. , Gushiken Elena I.
Published: November 2023

Traffic noise is one of the most important sources of annoyance in South American cities. The obsolescence of vehicles and the lack of controls are two of the main causes of this noisy traffic. Since the legislation considers it as a typical source of urban noise, the metric to analyze traffic noise is the A-weighted dB (so-called dBA); therefore, it is not easy to analyze its real impact on human health because low-frequency sound levels are strongly reduced by A-weighting. This article presents the results of a field study carried out in Lima (Peru) and Montevideo (Uruguay) to analyze the impact of traffic noise focused the lowest frequencies, in the range defined by ISO (1/3 octave bands between 16 and 200 Hz), and the WHO recommendation using the whole audible frequencies. The data for Lima were taken in places where a specific acoustic EIS has been required, while the Montevideo´s one were for its noise map. The spectra were processed looking for a representative low-frequency traffic noise metric, so the values of (C–A) obtained byWHO recommendation and ISO recommendation are compared. The expected impact on human health is much more worrisome when low-frequencyrange are explicitly considered.
Modernization of the instrumentation requirements to support ISO noise test standards
Authors: Schmitt Jeff G. , Hook Joseph , Schaffer Michael
Published: November 2023

ISO TC43/SC1/WG28 develops the basic machinery noise test standards for products and equipment. This includes the determination of sound power levels in the ISO 3740 series and the measurement of operator/bystander sound pressure levels in the ISO 11200 series. The instrumentation requirements for these standards have historically been based on a reference the sound level meter standard, IEC 61672, supplemented by another to IEC 61260 for fractional octave filters. Both IEC standards are fundamentally based on the concept of the measurement system being a packaged sound level meter. Many modern implementations of these standards no longer use a sound level meter. Many now use multi-channel, computerized instrumentation systems and custom software. These systems provide measurement equivalence to the IEC sound level measurement standards. However, they don’t fully comply with all of the requirements in these IEC standards. Many acoustic testing programs have chosen to ignore these non-complianceissues, have implemented systems that are more efficient, lower measurement uncertainty and provide measurement equivalence to IEC 61672 and IEC 61260. As industry has already decided to implement these systems, there is a need to develop modernized instrumentation requirements to support the basic sound power and sound pressure level measurement standards using current technology.
The relationship between freight and passenger train noise levels and distance on the Sydney Metropolitan Rail Network across 281 measurement sites
Authors: Weber Conrad , Schulten Christopher
Published: November 2023

Transport for NSW undertakes noise monitoring at a range of distances and locations around the NSW Government-managed rail network. The monitoring quantifies noise levels from freight and passenger train operations and informs delivery of noise reduction programs including the Transport for NSW’s Freight Noise Attenuation Program, which was launched in 2015. Comprehensive noise monitoring over a typical period of two weeks has been undertaken at 281 representative locations adjacent the passenger and freight rail network around Sydney. Results were analyzed to determine the LAE noise levels from each freight and passenger train passby, and the average weekday LAeq(15hour) daytime and LAeq(9hour) night-time levels. Curves of best fit are presented that illustrate the relationship between freight and passenger train noise levels and the distance to the near track. These curves of best fit can be utilised by Government agencies and acoustic practitioners to quantify the potential noise impact of freight and passenger train operations at a range of distances and locations close to the NSW Government-managed rail network and identify appropriate noise mitigation measures.
New road surface noise corrections for New Zealand
Authors: Jackett Richard , Bull John , Chiles Stephen , Wareing Rob , Bell George
Published: November 2023

New Zealand’s transport agency has developed a close-proximity (CPX) noise trailer and primarily operates it as a road surface research tool. Early CPX survey data revealed very high longitudinal variability in the performance of porous asphalts on the highway network (±5 dB). Further study and optimization of porous asphalt mixes has resulted in high-performance low-noise surfaces that are reliably 5 dB quieter than standard NZ porous asphalt. The new surfaces and improved surface data inspired a recalibration of NZ’s implementation of the CRTN road-traffic noise model, for which a novel method based on CPX survey data and individual vehicle pass-by measurements was employed. The relationship between CPX and wayside levels was more complex than anticipated; CPX measurements did not capture all the surface attributes/interactions contributing to the wayside level (such as porosity, directivity). The methodology proved successful and a new table of surface corrections has been published, embodying the recalibration of CRTN for NZ in 2023. CRTN predictions using the new corrections have performed well when evaluated against independent road-traffic noise monitoring data from NZ highways.
Recent progress on nonlinear ultrasonic phased array for closed-crack imaging
Authors: Ohara Yoshikazu
Published: November 2023

Closed cracks are challenging defects for ultrasonic testing since they are transparent to conventional ultrasound techniques. This can cause the underestimation or overlook of closed cracks, resulting in potential catastrophic accidents. To solve this problem, several types of nonlinear ultrasonic phased array has been developed by combining nonlinear ultrasonics with phased array (PA). In this study, we introduce the recent progress on nonlinear ultrasonic PA. The first one is called fundamental wave amplitude difference (FAD), which is based on the nonlinear incident-wave-amplitude dependence of fundamental responses. The key to the success of FAD is how high incident wave amplitude can be generated in samples to cause the contact vibration of crack faces. However, increasing the incident wave amplitude at MHz frequencies is not easy. To enhance the applicability of nonlinear ultrasonic PA, we have also developed ultrafast imaging (MHz range) with pump excitation (kHz range). We have successfully captured high-speed crack dynamics using plane wave imaging (PWI) during the pump excitation that can generate a large displacement of more than 1000 nm. Furthermore, we will talk about ongoing work toward 3D crack imaging. [Work partially supported by JSPS KAKENHI (19K21910, 21H04592, 22K18745) and JST FOREST program (JPMJFR2023).]
Signal processing and acoustic calibration method of millimeter-wave vibration sensor
Authors: Kuroda Jun , Matsue Yuudai , Kashima Yuu , Oikawa Yasuhiro , Nozawa Haruka
Published: November 2023

Millimeter-wave sensors can be utilized as non-contact vibration sensors. Applications of millimeter-wave vibration sensors are the vital sensing of humans (heartbeat, respiration, body motion), factory machines, and vibration sensing of social infrastructures, such as buildings and bridges. Millimeter-wave vibration sensors can simultaneously detect the position and the waveforms of the vibration displacements of vibration objects. The primary signal processing of millimeter-wave sensors is two-dimensional fast Fourier transform (2D-FFT), detecting the arrival direction (DOA) and processing the micro-Doppler signals. The detectable areas of the millimeter-wave vibration sensors are defined using the parameters related to these three signal-processing blocks. Measured vibration waveforms by millimeter-wave vibration sensors include all components of the vibration displacements in the defined detectable area. Therefore, the waveform of the vibration displacement is influenced by the definition of the detectable area and the vibration form of the vibrating object. The measured values of millimeter-wave vibration sensors must be calibrated with attention to these influences. The vibration waveforms of vibrating objects are estimated by acoustic measuring methods, such as the laser Doppler vibrometer and the parallel-phase shifting interferometry. This paper describes calibration methods of millimeter-wave vibration sensors employing these two measuring methods.
A review of structure-borne noise from elevated rail structures
Authors: Larner David , Brown Graham , McGuckin Damian
Published: November 2023

In the general case, noise from elevated rail systems consists of direct and reverberant airborne noise radiated from wheels and rails, noise from on-train sources, aerodynamic noise, and structure-borne noise reradiated from the viaduct or bridge structure. This paper presents a method of predicting structure-borne noise radiating from viaducts due to rail operations. The structure-borne noise is calculated by first determining the dynamic force input to the elevated structure at the rail attachment points due to excitation from wheel-rail roughness. Vibration transfer between structural elements, such as parapets and structural webs is estimated using Statistical Energy Analysis (SEA), which is also used to calculate the sound power radiating from the structure. The prediction of receiver sound pressure levels is carried out using simple noise propagation models that account for the geometric relationships between structural elements and receiver locations.
Comparing user human comfort vibration on key commuter cycling routes in Melbourne Australia
Authors: Ritchie Simon , Evenden Craig
Published: November 2023

Cycling as an active mode of travel is recognised as an important part of the transport mix within Melbourne Australia. This city has a number of identified key commuter cycling routes in the vicinity of the CBD. Human comfort, including vibration level, is a factor in the selection of routes by an end user. This study aims to quantify the measured vibration experienced by a cyclist on a set of these main cycling routes informed by ISO2631-1 methods. Overall vibration values are then compared between routes. The results are combined with GPS position and speed data to enable mapping and visual route comparison.
Articulatory and acoustic characteristics of occlusivized sonorants in Shakou Hakka
Authors: Havenhill Jonathan , Liu Ming , Sevilla Robert Marcelo , Perry J. J. , Thompson Arthur Lewis
Published: November 2023

This study examines a pattern of sonorant occlusivization in a dialect of Hakka Chinese spoken in Shakou Township, Guangdong, China. This variety exhibits variable occlusivization of /l/ (realized as centralized [ld ∼ ld ∼ d]) and denasalization of initial /m, ŋ/ (realized as prenasalized stops [?b, ?g]). Mid-sagittal and coronal ultrasound with synchronized audio, EGG, and nasalance recordings were collected from one speaker, along with acoustic recordings from 5 speakers. Partial occlusivization of /l/ occurred in 74.8% of words with high /i, y, u/ but does not occur in words containing low or mid vowels. Occlusivization of /l/ has an average duration of 42ms and is characterized by a significant decrease in mid-frequency acoustic energy (−6 dB, p < 0.001). Ultrasound data reveal tongue body raising and parasagittal contact during occlusivization, indicative of overlap between the tongue gestures required for /l/ (with lateral airflow) vs. /i, y, u/ (with lateral bracing). Denasalization, which has a similar mean duration of 39.5ms, occurs in 42.9% of words containing non-high vowels and 86.25% of words containing high vowels. Although these patterns differ with regard to their phonological conditioning, gestural interaction during sonorant-vowel sequences may provide a common underlying mechanism for both processes.
The use of professional audio external USB sound cards for building acoustics measurements
Authors: Davy John L.
Published: November 2023

CSIRO purchased an open application programming interface for hardware with an ethernet connection from a major acoustical instrument manufacturer. Using this interface, the author developed software for fractional octave band filtering with linear and exponential averaging. He then extended this software to automatically measure reverberation time. Fast Fourier Transform and Stepped Sine software was also developed. He then realized that CSIRO also owned two professional audio external USB sound cards. One of these had eight analogue inputs and ten analogue outputs. The other had two analogue inputs and two analogue outputs. Both could supply 48 V phantom power on their analogue inputs. It is possible to purchase phantom power preamplifiers for professional measurement microphones, but CSIRO decided to purchase phantom power to IEPE pre-amplifier adaptors. This enabled the use of professional pre-polarized microphones with IEPE microphone preamplifiers and accelerometers with built-in IEPE preamplifiers. CSIRO also had external USB hardware from another acoustical instrument manufacturer. Upon opening this instrument, it consisted of a professional audio external USB sound card and an IEPE front end for the two analogue input channels. The author decided to produce a version of his software that could be used with these three external USB sound cards.
BIM-based sound insulation performance evaluation of interior walls
Authors: Kwon Youngmin , Kim Changhyun , Kim Gyung
Published: November 2023

As a general contractor, acoustical design confirmation of a project at construction stage is rather limited especially if it is large-scale. Among others, many interior walls of the building projects are found to be improperly designed in terms of sound insulation in that chances are hardly given for the most projects to be intervened by an acoustic expert at their design stage. In many cases, they turn out to be either underperformed or overperformed. This study developed a tool for holistically evaluating sound insulation design of interior walls across the building areas. It was designed on the basis of BIM modeling to be fast-tracked in supporting either the architects or general contractors for a quick and broad design review. Mapping of the information of room use and wall types with their predicted or measured sound insulation data on to a BIM model is set out to compare to the design criteria according to room use and adjacency. The results are simulated on both 2-D and 3-D BIM models, visually presenting the sound insulation performance. A report is instantly generated on performance qualification with the information of wall types, surface areas, etc. It also suggests alternative wall types as necessary.
Measuring the sound of bubbles: Passive acoustic gas flux inversion
Authors: Roche Ben , Caudron Corentin , White Paul , Bull Jonathan
Published: November 2023

There is an ever growing need to be able to detect and quantify marine gas seeps, both natural and man-made. One potential avenue for achieving this is via passive acoustic flux inversion. Such techniques use the frequency of oscillation of newly released bubbles (the Minnaert frequency) to determine the size (radius) and number of bubbles released from a seep in a given time. Passive acoustic flux inversion offers a number of advantages over active acoustics, namely, being low cost and energy making them ideal for long term monitoring of known sites. Recent studies have demonstrated how passive acoustic inversion can provided fresh insight into the variability of natural seeps, with changes being correlated to tides, surface seiches, and even day/night temperature cycles. Furthermore, we are now applying this technique to monitor volcanic activity, correlating changing rates of gas release with increasing volcanic activity, developing a new eruption monitoring tool. This talk will introduce the theory behind passive acoustic gas flux inversion, detail case studies and future projects with an open invitation for collaboration.
Optical coherence elastography and Brillouin spectroscopy for tissue biomechanics
Authors: Larin Kirill
Published: November 2023

Quantifying the biomechanical properties of the different tissues can provide crucial information for disease detection and guiding precision therapeutic interventions. Optical coherence elastography (OCE) is an emerging technique to assess the mechanical properties of tissues completely noninvasively. Typically, elastography involves an external mechanical excitation of the tissue. We recently adopted the air-coupled acoustic radiation force method to generate elastic waves in tissues. This method shows several clear advantages other than the traditionally used air-puff excitation. Also, there is increased interest in passive elastography, where the mechanical response to natural physiological forces like heartbeat and respiration is measured. I will demonstrate the capability of OCE to measure tissue biomechanics in response to spatially varying fluctuations in IOP due to the heartbeat—thus, without any external force. Finally, I will demonstrate a few examples of the application of Brillouin spectroscopy to quantify tissue mechanical properties during Neural Tube Closure in mammalian embryos.
Flexion pulse wave in the retina: Toward à mechanical characterization of blood vessels?
Authors: Laloy-Borgna Gabrielle , Catheline Stefan , Puyo Léo , Nishino Hidero , Atlan Michael
Published: November 2023

The risk of cardiovascular events is linked to arterial elasticity that can be estimated from the pulse wave velocity. This symmetric wave velocity is related to the wall elasticity through the Moens–Korteweg equation. However, ultrasound imaging techniques need improved accuracy, and optical measurements on retinal arteries produce inconsistent results. After a quick historical review, it will be shown that the observation of an antisymmetric pulse wave, namely, the flexural pulse wave is possible. An optical system performs invivo wave velocity measurements on retinal arteries and veins. Velocity estimation ranges between 1 and 10 μm per second. The theory of guided waves confirms the existence of this wave mode and its low velocity. Natural flexural waves can also be detected at the bigger scale of a carotid artery using ultrafast ultrasound imaging. This second natural pulse wave has great potential of becoming a biomarker of blood vessel aging.
Ultrasonic testing for metal additive manufacturing: Experience with new course development
Authors: Turner Joseph A. , Sotelo Luz D. , Matz Nathanial
Published: November 2023

Metal additive manufacturing (AM) has brought about the need for nondestructive evaluation (NDE) methods to assess part quality. AM processes result in complex microstructures, porosity, material texture, and residual stresses all of which may vary spatially throughout the part. Thus, knowledge of ultrasonic NDE methods to characterize materials is relevant to the AM community. To address this challenge, a new graduate-level course entitled “Ultrasound for Metal Additive Manufacturing,” was created at the University of Nebraska-Lincoln. The course followed a cognitive-situative blended learning approach to give students practical ultrasonics training regardless of prior acoustics background. The theory introduced key topics including: the general wave equation, plane wave solutions, waves in isotropic solids, impact of material anisotropy, role of material interfaces, reflection and transmission, surface waves, scattering, dispersion, material dissipation, and scattering attenuation. A series of laboratory experiments allowed students to learn: experimental setups, signal processing, transducer properties and selection, beam mapping, wave speed and attenuation measurements, and diffuse-field measurements. Finally, each student developed a project incorporating ultrasound measurements into their individual AM research. Their findings were included in research articles, conference presentations, and PhD dissertations. This presentation will describe the course design, successes, and recommendations for future implementations.
New reference day atmosphere for analyses of quiet supersonic overflight
Authors: Loubeau Alexandra , Sparrow Victor W. , Doebler William , Rallabhandi Sriram K. , Lemaire Stephane , Normand Pierre-Elie , Liu Sandy R.
Published: November 2023

New reference day atmospheric conditions have been defined for future supersonic aircraft en route noise certification procedures. As field measurements are acquired, in a variety of atmospheric conditions, it is important to relate those measurements back to a common reference atmosphere to provide uniformity in method across applicants for noise certification. Because of the long propagation distances involved between the aircraft flight altitude and the ground, en route noise certification measurements can be substantially affected by the atmosphere. Properties, such as pressure, density, temperature, humidity, and winds, vary with altitude. Therefore, the definition of reference atmospheric profiles as a function of altitude are needed instead of the coarse layered atmosphere and homogeneous humidity used in subsonic aircraft landing and takeoff noise certification. Ground loudness levels from overflight of a quiet supersonic demonstrator concept, calculated with atmospheric data from sites across the world, were compared with the results from several candidate reference atmospheres to identify a reference that would minimize the required adjustment to certification test measurements. The existing ICAO 7488/3 profiles for temperature and pressure, combined with a modified ISO 5878 humidity profile, were found to offer the best results.
On the utilisation of the coupled-oscillator approach as a surrogate model for sound propagation in the vicinity of bubble groups
Authors: Ooi Andrew , Zhu Shuang J. , Skvortsov Alex , Manasseh Richard
Published: November 2023

The presence of bubble curtains have been shown to reduce the level of underwater noise propagation. This is due to the change in density and acoustic-impedance between the group of bubbles and the water. In addition, sound waves can be absorbed and scattered when they interact with bubble curtains. In this paper, it is shown that a mathematical model based on the discrete bubble model (DBM) and utilising the self-consistent coupled-oscillator theory is able to correctly predict the bubble collective resonance frequencies of 1D line, 2-D planar, and 3-D complex bubble cloud configurations. This framework can also accommodate polydisperse-sized bubbles. We use the DBM and conduct modal analysis on common 2-D and 3-D bubble curtain configurations and show that the fundamental modes in both configurations dominated the vibration of bubble curtains when subjected to an external acoustic source. In addition, it is demonstrated that the performance of the bubble curtain is most affected by the changes in the bubble size whereas the variations in inter-bubble spacing had no significant influence.
Acoustical characterization of concentrated bubbly media
Authors: Cohen Camille , Valier-Brasier Tony , Desailly Yann , Leroy Valentin
Published: November 2023

Bubbles are known to be strongly resonant acoustic scatterers. As such, their presence in a fluid, even for amounts of gas as low as 1%, highly impacts the propagation of acoustic waves. Ultrasounds are, thus, a great tool for bubble distribution measurements in opaque fluids. Additionally, diluted media models have been shown to have a good agreement with experiments at volume fraction below 1%. One of the aims of our study is to determine the limit volume fraction beyond which the models start to fail. To achieve that, we measure relfection and transmission of ultrasounds through bubbly media ranging from 5% to 60 % of gas volume fraction. Samples are polydisperse thin slabs with median radii ranging between 30 and 180 μm. Alongside experimental measurements, numerical simulations are carried out with monodisperse distributions. Up to 10%, we find a good agreement between the independent scattering approximation and our experimental results.
Wave transmission through acoustic lossy barrier by using non-Hermitian complementary metamaterial
Authors: Lee Ki Yong , Jeon Wonju
Published: November 2023

Complementary metamaterials (CMMs), characterized by negative effective mass density and moduli within a specific frequency range, hold the promise of significantly enhancing wave energy transmission across acoustic barriers. These materials operate by acoustically counteracting the barrier, thus offering an efficient conduit for wave propagation. However, when the intrinsic loss factor of the acoustic barrier is considered, the transmission performance of CMMs experiences a marked decrease. This decrement is notably severe, surpassing the theoretical expectations based solely on acoustic dissipation within the barrier. Delving into the depth of this issue, our research scrutinizes the far-reaching implications of the loss factor on wave transmission and takes a critical step forward by extending the effective properties of the complementary metamaterials from real to complex domain, an approach embodying the concept of non-Hermitian physics. Subsequently, we introduce a non-Hermitian CMM, a groundbreaking solution that maintains high transmittance despite the barrier's loss. It adeptly reconciles the impedance mismatch between the lossy barrier and the background medium, ultimately enabling perfect transmission.