bluuebunny/crossref_metadata_2025 huggingface dataset:
Flow visualization and aerosols in performance
Authors: Stockman Tehya , Hertzberg Jean , Kumar Abhishek
Published: May 2022

The COVID-19 pandemic has created a great deal of fear and uncertainty around whether aerosols from singers and musical instruments can transmit the virus. The World Health Organization has recognized that SARS-COV-2 is transmissible through aerosols. Outbreaks from choir performances, such as the Skagit Valley Choir, showed that singing brings potential risk of COVID-19 infection. Additionally, outbreaks from singing have resulted in superspreader events leading to many infections and deaths. There is less known about the risks of airborne infection from other musical performance, such as playing wind instruments or performing theater. Hence, aerosol generation in performance (playing brass and woodwind instruments, singing, and theater speech delivery) should be quantified, monitored, and mitigated. To tackle this issue our research questions were as follows: (i) What is the aerosol generation rate? (ii) How does air flow from the performer’s mouth/instrument and how does it disseminate into the environment? and (iii) What control methods can be employed to mitigate risk? In this study, we used a variety of methods, including flow visualization, aerosol and CO2 measurements, and computational fluid dynamics (CFD) modeling to understand the different components that can lead to transmission risk from musical performance and risk mitigation.
Ammonia chemistry: Sounds better with ultrasound
Authors: Amaniampong Prince N. , Humblot Anaelle , De Oliveira Vigier Karine , Jerome Francois
Published: May 2022

Hydrazine is a chemical of utmost importance in our society, either for organic synthesis or energy use. The direct conversion of NH3 to hydrazine is highly appealing, but it remains a very difficult task because the degradation of hydrazine is thermodynamically more feasible than the cleavage of the N−H bond of NH3. As a result, any catalyst capable of activating NH3 will thus unavoidably decompose N2H4. Here, we show that cavitation bubbles, created by ultrasonic irradiation of aqueous NH3 at a high frequency, act as microreactors to activate and convert NH3 to NH species, without assistance of any catalyst, yielding hydrazine at the bubble–liquid interface. The compartmentation of in-situ-produced hydrazine in the bulk solution, which is maintained close to 30 °C, advantageously prevents its thermal degradation, a recurrent problem faced by previous technologies. This work also points towards a path to scavenge .OH radicals by adjusting the NH3 concentration.
Speech-based biomarkers for automatic detection of GERD: A pilot study
Authors: Pietrowicz Mary , Kamboj Amrit , Yarlagadda Manoj , Buller Kevin , Ishikawa Keiko , Orbelo Diana , Leggett Cadman
Published: May 2022

This study explores the feasibility of detecting gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE) using acoustic features extracted from speech recordings. GERD is a common condition affecting up to 27.8% of adults in the US. Chronic GERD is associated with BE, the precursor to esophageal adenocarcinoma. An automatic screening tool for GERD would improve clinical outcomes by improving early detection. Biomarkers based on acoustic features of speech may hold promise as hoarseness often co-occurs with GERD. The study cohort consisted of 49 adults with and 63 without GERD based on esophagogastroduodenoscopy or ambulatory pH studies. Speech, including sustained vowels, sentences, and reading, was systematically recorded. Voice quality was validated through auditory-perceptualratings with three speech-language pathologists. Automated, cross-validated, search across multiple machine and deep learning model types was performed using the recorded speech. Detection of condition presence and severity are explored, and model performance is reported, along with an assessment of the ability of acoustic features to discern across conditions.
Cortical dynamics underlying speech planning in rapid conversational turn-taking
Authors: Castellucci Gregg A. , Kovach Christopher , Greenlee Jeremy , Long Michael
Published: May 2022

During conversation, silent gaps between speakers are typically 200ms or less—suggesting that speech planning often occurs while speakers listen to their partners’ turns. Though the psycholinguistic mechanisms of planning during turn-taking are well-studied, its neural underpinnings are largely unknown. Using intracranial electrocorticography in neurosurgical patient-volunteers, we delineated planning-related activity from dynamics underlying sensorimotor processes using an interactive question–answer paradigm (adapted from Bögels et al., 2015) and found that planning activity is largely restricted to a left hemisphere network centered on caudal inferior and middle frontal gyri. In a separate task, participants performed both speech and non-speech actions, and we found that this planning network is most active while planning spoken output. We then examined neural activity during unconstrained conversation and found that the identified planning circuit is active prior to participant turn onset and while participants listen to the turns of conversational partners. Finally, in preliminary direct cortical stimulation experiments, we found that perturbation of this planning network results in significantly longer reaction times and lexical errors but not gross articulatory disruptions. In conclusion, using controlled interactive language tasks, we uncovered a speech-selective cortical planning circuit that is active during natural conversation and required to execute rapid turn-taking.
Acoustic Voice Analysis during Phonation Onset, Measured from High-Speed Videoendoscopy in Connected Speech
Authors: Henry Trent M. , Deliyski Dimitar , Zacharias Stephanie R. , Naghibolhosseini Maryam
Published: May 2022

Adductor spasmodic dysphonia (AdSD) is a neurological voice disorder, which affects the control of intrinsic muscles of the larynx during speech. Our previous research has shown that high-speed videoendoscopy (HSV) can be used to measure the glottal attack time for patients with AdSD during connected speech. This study builds upon that to analyze the acoustic signal during the phonation onset and prephonatory adjustments. The phonation onset events are quantified using the HSV data that were obtained simultaneously with the acoustic data. We analyze the power and energy waveform of the acoustic signal during vocal folds’ first contact, first oscillation, and transitory behaviors, extracted from high-temporal resolution HSV data. The data were obtained from five patients with AdSD and five vocally normal participants. The data were recorded while the participant produced: 2 productions of vowel /i/ at habitual pitch and loudness, 2 with a soft glottal attack and 2 with a hard glottal attack, six CAPE-V sentences, and the “Rainbow Passage.” The HSV system included a monochrome high-speed camera coupled with a flexible nasolaryngoscope. The results of this study could assist for more accurate clinical management of adductor spasmodic dysphonia.
Oral vibratory sensation at different laryngeal and semi-occluded vocal tract configurations during voice production
Authors: Zhang Zhaoyan
Published: May 2022

Voice therapy aimed at improving vocal efficiency, such as resonant voice therapy or semi-occluded vocal tract exercises, often emphasizes vibratory sensations in the front part of the vocal tract during phonation. It remains unclear what laryngeal and vocal tract adjustments are elicited in patients by this emphasis on oral vibratory sensations and how these adjustments improve voice production. This study aims to identify laryngeal and vocal tract adjustments that maximize oral vibratory sensations during phonation, as quantified by the oral sound pressure level (SPL), at different laryngeal and semi-occluded vocal tract conditions in a three-dimensional phonation model. Results show that maximum oral SPL is reached at intermediate vocal fold adduction conditions. Epilaryngeal tube narrowing further increases the oral SPL in an open vocal tract, but this effect is much reduced and even reversed in a semi-occluded vocal tract, due to the reduced sensitivity of the first formant to epilaryngeal manipulation in a constricted vocal tract. These findings suggest that emphasis on oral vibratory sensations generally elicits a laryngeal configuration that is neither too tight nor too open. In a semi-occluded vocal tract, this emphasis may also reduce the degree of epilaryngeal narrowing as often observed in recent imaging studies.
Dynamic targets in second language vowel articulations
Authors: Oakley Madeleine
Published: May 2022

This study examines L1 English-L2 French vowel productions, with the goal of exploring whether representing vowel targets as dynamic rather than “steady-state” better predict L2 production patterns. It is hypothesized that learners will transfer L1 vowel dynamic information to produce L2 vowels if the two are perceived as “similar,” but it is unclear whether learners will transfer dynamic vowel information to “new” L2. As such, six L1 English-L2 French learners completed production tasks in English and French with the target vowels /i, u, e, o/ and /y, ø/ in real words. Participants were recorded using a stabilization headset attached to an ultrasound probe and microphone. F1 and F2 measurements and tongue contours were extracted at three timepoints throughout the vowel duration. Results shows that while learners produce L2 French vowels /i, e, u, o/ with a similar amount of formant and gestural movement to L1 vowels, they do not transfer midpoint F1-F2 values. Learners do produce new L2 vowels /y, ø/ with similar formant and gestural movements to English vowels. The results of this study indicate that learners transfer dynamic acoustic information and articulatory gestures from their L1 to produce L2 vowels, which has implications for the representation of vowels.
The degree and time course of nasal coarticulation across communicative contexts: A study of the LUCID corpus
Authors: Guo Zhe-chen , Smiljanic Rajka
Published: May 2022

We analyzed the degree and time course of coarticulatory vowel nasalization in hyperarticulated clear speech produced in real and imagined communicatively challenging conditions from the LUCID corpus (Baker & Hazan, 2011). Southern British English speakers completed an interactive spot-the-difference task in pairs when there was no overt communication barrier (NB), when the partner was non-native (L2), and when one speaker’s speech was vocoded (VOC) or mixed with talker babble (BABBLE). They also read sentences conversationally (READ-CO) and clearly (READ-CL). The results showed significantly greater overall keyword vowel nasalization in the BABBLE and L2 conditions than in NB, READ-CO, and READ-CL, as well as in VOC than in NB and READ-CO. READ-CL and READ-CO did not differ significantly. Examining vowel nasalization over time revealed that the significant differences emerged, on average, at 7.4% into the vowel. Speakers increased coarticulatory nasalization early in the vowel when producing hyperarticulated speech in response to a real communicative barrier, consistent with the idea that nasal coarticulation facilitates speech processing by cueing upcoming segments. It remains to be determined why nasal coarticulation is increased while coarticulation for other consonant-vowel sequences is decreased during the production of hyperarticulated listener-oriented speaking styles (Guo and Smiljanic, 2021).
Uncertainty reduction in matched field inversion using Gaussian Processes
Authors: Michalopoulou Zoi-Heleni , Gerstoft Peter
Published: May 2022

Gaussian Processes have been shown to be an effective tool for predicting an acoustic field in the ocean at a densely populated virtual array. This property is employed in this work for pre-processing acoustic data before these are used for source localization and geoacoustic parameter estimation using matched-field inversion (MFI). The process increases the accuracy of MFI as uncertainty in the estimation process is reduced. Via the application of Gaussian Processes, the data are denoised and interpolated and the new, enhanced fields are used as input to MFI along with replicas calculated at the virtual receivers at which field predictions are made. Kernel functions, implicit in the implementation of Gaussian Processes, quantify the correlation among field values at neighboring spatial points. Employing different kernels, the approach is tested on synthetic and real data with both an exhaustive search and genetic algorithms and is found to be superior to conventional Bartlett MFI in source localization and geoacoustic inversion. [Work supported by ONR.]
Applying unsupervised machine learning clustering techniques to hospital soundscapes
Authors: Hummel Kenton , Ryherd Erica E. , Lowndes Bethany
Published: May 2022

Noise in hospitals can be problematic for both patients and staff and is consistently rated poorly on national patient satisfaction surveys. Previous studies have linked negative outcomes of hospital noise to numerous patient and staff challenges, such as reduced sleep and disrupted communication. Existing articles and guidelines commonly use equivalent sound pressure level as a primary noise metric. Additional insights into typical sound levels experienced by occupants can be found through more detailed statistical analyses of sound, such as by applying unsupervised machine learning clustering techniques. In this talk, clustering techniques will be explored in an effort to provide a more detailed analysis of the soundscape and various patterns of room activity. Noise data collected in three adult, inpatient hospital units will be analyzed using clustering techniques and compared against patient satisfaction scores. This more thorough, statistical characterization of the hospital soundscape can lead to better understanding of patterns of noise conditions and resultant occupant perceptions.
Integrated healthcare acoustics for patients, patient advocates, and staff in environments of care
Authors: Sweitzer Glenn E.
Published: May 2022

COVID surges have demonstrated worldwide that overloaded critical care facilities cannot transform environments of care rapidly enough to satisfy patient, patient advocate, or staff expectations. Healthcare acoustics is identified as a vital yet understudied factor, linking the front lines of healthcare to patient well-being. Acoustic concerns are categorized, and existing architectural hardware and software means and proposed strategies are here discussed to be applied in both new and existing critical care facilities. Priority concerns focus on staff verbal and machine communications between single patient rooms with integral toilet/shower, adjacent corridors, nurse stations, and remote staff locations. The intent is to maintain uniformly high patient/staff communications and relevant documentation (e.g., for continuity of care, and liability) across all shifts. Integrated visual and acoustic communications between staff and equipment are explored, including projected machine display images minus noisy signals. Staff speech, background masking, and messaging to patients are considered via an “acoustic pillow,” and via a wireless headset for staff, permitting hands-free focus on empathetic patient care. HVAC can be supplied via low-velocity displacement air, served via perimeter floor ducting, and exhausted via toilet/showers. Integrated healthcare acoustics, arguably, can reduce patient and staff stresses critical to recovery and retention, respectively.
Impact of sound intervention on patient wellbeing during pediatric peritoneal dialysis
Authors: Wang Hsin-Hui , Tang Yi-Hsuan , Tsaih Lucky S. , Chen Julie Chia-Ping , Lin Chien-Hung , Chen Hui-Lan
Published: May 2022

Peritoneal dialysis (PD) is a treatment suitable for pediatric patients for less food restrictions, better school attendance and requires less hospital visits than hemodialysis. However, it may still cause stress and affect children’s wellbeing as children with end-stage renal disease have to undergo treatment four times a day, 30 min each time. Thus, sound interventions used to improve children’s comfort during PD treatments are worthy of investigating and are the aim of this study. Respondents will include PD patients under 18 years of age. Three types of sound will be played during PD treatment via headphone, including natural sound, classical music, and songs chosen by individual patient. Vital signs will be measured with oximeter to include heart rate, respiratory rate, O2 saturation, and blood pressure. Neurological activities will be recorded by electroencephalography (EEG). PD treatment efficiency will be measured by calculating fluid removal volume. Questionnaires will be given to measure the subjective wellbeing of respondents. Correlations among chosen music, vital signs, EEG readings, treatment efficiency, and patient’s subjective wellbeing will be investigated. The findings of this research will add knowledge to improve subjective patient wellbeing and dialysis efficiency by acoustic interventions.
Relaxation response with gentle stream sound: A study using brainwave
Authors: Tantra Jennifer , Juan Shiang-I , Tsaih Lucky S. , Chiang Wei-Hwa
Published: May 2022

Respite place in healthcare facility has been introduced and promoted in USGBC LEED to reduce stress and fatigue for caregivers, patients, and their families. Studies showed that people stay in natural environment can experience a sense of wellbeing and also suggested gentle stream water sound is highly associated with “relax” listening impression. Thus, as gentle stream is one of the familiar nature elements and is often used as a landscape architecture element for relaxation along with greens in respite place, the objective of this study was to learn the effect of the relaxation state with gentle stream water sound by studying the alpha brainwave response and physiological responses such as heart rate and blood pressure of 20 participants. During the evaluation, stress inducing period and relaxation period were conducted. Two-sample t-test was used to find out if there were any significant changes in participants’ brainwave and physiological responses. The results showed that based on alpha brainwave, more female participants experienced relaxation state than males. After listening to the water sound, the systolic blood pressure showed the most obvious changes, and heart rate is slower.
Tribute to Whitlow Au
Authors: Kastelein Ronald A.
Published: May 2022

Whitlow Au has played a large role in my life both as a friend, as editor of manuscripts I submitted to JASA and a book on bycatch of harbor porpoises, as co-authors of manuscripts we submitted together to JASA, as author of manuscripts Whit submitted to sensory system books of which I was a co-editor. Whit also proposed me as a Fellow of the Acoustical Society of America. We collaborated on several research project, which were conducted in pools at the cetacean rehabilitation center of Dolfinarium Harderwijk, the Netherlands, in a large floating pen at Neeltje Jans, the Netherlands, at the Hawaii Institute for Marine Biology, Oahu, USA, in a large fish pool at Jacobahaven, and at the Netherlands and at SEAMARCO Research Institute, Wilhelminadorp, the NL. The publications in Whit and I are co-authors are used as points of departure of the talk. The studies are described in chronological order, and the gist of each study is given.
Spatio-temporal patterns of blue and fin whale sound production identified in National Oceanic Atmospheric Administration-National Park Service Ocean Noise Reference Station Network recording sites in the Pacific Ocean
Authors: Pearson Emma , Wall Carrie
Published: May 2022

The ability of sound to travel long distances, especially in lower frequencies, makes it an effective way for organisms to communicate in marine environments. Passive acoustic monitoring (PAM) is an essential method to study low-frequency sound in marine ecosystems. The NOAA-NPS Ocean Noise Reference Station Network (NRS) project is a long-term study that utilizes PAM to monitor low-frequency (<2kHz) soundscapes throughout the U.S. exclusive economic zone. While these data have been analyzed to understand large scale patterns, assessment of specific sound sources is an area where these datasets can provide new insights. This study used a call energy index (CEI) to assess blue whale and fin whale sound production from three NRS recording sites in the Gulf of Alaska, off the Olympic coast, and near the Channel Islands between 2014 and 2020. We present the diel and seasonal patterns detected for both species and compare them to the decidecade bands assessed for the recording sites. Understanding the song production and migration patterns for endangered blue whales and fin whales is essential for effective conservation efforts. By utilizing PAM and efficient detection methods such as CEI, researchers gain the ability to process large amounts of bioacoustic data and better understand the migratory behaviors of endangered marine species.
Assessing intra-individual consistency in humpback whale song production using animal-borne acoustic recorders
Authors: Zeh Julia , Lammers Marc , Pack Adam , Parks Susan
Published: May 2022

Studying individual variation in vocal behavior can provide insight into its functions, stability, and mechanisms. Collecting such data at the scale of the individual can be facilitated using animal-borne tags. Here, we use archival suction-cup acoustic recording tags to investigate intra-individual variation in male humpback whale song production. Humpback whale song is a complex and hierarchically structured vocal sequence of 4-7 repeated phrases that are comprised of different units. Repeated songs are termed song sessions. To investigate how consistent song production is within the song session of an individual whale, we deployed suction cup-attached acoustic recording tags on humpback whales in the Hawaiian Islands Humpback Whale National Marine Sanctuary during the 2018–2022 breeding seasons. We analyzed tag data from nine whales to assess intra-individual variation in song structure and syntax as well as differences in the acoustic properties of song units across each song iteration. Each tag contained between 4 and 24 song iterations, and song session recordings varied between 45 minutes and 5 hours. Across individuals, the most variable song iterations occurred at the beginning of a song session. All individuals showed variation in syntax and unit production throughout a session; however, some singers were more consistent than others.
Investigating the link between intensity of lung ultrasound vertical artifacts and penetration depth of ultrasound waves, in silico study
Authors: Mento Federico , Demi Libertario
Published: May 2022

Lung ultrasound (LUS) is nowadays widely applied for lung surface evaluation. In particular, LUS is often based on the analysis of vertical artifacts, which correlate with various pathologies but whose genesis is not fully comprehended yet. To better understand the phenomena causing these artifacts' appearance, numerical simulations can represent a powerful tool. Specifically, we present a simulation study (k-Wave MATLAB toolbox) that investigates whether a link exists between the intensity of these artifacts and the penetration depth of ultrasound waves through the lung parenchyma. The size of the simulated numerical domain is 4 cm × 2 cm, with the simulated lung surface located at a depth of 2 cm. Different alveolar structures were modeled by varying the alveolar diameter (from 40 to 800 μm), the inter-alveolar axial-spacing (from 40 to 790 μm) and inter-alveolar lateral-spacing (from 10 to 100 μm). For each configuration, Gaussian pulses (with bandwidth equal to 0.5 MHz at −6 dB) having different center frequencies (from 1 to 5 MHz) were transmitted without focusing (plane wave imaging). Results highlight how the artifacts' intensity seems to be independent from waves' penetration depth.
Applying ultrasound phase-change contrast agents to guide therapeutic intervention in type 1 diabetes
Authors: Benninger Richard K.
Published: May 2022

Ultrasound is a widely deployable and cost-effective clinical imaging modality. However, conventional microbubble contrast agents are restricted to the vasculature. Sub-micron nanodroplet (ND) phase-change agents can be vaporized into micron-sized bubbles, serving as a microbubble precursor. In principle, the enhanced permeabiltiy and retention effect can be used with sub-micron NDs to detect injured tissues. Methods to detect type1 diabetes (T1D) progression prior to clinical diagnosis are needed. T1D results from autoreactive T-cells infiltrating the islets of Langerhans, destroying insulin-producing beta-cells. Overt disease takes years to present and at diagnosis there is substantial beta-cells loss. Therapeutic intervention to preserve beta-cell mass is hampered by an inability to follow pre-symptomatic T1D progression and tracking whether therapeutic interventions are impacting disease progression. We will present ultrasound imaging of phase-change nanodroplet (ND) contrast-agent accumulation within the islet. ND accumulation is dependent on immune infiltration, therefore tracks pre-symptomatic T1D development and progression to diabetes. Measurement of ND accumulation detected pre-symptomatic T1D earlier and with greater sensitivity compared to existing measurements of circulating autoantibodies. This provides an opportunity to guide early therapeutic treatments to prevent T1D.
Ultrasound-stimulated, drug-loaded bubbles for cancer therapy
Authors: Matsuura Naomi
Published: May 2022

Non-invasive, focused ultrasound in combination with microbubbles have previously been used for targeted drug delivery. Focused ultrasound-stimulated microbubbles can increase local tumour blood vessel permeability such that co-injected chemotherapeutics can diffuse preferentially into tumour tissue. Focused ultrasound and microbubbles have also been used to initiate other local bioeffects, for example, to damage tumour vessels for mechanically induced vascular disruption therapy, which can profoundly increase the efficacy of a variety of anticancer drugs. In this talk, the development of new acoustically-active bubbles that are capable of carrying and releasing therapeutic concentrations of hydrophobic and hydrophilic chemotherapeutic drugs will be introduced. Agents that are entirely composed of FDA-approved components are preferred as they may permit expedited translation into clinical use. Trade-offs among size, stability, drug-loading, and in vivo performance between bubble variants will be overviewed. Challenges and opportunities identified through recent efforts towards achieving cancer therapy potentiation in small animal cancer models will also be discussed.
Biomimetic lung surfactant nanodrops for ultrasound imaging
Authors: Borden Mark , Thomas Alec , Song Kang-Ho , Upadhyay Awaneesh , Papadopoulou Virginie , Ramirez David , Benninger Richard K. , Lowerison Matthew R. , Song Pengfei , Murray Todd
Published: May 2022

Nanodrops comprising a perfluorocarbon liquid core can be acoustically vaporized into echogenic microbubbles for ultrasound imaging. Packaging the microbubble in its condensed liquid state provides some advantages, including in situ activation of the acoustic signal, longer circulation persistence, and the advent of expanded diagnostic and therapeutic applications in pathologies, which exhibit compromised vasculature. One obstacle to clinical translation is the inability of the limited surfactant present on the nanodrop to encapsulate the greatly expanded microbubble interface, resulting in ephemeral microbubbles with limited utility. In this study, we examine a biomimetic approach to stabilizing an expanding gas surface by employing the lung surfactant replacement, Beractant. Lung surfactant contains a suite of lipids and surfactant proteins that provides efficient shuttling of material from bilayer folds to the monolayer surface. We hypothesized that Beractant would improve stability of acoustically vaporized microbubbles. To test this hypothesis, we characterized Beractant surface dilation mechanics and revealed a novel biophysical phenomenon of rapid interfacial melting, spreading, and re-solidification. We then harnessed this unique spreading capability to increase the stability and echogenicity of microbubbles produced after acoustic droplet vaporization for in vivo ultrasound imaging. Such biomimetic lung surfactant-stabilized nanodrops may be useful for applications in ultrasound imaging and therapy.
Feasibility of cavitation nucleation in the crystalline lens
Authors: Ganeau Alice , Lafond Maxime , Ben Moussa Olfa , Mion Charles , Poinard Sylvain , Mascarelli Frédéric , Catheline Stefan , Thuret Gilles , Gain Philippe , Lafon Cyril
Published: May 2022

Presbyopia is the age-related stiffening of the crystalline lens, reducing near vision. We propose ultrasonic cavitation to interact with the lens structure and restore its flexibility. Here, we present early results on the feasibility of the technique. First, the cavitation threshold was determined: the focus of a 4-elements transducer was placed in the lens nucleus in a porcine eye, and signals emitted in the focal area were acquired using an imaging array and reconstructed using frequency-domain passive cavitation imaging (PCI) with Richardson-Lucy deconvolution. Inharmonic emissions inside the lens were calculated, and we evidenced two distinct populations: low and high amount of signal inside the lens, when cavitation was absent or present, respectively. Peak negative pressure of 23 MPa for 20 μs pulses at 1.1 MHz provided a clear chance of nucleating cavitation with our system. Exposures were performed after 10 s of cavitation using a PRF of 250 Hz. Cavitation clouds were clearly visible in B-mode images for both 6-months old and 3-years old porcine eyes. The absence of cataract was confirmed on transparency images, and histology revealed no damages to the lens structure. These preliminary results are encouraging towards the application of cavitation in the crystalline lens.
Acoustics instruction in a pandemic world
Authors: Ramsey Gordon P.
Published: May 2022

COVID-19 has required a change in instruction at all levels. Fortunately, the technology exists to enable us to give quality education to our students. In acoustics, the wealth of existing online materials makes it practicable to motivate and enlighten our students to the beauty of our subject. Some of the key elements used in our courses can be presented effectively using auxiliary materials and web technology. Like many instructors, I provide PowerPoints with sound bites, text readings with discussion topics, and detailed supplements. Regular discussions are important to keep up motivation. “In class” labs can be done either live or online via Zoom or equivalent. Analysis and reports are done as homework. Exam security is an issue that can be minimized by alternate means. Assessments include short and frequent quizzes, essays and discussion writeups, lab reports, homework for practice, and a final project combining musical and physical aspects of the course. This project has been a more accurate assessment than a final exam. There is a wealth of web materials that are available on various sites. This talk will provide an overview of these elements as they apply to musical acoustics courses and strategies used to implement them.
Implementing a flipped classroom model to teach an introductory musical acoustics course
Authors: Morrison Andrew C.
Published: May 2022

Because of the COVID-19 pandemic and our institution's response to the emergency, our musical acoustics course was delivered exclusively online for a full academic year, followed by a semester where only the lab component was in-person. A library of videos was developed to provide this course online. The videos contained the lecture content for the entire course. A flipped class model was adopted upon returning the course to a face-to-face modality. Students were assigned to watch the videos of class lecture material at home instead of expecting to hear that material presented in the classroom. Classtime was exclusively reserved for laboratory activities, answering student questions, and applying concepts covered in the videos to problems in preparation for class assessments. The benefits and challenges of this course delivery method will be addressed.
Teaching a graduate course on the acoustics of musical instruments over Zoom from my house during COVID-19
Authors: Russell Daniel A.
Published: May 2022

During Spring 2021, I taught a graduate course, Acoustics of Musical Instruments, to a blended enrollment of resident and distance students. Course content focused on wind (woodwind and brass) and stringed instruments with heavy reference to published literature. This was my third time teaching this course, but the first time teaching it entirely over Zoom from my house with all students also participating only on Zoom. It was also the first time teaching without access to laboratory equipment that would have allowed for interactive classroom demonstrations and out-of-class student projects. Although several students were accomplished musicians and had access multiple musical instruments in their homes, very few students had any access to test equipment that would have allowed for meaningful measurements or experimental projects. To offset this lack of access, I purchased several musical instruments for demonstrations and simple experiments that I could perform from my house and shifted the emphasis for student deliverables to written literature review summaries of published papers. This presentation will describe simple hands-on activities students carried out, demonstrations I was able to perform from my house with limited data analysis capabilities, and the benefits of having graduate students do literature reviews.
Acoustical measurement and analysis of an Atlas V launch without solid rocket boosters
Authors: Cunningham Carson F. , Anderson Mark C. , Moats Levi T. , Gee Kent L. , Hart Grant W. , Hall Lucas K. , Campbell Steven C.
Published: May 2022

In September 2021, an Atlas V rocket without solid rocket boosters was launched from Vandenberg Space Force Base, California, carrying the NASA/USGS Landsat 9 satellite. In this launch configuration, the plumes from the RD-180 engine’s two nozzles are unobstructed, providing the opportunity to analyze the sound generated by a liquid-fuel rocket engine with an azimuthally asymmetric nozzle geometry. Acoustical data were collected at various locations surrounding the launch pad, ranging from a few hundred meters to several kilometers. This paper discusses an overview of the measurement logistics, the types of analyses that may be performed using these data, and an initial analysis of the azimuthal variability of the overall sound pressure level and spectra.
Directional processing in assessment of wind turbine noise
Authors: Sutin Alexander , Salloum Hady , Sedunov Alexander , Sedunov Nikolay
Published: May 2022

Assessments of wind turbine generator (WTG) noise are required to comply with the US Environmental Agency and local governments and avoid legal action that may result of non-compliant operation. Current methods for WTG noise measurements require the comparison of long-term sound data recorded before and after a WTG installation. These measurements must be conducted during several months for various wind speeds and environmental conditions. Such measurements are complicated due to the presence of multiple sources other than noise not from WTG, including intermittent and fluctuating sources. The application of directional processing can help localize and identify the sources responsible for increased sound levels at any given moment and to estimate the contribution of the other than WTG sources to the whole sound level. Stevens has developed various acoustic systems with several sensors that provide directional processing of sounds that were previously applied for detection, tracking and classification of small boats, divers, small aircraft, and drones. We propose modifications of such systems for directional sensing of WTG noise at long distances in the frequency band relevant for WTG noise measurement.
Acoustic optimization of a contra-rotating propeller rig
Authors: Casagrande Hirono Fabio , Torija Martinez Antonio , Elliott Andrew
Published: May 2022

With the advance of unmanned aerial vehicles as a viable alternative for urban transportation, it is imperative that these vehicles have a low impact on community noise. Contra-rotating propeller technologies offer interesting advantages over traditional single-propeller equivalents, such as improved aerodynamic performance and redundancy in case of failure, but can be exceedingly noisy when not carefully designed. This work presents a parametric study for the acoustic optimization of a custom-made contra-rotating propeller rig. The rig consists of two commercially available motors mounted on a rotating stand built in-house and mounted inside an anechoic chamber. A far-field microphone arc is used to collect acoustic pressure data, and a load cell is used to measure total thrust. We investigate the effect of variations in the number of blades (between 2 and 6 on both rotors) and axial spacing (between 0.1 and 1 rotor diameter) on the radiated noise, while adjusting the rpm to maintain constant thrust. Overall sound pressure levels, far-field spectra, and directivities (overall SPL, tones, and broadband) are assessed to determine trade-offs and optimal choices in designing a contra-rotating propeller rig.
Use of an acoustic camera together with modeling of a unique crypto-mining facility
Authors: Albion-Poles Iliana
Published: May 2022

Crypto-currency mining facilities have become more and more common over the last few years, but there is no standard for construction or noise mitigation. Many noise issues are encountered after the facilities are complete and operating. Mining facilities can contain thousands of “miners” which are quite loud. Often, the manufacturers cannot supply reliable sound data. The miners have extreme power and ventilation requirements, which introduce additional noise sources and paths. The use of modeling software is often a great tool to predict the noise of a future project, rank order multiple noise sources, or to determine what mitigation strategies will be most effective. Using an acoustic camera and standard sound level measurements together with a noise model of an existing facility can better pinpoint the dominant noise sources and facilitate the type and placement of noise mitigation measures. This presentation will show how the multiple technologies were used together to identify the problem noise sources and paths and to evaluate mitigation measures.
Chiller compressor sound emission analysis
Authors: George Hezekiah , Wang Jingdou , Bryant Becky
Published: May 2022

Building occupants rely on heating, ventilation, and air conditioning (HVAC) units for comfort. Chillers are HVAC units that serve the purpose of cooling a building. Because chillers are often placed on top of or near the building, the noise from the chiller can adversely affect the occupants. A crucial component of all chillers, the compressor, is responsible for the majority of the noise produced by the chiller. In addition to designing for cooling efficiency, engineers must also consider how quiet and acoustically efficient a chiller is. In this project, we aim to develop an enclosure to house the compressor, therefore, reducing the magnitude of noise that is emitted. We begin by studying an empty cavity model in an acoustical software and observing its modes, resonant frequencies, and corresponding pressure distributions. Next, we placed a sound source within the cavity and then analyzed the acoustics frequency response of the cavity without and with a sound-absorbent material. We then proceeded to analyze a FEM model of the compressor and its dynamic frequency response due to the bearing force. After further analysis of the compressor sound emission, simulations will be made for the compressor with the designed enclosure and sound-absorbent material.
Implementation of a sonic boom propagation algorithm with the augmented Burgers equation
Authors: Jäschke Jacob J. , Liebhardt Bernd
Published: May 2022

For the purpose of sonic boom carpet determination for an optimized routing of supersonic aircraft around landmasses, a sonic boom propagation code was implemented at the Institute of Air Transportation Systems. The implementation is based on the well-known augmented Burgers equation for stratified atmospheres and extends the sole geometric ray tracing that has been used at the institute to determine the lateral cutoff distance of sonic booms so far. For the quantification of sonic boom signatures on ground, algorithms for the computation of noise metrices, namely, the perceived level of noise Stevens Mk VII (PL) and the sound exposure level (SEL) with several frequency weightings are also implemented. This work describes the implementation of the sonic boom propagation algorithm and the methods used for loudness calculation briefly. For the evaluation of the implemented code, pre-defined cases from the Third Sonic Boom Prediction Workshop are simulated, and the computed results are compared to the published results of that workshop. The similarities and differences are discussed in detail, such that the general implementation of the propagation code can be verified, whereas potential inaccuracies, especially for the off-track determination, can be detected and quantified.
A spatial averaging of sonic boom waveforms
Authors: Lonzaga Joel B.
Published: May 2022

Sonic booms generated by conventional supersonic aircraft are influenced by turbulence in the atmospheric boundary layer through which they propagate. The turbulence effects lead to random variability of the sonic boom waveforms measured on the ground, complicating the prediction of such waveforms. While some of the waveforms have been described as N-waves with spikes immediately after the shocks, others measured a few hundreds of feet away tend to be rounded. The current paper presents an analysis method that uses a spatial averaging of an ensemble of measured waveforms to obtain a mean waveform and higher-order statistical moments. The statistics obtained are anticipated to be useful in characterizing the waveforms generated by any supersonic vehicle. They will also be useful for validating theoretical and semi-empirical models used for predicting turbulence effects on sonic booms. This paper discusses the advantages and disadvantages of spatial averaging in the time domain and the frequency domain. Preliminary results indicate that the mean waveforms have rise times larger than those obtained using a sonic boom propagation model that does not account for the turbulence effects, suggesting that turbulence effects may not be ignored.
Review of noise metric sensitivities for analysis of quiet supersonic overflight
Authors: Loubeau Alexandra
Published: May 2022

Six different noise metrics (PL, ASEL, BSEL, DSEL, ESEL, and ISBAP) are currently used to quantify sonic boom levels from overflight of supersonic aircraft. A previous meta-analysis using laboratory subjective data identified these metrics, each of which correlated well with human perception of low-boom sounds both indoors and outdoors. Because the analysis did not identify a single metric that was significantly superior, no internationally agreed-upon metric has been chosen for the quiet supersonic aircraft noise certification procedures currently under development. Other analyses of metric sensitivities using existing empirical and simulation datasets, however, have shown significant differences between metrics. Variability of metrics due to macro-atmospheric effects and atmospheric turbulence perturbations have been explored, as well as variability in measurements due to microphone setup configurations, array layouts, and ambient noise effects. This paper reviews these prior studies, summarizes the current understanding of metric sensitivities, and discusses how they may impact future downselection of metrics for certification procedures.
Designing an array for acoustic manipulation of kidney stones
Authors: Ghanem Mohamed A. , Maxwell Adam D. , Sapozhnikov Oleg A. , Bailey Michael R.
Published: May 2022

Remote acoustic manipulation of objects in three dimensions has been achieved through acoustic radiation forces imparted by designed acoustic beam traps. This technology can be used as a noninvasive medical tool to control foreign objects in the body. Success of this technology requires the ability to transmit complex beam shapes through the tissue while maintaining stable and robust acoustic traps. Vortex beams and other acoustic beam traps were synthesized using a 1.5 MHz, focused, multi-element array to trap and manipulate glass spheres mimicking stones. Measurements of the radiation forces agreed with calculations to within <10%. The strength of the trapping stability and steering range of the acoustic traps were achieved by controlling the pulsing directionality to eliminate rotational instability, geometrical shape of the beam relative to target size, and acoustic power of the beam. Spheres were noninvasively moved along predefined paths in the urinary bladders of pigs without morphological injury. To further improve the technology of remote manipulating of kidney stones, simulations and experiments were used to define a design and parameters of a 256-element array to move 2–5mm stones distances up to 3 cm in a kidney. [Work supported by NIH P01-DK043881 and APL SEED Fellowship.]
Modeling the effects of modulated radiation pressure using a new acoustic lens
Authors: Abawi Ahmad T. , Marston Philip L. , Kirsteins Ivars P. , Fortuner Auberry R. , Smith Sterling M. , Daniel Timothy D.
Published: May 2022

Modulated radiation pressure (MRP) is a method of utilizing the acoustic radiation force by using a double-sided suppressed carrier modulated (DSB-SCM) signal. This produces a modulated signal that oscillates at twice the modulation frequency. This process facilitates target detection and classification by using a high-carrier frequency to probe the target and shake it with the low-modulation frequency, which can be designed to be commensurate with the vibrational modes of the target. A frequency sweep can estimate the target resonant frequencies, while a physical scan along its length can estimate its mode shapes. Recently, a series of experiments were conducted at Washington State University with a newly designed and fabricated acoustic lens with a one-meter focal length. These experiments demonstrated that the first few bending modes of scaled targets like a solid aluminum cylinder and an open-ended aluminum cylindrical shell could be excited by MRP at a standoff distance of one meter and target mode shapes were measured using a physical scan. In this presentation, we show modeling results that confirm experimental findings: (1) estimation of target resonant frequencies using a frequency sweep and (2) estimation of target mode shapes using a physical scan.