bluuebunny/crossref_metadata_2025 huggingface dataset:
A Vision-Based Human Digital Twin Modeling Approach for Adaptive Human–Robot Collaboration
Authors: Fan Junming , Zheng Pai , Lee Carman K. M.
Published: April 2023

Human–robot collaboration (HRC) has been identified as a highly promising paradigm for human-centric smart manufacturing in the context of Industry 5.0. In order to enhance both human well-being and robotic flexibility within HRC, numerous research efforts have been dedicated to the exploration of human body perception, but many of these studies have focused only on specific facets of human recognition, lacking a holistic perspective of the human operator. A novel approach to addressing this challenge is the construction of a human digital twin (HDT), which serves as a centralized digital representation of various human data for seamless integration into the cyber-physical production system. By leveraging HDT, performance and efficiency optimization can be further achieved in an HRC system. However, the implementation of visual perception-based HDT remains underreported, particularly within the HRC realm. To this end, this study proposes an exemplary vision-based HDT model for highly dynamic HRC applications. The model mainly consists of a convolutional neural network that can simultaneously model the hierarchical human status including 3D human posture, action intention, and ergonomic risk. Then, on the basis of the constructed HDT, a robotic motion planning strategy is further introduced with the aim of adaptively optimizing the robotic motion trajectory. Further experiments and case studies are conducted in an HRC scenario to demonstrate the effectiveness of our approach.
Burst of Internally Pressurized Steel Torispheres
Authors: Błachut J.
Published: April 2023

The paper begins with derivation of true stress–true strain data, including postnecking section. Available results of past uni-axial tests on round 10 mm diameter and 200 mm long mild steel samples are the basis of the conversion. The steel in question was used to manufacture ten torispherical domes that were in the past tested for burst. Hence, the relevance of matching material model is necessary for the finite elements (FE), analyses. In the past, plastic instability and constraints on the magnitude of plastic strains were postulated as criteria for the burst of internally pressurized torispheres. These criteria for burst pressure are being examined and benchmarked against the tests. The current paper, using the FE analyses, shows that modification of constraints on plastic strains has only marginal effect on the burst which still remains on the unsafe side of test data by a sizeable margin. The same is found to be true for plastic instability criterion. Subsequent computations moved back to the use of engineering stress–strain. Then, two types of computing are carried out here, based on multisegment and bilinear modeling of material. Computed results of burst pressure follow the test data to within (−6%, +10%). These results are far better than all the previous.
Flow and Conjugate Heat Transfer of Swirl Chamber With Micro-Ribs in Turbine Vane Leading Edge
Authors: Han Shaohua , Zhang Runsheng , Xing Jiangjiang , Song Yuanyuan , An Na , Huo Tianyi , Zhou Leping , Li Li , Zhang Hui , Du Xiaoze
Published: April 2023

Swirl cooling can provide effective protection for the turbine vane leading edge (LE). In this paper, a swirl cooling model for improving the turbine vane heat transfer is established. The model includes the high-temperature mainstream region, LE region, and swirl cooling region. The conjugate heat transfer (CHT) method is used to examine the influence of wall structures on swirl cooling. Then, the best surface structure in the studied range is selected to further analyze the impact of the coolant inlet mass flow. The results show that the circumferential micro-rib structure has a more excellent performance in both fluid flow and cooling performance. The hindering effect of the micro-ribs can effectively avoid the development of axial cross-flow, thus enhancing the heat transfer with a small friction loss increment and providing a lower surface temperature and more uniform temperature distribution. When the inlet mass flowrate improves, the thermal performance factor increases and the LE temperature decreases gradually. Under the same pumping power condition, the circumferential micro-ribs structure has higher heat transfer efficiency. This investigation can provide a new design for further improving the thermal performance of swirl cooling for turbine vanes.
Film Cooling Comparison of Full-Scale Turbine Vanes Using the Pressure Sensitive Paint Technique
Authors: Ullah Izhar , Wright Lesley M. , Shiau Chao-Cheng , Han Je-Chin , Gao Zhihong , Stanton Andrea
Published: April 2023

This work is an experimental study of film cooling effectiveness on two real-scale turbine vanes in a three-vane annular cascade. The cascade is connected to a high-flow steady compressor to provide the mainstream flow. The inlet velocity is maintained at 35 m/s at the centerline of the annular cascade. Two heavily cooled, real-scale turbine vanes are tested with cooling holes on the pressure (PS) and suction (SS) surfaces. Vane 1 has 645 cooling holes distributed around the vane. Vane 2 has an additional two rows of holes at the near leading edge SS of the vane. The mass flow ratio (MFR) is varied from 3.12% to 4.82%. Increasing the MFR increases film effectiveness. The introduction of additional rows of cooling holes resulted in the re-distribution of coolant from the pressure surface to the suction surface. The re-distribution of coolant is primarily due to the additional coolant supplied to the suction surface for vane 2. This study provides designers with more insight into how to place rows of cooling holes to have improved effectiveness.
Vapor-phase grafting of functional silanes on atomic layer deposited Al2O3
Authors: Rozyyev Vepa , Shevate Rahul , Pathak Rajesh , Murphy Julia G. , Mane Anil U. , Sibener S. J. , Elam Jeffrey W.
Published: April 2023

Fundamental studies are needed to advance our understanding of selective adsorption in aqueous environments and develop more effective sorbents and filters for water treatment. Vapor-phase grafting of functional silanes is an effective method to prepare well-defined surfaces to study selective adsorption. In this investigation, we perform vapor phase grafting of five different silane compounds on aluminum oxide (Al2O3) surfaces prepared by atomic layer deposition. These silane compounds have the general formula L3Si–C3H6–X where the ligand, L, controls the reactivity with the hydroxylated Al2O3 surface and the functional moiety, X, dictates the surface properties of the grafted layer. We study the grafting process using in situ Fourier transform infrared spectroscopy and ex situ x-ray photoelectron spectroscopy measurements, and we characterize the surfaces using scanning electron microscopy, atomic force microscopy, and water contact angle measurements. We found that the structure and density of grafted aminosilanes are influenced by their chemical reactivity and steric constraints around the silicon atom as well as by the nature of the anchoring functional groups. Methyl substituted aminosilanes yielded more hydrophobic surfaces with a higher surface density at higher grafting temperatures. Thiol and nitrile terminated silanes were also studied and compared to the aminosilane terminated surfaces. Uniform monolayer coatings were observed for ethoxy-based silanes, but chlorosilanes exhibited nonuniform coatings as verified by atomic force microscopy measurements.
Physical properties of Zn-Sn-N films governed by the Zn/(Zn + Sn) ratio
Authors: Ren JunYan , Liang LingYan , Liu Xiaohan , Cao Hongtao
Published: April 2023

At present, the application of ZnSnN2 as an active layer in optoelectronic devices is dramatically limited due to its high carrier concentration. It is suggested that off-stoichiometry of cations might be a promising cure. In this work, Zn-Sn-N films with 0.60, 0.67, and 0.85 Zn/(Zn + Sn) ratios were, respectively, fabricated by DC magnetron sputtering. In spite of off-stoichiometry, the films all exhibited a cation-disordered wurtzitelike ZnSnN2 dominated phase except that the crystallinity was decreased with an increasing Zn/(Zn + Sn) ratio. In agreement with the cation-disordered structure, all the Zn-Sn-N films illustrated Raman spectra of a phonon-glasslike characteristic. The refractive index of the films was increased with the Zn/(Zn + Sn) ratio over a wide wavelength range, for example, from 1.990 to 2.459 at the wavelength of 500 nm. The direct optical bandgap of the films varied from 1.36 to 1.68 eV. Most strikingly, an electron concentration of magnitude down to 1016 cm−3 and a very low resistivity down to 10−2 Ω cm were reached for 0.67 and 0.85 Zn/(Zn + Sn) films, respectively. It is highly desirable that both semiconducting and conducting characteristics can be achieved in the Zn-Sn-N material system, which is highly beneficial to its applications in various optoelectronic devices.
Secondary ion mass spectrometry quantification: Do you remember when a factor of 2 was good enough?
Authors: Magee Charles W. , Buyuklimanli Temel H.
Published: April 2023

Well, do you remember when a factor of 2 was good enough? Probably, not unless you have been around secondary ion mass spectrometry (SIMS) since the early 1960s, like one of us has been. This paper will give many references back to the early days of quantification when a local thermal equilibrium model was used to obtain the first results that were accurate to within a factor of 2, but only 60% of the time. It only worked for bulk silicate matrixes. People were not even using SIMS on semiconductors in those days. Several early references showing profiles of ion implants in Si will be referenced, but it was not until 1980 that the first paper was published that explicitly showed how to use ion implants as SIMS standards. People were using ion implants as standards before 1980, but only in limited cases, and with no formal published equations specifying how to use them. But, the samples for which ion implants were used as standards were for dilute concentrations in a single matrix, which had a uniform matrix composition with depth. The rest of the paper will show how we at Eurofins EAG Laboratories tackled the problem of quantification of both major and minor elements in nonuniform, multi-element matrices with continuously graded composition changes using point-by-point CORrected-SIMS. These include SiGe heterostructure bipolar transistors, AlGaAs vertical cavity surface emitting lasers, and B plasma-implanted poly-silicon gates.
Real-time monitoring of atomic layer etching in Cl2/Ar pulsed gas, pulsed power plasmas by optical emission spectroscopy
Authors: Hao Qinzhen , Kim Pilbum , Nam Sang Ki , Kang Song-Yun , Donnelly Vincent M.
Published: April 2023

Optical emission spectroscopy was used as a real-time monitor of the atomic layer etching (ALE) of Si in an Ar inductively coupled plasma (ICP). Pulses of Cl2 gas were repetitively injected into a continuous flow of Ar, followed by the ignition of the ICP and the application of substrate rf bias power (either continuous or rapidly modulated). Optical emissions from Si, SiCl, SiCl2, Ar, and Cl were monitored along a line parallel and close to the substrate surface as a function of time during the bias period, as well as in the ICP without bias power. From an analysis of the time dependencies of the decays of emissions during the modulated bias periods, it is argued that emissions at high Ar carrier gas flow rates are mainly from the primary products sputtered by the energetic Ar ions. Products decay with different, non-exponential time signatures. Cl and SiCl2 emissions decay to nearly undetectable levels toward the end of the bias period. SiCl emission follows a decay profile between that of Si and SiCl2. The time-integrated SiCl2 emission intensity scales linearly with time and correlates with etching rates measured by laser interferometry. The amount of Si etched per ALE cycle and the degree of self-limiting evolution of etching products is a sensitive function of the timing between the initiation and termination of Cl2 flow into the reactor and the application of ICP power. Spatially resolved optical emission is shown to be a useful in situ diagnosis, providing mechanistic insights, as well as process optimization for plasma-assisted atomic layer etching. It is also shown that the emission bands between 360 and 400 nm that are commonly observed during Si etching in a chlorine-containing plasma and are often ascribed to SiCl3 or SiCl3+ are instead most likely the A2Σ → X2Πr system of SiCl.
An approach to constructing prosodic grammar for Mandarin read speech
Authors: Hong Yu-Siang , Chiang Chen-Yu , Wang Yih-Ru , Chen Sin-Horng
Published: April 2023

A data-driven approach to constructing a prosodic grammar of Mandarin read speech is proposed. Prosodic labeling is performed, first, on a large speech corpus with syntactic-tree parsing to add four-level break indices. Two types of prosodic grammatical rules are explored. One type is composed of simplified rules to compute break-type distributions at critical junctures for 5 phrase-level and 11 basic syntactic patterns. The other type entails detailed rules to compute break-type distributions conditioned on syntactic function for four determinative–measure (DM)-related syntactic patterns. Effectiveness of the approach was confirmed by meaningful interpretations of the resulting main prosodic patterns and outliers of targeted syntactic patterns by inferred rules. The main findings are given below. Strong paused breaks are found at VE–clause object (VE, active verb with a sentential object) junctures and junctures after idioms. For DM-related patterns, the entropies of break-type distributions decrease significantly as syntactic functions are involved; break-type distributions on both edges are seriously affected by their syntactic functions; when acting as subject (S) and object (O), their prosodic phenomena support the tendency of Mandarin to be S(VO) (V, verb); strong paused breaks at postboundaries of DM-2–DM-4 are caused by their more complex syntactic structures and greater lengths; and the insertions of modifier + DE (special tag for the word DE) into DM–N (N, noun) junctures cause more paused-break insertions at junctures after DMs.
Comparison of visual and passive acoustic estimates of beaked whale density off El Hierro, Canary Islands
Authors: Arranz P. , Miranda D. , Gkikopoulou K. C. , Cardona A. , Alcazar J. , Aguilar de Soto N. , Thomas L. , Marques T. A.
Published: April 2023

Passive acoustic monitoring (PAM) offers considerable potential for density estimation of cryptic cetaceans, such as beaked whales. However, comparative studies on the accuracy of PAM density estimates from these species are lacking. Concurrent, low-cost drifting PAM, with SoundTraps suspended at 200 m depth, and land-based sightings, were conducted off the Canary Islands. Beaked whale density was estimated using a cue-count method, with click production rate and the probability of click detection derived from digital acoustic recording tags (DTags), and distance sampling techniques, adapted to fixed-point visual surveys. Of 32 870 detections obtained throughout 206 h of PAM recordings, 68% were classified as “certain” beaked whale clicks. Acoustic detection probability was 0.15 [coefficient variation (CV) 0.24] and click production rate was 0.46 clicks s − 1 (CV 0.05). PAM density estimates were in the range of 21.5 or 48.6 whales per 1000 km2 [CV 0.50 or 0.44, 95% confidence interval (CI) 20.7–22.4 or 47–50.9), depending on whether “uncertain” clicks were considered. Density estimates from concurrent sightings resulted in 33.7 whales per 1000 km2 (CV 0.77, 95% CI 8.9–50.5). Cue-count PAM methods under application provide reliable estimates of beaked whale density, over relatively long time periods and in realistic scenarios, as these match the concurrent density estimates obtained from visual observations.
Study on acoustic radiation force of a rigid sphere arbitrarily positioned in a zero-order Mathieu beam
Authors: Li Shuyuan , Zhang Xiaofeng
Published: April 2023

The expressions of the axial and transverse acoustic radiation forces of a rigid sphere arbitrarily positioned in a zero-order Mathieu beam are derived in this paper. The expansion coefficients of the off-axis zero-order Mathieu beam are obtained using the addition theorem of the Bessel functions, and numerical experiments are conducted to verify the theory. The three-dimensional acoustic radiation forces on a rigid sphere are studied when the beam is set at different ellipticity parameters, half-cone angles, and offsets of the incident wave relative to the particle center. Simulation results show that the axial acoustic radiation forces of the rigid sphere are always positive, but the transverse forces vary with the positions of the particle and the beam parameters. Also, by changing the frequency, half-cone angle, and offset of the zero-order Mathieu beam, the value and direction of the transverse forces can be adjusted, which has applications in controlling the rigid sphere to be close to or away from the beam axis. Furthermore, the finite element model is set up to verify the theoretical model, and the results obtained by the two methods are in good agreement. This work may contribute to a better understanding of the underlying mechanisms of the particle manipulation with different acoustic beams.
Experimental study of instantaneous sound intensities in rectangular enclosures
Authors: Tay Daniel , Xiang Ning
Published: April 2023

Instantaneous and time-averaged intensities are relevant field quantities in architectural acoustics investigations. Modeling of intensity flows in coupled volumes and the effect of absorptive material on its trajectory in reverberation chambers have been studied recently. This work focuses on vortical energy flows with a derivation of instantaneous intensity in enclosed spaces and an experimental effort for investigating the changes over time in all field quantities of interest—instantaneous intensity, pressure, and velocity simultaneously. In this study, the scale modeling technique is applied to investigate instantaneous intensity flows experimentally measured using pressure-3D velocity sensors in a rectangular room. Experimental results suggest the presence of vortical intensity modes at specific frequencies correlated to the room dimensions. The resulting simulation of intensity vortices has potential applications in the acoustical design and analysis of complex room geometries where sound energy flows play a major role in the acoustics of the space such as that of coupled-volume spaces and small rooms for critical listening.
Focused ultrasound in the human brain: Current and emerging applications
Authors: Lipsman Nir
Published: April 2023

MR-guided Focused ultrasound (MRgFUS) is a disruptive medical technology, and its implementation in the clinic represents the culmination of decades of research. Lying at the convergence of physics, engineering, imaging, biology and neuroscience, FUS offers the ability to non-invasively and precisely intervene in key circuits that drive common and challenging brain conditions. The actions of FUS in the brain take many forms, ranging from transient blood-brain barrier opening to permanent thermoablation, among other mechanisms. The last decade has seen a dramatic expansion of indications for and experience with FUS in humans, with a resultant exponential increase in academic and public interest in the technology. Applications now span the clinical spectrum in neurological and psychiatric diseases, with insights still emerging from preclinical models and human trials. This presentation provides an overview of clinical trials at various stages of developing using FUS and describes the potential impact, and future directions, of FUS on the landscape of brain therapies.
Office-based kidney stone management with new ultrasound technologies
Authors: Maxwell Adam D. , Kreider Wayne , Wang Yak-Nam , Cunitz Bryan W. , Dunmire Barbrina , Thiel Jeff , Bailey Michael R.
Published: April 2023

Despite the growing incidence of urinary stones, the fundamental interventions for urinary stones have remained the same for several decades. However, technical innovations in ultrasound have enabled new strategies for stone management. Our team aims to employ these methods to establish a new paradigm to treat stones in an office or clinic rather than a surgical suite. Technologies include new imaging methods to detect and characterize stones, burst wave lithotripsy to fragment stones using focused ultrasound rather than shock waves, and ultrasonic propulsion to promote clearance of fragments, all using a single ultrasound platform. This presentation will describe the principles and development of these technologies, as well as the fruitful partnerships between teams of basic scientists, engineers, physicians, and industry that have enabled rapid development of these concepts to successful clinical trials. [Work supported by NIDDK P01 DK043881 and the Focused Ultrasound Foundation.]
Treatment of breast cancer with focused ultrasound: Opportunities and challenges
Authors: Payne Allison
Published: April 2023

Improved early detection methods and treatments have led to the reduction of breast cancer mortality, yet there remains a need for more conservative, more efficacious and less invasive breast cancer treatments. Focused ultrasound (FUS) is a promising non-invasive treatment for localized breast cancer. Magnetic resonance guided FUS leverages breast magnetic resonance imaging (MRI) to plan, monitor and assess treatments under MRI guidance to attain tumor destruction with focused ultrasound, achieving excellent cosmetic, therapeutic, and safety results. MRgFUS is one of the most attractive emerging minimally invasive procedures for breast cancer. This talk will present different focused ultrasound mechanisms that can be used to treat breast cancer and discuss the design considerations that must be considered when developing transducers, sonication protocols and imaging techniques for the treatment of breast cancer with therapeutic ultrasound. Preliminary results from ongoing breast cancer MRgFUS clinical trials will be presented and future opportunities and ongoing challenges for this exciting technology will be elucidated.
Fully electronically steerable high power ultrasound phased arrays for therapy—A review of progress
Authors: Hynynen Kullervo
Published: April 2023

When combined with imaging-guidance focused ultrasound (FUS) provides means for localized delivery of mechanical energy deep into tissues. This focal energy deposition can modify tissue function via thermal or mechanical interactions with the tissue. Traditionally, ultrasound has been focused using spherically curved phased arrays that allow limited electronic steering around geometric focus of the array. To have a fully electronically steered arrays requires the transducer element size to be < wavelength/2 of the ultrasound wave. One way to accomplish this is to use sparse arrays with small transducer elements, the other is to have fully populated arrays with thousands of elements and required electronic complexity. However, the electrical impedance of small transducer elements is high and their efficiency is low and it has been difficult to manufacture arrays with adequate acoustic power. In this talk we will describe how these challenges can be solved with novel manufacturing methods and how we developed complete image-guided systems for both animal and clinical testing. We will also describe our experience with these systems for both brain and body treatments.
Cardioprotective efficacy of ultrasound-targeted nitrofatty acid microbubbles in rat myocardial ischemia-reperfusion injury model
Authors: Amjad Muhammad Wahab , Mohammed Soheb Anwar , Fazzari Marco , Chen Xucai , Freeman Bruce , Matsunaga Terry , Pacella John J.
Published: April 2023

Over 1 million Americans suffer from acute myocardial infarction (AMI) annually. Although mortality from AMI has decreased, post-AMI congestive heart failure is increasing due to microvascular obstruction (MVO). MVO comprises mechanical obstruction, along with oxidate stress and inflammation. Currently available treatments for MVO are not consistently effective. Hence, we have been developing ultrasound (US)-targeted microbubble cavitation (UTMC) as a potential treatment for MVO. Nitro-fatty acids (NFA) are pleiotropic signaling molecules with broad anti-inflammatory actions, potentially beneficial for the treatment of MVO. NFA are amphipathic thus can seamlessly integrate into the phospholipid shell of MBs. Thus, we have constructed microbubbles with NFA (NFABs) to treat ischemia-reperfusion injury (IRI) with UTMC in the rat myocardial model. Left anterior descending (LAD) coronary artery was ligated for 30 min, allowing for IRI. After 15 min of reperfusion, UTMC + NFABs therapy was administered. Echocardiography measurements were recorded at baseline, during ligation and post-treatment. Left ventricular fractional shortening (%) was calculated and NFA concentration in cardiac tissue was determined. UTMC with NFABs exhibited promising efficacy in improving fractional shortening post IRI, and in targeted myocardial delivery of NFA. Studies assessing ejection fraction, myocardial area at risk, histopathology, inflammatory burden, oxidative stress and cytoprotective biomarkers are underway.
Design and fabrication of an acoustic tweezer system for kidney stone manipulation
Authors: Ghanem Mohamed A. , Maxwell Adam D. , Kuznetsova Ekaterina , Bailey Michael R.
Published: April 2023

Acoustic radiation forces can surround and trap objects to manipulate them in three dimensions. It has been demonstrated that the radiation forces can maneuver solid heavy objects similar to kidney stones in live animals under safe acoustic exposure levels. However, initial experiments identified limitations on the steering range of objects because of the array design, and tissue aberrations. Here, we present a method to design an in-house 256 multi-element array to improve the steering range of 2–5 mm stones. We modeled the acoustic field for various geometrical parameters including the element size, transducer focusing, and F-number at a frequency range from 0.5 to 1 MHz. The parameters were then used to simulate the trapping radiation forces on stone models to finalize the design of the array. The array was fabricated with a center frequency of 950 kHz and a focal distance located at 120 mm and an F-number of 1.5. A holography scan was performed to characterize the transducer output. Various trapping beams were measured and compared to simulations. The resulting radiation forces produced were on the order of the weight of the trapped 2-5 mm stone models. [Work supported by NIH P01-DK043881, K25-132416, and Applied Physics Laboratory SEED fellowship.]
Sixty years of contributions to the world of microphones
Authors: West James E. , McLane Ian M. , Rennoll Valerie
Published: April 2023

For almost 60 years, electret microphones have been the preferred sensors for applications in communications, mainly because the microphones are linear over a broad frequency range and rather simple to manufacture. Because the electret microphone can be mass produced with only slight differences in phase and frequency response, multiple units can be combined to form a variety of directional arrays ranging from second-order unidirectional to two-dimensional arrays for focusing on a specific area. While electret microphones and arrays have similar utility for monitoring lung and heart sounds from the body, the body sounds captured can be easily corrupted by noise external to the body. Advanced signal processing techniques can mitigate contributions from airborne noise but are computationally intensive. By modifying the acoustic impedance of the electret microphone’s diaphragm to match that of the body, we are able to capture high-fidelity heart and lung sounds without corruption from airborne noise. This redesign of the original electret microphone could provide a method to continuously monitor lung and heart sounds from a subject regardless of their surrounding noise environment.
Formant-harmonic interactions and vowel perception
Authors: Chan May Pik Yu , Kuang Jianjing
Published: April 2023

The technique of “turning over” in singing which causes perceivable vowel quality shifts has been attributed to the crossing over of H2 over F1. The present work seeks to validate these perceptual claims. A modified AXB discrimination task was completed by 63 speakers, consisting of Klatt synthesized vowels. Versions of the vowels (/i, u, ɑ, ɔ/) varying in the F1 (+/50 Hz) dimension, the F2 (+/−100 Hz) dimension or both F1 and F2 dimensions were used as reference “A/B” tokens, while the “X” token varied along 9 semitones in an F0 continuum. F1 of the vowel aligned to H2 at step 5 of the F0 continuum. Listeners judged whether the vowel quality of token ‘X’ (F0 modified) was closer to “A” or “B” (F1/F2 modified). Results find that listeners perceive the vowel to have a lower F1 during H2-F1 crossover, but the vowel height is perceived to be lower before and after the alignment. This pattern was more robust in the vowel height than the vowel backness dimension, with similar results across vowels. These findings were confirmed with logistic regression models. We conclude that formant harmonic crossovers have psychoacoustic effects on vowel perception, holding implications in vowel modification in singing.
Singing in different performance spaces: Associations between room acoustic and singers perception
Authors: Bottalico Pasquale , Gonzales Redman Yvonne , Glasner Joshua D. , D'Orazio Dario
Published: April 2023

While the acoustic design of concert halls and other performance venues has evolved over time, the fact remains that the acoustic environments are generally designed for the benefit of the listening audiences rather than that of the performers. However, singers adapt their voice to room acoustics. This paper expands upon our current understanding of how a room’s acoustic environment influences a singer’s performance from the perceptions, observations, and lived experiences of performers. The subjects were nine classically-trained singers. Subjects sang the same aria in five different performance venues. After the performance, the singers filled out a questionnaire. Questions were subdivided into five major sections that were designed to capture their perceptions of (1) overall impressions; (2) background noise levels; (3) voice support; (4) Voice clarity. It was observed the overall impression of the room was mostly correlated with STv and IACClate. The perception of reverberation and the noisiness were correlated with C80 and EDT. The perceived voice support and clarity were mostly correlated with STv. This finding indicates the importance of auditory feedback in singers’ performance and the need for an acoustical design that takes into account the performers perception.
Challenges in post-construction sound monitoring for rural wind projects
Authors: Kaliski Ken
Published: April 2023

Postconstruction sound monitoring for rural wind projects has unique challenges. While background sound levels tend to be lower than more urban areas, the sound levels from the wind turbines also tend to be lower, making signal to noise ratios rather low. Thus, differentiating wind turbine sound with wind-induced sound can be difficult, especially when wind speeds are variable. Other issues include safety, wildlife, harsh weather conditions, access to remote sites, difficult protocols, and noise contamination. These issues will be discussed in the context of several recent postconstruction sound monitoring campaigns. Each campaign uses wind turbine shutdowns to measure adjacent background sound levels so that turbine-only sound levels can be calculated. Advantages and disadvantages of the wind turbine shutdown method will be discussed and compared with other methods that don’t require wind turbine shutdowns, such measuring under high wind shear conditions (low ground wind speeds and high hub-height wind speeds), proxy locations, and wind speed binning.
Predicting vehicle category using psychoacoustic indicators from road traffic pass-by noise
Authors: Barros Ablenya , Geluykens Michiel , Pereira Frederico , Goubert Luc , Freitas Elisabete , Vuye Cedric
Published: April 2023

A set of road traffic pass-by noises containing more than 2000 vehicles was recorded following the Statistical Pass-By (SPB) methodology (ISO 11819-1:2022). Besides the acoustic descriptors, psychoacoustic indicators (loudness, sharpness, roughness, fluctuation strength) were retrieved for each pass-by of the three vehicle categories defined in the standard (passenger cars, dual-axles and multi-axles heavy vehicles). A fourth vehicle category, comprised of delivery vans, was also investigated. All psychoacoustic indicators significantly differed among vehicle categories, meaning that not only intensity descriptors but also temporal and spectral features of pass-by noise distinguish those classes. With enough instances and a balanced dataset across groups, a machine-learning classification algorithm was trained with 70% of the dataset to predict vehicle categories using the psychoacoustic indicators. Classification accuracy on the test set reached 72.5%. Accuracy losses were primarily caused by 25% of the actual passenger cars being misclassified as vans and vice-versa. Pooling these two categories increased accuracy to 82%. With more descriptors from road traffic pass-by noise than uniquely its maximum noise level, limiting definitions of vehicle categories may be overcome. As a result, measurements such as the SPB can become broader and vehicle fleets worldwide more consistently represented in terms of noise perception.
The ideal observer: The forgotten second half of signal detection theory
Authors: Lutfi Robert A.
Published: April 2023

In his seminal text “Signal Detection Theory and Psychophysics” (1966), coauthored with John Swets, Dave Green identifies two parts to the theory. The first entails the psychophysical methodology and procedures required to separate sensory and decision processes in detection, the second compares human performance to that of a theoretical ideal observer that optimizes decisions based on the statistical properties of signals and the demands of the detection task. The first part has received far wider application in psychophysics, but there are demonstrable advantages to applying both. In this talk I will give examples from work in our lab where the analysis of ideal observers framed in the methodology has been used to (1) give mathematical meaning to the constructs of stimulus uncertainty and similarity in informational masking; (2) determine sensory constraints on the use of invariant acoustic cues in sound source identification; and (3) isolate a fixed effect of listeners in multi-talker speech segregation across experiments involving vastly different stimuli and psychophysical tasks. [Work supported by NIDCD grant R01 DC001262.]
David Green and the auditory demonstration tapes
Authors: Hartmann William
Published: April 2023

In 1976, Dave Green received a grant from the National Science Foundation to create a series of auditory demonstrations, intended for use in experimental psychology courses or labs. He assembled a group of collaborators from the Harvard Laboratory of Psychophysics and elsewhere that ultimately created a set of ten cassette tapes with 20 demonstrations. Demonstrations included critical band, asymmetry of masking, binaural beats, temporal integration, categorical speech perception, combination tones, Shepard tones, and periodicity pitch among others. The demonstrations were well chosen to cope with the limitations of the cassette medium. Ten years later, cassette tapes had been replaced by compact discs, and the Eindhoven group with Houtsma, Rossing, and Wegenaars created a similar set of digital demonstrations. Those recordings are now available from the Acoustical Society of America as the “Auditory Demonstrations IPO-NIU-ASA” CD. This talk will compare those two sets of recorded demonstrations and indicate the influence that the Harvard tapes had on the ASA CDs, what was kept, what was changed, what was improved, and what was not.
David Green as a mentor: Recollections from his last Ph.D. student
Authors: Lee Jungmee
Published: April 2023

David Green’s significant contributions to psychoacoustics were already widely recognized when I began as his Ph.D. student. At that time, I was new to this country and had little idea of how really huge his presence was in the field. Working with him was at first difficult, he could be quite intimidating. But slowly, as my training progressed, I began to realize how very lucky I was to be his student. Our relationship continued well after my Ph.D. up until he passed away. I want to share my many memorable stories about him as a lifetime mentor and friend.
Contactless manipulation of subwavelength-structured acoustic metasurfaces
Authors: Keller Samuel , Stein Matthew , Luo Yujie , Ilic Ognjen
Published: April 2023

The use of acoustic waves to actuate materials without physical contact is relevant in a variety of fields, including assembly, imaging, and holography. Current acoustic manipulation techniques can produce high-precision, non-invasive and non-contact forces, but they are generally limited to small (subwavelength) objects due to the nature of acoustic trapping potentials. In this study, we describe an approach for overcoming these limitations by using metasurfaces to control the refraction of sound waves. We present theory, simulations, and experimental results showing how a deliberately engineered metasurface can steer the momentum of sound waves and therefore control the intensity and the direction of acoustic radiation pressure. To illustrate the potential applications of this concept, we demonstrate acoustic metasurfaces which exhibit dynamical phenomena such as self-guidance and contactless acoustic pulling. We expand this analysis to survey how this concept can be implemented in different metasurface unit cell topologies and how it scales with different acoustic frequencies. Our results combine actuation with acoustic metamaterial physics to provide novel degrees of freedom to control acoustic forces beyond the limits of traditional wave-matter interactions. Nat. Commun. 13, 6533 (2022).
Source-driven homogenization theory for electro-momentum coupled scatterers
Authors: Gokani Chirag A. , Wallen Samuel P. , Hamilton Mark F. , Haberman Michael R.
Published: April 2023

Willis materials are metamaterials whose subwavelength asymmetry couples the macroscopic pressure-strain and momentum-velocity relations. Recently, the design space of these metamaterials has been expanded to consider asymmetric piezoelectric scatterers and thereby couple the electric field-electric displacement relation to the constitutive equations in the Willis form. The existence of this so-called electro-momentum coupling was first predicted using dynamic homogenization of heterogeneous piezoelectric media [J. Mech. Phys. Solids 134, 103770 (2020)] but it can also be understood through a generalized polarizability tensor α that calculates the electro-acoustic field scattered from a single asymmetric piezoelectric inhomogeneity as a function of local fields [Proc. Mtgs. Acoust. 46, 065002 (2022)]. We present a multiple-scattering dynamic homogenization method that extends the work of Sieck et al. [Phys. Rev. B 96, 104303 (2017)] using the generalized polarizability tensor. The model considers the microscale scattered pressure, velocity, and electric fields in a one-dimensional periodic lattice of identical scatterers to find analytical expressions for the effective macroscale fields. The macroscale fields are then used to find the effective electro-momentum coupling constants in terms of the polarizability of the individual scatterers and the concentration of scatterers in a background medium. [Work supported by DARPA and ARL:UT McKinney Fellowship in Acoustics.]
Bandstructure of phononic crystal of rotating heterogeneous cylinders: Time periodicity due to pure mechanical modulation
Authors: Shymkiv Dmitrii , Li Matthew , Krokhin Arkadii
Published: April 2023

Existing designs of elastic spatiotemporal periodic structures usually require electric/piezoelectric elements that provide temporal modulation of elastic properties. While this method has advantages in many aspects, it usually allows relatively low modulation depth. Here we propose a design for spatiotemporal elastic media that is experimentally feasible, involves pure mechanical elements, and may provide any desired temporal modulation depth. In our scheme the scatterers of a phononic crystal are cylinders composed of two (or more) semi-cylinders (parts) of different materials. The cylinders are capable for rotation with high speed in a stationary fluid environment that provides time-dependent medium for propagating sound wave. Adjusting the elastic contrast between the materials of solid semi-cylinders the necessary modulation depths can be achieved. Different regimes of temporal modulation, from adiabatic to rapid oscillations can be realized by varying the frequency of rotation. We report momentum/energy gaps and other features of the bandstructure that are theoretically obtained using plane wave expansion. Nonreciprocal effects are studied for a phononic crystal with a square unit cell containing two heterogeneous cylinders rotating synchronically with a constant phase shift. [This work is supported by the NSF under EFRI Grant No. 1741677.]
Audio-visual clear speech: Articulation, acoustics and perception of segments and tones
Authors: Wang Yue , Jongman Allard , Sereno Joan
Published: April 2023

Research has established that clear speech with enhanced acoustic signal benefits segmental intelligibility. Less attention has been paid to visible articulatory correlates of clear-speech modifications, or to clear-speech effects at the suprasegmental level (e.g., lexical tone). Questions thus arise as to the extent to which clear-speech cues are beneficial in different input modalities and linguistic domains, and how different resources are incorporated. These questions address the fundamental argument in clear-speech research with respect to the trade-off between effects of signal-based phoneme-extrinsic modifications to strengthen overall acoustic salience versus code-based phoneme-specific modifications to maintain phonemic distinctions. In this talk, we report findings from our studies on audio-visual clear speech production and perception, including vowels and fricatives differing in auditory and visual saliency, and lexical tones believed to lack visual distinctiveness. In a 3-stream study, we use computer-vision techniques to extract visible facial cues associated with segmental and tonal productions in plain and clear speech, characterize distinctive acoustic features across speech styles, and compare audio-visual plain and clear speech perception. Findings are discussed in terms of how speakers and perceivers strike a balance between utilizing general saliency-enhancing and category-specific cues across audio-visual modalities and speech styles with the aim of improving intelligibility.
Clear speech adaptations and effortful speaking and listening in background noise across the lifespan
Authors: Tuomainen Outi , Taschenberger Linda , Rosen Stuart , Hazan Valerie
Published: April 2023

Our study investigates strategies speakers use to clarify their speech and compensate for the impact of background noise in everyday settings. We recorded 114 individuals (8-80 years) while they carried out an interactive problem-solving task (diapix) in quiet, background speech and background non-speech noise. A secondary bell-press task was added to increase cognitive load. We measured (i) articulation rate, median fundamental frequency (f0) and intensity which reflect clear speech adaptations and speaking effort; (ii) subjective ratings of listening effort; and iii) secondary task performance reflecting distractibility (d-prime). Regardless of age, speakers increased their f0 and intensity more in non-speech noise than in quiet or background speech. However, they made more errors in the secondary task and reported greater listening effort when the background noise was speech. Older participants (>50 years) increased speaking effort in both noise types, but younger children (<13 years) increased speaking effort only in background speech. These results indicate that, in terms of speaking effort, background speech (more cognitively demanding) is effortful for children and older adults. However, background noise (more peripheral interference) is mostly effortful for older adults. In terms of listening effort and distractibility, we observed greater interference in background speech regardless of participant age.
Clear speech research in dysarthria
Authors: Stipancic Kaila L. , Tjaden Kris
Published: April 2023

A sizeable group of theoretically grounded studies has defined clear speech production for neurotypical talkers as well as the perceptual consequences of neurotypical clear speech. Although less robust in size compared to the neurotypical literature, clear speech research focused on the clinical population of dysarthria has grown substantially over the last decade. The growth stems, in part, from the positive effects of clear speech on intelligibility, a perceptual construct central to the clinical management of dysarthria. We will review dysarthria research from our lab examining the effects of clear speech on speech acoustics and subsequently, on perceptual measures of speech. Factors which may contribute to variability in clear speech outcomes in dysarthria will be considered. These factors include but are not limited to (1) dysarthria neuropathology; (2) the instructions provided to elicit a clear speaking style; (3) the amount of effort exerted by the speaker; and (4) the choice of measures for evaluating efficacy. Finally, we will offer suggestions for future research that may accelerate translation of clear speech research to clinical practice.
Data-driven morphological component analysis
Authors: Kurdila Hannah , Goehle Geoff , Brown Daniel C.
Published: April 2023

A common goal in signal processing is to decompose a signal into constituent components. Morphological Component Analysis (MCA) is a convex optimization technique that can be used to decompose a signal into a sum of sparse representations determined by chosen dictionaries. Previously, MCA has been shown to successfully decompose sonar data into long-duration and short duration components, using Enveloped Sinusoid Parseval (ESP) frames as the dictionaries. However, in its current state, ESP MCA is model-driven and requires prior selection of envelope parameters. This presentation describes the addition of hyper-parameter tuning to ESP MCA. Specifically, gradient descent is performed on an unrolled version of the ESP MCA regularization algorithm in order to learn the optimal envelope parameters used to construct the ESP frames. Addition of hyper-parameter tuning allows the dictionary atoms to adapt and thus improves sparse representation of the sensed data.
Micro-multipath interference and its effect on sub-minute acoustic fluctuations: Observations of mid-frequency acoustic propagation in the upper ocean
Authors: DeFilippis Jacob P. , Cornuelle Bruce , Lucas Andrew J. , Hodgkiss William , Lenain Luc , Kuperman William , Alford Matthew
Published: April 2023

An experiment was conducted to investigate how variability in the acoustic channel impulse response at signal processing timescales of seconds to minutes is related to internal-wave-driven changes in the ocean sound speed field on timescales of tens of minutes. We find that vertical fine-scale structures (≤10 m) embedded in the sound speed profile have strong second derivatives which allow for the formation of acoustic caustics as well as acoustic propagation pathways that interfere with each other (micro-multipaths). Both effects are sensitive to vertical displacement by internal waves, which can therefore produce sub-minute acoustic fluctuations from internal waves that have timescales longer than a minute.