bluuebunny/crossref_metadata_2025 huggingface dataset:
Rack-Level Thermosyphon Cooling and Vapor-Compression Driven Heat Recovery: Condenser Model
Authors: Khalid Rehan , Amalfi Raffaele Luca , Wemhoff Aaron P.
Published: November 2021

This paper is focused on the modeling of a brazed plate heat exchanger (BPHE) for a novel in-rack cooling loop coupled with heat recovery capability for enhanced thermal management of datacenters. In the proposed technology, the BPHE is acting as a condenser, and the model presented in this study can be applied in either the cooling loop or vapor recompression loop. Thus, the primary fluid enters as either superheated (in the vapor recompression loop) or saturated vapor (in the cooling loop), while the secondary fluid enters as a sub-cooled liquid. The model augments an existing technique from the open literature and is applied to condensation of a low-pressure refrigerant R245fa. The model assumes a two-fluid heat exchanger with R245fa and water as the primary and secondary fluids, respectively, flowing in counterflow configuration; however, the model can also handle parallel flow configuration. The 2-D model divides the heat exchanger geometry into a discrete number of slices to analyze heat transfer and pressure drops (including static, momentum and frictional losses) of both fluids, which are used to predict the exit temperature and pressure of both fluids. The model predicts the exchanger duty based on the local energy balance. The predicted values of fluid output properties (secondary fluid temperature and pressure, and primary fluid vapor quality and pressure) along with heat exchanger duty show good agreement when compared against a commercial software.
Effect of Aging on the Properties of Intermetallic Layers in SAC+Bi Solder Joints
Authors: Haq Mohammad Ashraful , Hoque Mohd Aminul , Suhling Jeffrey C. , Lall Pradeep
Published: November 2021

A major problem faced by electronic packaging industries is the poor reliability of lead free solder joints. One of the most common methods utilized to tackle this problem is by doping the alloy with other elements, especially bismuth. Researches have shown Bismuth doped solder joints to mostly fail near the Intermetallic (IMC) layer rather than the bulk of the solder joint as commonly observed in traditional SAC305 solder joints. An understanding of the properties of this IMC layer would thus provide better solutions on improving the reliability of bismuth doped solder joints. In this study, the authors have used three different lead free solders doped with 1%, 2% and 3% bismuth. Joints of these alloys were created on copper substrates. The joints were then polished to clearly expose the IMC layers. These joints were then aged at 125 °C for 0, 1, 2, 5 and 10 days. For each aging condition, the elastic modulus and the hardness of the IMC layers were evaluated using a nanoindenter. The IMC layer thickness and the chemical composition of the IMC layers were also determined for each alloy at every aging condition using Scanning Electron Microscopy (SEM) and EDS. The results from this study will give a better idea on how the percentage of bismuth content in lead free solder affects the IMC layer properties and the overall reliability of the solder joints.
Performance Analysis of Micro-Raman Spectroscopy Models for Thermal Conductivity Calculation
Authors: Meydando Taher , Donmezer Nazli
Published: November 2021

Micro-Raman spectroscopy has been preferred recently to measure the thermal conductivity of thin-films due to its nondestructive and non-contact nature. However, the thermal size effects originating from both localized heat generation from Raman laser and phonon scattering at boundaries may cause erroneous estimation of the thermal conductivities with the current approach. In this study, the gray phonon Boltzmann transport equation (BTE) is solved to improve the results of micro-Raman thermal conductivity measurements. Due to the frequency independence of single phonon mode in the gray BTE model, our method stays ahead of most theoretical methods in calculation time while giving adequate agreement with the literature data. The improved thermal conductivities are evaluated at various laser powers and focal lengths. Subsequently, the values of thermal conductivities are compared with a simple slab model in which the deduction of thermal conductivity in sub-micron thicknesses is calculated using reduced heat flux through the slab resulting from phonon directional energy densities. The results show that subsequent errors are present in measuring the thermal conductivity of relatively thick, thin films with this technique which are noticed by comparing with the simple slab model. Finally, a virtual micro-Raman thermography experiment is developed, and its validity is verified by the same slab model.
Lightweight, Cost-Effective Power Modules Using Polymer Baseplates With Integrated Microconvective Cooling
Authors: Earley David , Mizerak Jordan , May Chris , Malouin Bernard
Published: November 2021

The advent of wide bandgap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), has enabled power electronics with increasing current densities and switching frequencies. A byproduct of these improved electrical characteristics is an increase in thermal power density. Indeed, the full capability of WBG semiconductors may be underutilized if the thermal management solution cannot keep pace with the device heat generation density. Further, as many power electronics devices are integrated into a power module form factor containing a metal baseplate to allow heat spreading from high heat fluxes generated at semiconductor dies, system integrators are often sensitive to cost and weight considerations in building up systems with traditional power module designs.

In this paper, a polymer baseplate with integrated microconvective cooling (PBIMC) is designed and built as a low-weight, cost-effective alternative for metal baseplates on power module devices. Microconvective cooling, featuring optimized single-phase impingement cooling and effluent fluid flow control, provides high power density heat removal from localized heat flux areas in power module packages to obviate the need for a metal heat spreader. Thermal performance of the PBIMC is tested on a thermal test vehicle representative of an IGBT power module to power densities up to 200W/cm2 and compared to an off the shelf minichannel cold plate. The PBIMC achieved equivalent per IGBT case-to-fluid areal thermal resistances of 0.15 K-cm2/W, a 69% decrease compared to the baseline cold plate. Additionally, thermal crosstalk was shown to be reduced by up to 89% when moving from the cold plate to the PBIMC, demonstrating potential advantages in utilizing thermal management techniques that do not feature heat spreading. The prototype-level polymer baseplates showed a > 80% decrease in weight compared to a traditional power module metal baseplate. The study concludes that the PBIMC shows promise as a solution for high current density power electronics in weight sensitive applications, while providing opportunities for cost savings.
Printed Flexible LC Filter Using Additive Micro-Dispensing With Silver Conductive Paste and ECA for Component Attachment
Authors: Lall Pradeep , Narangaparambil Jinesh , Schulze Kyle , Miller Scott
Published: November 2021

Filters are used in a variety of signal processing applications in commercial and defense electronics. The use of additively printed electronics in high-frequency applications requires an understanding of the process-performance interactions versus frequency of operation. Assembly of filters for integration into existing circuits requires additively printed metallization traces in addition to component attachment methods. Comparison of frequency response of the additively-printed filtering circuits vs conventional filters subtractively-fabricated on rigid substrates is needed to determine the performance parity of additive fabrication methods. In this paper, a micro-dispensing device is used to print conductive traces and electrically conductive adhesive (ECA) pads for the attachment of components. The effect of different print parameters on the width and height of the trace has been studied. Mechanical and electrical properties also play an important role in the study of different sintering conditions. Optimized parameters from the printing process and sintering analysis are used to print and compare commercially available LC filter circuitry using the Bode plot.
Life-Assessment for Thin Flexible Batteries Under U-Flex-to-Install and Dynamic Folding
Authors: Lall Pradeep , Soni Ved , Miller Scott
Published: November 2021

The growing need for wearable devices, fitness accessories and biomedical equipment has led to the upsurge in research and development of thin flexible battery research and development. The current state of art wearable electronics products being developed in several fields require installation of power sources in different configurations and at times require the battery to undergo mechanical folding during product operation. This requires the product batteries to robustly withstand the imposed mechanical stresses during use along with the other desirable characteristics attributed to the power source such as high C-rate capability, high capacity and low capacity degradation rate. Works that explore the effects of static and dynamic folding on li-ion power sources is limited and oftentimes doesn’t adhere to definite test protocols resulting in non-standardized experimental data that can’t be applied to real-life product scenarios. Specifically, the effect of fold diameter on the battery state of health degradation when subjected to both static and dynamic folding is not yet completely explored. Present study aims to address this gap in the literature by investigating the effect of varying the fold diameter is both static (U-flex-to-install) and dynamic (dynamic U-fold) tests. Four different values of fold diameters have been chosen for experimentation and to study its effect during the aforementioned tests. Multiple samples have been tested for a given test condition so as to generate high fidelity data. Ultimately, a regression model developed previously has been augmented with the results generated in the current study.
Thermal Transport Across Al-(AlxGa1-x)2O3 and Al-Ga2O3 Interfaces
Authors: Shi Jingjing , Krishnan Anusha , Bhuiyan A. F. M. Anhar Uddin , Koh Yee Rui , Huynh Kenny , Mauze Akhil , Mu Sai , Foley Brian M. , Ahmad Habib , Itoh Takeki , Zhang Yuewei , Yuan Chao , Kim Samuel , Doolittle W. Alan , Van de Walle Chris , Speck James S. , Goorsky Mark , Hopkins Patrick , Zhao Hongping , Graham Samuel
Published: November 2021

(AlxGa1−x)2O3 and Ga2O3 are promising wide bandgap semiconductors for application in power electronics and radio frequency devices because of their exceptional electrical transport properties. However, the heat dissipation in these devices will be limited by the ultra-low thermal conductivity of (AlxGa1−x)2O3 and Ga2O3. Previous studies showed that these devices could achieve high power density with double-sided or top-side cooling strategies. Therefore, the thermal transport across metal-(AlxGa1−x)2O3 and metal-Ga2O3 contacts is important, since heat will be conducted through the metal-semiconductor interface as a preferred pathway to extract heat from the devices. In this work, we study the thermal transport across Al-(AlxGa1−x)2O3 and Al-Ga2O3 interfaces with an (010) orientation for the semiconductors. We have applied thermal and material characterization (time-domain thermoreflectance (TDTR) and high-resolution transmission electron microscopy (HRTEM) together with theoretical approaches to understand the interfacial thermal transport at Al-(AlxGa1−x)2O3 and AlGa2O3 contacts. It is found that for different growth methods, the highest TBC at Al-Ga2O3 interface occurs with molecular beam epitaxy (MBE) deposition of the Al on Ga2O3. However, the experimentally measured TBC at E-beam evaporated Al interfaces is much lower than that at the MBE grown Al interfaces. The measured values are also much lower than theoretical predictions, and it is related to the interfacial chemical reactions that occur at the interfaces. The effect of Al composition on interfacial thermal transport at Al/(AlxGa1−x)2O3 interface is also studied. It is found that the TBC at the E-beam evaporated Al/(AlxGa1−x)2O3 interface is very close to that of the E-beam evaporated Al-Ga2O3 interface at different temperatures in the ternary alloy studied.
Multiple source localization using learning-based sparse estimation in deep ocean
Authors: Liu Yining , Niu Haiqiang , Yang Sisi , Li Zhenglin
Published: November 2021

This paper proposes the use of gated feedback gated recurrent unit network (GFGRU), a learning-based sparse estimation algorithm, for multiple source localization in the direct arrival zone of the deep ocean. The GFGRU, trained on sound field replicas of a single source generated by an acoustic propagation model, is used to estimate the ranges and depths of multiple sources without knowing the number of sources. The performance of GFGRU is compared to the Bartlett processor, feedforward neural network (FNN), and sparse Bayesian Learning (SBL) algorithm. Simulations indicate that GFGRU behaves similarly to SBL and offers modest localization performance improvement over the Bartlett and FNN in the presence of array tilt mismatch. The results of real data from the South China Sea also verify the robustness of the proposed GFGRU using a 105 m-aperture vertical array in the deep ocean.
Experimental evaluation of pseudo-sound in a parametric array
Authors: Song Jiyoung , Jung Donghwan , Kim J. S. , Lee Jaehyuk
Published: November 2021

Parametric arrays have been widely investigated due to their high directivity in the low-frequency region when measuring the acoustic characteristics of materials, such as sound transmission and reflection properties, in the limited space of acoustic water tanks. Because a parametric array utilizes nonlinear interaction across the frequency components, nonlinear phenomena arise in both the acoustic medium and the hydrophone system. The unwanted nonlinear sound generated in the hydrophone and instrumentation is termed pseudo-sound. This study devised an experiment to measure the pseudo-sound without a truncator to assess the effect of the pseudo-sound in the near field. In order to separately measure the pseudo-sound, the hydrophone was placed close to the projector so that the pseudo-sound was dominantly generated. The method is based on the fact that, if we can suppress a parametric signal by minimizing the propagation path length in the medium, the resulting measured signal can be attributed to the pseudo-sound. The resultant signal levels were matched to the levels at corresponding distances based on the primary levels of a (separately conducted) distance-varying experiment. Finally, the suitability of the proposed technique was evaluated by comparing its results with the pseudo-sound levels measured using a truncator.
Effects of crosslinking density on the acoustic properties of hydrogel scaffolds
Authors: Anderson Megan , Osborn Jenna , Zhang Lijie Grace , Sarkar Kausik
Published: November 2021

Hydrogels are popular materials for various biomedical applications due to their large water content which resembles that of biological tissues. Given the relevance of hydrogels in therapeutic applications, the non-invasive characterization of hydrogels is highly desirable for in vivo monitoring, whereas traditional testing methods are destructive, ultrasound is a safe and readily available tool that could be used for non-invasive characterization. In the present study, gelatin methacrylate (GelMA) hydrogel scaffolds were produced with a range of crosslinking densities by varying both GelMA concentration and ultraviolet light curing time. These scaffolds were evaluated using pulse-echo ultrasound techniques, resulting in measurements for the speed of sound, acoustic impedance, and attenuation coefficient of each hydrogel. Compression testing was also performed. The stiffness of the hydrogels was found to be between 5 and 235 kPa with an increase in the GelMA concentration or an increase in ultraviolet light curing time corresponding to a stiffer hydrogel. The impact of stiffness and preparation parameters on the acoustic properties of the hydrogels will be discussed. Further knowledge on the effect of crosslinking density on acoustic properties will inform the use of acoustic techniques in characterizing hydrogels.
Three-dimensional echo decorrelation imaging of percutaneous microwave ablation in liver tumors
Authors: Ghahramani Z. Elmira , Grimm Peter D. , Saremi Bahar , Choe Kyuran A. , Chadalavada Seetharam , Makramalla Abouelmagd , Ristagno Ross L. , Zhang Lulu , Mast T. Douglas
Published: November 2021

In a pilot clinical study, patients underwent standard-of-care percutaneous microwave ablation (MWA) of liver tumors with monitoring by three-dimensional (3D) ultrasound echo decorrelation imaging. An MWA needle (Amica) was inserted into each tumor, guided by x-ray computed tomography (CT) and ultrasound imaging. A matrix ultrasound array (4Z1c array with Acuson SC2000 scanner, Siemens) was positioned on patients’ skin near the MWA needle insertion point. Paired sequential complex in-phase/quadrature (IQ) echo volumes (inter-frame time 5–20 ms) were acquired throughout ablation at 10–20 s intervals, then processed to form 3D echo decorrelation images. Respiratory motion was estimated and compensated using a theoretical model that separates motion- and heat-induced echo decorrelation. Volumetric B-mode images constructed from the same IQ data were rigidly registered to follow-up contrast-enhanced magnetic resonance (MR) image volumes, recorded within 4 days after MWA. Specified registration transformations were then applied to cumulative 3D echo decorrelation maps, which were compared voxel-wise to ablation zones segmented from MR images. Receiver operator characteristic (ROC) curve analysis indicated effective prediction of local ablation by motion-compensated echo decorrelation imaging. Comparison with subsequent follow-up MR images tested the ability of 3D echo decorrelation imaging to predict any incomplete treatment or recurrence of treated tumors.
Overview and tutorial on the identification and tracking of pitch and frequency
Authors: Smith Sarah R.
Published: November 2021

Many diverse areas of acoustics leverage the identification and tracking of frequency over time. Pitch tracking plays an important role in music information retrieval and performance analysis. Frequency contours are also important features in speech processing and bioacoustics applications, and the identification of frequency content in a signal is widely used. From a signal processing perspective, these applications vary drastically with respect to signal duration and frequency, desired resolutions, and amount of signal interference. In some cases, a single pitch is used to characterize a multicomponent sound, while other applications demand independent tracking of individual components. As such, a wide variety of algorithms exist in both the time and frequency domains. This presentation provides a general overview of commonly used methods and available implementations for tracking pitch and/or frequency. Potential sources of error will be emphasized, focusing on the considerations relevant to selecting and optimizing an algorithm for a given application.
The effects of face masks on speech-in-speech recognition for children and adults
Authors: Flaherty Mary M. , Arzuaga Briana , Bottalico Pasquale
Published: November 2021

While face masks have been used in medical settings for decades, they have only recently become a part of everyday life due to the COVID-19 pandemic. The implications for how face masks impact speech communication in noise are not well understood, particularly in the pediatric population. Given that previous research has shown that speech recognition in noise is more challenging for children than for adults, it is critical that we examine the effects of face masks on children’s speech understanding in these contexts. The present study explored the effects of different face masks on school-age children’s speech-in-speech recognition. Word recognition was measured in a competing two-talker speech masker. Target words were recorded using a real talker in 5 mask conditions: no mask, surgical, N95, clear plastic, and face shield. Preliminary results indicate that performance was the most negatively impacted when the talker wore a face shield or clear plastic mask. There were no differences between the no-mask condition and either surgical or N95 mask. Acoustic analyses on the target speech were performed to explore causes of these effects. Findings suggest that optimal communication with children may be achieved using surgical or N95 masks as opposed to other mask types.
Some measured frequency domain characteristics of the underwater vector and scalar acoustic field components with applications to communication receivers
Authors: Rashid Rami , Zhang Erjian , Abdi Ali
Published: November 2021

Vector and scalar components of the underwater acoustic field can be used for multichannel signal demodulation [A. Abdi, et al., “A new vector sensor receiver for underwater acoustic communication,” in Proceedings of the Oceans (2007), pp. 1–10; A. Abdi and H. Guo, “A new compact multichannel receiver for underwater wireless communication networks,” IEEE Trans. Wireless Commun. 8, 3326–3329 (2009)]. In frequency domain-based communication methods such as orthogonal frequency division multiplexing (OFDM) using multiple collected signals, understanding the behavior of the channels in frequency domain is important for proper system design. In this paper, we examine the experimental data obtained by transmitting pilot tones for channel estimation, to estimate various channel frequency responses. More specifically, channel frequency responses of the X, Y and Z components of the underwater acoustic vector field are estimated, in addition to the scalar field component channel frequency response. Analysis of the measured frequency responses reveals differences in parameters such as condition numbers and eigenvalues of measured channel matrices. Knowledge of these parameters is needed for designing communication receivers that utilize the vector and scalar components of the acoustic field in frequency domain. [The work is supported in part by NSF, Grant IIP-1500123.]
Signal detection in time spreading underwater environments using vector and scalar sensors
Authors: Rashid Rami , Zhang Erjian , Michalopoulou Zoi-Heleni , Abdi Ali
Published: November 2021

In this paper, we aim to examine the effects of the time-spreading signal distortion caused by multipath propagation in underwater environments, using experimental data. We use the Replica Correlation Integration detector [B. Friedlander and A. Zeira, “Detection of broadband signals in frequency and time dispersive channels,” IEEE Trans. Signal Process. 44(7), 1613–1622 (1996)], which is designed to take the multiple echoes of the transmitted signal into consideration. We apply this detector to measured data collected by underwater acoustic sensors. We use two types of sensors. The first sensor is a hydrophone that measures only the scalar component of the acoustic field, i.e., the acoustic pressure. The second sensor is a vector sensor that simultaneously measures the scalar and the three vector components of the acoustic field, i.e., the three acoustic particle velocity x, y, and z components. This sensor can perform as a multi-channel detector. Analysis of the measured data provides insights into the signal detection capabilities of the vector field components in time-spreading underwater environments. [The work is supported in part by NSF, Grant IIP-1500123, and ONR.]
Estimating sediment interval velocity using a monostatic sonar from a seabed with tilted layers
Authors: Henderson Cody , Holland Charles W.
Published: November 2021

Recently, it has been shown that sediment layer interval velocity can be obtained from a multibeam monostatic sonar. In that work, plane-parallel sediment layering was assumed. Since tilted sediment layers are common in the marine environment, the method is expanded to treat them explicitly. The in- and out-of-plane tilted layers affect the travel times in each layer, which complicates interval velocity estimation. This effect is mitigated by applying a dip moveout correction for each sediment layer. Testing is performed using simulated scattering data from rough, tilted, layered seabeds for dip angles up to a few degrees. The interval velocity estimation method is also applied to at-sea data (acquired by the 2–9 kHz SBP29 multibeam sub-bottom profiler) in areas with tilted layers. [Research supported by ONR Coastal Geosciences]
Acoustic reflection measurements from the bottom of the Challenger Deep
Authors: Lin Ying-Tsong , Vescovo Victor , Macdonald Timothy , von Krusenstiern Kate , Dziak Robert P. , Matsumoto Haru , Meinig Christian
Published: November 2021

An underwater sound propagation experiment was conducted in June 2020 at the Challenger Deep of the Mariana Trench on a scientific expedition cruise sponsored by Caladan Oceanic LLC. The primary objective of the experiment was to study ambient sound and acoustic signal propagation in the hadal zone, the deepest region of the ocean. State-of-the-art equipment was utilized to measure the seafloor bathymetry and water column temperature and salinity profiles. A full-ocean-depth hydrophone (FODH) was mounted on a scientific bottom lander deployed right at the bottom of the Challenger Deep (10 935 ± 6 m deep.) A low-frequency (115 Hz) sound source was towed by the expedition ship at a depth near the sea surface to transmit acoustic signals that were recorded by the FODH. High-fidelity numerical models of sound propagation were employed to aid acoustic data analyses, especially for characterizing the geoacoustic properties of the bottom sediments from the acoustic reflection measurements. [Worked supported by Caladan Oceanic LLC.]
Correlation between the fluctuations of underwater sound propagation and shelfbreak oceanography
Authors: Lin Ying-Tsong , Gawarkiewicz Glen , Lavery Andone C. , Zhang Weifeng G. , Jech J Michael , Siderius Martin , Chaytor Jason , Siegmann William L. , Reeves Ozanich Emma , DeCourcy Brendan J. , Loranger Scott , Forsyth Jacob , Johnson Jennifer , Newhall Arthur E. , Bahr Frank
Published: November 2021

A network of sound sources, hydrophone arrays and physical oceanography and biological survey equipment was established at the southern edge of the New England Shelf in May 2021 to investigate how the oceanic processes at shelfbreak regions affect underwater sound propagation. The ocean processes of particular interest include shelfbreak fronts, shelf water streamers, thermohaline intrusions, and internal waves along with other significant marine geological features and biological factors, such as seafloor slopes, submarine canyons, variable seabed properties, and fish schooling and shoaling. With fixed propagation paths, acoustic fluctuations can be correlated with environmental variations between the network nodes. The temporal scale of the acoustic measurements ranges from minutes to weeks, and the spatial coverage is up to 20–30 km. Adaptive sampling and tracking of acoustic sensitivity “hot spots” was also conducted during the experiment to assist real-time joint ocean acoustics and circulation modeling. This presentation will review the design concept of this ocean acoustic network experiment and provide an overview the preliminary results. [Work supported by the Office of Naval Research.]
New England shelf break acoustic experiment (NESBA): Assimilation of acoustic pressure observations
Authors: Wendeborn Drew , Stevens Bill , Siderius Martin
Published: November 2021

The NESBA Signals and Noise experiment was conducted in April–May 2021. The goal of the experiment is to assess the potential for sonar prediction effectiveness gains given improved environmental awareness. This talk addresses the NESBA sub-goal of demonstrating that acoustic pressure observations could be assimilated into high-resolution ocean models (i.e., Regional NCOM) resulting in lower analysis and forecast errors for both the ocean environment variables and acoustic predictions. The steps involved in this experimental analysis include: (1) measurement of broadband signals received by drifting vertical arrays; (2) generation of empirical orthogonal function (EOF) representations of the local sound speed environment based on NOAA Regional NCOM forecasts; (3) use of acoustic simulation to generate simulated signals for general elements of the EOF state space; and (4) the use of optimization techniques to determine the EOF coefficients that best match each set of acoustic measurements. Multiple optimizations are to be conducted, each resulting in a synthetic CTD measurement at a specific location and time. These synthetic CTDs will be assimilated into Regional NCOM and comparisons will be made between baseline NCOM forecasts, NCOM forecasts including the synthetic CTD data, and CTD measurement data. [Work supported by the Office of Naval Research.]
Evaluating empirical and variational mode decomposition capabilities on Risso’s and Pacific white-sided dolphin pulsed signals in a sparse and noisy dataset
Authors: Seger Kerri D. , Liang Yue , Al-Badrawi Mahdi H. , Foster Christopher , Kirsch Nicholas J.
Published: November 2021

Tracking marine species is critical for conversation efforts, therefore automatic detectors and classifiers play a significant role to facilitate such efforts. Previous work demonstrated the efficacy of the Empirical Mode Decomposition (EMD) classification capabilities in differentiating marine mammal vocalizations. However, EMD failed to separate Risso’s and Pacific white-sided dolphin pulsed signals due to their high spectral similarity and limitations of EMD filtering response. The Variational Mode Decomposition (VMD), a more advanced version of EMD, paired with an automated detector, provided a promising tool to tell such dolphins apart with accuracy up to 81.3% even under severe channel conditions. This level of accuracy on a sparse dataset that does not contain whistles is important for automatically classifying pulsed signals from dolphins that do not whistle, live in noisy environments, and/or are recorded in datasets with low duty cycles. Because many datasets collected to date in the Arctic Ocean are sparse due to conserving battery power over long deployments, the VMD method can help add to our ability to track dolphins using just their pulsed signals as they expand northward with warming waters.
Quantifying acoustic backscatter of seafloor using multibeam echosounder
Authors: Manik Henry
Published: November 2021

Multibeam echosounder is one of the most important technology for carrying out hydrographic surveys, benthic habitat mapping, marine fisheries, and seafloor surveys. The advantage of multibeam echosounder were produced simultaneously bathymetric and acoustic backscatter. The purpose of this research was to process and to analyze multibeam echosounder data for mapping the seafloor and quantifying acoustic backscatter. Bathymetric data was processed used the Combined Uncertainty and Bathymetry Estimator (CUBE) method. The analysis of seabed type used Angular Response Analysis (ARA) and Sediment Analysis Tool (SAT). Seawater depth in the survey area was measured from 11.2 m to 45.3 m. Analysis of seafloor classification consists of clay, silt, sand, and rock bottom. The highest acoustic backscatter was rock bottom and the lowest was clay bottom.
Simultaneous velocity and concentration profiling of nuclear waste suspensions in pipe flow, using ultrasonic Doppler and backscatter analysis
Authors: Hussain Serish T. , Barnes Martyn , Peakall Jeffrey , Hunter Timothy
Published: November 2021

Complex magnox ponds at Sellafield retain hydroxide-based sludge with unknown physicochemical properties. The sludge is a corroded form of magnesium-based fuel cladding used in first generation magnox reactors. Long term storage and open-air aqueous conditions are major contributors to corrosion. Waste needs to be transported to interim storage using engineered pipelines. Remote in situ characterisation of sludge was achieved using a non-invasive ultrasonic velocity profiler (UVP). The UVP uses raw velocity and echo amplitude to extract velocity and acoustic profiles. Profiles are used to understand effect of particle size and concentration on attenuation. Spherical glass particles with two size distributions of known acoustic behaviour were analysed to establish acoustic profiles. 4MHz frequency transducers were mounted in-line on engineered pipelines, 90 deg and 135 deg to flow. Data were extracted from in situ transducers for validation and non-contact probes were utilised to prove data could be collected safely without exposure. Flow rate was varied to ensure full developed flow before analysis. Profiles extracted from concentration arrays were analysed to understand particle segregation in horizontal pipe arrangements and attenuation. Remote in-line characterisation allows safe analysis, whilst in-line characterisation saves time and money. Moving forward, complex non-defined nuclear simulants will be analysed to investigate the UVP's limitations.
The successful application of acoustic lighting in restaurants
Authors: Belanger Zackery
Published: November 2021

Contemporary restaurants suffer from acoustic deficiencies for myriad reasons, including minimal visual design, a prevalence of cleanable and durable surfaces, low room volume, high patron densities, the perceived cost of acoustic absorption, the late realization that a problem exists (after opening), lack of confidence in the effectiveness of proposed solutions, and the potential negative impact on visual aesthetics. Acoustic lighting is a new sector of the acoustic product market that shows potential in alleviating some of these problems. In this study, the basics of acoustic lighting history, design, and implementation are introduced, and the benefits and drawbacks of acoustic lighting are covered. Two case studies will be presented with measured data—a restaurant and a tap room—which are both located in Seattle. Finally, the potential future of acoustic lighting will be anticipated as this new approach solidifies in acoustic architecture.
Acoustics in the culture of context
Authors: Altoon Ronald A.
Published: November 2021

Not being an acoustician, I have limited knowledge of such expertise. I trust advice of consultants in your science to inform consideration of acoustical issues. Having designed projects in 46 countries I understand context is often represented incompletely in serving community needs. I will present more thorough representations of contextual forces informing my design, infusing regional voices in built work. Cultural influencers optimize design of sedate individual Korean restaurant rooms in contrast to strategies deployed in American restaurants where noise is utilized to maximize sales. I would intend to provoke this discussion. Context is generally defined as the physical setting affecting of buildings. Historically, identifiable nationalities or tribes have evolved organically over time, producing significantly unique DNA of each. These differences are most apparent in crafting buildings and conceiving art, music, and cuisine where acoustic social protocols are voiced. NATURAL FORCES affecting human comfort GEOGRAPHIC FORCES influencing integration with nature HISTORIC FORCES defining legacy of place URBAN FORCES defining constraints and opportunities PHYSICAL FORCES influencing disposition of a program on a specific site HUMAN FORCES defining community MARKET FORCES creating possibility DIGITAL FORCES redefining engagement ENGINEERING FORCES affecting psychological balance
A general overview: The appearance and evolution of spatial electroacoustic systems for ambient and other applications in the restaurant environment
Authors: Bray Wade R.
Published: November 2021

An important new factor has recently entered the restaurant acoustics environment: spatial electroacoustic systems, deployed in coordination with physical acoustic materials and procedures and architectural/interior design options. The purposes are on the one hand to eliminate noise and Lombard-speech-runaway problems while giving diners the impression of a completely natural human-driven restaurant ambience, and on the other hand to introduce additional dimensions of acoustic and visual architectural creativity while maintaining individual-table speech privacy and communication comfort. One developer has entered this field, Meyer Sound of Berkeley, California. The Constellation restaurant electroacoustic concept is discussed here in very general, orientational terms to set the stage for future detailed presentations by the practitioners. Current implementations have evolved from both the performing-arts world (Jaffe Acoustics / Jaffe Holden Acoustics ERES, Lexicon LARES and the more recent Meyer Sound Constellation performing arts electroacoustic systems) and the business world (concealed full-duplex teleconferencing systems and subtle yet effective “speech lift” and open-plan masking systems). The new restaurant systems can be used not only for controlling and optimizing ambient backgrounds, but also for differentiating the apparent acoustics of different areas and for permitting, even in a zoned manner, new opportunities in music performance.
Frequency changes in humpback whale (Megaptera novaeangliae) song units in response to small boat noise Astarte Brown Advised by Kerri D. Seger
Authors: Brown Astarte , Seger Kerri D. , Rey-Baquero Maria Paula , Huertas-Amaya L. V.
Published: November 2021

Anthropogenic noise compromises the effectiveness of communication in marine animals. This can interfere with natural auditory signal processing (for example, “masking”). Some animals have been shown to change the frequencies of their vocalizations to avoid masking. Humpback whales produce songs with low fundamental frequencies which often overlap with the low frequency content of vessel noise. In the Gulf of Tribugá, a part of the breeding grounds for humpback whale Stock G, a marine port construction project has been proposed. If constructed, underwater noise would significantly increase and potentially cause acoustic behavioral changes, negatively impacting communication efforts among the whales. This study was supported by SURIEA, and tested whether humpback whales in the Gulf of Tribugá changed the frequency content of their songs during and after boat noise as compared to before it was present. Out of 38 comparisons, song frequencies significantly changed 9 times. Additionally, out of 20 comparisons, bandwidth narrowed 11 times, broadened 9 times, shifted higher 6 times, and shifted lower 2 times. These results give greater insight into how humpback whales are able to adjust their song structure in response to small boat noise and indicate that adaptations to some anthropogenic noise sources are possible.
The social signaling behavior of humpback whales on the Hawaiian breeding grounds investigated using acoustic tags
Authors: Carvalho Jessica , Lammers Marc , Castilho Rita , Pack Adam
Published: November 2021

Humpback whales (Megaptera novaeangliae) are one of the most social of all baleen whale species. Despite extensive research into humpback whale song, gaps remain in the understanding of humpback whale communication. These gaps are particularly evident with respect to humpback whale non-song social vocalizations. This study expands upon the current understanding of non-song social call use and function by comparing call prevalence, features, and dynamics across humpback whale groups of three different compositions: dyads, escorted mother-calf pairs, and competition groups. Recordings were collected from 12 deployments of AcousondeTM acoustic and data logging tags on whales off Maui, Hawaii during the winter breeding seasons of 2019-2021. Individual social calls were selected based on visual and aural inspection of spectrograms using Raven Pro 1.6 software, with a total of 518 calls chosen throughout the 60.4 h of acoustic recordings. Of these calls, 49.2% occurred in competition groups, 33.6% in escorted mother-calf pairs, and 17.2% in dyads. Furthermore, we conducted statistical analyses to characterize and classify the social calls recorded and assess the variability of the type, quantity, and frequency of social calls used in groups of differing compositions. This study provides new insights into humpback whale vocal communication behavior in the Hawaiian Islands breeding grounds, particularly with respect to three principal social groups, whose non-song vocal communications have been understudied.
Evaluating ultrasonic vocalizations as predictors of social behavior during group interaction
Authors: Kawar Christyana , Clein Rachel S. , Warren Megan R. , Neunuebel Joshua P.
Published: November 2021

During social interaction, animals integrate sensory information—including auditory cues—to influence future behavioral decisions. For example, animals respond to distinct vocalizations with unique actions (Seyfarth et al., 1980). Mice produce ultrasonic vocalizations (USVs) associated with discrete behaviors (Sangiamo et al., 2020); however, it is unclear if USVs inform subsequent actions. To investigate the predictive power of USVs on behavior, while mice freely interacted (n = 11 groups, 2 males and 2 females per group), we continuously recorded video and audio data using a sound source localization system with an 8-channel microphone array to accurately assign vocalizations to individuals. Using machine learning-based approaches to categorize vocalizations based on acoustic properties and extract behaviors in which two mice play unique roles (actor or recipient), we found a significant interaction between particular social behaviors and preceding vocalizations. A permutation test indicated that, depending on the behavioral role of the vocalizer, specific vocalizations preceded dominant (courtship or aggressive) or submissive (avoidant) behaviors at above-chance levels. Additionally, though classifiers trained to distinguish behavioral role based on preceding vocal emission failed for some behaviors, they were successful for particular dominant behaviors. These results suggest a potentially predictive relationship between acoustic communication and subsequent behaviors.
Ketos—A deep learning package for creating acoustic detectors and classifiers
Authors: Kirsebom Oliver S. , Frazao Fabio , Padovese Bruno , Sakib Sadman , Matwin Stan
Published: November 2021

Passive acoustic monitoring is a useful technique for studying aquatic animals, but sustained observing systems require automated algorithms for detecting and classifying sounds of interest. In the last decade, deep neural networks have proven highly successful at solving a wide range of pattern recognition tasks, and recently, we have seen the first promising applications of deep neural networks to detection and classification tasks in marine bioacoustics. Deep neural networks exhibit a high degree of versatility and adaptability: the same network architecture can be trained to accomplish a multitude of tasks by feeding appropriate training data to the network without the need to modify the underlying algorithm. Thus, neural networks have the potential to transform our approach to developing acoustic detection and classification programs, enabling researchers in the field to develop or re-purpose their own programs. MERIDIAN is contributing towards this goal through the development of the open-source Python package Ketos, which provides a high-level programming interface for building training datasets and developing neural network based detectors and classifiers for analyzing underwater acoustics data. In this contribution, an overview of the software package will be given and its functionalities will be demonstrated through case studies.
An ultrasound vibro-elastography technique for assessing papilledema
Authors: Chen John J. , Zhou Boran , Kazemi Arash , Sit Arthur J. , Zhang Xiaoming
Published: November 2021

Papilledema is optic nerve swelling caused by increased intracranial hypertension, which has the potential to cause significant vision loss. Papilledema from idiopathic intracranial hypertension (IIH) is typically bilateral and symmetric, but can sometimes be asymmetric and even unilateral. The cause for this asymmetry is unknown. The purpose of this study was to develop ultrasound vibro-elastography (UVE) for assessing patients with papilledema to evaluate for biomechanical differences in these eyes. Nine patients with papilledema from IIH and 9 age-matched healthy control subjects were enrolled. A local harmonic vibration was used to generate wave propagation through the eyelid. Three excitation frequencies of 100, 150, and 200 Hz were used. A 6.4 MHz ultrasound probe was used to measure wave propagation in the eye structures. Wave speeds were measured in the posterior sclera of the maculae. The magnitudes of the wave speed of the IIH patients’ posterior sclera were significantly higher than those of healthy subjects. In patients with unilateral papilledema, the wave speed of the posterior sclera were higher in the eyes with papilledema than in the contralateral eyes without papilledema. UVE provides a noninvasive technique to measure the wave speed of posterior sclera, which is stiffer in eyes with papilledema.
Measurement of the arterial wall elasticity using the velocity of flexural waves in retinal blood vessels
Authors: Laloy-Borgna Gabrielle , Puyo Léo , Atlan Michael , Catheline Stefan
Published: November 2021

Arterial stiffness (typically a Young modulus of 100 kPa) is known to be an indicator of the cardiovascular health of a patient. It is commonly used in clinics to prevent and anticipate cardiovascular diseases. The existing methods allowing to measure the arterial wall elasticity measuring the velocity of the natural pulse wave lack of accuracy. We propose here a method consisting in using laser Doppler holography experiments to estimate the arterial wall elasticity. Laser Doppler holography experiments are performed on patients and noise correlation algorithms are used on these data to measure the wave velocity. We measured separately the wavelength and the frequency of elastic waves, allowing to calculate their velocity. Due to the temporal resolution of the raw data and to the way the data are processed, the waves we detected are not the classical axisymmetric pulse wave. The physics of guided waves indicates that both antisymmetric (called A0) and symmetric (called S0) waves can propagate in tubes, and in this case only antisymmetric flexural waves are detected. They are both sensitive to the arterial wall elasticity, and at low frequencies, flexural (or antisymmetric) waves are much slower than the axisymmetric pulse wave, about 3 mm/s, allowing to increase greatly the measurement accuracy. When knowing the diameter of the blood vessel, for the first time it is possible to retrieve the arterial wall elasticity thanks to the antisymmetric wave velocity measurement.