Using particle motion to estimate sediment properties

Gopu R Potty – gpotty@uri.edu

Department of Ocean Engineering, University of Rhode Island, Narragansett, RI, 02879, United States

James H Miller – miller@uri.edu

Popular version of 3pPA4 – Estimation of seabed properties at the New England Mud Patch using vector acoustic measurements
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Shear is one of the fundamental mechanical parameter that bridges geological, engineering, and environmental aspects of the seafloor influencing loss of acoustic energy in addition to other factors such as seafloor stability, load bearing capacity, sediment transport and deposition. Shear wave velocity is one of the parameters which characterizes shear strength of the sediments. In this study we use waves propagating along the seabed (interface waves) to estimate the shear speed of the sediments.

Interface waves:
Interface waves are waves which travel along an interface between two media. Examples include Rayleigh waves (waves which travel along land) and Scholte waves (waves along seabed). Figure 1 shows a typical scenario in which a sensor on the seabed will measure Scholte waves in addition to acoustic waves along different paths (direct, surface reflected etc.).

Diagram showing sound waves from a source reflecting off the water surface and sediment layers, detected by an OBX sensor package.Fig. 1: Schematic of a typical scenario in which a sensor on the seabed measures interface waves in addition to acoustic waves along different paths. Right panel shows the OBX sensor package.

The Scholte waves have the following characteristics:

  1. They have maximum amplitude at the water-sediment interface (seabed). The data used in this study is from a receiver deployed on the seabed.
  2. Particles in the medium traces an elliptical path in water and sediment.
  3. The magnitude of the particle motion decreases exponentially as a function of distance from the interface in both media.
  4. The ratio of the horizontal to vertical component of the particle motion is strongly correlated to the shear velocity and thickness of the sediment. In this study we have used this characteristics of the Scholte wave to estimate the shear velocity in the sediment.

We measured the particle velocities along three mutually orthogonal directions associated with Scholte waves using a senor package (Ocean Bottom Recorder or OBX, shown in the right panel of Figure 1) deployed on the seabed during an experiment in 2022 in the New England Mud patch (NEMP), 200 km south of Martha’s Vineyard in 70 m of water depth. As the name implies, NEMP has a layer of mud/clay sediments on top of sand. Many types of sources generated sound at different frequency bands in addition to sources of opportunity such as ships passing close to the experimental area. Figure 2 shows an example of the motion (velocity in mm/s) of the particle measured by the OBX during the experiment. This represents the motion of the particle for a short period of time (~ 1 seconds) in a narrow frequency band.

3D plot showing radial velocity, vertical velocity, and time with three distinct oscillating curves in orange, blue, and purple colors.Fig.2: The trace of the particle motion (hodogram) in the source-to-receiver direction (radial, shown in pink), in the vertical direction (normal to the seabed, shown in yellow). The red curve shows the path of the particle in the vertical plane containing the source and receiver.

The strong correlation of horizontal to vertical ratio (HVSR) of the particle motion to shear speed in the sediment and sediment layer thickness is demonstrated using simulated data in Figure 3. Particle motion data were simulated for a ocean environment as shown in the left panel of Figure 3. Sound speeds in the water column, sediment and basement were assumed as 1500 m/s, 1495 m/s and 1750 m/s respectively. The shear speeds in the sediment and basement were assumed as 50 m/s and 300 m/s respectively. Densities in the water column, sediment and basement were assumed as 1025 kg/m3, 1650 kg/m3 and 2000 kg/m3 respectively.

Diagram showing a water column, sediment, and basement layers with their seismic velocities and densities on the left, and an HVSR graph with a peak at 2 Hz on the right.Fig.3: Ratio of the horizontal to vertical (HVSR) particle motion amplitude as a function of frequency (right panel). Particle motion was simulated for an ocean environment as shown in the left panel.

The particle velocities of the Scholte waves for this environment were generated using a numerical model and ratio of the horizontal to vertical component of the particle motion amplitudes were calculated as a function of frequency (Figure 3; right panel). The HVSR curve shows a dominant peak at 2 Hz which correspond to the shear resonant frequency. The data measured in the NEMP experiment is used to calculate the HVSR and then identify the peak in the frequency versus HVSR curve. HVSR is then modelled for various shear speeds and layer thicknesses. The shear speed which produces the best data-model match (particularly the peak frequency) is then estimated.

Can Grass Quiet the Shore? Lab Experiments Reveal How Coastal Vegetation Muffles Sound

Christian Di Nicolantonio – dinicolantonio@cua.edu

Instagram: c.dinic
The Catholic University of America, 620 Michigan Ave., N.E., Washington, DC, 20064, United States

Diego Turo
Christopher Crognale
Ariel Wise
Teresa Ryan
Joseph Vignola
John Judge

Popular version of 5aPA6 – Modeling sound attenuation of near shore tall vegetation
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/index.php?page=IntHtml&project=ASASPRING2026&id=4065520

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Coastal marsh grass does more than just breed mosquitos, it can act as a natural sound barrier. Researchers at The Catholic University of America (CUA) have developed a laboratory method to measure and predict how fields of tall grass reduce sound levels near shorelines, with results that closely match outdoor measurements taken at Manteo, North Carolina.

Aerial view with marked GPS points connected by yellow lines showing a tracking path over water channels.Figure 1: Satellite image of the Manteo, NC field site alongside a photo of the Long Range Acoustic Device (LRAD) source and receiver setup in the marsh grass field (Receiver height highlighted in red).

Predicting how sound travels near coastlines is important for a range of applications, from understanding the acoustic environment to military and environmental monitoring. Tall grass fields that line riverbanks and coastlines absorb and scatter sound as it passes through them, but running outdoor experiments every time is not always possible, so researchers at CUA looked into alternatives.

The research team designed miniature 3D printed replicas of grass blade arrangements and tested them inside an impedance tube, a hollow cylinder used to make precise acoustic measurements. Think of it as a controlled, repeatable grass field measurement that fits on a desk.

Top and side views of green cylindrical samples with varying groove densities labeled by phi and theta angles.Figure 2: All 3D printed samples (left) and a sample mounted within the impedance tube (right)

Seven different sample configurations were tested, varying two things: the porosity of the samples, meaning how tightly packed they are, and the angle at which the blades were oriented relative to the incoming sound. One set had blades straight at 0 degrees while the other set had blades tilted at 45 degrees, mimicking the natural variation found in real grass fields. The porosity of blades ranged from 0.5 to 0.8, meaning between half and four fifths of the sample volume was open air.

Both the porosity and the angle of the blades matter. Denser blade arrangements slow sound down more and shift the frequency at which sound is most strongly absorbed. The straight 0 degree blades consistently absorbed more sound than the tilted 45 degree blades at the same porosity, because the straight blades forced the sound to travel a longer, more winding path through the sample, a property known as tortuosity.

Line graph showing alpha values versus frequency from 200 to 1600 Hz for different theta and phi angles, with red and blue curves representing theta 45° and 0° respectively.Figure 3: Absorption coefficient for all configurations, showing the shift in peak absorption with porosity and the difference between blade orientations.

By measuring how sound behaves across a range of sample thicknesses, the team estimated two key properties of each grass configuration: how fast sound travels through the medium and how quickly it loses energy, a quantity known as attenuation. These values were then extrapolated to predict how a much more open natural grass field would behave. When extended to porosities of 96% to 99%, the predicted attenuation matched the field measured value of 0.02 per meter closely.

Graph showing attenuation coefficient versus porosity for frequencies 250, 500, 750, and 1000 Hz with extrapolated curves at 0° and 45° angles.Figure 4: Extrapolated attenuation coefficients for both blade orientations, with the field measured reference value shown for comparison.

This confirms that a simple laboratory experiment on small printed samples can successfully predict the acoustic behavior of a real coastal grass field, offering a practical and repeatable tool for understanding how nature quietly does its job.

Listening to ultrasonic signals reveals the mechanical behavior of next-generation batteries

Simón Montoya-Bedoya – simonmontoyabedoya@gmail.com
Bluesky: @simontoyabe.bsky.social
Instagram: @simontoyabe
Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas, 78712-1591, United States

Prof. Michael R. Haberman (Walker Department of Mechanical Engineering, The University of Texas at Austin)

Other contributors to the research:
Donal P. Finegan (National Laboratory of the Rockies, Golden, CO, US)
Hadi Khani (Texas Materials Institute, The University of Texas at Austin)
Ofodike Ezekoye (Walker Mechanical Engineering Department, The University of Texas at Austin)

Popular version of 2aPAb4 – Non-destructive ultrasonic monitoring of next-generation lithium-ion batteries
Presented at the 189th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0040339

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Have you noticed how heavily our current society depends on batteries? Batteries are used everywhere, from powering your phone to electrifying mobility, and energy storage to mitigate the intermittent nature of renewable energy sources like wind and sun. This increased demand for lithium-ion batteries (LIBs) has led to the exploration of new technologies with improved attributes such as safer operation or improved lifetime. For example, silicon solid-state batteries (Si-SSB) are promising because silicon as an anode material offers a higher specific capacity (~3500 mAh/g) than graphite (~300 mAh/g) used in conventional LIBs. They are also potentially safer to operate due to the use of a solid electrolyte rather than the flammable liquid electrolyte used in conventional LIBs.

However, Si-SSBs come with their own challenges associated with the avoidance of a liquid electrolyte, primarily the requirement to maintain reliable interfacial contact between all the solid layers for lithium-ion movement. Si-SSBs are therefore more brittle and more prone to contact loss and fracture.

Another challenge in studying the intricate mechanical changes that arise from the electrochemical processes in the battery is that we are “blind” to them, in other words, we cannot see inside batteries while they are operating. That’s why, just as a doctor uses ultrasound to monitor a beating heart, we can use ultrasonic waves to monitor batteries without opening them, as represented by the cartoon in Fig. 1. The key to understanding what changes within the batteries is having information about how the movement of lithium ions alters its mechanical properties. When lithium ions migrate during charging and discharging, they cause swelling, internal stresses, and sometimes fracture within the battery structure. These mechanical changes can significantly affect the propagation of ultrasonic waves through the material. This is specifically true for the silicon anode, where silicon forms alloys with the lithium ions, rather than the lithium ions becoming embedded in the molecular structure as occurs in conventional batteries. These electrochemical changes lead to large volumetric and mechanical changes. Thus, SSBs are a compelling technology to explore using ultrasound using ultrasonic signals observables, such as shifts in the time of flight (TOF) of the wave through the battery, or changes in how sound is absorbed or scattered. These “acoustic fingerprints” can potentially help us gain more insights into degradation in these next-generation (“next-gen”) batteries and therefore improve the technology for more widespread use in commercial products.

Figure 1. Analogy of the usage of ultrasonic waves for battery diagnostics, similar to how a doctor would use ultrasonics to monitor heart health. [Image generated with AI using Google NanoBanana Pro]

We aim to extend the use of ultrasonic testing methods for next-gen batteries and investigate opportunities and challenges associated with evaluating this new technology. In this work, we investigated both contact-based and immersion ultrasonic testing to monitor changes in the mechanical properties of Si-SSBs under cycle-induced aging.

In general, our experiments showed an overall stiffness reduction with aging as indicated by the increase in ultrasonic wave TOF (see Fig 2a). Further, we observed an overall reduction of transmitted energy with increased cycling. These two findings may be associated with the accumulation of damage at layer interfaces associated with the creation of solid-gas interfaces and/or debonding between layers. Finally, ultrasonic imaging using immersion testing provided information regarding the distribution and evolution of damage in space as these next-gen batteries are aged (see Fig 2b).

By refining these techniques to evaluate next-gen battery technologies, we will develop more sensitive methods to determine when something is wrong before it’s too late. In a world increasingly dependent on safe and reliable energy storage, the ability to “listen” to batteries might be precisely what we need to power the clean energy revolution.

Figure 2. Evolution of cell stiffness during aging. a) Stiffness of the SSB, normalized to its initial value, plotted against discharge capacity for both charged (blue) and discharged (red) states. With representative ultrasonic images from transmitted signals at two states of the SSB: b.1) pristine before cycling, and b.2) after 40 cycles of aging. We observed a significant reduction in transmission in the middle region of the SSB. Warmer colors indicate higher transmission, and dashed outlines mark the active cell region.

Using Smartphones To Improve Disaster Search and Rescue

In disaster situations where visibility is limited, sound that can penetrate through rubble is the key to finding trapped victims quickly. #ASA_ASJ2025 #ASA189

HONOLULU, Dec. 5, 2025 — When a natural disaster strikes, time is of the essence if people are trapped under rubble. Conventional methods use radar-based detection or employ acoustics that rely on sounds made by victims.

Since most people carry their phones with them every day, Shogo Takada, a student at the University of Tokyo, is working on a way to use smartphone microphones to assist in locating disaster victims.

Takada will present his results Friday, Dec. 5, at 11:45 a.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in Honolulu, Hawaii.

A diagram showing a hypothetical search and rescue situation utilizing a smartphone microphone. Credit: Shogo Takada

A diagram showing a hypothetical search and rescue situation utilizing a smartphone microphone. Credit: Shogo Takada

“This method is effective for locating victims buried under debris or soil caused by earthquakes or landslides because sound waves can propagate through them,” said Takada. “It could also be used to locate rescuers affected by secondary disasters.”

The method combines two types of sound sources, monopole and dipole. Radiating out equally in a circle, monopole sources create sound waves around the source, whereas dipole sources radiate sound from the front and back but cancel out on the sides. Dipole sound sources are directional, which can help researchers estimate the azimuth angle of the sound source, giving them information about the source’s location.

In a disaster situation, a rescuer would emit two dipole sounds, which would be received by the microphone of a trapped victim, and then an electromagnetic wave would be sent from the victim’s phone to broadcast their location. In the presence of sound-reflecting debris, a monopole sound can also be emitted by the rescuer to help reduce the effect of the debris. All of the sound sources can be incorporated into a formula to help estimate the location of the trapped person.

Takada’s technique proved highly successful in a field test on a disaster training site. The method achieved an error of 5.04 degrees away from the hypothetical victim, when searching over an area of 10 square meters.

“One limitation is that the method assumes the victim should possess a device equipped with a microphone,” said Takada. “This is a more restrictive condition compared to traditional techniques that detect sounds or voices emitted by the victim.”

However, given the widespread use of smartphones, Takada believes that this technique is promising and plans to refine it further.

“In future work, we plan to develop a method that can estimate not only the azimuth angle but also the elevation angle of the sound source,” Takada said. “Additionally, we aim to expand the system to use two sound sources to achieve three-dimensional localization.”

Contact:
AIP Media
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——————— MORE MEETING INFORMATION ——————–

Main Meeting Website: https://acousticalsociety.org/honolulu-2025/
Technical Program: https://eppro02.ativ.me/web/planner.php?id=ASAASJ25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE ACOUSTICAL SOCIETY OF JAPAN
ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.

More Press Releases

Acoustic Suction Tweezers: A new compact acoustic gadget for small object manipulation

Shoya Yoneda – yoneda-shoya@ed.tmu.ac.jp

Department of Electrical Engineering and Computer Science
Tokyo Metropolitan University
Hino-shi, Tokyo, 191-0065
Japan

Kan Okubo – kanne@tmu.ac.jp

Popular version of 4pPA6 – Miniaturized Acoustic Suction Tweezers: Lift Control and Cap Design for Mobile Applications
Presented at the 189th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0041269

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Can you believe that ultrasound-induced forces can actually pull objects?
It may sound surprising, but this phenomenon is real. In this paper we introduce a fascinating world of sound-based manipulation.

Our research group has long been developing acoustic tweezers capable of picking up tiny objects using ultrasonic forces. (See https://youtu.be/PoZsKjst82g)

In our latest work, we take this idea a step further. By using a remarkably simple structure and cleverly harnessing the lifting force generated by sound, we have created a new acoustic gadget: the acoustic suction tweezer.

Yes —acoustic suction tweezers, sometimes called an “acoustic pipette,” pull objects toward them using sound energy, with no vacuum effect involved.

Proposal Device: Acoustic Suction Tweezer

Video 1. Introduction of the Acoustic Suction Tweezer

Sound exerts a force on objects known as the acoustic radiation force, which typically pushes objects away. However, by placing a small aperture unit in front of the transducer, we can shape a unique sound field that transforms this force into attraction and lift —almost like a miniature vacuum cleaner made of sound. To harness this effect, we developed an acoustic focusing cap through extensive trial and error, testing various designs manufactured with a 3D printer to evaluate their performance.

Figure 1. Make various Acoustic Focusing Caps

Figure 1. Make various Acoustic Focusing Caps

The figure below shows the simulated sound pressure levels. Relatively high-pressure regions are concentrated near the tip of the cap, which correlates with the generation of attractive acoustic radiation forces in this area.

Figure 3. An Example of Sound Pressure Levels Inside the Cap

Figure 2. An Example of Sound Pressure Levels Inside the Cap

How does it compare to other devices?
Our previously proposed acoustic tweezers require large transducer arrays and complex phase control (See https://www.eurekalert.org/news-releases/923462). In contrast, the acoustic suction tweezers overcome these limitations through careful design considerations. Remarkably, they lift objects even larger than the wavelength of sound, such as 15 mm polystyrene spheres.

Video 2. Lifting a 15mm sphere

Practicality
The Acoustic Suction Tweezer excels in practicality; it can be implemented quickly, at low cost, using just a 3D printer and a single ultrasonic transducer.

We confirmed that the device can handle lightweight industrial items such as coated wires and even delicate objects like feathers —materials conventional vacuum tweezers struggle to grasp.

Video 3. Lifting a coated wire

We confirmed that the device can handle lightweight industrial items such as coated wires and even delicate objects like feathers —materials conventional vacuum tweezers struggle to grasp.We expect this device to have strong potential for applications in diverse fields, including medicine, biochemistry, and engineering. We also hope that this system will inspire further innovation and the creation of many other useful acoustic-based tools.

Remotely Moving Objects Underwater Using Sound #ASA188

Remotely Moving Objects Underwater Using Sound #ASA188

Acoustic metamaterial enables pushing, rotating, and more complex movements in 3D.

Media Contact:
AIP Media
301-209-3090
media@aip.org

NEW ORLEANS, May 20, 2025 – Sound can do more than just provide a nice beat. Sound waves have been used for everything from mapping the seafloor to breaking apart kidney stones. Thanks to a unique material structure, researchers can now move and position objects underwater without ever touching them directly.

Dajun Zhang, a doctoral student at the University of Wisconsin-Madison, will present his work on developing a metamaterial for underwater acoustic manipulation Tuesday, May 20, at 3:20 p.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23.

metamaterial

The metamaterial created by Zhang is used to push and rotate an object adorned with the University of Wisconsin’s Bucky the Badger. Credit: Dajun Zhang

A metamaterial is a composite material that exhibits unique properties due to its structure. Zhang’s metamaterial features a small sawtooth pattern on its surface, which allows adjacent speakers to exert different forces on the material based on how the sound waves reflect off it. By carefully targeting the floating or submerged metamaterial with precise sound waves, Zhang can push and rotate any object attached to it exactly as much as he wants.

Manipulating objects in water without touching them could make a lot of underwater work easier. It could also be used inside the human body, which is mostly water, for applications like remote surgery or drug delivery.

“Our metamaterial offers a method to apply different acoustic radiation forces on objects in liquid media, such as underwater robots and vehicles, parts for assembly, or medical devices and drugs,” said Zhang.

However, manufacturing underwater metamaterials with the correct properties for object manipulation is difficult, especially with conventional methods.

“Current fabrication methods for underwater metamaterials do not provide the resolution or material properties required and are usually very expensive,” said Zhang. “To solve this issue, I developed a new fabrication method. This method is not only low cost and easy to implement but also achieves high fabrication resolution and large acoustic impedance contrast with water, which are keys to underwater metamaterials.”

In tests, Zhang used his metamaterial to manipulate floating objects, such as wood, wax, and plastic foam, along with objects completely submerged underwater. He attached his metamaterial to each object and used acoustic waves to push, pull, and rotate them. With submerged objects, this technique gave him the ability to manipulate them in three dimensions.

Zhang plans to continue his work, developing a metamaterial patch that is smaller and more flexible. He hopes his work will lead to new uses in medicine and underwater robotics.

“Our research opens new opportunities for both underwater acoustic metamaterials and remote manipulation,” said Zhang. “Acoustic metamaterials and metasurfaces can now be used to generate forces remotely for underwater or in-body levitation, actuation, and manipulation applications.”

——————— MORE MEETING INFORMATION ———————
Main Meeting Website: https://acousticalsociety.org/new-orleans-2025/
Technical Program: https://eppro01.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASAICA25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE INTERNATIONAL COMMISSION FOR ACOUSTICS
The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.