University of Washington 1013 NE 40th St. Seattle WA 98105
Popular version of 2aPAb – Designing an array for acoustic manipulation of kidney stones Presented Tuesday morning, May 24, 2022 182nd ASA Meeting Click here to read the abstract
Ultrasound technology is becoming an important treatment tool. For instance, sound waves can apply a radiation pressure that can displace an object. Multi-element arrays are complex ultrasound sources that consist of several small transducers that can be driven in sync or a specific order to output pressure waves with different shapes. Pressure wave shapes that have a doughnut shape or a long tube are useful as they can trap an object in the center and as we control the location of the doughnut the object follows. This technology can be used to trap small kidney stones or stone fragments and move them from the kidney collection areas toward the kidney exit without surgery. We have demonstrated the ability to move kidney stone models in the bladders transcutaneously in live pigs under anesthesia. We are currently designing a new multi-element array that will enable us to adapt this technology to move stones in the complex structure of the kidney over larger distances. This technology will reduce the surgery associated with kidney stone treatments by removing small stones or fragments before they become larger, which will lead to surgery, and eliminating emergency room visits by relieving blockages from these stones or fragments.
Controlled steering of kidney stones toward the kidney exit with an ultrasound array.
It’s an understatement to say that rockets are loud. The high-speed exhaust rushing out of the nozzles mixes with the surrounding air, creating sound waves that can be heard over great distances. Even several miles away the sound waves can vibrate your whole body as the rocket lifts off and rides its pillar of fire into the cosmos.
If you watch a SpaceX Falcon 9 launch, you may be treated to another impressive experience: watching the rocket’s first-stage booster return to Earth in a “flyback” maneuver and land (see Figure 1). During flyback, the booster falls through the atmosphere at supersonic speeds, with increasing drag from an ever-thickening atmosphere gradually slowing its descent. Seconds before a would-be impact, a single rocket engine fires up again, landing legs deploy, and the rocket lands safely. Depending on your location, not only will you hear the engine firing during the landing, but it may also be preceded by a startling, rapid sequence of loud bangs. No, the rocket hasn’t exploded; this is the Falcon 9’s unique “triple sonic boom” caused by its unique geometry and flight profile while it was still high above you and falling at supersonic speeds.
“Figure 1. Left: Photo of a Falcon 9 launch. Photo from NASA/Joel Kowsky, public domain. Right: Photo of a Falcon 9 booster landing. Photo from SpaceX Photos, public domain.”
Considering how loud this “triple boom” is, let’s take a look at its pressure waveform in relation to the other launch and landing noise. Figure 2 shows a microphone recording of an entire Falcon 9 launch and landing at Vandenberg Space Force Base over a period of 10 minutes at a distance of 5 miles from the launch and landing pads. Also shown are half-second snippets of the waveform during each of three main phases. The launch noise, indicated in red, is littered with shocks (nearly instantaneous changes in pressure) while the landing noise, indicated in green, contains many shocks of smaller amplitude and lesser steepness. All three phases of noise contain shock-like content, but the sonic boom, indicated in blue, is much larger in amplitude.
“Figure 2. A Falcon 9 launch recording, around 5 miles away from the launch and landing sites.”
In order to determine the “sound exposure” of ground observers, we can use the Sound Exposure Level (SEL) metric over each section of the recording, as it accounts for both the amplitude and duration of the recording. The launch phase, calculated over 150 seconds, has an SEL of 127 dB (re 400 pPa2 s). However, the sonic boom – less than 1 second long – has an SEL of 124 dB. Although the boom’s duration is shorter than the launch, the amplitude is much greater, resulting in a total SEL similar to that of the entire launch noise. Lastly, the landing noise after the sonic boom (19 seconds) has an SEL of 112 dB.
This brief analysis shows that the landing noise (including the sonic boom) contributes a large amount of noise, similar to that of the launch phase, and needs to be considered when studying the effects of rocket launches on communities and environments.
Dr. Prince Nana AMANIAMPONG, prince.nana.amaniampong@univ-poitiers.fr CNRS Chargé de Recherche (CRCN) Bâtiment B1, Rue Marcel Doré, TSA41105 86073 – Poitiers Cedex 9 (France)
Popular version of 1pPA1 – Ammonia chemistry: Sounds better with ultrasound Presented Monday morning, May 23, 2022 182nd ASA Meeting Click here to read the abstract
Hydrazine (N2H4) is a chemical of outmost importance in the chemical industry. The global hydrazine market was valued at 510.95 million USD in 2020, and is projected to reach 806.09 million by 2030, mostly boosted by the growing need of our society for the manufacture of polymer foams and agrochemicals. Moreover, hydrazine is used in space vehicles in the form of propellant to reduce the overall concentration of dissolved oxygen. The direct production of hydrazine from ammonia (NH3) is economically and environmentally highly attractive, but it remains a very difficult task. One of the reason stems from the high bond dissociation energy of N-H bond in NH3 (435 kJ/mol), requiring harsh conditions of temperature and pressure, which are not compatible with the stability of hydrazine. Indeed the composition of hydrazine is thermodynamically more favorable than the conversion of ammonia to hydrazine, making the accumulation of hydrazine scientifically challenging.
In this work, we show that cavitation bubbles created by ultrasonic irradiation of aqueous NH3 at a high frequency, act as micro-reactors to activate and convert NH3 to amino species, without assistance of any catalyst, yielding hydrazine at the bubble-liquid interface (Figure 1). The compartmentation of the in-situ produced hydrazine in the bulk solution, which is maintained close to 30 °C, advantageously prevents its thermal degradation, a recurrent problem faced by previous technologies.
Figure 1. Cavitation bubbles act as micro-reactors to activate ammonia towards hydrazine formation.
With this technology, a maximum hydrazine production rate of 0.17 mmol.L-1.h-2 in 7 wt. % ammonia solution was achieved (Figure 2). This work opens up new avenues toward the production of hydrazine for industrial and commercial applications using high frequency ultrasound activation technologies.
Figure 2. Effect of NH3 concentration on the formation of hydrazine (525 kHz, 0.17 W/mL, 30 °C)
This is has been recently published in Angewandte Chemie International Edition, Anaelle Humblot et al., 60, 48, 25230-25234 (doi.org/10.1002/anie.202109516) and was also highlighted as the front cover image of the issue.
Filtering Microplastics Trash from Water with Acoustic Waves
Prototype speaker system efficiently separates out microplastics from polluted water
Media Contact: Larry Frum AIP Media 301-209-3090 media@aip.org
SEATTLE, November 29, 2021 — Microplastics are released into the environment by cosmetics, clothing, and industrial processes or from larger plastic products as they break down naturally.
The pollutants eventually find their way into rivers and oceans, posing problems for marine life. Filtering and removing the small particles from water is a difficult task, but acoustic waves may provide a solution.
Dhany Arifianto, of the Institut Teknologi Sepuluh Nopember in Surabaya, Indonesia, will discuss a filtration prototype in his presentation, “Using bulk acoustic waves for filtering microplastic on polluted water,” on Monday, Nov. 29 at 6:10 p.m. Eastern U.S. at the Hyatt Regency Seattle. The presentation is part of the 181st Meeting of the Acoustical Society of America, taking place Nov. 29 to Dec. 3.
Arifianto and his team used two speakers to create acoustic waves. The force produced by the waves separates the microplastics from the water by creating pressure on a tube of inflowing water. As the tube splits into three channels, the microplastic particles are pressed toward the center as the clean water flows toward the two outer channels.
The prototype device cleaned 150 liters per hour of polluted water and was tested with three different microplastics. Each plastic was filtered with a different efficiency, but all were above 56% efficient in pure water and 58% efficient in seawater. Acoustic frequency, speaker-to-pipe distance, and density of the water all affected the amount of force generated and therefore the efficiency.
The acoustic waves may impact marine life if the wave frequency is in the audible range. The group is currently studying this potential issue.
“We believe further development is necessary to improve the cleaning rate, the efficiency, and particularly the safety of marine life,” said Arifianto.
WORLDWIDE PRESS ROOM In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 word summaries of presentations written by scientists for a general audience and accompanied by photos, audio and video. You can visit the site during the meeting at https://acoustics.org/world-wide-press-room/.
PRESS REGISTRATION We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org 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 (ASA) 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/.
Alessio Medda, PhD – Alessio.Medda@gtri.gatech.edu Robert Funk, PhD – Rob.Funk@gtri.gatech.edu Krish Ahuja, PhD – Krish.Ahuja@gtri.gatech.edu Aerospace, Transportation & Advanced Systems Laboratory Georgia Tech Research Institute Georgia Institute of Technology 260 14th Street NW Atlanta, GA 30332
Walter Carr, PhD – walter.s.carr.civ@mail.mil Bradley Garfield – bradley.a.garfield.ctr@mail.mil Walter Reed Army Institute of Research (WRAIR) 503 Robert Grant Avenue Silver Springs MD 20910
Popular version of 3pPA4 – Infrasound Signature Measurements for U.S. Army Infantry Weapons During Training Presented Wednesday morning, December 1, 2021 181st ASA Meeting, Seattle, WA Click here to read the abstract
Infrasound is defined as an acoustic oscillation with frequencies below the typical lower threshold of human hearing, typically 20 Hz. Although infrasound is considered too low in frequency for humans to hear, it was shown that infrasound could be heard down to about 1 Hz. In this low-frequency range, single frequencies are not perceived as pure tones but are experienced as shocks or pressure waves, through the harmonics generated by the distortion from the middle and inner ear. Moreover, it has been shown that infrasound exposure also can have an effect on the human body, when sound of sufficient intensity is absorbed and stimulates biological tissue to produce effects similar to whole-body vibrations.
United States military personnel are exposed to blast overpressure from a variety of sources during training and military operations. While it is known that repeated exposure to high-level blast overpressure may result in concussion like symptoms, the effect of repeated exposure to low-level blast overpressure is not well understood yet. Exposure to low-level blast rarely produces a concussion, but anecdotal evidence from soldiers indicates that it can still produce transient neurological effects. During interviews, military personnel described the effect of firing portable antitank weapons like “getting punched in your whole body.” In addition, military personnel involved with breaching operations often use the term “breacher’s brain” to identify symptoms that include headache, fatigue, dizziness, and memory issues. Impulsive acoustic sources such as pressure waves generated by explosions, artillery launches, and rocket launches are typically characterized by a broadband acoustic energy with frequency components well into the infrasound range. In this study, we explore how routine infantry training can result in high level repeated infrasound exposures by analyzing acoustic recordings and highlighting the presence of infrasound.
We present results in the form of time-frequency plots, which have been generated using a technique based on wavelets, a mathematical approach that represents a signal at different scales and uses unique features at each scale. This technique is called Synchrosqueezed Wavelet Transform and it was proposed by Daubechies et al. in 2011. In Figure 1 we show examples of high energy infrasound for three weapons commonly used during infantry training in the US military. Figure 1(A) shows the time-frequency plot of a grenade explosion, Figure 1(B) shows the time-frequency plot obtained from recordings of machine gun fire, and Figure 1(C) shows the time-frequency plot obtained from a recording of a rocket launched from a shoulder-held weapon.
Results indicate that high infrasound levels are present during military training events where impulsive noise is present. Also, service members that are routinely part of these training exercises have reported concussion-like symptoms associated with training exposures.
Through this research, we have an opportunity to establish the nature of the potential threat from infrasound in training environments as a preparation for future studies aimed at developing dose-response relationships between neurophysiological outcomes and environmental measurements.
Time-frequency spectrum for recordings of (A) Grenade Blast, (B) Machine Gun fire, and (C) Rocket Launcher from shoulder weapon. Regions characterized by high energy appear hotter (red) while normal conditions are cooler (blue).
A Midsummer Flights Dream: Detecting Earthquakes from Solar Balloons
Leo Martire (NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA) – leo.martire@jpl.nasa.gov Siddharth Krishnamoorthy (NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA) Attila Komjathy (NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA) Daniel Bowman (Sandia National Laboratories, Albuquerque, NM) Michael T. Pauken (NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA) Jamey Jacob (Oklahoma State University, Stillwater, OK) Brian Elbing (Oklahoma State University, Stillwater, OK) Emalee Hough (Oklahoma State University, Stillwater, OK) Zach Yap (Oklahoma State University, Stillwater, OK) Molly Lammes (Oklahoma State University, Stillwater, OK) Hannah Linzy (Oklahoma State University, Stillwater, OK) Zachary Morrison (Oklahoma State University, Stillwater, OK) Taylor Swaim (Oklahoma State University, Stillwater, OK) Alexis Vance (Oklahoma State University, Stillwater, OK) Payton Miles Simmons (Oklahoma State University, Stillwater, OK) James A. Cutts (NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA)
NASA Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, CA 91109
Earthquakes cause the Earth’s surface to act as a giant speaker producing extremely low frequency sound in the atmosphere, called infrasound, similar to how striking a drum produces audible sound. Because sound attenuation is weak at these low frequencies, infrasound propagates very efficiently in the Earth’s atmosphere, and can be recorded at distances up to hundreds of kilometers.
As a result, pressure sensors carried by high-altitude balloons can record the direct infrasound induced by earthquakes. Our balloons carry two pressure sensors to help detect and characterize the so-called seismic infrasound. The study of infrasound is a viable proxy for measuring the motion of the ground: indeed, computer simulations and previous balloon experiments have shown that the infrasound signal retains information about the earthquake that generated it.
Drone footage of a solar-heated balloon carrying two infrasound sensors over Oklahoma, just after take-off. Notice how the lower instrument is being reeled down to increase sensor separation.
The interior of Venus, Earth’s sister planet, remains a mystery as of today. Unlike Mars, the surface of which has been explored by numerous landers and rovers, the surface of Venus is particularly inhospitable: atmospheric pressure is 92 times that on Earth, and the temperature can exceed 475 degrees Celsius. This makes direct ground motion measurements particularly challenging. However, balloons flying in the Venusian cloud layer would encounter much more temperate conditions (~0 degree Celsius and Earth’s sea level atmospheric pressure), and could therefore survive long enough to make significant records of venusquake-induced infrasound.
On July 22, 2019, Brissaud et al. conducted the first ever experiment to detect the infrasonic signature of a magnitude 4.2 earthquake in California from a high-altitude balloon. During the summer of 2021, NASA’s Jet Propulsion Laboratory (JPL), Oklahoma State University (OSU), and Sandia National Laboratories (SNL) collaborated to increase the number of detections by launching infrasound sensors over the seismically-active plains of Oklahoma. The team used an innovative solar hot air balloon design to reduce the cost and complexity that comes with traditional helium balloons.
Launching an infrasound solar-heated balloon from Oklahoma State University’s Unmanned Aircraft Flight Station (Glencoe, OK)
Over the course of 68 days, 39 balloons were launched in hope of capturing the seismo-acoustic signal of some of the 743 Oklahoma earthquakes. Covering an average distance of 325 km per day and floating at an average altitude of 20 km above sea level, the balloons passed close to 126 weak earthquakes, with a maximum magnitude of 2.8. We are now analyzing this large dataset, which is potentially filled with infrasound signatures of earthquakes, thunderstorms, and several human-caused signals such as chemical explosions and wind farms.
This flight campaign allowed the team to optimize the design of balloon instrumentation for the detection of geophysical events on Earth, and hopefully on Venus in the future.
