Articles tagged with Underwater Acoustics
Researchers found that sharks can detect low-frequency sounds from considerable distances and respond by dramatically changing direction away from the source. They detected sounds from up to 243 feet away and were more sensitive to lower frequencies.
Researchers mapped the Challenger Deep using the EM124 multibeam echosounder, finding a preferred estimate of 10,927 m, which highlights the importance of sound-speed models, vessel speed, and survey conditions. The study's dataset is publicly available, allowing for further validation and comparison with other observations.
Researchers have discovered a wave-interference effect that makes sound energy appear to outrun fundamental limits without breaking physics. This finding could improve whale tracking by pinpointing the location of whales based on the phase of their calls.
A Korean research team created an underwater acoustic lens capable of focusing sound precisely at a desired point while reducing weight by about 40% compared to conventional designs. The findings have significant implications for underwater communication, marine environmental monitoring, and acoustic energy transfer.
Researchers have developed a soft, custom-molded acoustic contact lens that actively corrects outgoing sound waves before they pass through an autonomous drone's protective shell. The lens boosts sonar signal strength by up to 10 decibels while cutting background reverberation without draining extra battery power.
Researchers developed a machine learning framework to detect and classify shell-crushing sounds, enabling the quantification of predator impacts on mollusk populations. The system uses multi-step approaches and demonstrates strong performance in controlled tank conditions and field settings.
Researchers found the Cascadia Subduction Zone to be more active than previously thought, with signs of shallow earthquakes and fluid flow detected offshore. The study suggests variable fluid pathways could alter the behavior of large earthquakes on the fault, potentially influencing the severity of future events.
Researchers analyzed over 2,000 hours of underwater recordings to detect subtle shifts in red hind spawning behavior and population dynamics. The study found a notable shift in the balance of mating calls over the 12-year period, with calls linked to competition becoming dominant.
Researchers at Griffith University developed a publicly available tool to analyze unknown sound-types in large acoustic datasets. The new protocol pinpoints river species, providing valuable insights into river ecosystems.
Researchers at UNSW Sydney discovered that leopard seal songs share structural similarities with human nursery rhymes, featuring predictable patterns and low entropy. The study found that male seals spend up to 13 hours a day singing in two-minute cycles, with each individual creating a unique sonic signature.
Researchers found that coral larvae settle near speakers in artificial reef environments, suggesting sound as an environmental cue. The study aims to develop scalable strategies using audiovisual remote sensing tools to monitor reef biodiversity.
Acoustic metamaterial enables pushing, rotating, and complex movements in 3D. Researchers can now move and position objects underwater without touching them directly, paving the way for applications like remote surgery and drug delivery.
Researchers at Purdue University have developed a metamaterial that can significantly reduce underwater noise generated by offshore wind farm installation. The technology, which uses carefully arranged plates to trap air and guide sound, achieves a 40-decibel reduction in noise levels.
Researchers use acoustics to identify corroded UXOs in shallow water, making them difficult to observe with standard sonar imaging techniques. The study helps provide better predictive tools for finding UXOs in civilian environmental demining efforts.
Baleen whale species that flee from killer whales produce calls at deep frequencies undetectable to their predators, while others sing higher-frequency songs that are easily heard. This 'flight' vs 'fight' difference influences all aspects of baleen whale behavior, from migration patterns and communication to mating and feeding habits.
A new study by Duke University finds that deep-diving whales confuse plastic debris with prey items, as its acoustic signature mimics squid. Researchers tested various types of plastic trash and found strong similarities in their acoustic signals compared to whale prey, highlighting the need for more sustainable materials.
Researchers found that commercial ship noise completely masks Cook Inlet beluga whales' most commonly used calls, compromising their critical communication. The study documents the complex vocal repertoire of the population and provides a quantified measure of masking by ship noise on their communication.
A team led by Lehigh University's Yahong Rosa Zheng is developing an Autonomous Observatory Node that can collect and transmit data from underwater sensors wirelessly, without the need for expensive subsea cables. The prototype aims to operate at depths of up to 1000 meters, enabling researchers to study extreme environments and detect...
Researchers at the University of Washington have developed an underwater 3D-positioning app for smart devices, allowing divers to accurately track each other's locations. The app uses acoustic signals and timestamps to estimate diver distances and locations, improving accuracy with more devices in the network.
Researchers recorded and identified mating and feeding sounds of 21 ocean species, including those influenced by the moon. The study's findings will contribute to the development of the Global Library of Underwater Biological Sounds (GLUBS), an open-access online platform for monitoring changes in marine environments.
Researchers at the University of Bristol collected 840 hours of underwater sound recordings from five ponds in England, revealing clear daily acoustic activity cycles. The study provides insights into the health of freshwater ecosystems and the potential for assessing species presence without disturbing the environment.
Researchers at the University of Washington developed AquaApp, a mobile app that enables underwater messaging on billions of existing smartphones and smartwatches using software. The app uses acoustic signals to transmit messages and can accommodate up to 60 unique users on its local network.
Scientists analyzed nearly two decades of underwater recordings to find that the distinctive songs of Chagos pygmy blue whales have increased in frequency over time. This suggests that stocks of the sub-species may be on the rebound after being hunted to near-extinction in the 20th century.
A team of researchers from the University of Tsukuba has developed a new approach for accurate underwater acoustic positioning in multipath environments. By using a database of signals and selectively removing reflected waves, they achieve centimeter-scale accuracy in object location, even in shallow waters.
A new tool called DeepSqueak uses deep learning to identify marine mammal calls with high accuracy, even in noisy environments. The tool was originally developed for rodent ultrasound signals but has been adapted to detect sounds at other frequencies, including humpback whales and delphinids.
A new machine learning algorithm can accurately identify fish calls from hydrophone data, enabling efficient analysis of marine environments. The method has implications for understanding changes in ocean conditions and coral reef health.
Researchers developed an attention-based deep neural network to detect multiple ship targets, exceeding conventional networks' performance. The model focused on inherent features of the two ships simultaneously, outperforming traditional approaches.
Hady Salloum and his team at Stevens Institute of Technology will commercialize an underwater security system to protect ports, ships, and supply chains from surface and underwater intruders. The system uses patented technology to detect human divers and small boats, ensuring safer travel, shipping, and logistics.
Researchers created a 3D underwater acoustic carpet cloak using transformation acoustics, hiding objects from detection instruments like sonar. The cloaked object mimicked the reflecting surface and was undetectable in every direction.
A new underwater acoustic localization system has been developed to estimate the trajectory of sound sources in the ocean without multiple receivers or anchor nodes. The system uses bathymetry information to discriminate the location of the source of the signal.
Researchers at Chinese Academy of Sciences create first underwater acoustic carpet cloak using transformation acoustics, controlling sound wave propagation. The carpet cloak, composed of layered brass plates, successfully mimics a reflecting plane and makes the cloaked object imperceptible to sound detection.
The University of New Hampshire will study ocean ecosystems using underwater acoustic technology in the mid- and south Atlantic Ocean. The research aims to understand patterns and trends in regional ocean soundscapes and processes, including climate change.
Megan S. Ballard receives the R. Bruce Lindsay Award from the Acoustical Society of America for her contributions to underwater acoustic propagation modeling and inversion techniques in acoustical oceanography. The award recognizes her research on sound field calculation in complex underwater environments.
Most aquatic species sense sound via particle motion, yet few studies have included measurements. Researchers from the University of Exeter and others have developed user-friendly tools to maximize its uptake and understand the impact of man-made noise on aquatic life.
Henry Cox, Senior Fellow at Lockheed Martin, has made fundamental and practical contributions to array signal processing, underwater acoustics, and sonar systems engineering. The Helmholtz-Rayleigh Silver Medal is awarded for interdisciplinary contributions named after two great pioneers of acoustics.
A new coupled normal mode method is presented to solve range-dependent propagation problems in underwater acoustics. The proposed method is accurately validated through comparison with analytical solutions and demonstrates high computational efficiency.