During an experiment in deep water off the coast of Southern California, wind speeds ranged from 10 to 15 m/s and wind forcing produced large breaking waves. A mid-frequency vertical planar hydrophone array recorded underwater ambient noise while an airplane equipped with a high-resolution video camera captured images of the sea surface above the array. Beams of ambient noise between 5 and 6 kHz were projected onto the sea surface and synchronized in space and time with the aerial images. Despite the array's limited azimuthal resolution of the surface, due to its modest 1 m horizontal aperture and relatively deep 130 m deployment depth, concentrated areas of high intensity in the acoustic surface projection were observed to match visible breaking events in the aerial images.
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http://dx.doi.org/10.1121/10.0021969 | DOI Listing |
Chaos
January 2025
School of Mathematics and Statistics, Jiangsu Normal University, Xuzhou 221116, China.
We demonstrate that fundamental nonlinear localized modes can exist in the Chen-Lee-Liu equation modified by several parity-time (PT) symmetric complex potentials. The explicit formula of analytical solitons is derived from the physically interesting Scarf-II potential, and families of spatial solitons in internal modes are numerically captured under the optical lattice potential. By the spectral analysis of linear stability, we observe that these bright solitons can remain stable across a broad scope of potential parameters, despite the breaking of the corresponding linear PT-symmetric phases.
View Article and Find Full Text PDFBMC Public Health
January 2025
Department of Work,Organisation and Society, Ghent University, Henri Dunantlaan 2, Ghent, Belgium.
Background: Compressed schedules, where workers perform longer daily hours to enjoy additional days off, are increasingly promoted as a workplace well-being intervention. Nevertheless, their implications for work-related well-being outcomes, such as recovery from work and burnout risk, are understudied. This gap leaves employers with little evidence on whether and how the arrangement contributes to workplace well-being.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Mechanical Engineering, North Carolina A & T State University,1601 E. Market Street, Greensboro, NC 27411, USA.
Damage in composite laminates evolves through complex interactions of different failure modes, influenced by load type, environment, and initial damage, such as from transverse impact. This paper investigates damage growth in cross-ply polymeric matrix laminates under tensile load, focusing on three primary failure modes: transverse matrix cracks, delaminations, and fiber breaks in the primary loadbearing 0-degree laminae. Acoustic emission (AE) techniques can monitor and quantify damage in real time, provided the signals from these failure modes can be distinguished.
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December 2024
Shenmu Ningtiaota Mining Company, Shaanxi Coal and Chemical Industry Group, Shenmu, Shaanxi 719300, China.
Given that conducting controllable shock wave tests in actual rock formations underground in coal mines affects coal mine production with the parameters required for equipment design and incurs significant costs, a series of ground tests were conducted separately. First, the impact of energy storage on rock breaking efficiency was analyzed. Then, physical simulation experiments were conducted on the differential efficiency of controllable shock waves on high-strength cement, sandstone, granite, solid granite, and limestone.
View Article and Find Full Text PDFThe increasing demand for controlling electromagnetic waves has led to the construction of a variety of metasurface absorbers with different functionalities. In this Letter, we designed a kind of single-layer metasurfaces with delicately designed hybrid magnetic meta-atoms (HMMAs), which can be operated as perfect absorbers (PAs) for the electromagnetic wave incident at a specified direction, but at the mirror symmetric direction, the nearly total reflection is achieved. This remarkable nonreciprocal phenomenon arises from the time-reversal symmetry (TRS) breaking nature of magnetic surface plasmon as well as the lattice Kerker effect due to the interaction of HMMAs in the single-layer metasurfaces.
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