Large surface wave breaking events in deep water are acoustically detectable by beamforming at 5-6 kHz with a mid-frequency planar array located 130 m below the surface. Due to the array's depth and modest 1 m horizontal aperture, wave breaking events cannot be tracked accurately by beamforming alone. Their trajectories are estimated instead by splitting the array into sub-arrays, beamforming each sub-array toward the source, and computing the temporal cross-correlation of the sub-array beams. Source tracks estimated from sub-array cross-correlations match the trajectories of breaking waves that are visible in aerial images of the ocean surface above the array.
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http://dx.doi.org/10.1121/10.0026149 | 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.
View Article and Find Full Text PDFACS Omega
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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