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Output of a computer model of underwater acoustic propagation in a simplified ocean environment. A seafloor map produced by multibeam sonar. Underwater acoustics (also known as hydroacoustics) is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries.
Biomass estimation is a method of detecting and quantifying fish and other marine organisms using sonar technology. [1] An acoustic transducer emits a brief, focused pulse of sound into the water. If the sound encounters objects that are of different density than the surrounding medium, such as fish, they reflect some sound back toward the source.
Sonar (sound navigation and ranging or sonic navigation and ranging) [2] is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances , communicate with or detect objects on or under the surface of the water, such as other vessels.
Aquatic animals can produce both water-soluble and water-insoluble pheromones, though they mostly produce soluble signals for ease of dispersion in the water environment. [22] Water-soluble chemicals are often dispersed into the surrounding fluid, while water-insoluble chemicals are expressed at the body surface of the animal.
The oceans are fairly transparent to low-frequency acoustics, however. The oceans conduct sound very efficiently, particularly sound at low frequencies, i.e., less than a few hundred hertz. [3] These properties motivated Walter Munk and Carl Wunsch [4] [5] to suggest "acoustic tomography" for ocean measurement in the late 1970s. The advantages ...
These will absorb a part of the vibrations (and the noise) produced by the machines. To control the electromagnetic vibrations at the origin, skewing the electric motor or choosing a better slot/pole combination [3] will reduce electromagnetic force harmonics or avoid resonances between magnetic forces and structural modes of the electric motor.
WASHINGTON (Reuters) -President-elect Donald Trump said on Saturday the U.S. should not be involved in the conflict in Syria, where rebel forces are threatening the government of President Bashar ...
The lateral line in fish and aquatic forms of amphibians is a detection system of water currents, consisting mostly of vortices. The lateral line is also sensitive to low-frequency vibrations. It is used primarily for navigation, hunting, and schooling. The mechanoreceptors are hair cells, the same mechanoreceptors for vestibular sense and hearing.