This paper presents simplified hydrodynamics model for a biomimetic robot fish based on quantitative morphological and kinematic parameters of crangiform fish. The motion of four Pangasius sanitwongsei with different length and swimming speed were recorded by the digital particle image velocimetry (DPIV) and image processing methods and optimal coefficients of the motion equations and appropria...

Using Doppler velocity data from the SOI/MDI instrument onboard the SoHO spacecraft, we do time-distance helioseismic inversions for sound-speed perturbations beneath 16 sunspots observed in high-resolution mode. We clearly detect ring-like regions of enhanced sound speed beneath most sunspot penumbrae, extending from near the surface to depths of about 3.5 Mm. Due to their location and depende...

For non-radial solar p modes we calculate corrections to the eigenfrequencies arising from the sound speed and velocity inhomogeneity of the convection zone. We use a simple periodic model, and obtain the frequency corrections by solving a Hill determinant. The frequency shifts are significant, and in most cases negative; they increase in magnitude with increasing frequency and harmonic degree ...

To investigate further the origin of the second heart sound we studied human subjects, dogs, and a model in vitro of the cardiovascular system. Intra-arterial sound, pressure, and, where possible, flow and high speed cine (2,000 frames/sec) were utilized. The closure sound of the semilunar valves was of higher amplitude in be ventricles than in their respective arterial cavities. The direction ...

In this paper we demonstrate the applicability of a high speed pneumatic servovalve for active noise control (ANC). Pressurized air is fluctuated using the servovalve to produce sound at commandable amplitude and frequency. The paper presents results of a noise cancellation experiment with an acoustic duct structure where disturbance produced by a speaker is overwhelmed by the high speed pneuma...

BACKGROUND Male parasitic wasps attract females with a courtship song produced by rapid wing fanning. Songs have been described for several parasitic wasp species; however, beyond association with wing fanning, the mechanism of sound generation has not been examined. We characterized the male courtship song of Cotesia congregata (Hymenoptera: Braconidae) and investigated the biomechanics of sou...

A critical knowledge gap in our understanding of the interaction of sound with the ocean bottom is the frequency dependence of sound speed and attenuation in marine sediments. The long term goals of this research project are related to the investigation of dispersion of sound speed and attenuation at low frequencies (< 2 kHz) in different types of marine sediments. The research involves develop...

A critical knowledge gap in our understanding of the interaction of sound with the ocean bottom is the frequency dependence of sound speed and attenuation in marine sediments. The long term goals of this research project are related to the investigation of dispersion of sound speed and attenuation at low frequencies (< 2 kHz) in different types of marine sediments. The research involves develop...

A critical knowledge gap in our understanding of the interaction of sound with the ocean bottom is the frequency dependence of sound speed and attenuation in marine sediments. The long term goals of this research project are related to the investigation of dispersion of sound speed and attenuation at low frequencies (< 2 kHz) in different types of marine sediments. The research involves develop...