Sound pressure | EPFL Graph Search

Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa). A sound wave in a transmission medium causes a deviation (sound pressure, a dynamic pressure) in the local ambient pressure, a static pressure. Sound pressure, denoted p, is defined by where ptotal is the total pressure, pstat is the static pressure. Sound intensity In a sound wave, the complementary variable to sound pressure is the particle velocity. Together, they determine the sound intensity of the wave. Sound intensity, denoted I and measured in W·m−2 in SI units, is defined by where p is the sound pressure, v is the particle velocity. Acoustic impedance Acoustic impedance, denoted Z and measured in Pa·m−3·s in SI units, is defined by where is the Laplace transform of sound pressure, is the Laplace transform of sound volume flow rate. Specific acoustic impedance, denoted z and measured in Pa·m−1·s in SI units, is defined by where is the Laplace transform of sound pressure, is the Laplace transform of particle velocity. Particle displacement The particle displacement of a progressive sine wave is given by where is the amplitude of the particle displacement, is the phase shift of the particle displacement, k is the angular wavevector, ω is the angular frequency. It follows that the particle velocity and the sound pressure along the direction of propagation of the sound wave x are given by where vm is the amplitude of the particle velocity, is the phase shift of the particle velocity, pm is the amplitude of the acoustic pressure, is the phase shift of the acoustic pressure.

A Tunable Self-Offloading Module for Plantar Pressure Regulation in Diabetic Patients

Yves Perriard, Yoan René Cyrille Civet, Paolo Germano, Christian Köchli, Sofia Lydia Ntella, Kenny Jeanmonod, Bhawnath Tiwari

Plantar pressure plays a crucial role in the pathogenesis of foot ulcers among patients with diabetes and peripheral polyneuropathy. Pressure relief is a key requirement for both the prevention and treatment of plantar ulcers. Conventional medical practice ...

2024

SVGC-AVA: 360-Degree Video Saliency Prediction With Spherical Vector-Based Graph Convolution and Audio-Visual Attention

Pascal Frossard, Chenglin Li, Li Wei, Qin Yang, Yuelei Li, Hao Wang

Viewers of 360-degree videos are provided with both visual modality to characterize their surrounding views and audio modality to indicate the sound direction. Though both modalities are important for saliency prediction, little work has been done by joint ...

Ieee-Inst Electrical Electronics Engineers Inc2024

Laser Doppler Vibrometer measurements of the 3D pressure field for the estimation of the radiation force produced by an acoustic standing-wave levitator

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Acoustic levitation devices use powerful ultrasonic standing waves to levitate objects in mid-air. We have created a system and method to measure the full harmonic content of the acoustic field accurately. Our study revealed that levitated particles alter ...

Elsevier Science Sa2024