The dynamic interplay between static and sliding friction is fundamental to many animal movements. One interesting example of stick-slip friction is found in the sound-producing apparatus of many spiny lobster species (Palinuridae). The acoustic movements of the spiny lobster's plectrum over the file are generated by stick-slip friction between the two surfaces. We examined the microscopic anat...

The paper deals with the distributed acoustic localization of teams of autonomous underwater vehicles (AUVs) and proposes a novel algorithm, real-time raytracing (RT2), for evaluating the distance between any pair of AUVs in the team. The technique, based on a modified formulation of the non-linear sound-ray propagation laws, allows efficient handling of the distorted and reflected acoustic ray...

In consideration of physical and chemical properties of pure substances, speed of sound is one of important quantity which can used to calculate many of other thermo-physical properties such as isothermal compressibility, Joule-Thomson coefficient, isobaric heat capacity and etc. These thermo-physical properties are the main parameters in industrial and chemical processes. Development of accura...

Condensation of atoms from the vapor into a third sound resonance is expected to be capable of acoustic amplification. This results from normal to superfluid conversion that coherently accommodates atoms into the third sound velocity field. Consideration of third sound in light of the equilibrium detailed balance between vapor particles and the superfluid film provides further evidence that aco...

Brillouin scattering in optical fibres is a fundamental interaction between light and sound with important implications ranging from optical sensors to slow and fast light. In usual optical fibres, light both excites and feels shear and longitudinal bulk elastic waves, giving rise to forward-guided acoustic wave Brillouin scattering and backward-stimulated Brillouin scattering. In a subwaveleng...

Recent improvements in fiber properties combined with their broadband acoustic dissipation characteristics make such materials potentially desirable for implementation in silencers. The acoustic modelling of simple silencer geometries, such as circular or rectangular cross-sections, has been established and classified depending on the assumption of locallyor bulk-reacting lining. Morse [1] used...

1- introduction this research attempts to investigate the effects of forensically-relevant facial concealment on voiceless fricatives /f, s, ʃ/ in farsi. there are various types of face-concealing garments that are commonly worn by people for the occupational, recreational, religious, and cultural purposes .these coverings may be typically used as disguises during the commission of crime by del...

The acoustic design of auditoria involves the specification of the room geometry and boundary properties, and any additional acoustic elements such as reflectors or diffusers, to usefully direct sound to produce a desired subjective experience, quantified by measurable acoustic parameters. This design must take into account the reflection of sound within the stage area, the early reflections fr...

This paper experimentally investigates the acoustic properties of an orifice with bias flow under medium and high sound level excitation. The test included no bias flow and two bias speeds for three different frequencies. Experimental results are compared and discussed with theory. It is shown that bias flow makes the acoustic properties much more complex compared theory and with the no bias fl...

The combination of semiconductor quantum well structures and strongly piezoelectric crystals leads to a system in which surface acoustic waves with very large amplitudes can interact with charge carriers in the well. The surface acoustic wave induces a dynamic lateral superlattice potential in the plane of the quantum well which is strong enough to spatially break up a two-dimensional electron ...