Acoustic contrast factor

Acoustic contrast factor

The acoustic contrast factor is a number used to describe the relationship between the densities and the sound velocities (or, equivalently because of the form of the expression, the densities and compressibilities) of two media. It is most often used in the context of biomedical ultrasonic imaging techniques using acoustic contrast agents and in the field of ultrasonic manipulation of particles much smaller than the wavelength using ultrasonic standing waves. In the latter context, the acoustic contrast factor is the number which, depending on its sign, tells whether a given type of particle in a given medium will be attracted to the pressure nodes or anti-nodes.

Example - particle in a medium

Given the compressibilities eta and etap and densities ho and hop of the medium and particle, respectively, the acoustic contrast factor phi can be expressed as

:phi = {frac{5 ho_p-2 ho}{2 ho_p+ ho-{frac{eta_p}{eta

For a positive value of phi , the particles will be attracted to the pressure nodes, and vice versa.

ee also

References

External links


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Ultrasound — Not to be confused with Supersonic .Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Although this limit varies from person to person, it is approximately 20 kilohertz (20,000 hertz) in healthy,… …   Wikipedia

  • Life Sciences — ▪ 2009 Introduction Zoology       In 2008 several zoological studies provided new insights into how species life history traits (such as the timing of reproduction or the length of life of adult individuals) are derived in part as responses to… …   Universalium

  • Diffraction topography — (short: topography ) is an X ray imaging technique based on Bragg diffraction. Diffraction topographic images ( topographs ) record the intensity profile of a beam of X rays (or, sometimes, neutrons) diffracted by a crystal. A topograph thus… …   Wikipedia

  • Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry       The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …   Universalium

  • performing arts — arts or skills that require public performance, as acting, singing, or dancing. [1945 50] * * * ▪ 2009 Introduction Music Classical.       The last vestiges of the Cold War seemed to thaw for a moment on Feb. 26, 2008, when the unfamiliar strains …   Universalium

  • phonetics — /feuh net iks, foh /, n. (used with a sing. v.) 1. the science or study of speech sounds and their production, transmission, and reception, and their analysis, classification, and transcription. Cf. acoustic phonetics, articulatory phonetics,… …   Universalium

  • radiation — radiational, adj. /ray dee ay sheuhn/, n. 1. Physics. a. the process in which energy is emitted as particles or waves. b. the complete process in which energy is emitted by one body, transmitted through an intervening medium or space, and… …   Universalium

  • Phonological change — Sound change and alternation Metathesis Quantitative metathesis …   Wikipedia

  • Holy Wood (In the Shadow of the Valley of Death) — Holy Wood (In the Shadow of the Valley of Death) …   Wikipedia

  • linguistics — /ling gwis tiks/, n. (used with a sing. v.) the science of language, including phonetics, phonology, morphology, syntax, semantics, pragmatics, and historical linguistics. [1850 55; see LINGUISTIC, ICS] * * * Study of the nature and structure of… …   Universalium

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”