کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1759759 1019295 2010 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Microfoam formation in a capillary
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم آکوستیک و فرا صوت
پیش نمایش صفحه اول مقاله
Microfoam formation in a capillary
چکیده انگلیسی

The ultrasound-induced formation of bubble clusters may be of interest as a therapeutic means. If the clusters behave as one entity, i.e., one mega-bubble, its ultrasonic manipulation towards a boundary is straightforward and quick. If the clusters can be forced to accumulate to a microfoam, entire vessels might be blocked on purpose using an ultrasound contrast agent and a sound source.In this paper, we analyse how ultrasound contrast agent clusters are formed in a capillary and what happens to the clusters if sonication is continued, using continuous driving frequencies in the range 1–10 MHz. Furthermore, we show high-speed camera footage of microbubble clustering phenomena.We observed the following stages of microfoam formation within a dense population of microbubbles before ultrasound arrival. After the sonication started, contrast microbubbles collided, forming small clusters, owing to secondary radiation forces. These clusters coalesced within the space of a quarter of the ultrasonic wavelength, owing to primary radiation forces. The resulting microfoams translated in the direction of the ultrasound field, hitting the capillary wall, also owing to primary radiation forces.We have demonstrated that as soon as the bubble clusters are formed and as long as they are in the sound field, they behave as one entity. At our acoustic settings, it takes seconds to force the bubble clusters to positions approximately a quarter wavelength apart. It also just takes seconds to drive the clusters towards the capillary wall.Subjecting an ultrasound contrast agent of given concentration to a continuous low-amplitude signal makes it cluster to a microfoam of known position and known size, allowing for sonic manipulation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ultrasonics - Volume 50, Issue 2, February 2010, Pages 260–268
نویسندگان
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