Imaging Microbubbles. Antony Hsu Shanti Bansal Daniel Handwerker Richard Lee Cory Piette. Topics of Discussion. Brownian Motion What are these bubbles and why do we use them? Following the Great Perrin - Diffusion and Gravitational Motion of Microbubbles Optical Imaging of Microbubbles.
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Air or High Molecular
Left Arrow: Lipid-Coated Microbubble
Right Arrow: Saline Microbubble
Enveloped by a shell (proteins, fatty acid esters).
Exist - For a limited time only! 4 minutes-24 hours; gases diffuse into liquid medium after use.
Size varies according to Ideal Gas Law (PV=nRT) and thickness of shell.We’re all about Microbubbles (5)
Following Perrin, we look at the characteristic length (lambda) which will tell us about the motion of the bubble.
F G = -c(x,t)How Bubbles Separate
FT = FD + FG
rp = density of particle
rw = density of water(1g/cm3)
r = radius of bubble(cm)
meff = (4/3) p r3 (rp - rw)How Bubbles Separate(2)
K =Boltzman’s constant (1.38x10-23 J/K)
T = Temperature in Kelvin (300K)
g = gravity(9.81 m/s2)
meff = effective mass
The size of of microbubbles is known(1-7mm). Therefore, the only factor to be determined is the density of the microbubble.
With gas-filled bubbles, the thickness and density of the shell gives the bubble its mass.
Well, we want a bubble that will not “float” or “sink.”
By adjusting the shell thickness to the force of gravity,
we can achieve “neutral buoyancy.”
He conducted experiments to examine diffusion through emulsions
He built used a light microscope to visualize emulsions at different depths
Perrin determined depth of pictures by the following formula: H=CH’. C = relative refractive index of the two media which the cover-glass separates. H’ = height of microscope.Perrin’s light microscope