Smallest whirlpools can pack stunningly st...( Researchers studying physical and chemi...)

Researchers studying physical and chemical processes at the smallest scales, smaller even than the width of a human hair, have found that fluid circulating in a microscopic whirlpool can reach radial acceleration more than a million times greater than gravity, or 1 million Gs.

By contrast, a pilot flying a fighter jet at high speed and in relatively tight circular patterns might experience a force of 10 to 12 Gs, making the force his body feels 10 to 12 times normal.

"From a physical perspective, it's not so surprising since the number of Gs goes up with an increase in velocity and the reduction in radius," said Daniel Chiu, a University of Washington assistant chemistry professor in whose laboratory the research was conducted.

What was surprising is just how much acceleration was achieved when the radius of the vortex the tight circular pattern in which tiny molecules were flying was reduced to such minute scales.

In this case, a tiny chamber one-third to one-half the width of a human hair was used to create a vortex in which less than a billionth of a liter of water reached an acceleration of more than 1 million Gs. The force was so strong that polystyrene beads a micron (1 millionth of a meter) in size, which the scientists were using to help visualize the flow of water, completely separated from the liquid in the vortex.

The finding by Chiu, doctoral student J. Patrick Shelby and research associates David Lim and Jason Kuo appears in the Sept. 4 edition of the journal Nature.

"It's just something neat that we stumbled upon," Chiu said. "You have a tiny volume of fluid and it is zipping around very rapidly."

The work, paid for by a grant from the National Science Foundation, could have future effects, as scientists and engineers explore microfluidics for a variety of applications. For instance, some researchers foresee a time when microfluidic systems can be used anywhere for quick analysis of biolo
'"/>

Contact: Vince Stricherz
vinces@u.washington.edu
206-543-2580
University of Washington
3-Sep-2003

Page: 1 2
Related biology news :

1. Smallest silicon particles light way for new sensors, materials
2. Scientists Discover Smallest Frog
3. When suns too strong, plankton make clouds
4. Triple-vaccine strategy stimulates strong HIV-specific immune response in monkeys
5. Clinical judgement still counts strongly alongside genetic testing
6. Food tastes stronger when youre hungry
7. Aspirin may not be strong enough to prevent clots in some heart patients
8. Experimental hantavirus vaccine elicits strong antibody response in primates
9. Ki-67 biomarker a strong predictor of outcome for prostate cancer patients
10. Expressing strong concern at human cloning reports, AAAS cautions against overreaction
11. Framingham heart study finds strong link between overweight/obesity & risk for heart failure