Home > Press > Stirred, not shaken: Physicists gain more particle control
Abstract:
Cornell physicists can now precisely control how particles in viscous liquids swirl, twirl and whirl. Think of coffee and adding cream -- and gaining control of the particles in the cream. Understanding this concept could allow chemists, physicists and engineers to better detect molecules, control the mixture of nanoscale particles and enhance self-assembly in solutions.
Stirred, not shaken: Physicists gain more particle control
Ithaca, NY | Posted on March 21st, 2013
Brian Leahy, Cornell doctoral student in the field of physics, presented "Revisiting Taylor Dispersion: Differential Enhancement of Rotational and Translational Diffusion Under Oscillatory Shear" at the American Physical Society meeting, Baltimore, March 18. His co-researchers include: Xiang Cheng, physics postdoctoral researcher; Itai Cohen, professor of physics; and Desmond Ong '11.
If you stir, diffusion -- the random jostling of small particles from thermal energy -- is enhanced. This enhancement is called Taylor dispersion. "Stirring transports the cream through the coffee and also enhances diffusion of the cream particles," said Leahy.
Using 3-D imaging microscopes, the physicists can now also see the orientation of oblong particles in a viscous fluid, providing the ability to measure the individual particle rotation rates for the first time.
"By adding shear and adjusting the flow, particles can not only be oriented but their rotational diffusion can also change," said Leahy.
In a fluid, oblong particles that are small enough can change their orientation due to rotational diffusion that arises when fluid molecules kick the particles in random directions. When the particle-laden fluid is rubbed between two oscillating plates, the oblong particles also rotate end-on-end in what is known as a Jeffery's orbit.
The researchers showed that the combination of rotational diffusion and Jeffery orbits has an effect that is bigger than the so-called "sum of the parts," so that the particles change their orientation faster than either mechanism alone.
While this is basic, physical research, understanding these concepts could lead to opportunities in other fields, said Cohen: improved self-assembly of specially shaped particles, designer materials, or producing liquids with directional dependence that flow easily.
Leahy is supported by a National Defense Science and Engineering Graduate Fellowship.
####
For more information, please click here
Contacts:
Media Contact:
John Carberry
(607) 255-5553
Cornell Chronicle:
Blaine Friedlander
(607) 254-8093
Copyright © Cornell University
If you have a comment, please
Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Bookmark:
Physics
http://www.nanotech-now.com/news.cgi?story_id=47679 June 19th, 2013
Imaging
Beating the Diffraction Limit by 1000X – An introduction to nanoscale IR imaging on Bruker AFMs with applications in graphene June 19th, 2013
News and information
Less is More: Novel Cellulose Structure Requires Fewer Enzymes to Process Biomass to Fuel June 19th, 2013
Sound waves precisely position nanowires June 19th, 2013
Scientists Use Nanotechnology to Increase Thermal Stability of Essential Oils June 19th, 2013
Production of Bioactive Material for Quick Treatment of Bone Damages June 19th, 2013
Govt.-Legislation/Regulation/Funding/Policy
http://www.nanotech-now.com/news.cgi?story_id=47679 June 19th, 2013
A Battery Made of Wood? Wood fibers help nano-scale batteries keep their structure June 19th, 2013
Less is More: Novel Cellulose Structure Requires Fewer Enzymes to Process Biomass to Fuel June 19th, 2013
Sound waves precisely position nanowires June 19th, 2013
Self Assembly
Filmmaking magic with polymers June 12th, 2013
New microfluidic method expands toolbox for nanoparticle manipulation June 5th, 2013
Organic polymers show sunny potential: Rice, Penn State labs lay groundwork for block copolymer solar cells May 30th, 2013
Scientists at Tokyo Tech have developed a new self-assembled nanostructure that can survive very hot or saline environments May 27th, 2013
Discoveries
A Battery Made of Wood? Wood fibers help nano-scale batteries keep their structure June 19th, 2013
Less is More: Novel Cellulose Structure Requires Fewer Enzymes to Process Biomass to Fuel June 19th, 2013
Sound waves precisely position nanowires June 19th, 2013
Scientists Use Nanotechnology to Increase Thermal Stability of Essential Oils June 19th, 2013
Materials
A Battery Made of Wood? Wood fibers help nano-scale batteries keep their structure June 19th, 2013
Working backward: Computer-aided design of zeolite templates: Rice scientists apply drug-design lessons to production of industrial minerals June 17th, 2013
Discover the ‘Nanostructure Advantage’ at ECerS 2013, Booth 5: Innovnano presents nanostructured powders for high performance ceramics June 17th, 2013
Discovery of new material state counterintuitive to laws of physics June 14th, 2013
Announcements
Less is More: Novel Cellulose Structure Requires Fewer Enzymes to Process Biomass to Fuel June 19th, 2013
Sound waves precisely position nanowires June 19th, 2013
Scientists Use Nanotechnology to Increase Thermal Stability of Essential Oils June 19th, 2013
Production of Bioactive Material for Quick Treatment of Bone Damages June 19th, 2013
Tools
Beating the Diffraction Limit by 1000X – An introduction to nanoscale IR imaging on Bruker AFMs with applications in graphene June 19th, 2013
Nanometrics Announces Participation in 5th Annual CEO Investor Summit: Accredited Investor and Publishing Research Analyst Event to be Held Concurrently With SEMICON West and Intersolar 2013 in San Francisco June 19th, 2013
Beneq’s comprehensive industrial Thin Film Coating Services shorten time to market June 18th, 2013
Which qubit my dear? New method to distinguish between neighbouring quantum bits June 18th, 2013
Military
Unzipped nanotubes unlock potential for batteries: Rice University lab combines graphene nanoribbons with tin oxide for improved anodes June 13th, 2013
Polymer structures serve as 'nanoreactors' for nanocrystals with uniform sizes, shapes: Tiny chemistry June 11th, 2013
2-D electronics take a step forward: Rice, Oak Ridge labs make semiconducting films for atom-thick circuits June 10th, 2013
Noble way to low-cost fuel cells, halogenated graphene may replace expensive platinum June 6th, 2013