Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Acoustic levitation made simple

05.01.2015

Ultrasonic device made by Brazilian team to be featured on the cover of Applied Physics Letters this week

A team of researchers at the University of São Paulo in Brazil has developed a new levitation device that can hover a tiny object with more control than any instrument that has come before.


This shows levitation of expanded polystyrene particles and the simulated standing wave pattern.

Credit: M. Andrade/University of São Paulo

Featured on this week's cover of the journal Applied Physics Letters, from AIP Publishing, the device can levitate polystyrene particles by reflecting sound waves from a source above off a concave reflector below. Changing the orientation of the reflector allow the hovering particle to be moved around.

Other researchers have built similar devices in the past, but they always required a precise setup where the sound source and reflector were at fixed "resonant" distances. This made controlling the levitating objects difficult. The new device shows that it is possible to build a "non-resonant" levitation device -- one that does not require a fixed separation distance between the source and the reflector.

This breakthrough may be an important step toward building larger devices that could be used to handle hazardous materials, chemically-sensitive materials like pharmaceuticals -- or to provide technology for a new generation of high-tech, gee-whiz children's toys.

"Modern factories have hundreds of robots to move parts from one place to another," said Marco Aurélio Brizzotti Andrade, who led the research. "Why not try to do the same without touching the parts to be transported?"

The device Andrade and his colleagues devised was only able to levitate light particles (they tested it polystyrene blobs about 3 mm across). "The next step is to improve the device to levitate heavier materials," he said.

How the Acoustic Levitation Device Works

In recent years, there has been significant progress in the manipulation of small particles by acoustic levitation methods, Andrade said.

In a typical setup, an upper cylinder will emit high-frequency sound waves that, when they hit the bottom, concave part of the device, are reflected back. The reflected waves interact with newly emitted waves, producing what are known as standing waves, which have minimum acoustic pressure points (or nodes), and if the acoustical pressure at these nodes is strong enough, it can counteract the force of gravity and allow an object to float.

The first successful acoustical levitators could successfully trap small particles in a fixed position, but new advances in the past year or so have allowed researchers not only to trap but also to transport particles through short distances in space.

These were sorely won victories, however. In every levitation device made to date, the distance between the sound emitter and the reflector had to be carefully calibrated to achieve resonance before any levitation could occur. This meant that the separation distance had to be equal to a multiple of the half-wavelength of the sound waves. If this separation distance were changed even slightly, the standing wave pattern would be destroyed and the levitation would be lost.

The new levitation device does not require such a precise separation before operation. In fact, the distance between the sound emitter and the reflector can be continually changed in mid-flight without affecting the levitation performance at all, Andrade said.

"Just turn the levitator on and it is ready," Andrade said.

###

The article, "Particle manipulation by a non-resonant acoustic levitator" is authored by Marco A. B. Andrade, Nicolás Pérez and Julio C. Adamowski. It appears in the journal Applied Physics Letters on Monday, January 5, 2015 (DOI: 10.1063/1.4905130). After that date, it will be available at: http://scitation.aip.org/content/aip/journal/apl/106/1/10.1063/1.4905130

The authors of this paper are affiliated with the University of São Paulo in Brazil and Universidad de la República in Uruguay.

ABOUT THE JOURNAL

Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See: http://apl.aip.org

Jason Socrates Bardi | EurekAlert!

More articles from Physics and Astronomy:

nachricht When AI and optoelectronics meet: Researchers take control of light properties
20.11.2018 | Institut national de la recherche scientifique - INRS

nachricht How to melt gold at room temperature
20.11.2018 | Chalmers University of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Nonstop Tranport of Cargo in Nanomachines

20.11.2018 | Life Sciences

Researchers find social cultures in chimpanzees

20.11.2018 | Life Sciences

When AI and optoelectronics meet: Researchers take control of light properties

20.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>