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ELEKTRO 10/2017 was released on October 10th 2017. Its digital version will be available on October 10th 2017.

Topic: Electrical power engineering; RES; Fuel cells; Batteries and accumulators

Main Article
Electricity storage
Electrochemical impedance spectroscopy of batteries

SVĚTLO (Light) 5/2017 was released on September 18th 2017. Its digital version will be available on September 18th 2017.

Luminaires and luminous apparatuses
MAYBE STYLE introducing LED design luminaires of German producer Lightnet
TREVOS – new luminaires for industry and offices
How many types of LED panels produces MODUS?
Intelligent LED luminaire RENO PROFI

Interiors lighting
The light in indoor flat interior – questions and answers

Researchers Control Surface Tension to Manipulate Liquid Metals

14.09.2015 | NCSU | news.ncsu.edu

Researchers from North Carolina State University have developed a technique for controlling the surface tension of liquid metals by applying very low voltages, opening the door to a new generation of reconfigurable electronic circuits, antennas and other technologies.

The technique hinges on the fact that the oxide “skin” of the metal - which can be deposited or removed - acts as a surfactant, lowering the surface tension between the metal and the surrounding fluid. The researchers used a liquid metal alloy of gallium and indium. In base, the bare alloy has a remarkably high surface tension of about 500 millinewtons (mN)/meter, which causes the metal to bead up into a spherical blob.

Manipulating the liquid metal

“But we discovered that applying a small, positive charge - less than 1 volt - causes an electrochemical reaction that creates an oxide layer on the surface of the metal, dramatically lowering the surface tension from 500 mN/meter to around 2 mN/meter,” says Dr. Michael Dickey, an associate professor of chemical and biomolecular engineering at NC State and senior author of a paper describing the work. “This change allows the liquid metal to spread out like a pancake, due to gravity.”

The researchers also showed that the change in surface tension is reversible. If researchers flip the polarity of the charge from positive to negative, the oxide is eliminated and high surface tension is restored. The surface tension can be tuned between these two extremes by varying the voltage in small steps.

Read more at NCSU

Image Credit: NCSU

-jk-