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Current issue

ELEKTRO 12/2017 was released on December 6th 2017. Its digital version will be available on January 5th 2018.

Topic: Measurement, measuring devices and engineering; Testing and diagnostics

Main Article
Measurements on rotating machines using SFRA method
Application possibilities of ultra-capacitors or LiFePO4 batteries in trolley network of the Brno Public Transit Company

SVĚTLO (Light) 6/2017 was released on December 11th 2017. Its digital version will be available on january 11th 2018.

Lighting installations
The lighting of university building Centrale Supélec in Saclay in France
The light for our future

Daylight
Application and judgment light guides Solatube®

Weird material shrinks when warm

14.10.2015 | UCONN | today.uconn.edu

Most materials swell when they warm, and shrink when they cool. But UConn physicist Jason Hancock has been investigating a substance that responds in reverse: it shrinks when it warms.

Although thermal expansion, and the cracking and warping that often result, are an everyday occurrence - in buildings, bridges, electronics, and almost anything else exposed to wide temperature swings - physicists have trouble explaining why solids behave that way.

New material shrinks when warm

Research by Hancock and his colleagues into scandium trifluoride, a material that has negative thermal expansion, recently published in Physical Review B, may lead to a better understanding of why materials change volume with temperature at all, with potential applications such as more durable electronics.

The classical way to think about solids like glass, metal, and rock imagines them made of atoms hooked together by springs. The springs stretch and flex in response to heat. But because each spring, when it expands, puts pressure on its neighboring springs - and all those neighboring springs expand the same amount and exert the same pressure on the first spring and all their own neighboring springs - the forces they exert on each other should be symmetrical, and the material should neither expand nor contract.

Read more at UCONN

Image Credit: UCONN

-jk-