100 years after Einstein’s landmark work on Brownian motion, physicists have discovered a new concept of temperature that could be the key to explaining how ice and snow particles flow during an avalanche, and could also lead to a better way of handling tablets in the pharmaceutical industry. This research is reported today in a special Einstein Year issue of the New Journal of Physics (www.njp.org) published jointly by the Institute of Physics and the German Physical Society (Deutsche Physikalische Gesellschaft).
Everything from powdery snow to desert sands, from salt to corn flakes are granular materials. Physicists have known for many years that granular materials have many perplexing properties that make them behave at times like solids, liquids, and even gases. This new research reveals for the first time how to measure a concept called “granular temperature” – that could be the key to explaining how they behave. “Take the solid snow covering a ski slope, for instance”, suggests lead author of the paper Patrick Mayor of the EPFL in Lausanne, Switzerland. “While it stays still it is a solid, but as soon as it starts flowing downhill as happens during an avalanche the flowing material is behaving more like a liquid. Similarly, during a desert storm, sand grains are whipped up and behave like molecules in a gas, rather than as a solid”.
"Whereas most materials are usually described as solid, liquid or gases, granular systems do not seem to fall into any of these categories and are often considered a separate state of matter of their own," says Mayor, "The diverse behaviour of granular materials makes it extremely difficult to establish a general theory that accounts for the observed phenomena." Mayor and his colleagues, Gianfranco DAnna, Alain Barrat, Vittorio Loreto, have shown that shaken granular matter behaves in a way related to Einsteins theory of Brownian motion, first published in 1905.
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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