Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wandering heat: Anomalous heat distribution in one-dimensional systems

12.02.2014
According to Fourier’s law, heat spreads evenly throughout a system. For two- and one-dimensional objects such as films or the finest of wires, however, other rules seem to apply. NIM scientists have now pinned these down.

Just as ember spreads through a piece of coal, heat principally diffuses at a constant rate. The corresponding physical law known as Fourier’s law was already established 200 years ago.


Uniform spreading of heat ceases in low dimensions

Later, scientists came to the conclusion that other rules must apply to the distribution of heat in two- or one-dimensional objects such as films or very fine wires. Respective evidence was provided, for example, by experiments with carbon nanotubes or organic molecular chains, where thermal conductivity was not only dependent on the object’s material but also on its size, or rather its length.

This means that in some materials thermal conductivity increases with the object’s length, while in others it decreases. However, no one has so far been able to derive a physical law similar to Fourier’s law from these observations.

Together with international colleagues, NIM physicist Prof. Peter Hänggi (University of Augsburg) and his team have now gone one step further in the quest for such a law. The scientists have for the first time established a universally valid mathematical connection between object-size-dependent thermal conductivity and the corresponding anomalous rate of heat diffusion.

The insights thus gained allow scientists to devise hybrid materials which display entirely new thermal properties in one- or two-dimensional form. They exploit the fact that in these cases the rate of heat diffusion can be very high in some material compositions and extremely low in others. This is to say that one material allows heat to travel through it very quickly, while another functions as thermal insulator. The theoretical calculations are of particular interest for objects at nanoscale, whose thermal behavior is hard to measure in experiments. Currently, nanostructures composed of carbon materials which are to serve as phononic diodes or heat storage systems (memory) are simulated by computer models. Analogous to electronic components, these elements can then be used to conduct information processing.

“The exploration of heat diffusion in low-scale dimensions is only just beginning and certainly holds many surprises – as well as a huge potential”, explains Peter Hänggi. “The ubiquitous detrimental thermal losses, for example, can be used to beneficial effect for functional materials or phononic information processing. Maybe, in the distant future, the dream of a computer functioning with waste heat will come true.”

Publication:

Anomalous Heat Diffusion by Sha Liu, Peter Hänggi, Nianbei Li, Jie Ren, and Baowen Li. Phys. Rev. Lett. 112: 040601 (2014)

http://prl.aps.org/abstract/PRL/v112/i4/e040601

Contact person:

Prof. Peter Hänggi
Chair of Theoretical Physics I
Institute of Physics
University of Augsburg
86135 Augsburg, Germany
Tel: +49 821 598-3250
Hanggi@physik.uni-augsburg.de

Klaus P. Prem | idw
Further information:
http://www.nano-initiative-munich.de
http://www.uni-augsburg.de

More articles from Physics and Astronomy:

nachricht Hubble observes one-of-a-kind star nicknamed 'Nasty'
22.05.2015 | NASA/Goddard Space Flight Center

nachricht Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents
22.05.2015 | Universität Basel

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: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

Im Focus: First electrical car ferry in the world in operation in Norway now

  • Siemens delivers electric propulsion system and charging stations with lithium-ion batteries charged from hydro power
  • Ferry only uses 150 kilowatt hours (kWh) per route and reduces cost of fuel by 60 percent
  • Milestone on the road to operating emission-free ferries

The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...

Im Focus: Into the ice – RV Polarstern opens the arctic season by setting course for Spitsbergen

On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.

RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...

Im Focus: Gel filled with nanosponges cleans up MRSA infections

Nanoengineers at the University of California, San Diego developed a gel filled with toxin-absorbing nanosponges that could lead to an effective treatment for skin and wound infections caused by MRSA (methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria. This "nanosponge-hydrogel" minimized the growth of skin lesions on mice infected with MRSA - without the use of antibiotics. The researchers recently published their findings online in Advanced Materials.

To make the nanosponge-hydrogel, the team mixed nanosponges, which are nanoparticles that absorb dangerous toxins produced by MRSA, E. coli and other...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Mesoporous Particles for the Development of Drug Delivery System Safe to Human Bodies

22.05.2015 | Materials Sciences

Computing at the Speed of Light

22.05.2015 | Information Technology

Development of Gold Nanoparticles That Control Osteogenic Differentiation of Stem Cells

22.05.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>