Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What sponges, beards and the lung have in common

21.08.2009
Max Planck mathematicians and their colleagues in Poland developed a novel criterion for the calculation of mass and energy transport in porous systems

Porous media are ubiquitous.

The sponge in the kitchen, the lung tissue, the human skin, all of them are porous. They are full of holes like a Swiss cheese and they have remarkable properties due to their structure.

Mathematicians from the Max Planck Institute for Marine Microbiology in Bremen and their colleagues from the University of Wroclaw in Poland took a close look at the characteristics of perforated matter and defined a novel criterion for the homogeneity of these systems. According to their findings a large number of old model calculations published so far do not meet this standard and are inaccurate.

Not only pure academic curiosity is the reason that scientists are interested in the mathematics of these strange materials. In nature porous surfaces are involved in the decomposition of chemical compounds and natural products. Marine aggregates in the oceans take part in the release of carbon dioxide. Today's modern industry is seeking for new technology in hydrology, oil and gas production, in textile engineering and many more applications. The calculations of heat and mass transfer through porous systems are still a challenge in process engineering. How fluids and gases flow through complex channels is a demanding task for science and engineering. The systems under consideration may be very large like the continental shelf from which almost half is made of permeable sands.

Prof. Dr. Arzhang Khalili from the Max Planck Institute for Marine Microbiology in Bremen poses the crucial question:" What is the minimum size of the model system in order to be able to predict the behavior of the particles in the real world?" The underlying basic assumption is that the porous material has to be homogeneous. Large model systems demand high computational power and therefore the systems were kept as small as possible. With many intensive numerical calculations Arzhang Khalili and his polish colleagues Zbigniew Koza and Maciej Matyka proved that most model systems published in the scientific literature were too small. " The size of the model system must be at least 100 times larger than the mean grain size. We checked old publications dating back 17 years and found that the majority of them did not fulfill this standard. According to our study almost all of them have to be recalculated", states Professor Khalili.

Manfred Schlösser

For more information please contact
Prof. Dr. Arzhang Khalili
+49 421 2028636
E-Mail akhalili@mpi-bremen.de
or the press officers
Dr. Manfred Schloesser +49 421 2028704 mschloes@mpi-bremen.de
Dr. Susanne Borgwardt +49 421 2028704 sborgwar@mpi-bremen.de
Original publication
Koza, Z. Matyka, M, & Khalili, A. (2009): Finite-size anisotropy in statistically uniform porous media. Phys. Rev. E. 79. 066306-1 - 066306-7.

Dr. Manfred Schloesser | idw
Further information:
http://www.mpi-bremen.de

More articles from Earth Sciences:

nachricht New plate adds plot twist to ancient tectonic tale
15.08.2017 | Rice University

nachricht Global warming will leave different fingerprints on global subtropical anticyclones
14.08.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>