Navigation Links
Why anyone can make a sandcastle
Date:2/11/2008

This release is available in German.

Anyone trying to build sandcastles on the beach will need some degree of skill and imagination, but not an instruction manual. The water content is actually relatively unimportant to the mechanical properties of the sand. This observation, which is borne out by precise measurements in the laboratory, puzzles researchers. Even with water content of just 3%, the fluid inside represents a highly-complex structure. The mechanical stiffness of the wet sand remains practically constant with moisture ranging from less than 1% to well over 10%, although the fluid structure changes enormously internally. Researchers at the Max Planck Institute for Dynamics and Self-Organisation in Gttingen, the Australia National University in Canberra, the University of Erlangen, and the ESRF in Grenoble have studied the fluid structures in moist granules using x-ray microtomography to discover their laws (Nature Materials, online publication of February 10, 2008).

In medicine, x-ray microtomography is also known as computer tomography. Scientists x-ray an object from various angles to produce an outline image similar to a standard x-ray. A computer evaluates all of these images and determines which kind of three-dimensional structure the object must have to produce the outline images. When scientists use a bright x-ray source, such as the synchrotron source of radiation at the ESRF in Grenoble, computer tomography is produced with a resolution of thousandths of a millimetre. That is sufficient to resolve the tiny, highly-complex fluid structures that form in a moist granule, like inside a sandcastle for example.

What the research team saw was initially quite astonishing. The fluid did not fully push through the granulate structure and therefore did not force the air out of the interstitial space. More significantly, a filigree structure emerged in which the fluid, grains and air existed equally side by side. The reason for this is easy to understand. As the fluid moistens the grains (it would not otherwise be possible to get them into the granule), it tries to surround itself with as much "grain" as possible. This is best achieved at the points of contact where two grains touch. The "empty" space in between is relatively unattractive for the fluid and fills with air.

When the Gttingen scientists then carried out a more exact study of the geometry of these filigree fluid structures, they established that not only did they all have the same pressure, but that the pressure had to be independent of the fluid content. This explains the universal stiffness of the material. The equal pressure corresponds to an equal force inside and therefore results in the moist granules having the same mechanical properties. "These properties are not only significant to the building of sandcastles," said Stephan Herminghaus, the head of the study. "They are relevant to the pharmaceutical and food-production industries and help us to understand certain natural catastrophes, such as landslides. Wet granules are relevant in many fields and we now have a better understanding of their mechanical properties."


'/>"/>

Contact: Professor Dr. Ralf Seemann
ralf.seemann@ds.mpg.de
49-551-517-6220
Max-Planck-Gesellschaft
Source:Eurekalert  

Related medicine news :

1. Anyone can save a life: Penn researchers lead national efforts to improve CPR quality
2. Hepatitis C Testing Recommended for Anyone with a Tattoo
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Why anyone can make a sandcastle
(Date:3/27/2017)... IL (PRWEB) , ... March 27, 2017 , ... ... systems, recently received the CE Certificate of Conformity for the Smart System® 20/20. ... or exceed the highest industry standards and specifications such as ANSI, ISO and ...
(Date:3/27/2017)... PA (PRWEB) , ... March 27, 2017 , ... ... business simulation -centric training, today announced the launch of a new research ... strategy, having the skills needed to execute that strategy, and the actual success ...
(Date:3/27/2017)... ... 2017 , ... According to the American Cancer Society , the average ... 95%. Once the cancer spreads to other organs, bones, or lymph nodes, however, the ... avoid this latter group, tune in to Lifestyle Magazine on April 9, ...
(Date:3/27/2017)... ... March 27, 2017 , ... ... facility from 8:00am-10:00am on Monday, April 3rd to commemorate the two-year anniversary of ... opportunity for area-residents to celebrate two great years while also familiarizing themselves with ...
(Date:3/25/2017)... ... March 25, 2017 , ... Getting earned media coverage meaningful ... partner. , All through the year, Garden Media aims to provide material helpful ... key influencers and pitching client’s key messages to gain coveted media placements, ...
Breaking Medicine News(10 mins):
(Date:3/27/2017)... 2017 BioLineRx Ltd. (NASDAQ/TASE: BLRX), a ... that AGI-134, an immunotherapy for the treatment of multiple cancers, ... be featured at the upcoming American Association for Cancer ... to be held on April 1-5, 2017. ... An abstract ...
(Date:3/27/2017)... 2017 The global clinical ... billion by 2025, according to a new study by ... diseases is anticipated to be responsible for the high ... the scope for growth during the forecast period. In ... is highly susceptible to chronic diseases, is presumed to ...
(Date:3/27/2017)... March 27, 2017  Impax Laboratories, Inc. (NASDAQ: IPXL)today ... Paul M. Bisaro as Impax,s President and Chief ... effective March 27, 2017. Mr. Bisaro will succeed ... President and Chief Executive Officer since December of 2016. ... branded pharmaceutical experience, Mr. Bisaro, 56, is an accomplished ...
Breaking Medicine Technology: