Research and Publications

 
 
 
Started in 1996, our collaborative work focused on studying
the physical properties of wet granular materials.
  
 
 
 
  1. I. Albert, P. Tegzes, B. Kahng, R. Albert, J. G. Sample, M. Pfeifer, A.-L. Barabási, T. Vicsek and P. Schiffer:
    Jamming and Fluctuations in Granular Drag.
    Phys. Rev. Lett,
  2. P. Tegzes, R. Albert, M. Paskvan, A.L. Barabási, T. Vicsek, P. Schiffer:
    Liquid Induced Transitions in Granular Media.
    Phys. Rev. E., 1999.
  3. R. Albert, M. Pfeifer, P. Schiffer, A.L. Barabási:
    Slow Drag in a Granular Medium.,
    Phys. Rev. Lett., 1999.
  4. A.L. Barabási, R. Albert, P. Schiffer, :
    Physics of Sandcastles: Effects of Controlled Wetness on the Angle of Maximum Stability of Granular Materials,
    Physica A, 1999.
  5. R.Albert, I. Albert, D. Hornbaker, P. Schiffer and A.L. Barabási:
    The maximum angle of stability in wet and dry spherical granular media.
    Phy. Rev. E, 1997.
  6. D.Hornbaker, R. Albert, I.Albert, A.L. Barabási, P. Schiffer:
    What keeps sandcastles up. ,
    Nature, 1997.
 
   
 
We have made the first well-controlled study of the addition of small quantities of liquid to a granular medium. We observe a dramaticincrease in the repose angle with a nanometer-scale layer of liquid on millimeter scale grains, as well as development o f long range correlations in the form of clumps.

D.Hornbaker, R. Albert, I.Albert, A.L. Barabási, P. Schiffer:
What keeps sand-castles up.
Nature 387, No 6635, (1997).

The artwork on the cover of Nature has been created by sandy feet, winner of the World Championship Sand Sculpture Competition 96'. We met her through a website maintained by her. The image of the sandcastle (built specifically for us ) can be downloaded by clicking on the image.

This paper has generated much interest in the scientific community as well as in the general public. Follow this link to see references to some of the related articles.
 
   
  R.Albert, I. Albert, D. Hornbaker, P. Schiffer and A.L.Barabási:
The maximum angle of stability in wet and dry spherical granular media..
Phy. Rev. E 56, 6271 (1997)

We demonstrate that stability criteria can be used to calculate the maximum angle of stability of a granular medium. Furthermore we determine the dependence of this angle on the liquid content of the material. We find good agreement between the theory and our experimental results.

 
   
  In the artice below we study an important property of granular materials, the analog of viscosity. We calculate the drag force acting on an object moving in a granular medium.

Réka Albert, Mark Pfeifer, Peter Schiffer, Albert-László Barabási:
Slow Drag in a Granular Medium.,
Phys. Rev. Lett. 82, 205, (1999).

 
   
  Albert-László, Réka Albert, Peter Schiffer, :
Physics of Sandcastles: Effects of Controlled Wetness on the Angle of Maximum Stability of Granular Materials,
Physica A 266, 340-345 (1999).
 		 
   
  P. Tegzes, R. Albert, M. Paskvan, A.L. Barabási, T. Vicsek, P. Schiffer:
Liquid Induced Transitions in Granular Media.
Phys. Rev. E. 60, 5823-5826 (1999).
 
   
  I. Albert, P. Tegzes, B. Kahng, R. Albert, J. G. Sample, M. Pfeifer, A.-L. Barabási, T. Vicsek and P. Schiffer:
Jamming and Fluctuations in Granular Drag.
Phys. Rev. Lett. 84, 5122-5125 (2000)
 		 
   

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Updated on July 26, 2000