1. Water Resources Research Center, The J. Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, 84990 Israel
2. Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, 84105 Israel
3. Applied Mechanics and Engineering Science Department, University of California, San Diego, La Jolla, CA 92093, USA