c 2010 Published by Elsevier Ltd. Procedia Engineering 5 (2010) 588–591 www.elsevier.com/locate/procedia 1877-7058 c 2010 Published by Elsevier Ltd. doi:10.1016/j.proeng.2010.09.178 Open access under CC BY-NC-ND license. Open access under CC BY-NC-ND license.