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Submitted on: 08 December 2009.
Revised on: 02 February 2010.
Accepted on: 25 March 2010.
___________________INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
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Submitted on: 19 May 2006.
Revised on: 07 August 2006.
Accepted on: 28 August 2006.
___________________INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
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