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Submitted on: 29 March 2000.
Revised on: 09 July 2000.
Accepted on: 25 July 2000.
___________________IETE TECHNICAL REVIEW---TAYLOR & FRANCIS LTD
Submitted on: 15 November 1998.
Revised on: 30 December 1998.
Accepted on: 21 January 1999.
___________________IETE TECHNICAL REVIEW---TAYLOR & FRANCIS LTD