1. Valvoline New Product Development Laboratory, Ashland Consumer Markets, Lexington, KY 40509, US (Corresponding author), e-mail: gwu@ashland.com
2. Valvoline New Product Development Laboratory, Ashland Consumer Markets, Lexington, KY 40509, US.
3. Tank Automotive Research, Development and Engineering Center, U.S. Army, Warren, MI 48092, US.