1. School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China e-mail:
2. School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-2088;
3. Environmental and Ecological Engineering, Purdue University, West Lafayette, IN 47907-2088 e-mail:
4. School of Mechanical Engineering, Shandong University, Jinan 250061, China;
5. Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Ministry of Education), Shandong University, Jinan 250061, China e-mail: