1. Postgraduate Researcher, Univ. of Surrey, Guildford GU2 7XH, U.K.; also, Research Assistant, Mechanical Engineering Dept., Imperial College, Exhibition Rd., London SW7 2AZ, U.K.
2. Research Assistant, Mechanical Engineering Dept., Imperial College, Exhibition Rd., London SW7 2AZ, U.K.
3. Senior Lecturer, Mechanical Engineering Dept., Imperial College, Exhibition Rd., London SW7 2AZ, U.K.
4. Professor of Energy and Environmental Systems, Centre for Environmental Strategy, Univ. of Surrey, Guildford GU2 7XH, U.K.