1. Department of Thermo and Fluid Dynamics, Chalmers University of Technology, S-412 96 Gothenburg, Sweden; Department of Work Organization and Technology, National Institute for Working Life, S-171 84 Solna, Sweden
2. Department of Thermo and Fluid Dynamics, Chalmers University of Technology, S-412 96 Gothenburg, Sweden
3. Department of Work Organization and Technology, National Institute for Working Life, S-171 84 Solna, Sweden