1. TADRUS Research Group, Department of Agricultural and Forestry Engineering, University of Valladolid, 34004 Palencia, Spain
2. International Department, Harper Adams University, Newport TF10 8NB, UK
3. Engineering of Manufacturing Processes Group, School of Industrial Engineering, University of Valladolid, 47002 Valladolid, Spain
4. TADRUS Research Group, Department of Agroforestry Sciences, University of Valladolid, 34004 Palencia, Spain