1. Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia, Italy
2. Materials Foundry (IOM-CNR), National Research Council, c/o Department of Physics and Geology, Via A. Pascoli, 06123 Perugia, Italy
3. Department of Civil and Environmental Engineering, University of Perugia, Strada di Pentima 4, 05100 Terni, Italy