1. Department of Physics, State University of Ponta Grossa (UEPG), Avenue Carlos Cavalcanti 4748, 84.030-900 Ponta Grossa, PR, Brazil
2. Department of Soil Science, State University of Ponta Grossa (UEPG), Avenue Carlos Cavalcanti 4748, 84.030-900 Ponta Grossa, PR, Brazil