1. National Research Council Canada, Energy, Mining and Environment Research Centre, 4250 Wesbrook Mall, Vancouver, British Columbia V6T 1W5, Canada
2. Natural Resources Canada, CanmetENERGY in Devon, One Oil Drive Patch, Devon, Alberta T9G 1A8, Canada
3. Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil