Our collaborators and/or coinvestigators are as follows:

• Prof Svein Sunde, Department of Materials Science and Engineering, Norwegian University of Science and Technology, Trondheim, Norway
• Prof Frode Seland, Department of Materials Science and Engineering, Norwegian University of Science and Technology, Trondheim, Norway
• Prof Vijday Ramani, Mckelvey School of Engineering, Washington University in St. Louis, St. Louis, United States of America
• Prof Emanuela Carleschi, Department of Physics, University of Johannesburg, Johannesburg, South Africa
• Prof Bryan Doyle, Department of Physics, University of Johannesburg, Johannesburg, South Africa
• Dr Marcelle Potgieter, Netherlands Organisation for Applied Scientific Research (TNO), Alkmaar, Netherlands