Environmentally safe magnetic nanocatalyst for the production of biodiesel from Pongamia pinnata oil by Sami, Hafiza Qurat ul Ain, Hanif, Muhammad Asif, Rashid, Umer, Nisar, Shafaq, Bhatti, Ijaz Ahmad, Rokhum, Samuel Lalthazuala, Tsubota, Toshiki, Alsalme, Ali