Surface roughness and the sensitivity of D-shaped optical fibre sensors by Qazi, Hummad Habib, Memon, Sanober Farheen, Ali, Muhammad Mahmood, Irshad, Muhammad Sultan, Ehsan, Siddique Akhtar, Salim, Mohd. Rashidi, Mohammad, Abu Bakar, Zulkifli, Mohd. Zamani, Muhammad Idrees, Muhammad Idrees