Prof. Dr. Eng. Ir. Didik Nurhadiyanto, ST., MT., IPU, ASEAN Eng. gave a public lecture in front of the staff and students of the Undergraduate, Masters and Doctoral Degree Department of Mining and Metallurgical Institute, Satbayev University, Kazakhstan. Prof. Didik Nurhadiyanto gave material in public lectures on two topics. The first topic is the 'Development of Corrugated Metal Gaskets for Pipe-to-Pipe Joints'. In contrast, the second topic is 'Development of Composite Hybrid Ramie Fiber Reinforced Epoxy (RFRE)-Tungsten Carbide, Ceramic SiC, and Hardened Steel as Bulletproof Panel NIJ Standard '.

"Asbestos gaskets have the advantage of preventing leaks, but asbestos contains chemicals that are very dangerous and cause serious health problems. In Japan, the use of asbestos has been banned since 2008. Asbestos gasket replacements are available but are expensive, have lower performance and use less time. The need for asbestos replacement gaskets is urgent," said Prof. Didik Nurhadiyanto.

One of the ideas for developing safer gaskets is the development of corrugated metal gaskets made from SUS304 as a substitute for asbestos materials that have been banned for use and production. "Corrugated metal gaskets are made of two waves at the top and bottom to minimize the tightening force on the bolts and provide a spring effect so that the bolts do not loosen," he said on Tuesday (10/1). Corrugated metal gaskets are also developed by coating SUS304 material with nickel or copper through electroplating. Currently, corrugated metal gaskets are used in several industries.

Related to the second topic, Prof. Didik Nurhadiyanto presented the potential for developing bullet-proof panels made from hemp fibre (boehmeria nivea) which is considered more environmentally friendly and cheaper than bullet-resistant fibres made from kevlar and ceramics. "Hemp fibre has excellent mechanical properties, namely 849MPa tensile strength and 16MPa firmness. However, hemp fibre is relatively less effective in holding bullet sharpness," said Prof. Educate Nurhadiyanto. To solve this problem, hemp fibre bullet panels require two layers. For the first strike layer, the material used must break the bullet material. The rupture of the bullet material will blunt the bullet, and then the shell will be entangled by hemp fibre which functions as a second layer. (Author : Didik; Editor : Dedy; Tj.Lak)