This study proposes general criteria to identify a radio quiet zone (RQZ) and a radio notification zone (RNZ) for the installation of a radio astronomical observatory on-site and safeguard the radio astronomy spectrum specifically in tropical regions. This study focuses on areas with a medium population density. Most RQZs selected in the world are mainly located in regions with a low population density, whereas this work studies the radio frequency interference (RFI) environment in humid tropical regions that have not been studied. The humidity in the tropical regions has a significant effect on radio signal, and this provides a unique perspective to the study. This study implements an algorithm to model the RFI level by considering important humidity factors. The ideal sites are chosen based on the RQZs criteria, whereas the realistic sites are based on the RNZs criteria. In Malaysia, four ideal and another four realistic candidate sites were identified, and the on-site RFI level measurement was conducted. From this study, Kuala Tembeling site is suggested as the RQZ and the Jelebu site as the RNZ in Malaysia.

Recently, Industrial Revolution 4.0 has highlighted the key components that will shift the world into digitalization; cybersecurity, cloud computing, mobile technologies, machine to machine, advanced robotics, big data, Internet of Things (IoT), RFID technology, cognitive computing and additive manufacturing. Additive manufacturing or better known as 3D printing technology has captivated many researchers due to its many advantages. This study aims to focus on the influence of temperature on the physical properties of the 3D printed structure made from poly(lactic) acid (PLA) with 100% infill. The highest Young’s modulus at the value of 4.42 GPa was obtained with a slight deviation under other samples exposed at the temperature of 70 °C and 80 °C. It was found that the ultimate tensile strength of the 3D printed structure when being exposed at the temperature of 80 °C for a maximized duration of 10 days while the breakage/fracture limit was recorded on samples after the 13rd day exposure at the same temperature. Meanwhile, the highest strain was achieved at 8.04% also during the 13rd day but at 70 °C. In conclusion, post-heat treatment has minimal effect on the Young’s modulus of 3D printed PLA but it was largely effecting the fracture limit of the structure. Therefore, heat treatment at temperature closed to the glass transition temperature of PLA polymer improved the adhesion strength between the printed layer thus enhancing the durability of the specimen under load conditions.