Numerical Simulation Analysis of Unfilled and Filled Reinforced Polypropylene on Thin-Walled Parts Formed Using the Injection-Moulding Process

Thin-walled moulding technology has attracted increasing attention, particularly in electronic packing applications. The injection moulding of shallow, thin-walled parts with a thickness of 0.7 mm was performed using three types of materials from polypropylene, PP (PP, PP + 50 wt% wood composite, and PP + 10 wt% glass fibre composite). The highest deflection resulting from PP + 50 wt% wood does not occur in the critical area of the thin-walled part compared with PP + 10 wt% glass fibre. In addition, the results revealed that the warpage at the midpoint of the part surface injected using PP + 50 wt% wood is 0.04 mm lower than the value of 0.08 mm obtained when injected using PP + 10 wt% glass fibre. The warpage was hypothesised to result from the residual stress caused by nonuniform volumetric shrinkages formed during the solidification phase

Metal concentration at surface water using multivariate analysis and human health risk assessment

This study defined the concentration of metals in Kerteh and Paka River water and their potential health risk towards human. 54 water samples were collected and analyzed using ICP-OES. Results revealed that most of the stations in Kerteh River gave the higher concentration of Cd, Cu, Zn, Co, Ni, As, Cr and Pb compared to Paka River. However As, Cr and Pb have exceeded the permissible limit of Malaysia standard for all stations in both rivers. Cd, Cu, Zn, Co and Ni were below than Malaysian standard permissible levels during the sampling period. The principal component analysis (PCA) revealed that both geogenic and anthropogenic sources were responsible to possible metals contamination in both rivers. Moreover, risk assessments for all metals were within the safe limits, except for As in the Kerteh River for both adult and child as well as to Paka River for both genders

Energy behavior assessment of rice husk fibres reinforced polymer composite

Natural fibre composites, possess characteristics that are beneficial towards the environment and ecosystem, completely biodegradable, renewable, offer strength and reliability of the material properties, and enhance economic development because of its ability in replacing synthetic composites. One of them refers to rice husk, which is a non-timber source that is easily available from agricultural wastes. Hence, rice husk fibres were selected as fibre-reinforced composites, while polypropylene as matrices in this research. Rice husk composite (RHC) specimens were produced via injection molding process. The composite composition was fixed at 35% of fibre content. The cycle tests were conducted to obtain cyclic properties by adhering to specifications outlined in ASTM D3479. Servo-hydraulic machines were used for five different stresses with constant amplitudes of R = 0.1, R = 0.3, and R = 0.5 of S75, S80, S85, S90, and S95 to determine the stress effects on energy dissipation and fatigue life of the material. The results indicated that there was increment in energy loss for the increasing fatigue life in every cycle. This shows that with the addition of natural fibres in composites, the material exhibited viscoelastic behaviour, in which energy loss was represented by matrix cracks and broken fibres