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PublicationEnergy behavior assessment of rice husk fibres reinforced polymer composite(Elsevier, 2020)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.
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PublicationOptimization of multi factors for injection-moulded micro gear via numerical simulation integrated with the taguchi method and principal component analysis(Penerbit Universiti Teknikal Malaysia Melaka, 2020-08-28)Many factors need to be considered in producing micro gear by means of injection moulding process including material selection, part and mould design as well as processing parameters. Inappropriate combination of these factors can cause numerous production problems such as occurring of defects, long lead time, much scrap and high production cost. Therefore, the aim of this study is to evaluate the effects of different material for micro gear, gate types, size of gear as well as processing parameters on the multi quality characteristics of the micro gear. The simulation was conducted by integration of Taguchi L27 orthogonal array and principal component analysis. The result of main effect analysis exhibited that the optimal combination of factors that resulted in minimum sink index, volumetric shrinkage and deflection was A3B3C2D3E1F1G1H1I3. Meanwhile, from the ANOVA, gate type was found out to be the most significant factor in minimizing the multi quality characteristic of the simulated micro gear. The findings of this study should be benefited to the gear industry particularly in improving the quality of micro gear where the use of micro gear in microsystem is accelerating nowadays.
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PublicationTailoring polylactic acid properties for packaging applications: effects of co‐addition of halloysite nanotubes and selected plasticizers(Trans Tech Publications Ltd., 2020)Polylactic acid (PLA) has recently given a huge attention because of its mechanical properties and good physical like good biodegradability and processability, high tensile modulus and strength. In the current research, the researchers utilized sesame oil (SO) and low molecular weight polyethylene glycol (PEG) as hydrophobic and hydrophilic plasticizers, towards improvise the ductility and toughness of PLA. The researchers synthesized nanocomposites by solution casting of the neat PLA/HNTs and PLA blends with weight ratio of (0,10, 20 and 30 wt%) for PEG and (0, 5 and 10 wt%) for SO. The influence of both plasticizers on chemical, thermal and mechanical properties of the nanocomposites were investigated. Characterization of the systems was achieved by mechanical testing and thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR). The FTIR analyses confirmed the existing of hydrogen bonding between PLA and both PEG and SO. significant improvement was shown by the plasticized nanocomposites in elongation at break with the adding of PEG and SO, meanwhile, the plasticized films’ strength were decreased. For the thermal analyses, all the films exhibited lower thermal stability compared to PLA/HNTs film.
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PublicationInvestigation of mechanical, physical and durability properties of metakaolin-based geopolymer(Polish Academy of Sciences, 2023)Due to their potential to lower CO2 emissions linked with the cement and concrete industries, geopolymer binders are a desirable alternative for Portland cement binders. However, if they are to become a viable alternative to conventional Portland cement materials, their resilience in harsh conditions has to be further investigated. This paper presented mechanical and short-term durability properties of metakaolin based geopolymer concrete at sulphuric acid (H2SO4) solutions exposed with the concentrations of 2%, 3%, 4% and 5% for 14 days. (0%) or unexposed sample also prepared as referral and comparison. The geopolymer concretes were synthesized using an alkali activation of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The main objective of the study was to examine the durability and deterioration mechanism parameters like different acid percentages, changes in weight, compressive strength, density and water absorption. Morphology analysis also performed in this study. The results indicated that metakaolin geopolymer experienced some strength deterioration with increasing sulphuric concentration solutions which are from 32.58 MPa, 20.67 MPa and 4.25 MPa at unexposed (0%), 2% and 5% sulphuric acid immersion respectively. Furthermore, change in weight or mass loss and water absorption after the chemical attack resulted directly proportional to sulphuric acid concentration due to increment of crack on the sample. Among that, the metakaolin geopolymer submerged in 2% acid gives the optimum results in terms of durability, mechanical and physical qualities.
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PublicationInvestigation on young adult hand grip strength(Malaysian Public Health Physicians’ Association, 2020-08-01)It is believed that exposure to whole-body vibration (WBV) may increase seated occupant drowsiness and seated. The purpose of this paper is to investigate the strength of the hand grip among the young adults in Malaysia. Also, to examine the correlation between anthropometry factors such as hand length (HL), hand breadth (HB), wrist circumference (WC) and body mass index (BMI) with average full hand grip strength of young adults. 40 Malaysian young adults with equal females and males and the range age of 23 to 28 years old voluntarily basis participated in this study. Three experiments were conducted in sitting position according to American Standard Hand Therapist (ASHT) with 45º, 90o and 135o of hand flexion using dynamometer. The results show the significant different full hand grip strength between Malaysian young adult females and females, the difference full hand grip strength for different hand flexion angles in sitting position and difference correlations between anthropometry factors and full hand grip strength for both young adult males and females.