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PublicationDNA barcoding of common Malaysia spiders using the Cytochrome Oxidase I (COI) gene(The Malaysian Society of Applied Biology, 2020)For the last twenty years, many newly described spiders were collected from Malaysia and in fact, more than 11,000 species were recorded in Peninsular Malaysia as well as in Sabah and Sarawak states. Scientists have put an immense effort on untangling the spider biology from its physical structure and behavior to silks and venoms. However, working with spiders is impeded by the difficulties in species identification via solely morphological methods. Thus, DNA barcoding is an alternative technique that employs standard fragment to facilitate species identification. Isolation of genomic DNA from three Malaysian spiders were performed using NucleoSpin® DNA insect extraction kit. Amplification of reference mitochondrial cytochrome oxidase I (COI) gene employing PCR with two set of primers followed by the DNA sequencing and validation through phylogenetic analysis were carried out. The commercial extraction kit was effective for the recovery of good quality of intact genomic DNA band as indicated by the integrity analysis. Both set of primers successfully amplified 100% of the samples with approximately 600 – 700 bp of PCR products. The obtained sequences (610 bp to 692 bp) were compared with the sequences available in Gene Bank. BLAST and phylogenetic analysis revealed that the analyzed individual samples belong to Nephila pilipes, Neoscona nautica and Crossopriza lyoni, respectively. Phylogenetic analysis provided unique insight into the evolutionary relationship of each analyzed sample. This study aids in an accurate identification of the selected local spider species at molecular level using the COI gene.
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PublicationToughening mechanism of thermoplastic starch nano-biocomposite with the hybrid of nanocellulose/nanobentonite(Elsevier, 2023)High flexibility and toughness are key criteria for an effective bioplastic packaging film. However, in most studies, the flexibility of thermoplastic starch (TPS) films is always neglected when targeting their tensile strength improvement. Low film flexibility has limited the development of TPS films in replacing the petrochemical-based plastic packaging films. In this communication, we report a method to produce thermoplastic corn starch (TPCS) films with excellent mechanical strength, high flexibility and high toughness through the hybridization of two natural nanofillers: nanobentonite and nanocellulose. The synergistic effect of the hybrid nanofillers can be observed through the arrangement of alternating nacre structures where the nanobentonite silicate layers are responsible for mechanical strength, while the nanocellulose promotes free volume in the TPCS matrix and triggers high film elongation at break. Structural, morphological, and thermomechanical analysis were conducted, and the detailed strengthening mechanism of the TPCS hybrid nano-biocomposite films was revealed.
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PublicationWettability of Sn-3.0Ag-0.5Cu solder reinforced with TiO₂ and Al₂O₃ nanoparticles at different reflow times(MDPI, 2023)This study investigated the influence of reinforcing 0.50 wt.% of titanium oxide (TiO₂) and aluminium oxide (Al₂O₃) nanoparticles on the wettability performance of a Sn-3.0Ag-0.5Cu (SAC305) solder alloy. The thermal properties of the SAC305 nanocomposite solder are comparable with thos of an SAC305 solder with a peak temperature window within a range of 240 to 250 °C. The wetting behaviour of the non-reinforced and reinforced SAC305 nanocomposite solder was determined and measured using the contact angle and spreading area and the relationships between them were studied. There is an increment in the spreading area (5.6 to 7.32 mm) by 30.71% and a reduction in the contact angle (26.3 to 18.6°) by 14.29% with an increasing reflow time up to 60 s when reinforcing SAC305 solder with 0.50 wt.% of TiO₂ and Al₂O₃ nanoparticles. The SAC305 nanocomposite solder has a better wetting performance compared with the SAC305 solder. As the reflow time increased, the spreading area increased and the contact angle decreased, which restricted intermetallic compound growth and thus improved wettability performance
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PublicationInfluence of TiO₂ and Al₂O₃ nanoparticles addition on thermal, wettability and IMC growth of Sn-3.0Ag-0.5Cu lead-free solder at different reflow temperature(Semarak Ilmu Publishing, 2023)This study investigated the influence of adding 0.50 wt% and 1.0 wt% titanium dioxide (TiO₂) and aluminium oxide (Al₂O₃) nanoparticles on the properties of Sn3.0Ag0.5Cu (SAC305) lead-free solder alloy. In terms of thermal properties, SAC305 lead-free solder with or without addition of TiO₂ and Al₂O₃ nanoparticles, the melting temperature is very similar and comparable. The wetting performance of the SAC305 nanocomposite solder was determined by the contact angle. The best contact angle recorded is 31.65° at reflow temperature of 250°C for 0.50 wt% addition of TiO₂ and Al₂O₃ nanoparticles. The thickness of the IMC layer was observed using an Optical Microscope and measured. Results show that the thickness of the IMC layer decreased when TiO2 and Al₂O₃ nanoparticles were reinforced into the SAC305 solder system, which shows significant decrease when 0.50wt% of TiO₂ and Al₂O₃ nanoparticles were added. However, beyond 0.50 wt% the thickness of IMC layer increases along with increasing reflow temperature. The results reveal that the adsorption effect of TiO₂ and Al₂O₃ nanoparticles will restrict the growth of the IMC layer under controlled concentration of the nanoparticles and reflow temperature. The optimal parameters to enhance the performance of SAC305 solder by reinforcing TiO2 and Al2O₃ nanoparticles are reflowed at 250°C at 0.50 wt% concentration of TiO₂ and Al₂O₃ nanoparticles.