Advanced Materials Research Vol. 795

Abstract: The biocomposites were prepared by using kenaf bast fiber mat as reinforcing materials at different percentage. The kenaf bast fiber was treated with alkaline at different sodium hydroxide (NaOH) percentage. From the results obtained, surface morphology of the treated kenaf bast fiber shows less impurity than untreated kenaf bast fiber. As for composites prepared from alkaline treated kenaf bast fiber, it showed higher mechanical properties as compared to those prepared from untreated kenaf bast fiber. The percentage of kenaf fiber in composites also plays a crucial role in determining the composite properties.

Abstract: This project is focused on the production of wollastonite (CaSiO3) from local resources. Wollastonite was produced by milling silica (SiO2) and limestone (CaCO3) in planetary mill for 1 and 5 hours. Samples have been sintered at different temperatures which are 900oC, 1100oC and 1300oC for 1 hour. The raw materials that have been used was collected from surround of state of Perlis and have high purity. This has been proven by X-Ray Fluorescence (XRF) analysis. By observing under Scanning Electron Microscope (SEM), the morphology of wollastonite shows that it has high porosity and disperses homogeneously. The X-Ray Diffraction (XRD) pattern shows that the phase of β wollastonite occurred almost at high temperature which is 1100oC. Besides, the intensity of peak also shows that the wollastonite has crystalline structure. The C-O and C-C bonding is proven by Fourier Transform Infra-Red (FTIR) analysis. The particle size for 1h milling is 26.16μm while for 5h is 16.8 μm.

Abstract: Fresnoite with composition Ba₂TiSi₂O₈ (B₂TS₂) was first found in 1965, adopting a non-centrosymmetric structure. It also reported to crystallize in a tetragonal unit cell with a=8.52Å and c=5.210Å leading to some possible application as hydrophone, transducer and second harmonic generation and low temperature co-fired ceramics (LTCC). B₂TS₂ were synthesized by conventional solid state reaction. Phase pure B₂TS₂ was obtained after heating the pellets at a final sintering temperature of 1230 °C in air at 92 h. Study found that Fresnoite B₂TS₂ is a type of materials which are not ferroelectric and instead show perfect dielectric insulator behaviour with resistance >10⁶Ωcm at temperatures below 750°C and also shows nonideal debye respone. The activation energy for conduction of B₂TS₂ samples is very high, indicating that these materials are highly insulating.

Abstract: Global demand for plastics has grown significantly over the past decades, and will continue to expand with rising income levels in emerging economies; a number of approaches have been used to recycle polymer waste. While chemical recycling is one of the key methods used as it recovers and reuses the polymer in high-end product; new avenues for waste recycling need to be developed. In-depth interfacial behaviour investigation was carried out to study interactions between polymers and petroleum coke (PC). Polypropylene (PP), polyethylene (PE) and polystyrene (PS) polymers are three major polymers that abundantly found in waste streams were chosen and their properties and the effect of petroleum coke presence on the degradation process of polymer have been characterized. The polymer was mixed and homogenized prior pyrolysis up to 600C. The residues yield after pyrolysis was collected and analyzed.

Abstract: In this study, anodic aluminum oxide (AAO) fabricated from phosphoric acid electrolyte at ambient temperature was used as the porous template, while a sol gel procedure was used for the preparation of the TiO₂ sol with the addition of 0.1, 0.3, and 0.5 g of polyethylene glycol (PEG). The addition of PEG to the TiO₂ sol prevents surface cracks and improves the adhesion of the sol to the template to produce different surface morphologies which were visible under the scanning electron microscope (SEM). Although, complete degradation of the methyl orange (MO) dye was not achieved initially with the TiO₂ coated template, until an oxidizer in the form of H₂O₂ with different concentrations of 0.029M, 0.088M, and 0.147M were added during the photocatalysis process to shorten the degradation time and to ensure complete mineralization of the MO dye.

Abstract: Anodic aluminium oxide fabricated at ambient temperature and low potential in phosphoric acid electrolyte was used as the working electrode for the electrochemical measurement of phosphate buffer saline under different pH conditions using the cyclic voltammetry tool. We investigate the reversibility of the electrochemical reaction as a redox reaction from the cyclic graphs that were obtained. We observed that the ratio of the peak current passed at both the reduction and oxidation when measured was very close to unity in all the pH but except one which produced a none reversible reaction with a non cyclic graph. The peak potential for both reduction and oxidation reactions using phosphate buffer saline as the analyte under different pH of 3, 5, 7, and 9 was also obtained.

Abstract: First ferroelectric materials were found in Rochelle salt was in a perovskite structure. Lead Magnesium Niobate (PMN) is a perovskites with a formula of PbMg_1/3Nb_2/3O₃ (PMN) and are typical representatives for most of all ferroelectrics materials with relaxor characteristic. It posses high dielectric permittivity which nearly ~ 20,000[ with a broad dielectric permittivity characteristic, known as relaxor ferroelectric below room temperature. Some of the researcher might think that the transition from relaxor ferroelectric to paraelectric is similar to the characteristic as observed from ferroelectric to paraelectric, but it is not necessary. The puzzling is how do we categorise them. How is the domain structure look like typically in ceramic materials.

Abstract: In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.

Abstract: Poly-Silicon nanowire (Poly-Si-NW) simulations are very important field of nanotechnology and nanostructures; in this paper presented review in general nanowire and it applications such as thermoelectric device (TED) has potential applications in areas such as chip level cooling/ energy harvesting and many more applications in this field .COMSOL multiphysics is one of programmers using for nanotechnology and nanowires simulation, hence in this review paper, COMSOL simulation with different types of materials using for nanowire and other structures. Also In this work, we explore the effect of the electrical contact resistance on the performance of a TED. COMSOL simulations are performed on Poly-SiNW to investigate such effects on its cooling performance. Intrinsically, Poly-SiNW individually without the unwanted parasitic effect has excellent cooling power density. However, the cooling effect is undermined with the contribution of the electrical contact resistance.

Abstract: The ability of pomelo peel (PP) as natural adsorbent to remove Cu (II) ions from aqueous solution was investigated. The influence of solution pH, contact time and temperature were evaluated. Cu (II) removal increased as the pH of the solution increased and the maximum value reached at pH 6. The adsorption was relatively fast (30 min). Adsorption kinetics followed the pseudosecondorder model. At low temperature the adsorption was not affected but at high temperature it was reduced. PP is considered as low cost material that shows potential to be applied in wastewater technology for remediation of heavy metal contamination.