Machining of fiber reinforcement polymer (FRP) composite without any defect is extremely challenging when using conventional processes. This mainly due to its inherent anisotropic, heterogeneous, thermal sensitivity, and highly abrasive of nature of fiber reinforcement. Therefore, a kind of non-conventional machining process namely abrasive waterjet machining (AWJM) was endeavoured as it has been reported to be able to machine or cut almost any material included composites. In fact, previous research only provides partially desired parameters on machining these materials and mainly focuses on plain FRP composite. Therefore, this research attempted to evaluate the significant AWJM process parameters comprehensively on the main machinability output on the hybrid FRP composite. 2k factorial design and statistical analysis of variance (ANOVA) were applied to determine the performance of trimming process regarding surface roughness and delamination (entrance and exit). Experimental results revealed that the surface roughness was affected by the stand-off distance, abrasive flow rate, traverse rate rather than hydraulic pressure. Similar findings as to that of surface roughness were also observed for the top and bottom delamination damage.

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Silicon carbide nanotube (SiCNTs) has been proven as a suitable material for wide applications in high power, elevated temperature and harsh environment. For the first time, we reported in this article an effective synthesis of SiCNTs by microwave heating of SiO 2 and MWCNTs in molar ratio of 1:1, 1:3, 1:5 and 1:7. Blend of SiO 2 and MWCNTs in the molar ratio of 1:3 was proven to be the most suitable for the high yield synthesis of β-SiCNTs as confirmed by X-ray diffraction pattern. Only SiCNTs were observed from the blend of MWCNTs and SiO 2 in the molar ratio of 1:3 from field emission scanning electron microscopy imaging. High magnification transmission electron microscopy showed that tubular structure of MWCNT was preserved with the inter-planar spacing of 0.25 nm. Absorption bands of Si-C bond were detected at 803 cm -1 in Fourier transform infrared spectrum. Thermal gravimetric analysis revealed that SiCNTs from ratio of 1:3 showed the lowest weight loss. Thus, our synthetic process indicates high yield conversion of SiO 2 and MWCNTs to SiCNTs was achieved for blend of SiO 2 and MWCNTs in molar ratio of 1:3.

In this paper, the effect of ratio of silicon dioxide and graphite for the synthesis of silicon carbide nanowhiskers by microwaves heating was reported. The mixtures of SiO2 and graphite with different ratio were prepared by ultrasonic mixing using ethanol as medium. The mixtures were dried on hotplate and cold pressed by using hydraulic hand press uniaxially into a pellet die. The mixture in the form of pellet were heated up to 1400 °C at heating rate of 20 °C/min and soaked for 30 minutes. Scanning electron microscopy was used to study the morphology of sample of each different ratio of mixture. It was found that almost complete conversion of graphite and silica to silicon carbide nanowhiskers was observed for sample of mixture SiO2 and graphite in the ratio of 1:3. Result from x-ray diffraction analysis also indicated that single β-SiC phase was present in the diffractogram of silicon carbide nanowhiskers synthesized from mixture SiO2 and graphite in the ratio of 1:3.

Conventional methods for the synthesis of silicon carbide were well studied and these methods included carbothermal reduction, mechanical milling, sol-gel process and others. However, conventional methods have limitations such as high energy consumption, presence of impurities and long reaction times. In this paper, microwave heating was applied for the first time for the synthesis of silicon carbide nanotube owing to the advantages of microwave heating such as shorter reaction time, uniform heat distribution and low cost. Mixture of silicon dioxide and carbon nanotube in the ratio of 1:3 as suggested by previous study were mixed in ultrasonic bath using ethanol as liquid medium for 2 hours and then dried on hot plate to evaporate ethanol. The mixture was then cold pressed into 3mm pellet and placed into an alumina crucible filled with silica sand acts as sand insulator and SiC susceptor. The pellet was heated to 1400°C with heating rate of 30°C/min for 40 minute. X-ray diffraction pattern verified the presence of single β-SiC phase in silicon carbide nanotubes. Meanwhile, scanning electron microscopy revealed that tubular structure of carbon nanotube was retained after microwave irradiation and energy dispersive x-ray spectroscopy shown the silicon carbide nanotube consist of only elemental C and Si and thus indicated that silicon carbide nanotubes were successfully synthesized through microwave irradiation.

Silicon carbide is an attractive material for engineering and industrial applications in harsh conditions. In manufacturing process, conventional heating process is commonly used to synthesis the silicon carbide. In this study, SiC nanowhiskers were synthesized from microwave heating of mixture of graphite and silica in the ratio of 3: 1. The mixture was heated by using laboratory microwaves oven to 1400°C at heating rate of 20 °C/min and temperature was hold for 30 minutes. Photoluminescence spectroscopy and Fourier transform infrared spectroscopy were used to characterize the SiC nanowhiskers. Photoluminescence spectrum of SiC nanowhiskers showed a sharp peak at 420 nm corresponding to band gap of SiC (2.39 ev). FTIR absorption spectra of SiCNWs recorded a band at 805.22 cm-1 corresponding to Si-C bond.

In this study, porous SiO2·RO/stainless steel composite body was prepared through the polyurethane sponge replica method. Porous samples obtained through sintering consist of well dispersed and distributed stainless steel particles within the glass matrix. Such microstructure is desired for the purpose as a soot particulate filters (DPF) utilizing microwave rapid and selective heating characteristic, especially during the cold start phase of an engine. Results of microwave heating ability and diesel soot regeneration tests shows that, the fabricated porous composite material is proven to be reliable for rapidly microwave assisted regeneration. Both the regeneration temperature and O2composition in the supplied gas played an important role in the regeneration process.

Magnesium (Mg) alloy possess a high demand in biomedical applications due to their biocompatibility and biodegradability. However the main limitation for Mg alloy is their fast degradation rates in physiological environment. This paper reports the preparation of porous Mg alloy through powder metallurgy technique by using ammonium bicarbonate (NH4HCO3) as space holder material and hexane as solvent. The corrosion behavior and degradation rate of porous Mg alloy was measured after 24h, 96h and 168h respectively of immersion in simulated body fluid (SBF) with compact Mg alloy as control. The results reported that degradation rate increased with increasing immersion period, yet the compact Mg alloy shows better degradation rate than porous Mg alloy. Moreover, the pH of SBF changed proportional to immersion period and stabilized after 96h of immersion.