Amirul Abd Rashid

Study on Hydrothermal Process Variables Correlation to WO3 Nanostructure through Design of Experiments (DOE) Approach

There are few known parameters which govern tungsten trioxide (WO3) hydrothermal synthesis process which includes material source concentration, synthesis temperature, duration, pH value and additive level. Using design of experiments (DOE) approach, a systematic experimental procedure was conducted to investigate the effect of each parameter to the final morphology of the synthesized nanostructure. Despite the response obtained from this study is in qulitative form, the analysis still can be done to identify the combination of variables that most likely can produce either 1-D, 2-D or 3-D nanostructure. This insight is essential before further optimization of the process can be done in order to predict the behavior of the WO3 hydrothermal synthesis process.

PH Tester Gauge Repeatability and Reproducibility Study for WO3 Nanostructure Hydrothermal Growth Process

PH value is one of the important variables for tungsten trioxide (WO3) nanostructure hydrothermal synthesis process. The morphology of the synthesized nanostructure can be properly controlled by measuring and controlling the pH value of the solution used in this facile synthesis route. Therefore, it is very crucial to ensure the gauge used for pH measurement is reliable in order to achieve the expected result. In this study, gauge repeatability and reproducibility (GR&R) method was used to assess the repeatability and reproducibility of the pH tester. Based on ANOVA method, the design of experimental metrics as well as the result of the experiment was analyzed using Minitab software. It was found that the initial GR&R value for the tester was at 17.55 % which considered as acceptable. To further improve the GR&R level, a new pH measuring procedure was introduced. With the new procedure, the GR&R value was able to be reduced to 2.05%, which means the tester is statistically very ideal to measure the pH of the solution prepared for WO3 hydrothermal synthesis process.

Low Dense CNT for Ultra-Sensitive Chemoresistive Gas Sensor Development

This work was aimed to develop chemoresistive base sensor on silicon platform. Carbon nanotube (CNT) with low density was grown on passive interdigitated (IDE) based sensor which later can be functionalized with other material for the selectivity of the targeted goals. Low dense CNT will provide a bigger area of the functionalities element adhered to the wall hence increase the sensitivity of the sensor. In situ CNT growth was achieved using a PECVD machine with the time parameter was varied targeting for low dense CNT grow in-between the IDE fingers. SEM analysis reveals that low dense CNT was evidence for growth time as short as 30 s and as the time increase, the density was also increasing. Resistive probing of the grown CNT samples shows a drop in resistance compared to non-grown CNT which confirmed that the CNT successfully conducting the electron. CO2 gas testing shows that the low dense sensor shows better detection performance compared to high dense sensor. However, further study needs to be conducted to measure the level of amorphous carbon which determine the purity of the such CNT nanostructure.

Selective ZnO Nanorods Hydrothermal Growth through Resist Patterning Method

Resist patterning method has been used to enable selective ZnO nanorods grown via facile hydrothermal process. The growth region of the ZnO nanorods was controlled by pre-coating the seed layer on the Silicon base substrate. Using the plasma process, the seed layer which is not coated with a resist layer will be etched out. Therefore, when the samples completely undergone the hydrothermal process, there will be no nanorods grow in that specific area. The grown ZnO nanorods was in well array with flat hexagonal tip and wurtzite crystal structure. This technique is can be applied for application which require integration of nanostructure in specific critical areas such as an interdigitated electrodes (IDE) for various gas sensor applications.

Solder Short Reject Reduction in Soft Solder Die Attach (SSD) Process Using Mechanical Solder Shield Design

This paper presents a development of mechanical solder shield, which was integrated to the Soft Solder Dispenser (SSD) die attach machine. The innovation of the mechanical shield has proven its ability to prevent the molten solder overflows to the lead area of the device. As a result, it reduced number of solder short defects. The manufacturing assembly yield is maintained at the highest level; ensuring fitness for function and production cost of the product remain competitive.

Performance and Emissions of Jatropha-Palm Blended Biodiesel

This paper deals with performances and emissions of Jatropha-Palm blended biodiesel as fuel for 4-stroke single vertical cylinder diesel engine. Five fuel samples were tested; i) Diesel fuel supplied by Petronas (PDF); ii) 5% of blended Jatropha-Palm biodiesel and 95% Diesel fuel (B5JPB); iii) 10% of blended Jatropha-Palm biodiesel and 90% Diesel fuel (B10JPB); iv) 15% of blended Jatropha-Palm biodiesel and 85% Diesel fuel (B15JPB); and v) 20% of blended Jatropha-Palm biodiesel and 80% Diesel fuel (B20JPB). Engine performances (specific fuel consumption, brake thermal efficiency) and emissions (exhaust gas temperature and Nox emission) were analyzed and have been discussed in this study. All tests were carried out at varied load conditions which were 0.13, 0.15, 0.17, 0.19 and 0.21 kW. The results revealed that B10JPB blended showed better engine performances compared to its other blends and comparable performances compared to PDF. Comparable Nox emitted of all Jatropha-Palm fuel blended biodiesel fuel sample has been demonstrated to those PDF.

Mechanical properties and microstructure analysis of 0.5% Niobium alloyed ductile iron under austempered process in salt bath treatment

The purpose of this work was to compare the mechanical and physical properties for 0.5% Niobium alloyed ductile iron (0.5% Nb-DI) with commercial ductile iron (DI) before and after austempering process. The materials for this investigation were produced by conventional CO2 sand casting process and machined to TS EN 10001 standards for tensile test and ASTM E23 for Charpy impact test. Hardness test, density test and polarization test were also done to the samples. Microstructure observations were made after 2% Nital chemical etched and the fractured surfaces obtained through broken samples of tensile and impact test were evaluated through Scanning Electron Microscopy (SEM). The samples were austenitized at 900°C for 1 hour followed by austempered in a salt bath at 350°C for 3 different holding times which were 1 hour, 2 hours and 3 hours subsequently. The samples were then let cooled to room temperature. All testing were done before and after heat treatment process. The newly developed Nb alloyed DI possessed significant improvement in term of mechanical properties and corrosion behavior in comparison with pure ductile iron. Enhanced properties of the materials make them suitable for various technical and industrial applications.