Search

Alumina is one of bio-ceramics that have been used as bone replacement material in modern health care industries due to its good mechanical properties. Unfortunately, their potential as bone implant depends upon its strength and compatibility with the biological environment. Since palm stearin possesses low molecular weight, which can prevent residual stress and distortion with abundantly available in Malaysia (low cost). Furthermore, bone implant using palm stearin as a binder has never been studied before. Thus, a study has been carried out to investigate the effect of different contents of Palm Stearin (35 vol%, 36 vol%, 37vol % and 38 vol%) with different sintering temperatures (1300°C, 1350°C, 1400°C, and 1450°C) using a slip casting process to produce porous alumina like the human bone. The samples then were characterized in terms of physical and mechanical properties. The water impregnation test was used to determine the percentage of porosity of the sample whilst Scanning Electron Micrograph (SEM) to determine its pore structure. Three-point bend test and hardness test were used to determine its flexural strength and hardness respectively. It was found that by using 36 % volume of palm stearin and 64% volume alumina which sintered at 1400°C has porosity of 41.63% with a pore size measured 112μm in diameter. The flexural strength and hardness valued at 5.366 MPa.

Aluminium foam is a material that structured by porous medium with certain characteristics such as good energy absorption, high heat conductivity and good heat transfer. These characteristics that aluminium metal foam provides, can be used in wide range of applications such as on heat exchanger, automotive and etc. The aim of this study is to evaluate the heat conductivity and permeability of the aluminium foam. The porosity of aluminium foam produced by NaCl replication are ranging from 60% to 75%. Besides, simulation by CFD software were carried out to compare with the effect of pore structure on heat conductivity and to determine the heat flux. At the end of the study, the heat conductivity value and permeability of experimental and analysis were identified. The value of heat conductivity k of aluminium foam is better compared to solid aluminium when the temperature increased. The permeability of the aluminium foam is dependent on the porosity of the aluminium foam. Higher porosity resulting to a higher rate of permeability.

This study presents the effects of sintering temperature and binder content of polyethylene glycol (PEG) on wear properties of compacted alumina using pin on disc wear test under dry sliding condition. Wear rate was measured at 20N load and sliding speed of 200rpm at 0.28 m/s sliding velocity. The wear test sample was tested at 3 different sintering temperatures (1000°C, 1100°C, and 1200°C) to produce different microstructures. The results show that a dry pressed alumina ceramic with 5 wt. % of PEG content and sintering temperature at 1200°C recorded the lowest wear rate and volume lost compared to other samples. SEM was carried out to investigate the microstructure how it affects the wear property. It was found that at high sintering temperature of 1200° C the particle formation was strengthen to each other hence promote highest wear resistance.

As the global population increased, the production of vehicles also has increased. It is estimated that the population of vehicles in the world has exceeded 1.32 billion units at the end of 2016. The increased vehicle production brings a lot of negative impact to the environment such as noise pollution and the increase of end-of-life vehicles (ELVs). This study aims on the potential of recycled polypropylene that has been used in ELVs. The recycled materials are obtained from vehicles dismantling center at DRB-HICOM Environmental Services Sdn Bhd. The materials were then cleaned and crushed into the pellet before undergoing rheological test at the heat treatment laboratory, Faculty of Mechanical Engineering in Uitm Shah Alam. The purpose of rheological test is to study the melt flow behavior of recycled polypropylene in order to obtain the optimum temperature to be applied in plastic injection molding process. The graph of shear viscosity vs. shear rate represents the behavior of both materials at 190°C, 200°C and 210°C. Then materials are produced as a new product. The process of plastic injection molding is carried out at Sheikh Brothers Industries Sdn Bhd in Pelabuhan Klang.

This project is to study the effect of welding preheat on metallurgical analysis and microstructural development. Variables such as current, speed of welding and size of specimen were fixed. In the present work, a mild steel plate with thickness of 100 mm and width size of 20 mm was used. SMAW (Shielded Metal Arc Welding) technique was chosen as it is the easiest way to perform and widely used in oil & gas and marine industries. Three different preheat temperatures were performed during the study; ambient temperature (no preheat), between 60 °C to 70°C and greater than 200 °C. The study emphasizes on the minimum preheat temperature that produce good quality welding by taking into account some of metallurgical aspects; microstructure and macrostructure development, hardness distribution at important areas in weld (Heat Affected Zone, parent metal and weld area) through thickness. From this study, code American Welding Society (AWS) D1.1 was used as a reference and it stated that for plate that has 100 mm thickness the preheat temperature should be in the range of 60 °C and 70°C. The result of microstructure and macrostructure showed that the depth of penetration was not vary too much. Hardness measurement, macro and microstructure observation were performed in order to obtain a good correlation exist between these parameters studied.

Silver nanoparticles (AgNPs) have found significant application in industry especially in medical and catalysis field. Considerable attention has been made to synthesis AgNPSs via various routes. However, in recent years, focus have been shifted to synthesis AgNPs using more environmentally friendly route. Attempts to synthesis AgNPs by using plant extracts as potential complex reducing agent have found significant interest to date. Hence, this work will explore the feasibility to synthesis AgNPs by using locally available Graptophyllum pictum leaves (puding hitam). The extracts were evaluated on the their total phenolic content to shed potential insights on the mechanism prior AgNPs synthesis. The feasibility of the AgNPs were evaluated by using UV-Vis and Transmission electron microscopy (TEM). In conclusion, Graptophyllum pictum leaves (puding hitam) could be a viable alternative for the environmentally friendly synthesis of AgNPs.

Selective Laser Melting (SLM) has been one of the preferred Additive Manufacturing process to fabricate parts due to its merits in terms of design freedom, lower material waste and faster production when compare to the conventional manufacturing processes. However, due to the thermal gradient experienced during the process, the parts are exposed to the residual stress that leads to parts distortion. This work presents the effect of heat treatments on the micro-hardness of 316L stainless steel parts. In current study, SLM has been employed to fabricate 316L stainless steel compacts. Different heat treatments of 650°C, 950°C, and 1100°C for 2 hours were applied on the compacts. Hardness test were performed on the as-built and heat-treated compacts. The relationship between the microstructures and micro-hardness were discussed in this paper. The results revealed that the micro-hardness of the as-built compacts is between 209.0 and 212.2 HV, which is much higher than the heattreated compacts.

Polycaprolactone/Hydroxyapatite (PCL/HA) composite is an excellent material for fabricating tissue engineering scaffolds, especially as bone scaffolds. However, polarity differences between the hydrophilic HA and the hydrophobic PCL often leads to poor dispersion during the blending process. This is due to the tendency of the HA particles to agglomerate, and the difficulty to efficiently mix the polymer melt at high loading. The objective of this study is to introduce ultrasound waves during the conventional melt blending to overcome the problem. PCL and needle-shaped hydroxyapatite (HAN) were blended using an ultrasonically assisted extruder. The morphology of the PCL/HAN blend was investigated using field emission scanning electron microscopy (FESEM). This study found that the presence of ultrasound waves during melt blending was helpful in breaking up the HAN agglomerates. Thus, better dispersion of HAN was obtained, although some small agglomerates of HAN were still observed.

A rheological behaviour of the powder-binder mixture is one of essential analysis upon to success of Metal Injection Moulding (MIM) process. The purpose of this experimental work is to investigate the rheological behavior of feedstock containing mixtures of elemental Ni and Ti powders mixed with composite binder of palm stearin (PS) and polyethylene (PE) binder system. An equiatomic Ni-Ti (50-50) ratio was used in the present work for all formulations owing to excellent shape memory behaviour. The experimental rheological result indicated that all the feedstocks exhibited pseudo plastic flow behaviour; viscosity decreasing with temperature and shear rate. Increasing the powder loading resulted in higher viscosity, particularly at the low-range of shear rate. Owing to pseudo-plastic flow, it was found that the feedstock prepared exhibit promising rheological properties, thus resulting successfully injection moulding at an optimum temperature of 130°C.