Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral - Tesis

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Fabrication Of Porous Ceramic Foam As Catalyst Support For Hydrotalcite In The Production Of Fatty Acid Methyl Esters (Fame)
(2014-12)
Sharif, Sharmiwati Mohammed
The increasing demand for liquid petrol fuels, as well as their higher price, biodiesel has been gaining worldwide popularity as an alternative energy source. The classic ways of producing biodiesel have certain difficulties and disadvantages such as that determined researchers for finding alternative technologies for its production. Thus, upgraded technology of biodiesel production has been proposed. The tubular porcelain catalyst as the catalyst support and hydrotalcite as the heterogeneous catalyst were prepared. Analyses have been done including the methods of preparation of the tubular ceramic support with the replication polymeric sponge method, characterization of mechanical and microstructure properties of tubular ceramic support and the application on the transesterification of commercial palm cooking oil to biodiesel. T
Joining Of Alumina-Based Composite To 6061 Aluminum Alloy By Friction Welding
(2014-06)
Safarzadeh, Marjan
The present research is aimed at evaluating the feasibility of using the friction welding of mullite and Alumina-Mullite composite with 6061 Alalloy, and subsequently determining their microstructural and mechanical properties. During the process, friction force (1000 bar) and friction time (30 Sec) were held constant while the rotational speed was varied. Ceramic rods aluminium rods were machined down to get the require dimension and then polished. Sintering behaviour of ceramic samples were investigated. It was concluded that the mullite rods didn't join to 6061 Al-alloy due to the low fracture toughness of the mullite. Thus, fracture toughness was improved through the composite of Alumina-Mullite. Welding process was carried out under two different rotational speeds (1250 and 1800rpm) and the effect of increasing rotational speed on microstructure, microhardness and mechanical properties of Alumina-Mullite composite/6061 Al-alloy joined was evaluated. It was observed that a good microstructure with higher mechanical properties (microhardness and bending strength) were achieved from the joining of Alumina-Mullite composite with 6061 Al-alloy at higher rotational speed (1800 rpm). The mechanisms of failure at the fracture surfaces revealed different feature at different speed. At the higher speed dimple and ductile formed which implies the plastic deformation.
Synthesis And Characterization Of Zno, V2O5 And Mno2 Nanostructures Photocatalysts On Polyetylene Terephthalate (Pet) Fiber For Degradation Of Rhb Dye
(2014-04)
Chan, Yim Leng
Increasing pollution into the water system particularly from textile industries and agriculture has become a source of health concern across the globe. Advanced oxidation process is a rapid developing research field for the application in degradation of organic the semiconductor's surface in the presence of UV or visible light irradiation. In order to utilize sunlight effectively for organic pollutants removal, the photocatalytic activities of wide bandgap semiconductor (ZnO. Eg =3.37 eV) and narrow bandgap semiconductors (MnO2. Eg = 1.00 to I.<30 eV and polymorphs of MnO2 nanoparticles were synthesized using hydrothermal method by adjusting the ratio of KM11O4 and MnSO4. The photodegradation of RhB solution by these semiconductor nanoparticles followed first order kinetic. Under UV irradiation. ZnO has good photodegradation efficiency (0.034 min'1). On the other hand. V2O.s nanorods and p- MnO2 nanoparticles degraded RhB dye under visible light with rate constant of 0.01 5 min'1 and 0.022 min'1 respectively. A relined photodegradation model of RhB solution by these semiconductor photocatalysts is proposed. Two processes, i.e. N-deethylation and cycloreversion happen simultaneously during the photodegradation of RhB solution.
Effect Of Additives, Polyvinyl Alcohol And Silica On Properties Of Sago Starch Plastic Films
(2022-10)
Zaaba, Nor Fasihah
In this research, studies on properties of sago starch plastic films with the additional of various additives, polyvinyl alcohol and silica were carried out. The additives used in this research were glycerol (GLY), polyethylene glycol (PEG) and glutaraldehyde (GLU). Glycerol and polyethylene glycol were used as plasticizer to brittleness, caused by high intermolecular forces. While, glutaraldehyde was used as crosslinking agent to increase the tensile strength of films by increasing the cross linking structure. Sago starch plastic films were prepared through blending process followed by casting method. From the results obtained, film with the addition of 2 wt% glutaraldehyde shows the highest tensile strength. Besides that, results showed that the glycerol-plasticized films exhibited higher elongation at break and tensile strength than that of polyethylene glycolplasticized films, which mainly due to the better plasticizing effect of glycerol. Degradability test revealed that the weight loss of unplasticized sago starch plastic films was lower than of glycerol- and polyethylene glycol-plasticized sago starch plastic films. The effectiveness of polyvinyl alcohol (PVA) on sago starch plastic films was studied and compared in the presence of glycerol as plasticizing agent and glutaraldehyde as crosslinking agent.
Fabrication And Characterization Of Embedded Gold Nanoparticles In Metal Contacts For Silicon And Silicon Carbide-Based Devices
(2014-06)
Gorji, Mohammad Saleh
Embedding metal nanoparticles (NPs) into metal contacts, at the interface with semiconductor, is an alternative method for modification of Schottky barrier height (SBH) in electrical contacts and offers a tremendous simplification and adaptation in processing steps. Schottky barrier diodes with aluminum (Al) contacts embedded with gold (Au) NPs on n- and p-type silicon (Si) and silicon carbide (4H-SiC) substrates were fabricated and their physical and electrical characteristics were investigated. Based on the studies on Si surface contact angle measurement and the negative zeta-potential values of seeded growth 20 nm Au NPs, an alternative approach was proposed to deposit Au NPs on linker-free n- and p-Si substrates using spin-coating technique. Density of NPs (determined by scanning electron microscope) on n-Si was substantially higher than p-Si which was due to the differences in surface properties of n- and p-Si. Current-voltage analysis of diodes revealed an increase in current density in both bias directions due to NPs local electric field enhancement effect and SBH lowering (0.1 1 eV for n- and 0.05 eV for p-Si). The electrical results were then correlated to the structural properties of Al/Si (determined by transmission electron microscope). Higher density of 5 and 10 nm Au NPs were deposited on SiC surface by using acidification technique with diluted HF. Al/4H-SiC diodes showed great improvement in SBH lowering (0.09 eV for n- and 0.24 eV for p-4H-SiC) and hence forward bias current density elevation while maintaining the rectification properties in reverse bias.

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