Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral - Tesis
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- PublicationSynthesis And Characterization Of Fe-Doped Zinc Oxide Rods(2014-12)Abd Aziz, Siti Nor Qurratu AiniChemical vapor deposition (cvd) technique is the most common vapor route technique uses by researchers to synthesize zno nanostructures. However, the current in-situ doping approaches using cvd do not give many flexibilities for the researchers to produce doped zno nanostructures. As the dopant solution is kept outside the furnace, the aerosol assisted - chemical vapor depostion (aa-cvd) is a potential in-situ doping technique because it offers many advantages such as flexibility of controlling the doping concentration, doping duration, type of dopant precursor and possibility of mass production of doped nanostructures. This project started by setting up a cvd system to synthesize undoped zno rods without using foreign catalyst. The study indicated that the optimum synthesis condition for synthesizing undoped zno rods was using 0.3 g zn powder, 30 min synthesis duration, and 5 cm distance of si substrates from zn powder at 650 °c. The average length, diameter, aspect ratio and areal density of undoped zno rods are 2.99 ±0.13 pm, 0.54 ± 0.05 pm, and 5.6 ± 0.3, 2.9 ± 0.9 rods/pm , respectively. Subsequently, ex-situ fe-doping was performed via spray pyrolysis on the pre-grown zno rods. The physical properties of fe-doped zno rods prepared by ex-situ doping would be used to compare with the fe-doped zno rods prepared by in-situ doping in the subsequent phase.
- PublicationEffect of nickel catalyst on the formation of TIH2 experiemntal and numerical(2018-08-04)Aws Sadoon Mohammed Al JanabiThe formation of titanium hydride (TiH2) was studied in the presence of Nickel (Ni) and ammonia chloride (NH4CI) as a catalyst. Calcium hydride (CaH2) and titanium tetrachloride (TiCl4) were used as a reactant in a hydrogen (H2(g)) atmosphere at 1 atm. Three parameters were investigated, temperature (A), Ni catalyst ratio to CaH2 weight (B), and reaction time (C). Temperature parameter was investigated at, 300 °C, 400 °C, and 500 °C. The Ni catalyst percentage was varied between 10%, 30%, and 50% with respect to CaH2 weight. Reaction time was studied at 3, 4, and 5 hours. Design of experiment software was used to design the experiments while HSC software were used to determine thermodynamic calculations for predicting equilibrium composition. A shrinking core model (SCM) was used to predict the degree of dehydriding, XH (%). The synthesised product were characterised by XRD, SEM/EDS, CHNS, and weight gain calculations The phases detected via XRD were TiOCI, Ca(OH)2, CaCl2*(H2O)x, TiO2 (anatase & rutile), NiTiO3, and CaCIOH. The desired phase, TiH2 was assumed to be formed but reacted with Ni and moisture to form NiTiO3. The sample with the parameters of 500 °C, 50% catalyst, 3 hours of reaction time had the highest weight gain, Xw (%). In contrast, the sample with parameters of 300 °C, 50% catalyst, 3 hours of reaction time had lowest Xw (%). CHNS analysis had detected 2.1 wt.% of hydrogen in the highest Xw (%) sample. SEM/EDS showed the presence of TiO2, Ni, and CaCl2. Design expert software showed temperature was the most effective parameter for both of the responses, Xw (%) and XH (%).
- PublicationThermal performance of computer micro-processor using microchannel heat sink with nanofluids(2016-12)Tony, Tan Hin JooIn the rapid development of electronic technology, the demand of high capacity in computer performance is increasing every year. The higher the performance of computer the higher the heat will be released from the computer processor. Without proper management of the heat release, the generated high heat will cause computer performance deteriorate due to high temperature and may cause damage consequently. Furthermore, the continuous miniaturization process of electronic component has contributed impact to the size of cooling system which is incorporated with the electronic component. As commonly found in the current technology of cooling system, the conventional size of cooling system is used, and various medium are applied through the cooling system for heat removal purpose. The heat removal capacity of conventional cooling system is limited which is not able to dispel the high heat that generated from high performance computer processor. Furthermore, the larger size of the conventional cooling system can not be fitted into the smaller size of electronic components of the processor. As a result, a proper approach of managing the high heat issue and proper physical size of cooling system is required, in which microchannel heat sink is introduced. In the research work, various operating conditions (pressure drop [range: 20Pa – 38Pa], temperature [range: 342K – 354K] and Reynolds Number [range: 70 – 1150]), physical dimensions and channel configurations (rectangular, triangular and trapezoidal) are considered and analysed in order to investigate their impact on the microchannel heat sink performance in terms of pressure drop, pumping power, thermal resistance, and heat transfer coefficient. Besides this, various cooling working medium has been used such as distilled water and nanofluid (Distilled Water H2O + Alumina Al2O3 and Distilled Water H2O + Silica SiO2) with various concentrations of nanoparticles (1%, 2% and 3% concentration). Simulation work by applying Finite Volume Method (FVM) in FLUENT software has been carried out to simulate the engineering results for the performance of microchannel heat sink. It is found that the physical dimension and geometrical channel configuration have obvious impact on the microchannel heat sink performance in which the case of rectangular channel that provides the highest heat transfer performance. Besides this, the research work also shows that the effect of different types and concentrations (1%, 2% and 3% concentrations) of nanoparticles within cooling medium plays important role onto the microchannel heat sink performance. The increment of cooling performance by 40% can be achieved by adding nanoparticles into cooling medium as compared with pure distilled water. Furthermore, the increment of cooling rate also can be achieved by the increment of nanoparticles concentration. In the research work, nanofluid Alumina provides the higher cooling rate as compare with pure distilled water and nanofluid Silica due to the effect of high thermal conductivity. However, the small amount of nanoparticles concentration would not affect hydrodynamic performance of microchannel heat sink. As a result, the physical dimension, channel geometrical configurations, existence of nanoparticles within cooling medium are vital factors that able to affect and incur obvious impact on the performances of microchannel heat sink hydrodynamically and thermally. To ensure the result of the simulation work above is reliable, the experimental works have been carried out for validation and comparison.
- PublicationFabrication Of Porous Ceramic Foam As Catalyst Support For Hydrotalcite In The Production Of Fatty Acid Methyl Esters (Fame)(2014-12)Sharif, Sharmiwati MohammedThe 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
- PublicationJoining Of Alumina-Based Composite To 6061 Aluminum Alloy By Friction Welding(2014-06)Safarzadeh, MarjanThe 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.