Theses & Dissertations

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https://hdl.handle.net/20.500.14170/1590

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Now showing 1 - 5 of 133
  • Publication
    Study on bio-oil derived from catalytic pyrolysis of torrefied EFB with Cobalt alumina
    ( 2022)
    Amierah Rasyeedah
    Fast pyrolysis is emerging as a promising route for the production of liquid fuels from biomass. However, pyrolysis derived bio-oil needs to be upgraded prior to its utilization as a fuel and hydrodeoxygenation (HDO) is an important catalytic step in it. Furfural has been considered as one of the most promising platform molecules directly derived from biomass. The hydrogenation of furfural is one of the most versatile reactions to upgrade furanic components to biofuels. For instance, it can lead to plenty of downstream products, such as tetrahydrofurfuryl alcohol, 2-methyltetrahydro furan, lactones, levulinates, cyclopentanone, or diols. Design of suitable catalysts with high activity and selectivity for the HDO process would require detailed understanding of the underlying catalytic reaction mechanism. Since cobalt alumina-based catalysts have been proposed to be the most effective HDO catalysts, the complete reaction network for HDO of furfural, a representative of furanic compounds present in bio-oil, is elucidated in this study on cobalt alumina surface, using Density Functional Theory calculations. Reaction pathways for the formation of Furfuryl alcohol (FA), Tetrahydrofurfuryl alcohol (THFA), Methyltetrahydrofuran(MTHF), Methylfuran (MF), Cyclopentanol, 1,2 and 1,5 pentane diols, Furan and Pentanes are established. Furan ring opening is facile on cobalt alumina surfaces and our calculations predict pentane formation to be thermodynamically and kinetically favoured in the vapour phase hydrodeoxygenation of furfural on cobalt alumina surfaces.
  • Publication
    Optimization of processing parameters for physical, mechanical and chemical properties of Khaya senegalensis fuel pellets
    ( 2024)
    Ras Izzati Ismail
    Flourishing even in less-than-ideal conditions, the rapid growth of the Khaya senegalensis (khaya) tree requires regular pruning, presenting a challenge in waste management. To address this, the study proposes repurposing the pruning waste to manufacture energy pellets, offering an eco-friendly solution to waste removal. Pellets offer improved energy density, bulk density, moisture content, and homogeneity, thereby reducing storage, handling, and transportation costs. Notably, there is a lack of scientific gap on using Khaya senegalensis wood for fuel pellet production. To produce high-quality solid fuel, it is essential to comprehend the properties of wood fuel. Due to this necessity, the current study examines the effects of pelletization temperature, pressure, particle size, feedstock moisture content and binder percentages on fuel pellet properties, particularly on their physical, mechanical and combustion characteristics. In this study, the methodology involved determining the fuel characteristics of Khaya senegalensis wood biomass, including bulk density and calorific value, followed by the fabrication of fuel pellets from varying feedstock parameters. The effects of these parameters on pellet properties were analyzed through a parametric study, and response surface methodology was employed to optimize the processing conditions for enhanced pellet quality. The study achieves its first objective by comprehensively assessing the fuel characteristics of Khaya senegalensis wood, with bulk density measured at 258 kg/m³, moisture content (26.06 %), ash content (5.38 %), volatile matter (83.07 %), fixed carbon (15.46 %), and calorific values (16.11 MJ/kg). The second objective involves a parametric study, investigating the effects of pelletizing parameters on mechanical strength and combustion characteristics. The study successfully establishes relationships and optimized conditions for various parameters, presenting statistically significant findings in response analysis. The third objective employs response surface methodology to optimize pelletizing variables for ideal mechanical and combustion characteristics, resulting in well-validated models and predicted optimized values. Design Expert 13 revealed that khaya pellets performed optimally with factor settings of pelletization temperature at 110 °C, pressure at 5 tonnes, and a binder percentage of 9 %. The optimized values for various responses include axial compressive strength at 55.66 MPa, diametral compressive strength at 9.604 MPa, moisture content at 6.93 %, volatile matter at 87.83 %, ash content at 6.54 %, fixed carbon at 5.31 %, calorific value at 19.08 MJ/kg, durability at 99.93 %, and unit density at 1309.37 kg/m³. In conclusion, all the objectives have been successfully achieved, and the research provides valuable insights into repurposing khaya wood waste for sustainable energy pellet production. Understanding wood biomass, solid fuel qualities, and pelletization parameters for this crop could streamline the production of premium-quality pellets from khaya wood, addressing global energy demands efficiently.
  • Publication
    Synthesis of graphite to graphene by modified electrochemical exfoliation method towards enhanced thermal interface material for heat sink application
    ( 2020)
    Mazlan Mohamed
    Today, heat sink power source has increased significantly for many applications. The study of heat transfer in heat sink is important to ensure that the life expectancy, reliability and performance of the heat sink are higher. The main objective of this research is to reduce the temperature of the heat sink junction by using a thermal interface material, also known as a heating pad. The material used in the heat pad must have high thermal conductivity and heat resistance. Therefore, graphene is used as the main filler material in this research to replace some of the existing materials. The composition of graphene is studied in-depth to determine the effect of thermal conductivity to obtain optimum thermal conductivity. The synthesis process is carried out using the modified electrochemical exfoliation method because it is simple and does not cost much compared to the other methods. Once the graphene production is done, it becomes a thermal interface material. Thermal interface material made of graphene will be compared to existing thermal interface material in terms of thermal conductivity. In this study, the effect of graphene composition greatly influenced the thermal conductivity value, the higher the value of the graphene composition used, the higher the thermal conductivity value. Then, the simulation was performed using Ansys-Fleunt software to obtain the temperature value of the heat sink using the same parameters as the actual conditions. From the results, it is shown that the heat sink temperature using the thermal interface material made from graphene successfully reduced the temperature by 20 to 40 %. The increase in power supplied to the heat sink as well as the chip caused the temperature to rise to 95.6 ºC at 10 Watt but using a thermal interface material made of graphene reduced the temperature to 62.4 ºC. This high-temperature reduction can prevent electronic components, especially heat sinks from becoming very hot and damaged. In addition, the thermal interface material made of graphene has also been shown to have the highest thermal conductivity compared to other thermal interface materials. The 20 to 60 % increase in thermal conductivity makes it the best thermal interface material to be used in reducing temperature to heat sinks. Material which is studied from 10 wt. % up to 100 wt. %. The importance of this study is to help electronic designers decide on the optimum composition that can be used while at the same time, maximizing the reliability and durability of the heat sink.
  • Publication
    Influence of slotted inclination angle on velocity characteristics in fluidization systems via computational fluid dynamics analysis
    ( 2021)
    Ku Mohammad Yazid Ku Ibrahim
    Fluidization is the process in which solid particles are suspended in a fluid-like state and widely used in power generation, chemical process, mineral processing industries, drying process and etc. These studies are carried out due to the constraints on conventional fluidization system which can inferred to; (i) Several type of distributor designs, which can influence the bubble size and lowers the fluidization performance, (ii) The conventional fluidization systems does not fluidize at one specific value thus directly affecting the bed behavior, and (iii) The pressure drop in conventional fluidization is not constant with increasing air velocity; affecting bed weight or bed moisture content. Therefore, the current study aims to; (i) Ability to assess the operational range of several types of distributor that focus on slotted inclination angle and slotted number of perforated plate distributor, (ii) Ability to verify the velocity component on airflow distribution of a current perforated plate distributor design, and (iii) Ability to evaluate the optimum geometry of perforated plate distributor via optimisation method that focuses on low pressure drop, uniform velocity and high tangential velocity. In order to achieve the goal outlined, several methods have been proposed in these studies. Firstly, the numerical simulation of Computational Fluid Dynamics (CFD) was used to investigate the parameters that can influence the perforated plate distributor with varying slot numbers (10, 12 and 14) and at various slotted inclination angles (15°, 45° and 90°). Secondly, the CFD is used to investigate the velocity characteristics of each velocity component such as velocity magnitude, tangential velocity, axial velocity and radial velocity as well as the pressure drop effected by slotted distributor configuration. And thirdly, the extracted data was evaluated by using statistical analysis on mean values, standard deviation, and also using an optimisation method like Full Factorial Design (FFD). It has been observed that the most significant findings in this study which represent the optimum design of a perforated plate distributor in a fluidization system were 45° angled slot inclination and 10 slots number respectively. This optimum design has formed a velocity uniformity with a higher tangential velocity of 24.39 m/s with a low standard deviation of 3.7% and a lower pressure drop of 2817.24 Pa, respectively. Moreover, extended analysis via optimisation method using ANOVA has shown that slotted inclination angle has significant parameter on the values of mean tangential velocity and pressure drop. Based on the ANOVA results, pressure drop is the most significant contributing parameter in lessening energy consumption on the fluidization systems.
  • Publication
    Industry 4WRD readiness assessment for Amlex technology: Industry 4.0 strategy dimension improvement via a fishbone analysis
    ( 2021)
    Azhar Md. Nayan
    Industry4WRD Readiness Assessment model introduced by the Ministry of International Trade and Industry (MITI) of Malaysia is among one of the Industry 4.0 readiness assessment and maturity models that can assist the manufacturing companies in identifying the performance gaps and improvement plans towards the Industry 4.0 transformation. MITI's Industry4WRD Readiness Assessment model is also in line with other global implementation initiatives and can be one of the practical worldwide guidelines, references, and standards for the Industry 4.0 transformation. Since early 2015, various Industry 4.0 readiness assessment and maturity models were introduced, and the Industry4WRD Readiness Assessment model is still a new model released in 2018 by MITI. This thesis discussed the methodology and processes of applying the Industry4WRD Readiness Assessment model to assist the manufacturing companies in identifying the current gaps and areas for improvement plans towards Industry 4.0 concepts. In this thesis, one manufacturing small-medium enterprise (SME) was selected to implement the methodology and processes to assess the Industry 4.0 dimensions as the primary focus during a self-assessment and the actual Readiness Assessment. The Industry4WRD Readiness Assessment designed rubrics with a description of criteria to facilitate the processes and methods are demonstrated with the before and after results' computation, and the Industry 4.0 readiness assessment profile has been concluded. This thesis has developed the Industry 4.0 Strategy dimension improvement plan by adopting the Fishbone diagram root cause analysis (RCA) method to address the problem statement faced by Amlex Technology. The final results have shown it improved from score one (1) to two (2) out of four; the maximum score for the Industry 4.0 strategy dimension and the overall People’s C-Value increased from 1.40 to 2.60. The thesis also revealed that the implemented solutions for the Industry 4.0 dimension had improved the overall Industry 4.0 Readiness Assessment profile from 27% to 46%, with improvement also seen on other dimensions for Process and Technology shift factor. It shows that once SME has established the Industry 4.0 strategy, the transformation for Process and Technology can easily be implemented. The other outcome is the SME also can strategizeon all aspects of the People, Process, and Technology in their transformation plan using this model towards the Industry 4.0 concepts. Despite the improvement observed at this SME, the thesis also has some limitations and challenges. It was only conducted on one company representing one SME sector, which others may have different root causes related to the same problem. This thesis's findings and results have enabled the SME to work with the relevant agencies to request further assistance and support, including funding and other resources to transform towards Industry 4.0.