Theses & Dissertations

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

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  • Publication
    A novel lean manufacturing mathematical assessment tools using set theory in energy sector
    ( 2019)
    Malek Khalaf Salem Albezuirat
    Lean manufacturing assesments have become fundamentally significant for companies that seek to identify problems, identify the sources of the problems, and present effective ways through which these problems can be solved through practices of lean manufacturing. Thus, the present study aimed at developing an initial step that contributes to the transformation of lean applications, and assessments of the logic of artificial intelligence through set theory with the aim of facilitating the identification of practices and their actual impact. The study also amined at extending the application of lean manufacturing practices assessments in the energy sector, especially in thermal power plants, renewable power plants, nuclear power plans, electric transmission companies, and electric distribution companies. Therefore, the study was conducted based on the main objectives which are: I) To develop mathematical logic for improving the lean manufacturing assessment tools. ii) To design a novel lean manufacturing mathematical methods and set theory. iii) To test the validity and reliability of a novel lean manufacturing mathematical assessment through a real-life case study of the Jordanian energy sector. iv) To identify the types of wastes and sources of wastes in the energy sector and appropriate LMPs and the weight of their effect on the energy sector. The goals were achieved by using the "Set Theory" to develop the mathematical logic that can facilitate the efficiency and accuracy of the design process of assessments. The main hypotheses of the study were developed based on the identification of wastes, source of waste, and lean manufacturing practices that could be used for waste disposal in the energy sector. The mathematical logic was based on an association between quality, quantity and the hierarchical analysis in different processes in energy systems.This logic was then applied in the process of designing the assessment of practices in the real-life case study. The effectiveness of the mathematical logic was confirmed by the precise results obtained, whereby the results showed that the mathematical model is able to identify waste, source of waste and lean manufacturing practices accurately. Based on the study findings, a comprehensive description of practices that can be used in the energy sector was presented. More specifically, the findings demonstrated a clear difference between the nature of waste and lean manufacturing practices depending on the different operations of companies within the energy sector. Another difference is in the actual value of the impact of the application of lean manufacturing practices according to the type of lean manufacturing practice. In addition, the mathematical logic that was developed can be applied in the evaluation process in other sectors with ease and clarity to ensure more effective results. These results can be used to the design smart assessment systems through software programs such as Python and Matlab applications in future studies.
      5  11
  • Publication
    A study of quality tools and techniques employed in Perlis and Kedah manufacturing companies
    ( 2010)
    Che Padzilah Yaacob
    Quality tools and technique can be used to achieve continuous improvement of quality in the manufacturing industry. This research is focused on manufacturing companies located in the states of Perlis and Kedah. The study examines whether manufacturing companies employ quality tools and techniques in their daily operations. In addition, it identifies the problems and challenges faced during the implementation of the tools and techniques on the manufacturing shop floor. The study uses mail questionnaires and structured interviews as its main instruments of data collection. In this study four hypotheses are developed based on the theoretical framework, of which the variables are in the categories of independent, dependent and moderating variables. Independent variables comprise of company location, number of years the company has been operating (referred to as “level of maturity”), annual sales turnover, number of full time employees, product(s) of the company, and quality standard certification. Meanwhile, the dependent variables are the issues in the implementation of quality tools and techniques, and how quality tools and techniques help the companies. Moderating variables in this research are the actual use of quality tools and techniques and information regarding the respondents who answered the questionnaire on behalf of the company. Data was analysed using independent T-Test and one-way analysis of variance (ANOVA) and the results helped to identify the problems and challenges faced during the implementation of the tools and techniques. The findings of this study reveal that quality tools and techniques are indeed being used by the companies but each with varying degree. The results reveal that companies that implement ISO 9000 quality system tend to use more quality tools and techniques compared to companies without quality systems. The study indicated that high sales turnover has no impact on planning, budget and training as well as the implementation of quality tools and techniques. It also indicates that the level of maturity does not have any bearing on the implementation of quality tools and techniques. Lastly, higher numbers of work forces do not necessarily bring about issues of communication and teamwork in order to implement quality tools and techniques in the company. In conclusion, the overall results from this study show that training, teamwork, communication, planning, and budgeting have no impact at the companies in Perlis and Kedah.
  • Publication
    A study on corrosion resistance of Sodium Metavanadate (NaVO₃) coated on AZ91D Magnesium alloy by anodizing technique
    ( 2015)
    Nor Fadzilah Toha
    Anodizing also known as anodic oxidation coatings have attracted significant interest in the study because of their potential to improve the corrosion resistance of alloys. Anodic oxidation coatings are usually chosen for special applications heavy duty corrosion resistance is required. Previously, chromate compounds were widely used for producing conversion coatings to protect most metallic surfaces such as aluminum, steel and magnesium alloys. In spite of its toxicity hexavalent chromate (IV) has remain an essential ingredient in the metal finishing industry for corrosion control. But combining the economic impact of corrosion damage, the environmental and health problems caused by hexavalent chromate (IV), and the increasing the regulatory restrictions, scientists have a huge incentive to develop a new generation of environmentally friendly protective coating systems. The objective of this research is to determine the corrosion resistance of AZ91D magnesium alloy utilizing sodium metavanadate (NaVO₃). Besides, to study on surface microstructure, thickness, surface roughness and chemical composition related to the coating and its contribution to corrosion performance. Then, investigate the corrosion behavior and corrosion protection mechanism of AZ91D magnesium alloy. Sodium metavanadate (NaVO₃) is used as anelectrolytesolution to form coating in this research.
  • Publication
    Adhesive joint strength of dissimilar metal adherends by Taguchi Method
    ( 2019)
    Nurul Atikah Datu Derin
    The dissimilar metal joints are widely used in many applications. A lot of efforts have been made to study the joining techniques in order to achieve a reliable dissimilar joint for unlike metals including welding. However, dissimilar welding methods is facing critical failure because of the differences in thermal expansion between the different metals. This research is concerned with the investigation of joining dissimilar metal between stainless steel and carbon steel by adhesive joining technique. Adhesive bonding has the advantage and ability to joint different types of material. The main purpose of this study is to investigate the effect of heat treatment on medium carbon steel (AISI 1045) and stainless steel (AISI 304) and its effect on adhesive bonding strength. An experimental approach has been made to attain the research purpose with respects to these factors; adherend mechanical properties, surface treatment and adhesive thickness. The mechanical properties were controlled by using several heat treatment processes, annealing for stainless steel whilst annealing, normalizing, and quenching was done on carbon steel. Surface treatment was controlled by using sandpaper at 180, 500, and 1000 grit. Lastly, an alignment jig was used to control the joint geometry to have an aligned butt-joint specimen and to have a 0.5mm, 1.0mm, and 1.5mm adhesive thickness. The adhesive used in this investigation is Araldite, a slow-setting epoxy adhesive; it consists of two components which are resin and hardener manufactured by Huntsman Corporation and the specimens were divided into three groups which were named as as-received (AR), sequence 1 (SQ1) and sequence 2 (SQ2). Each group has nine numbers of experiments which were carried out by using Taguchi Method. Three specimens were prepared for each experimental condition. A total of 81 tensile tests at room temperature have been carried out under axial tensile test by Universal Testing Machine (UTM). Signal-to-noise ratio (SNR) and analysis of variance (ANOVA) analysis was used to find the optimal parameter setting resulting the highest tensile strength of adhesive bonded butt-joint specimen. Other tests were also done on adherend which are surface roughness and visual examination to find the relation or underlying reason for the analysis results. Based on ANOVA results, it was found that the contribution of adhesive thickness is 59.38%, which is higher than abrasive paper, 28.76% for AR group. For SQ1 group, the factors influencing the tensile strength in descending order are abrasive paper, 26.09% followed by adhesive thickness and heat treatment with 24.12% and 12.71% respectively. While the main factors influencing the tensile strength in SQ2 are adhesive thickness 67.51%, followed by the abrasive paper with 12.80% and then heat treatment 11.00%. This result shows that the heat treatment process have insignificant influence on adhesive butt-joint strength of AISI 1045 and AISI 304.
  • Publication
    Allelopathic potential of essential oils isolated from local plants on common weeds found in Malaysian croplands
    ( 2017)
    Ahmed Abdulwahid Ali AlMarie
    Continuous use of the synthetic herbicides to control weeds in agricultural production can have an adverse impact on the environment and the ecosystems creating safety and health concerns to the operators, consumers and the community. However, it is the resistance to the synthetic herbicides that developed in the targeted weeds and its consequent that provide strong justification for the need to develop an eco-friendly, natural and low risk but effective alternative bioherbicides. The study thus explores the benefits of using plant’s allelopathic potential that manifested in its essential oil, as an alternative herbicide. The research involved the isolation of the essential oils from eight selected plant species of Cupressus macrocarpa Hartweg. (Goldcrest), Melaleuca bracteata F. Muell. (Tea tree), Plectranthus amboinicus (Lour.) Spreng (Spanish thyme), Cymbopogon nardus L. (Lemongrass), Pelargonium radula Cav. (Radula geranium), Baeckea frutescens L. (Cucur atap), Murraya koenigii L. (Curry tree) and Persicaria odorata (Lour.) Sojak (Kesum plant) by steam distillation. Isolated essential oils were screened for their herbicidal activity as preemergence applied at three concentrations on two major weed types (2 grassy and 2 broad leaves weed species) grown under bioassay laboratory and pot culture conditions. The compounds were characterized using GC-MS. The phytotoxic effects of the eight essential oils were also evaluated on the four weeds as postemergence by analyzing the total chlorophyll content, relative electrolyte leakage, cellular respiration and stomata mechanism in the leaf membrane. The most effective essential oils were then evaluated as postemergence by applying singly and in a combination of two essential oils on widely known weed grown in the open field and compared with the known synthetic herbicide, Halexone (H130) as a control. The best essential oils were selected based on their efficacy of more than 70 % inhibition. The results showed that the oils isolated from C. macrocarpa, C. nardus and P. radula were the most effective in inhibiting seed germination and seedling growth completely in laboratory bioassay and caused the most severe effects on weeds grown under the pot culture. GC-MS analysis showed monoterpene was the most dominant and effective component of all essential oils followed by sesquiterpene and phenylpropanoids. The phytotoxic experiment showed total chlorophyll content, relative electrolyte leakage and cellular respiration were significantly affected by the application of the bioherbicides. The effects increased by increasing the oil concentration. There was a significant influence of the essential oils on plant membranes affecting the stomata mechanism, rupturing cell membrane, dissolution of its contents which eventually kill the weeds. The application of essential oils as postemergence herbicides to weed grown in the open field showed desirable efficiency against the weeds as non-selected contact bioherbicides comparable with the performance of the conventional synthetic herbicides H130. Application of the essential oils formulated in combinations improved the phytotoxic effects as compared to using oils singly. The combination of C. macrocarpa and P. radula at 5% each proved to produce the best phytotoxic effects in suppressing weed population.
      3  12
  • Publication
    An energy absorption characterization of improved circular thin-walled tubes under dynamic loading
    ( 2013)
    Masniezam Ahmad
    Thin-walled tube is one of the energy absorber devices designed to dissipate energy and increase the efficiency of a crashworthiness structure in an impact event. During an accident, thin-walled tube dissipates the kinetic energy of the structure and converts the kinetic energy into the other form of energy thus minimize the impact experienced by the occupant. This research examines the thin-walled tube subjected to axial dynamic crushing experiment by using a drop weight impact tester. A nonlinear finite element model for the tube crushing has been developed by using LS-DYNA software and a good agreement has been achieved between the finite element model and experimental results. The parametric studies of the thin-walled tubes have been performed by using the validated FE model. The analysis of energy absorption characteristics includes the energy absorption capacity, initial peak load, specific energy absorption (SEA) and crush force efficiency (CFE) results. The shape, material and geometry of the tube are varied to investigate the effect of using these parameters to the energy absorption characteristics. As a result, circular tube is capable to provide better energy absorption characteristics compared to the square tube. The tubes designed by three different materials which are aluminium alloy AA6061-T6, carbon steel S1214 and magnesium alloy AZ31B-O has been developed in LS-DYNA. It was found that the magnesium alloy AZ31B-O is highly potential to be created as the thin-walled tube material instead of aluminium alloy and carbon steel since it has excellent result in initial peak load, SEA and CFE. However, when the applications neglect the damage of the structure and does not involving human, carbon steel is the best material as it can absorb most energy capacity and high mean crushing force. The effect of length, diameter and thickness of the tube to the energy absorption characteristics has been investigated. It was concluded that initial peak load and CFE are optimum in thicker and larger tube. Energy absorption capacities are optimum in thicker, larger and longer tube while SEA result is optimum in thicker, smaller and shorter tube. At the end, the modifications performed on the original tube shows an improvement in the energy absorption characteristics compared to the current tube designs. A combination of conical tube with flat end cap was proposed as the best modified tube since it has excellent results on initial peak load, CFE and SEA with moderate results on the energy absorption capacity. Research information provided in this study will serve as a guide to design the thin-walled tube in the future.
  • Publication
    An investigation of fatigue crack growth behavior of UIC 54 profile in high speed railway applications
    ( 2017)
    Gurubaran Panerselvan
    The safety of wheels and rails is a greater concern for the Malaysian railways Keretapi Tanah Melayu and manufacturers of the railway network. The rolling contact fatigue (RCF) is a growing problem due to increase of the high speed train operation in Malaysia and increased of load cycle. The RCF is defined as a damage that occurred due to the change in the material microstructure which contributes to crack initiation followed by crack propagation under the influence of time-dependent. The typical cracks originating at the running surface is called as head check. The transverse cracks leading to the eventual fracture of the rail. As well as the crack growth rate is higher, it caused the crack to propagate faster and initiate the sudden rail failure at any time. In this study, numerical analysis of stress–strain characteristics of three dimensional (3D) wheel-rail contact was successfully carried out by ANSYS Workbench 14.5. Apart from that, this study focuses on the fatigue strength and fatigue crack growth (FCG) of UIC 54 profile. The fatigue strength and FCG study were coordinated with the dog-bone specimen (ASTM E-466- 15) and compact tension (CT) specimen (ASTM E-647-15), respectively. The S-N curve was plotted from 7 data of the dog-bone specimens to evaluate fatigue strength with a constant stress ratio 0.1, and variable in applied stress levels. In addition, the rail profile of UIC 54 fatigue strength was validated with simulation result by ANSYS Workbench 14.5. The simulation works were executed with dog-bone specimen model according to the experimental applied stress level. Meanwhile for FCG the study was conducted with the CT specimens with a variable in stress ratio of 0.1, 0.3 and applied loads of 16 kN and 13 kN. The material crack growth rate for UIC 54 profile is obtained from Paris– Erdogan relationship C and m. The maximum von–Mises stress result for the wheel and rail contact was obtained higher at rail gauge corner region and it’s exceed the yield strength limit (533 MPa) of UIC 54 profile. Furthermore, the equivalent plastic stress result reveals that most of the plastic deformation occurs at the rail gauge corner region, on the contrary almost very small plastic deformation occurs at the wheel. The overall hardness measurement for used rail obtained was 37.9 % greater than unused rail. The hardness value for P1 (used rail) indicates that rail gauge corner region was affected by high contact stresses and plastic strains.
  • Publication
    An investigation on the effects of AI₃ O₃ nanolubrication system with surfactant on tool wear and surface roughness in turning process
    ( 2016)
    Mohamed Asyraf Mahboob Ali
    Application of nanolubricants can improve machining performance since the rolling action of billions of nanoparticles at the tool-chip interface leads to less friction; which can produce superior surface quality and longer tool life. The combination of nanolubricants with minimum quantity lubricant (MQL) systems in machining, minimize the consumption of lubrication oil; consequently, less pollution will be caused. Nanolubricants is a lubrication alternative to improve machining output, a cost saving and less harmful cutting lubricant to human and nature. However, the superiority of nanolubricants is limited, due to the agglomeration of nanoparticles, which leads to sedimentation of nanoparticles after a period of time. The addition of a surfactant can lower the agglomeration of nanoparticles and stabilize the nanolubricants for a longer period. But, lack of study on the performance of nanolubricants with surfactant restricted the fundamental understanding on their effect on mechanics of machining process. Hence, to investigate the effectiveness of aluminum oxide (Al2O₃) nanolubricants with Sodium Dodecylbenzene Sulfonate (SDBS) surfactant, experimental investigations have been attempted in this study while machining titanium alloy, Ti-6AL-4V. For a better penetration of nanoparticles into cutting region, nanolubricants was supplied with MQL system
  • Publication
    Analysis urban farming management system in Petaling Jaya city council
    ( 2022)
    Muhammad Hisyamuddin Shahrin
    Urban farming is a type of agriculture practiced in areas that are mainly populated by people. It involves the production of food and earning. Urban farming is beneficial for the environment and food security. Due to the high land value in the area, it is necessary to identify the suitable lands for farming. Petaling Jaya City Council has established Kebun Kita to promote community farm in Petaling Jaya. There are many research regarding benefit of urban farming but there a lack of study on management element in urban farming. Community farm in urban area need effective management system to ensure they are giving high impact and benefit toward community and stakeholder. This paper is dealing with the analysis on urban farming management in Petaling Jaya using Malaysia Business Excellence Framework from the perspective of Sustainable Index Urban Agriculture, SIUA that derived from Urban Farming Program objective under Malaysia Department of Agriculture. This paper identifies the factors and examine the relationship between this factors and SIUA. Policy implication also provided based on the research findings.
      10  3
  • Publication
    Analyzing factors of influencing consumer behaviour during Covid-19 pandemic outbreak: a case study in Perlis
    ( 2022)
    Ahmad Tarmizi Mohd Asarani
    This study was designed to analyze factors influencing consumer behaviour in Perlis during COVID-19 pandemic outbreak. A sample of 266 civil servants in Perlis answered questions about ICT use, pandemic-related reactions and actions, demographics, and psychosocial factors via an online survey as well as physical questionnaires. The statistical tests that were conducted in this research included demographics via frequency analysis, Cronbach’s Alpha test for the questionnaire reliability, correlation analysis to test the strength of the relationship between variables, and regression analysis for finding the relationship between the mentioned factors with the dependent variable. In this context, the research found that all independent variables namely pandemic outbreak, ecommerce, and ICT applications have positive relationship with consumer behaviour changes during COVID-19. Overall, results are consistent with the idea that technology is a coping tool that shifts the consumer behaviour perspectives and balanced use can lead to feelings of less future anxiety during the pandemic. This study also supports the idea that civil servants economically remain unaffected during a pandemic based on the survey result that shows their tendency to fully utilize e-commerce platforms despite COVID-19. Therefore, the analysis in this research can help authorities to align consumerismrelated policies during pandemics based on consumers’ buying and health considerations through ICT channels in the future.
  • Publication
    Application of DMAIC six sigma in manufacturing field: case study in yield improvement in production
    ( 2022)
    Jadatharan S Shunmuga Velu
    This research here addresses the improvement of first pass yield on the production floor of ABC Semiconductor. ABC is a company running a multiple volume complex product in alignment with the memory business in the operation. First pass yield refers to the proportion of fully built products that pass testing without the need for additional rework. The first pass yield (FPY) project began in 2015 and showed steady progression for its first five years. But over the following years, the primary yield metric which is first passed yield has stayed stagnant. The goal of the paper presented here is to analyze the reasons for the current performance and propose novel ways of improving the metric again using quality management tools. In this research, multiple quality tools have been demonstrated to enable the quality improvement recommendation which is classified as the statistical and systemic approach is being presented. The most common is using the 7QC tools method by categorizing failure pareto that will lead to targeted corrective action to reduce the recurrence of pre-identified failure modes. A DMAIC methodology is established on how to define an efficient corrective action, along with a top-three major defect on data acquired from the ABC organization.
  • Publication
    Assessment on Lean implementation in the Malaysia semiconductor manufacturing industry
    ( 2020)
    Foo Wai Seng
    One of the main issue with the different industries today is to manufacture exceptional quality products or produce best of class services with minimal cost spending as well as working towards waste reduction throughout the process of production. These and many other industries related problems had led to the formation of Lean manufacturing, a concept that was initially implemented by Toyota of Japan which mostly known as Toyota Production System. Concept of Lean manufacturing was widely spread across countries and industries because of higher living standard nowadays causes rising customer's expectation and fierce competition among industry players due to market globalization. With benefits gain from Lean principles, it helps company to survive during fluctuating demand in the market and improve quality of product at lower cost of expenditure. This research project is an attempt to investigate reasons associated with lean adoption in Small and Medium Enterprises (SMEs), popularity lean practices in use from the range of 13 lean practices and present strategic department to start lean within SMEs organization that constitutes a successful lean implementation at semiconductor manufacturing in Malaysia. Survey questionnaire is prepared to collect detail information on popularity of 13 lean practices identified, reasons of lean adoption and strategic department to start lean in SMEs from the target population of respondents. The response of 102 respondents were received and by applying statistical analysis to determine result of this research study. Results of study showed SMEs have a high understanding of the importance of lean application within SMEs. One of the main contributors is because semiconductor industry is one of the most dynamics with very fast changing in product models and customers demand behaviour as compare to other industries. Most popular lean practices are closely tied to SMEs capabilities such as least capital investment cost, easy to apply and produce immediate effect. Result of this research study would provide good reference and guidelines to SMEs for a successful implementation of lean and better insight of lean adoption within SMEs in the semiconductor manufacturing industry in Malaysia.
      2  10
  • Publication
    Autonomous maintenance decision model for lathe machine using fuzzy analytical hierarchy process (AHP) method
    ( 2015)
    Ahmadi Hamdan Musman
    Deterioration on production machine may lead to high production costs. One of the preventive maintenance strategies to reduce deterioration of machine is Autonomous Maintenance (AM). The aim of autonomous maintenance is to achieve a high degree of cleanliness, excellent lubrication and proper fastening on the machine. However, the conventional AM practice, the process of initial cleaning might increase the maintenance cost and the time required. Therefore, to make this process more effective and efficient, this study proposes an AM decision model using fuzzy Analytical Hierarchy Process (AHP) method to identify the critical components and to determine the right AM activities. A case study of a lathe machine is used to validate the model. The data were collected through personnel interview with technicians at machine shop laboratory in UniMAP. In this study, fuzzy AHP is carried out using pairwise comparison data to verify the critical components. Finding of the analysis reveals that there are eight critical components of the lathe machine that have been identified. By having this information, the model does help in minimizing the maintenance costs and time by identifying the right component for maintenance and so to determine the right maintenance activities to be carried out. Thus, this study has provide theoretical and practical inferences about the development of AM decision model.
  • Publication
    Burst strength and impact performance on glass fibre reinforced epoxy (GRE) composite pipes
    ( 2016)
    Hawa Ahmad
    While in service environment, the changes in the degradation mechanisms of the GRE composite pipes may occur in the matrix, fibre, and the fibre-matrix interfacial regions due to water diffusion. These composite pipes may also be subjected to impact loads, during manufacturing, installation or while in service. This research involves an experimental investigation of the deformation and failure on unaged and aged GRE composite pipes through the impact loadings and monotonic burst tests. Pipes were aged in tap water temperature at 80°C for periods of 500, 1000 and 1500 h in order to simulate in service environments, while trying to obtain reliable results from accelerated laboratory tests. At the end of ageing condition period, the pipes were impacted at room temperature for three different energy levels, which are 5 J, 7.5 J and 10 J before subjected to monotonic burst tests. The hyperbolic tangent model produced better predictions of moisture diffusion rate to the experimental results. From the experimental results and mathematical analysis, it was evident that the modulus of GRE pipes were significantly degraded (27% in axial and 15% in hoop direction) due to water diffusion. The results indicated that as the impact energy increase the peak force, displacement and absorbed energy also increased. The increased absorbed energy signifies that more energy was consumed in damage growth of the pipes. The impacted pipes have been subjected to moisture absorption content above 1% yielded lower burst strength and the ratio of the residual burst strength also reduced rapidly by about 50%. Weepage and eruption failures were observed depending on the applied impact energies.
  • Publication
    Characterization and biodegration study on Cellulose nanocrystals isolated from rice straw/polyvinyl alcohol nanocomposites
    ( 2022)
    Chin Kwok Mern
    This research investigates the extraction of cellulose from rice straw, which is an agricultural waste product to produce CNC and its utilization for the development of biodegradable and environment friendly nanocomposite films. CNC extracted from rice straw through cyclic alkaline and bleaching treatment method appeared as long, welldefined rodlike crystals with high aspect ratio of 41. Polyvinyl alcohol (PVOH), a popular biodegradable and biocompatible polymer was chosen as the polymer matrix. PVOH/CNC bionanocomposite films were made through employing solution casting method with different weight percentages to determine the optimum CNC weight percentage (wt%). It was found that 3 wt% CNC incorporation vastly improved the tensile strength by 60.4%, maximum degradation temperature to 287 ºC, water vapor permeability rate and swelling and solubility resistance of PVOH/CNC. The optimum CNC amount was found to be at 3 wt%. In order to address the issue of hydrophilicity and diversify the use of the bionanocomposite, a more versatile bionanocomposite was developed with the introduction of ethanedioic acid (EA) as a crosslinker. Crosslinked nanocomposite displayed significant improvements where tensile strength increased by 104.8%, maximum degradation temperature to 364 ºC, water vapor permeability rate, solubility and swelling resistance. Finally, biodegradation study is an appealing investigation for the development of a more efficient and environmentally friendly plastic waste disposal. The current work also aimed to study the biodegradation behavior and its degrading bacterias of noncrosslinked and crosslinked PVOH/CNC bionanocomposites through natural soil burial method. The degrading bacterias were isolated and identified to be Bacillus cereus strain CCM 2010 and Bacillus cereus strain ATCC 14579 from 16S rRNA gene sequencing. The changes in functional groups before and after biodegradation were confirmed through Fourier-transform infrared spectroscopy. Tensile test revealed that the tensile strength and elongation at break reduced as time of soil burial increases. Morphological study showed the extent of surface deterioration of bionanocomposites before and after soil burial, where the addition of EA displayed lessened deterioration. Total weight loss also decreased after crosslinking occurred. Melting temperature and crystallinity increased with addition of CNC but reduced after crosslinking. Melting temperature and crystallinity of all nanocomposites increased after biodegradation for all bionanocomposites. Biodegradation of the bionanocomposites were concluded to be in the following decreasing order: PVOH/CNC > PVOH/EA/CNC > PVOH > PVOH/EA.
  • Publication
    Characterization and optimization of indoor environmental quality on Grey oyster (Pleurotus pulmonarius) mushroom cultivation
    ( 2017)
    Md Tariqul Islam
    In view of increasing demand, mushroom cultivators are facing more challenges and difficulties to grow mushroom due to inconsistent environmental conditions. Controlling and monitoring of environmental quality in mushroom cultivation is an important factor for high mushroom production. Therefore, this study was initiated to examine the suitability and growing performance of P. pulmonarius in indoor environmental condition. For this, the experimental design was followed by two different procedures as characterization and optimization of the indoor environment. Characterization procedure was conducted by mushroom cultivation in five different environmental conditions including from System 1 to System 5. The substrate for mushroom growing was prepared by mixing of sawdust, rice bran and agricultural lime for the all cultivation systems and spawn was inoculated. After completing mycelium colonization the experimental mushroom cultivations were conducted by System 1 to System 5. System 1 was the natural indoor environment whereas from System 2 to System 5 were the indoor humidifying environment with or without ventilation. The lowest mean indoor temperature and the highest mean humidity was found in System 3 which showed significant results with all other systems. The highest morphology and outstanding moisture containing fruitbodies were also found in System 3. The highest 98.4% primordial initiation and 98.6% mature fruitbodies formation with the lowest 1.4% dead primordia were found in System 3. The lowest 30.2% primordial initiation was found in System 1. The lowest 43.1% and 42.4% mature fruitbodies and the highest 56.9% and 57.6% dead primordia were found in System 4 and 5 respectively. The highest bio-efficiency (73.6%) of yield was achieved in the cultivation of System 3. The optimization procedure was conducted under two different environmental conditions as named System 6 and System 7. System 6 was followed by the procedure of System 3 with additional numbers of the humidifier, ventilation, and substrate bags. For this, the humidifiers and ventilations were applied by one combined and five individual treatments to optimize the humidifying duration and cultivation procedure. On the other hand, outdoor cultivation was conducted as System 7 for comparison study. The optimized configuration was found as the application of 15 mins humidifying treatment and followed by 15 mins interval period for each humidifier. The lowest temperature and highest humidity were found in System 6.The morphology and moisture contents of fruitbodies were found significantly high in System 6, where the total yield was found 261.8 kg which was 140.3 kg higher than System 7. The temperature showed significant negative correlation and the humidity showed significant positive correlation with the morphology and moisture contents of fruitbodies.
      2  14
  • Publication
    Classification of stainless steel and mild steel using vibration technique
    ( 2011)
    Intan Maisarah Abd Rahim
    The production of material in industry must attain some standard such as the standard required by American Society for Testing and Materials (ASTM) International. The requirement of the material standard is important in some crucial field such as aerospace, engineering and automotive. This research presents a development of a material classification scheme with non-destructive testing on the material to classify the material type. The classification of the material can be useful in post-production verification. Many testing methods have been developed to reach the standard of the material production. The testing of the material mechanical properties using vibration technique could determine the natural frequencies, the damping ratio and mode shapes of the structure. The testing method chose to be implemented in this research is impact hammer testing. Frequency Response Function (FRF) signals obtained from the testing and natural frequencies of the materials are extracted from FRF signals. In this research, the features considered as the input data for the algorithm training are the natural frequencies of the material and its amplitude. Later, the input data obtained are classified using Artificial Neural Network (ANN) with Levenberg-Marquardt Backpropagation and k-Nearest Neighbor (k-NN). Each of the classifier produced a different classification rate depending on the performance of the training input data set. The result from the classification system shows that k-NN is giving the accuracy of 99.69% with the k value of 3. While, Levenberg-Marquardt Backpropagation is giving the best classification rate of 99.43%.
  • Publication
    Closed-form solutions and stress analysis of stainless steel/aluminum hybrid joint
    ( 2017)
    Nur Athirah Mat Nawi
    Hybrid joints are a combination of adhesive bonding and mechanical fastening that are able to combine the advantages of both joint types. Today, hybrid joining is attractive in automotive applications as the technique can offer various benefits during manufacturing. A 3 mm thin plate of Aluminium A7075 and stainless steel 304 were used as the adherend material for experimental test and the adhesive used was high performance Araldite Epoxy adhesive. This research examines stainless steel/aluminium hybrid joints to be tested in two ways. First is by using ANSYS software application where it was employed to deal with stress analysis of the adhesive bonding of hybrid dissimilar joints using the finite element method. Hybrid dissimilar joint specimens were fabricated having five bond thicknesses; t (i.e., 0.4 mm, 0.8 mm, 1.2 mm, 1.6 mm and 2.0 mm). The effect of bond thickness was investigated by using the commercial finite element package in ANSYS. Various thicknesses of adhesive give different values of maximum von Mises stress. It is found that greater thickness results in higher maximum stress. Moreover, various thicknesses of adhesive also result in different values of deformation. This shows that more deformation occurs when the thickness of adhesive is increased. This analysis proves that increasing adhesive thickness reduces the joint strength, mainly because stress distribution is increased on adhesive surfaces. Before proceed to second approach, comparison between experiment and ANSYS was done. The purpose for this comparison is to prove that ANSYS analysis is similar with experiment and the result can be use. The second approach is to formulate a new equation using MATLAB tools for analysis of shear stress distribution along the bond line under effect of adherend thickness ratio and adherend Young’s modulus ratio. The solution is formulated based on the analysis of Paroissien Eric. The least stress intensities in the joint could be achieved with a suitable ratio of thickness and Young’s modulus of adherends. Result from both method ANSYS and analytical model were compared and the results were in agreement, which means that the analytical model can be used at least for the configuration considered in this study.
  • Publication
    Coated and uncoated drills performance evaluation in drilling NiTi alloys with different coolant-lubricant strategies
    ( 2020)
    Rosmahidayu Rosnan
    Nickel-titanium (NiTi) alloys have been outstanding and demandabe materials in several critical applications such as aerospace and biomedical industries, on accounts of their excellent mechanical and physical properties. Their inherent properties include superior strength-to-weight ratios, high mechanical strength, excellent corrosion resistance, and unique biocompatibility. However, NiTi alloys are considered to be difficult-to-machine due to poor thermal conductivity, high specific heat, and high strain hardening, which attributed to rapid tool wear and tool failure, as well as poor machined surface finishes. Given the facts that these alloys are quite unique and not yet well understood, a through analysis of the current state of NiTi machinability characteristics is required. Therefore, this experimental study was initiated to evaluate the performance of titanium aluminium nitride (TiAIN) coated and uncoated carbide drills with respect to tool wear, tool life, tool failure modes, thrust force, surface roughness, surface defects and dimensional accuracy under two different cutting conditions of flood coolants and minimum quantity nanolubricants (MQNL). Cutting speeds of 10, 20 and 30 m/min and constant feed rate of 0.02 mm/rev were employed in the aforementioned cooling and lubricating conditions. The results show that =t TiAIN coated carbide tools under MQNL condition outperformed the uncoated carbide tools under flood condition. It exhibited improvement of 9.68%, 88% and 75.49%, with respect to number drilled holes, tool life and also induced thrust force, respectively. Nonetheless, MQNL was found to produce rougher surface compared to flood conditions which resulted in several surface defects and higher average hole diameter.
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  • Publication
    Composite material manufacturing process improvement with the use of quality tools and lean six sigma techniques
    ( 2018)
    Masniza Yusof
    This study is focusing in the use of Quality Tools and Lean Six Sigma methodology in composite material manufacturing hand lay-up process improvement. Hand lay-up is a process in which individual layers of prepreg are laid up on a tool and then cured. Hand lay-up is a manual process that resulting in numbers of quality defects such as voids, delamination, warpage and the Foreign Object Debris (FOD). This study exclusively deals with the FOD quality defect. In this study some suitable quality tools along with Lean Six Sigma improvement process DMAIC (Define, Measure, Analyse, Improve, Control) approaches are applied on the hand lay-up process to provide a way to the company on how to reduce the numbers of FOD quality defects of composite panels to get high quality components which ultimately fit in the aircraft. The focus of this research is in demonstrating how to use quality tools and Lean Six Sigma improvement process DMAIC in practice. The potential FOD on the composite material have been studied. In order to validate the manufacturing system’s current state, statistical tools such as Pareto chart and histogram were used. To ensure that all the decisions were as heavily based on actual data as possible, the data collected had been analysed through Fishbone diagram and Failure Mode Effect analysis (FMEA). As the result of this research, the main source of the cause of the problem is identified and some solutions were purposed. These solutions included, Kaizen, Standard Operation Process and SMED. With the application of quality tools and lean six-sigma approaches it was found, the composite material manufacturing company was able to reduce the number of FOD defect and improve the overall performance of hand lay-up process.