Volume 32(2) 2020
|1.||Applications of Machine Learning to Friction Stir Welding Process Optimization
Tauqir Nasir, Mohammed. Asmael*, Qasim Zeeshan & Davut Solyali
Machine learning (ML) is a branch of artificial intelligent which involve the study and development of algorithm for computer to learn from data. A computational method used in machine learning to learn or get directly information from data without relying on a prearranged model equation. The applications of ML applied in the domains of all industries. In the field of manufacturing the ability of ML approach is utilized to predict the failure before occurrence. FSW and FSSW is an advanced form of friction welding and it is a solid state joining technique which is mostly used to weld the dissimilar alloys. FSW, FSSW has become a dominant joining method in aero-space, railway and ship building industries. It observed that the number of applications of machine learning increased in FSW, FSSW process which sheared the Machine-learning approaches like, artificial Neural Network (ANN), Regression model (RSM), Support Vector Machine (SVM) and Adaptive Neuro-Fuzzy Inference System (ANFIS). The main purpose of this study is to review and summarize the emerging research work of machine learning techniques in FSW and FSSW. Previous researchers demonstrate that the Machine Learning applications applied to predict the response of FSW and FSSW process. The prediction in error percentage in result of ANN and RSM model in overall is less than 5%. In comparison between ANN/RSM the obtain result shows that ANN is provide better and accurate than RSM. In application of SVM algorithm the prediction accuracy found 100% for training and testing process.
Keywords: Machine learning; Artificial Neural Network; Support Vector Machine; ANFIS; Response Surface Methodology
|2.||A Study on Following Behavior Based on the Time Headway
Ehsan Ramezani Khansari, Masoud Tabibi* & Fereidoon Moghadas Nejad
While time headway (TH) is a relatively simple variable and has been well researched, it has been less explored in non-lane-based traffic. The main aim of this paper is considering lateral distance in studying TH in a non-lane-based traffic flow. In this study driving behavior, speed-TH relationship, and the following threshold by using only TH in a non-lane-based flow were investigated. In a novel approach, THs were segmented into five intervals in a step by step manner from smallest to largest THs. Considering lateral distance led to divide driving behavior into intervals (based on the average TH), including: Unsafe (0-0.7 sec), non-lane-based car-following (0.9 sec), lane-based car-following (1.0 sec), overtaking TH (1.3 sec), and free driving (larger than 2.5 sec). It was founded that the TH of starting overtaking maneuver can be a good criterion to distinguish between following and free driving behavior. Also, in lane-based car-following behavior, when lateral distance between the following and preceding vehicles was not considerable, the smallest THs were seen. It has happened around the average speed of the flow as the driver may adopt lower THs because of the tendency to overtaking. Linear relationship was found between TH and lateral distance in non-lane-based car-following conditions. TH of non-lane-based behavior is less than lane-based and smaller THs would force drivers to apply lateral distance or vice versa.
Keywords: Time headway, Driving behavior, Non-lane-based behavior, Free driving
|3.||Simulation and Control of a Six Degree of Freedom Lower Limb Exoskeleton
Mohammad Soleimani Amiri, Rizauddin Ramli*, Mohd Aizat Ahmad Tarmizi, Mohd Faisal Ibrahim & Khashayar Danesh Narooei
In this paper, the development of controlling a six Degree of Freedom (DOF) Lower Limb Exoskeleton (LLE) model using the Robot Operating System (ROS) is presented. Moreover, this work proposes a method to analyze kinematic properties and control of the LLE before the prototype. The model of the LLE is described using Extensible Markup Language (XML) programming in the Unified Robot Description Format (URDF). The dynamic equation of the six-DoF LLE is determined by using Newton-Euler. In addition, a Proposition-Integral-Derivative (PID) controller is established in a feedback closed-loop control system. The PID controller is tuned via Ziegler-Nichols (Z-N). The tuned PID controller is tested in the Gazebo environment to confirm the performance of the proposed method. The nodes and topics flow chart of the programmed 3-D model of the LLE is described. Furthermore, a desired angular trajectory based on the phase on walking is defined for each joint of the LLE. The result shows that the actual pursue the desired angular trajectory for each joint. The average and maximum error of the angular trajectories for all the joints are less than 0.05 radian. It can be ascertained that our developed LLE model in the Gazebo simulator can be used for giving an overview of the walking pattern.
Keywords: Robot Operating System (ROS); 3-D simulation; Gazebo; Lower Limb Exoskeleton; Newton-Euler; rehabilitation robotics
|4.||Extraction of Cellulose and Microcrystalline Cellulose from Kenaf
Yoong Li Hua, Shuhaida Harun*, Mohd Shaiful Sajab, Jamaliah Md Jahim & Siti Syazwani Mohd Shah
Bast and core of kenaf which categorized as agriculture residues were used in the extraction of cellulose due to its lignocellulosic nature. In this study, cellulose was extracted from the raw kenaf by using 10% alkaline peroxide pre-treatment followed by extraction process at 85 °C using the combination of 20% (v/v) formic acid and 10% (v/v) hydrogen peroxide that formed peroxy acid. The extracted cellulose was further hydrolyzed by 1.5 M of hydrochloric acid at 80 °C to yield microcrystalline cellulose (MCC). Relatively high yield of 71.81% (w/w) and 94.8% (w/w) were achieved for extracted cellulose and MCC, respectively. Based on FESEM, the average diameter of kenaf cellulose and MCC were 12.43 μm and 11.64 μm, respectively with the separated fibrils and rod-like structural. FT-IR spectral peaks observed in the cellulose and MCC revealed that most hemicellulose and lignin were eliminated during the chemical treatments. XRD analysis results exhibited that kenaf MCC gives the sharpest and highest peak s compared to others. The results also showed that the crystallinity index of extracted cellulose and MCC were increased to 60.5% and 62.3%, respectively.
Keywords: Kenaf; Cellulose; Microcrystalline cellulose (MCC); Alkaline hydrogen peroxide, Peroxy acid
|5.||‘SMART’ Manufacturing Method of Oleochemical Plants by Determining Fatty Acid Composition of C12 of Palm Kernel Stearin using Fuzzy Logic System
Vitiyah Manimaran, Norliza Abd. Rahman* & Jarinah Mohd Ali
Industry 4.0 is the name given to the latest evolution in the digitalisation and automation of manufacturing processes. Transitioning to Industry 4.0 is an emerging imperative for chemical processing based manufacturers throughout the world. “Smart” equipments, products and factories are transforming how companies do business, both internally and with suppliers and customers. At the present moment palm oil products particularly, Palm Kernel Oil have become a major feedstock for the oleochemical industries in Malaysia. Since Malaysia accounts for 42% of the global production of palm oil products, it is inevitable that the oleochemical industries has been flourishing and blooming in the last few years. The majority fatty acid found in palm kernel stearin is C12 which can be found in range of 54.8 to 64.0 wt%. But this value is determined by the iodine and saponification value of the palm kernel. The higher the iodine and saponification value, hence the higher the fatty acid composition can be found for higher extraction for oleochemical plant. The iodine value (Wjis) is ranged from 5.8 to 8.1 whereas the saponification value is ranged from 245 to 254 mgKOHg-1oil. Fuzzy Logic system is developed to determine the fatty acid composition for the different range of iodine value and saponification value to ensure kernel with different composition of fatty acid to be separated and produce higher purity of oleochemical substances. This system will ensure ‘SMART’ manufacturing replacing the ‘NON-SMART’ methods where all kernels are grinded randomly and extracting altogether.
Keywords: ‘SMART’ manufacturing , fuzzy logic
|6.||Comparative Analysis of Wastewater Treatment Technologies
Mukhtar Nuhu Yahya*, Hüseyin Gökçekuş & Dilber Uzun Ozsahin
The aim of this study is to apply the principle of multi-criteria decision-making (MCDM) theories on different types of wastewater treatment technologies. An increase in the production and discharge of wastewater is increasing; therefore wastewater treatment alternatives are needed. With increase in population growth, urbanization and industrialization increasing the amount of pollutants in our environments that leads to more wastewater discharge from both domestic and industries. These wastewaters are produced in large volumes and must be absolutely treated before discharge. Therefore, there is need for wastewater treatment technologies that are cost effective, easy to maintain, low energy use etc. This study will use some criteria on Fuzzy PROMETHEE to analyze the wastewater treatment technologies based on these criteria. The outcome of the decision-making theories in these wastewater technologies will help the concern parties in chosen the best among these technologies and will give an insight to these concerned parties such as engineers, town planners and other government personnel’s in making decisions. The common and most commonly used wastewater treatment technologies were evaluated and are compared based on certain criteria using fuzzy PROMETHEE decision-making theory and Nano-filtration Method is recommended the best followed by Activated Sludge (AS) Method based on this research.
Keywords: Wastewater Treatment Technologies; Fuzzy PROMETHEE; multi-criteria decision-making
|7.||Modelling and Simulation of the Performance Analysis for Peltier Module and Seebeck Module using MATLAB/Simulink
K.N. Khamil, M.F.M. Sabri*, A.M. Yusop, R. Mohamed & M.S.Sharuddin
Currently, the technologies used in power generation are not fully optimised and inefficient. The waste energy produced from the machines, systems and the infrastructure have created interest in energy harvesting researches especially the world is entering the Industrial Revolution 4.0 (IR4.0). This paper investigates the analytical modelling for both Peltier and Seebeck module in terms of the main parameters needed for quick evaluation depending on user’s application such voltage, current, coefficient of performance and the efficiency, thermal resistivity, total internal resistance, and Seebeck coefficient of the module. These parameters are normally given by manufacturer of the module through the datasheet. MATLAB/Simulink was used to simulate from the base equations. Graph representation of the output can be generated using several codes on Matlab command window. The simulation was tested on TEP1-1994-3.5 and TES1-05350 where the results obtained agrees well with the datasheet provided by the manufacturer which proved the MATLAB/Simulink’s modelling. The real experiment data using Peltier Module, APH-127-10-25-S proved the analytical modelling with the percentage error between simulation real experiments of 0.45% where the analytical simulation estimates the voltage output is 1.6340 V while the experimental voltage output from the in-lab experiment is 1.6266 V at hot temperature of 61°C and cold temperature of 27.5°C.
Keywords: peltier; seebeck; analytical modeling; thermoelectric; matlab; simulink
|8.||Simulation Study on Liquid Droplet Size Measurement inside Venturi Scrubber
Nur Tantiyani Ali Othman*, & Simreth Kaur Dhalywala
Droplet distribution is an importance factor to observe scrubber’s performance as uniform droplets distribution improved the particle’s collection efficiency at minimal liquid usage. Yet, the optimization problem typically involves complicated model functions to predict particle’s collection efficiency and pressure drop. Since the interaction between liquid droplets and gas phase is complex and difficult to solve by an experimental approach. Thus in this study, the prediction of liquid droplet’s behavior in the venturi scrubber was observed by using computational fluid dynamic. The liquid was injected through two orifices on the throat wall. The droplet size at different position was observed at various range of a gas velocity from 70 to 100 m/s and the ratio of liquid to gas of 0.07 to 2.0 L/m3 to determine the optimum absorption rate. The droplet’s breakup in the venturi scrubber was observed using ANSYS© simulation where two-fluid model Eulerian-Eulerian approach was applied. It shows as the gas passes through the throat section, the velocity increases gradually and as it passes through the divergent section, it decreases causing the droplet diameter to increase. Typically, the gas velocity in the throat section is between 30-120 m/s, however in this simulation, the gas velocity of 70-105 m/s shown an adequate to achieve the optimum absorption rate. Besides, the liquid to gas ratio less than 0.06 was insufficient to cover the throat, and by increasing it up to 1.0 does not significantly improve the particle collection efficiency as the velocity at the scrubber’s throat drops which a larger droplets diameter was formed.
Keywords: Droplet distribution; venturi scrubber; ANSYS© CFX; phase separation; gas velocity
|9.||Fire-Induced Flow Temperature Distribution Beneath a Ceiling
Razieh Khaksari Haddad & Mohammad Rasidi Rasani & Zambri Harun*
Many tunnels have been built to reduce traffic volumes in densely populated urban areas. In this research, a series of small-scale experiments were carried out in a 3 m length model tunnel with 0.6 m width and 0.95 m height to examine the temperature distribution along the tunnel ceiling. The containers for the source of the fire in this study were six different sizes of pools filled with n-heptane and gasoline. The smoke maximum temperature has been investigated experimentally and theoretically beneath the tunnel ceiling. A few results are obtained, firstly, dimensional analysis proposed in this research resulted in a theoretical estimation model for predicting maximum gas temperature under the ceiling. Then, the results from theoretical equation were compared with experimental data and an acceptable prediction was presented. The temperature distribution and smoke emission relationship with various ventilation velocities and heat release rate (HRR) were analyzed. The results show that an increase in ventilation velocity leads to temperature decrease and the fire source with higher HRR causes higher maximum smoke temperature. Furthermore, since the maximum temperature and the gas temperature decrease beneath the ceiling of the tunnel during the fire affect the tunnel structure, these parameters were also considered. Experimental results were also compared with that of Kurioka’s model. Empirical correlations for flow temperature decay along the tunnel were also proposed based on experimental data.
Keywords: Tunnel fire management; longitudinal ventilation velocity; temperature decay empirical prediction
|10.||Electrocardiogram-based Parameters for the Prediction of Sudden Cardiac Death: A Review
Shaliza Jumahat*, Norbahiah Misran, Gan Kok Beng, Mohammad Tariqul Islam & M.A.M Yahya
There has recently been a resurgence of interest in electrocardiogram-based (ECG-based) parameters in predicting Sudden Cardiac Death (SCD) risk. Accurate and timely SCD predictions are essential clinical practice for physicians to provide effective prevention and treatment. An ECG is a non-invasive and inexpensive diagnostic test, and has been firmly established as a clinical tool for assessing the risk of cardiac disease. The electrocardiographic signal derived from the ECG recording consists of a distinctive waveform that depicts the electrical activity of the heart, which can be analyzed for the identification of abnormalities in the heart rhythm. The parameter or characteristic found in the ECG signal might be important for predicting the SCD. A number of systematic reports by expert meetings and review articles in indexed journals identified ECG-based parameters as QRS duration, QT interval, Signal Average ECG (SAECG), T-wave alternan (TWA), Heart Rate Variability (HRV), Heart Rate Turbulence (HRT), T-peak to T-end (Tpe), fragmented QRS complexes (fQRS), and Early Repolarization (ER). This article reviews the mechanism and morphology of these parameters, which may potentially have a role to play in a future algorithm designed to identify early signs of SCD. As of now, none of the ECG-based parameters have been found to be sufficiently stable to predict the SCD risk. Nevertheless, the combination of two or more of the parameters listed, as suggested in many studies, may become a useful component for predicting SCD in the future.
Keywords: SCD prediction; electrocardiogram signal; ECG-based parameter, automated ECG analysis
|11.||Initial Assessment of Indoor Environmental Condition and Thermal Comfort of Malaysia Heritage Mosque
Wardah Fatimah Mohammad Yusoff*
Heritage mosques are the gems of the country as they preserve the history of local communities and nation. Many studies have been executed on the architectural characteristics of Malaysia heritage mosques. However, the empirical studies on its indoor environmental condition and thermal comfort are still lacking. Therefore, the objective of this study is to identify the indoor environmental condition and thermal comfort of Malaysia heritage mosque by using the field measurement method. The selected heritage mosque for this study is Masjid Tanah, which is located at Masjid Tanah, Alor Gajah, Melaka. Two multiparameter ventilation meters were used in the field measurement. The variables measured were air temperature and air velocity, while the indoor predicted comfort temperature was calculated using the adaptive thermal comfort model equation. The results show that the average indoor air temperatures were lower than the average outdoor air temperatures throughout the measurement. This is also similar with the indoor air velocities which were lower than the outdoor wind speeds at all times. Meanwhile, the results also demonstrate that the average indoor air temperatures were also lower than the indoor predicted comfort temperatures during the morning hours until 1 pm. The overall findings indicate that the architectural characteristics of the selected heritage mosque has a good response to the local climate. However, some improvements are necessary in enhancing the indoor thermal comfort. The findings can be used as guides for achieving a more comfortable indoor environmental condition of heritage mosques, as well as the modern mosques also.
Keywords: Heritage mosque; Indoor environmental condition; Thermal comfort; Air temperature; Air velocity
|12.||An Approach to Work Design: In-Depth Audit to Determine the Modifiers of Musculoskeletal Disorder Symptom Among Vehicle Maintenance Personnel
Shukriah Abdullah, Baba Md Deros, Nor Kamaliana Khamis*, Jaharah A. Ghani & Sholehah Abdullah
Vehicle maintenance personnel maintain, install, dismantle and repair as well as use hand tools in the nature of their job. A study in this domain has its complexities as there are not many research regarding the vehicle maintenance industry. The purpose of this paper was to identify the factors and their relationships towards the development of musculoskeletal disorder (MSDs) among vehicle maintenance workers. Using a self-reported questionnaire, 150 participants from workshops in Malaysia were involved in this study. They consisted of 50 workers maintain cars, 50 workers maintain four-wheel vehicles, and 50 workers maintain buses. The exclusion criterion was the participant has not been involved in accidents that caused injuries such as bone fractures as well as tears in joints, ligaments, and muscles for the past 12 months. Statistical analysis was performed to assess the impact of risk factors on MSD prevalence. Through regression analysis, it was revealed that psychosocial, temperature, and posture factors were associated with symptoms of MSD prevalence with p < 0.05. Age, working hours, type of vehicle repair and body mass index also showed a significant relationship with MSD prevalence. Concerning the sources of risk, related factors, mechanism of injury, and potential intervention strategies to reduce the risk, this paper will focus on the causes, nature, severity, and degree of work-relatedness of MSDs. This identification of risk factors among vehicle maintenance workers can be used to better characterise the magnitude of the problem and formulate targeted prevention strategies with improved surveillance and more accurate data collection.
Keywords: Mechanic worker; automotive; maintenance; safety; health
|13.||Rumble Strips: A Human Factors Perspective towards a Sustainable Road System
Shahren Ahmad Zaidi Adruce & Donald Stephen
Prior research substantiates the belief that human factors contribute to up to 90% of all traffic accidents. The failure to consider cognitive ergonomics in road safety initiatives will continue to cause traffic fatality, especially on straight roads. Since drivers and road safety practitioners cannot wholly avoid driver’s non-compliance, skill-based errors, and mistakes, road designs should aim to reduce the severity of repercussions resulting from human errors. For example, in the case of a momentary lapse of attention leading to lane departure, drivers should be able to correct their maneuvers. A human-centered traffic system approach of road design may reduce the severity of accidents caused by human error. An investigation of road crashes in Malaysia conducted by the Malaysian Institute of Road Safety Research revealed that 66% of road crashes in Malaysia are opposite-direction head-on crashes and run-off-road (roadway departure) crashes. Installing Lane Departure Warning System such as Centerline Rumble Strips (CLRS) and Shoulder Rumble Strips (SRS) can reduce these types of crashes and compensate human errors on the road. Rumble strips alert drivers that they are deviating from their lane by providing both tactile and auditory warnings. Although the effectiveness of rumble strips is well documented in prior researches, the practice of installing rumble strips is still scarce in Malaysia. This paper highlights how rumble strips can mitigate the consequences of the human errors, in the hope that the information can help road safety researchers, authorities, and practitioners move forward in the implementation of interventions towards sustainable road system.
Keywords: Sustainable Development Goal, Road Safety, Centerline Rumble Strips, Shoulder Rumble Strips, Human Factors
|14.||Corrosion Resistance Evaluation of Acrylic Coating Incorporated With Henna Leaves Extract
Mohammad Fakhratul Ridwan Zulkifli*, Mohd Sabri Mohd Ghazali, Mohd Ikmar Nizam Mohamad Isa, Suriani Mat Jusoh, Akihiro Yabuki & Wan Mohd Norsani Wan Nik
The study employs optical measurements, electrochemical studies and mechanism evaluations of an acrylic coating incorporated with henna leaves extract (HLE) at ambient temperature. The effect of concentrations variation of HLE in acrylic coating was investigated and acrylic coating with 0.2 wt/vol% (AC2) of HLE had the best performance protecting aluminium alloy 5083 from corrosion. Characterization through Fourier Transform Infrared Spectroscopy (FTIR) demonstrates the association of the carbonyl group of lawsone with the acrylic resin polymer via chain scission. A further deconvolution method was used in the range of 1550 – 1720 cm-1 and the complexation between HLE and acrylic coating was observed due to the shifting of carbonyl peak. AC2 shows the lowest water permeability value due to the compact structure and high density of the HLE colloidal system. Coating resistance shows an increasing trend upon incorporation of HLE and reaches the maximum resistance at AC2. A circuit fitting analysis of electrochemical impedance spectroscopy (EIS) indicates that all coated samples is represented by [(RfQdl)(RctQdl)(W)] circuit. Warburg impedance, W for AC2 shows the lowest value (1.21 × 10-7 Ω.s-1/2) in comparison to the other samples which indicates lower speed of diffusion. Suggested mechanism shows that HLE in AC2 was formed in a close pack structured in which providing a greater barrier effect towards corrosion susceptibility of aluminium alloy 5083.
Keywords: Acrylic resin coating; Corrosion additive; Electrochemical; Optical studies
|15.||Preliminary Study of Effective Copper Indium Sulfide (CuInS2) Quantum Dots as Photo-sensitizer in Solar Cell
Nurul Syafiqah Mohamed Mustakim, Javad Safaei, Charles Ahamefula Ubani, Suhaila Sepeai, Norasikin Ahmad Ludin, Mohd Asri Mat Teridie & Mohd Adib Ibrahim*
Recent studies showed that quantum dots (QDs) materials such as cadmium (Cd) and lead (Pb) are commonly used as sensitizer in solar cell applications. This is mainly because they have high potential in light harvesting. However, these materials are highly toxicity and very harmful to the environment. Therefore, current investigation reports the performance of quantum dots sensitized solar cells (QDSSCs) based on non-toxicity CuInS2 QDs by using solvothermal process. TiO2 paste were deposited by doctor blade method on transparent conducting fluorine doped tin oxide (FTO) glass substrates. The CuInS2 nano sized QDs were controlled by different solvothermal reaction times of 2 hours, 4 hours, 6 hours and 8 hours. In this study, the morphology, structural and optical properties of prepared TiO2/CuInS2 QDs thin films were investigated by using Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM), X-ray Diffraction (XRD) and Ultra-Violet-Visible Near Infrared Spectrophotometer (UV-Vis). The diameter of CuInS2 QDs was found to be increased from 3.19 nm to 8.67 nm with longer reaction time. Results showed that CuInS2 QDs with longer reaction time produced higher conversion efficiency. Based on the experiment done, CuInS2 QDs with 8 hours reaction time produced the best power conversion efficiency; 0.035 %. Regarding the considerable efficiencies obtained, pointed out that CuInS2 QDs can be introduced as an effective photosensitizer for making efficient QDSSCs devices.
Keywords: Copper Indium Sulfide; Non-toxic; Quantum dots; Solar cell; Solvothermal method
|16.||Model Pemulihan Sistem Inventori yang Mengalami Gangguan Bekalan dan Ketidakpastian Kualiti
Nurul Anis Mohd Sudin, Hawa Hishamuddin*, Muhammad Idham Sabtu, Hilmi Hisyam Naimin & Nurhadi Siswanto
Risiko gangguan rantaian bekalan boleh berlaku berdasarkan pelbagai senario yang mengakibatkan gangguan hampir tidak dapat dielakkan. Kajian terdahulu tidak mempertimbangkan ketidakpastian terhadap kualiti yang boleh dipengaruhi oleh gangguan bekalan tersebut. Kajian ini membangunkan model pemulihan pengeluaran bagi satu peringkat pengeluaran dan sistem inventori yang mengalami gangguan bekalan dan ketidakpastian kualiti. Sistem inventori berkemungkinan mengalami pelbagai jenis gangguan seperti gangguan rantaian bekalan, gangguan pengangkutan dan gangguan berdasarkan kualiti produk yang dihasilkan. Oleh itu, pihak pengurusan perlu membuat keputusan yang pantas dan efisien bagi mengatasi masalah gangguan tersebut dengan mempertimbangkan kos yang paling minimum. Model pemulihan ini dibangunkan bagi membantu pihak pengurusan dalam membuat keputusan yang tepat dan tidak merugikan pengeluaran semasa gangguan berlaku. Contoh berangka digunakan untuk membentangkan pengujian keberkesanan dan manfaat model matematik bagi mengatasi masalah gangguan bekalan dan ketidakpastian yang disebabkan oleh proses pengeluaran. Seterusnya, model tersebut dioptimumkan dengan menggunakan perisian LINGO. Kajian ini menujukkan bahawa jadual pemulihan yang optimum diperolehi berdasarkan peratusan produk yang mengalami masalah kualiti dan juga parameter kos yang lain. Sekiranya peratusan produk rosak pada pengeluaran meningkat turut mengakibatkan berlakunya peningkatan keseluruhan kos. Maka, model kajian ini dilihat berpotensi sebagai alat dalam membantu pihak pengurusan membuat keputusan yang tepat pada pelan pemulihan apabila berlakunya gangguan bekalan.
Kata Kunci: Gangguan rantaian bekalan, Ketidakpastian kualiti, Model inventori.Abstract English
The risk of supply chain disruptions can occur from a variety of events that make disruptions almost inevitable. Previous studies did not consider the quality uncertainty that can be affected by supply shortages. This paper presents a disruption recovery model for a single stage production and inventory system with consideration of disruption and quality uncertainties. The inventory system may experience a variety of disruptions such as supply chain disruptions, transportation disruptions and interruptions in the quality of the product. Therefore, management must make decisions quickly and efficiently to overcome these disruptions with minimum cost possible. The disruption recovery model was developed to help managers in making the right decisions and without affecting the production when the interruptions happen. Numerical examples are used to illustrate and examine the effectiveness and benefits of the mathematical model in solving the problem of supply disruption and quality uncertainty caused by the production process. Next, the model is optimized using LINGO software. This study showed that the optimal recovery schedule obtained is dependent on the percentage of products that have quality problems as well as other cost parameters. If the percentage of damaged goods in the production increases, the overall cost for recovery will also increase dramatically. Thus, the proposed model is seen to be a very useful tool to help managers make the right decisions on the optimal recovery plan during disruption occurences.
Keywords: Supply chain disruption; Quality uncertainty; Inventory model.
|17.||Persepsi Orang Awam dan Profesional terhadap Imej Visual Bandar Putrajaya
Fazlena Abd. Rahim* & Mohamed Mohamed Tolba Said
Putrajaya merupakan pusat pentadbiran kerajaan Persekutuan yang mana di awal pembangunannya telah dirancang sebagai bandar Islamik. Objektif kajian ini adalah menganalisis imej visual persekitaran alam bina yang memberikan identiti kepada Putrajaya menerusi persepsi orang awam dan profesional. Modenisasi dan kurang jelas tafsiran seni bina Islamik telah mewujudkan krisis identiti dalam gaya seni bina, kecelaruan identiti dan menjejaskan identiti reka bentuk bandar Islamik. Kajian ini menggunakan metodologi campuran kuantitatif dan kualitatif. Kajian soal selidik terhadap lebih kurang 500 orang awam dan temu bual bergambar terhadap lebih kurang 100 orang profesional dalam bidang alam bina telah dijalankan untuk untuk menganalisis imej visual identiti Putrajaya. Hasil kajian mendapati reka bentuk bandar Putrajaya mempunyai nilai estetik yang tinggi dan budaya Islam melalui ciri Islamik Timur Tengah bagi merealisasi penerapannya sebagai bandar Islamik. Bagaimanapun, gaya moden yang mendominasi, campuran dan kepelbagaian serta kurangnya identiti tempatan mewujudkan identiti yang kurang jelas dan budaya tersendiri yang lemah. Penemuan kajian ini boleh dimanfaatkan untuk memperkasakan imej visual bandar Putrajaya yang jelas sebagai bandar Islamik yang mempunyai identiti tempatan dan tersendiri untuk meningkatkan daya tarikan kepada pengguna bandar.
Kata kunci: bandar Islamik, reka bentuk bandar Islamik, imej visual, identiti, persepsi, orang awam, profesionalAbstract English
Putrajaya is the federal government’s administrative center which at the beginning of its development was planned as an Islamic city. The objective of this study is to analyze the visual images of the built environment that give the identity of Putrajaya based on public and professional perceptions. Modernization and lack of understanding of the interpretation of Islamic architecture has resulted in an identity crisis in the architectural style, misleading identity and affected the identity of the Islamic city. This study adopts both quantitative and qualitative methods. A questionnaire survey involving 500 civilians and photo-base method interviews with 100 professionals in the field of built environment was conducted to analyze the identity and the visual image of Putrajaya. The findings show that Putrajaya’s urban design has a high aesthetic value and Islamic culture through the Islamic Middle East features to realize its application as an Islamic city. However, the style of modern that dominates, mixture, diversity and lack of local identity creates a misleading and a weak of cultural identity. The findings of this study can be utilized to strengthen the visual image of Putrajaya city as an Islamic city with its own local identity and identity to increase attractiveness to urban users.
Key words: Islamic city, Islamic urban design, visual image, identity, public perception, professional perception
|18.||Moldability of Nano Size Zirconia for Powder Injection Molding Process by Using PEG and PMMA Binders
Al Basir*, Abu Bakar Sulong, Etta Eshak, Najlaa Nazihah Mas’ood, Nashrah Hani Jamadon & Norhamidi Muhamad
Powder injection molding (PIM) is a well-known manufacturing technique for the production of metal and ceramic near net shapes. Now-a-days, this technology is largely used in electronics, biomedical, aerospace, automotive, defence and telecommunication industries. In this paper, green parts of ZrO2 with polyethylene glycol (PEG), polymethyl methacrylate (PMMA) and stearic acid (SA) binders were prepared by PIM process. The average particle size of ZrO2 powder was 50 nm with pycnometer density of 6.054 g/cm3. The ZrO2 powder was mixed with binder content of 73 wt.% PEG, 25 wt.% PMMA and 2 wt.% SA. The rheological results showed pseudoplastic properties of the feedstock at 140 °C and 160 °C, which was suitable for PIM process. The suitable injection molding parameters for feedstock at 51 vol.% powder loading such as mold temperature, injection temperature, injection pressure and holding time were 60 °C, 160 °C, 10 bar and 8 s, respectively. At the same powder loading, the green part density of 3.60 g/cm3 was measured, whereas for the three-point flexural, the measured strength was in the range of 13-15 MPa. For structural analysis, the morphological properties of the powder as well as the surface and the cross-section of the green part was examined.
Keywords: Powder injection molding; Zirconia; Green part; Density
|19.||Investigation of Disruption Management Practices and Environmental Impact on Malaysian Automotive Supply Chains: A Case Study Approach
Noraida Azura Md Darom, Hawa Hishamuddin*, Rizauddin Ramli, Zulkifli Mohd Nopiah & Ruhul A Sarker
Much focus on managing a supply chain in the event of disruption has been on the financial consequences and the service level impact on the customers. The negative impact caused by the disruption could influence a company’s profit and market share. Nonetheless, the importance of the environmental impact consideration in the supply chain disruption management has not been emphasised in the existing literature despite research findings that highlight the impact of some resilient supply chain practices on its environmental sustainability. This paper aims to assess the relationship between supply chain mitigation and recovery practices and its environmental impact. To achieve this objective, a case study was employed where semi-structured interviews were conducted at selected automotive companies in Malaysia. The results show that most disruption mitigation and recovery practices of a supply chain have a medium impact on its environmental performance. In particular, the production process during supply disruption recovery has the highest influence on environmental performance in the form of waste generation and use of energy. The results of this study can be used by supply chain managers to focus their efforts in the right direction in order to achieve cost objectives, service levels and environmental goals during the management of disruptions.
Keywords: Supply Chain Disruption Management; Mitigation and Recovery Practices; Environmental Impact; Case Study
|20.||Clustering Approach on Layout Redesign to Optimize Container Handling Process
Container Terminal of Semarang is a service provider for export and import container handling process. It represents one of the divisions of PT (Persero) Port of Indonesia III Branch TanjungEmas Semarang. As an anticipatory step to growth of containership capacity in Port of Indonesia III Semarang, the company need to improve the quality of container handling service and to reach a higher level of productivity. One of the ways to achieve these goals is to focus on layout planning and management that can potentially be beneficial to all factors involved such as space exploitation, process efficiency etc. The layout planning of a container terminal can significantly benefit from using Group Technology approach in which containers can be grouped into families of containers and transported between cells(block locations in the yard).With this type of layout, the company has many advantages like flexibility on production process to address high variability in the system. As a result, it can give alternative arrangement of container in the yards. We observed that based on Bond Energy Algorithm (BEA) method, container travel distance can be reduced to 188.06 metres/ month, which is approximately 9 % saving of distances travelled by each container. Moreover, using Group Technology approach can provide a higher flexibility to cope with fluctuations in process.
Keywords: optimisation, group technology, container terminal