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 CHIEF EDITOR Ahmad Faris Ismail, IIUM, Malaysia TECHNICAL EDITOR Sany Izan Ihsan, IIUM, Malaysia EXECUTIVE EDITOR AHM Zahirul Alam, IIUM, Malaysia ASSOCIATE EDITOR Nor Farahidah Za’bah, IIUM, Malaysia LANGUAGE EDITOR Lynn Mason, Malaysia COPY EDITOR Hamzah Mohd. Salleh, UNISSA, Brunei Darussalam MALAY TRANSLATOR Nurul Arfah Che Mustapha, IIUM, Malaysia   EDITORIAL BOARD MEMBERS Abdullah Al-Mamun, IIUM, Malaysia Abdumalik Rakhimov, IIUM, Malaysia Aishah Najiah Bt. Dahnel, IIUM, Malaysia Alya Naili Binti Rozhan, IIUM, Malaysia Norsinnira Bt. Zainul Azlan, IIUM, Malaysia Hanafy Omar, Saudi Arabia Hazleen Anuar, IIUM, Malaysia Konstantin Khanin, University of Toronto, Canada Ma'an Al-Khatib, IIUM, Malaysia Meftah Hrairi, IIUM, Malaysia Mohamed B. Trabia, United States Mohammad S. Alam, Texas A&M University-Kingsville, United States Mustafizur Rahman, National University Singapore, Singapore Ossama Abdulkhalik, Michigan Technological University, United States Mohamed Hadi Habaebi, IIUM, Malaysia Mohd. Sultan Ibrahim Bin Shaik Dawood, IIUM, Malaysia Muhammad Ibn Ibrahimy, IIUM, Malaysia Nor Fadhillah Mohamed Azmin, IIUM, Malaysia Waqar Asrar, IIUM, Malaysia   INTERNATIONAL ADVISORY COMMITTEE A. Anwar, United States Abdul Latif Bin Ahmad, Malaysia Farzad Ismail, USM, Pulau Pinang, Malaysia Hanafy Omar, Saudi Arabia Hany Ammar, United States Idris Mohammed Bugaje, Nigeria K.B. Ramachandran, India Kunzu Abdella, Canada Luis Le Moyne, ISAT, University of Burgundy, France M Mujtaba, United Kingdom Mohamed AI-Rubei, Ireland Mohamed B Trabia, United States Syed Kamrul Islam, United States Tibor Czigany, Budapest University of Technology and Economics, Hungary Yiu-Wing Mai, The University of Sydney, Australia.   AIMS & SCOPE OF IIUM ENGINEERING JOURNAL The IIUM Engineering Journal, published biannually (January and July), is a carefully refereed international publication of the International Islamic University Malaysia (IIUM). Contributions of high technical merit within the span of engineering disciplines; covering the main areas of engineering: Electrical and Computer Engineering; Mechanical and Manufacturing Engineering; Automation and Mechatronics Engineering; Material and Chemical Engineering; Environmental and Civil Engineering; Biotechnology and Bioengineering; Engineering Mathematics and Physics; and Computer Science and Information Technology are considered for publication in this journal. Contributions from other areas of Engineering and Applied Science are also welcomed. The IIUM Engineering Journal publishes contributions under Regular papers and Invited review papers. It also welcomes contributions that address solutions to the specific challenges of the developing world and address science and technology issues from an Islamic and multidisciplinary perspective.  REFEREES’ NETWORK All papers submitted to IIUM Engineering Journal will be subjected to a rigorous reviewing process through a worldwide network of specialized and competent referees. Each accepted paper should have at least two positive referees’ assessments. SUBMISSION OF A MANUSCRIPT A manuscript should be submitted online to the IIUM Engineering Journal website at http://journals.iium.edu.my/ejournal. The journal website could conduct further correspondence on the paper's status. Whilst the publisher and editorial board make every effort to see that no inaccurate or misleading data, opinion, or statement appears in this Journal, they wish to make it clear that the data and opinions appearing in the articles and advertisements herein are the responsibility of the contributor or advertiser concerned. Accordingly, the publisher and the editorial committee accept no liability whatsoever for the consequence of any such inaccurate or misleading data, opinion, or statement.    IIUM Engineering Journal ISSN: 1511-788X   E-ISSN: 2289-7860   Published by: IIUM Press, International Islamic University Malaysia Jalan Gombak, 53100 Kuala Lumpur, Malaysia Phone (+603) 6421-5014, Fax: (+603) 6421-6298

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Editorial

   CHIEF EDITOR Ahmad Faris Ismail, IIUM, Malaysia TECHNICAL EDITOR Sany Izan Ihsan, IIUM, Malaysia EXECUTIVE EDITOR AHM Zahirul Alam, IIUM, Malaysia ASSOCIATE EDITOR Nor Farahidah Za’bah, IIUM, Malaysia LANGUAGE EDITOR Lynn Mason, Malaysia COPY EDITOR Hamzah Mohd. Salleh, IIUM, Malaysia MALAY TRANSLATOR Nurul Arfah Che Mustapha, IIUM, Malaysia   EDITORIAL BOARD MEMBERS Abdullah Al-Mamun, IIUM, Malaysia Abdumalik Rakhimov, IIUM, Malaysia Aishah Najiah Bt. Dahnel, IIUM, Malaysia Alya Naili Binti Rozhan, IIUM, Malaysia Norsinnira Bt. Zainul Azlan, IIUM, Malaysia Hanafy Omar, Saudi Arabia Hazleen Anuar, IIUM, Malaysia Konstantin Khanin, University of Toronto, Canada Ma'an Al-Khatib, IIUM, Malaysia Meftah Hrairi, IIUM, Malaysia Mohamed B. Trabia, United States Mohammad S. Alam, Texas A&M University-Kingsville, United States Mustafizur Rahman, National University Singapore, Singapore Ossama Abdulkhalik, Michigan Technological University, United States Mohamed Hadi Habaebi, IIUM, Malaysia Mohd. Sultan Ibrahim Bin Shaik Dawood, IIUM, Malaysia Muhammad Ibn Ibrahimy, IIUM, Malaysia Nor Fadhillah Mohamed Azmin, IIUM, Malaysia Waqar Asrar, IIUM, Malaysia   INTERNATIONAL ADVISORY COMMITTEE A. Anwar, United States Abdul Latif Bin Ahmad, Malaysia Farzad Ismail, USM, Pulau Pinang, Malaysia Hanafy Omar, Saudi Arabia Hany Ammar, United States Idris Mohammed Bugaje, Nigeria K.B. Ramachandran, India Kunzu Abdella, Canada Luis Le Moyne, ISAT, University of Burgundy, France M Mujtaba, United Kingdom Mohamed AI-Rubei, Ireland Mohamed B Trabia, United States Syed Kamrul Islam, United States Tibor Czigany, Budapest University of Technology and Economics, Hungary Yiu-Wing Mai, The University of Sydney, Australia.   AIMS & SCOPE OF IIUM ENGINEERING JOURNAL The IIUM Engineering Journal, published biannually (January and July), is a carefully refereed international publication of the International Islamic University Malaysia (IIUM). Contributions of high technical merit within the span of engineering disciplines; covering the main areas of engineering: Electrical and Computer Engineering; Mechanical and Manufacturing Engineering; Automation and Mechatronics Engineering; Material and Chemical Engineering; Environmental and Civil Engineering; Biotechnology and Bioengineering; Engineering Mathematics and Physics; and Computer Science and Information Technology are considered for publication in this journal. Contributions from other areas of Engineering and Applied Science are also welcomed. The IIUM Engineering Journal publishes contributions under Regular papers and Invited review papers. It also welcomes contributions that address solutions to the specific challenges of the developing world and address science and technology issues from an Islamic and multidisciplinary perspective.  REFEREES’ NETWORK All papers submitted to IIUM Engineering Journal will be subjected to a rigorous reviewing process through a worldwide network of specialized and competent referees. Each accepted paper should have at least two positive referees’ assessments. SUBMISSION OF A MANUSCRIPT A manuscript should be submitted online to the IIUM Engineering Journal website at http://journals.iium.edu.my/ejournal. The journal website could conduct further correspondence on the paper's status. Whilst the publisher and editorial board make every effort to see that no inaccurate or misleading data, opinion, or statement appears in this Journal, they wish to make it clear that the data and opinions appearing in the articles and advertisements herein are the responsibility of the contributor or advertiser concerned. Accordingly, the publisher and the editorial committee accept no liability whatsoever for the consequence of any such inaccurate or misleading data, opinion, or statement.    IIUM Engineering Journal ISSN: 1511-788X   E-ISSN: 2289-7860   Published by: IIUM Press, International Islamic University Malaysia Jalan Gombak, 53100 Kuala Lumpur, Malaysia Phone (+603) 6421-5014, Fax: (+603) 6421-6298

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The Optimization of Growth Condition of the Bacteria Producing Cold-Active Proteolytic Enzyme from the Antarctic Region

The growth conditions of bacteria producing cold-active protease isolated from an Antarctic sample were screened using one-factor-at-time (OFAT). Then, crude protease of the strain was extracted during the late logarithmic phase for enzymatic assay. A strain that showed the highest enzyme activity was selected for optimization via response surface method (RSM). The parameters studied were incubation temperature (4 – 36 °C), pH media (4 – 10) and NaCl concentration (0 – 8%). Based on the OFAT results, all eight strains showed the highest growth rate at 20 °C, pH 7 and 4% (w/v) NaCl. The assay showed that the crude enzyme extracted from strain SC8 exhibited significantly higher activity (0.20 U and 0.37 U) than the positive control (0.11 U and 0.31 U) at -20 °C and 20 °C. RSM suggested that the optimized setting for growth of SC8 were at 20.5 °C, pH 6.83 and 2.05% (w/v) of NaCl with the results of the bacterial growth rate value was 3.70 ± 0.06 x 106 cells/hr. Optimal growth conditions of SC8 from this study are useful for the large-scale production of cold-active protease in future. ABSTRAK: Keadaan pertumbuhan bakteria yang menghasilkan enzim protease aktif sejuk daripada sampel Antartika disaring menggunakan satu faktor pada masa (OFAT). Kemudian, enzim protease ini diekstrak pada lewat fasa logaritma untuk ujian enzimatik. Strain yang menunjukkan aktiviti enzim tertinggi telah dipilih untuk tujuan pengoptimuman melalui kaedah permukaan tindak balas (RSM). Parameter yang dikaji ialah suhu pengeraman (4 – 36 °C), pH media (4 – 10) dan kepekatan NaCl (0 – 8%). Berdasarkan OFAT, kesemua lapan bakteria menunjukkan kadar pertumbuhan tertinggi pada 20 °C, pH 7 dan 4% NaCl. Hasil ujian enzimatik menunjukkan bahawa enzim protease yang diekstrak daripada SC8 mempamerkan aktiviti yang jauh lebih tinggi (0.20 U dan 0.37 U) daripada kawalan positif (0.11 U dan 0.31 U) pada -20 °C dan 20 °C. RSM mencadangkan tetapan optimum untuk pertumbuhan SC8 adalah pada 20.5 °C, pH 6.83 dan 2.05% NaCl dengan keputusan kadar pertumbuhan bakteria ialah 3.70 ± 0.06 x 106 sel/jam. Keadaan pertumbuhan optimum SC8 daripada kajian ini bermanfaat untuk menghasilkan produk protease aktif sejuk secara besar-besaran pada masa hadapan. The growth conditions of bacteria producing cold-active protease isolated from an Antarctic sample were screened using one-factor-at-time (OFAT). Then, crude protease of the strain was extracted during the late logarithmic phase for enzymatic assay. A strain that showed the highest enzyme activity was selected for optimization via response surface method (RSM). The parameters studied were incubation temperature (4 – 36 °C), pH media (4 – 10) and NaCl concentration (0 – 8%). Based on the OFAT results, all eight strains showed the highest growth rate at 20 °C, pH 7 and 4% (w/v) NaCl. The assay showed that the crude enzyme extracted from strain SC8 exhibited significantly higher activity (0.20 U and 0.37 U) than the positive control (0.11 U and 0.31 U) at -20 °C and 20 °C. RSM suggested that the optimized setting for growth of SC8 were at 20.5 °C, pH 6.83 and 2.05% (w/v) of NaCl with the results of the bacterial growth rate value was 3.70 ± 0.06 x 106 cells/hr. Optimal growth conditions of SC8 from this study are useful for the large-scale production of cold-active protease in future. ABSTRAK: Keadaan pertumbuhan bakteria yang menghasilkan enzim protease aktif sejuk daripada sampel Antartika disaring menggunakan satu faktor pada masa (OFAT). Kemudian, enzim protease ini diekstrak pada lewat fasa logaritma untuk ujian enzimatik. Strain yang menunjukkan aktiviti enzim tertinggi telah dipilih untuk tujuan pengoptimuman melalui kaedah permukaan tindak balas (RSM). Parameter yang dikaji ialah suhu pengeraman (4 – 36 °C), pH media (4 – 10) dan kepekatan NaCl (0 – 8%). Berdasarkan OFAT, kesemua lapan bakteria menunjukkan kadar pertumbuhan tertinggi pada 20 °C, pH 7 dan 4% NaCl. Hasil ujian enzimatik menunjukkan bahawa enzim protease yang diekstrak daripada SC8 mempamerkan aktiviti yang jauh lebih tinggi (0.20 U dan 0.37 U) daripada kawalan positif (0.11 U dan 0.31 U) pada -20 °C dan 20 °C. RSM mencadangkan tetapan optimum untuk pertumbuhan SC8 adalah pada 20.5 °C, pH 6.83 dan 2.05% NaCl dengan keputusan kadar pertumbuhan bakteria ialah 3.70 ± 0.06 x 106 sel/jam. Keadaan pertumbuhan optimum SC8 daripada kajian ini bermanfaat untuk menghasilkan produk protease aktif sejuk secara besar-besaran pada masa hadapan.

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Repurposing A Sampling-Based Planner for A Six-Degree-Of-Freedom Manipulator to Avoid Unpredictable Obstacles

This paper presents the use of a sampling-based planner as a reactive planning scheme to avoid obstacles between a robotic arm and a moving obstacle. Based on a planner benchmark on an obstacle-ridden environment,  a rapidly-exploring random tree (RRT) planner has been used to populate the trajectories of the task space and map them into a configuration space using a Newton-Raphson-based inverse kinematic solver. Two robot poses are defined in a cycle of back-and-forth motion; the initial and the goal poses. The robot repeatedly moves from the starting pose to the end pose via the midpoint pose. Each set of trajectories is unique. We define this unique solution within the context of the configuration space as a cycle space. We impose a periodically occurring synthetic obstacle that moves in and out of the robot arm workspace defined in a simulated environment. Within the robot's workspace, the obstacle moves and cuts through the cycle space to emulate a dynamic environment. We also ran a benchmark on the available sampling planner in the OMPL library for static obstacle avoidance. Our benchmark shows that the RRT has the lowest time planning time at 0.031 s compared with other sampling-based planners available in the OMPL library, RRT implicitly avoids singularities within the cycle space, and reactively attempts to avoid synthetic moving objects near the robot hardware. This research intends to further investigate on the use of RGB-D sensor and LiDAR to track moving obstacles while abiding by the task space commands described by the initial and goal poses. ABSTRAK: Kertas kerja ini membentangkan penggunaan perancang berasaskan persampelan sebagai skim perancangan reaktif untuk mengelakkan halangan antara lengan robot dan halangan yang bergerak. Berdasarkan penanda aras perancang pada persekitaran yang dipenuhi halangan, perancang pokok rawak (RRT) penerokaan pantas telah digunakan untuk mengisi trajektori ruang tugas dan memetakannya ke dalam ruang konfigurasi menggunakan penyelesai kinematik songsang berasaskan Newton-Raphson. Dua pose robot ditakrifkan dalam kitaran gerakan bolak-balik; pose awal dan matlamat. Robot berulang kali bergerak dari pose permulaan ke pose akhir melalui pose titik tengah. Setiap set trajektori adalah unik. Kami mentakrifkan penyelesaian unik ini dalam konteks ruang konfigurasi sebagai ruang kitaran. Kami mengenakan halangan sintetik yang berlaku secara berkala yang bergerak masuk dan keluar dari ruang kerja lengan robot yang ditakrifkan dalam persekitaran simulasi. Dalam ruang kerja robot, halangan bergerak dan memotong ruang kitaran untuk meniru persekitaran yang dinamik. Kami juga menjalankan penanda aras pada perancang pensampelan yang tersedia dalam perpustakaan OMPL untuk mengelakkan halangan statik. Penanda aras kami menunjukkan bahawa RRT mempunyai masa perancangan masa terendah pada 0.031 s berbanding dengan perancang berasaskan pensampelan lain yang terdapat dalam perpustakaan OMPL, RRT secara tersirat mengelakkan singulariti dalam ruang kitaran, dan secara reaktif cuba mengelakkan objek bergerak sintetik yang menghampiri perkakasan robot. Melangkah ke hadapan, penyelidikan ini berhasrat untuk menyiasat lebih lanjut mengenai penggunaan penderia RGB-D dan LiDAR untuk mengesan halangan bergerak sambil mematuhi arahan ruang tugas yang diterangkan oleh pose awal dan matlamat.

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Solar Thermal Process Parameters Forecasting for Evacuated Tubes Collector (ETC) Based on RNN-LSTM

Solar Heat for Industrial Process (SHIP) systems are a clean source of alternative and renewable energy for industrial processes. A typical SHIP system consists of a solar panel connected with a thermal storage system along with necessary piping. Predictive maintenance and condition monitoring of these SHIP systems are essential to prevent system downtime and ensure a steady supply of heated water for a particular industrial process. This paper proposes the use of recurrent neural network-based predictive models to forecast solar thermal process parameters. Data of five process parameters namely - Solar Irradiance, Solar Collector Inlet & Outlet Temperature, and Flux Calorimeter Readings at two points were collected throughout a four-month period. Two variants of RNN, including LSTM and Gated Recurrent Units, were explored and the performance for this forecasting task was compared. The results show that Root Mean Square Errors (RMSE) between the actual and predicted values were 0.4346 (Solar Irradiance), 61.51 (Heat Meter 1), 23.85 (Heat Meter 2), Inlet Temperature (0.432) and Outlet Temperature (0.805) respectively. These results open up possibilities for employing a deep learning based forecasting method in the application of SHIP systems. ABSTRAK: Penggunaan sumber bersih seperti Tenaga Solar dalam Proses Industri (SHIP) adalah satu kaedah alternatif untuk menhasilkan tenaga yang boleh diperbaharui bagi mengurangkan kesan gas rumah hijau yang terhasil dari proses industri. Sistem SHIP biasanya mengandungi panel solar dan sistem penyimpanan haba yang berhubung melalui paip yang sesuai. Penyelengaraan secara berkala diperlukan bagi memastikan sistem ini sentiasa membekalkan tenaga solar pada kadar bersesuaian dan bekalan tenaga solar yang terhasil berterusan dan tidak menjejaskan sistem pemanasan air bagi sesuatu proses industri. Kajian ini mencadangkan penggunaan model ramalan rangkaian neural berulang bagi meramal parameter proses pemanasan solar. Kelima-lima parameter proses iaitu – Iradiasi Solar, Suhu Saluran Keluar & Masuk Pengumpul Solar dan Bacaan Kalorimeter Fluks pada dua tempat diambil sepanjang empat bulan (dari Julai 2021 sehingga Oktober 2021). Dapatan menunjukkan dua varian RNN termasuk LSTM dan Unit Berulang dapat dibanding prestasinya bagi tugas ramalan ini. Dapatan kajian menunjukkan Ralat Punca Min Kuasa Dua (RMSE) antara bacaan sebenar dan ramalan adalah masing-masing 0.4346 (Iradiasi Solar), 61.51 (Meter Terma 1), 23.85 (Meter Terma 2), Suhu Salur Masuk (0.432) and Suhu Salur Keluar (0.805). Ini membuka peluang kajian mendalam berdasarkan kaedah ramalan dalam aplikasi sistem SHIP.

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Control Strategy for Power Assist Upper Limb Rehabilitation Robot with the Therapist’s Motion Intention Prediction

Currently, fully automated rehabilitation robots can assist therapists in providing rehabilitation therapy, hence the patients could get hurt. On the other hand, manual treatment may cause less patient injury but it is tiresome, and there are not enough therapists in most countries. Power assist rehabilitation robots can support the therapists in conducting the treatment and may help to alleviate this problem. The goal of this study is to develop a control strategy for the robot to assist the therapist’s movement in a power assist upper limb rehabilitation treatment. The system combines the advantages of robotic and manual rehabilitation therapy. Torque and position sensors fitted on the power assist upper limb rehabilitation robot arm are used for motion intention estimation. The amount of angular velocity necessary to be delivered to the feedback controller will be determined by predicting the therapist‘s motion intention using the impedance control method. The resulting velocity from the motion intention estimator is incorporated into the Sliding Mode Control - Function Approximation Technique (SMC-FAT) based adaptive controller. The SMC-FAT based adaptive controller in the feedback loop, overcomes the uncertain parameters in the combination of the robot and the human arm. The motion intention estimator forecasts the movement of therapists. The proposed controller is used to regulate elbow flexion and extension motion on a power assist upper limb rehabilitation robot with one degree of freedom (DOF). The proposed control system has been tested using MATLAB simulation and hardware experimental tests. The outcomes demonstrate the effectiveness of the proposed controller in directing the rehabilitation robot to follow the desired trajectory based on the therapist's motion intention, with maximum errors of 0.002rad/sec, 0.005rad/sec and 0.02rad/sec for sinusoidal, constant torque values, and hardware experiment respectively. ABSTRAK: Pada masa ini, robot rehabilitasi automatik sepenuhnya dapat membantu ahli terapi dalam menyediakan terapi pemulihan, tetapi pesakit berkemungkinan tercedera. Sebaliknya, rawatan manual berkemungkinan mengurangkan kecederaan pesakit tetapi ia memenatkan, dan terdapat kurang ahli terapi yang mencukupi di kebanyakan negara. Robot pembantu rehabilitasi dapat membantu ahli terapi dalam menjalankan pemulihan dan mengurangkan masalah ini. Sistem ini menggabungkan kelebihan terapi pemulihan robotik dan manual. Alat pengesan tork dan kedudukan diletakkan pada anggota atas lengan robot rahabilitasi yang digunakan bagi mengesan anggaran jarak pergerakan ahli terapi. Anggaran halaju sudut diperlukan bagi kawalan gerak balas dan dapat diketahui melalui anggaran niat gerakan ahli terapi menggunakan kaedah kawalan impedans. Halaju yang terhasil daripada anggaran niat gerakan diadaptasi ke dalam pengawal adaptif berasaskan Kawalan Mod Gelongsor - Teknik Anggaran Fungsi (SMC-FAT). Pengawal penyesuaian berasaskan SMC-FAT dalam gelung maklum balas, mengatasi parameter yang tidak pasti dalam gabungan robot dan lengan manusia. Penganggar niat gerakan meramalkan gerakan ahli terapi. Pengawal yang dicadangkan digunakan bagi mengawal lenturan siku dan gerakan lanjutan pada robot rehabilitasi dengan satu darjah kebebasan (DOF). Sistem kawalan yang dicadangkan telah diuji menggunakan simulasi MATLAB dan ujian eksperimen perkakasan. Dapatan kajian menunjukkan keberkesanan pengawal yang dicadangkan dalam mengarahkan robot rehabilitasi mengikut trajektori yang dikehendaki berdasarkan niat gerakan ahli terapi, dengan ralat maksimum masing-masing 0.002rad/s dan 0.005rad/s bagi sinusoidal, nilai tork malar, dan eksperimen perkakasan masing-masing.

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A Hybrid of Kansei Engineering (KE) And Analytical Hierarchy Process (AHP) to Develop Conceptual Designs of Portable Oil Spill Skimmer

Currently, there are huge demands on developing a design that fulfils the characteristics of performance, cost, safety, and aesthetics. However, the conceptual design stages in industrial products lack the involvement of user requirements as it is typically focused on the product's performance. Consequently, specific criteria such as the product's ease of use, safety, and robustness cannot be compared and measured when designing industrial products. Owing to this reason, this research proposes a new technique that integrates Kansei Engineering with Analytical Hierarchy Process (AHP) to address the issue. The research objective is to investigate an oil spill skimmer's user and technical requirements by incorporating the Kansei Engineering method. The approach to carry out this research is to incorporate the Kansei and the basic AHP methods. Kansei Engineering will suggest the required design elements that must be included to design and fabricate a portable oil spill skimmer. At the same time, the AHP method is used to select the best design based on the developed conceptual design. The effectiveness of the proposed method was verified by comparing it with other established methods, such as TOPSIS (Technique of Order Preference by Similarity to Ideal Solution). Moreover, sensitivity analysis was used to investigate the robustness of the AHP result. There are 5 conceptual designs in total, assessed in this research. The result showed that out of the 5 conceptual designs, design number 3 has the highest ranking (priority ranking = 0.2603). Thus, the most suitable conceptual design for the portable oil spill skimmer to be fabricated is design 3. The finding also shows that the result from AHP was valid and robust. ABSTRAK: Pada masa kini, terdapat permintaan besar bagi membangunkan reka bentuk yang memenuhi ciri-ciri prestasi, kos, keselamatan dan estetika. Walau bagaimanapun, industri kurang melibatkan keperluan pengguna pada peringkat reka bentuk konsep produk industri, kerana ia biasanya tertumpu pada prestasi produk. Ini menyebabkan kriteria khusus seperti kemudahan menggunakan produk, keselamatan dan keteguhan produk tidak dapat dibandingkan dan diukur semasa mereka bentuk produk industri. Disebabkan faktor berkenaan, kajian ini mencadangkan teknik baharu yang mengintegrasikan Kejuruteraan Kansei bersama Proses Hierarki Analitik (AHP) bagi menangani isu tersebut. Objektif kajian adalah bagi menyiasat keperluan pengguna dan keperluan teknikal menyaring tumpahan minyak dengan menggabungkan kaedah Kejuruteraan Kansei. Pendekatan kajian ini adalah dengan menggabungkan Kansei dan kaedah asas AHP. Kejuruteraan Kansei mencadangkan elemen reka bentuk yang diperlukan yang mesti disertakan bagi mereka bentuk dan menyaring tumpahan minyak mudah alih. Pada masa sama, kaedah AHP digunakan bagi memilih reka bentuk terbaik berdasarkan reka bentuk konsep yang dibangunkan. Keberkesanan kaedah yang dicadangkan telah disahkan dengan membandingkannya dengan kaedah lain yang telah terbukti, seperti TOPSIS (Teknik Aturan Kehendak Berdasarkan Persamaan dengan Solusi Ideal). Selain itu, analisis sensitiviti digunakan bagi mengkaji keteguhan keputusan AHP. Terdapat 5 reka bentuk konseptual yang dinilai dalam kajian ini. Dapatan kajian menunjukkan bahawa reka bentuk nombor 3 mempunyai keputusan tertinggi (keutamaan kedudukan = 0.2603) daripada 5 reka bentuk konseptual ini. Oleh itu, reka bentuk konsep yang paling sesuai bagi saringan tumpahan minyak mudah alih yang akan dibina adalah reka bentuk 3. Dapatan kajian juga menunjukkan bahawa hasil daripada AHP adalah sah dan kukuh.

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Analytical Model of Subthreshold Swing for Junctionless Double Gate MOSFET Using Ferroelectric Negative Capacitance Effect

An analytical Subthreshold Swing (SS) model is presented to observe the change in the SS when a stacked SiO2-metal-ferroelectric structure is used as the oxide film of a JunctionLess Double Gate (JLDG) MOSFET. The SS of 60 mV/dec or less is essential to reduce power dissipation while maintaining transistor performance. If a ferroelectric material with Negative Capacitance (NC) effect is used, the SS can be reduced below 60 mV/dec. The analytical SS model of the ferroelectric NC FET presented to analyze this was in good agreement with the SS derived from the relation between the drain current and gate voltage, using 2D potential distribution. As results were derived from the analytical SS model, it was found that it is possible to obtain an SS of 60 mV/dec or less even at 15 nm channel length by adjusting the thicknesses of the silicon channel, SiO2, and ferroelectric. In particular, the change in SS according to the ferroelectric thickness was saturated as the thickness of SiO2 increased and was almost constant as the thickness of the silicon channel decreased. ABSTRAK: Model Ayunan Subambang (SS) analitikal dibentangkan bagi melihat perubahan pada SS apabila struktur feroelektrik-logam-SiO2 bertindan digunakan sebagai filem oksida bagi MOSFET Dua Get Tanpa Simpang (JLDG). SS 60 mV/dec atau kurang adalah penting bagi mengurangkan pelesapan kuasa sambil mengekalkan prestasi transistor. Jika bahan feroelektrik dengan kesan Kapasitans Negatif (NC) digunakan, SS dapat dikurangkan bawah 60 mV/dek. Model SS analitikal feroelektrik NC FET yang digunakan bagi kajian ini adalah sesuai dengan SS yang diperoleh daripada hubungan antara arus serapan dan voltan get, menggunakan edaran potensi 2D. Dapatan terbitan melalui model SS analitikal, mendapati bahawa adalah mungkin bagi mendapatkan SS pada 60 mV/dek atau kurang walaupun panjang laluan adalah 15 nm dengan melaraskan ketebalan saluran silikon, SiO2, dan feroelektrik. Terutama apabila perubahan ketebalan feroelektrik SS adalah tepu ketika ketebalan SiO2 meningkat, dan hampir malar apabila ketebalan saluran silikon berkurang.

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Comparative Assessment of Numerical Techniques for Weibull Parameters’ Estimation and the Performance of Wind Energy Conversion Systems in Nigeria

The wind speed of a location is a critical parameter for analyzing wind energy conversion systems. Background knowledge has revealed that the two-parameter Weibull distribution is commonly used for fitting wind speed data because of its simplicity, flexibility and suitability. This research study examines wind speed data from five locations in Nigeria (Kano, Maiduguri, Jos, Abuja and Akure). It employs five numerical techniques, namely the maximum likelihood method, method of moment, power density method, empirical method and the logarithmic moment method, to estimate the Weibull parameters based on the locations’ data. The goodness of fit test is used to determine which numerical method best fits the distribution. The paper also considers the techno-economic design of wind electricity of five 25 kW pitch-controlled wind turbines with dissimilar characteristics. The test result presents the method of moment and empirical method as the best methods for calculating the Weibull parameters. Results also show that wind turbine-3 has the least cost of energy and wind turbine-5 has the highest cost of energy. ABSTRAK: Kelajuan angin sesuatu lokasi adalah parameter kritikal bagi menganalisa sistem penukaran tenaga angin. Latar belakang berkaitan telah mendedahkan 2-parameter taburan Weibull (Wbl) lazimnya digunakan bagi memadan data kelajuan angin berdasarkan kesederhanaan, fleksibiliti dan kesesuaian. Kajian penyelidikan ini adalah berkaitan ujian data kelajuan angin pada lima lokasi di Nigeria (Kano, Maiduguri, Jos, Abuja dan Akure). Ia menggunakan lima teknik berangka iaitu kaedah kemungkinan maksimum, kaedah momen, kaedah ketumpatan kuasa, kaedah empirikal dan kaedah momen logaritma bagi menganggar parameter Weibull berdasarkan lokasi data. Ujian kesesuaian digunakan bagi memastikan kaedah berangka adalah padanan paling sesuai bagi taburan. Kajian ini juga turut menimbang reka bentuk tekno-ekonomi elektrik angin bagi lima turbin angin 25 kW kawalan anggul dengan ciri berbeza. Dapatan kajian menunjukkan momen dan kaedah empirikal adalah kaedah terbaik bagi mengira parameter Weibull. Ini menunjukkan bahawa turbin angin-3 mempunyai kos tenaga paling rendah dan turbin angin-5 mempunyai kos tenaga tertinggi.

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Higher Derivative Block Method with Generalised Steplength for Solving First-Order Fuzzy Initial Value Problems

Block methods have been adopted in studies for solving first and higher order differential equations due to its impressive accuracy property. Taking a step further to improve this accuracy, researchers have considered the inclusion of higher-derivative terms in the block method, although this has been limited to the presence of one higher-derivative term in previous studies. Hence, this article aims at better accuracy by introducing two higher-derivative terms in the block method. In addition, this article presents a scheme with generalised step length such that there is flexibility on the choice of step length when developing the block method. The generalised step length scheme is adopted to develop a three-step block method for solving first-order fuzzy initial value problems. Its properties to ensure convergence and to show the region of absolute stability is investigated, and problems relating to charging and discharging of capacitor are considered. The absolute error shows the impressive accuracy of the three-step block method including obtaining the same values as the exact solution. Therefore, in addition to the new generalised algorithm presented in this article, a new three-step method for solving linear and nonlinear first order fuzzy initial value problems is presented. ABSTRAK: Kaedah blok digunakan dalam banyak kajian untuk menyelesaikan persamaan pembezaan peringkat pertama dan peringkat tinggi kerana sifat ketepatannya yang baik. Bagi meningkatkan ketepatan ini, penyelidik telah mengambil kira dengan memasukkan terbitan peringkat tinggi dalam kaedah blok, walaupun ini terhad pada satu sebutan terbitan peringkat tinggi dalam kajian sebelum. Oleh itu, kajian ini bertujuan bagi mendapatkan ketepatan yang lebih baik dengan memperkenalkan dua sebutan terbitan peringkat tinggi dalam kaedah blok. Tambahan, kajian ini memperkenalkan skema dengan panjang-langkah kaki biasa supaya terdapat kebolehlenturan pada pilihan langkah semasa membangunkan kaedah blok. Skema ini diadaptasi bagi membangunkan kaedah blok tiga-langkah bagi menyelesai masalah nilai awal peringkat pertama secara rawak. Ciri-ciri terperinci dikaji bagi memastikan penumpuan lingkungan kestabilan mutlak, dan masalah berkaitan pengecasan dan nyahcas kapasitor juga turut diambil kira. Ralat mutlak menunjukkan ketepatan yang mengkagumkan pada kaedah blok tiga-langkah termasuk mendapatkan nilai yang sama seperti penyelesaian. Oleh itu, tambahan pada algoritma ini, kaedah tiga-langkah bagi menyelesaikan linear dan tidak linear pada masalah nilai awal peringat pertama secara rawak diperkenalkan.

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