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MULTICRITERIA DECISION MAKING ON SUPPLIER SELECTION USING SOCCER MODEL INTEGRATED WITH ANALYTICAL HIERARCHY PROCESS
Get PDFSupplier evaluation and selection are key components in the supply chain because supplier performance directly affects the supply chain's efficiency. Therefore, companies should think strategically when they need to select their suppliers. Thus, selecting and evaluating new suppliers is essential in shaping the supply chain's smoothness and efficiency. Selecting suppliers is a complex issue as it involves many factors and decisions to be considered and needs to be assessed with an auditing process. However, a supplier audit is an expensive way to evaluate supplier capability. This research aims to propose a supplier selection model for a corrugated carton manufacturing company. The SOCCER model, developed by Steve Rogers, was used as the supplier selection criteria. Analytical Hierarchy Process (AHP) was used in the supplier selection. A face-to-face interview method was used in collecting data. The results show that the cost structure is the ultimate concern on supplier selection which bears 44.2% of the SOCCER model, followed by operational capability (23%), customer approach (13.5%), economic performance (8.3%), strategic direction (6.9%), and lastly research and development (4.1%). The percentages inform the company how much attention they need to pay when evaluating and selecting a new supplier.
ABSTRAK: Penilaian dan pemilihan pembekal adalah kunci utama dalam rantaian bekalan kerana prestasi pembekal secara langsung melibatkan kecekapan rantaian bekalan. Oleh itu, syarikat perlu memikirkan secara strategik apabila ingin memilih pembekal. Dengan demikian, pemilihan dan penilaian pembekal baru adalah penting dalam pembentukan kelancaran rantaian bekalan dan kecekapan. Pemilihan pembekal adalah isu kompleks kerana ianya melibatkan banyak faktor dan keputusan perlu difikirkan dan perlu dinilai bersama proses audit. Namun, audit pembekal adalah mahal bagi menilai kemampuan pembekal. Kajian ini mencadangkan model pemilihan pembekal bagi syarikat pembekal kotak karton. Model SOCCER dicipta oleh Steve Rogers, telah digunakan sebagai kritia pemilihan pembekal. Proses Hirarki Analitikal (AHP) digunakan dalam pemilihan pembekal. Kaedah temuduga bersemuka digunakan dalam pengumpulan data. Dapatan kajian menunjukkan struktur harga adalah kehendak utama dalam pemilihan pembekal iaitu 44.2% daripada model SOCCER, diikuti kemampuan operasi (23%), pendekatan pelanggan (13.5%), prestasi ekonomi (8.3%), misi strategik (6.9 %), dan akhirnya penyelidikan dan pembangunan (4.1%). Peratusan ini berguna untuk syarikat dalam memberi keutamaan dalam penilaian dan pemilihan pembekal baru.
ABSTRAK: Supplier evaluation and selection are key components in the supply chain because supplier performance directly affects the supply chain's efficiency. Therefore, companies should think strategically when they need to select their suppliers. Thus, selecting and evaluating new suppliers is essential in shaping the supply chain's smoothness and efficiency. Selecting suppliers is a complex issue as it involves many factors and decisions to be considered and needs to be assessed with an auditing process. However, a supplier audit is an expensive way to evaluate supplier capability. This research aims to propose a supplier selection model for a corrugated carton manufacturing company. The SOCCER model, developed by Steve Rogers, was used as the supplier selection criteria. Analytical Hierarchy Process (AHP) was used in the supplier selection. A face-to-face interview method was used in collecting data. The results show that the cost structure is the ultimate concern on supplier selection which bears 44.2% of the SOCCER model, followed by operational capability (23%), customer approach (13.5%), economic performance (8.3%), strategic direction (6.9 %), and finally research and development (4.1%). The percentages inform the company how much attention they need to pay when evaluating and selecting a new supplier
EMG BASED CONTROL OF WRIST EXOSKELETON
Get PDFThe significance of human motion intentions in a designed exoskeleton wrist control hand is essential for stroke survivors, thus making EMG signals an integral part of the overall system is critically important. However, EMG is a nonlinear signal that is easily influenced by several errors from its surroundings and certain of its applications require close monitoring to provide decent outcomes. Hence, this paper proposes to establish the relationship between EMG signals and wrist joint angle to estimate the desired wrist velocity. Fuzzy logic has been selected to form a dynamic modelling of wrist movement for a single muscle at different MVC levels and double muscles at a similar MVC level. The physical model of the exoskeleton hand using Simmechanics Matlab software has been developed to validate the performance of the fuzzy logic output result from both dynamic modelling approaches. A PID controller has been developed to smooth the exoskeleton hand movement fluctuations caused by the fuzzy logic decision-making process. As a conclusion, results showed a strong relationship between EMG signals and wrist joint angle improved the estimation results of desired wrist velocity for both dynamic modelling approaches hence strengthened the prediction process by providing a myoelectronic control device for the exoskeleton hand.
ABSTRAK: Kepentingan dalam mengetahui kehendak gerakan pergelangan tangan manusia adalah penting untuk pesakit strok yang terselamat, justeru menjadikan isyarat EMG amat penting pada keseluruhan sistem. Walau bagaimanapun, EMG adalah isyarat tidak linear yang mudah dipengaruhi ralat sekitaran dan memerlukan pemantauan rapi bagi hasil yang baik. Oleh itu, kajian ini mencadangkan kewujudan hubungan antara isyarat EMG dan sudut sendi pergelangan tangan bagi menganggarkan halaju pergelangan tangan yang dikehendaki. Logik kabur (fuzzy logic) telah dipilih bagi membentuk model dinamik pergerakan pergelangan tangan pada otot tunggal di tahap MVC yang berbeza dan otot berganda pada tahap MVC yang serupa. Model fizikal rangka luar tangan menggunakan perisian Matlab Simmekanik telah dibangunkan bagi mengesahkan prestasi Logik Kabur daripada kedua-dua pendekatan model dinamik. Pengawal PID telah dibangunkan bagi melicinkan gerakan turun naik tangan yang disebabkan proses membuat keputusan oleh Logik Kabur. Sebagai kesimpulan, dapatan kajian menunjukkan hubungan yang kukuh antara isyarat EMG dan sudut sendi pergelangan tangan. Ini meningkatkan anggaran dapatan halaju pergelangan tangan yang dikehendaki bagi kedua-dua pendekatan model dinamik seterusnya mengukuhkan proses ramalan melalui peranti kawalan mioelektronik rangka tangan
An Integrated RRT*SMART-A* Algorithm for solving the Global Path Planning Problem in a Static Environment
Get PDFThe use of sampling-based algorithms such as Rapidly-Exploring Random Tree Star (RRT*) has been widely applied in robot path planning. Although this variant of RRT offers asymptotic optimality, its use is increasingly limited because it suffers from convergence rates, mainly when applied to an environment with a poor level of obstacle neatness and a narrow area to the target. Thus, RRT*-Smart, a further development of RRT*, is considered ideal for solving RRT* problems. Unlike RRT*, RRT*-Smart applies a path optimization by removing the redundant nodes from the initial path when it is gained. Moreover, the path is also improved by identifying the beacon nodes used to steer the bias of intelligent sampling. Nevertheless, this initial path is found with termination criteria in terms of a region around the goal node. Consequently, it risks failing to generate a path on a narrow channel. Therefore, a novel algorithm achieved by combining RRT*-Smart and A* is proposed. This combination is intended to switch method-by-method for the exploration process when the new node reaches the region around the goal node. However, before RRT*-Smart is combined with A*, it is improved by replacing the random sampling method with Fast Sampling. In short, by involving A*, the exploration process for generating the Smart-RRT*’s initial path can be supported. It gives the optimal and feasible raw solution for any complex environment. It is logically realistic because A* searches and evaluates all neighbors of a current node when finding the node with low cost to the start and goal node for each iteration. Therefore, the risk of collision with an obstacle in the goal region is covered, and generating an initial path in the narrow channel can be handled. Furthermore, this proposed method's optimality and fast convergence rate are satisfied.
ABSTRAK: Penggunaan algoritma berasaskan pensampelan seperti Rapidly-Exploring Random Tree Star (RRT*) telah digunakan secara meluas dalam perancangan laluan robot. Walaupun varian RRT ini menawarkan keoptimuman tanpa gejala, penggunaannya semakin terhad kerana ia mengalami kadar penumpuan, terutamanya apabila digunakan pada persekitaran dengan tahap kekemasan halangan yang lemah dan kawasan yang sempit ke sasaran. Oleh itu, RRT*-Smart, pembangunan lanjut RRT*, dianggap sesuai untuk menyelesaikan masalah RRT*. Tidak seperti RRT*, RRT*-Smart menggunakan pengoptimuman laluan dengan mengalih keluar nod berlebihan daripada laluan awal apabila ia diperoleh. Selain itu, laluan juga dipertingkatkan dengan mengenal pasti nod suar yang digunakan untuk mengemudi bias pensampelan pintar. Namun begitu, laluan awal ini ditemui dengan kriteria penamatan dari segi rantau di sekeliling nod matlamat. Akibatnya, ia berisiko gagal menjana laluan pada saluran yang sempit. Oleh itu, algoritma baru yang dicapai dengan menggabungkan RRT*-Smart dan A* dicadangkan. Gabungan ini bertujuan untuk menukar kaedah demi kaedah untuk proses penerokaan apabila nod baharu sampai ke kawasan sekitar nod matlamat. Walau bagaimanapun, sebelum RRT*-Smart digabungkan dengan A*, ia diperbaiki dengan menggantikan kaedah persampelan rawak dengan Persampelan Pantas. Pendek kata, dengan melibatkan A*, proses penerokaan dalam menjana laluan awal yang Smart-RRT lakukan* boleh disokong. Ia memberikan penyelesaian mentah yang optimum dan boleh dilaksanakan untuk mana-mana persekitaran yang kompleks. Ia adalah realistik secara logik kerana A* mencari dan menilai semua jiran nod semasa apabila mencari nod dengan kos rendah ke nod permulaan dan matlamat untuk setiap lelaran. Oleh itu, risiko perlanggaran dengan halangan di kawasan matlamat dilindungi, dan menjana laluan awal dalam saluran sempit boleh dikendalikan. Tambahan pula, kaedah optimum yang dicadangkan dan kadar penumpuan yang cepat ini berpuas hati
APPLICATION OF DRIVING BEHAVIOR CONTROL SYSTEM USING ARTIFICIAL NEURAL NETWORK TO IMPROVE DRIVING COMFORT BY ADJUSTING AIR-TO-FUEL RATIO
Get PDFEnergy-efficient engines were introduced due to limited amount of global energy and the need for engine power to carry vehicle loads. It was discovered that the power factor of these engines was essential in developing automotive technology with subsequent significant effect on driving comfort. Moreover, it was possible to control the power and energy savings of vehicle engines by adjusting the Air to Fuel Ratio (AFR). Therefore, this study focused on achieving AFR values in the stoichiometric range of 14.7 in order to produce good emissions. The technology applied was observed to have some drawbacks, specifically in fulfilling engine power when the vehicle operates with a large load. This led to the development of a new method by designing an AFR control system with due consideration for driving behavior using an Artificial Neural Network (ANN). The aim was to overcome the problem of meeting engine power and ensuring better efficiency. The driving behavior was classified into through categories including the sporty, standard, and eco schemes. The eco scheme was the smooth behavior of a driver during the movement of the vehicle in a busy urban area, the sporty scheme was the responsive driving behavior when the vehicle operates on the highway at speeds above 80 km/h, and the standard scheme was the behavior between the eco and sporty schemes. Furthermore, the driving behavior in a sporty scheme required the addition of fuel to increase engine power while eco-scheme focused on reducing fuel to increase fuel economy. The findings showed that control system designed was able to improve driving comfort in terms of fuel economy during the eco scheme with an average AFR value of 15.68. The system further reduced the value to 13.66 during the sporty scheme. Furthermore, the AFR under stoichiometry was discovered to have produced the maximum engine power. The system was expected to be incorporated into electric, gas-fired and fuel cell vehicles in the future.
ABSTRAK: Faktor kuasa enjin dan enjin cekap tenaga adalah penting dalam membangunkan teknologi automotif. Mesin penjimat tenaga diperlukan kerana jumlah tenaga global yang terhad. Manakala kuasa enjin digunakan bagi membawa muatan kenderaan. Kedua-dua faktor ini sangat mempengaruhi keselesaan pemanduan. Penjimatan kuasa dan tenaga dalam enjin kenderaan boleh dipenuhi dengan mengawal Nisbah Angin kepada Minyak (AFR). Tumpuan kajian semasa adalah berorientasikan ke arah mencapai nilai AFR dalam julat stoikiometri (14.7) atas sebab ingin mencapai pelepasan terbaik. Namun begitu, teknologi ini mempunyai kelemahan terutama dalam memenuhi kuasa enjin apabila kenderaan beroperasi dengan muatan besar. Oleh itu, kajian ini adalah berkaitan kaedah baharu bagi mengatasi masalah memenuhi kuasa enjin dan mencapai enjin cekap tenaga dengan mereka bentuk sistem kawalan AFR yang mempertimbangkan tingkah laku pemanduan menggunakan Rangkaian Neural Buatan (ANN). Tingkah laku pemanduan direka bentuk kepada tiga skim: sporty, standard dan eko. Skim eko adalah kelancaran tingkah laku pemandu apabila kenderaan bergerak di kawasan bandar yang sibuk. Skim sporty ialah tingkah laku pemanduan responsif apabila kenderaan beroperasi di lebuh raya pada kelajuan melebihi 80 km/j, dan skema standard ialah tingkah laku antara skim eko dan sporty. Tingkah laku pemanduan dalam skema sporty memerlukan penambahan bahan api bagi meningkatkan kuasa enjin. Sementara itu, tingkah laku pemanduan dalam skim eko memerlukan pengurangan bahan api bagi meningkatkan penjimatan bahan api. Hasil kajian menyatakan sistem kawalan yang direka mampu meningkatkan keselesaan pemanduan dari segi penjimatan bahan api apabila tingkah laku pemandu memasuki skim eko. AFR dicapai pada nilai purata 15.68. Apabila tingkah laku pemandu memasuki skim pemanduan sporty, sistem kawalan boleh mengurangkan AFR dengan nilai purata 13.66. AFR di bawah stoikiometri menghasilkan kuasa enjin maksimum. Pada masa hadapan, sistem ini berpotensi untuk dibangunkan pada kenderaan elektrik, menggunakan gas dan sel bahan api
Editorial
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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, 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) 6421-629
A Hybrid of Kansei Engineering (KE) And Analytical Hierarchy Process (AHP) to Develop Conceptual Designs of Portable Oil Spill Skimmer
Get PDFCurrently, 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
EFFECTS OF HIVE SIZES AND MESH MATERIALS ON THE PRODUCTIVITY OF PROPOLIS PRODUCED BY TETRAGONULA LAEVICEPS
No full textPropolis and honey are bioproducts produced by Tetragonula laeviceps, a stingless bee species. Both products have anti-inflammatory, antimicrobial, and antibacterial properties. Modular Tetragonula hives of different sizes were used in the cultivation of T. laeviceps to increase the productivity of propolis while maintaining the sustainability of the bee colonies. This study was carried out in Jatinangor, West Java, Indonesia, with three size variations: small (21 × 18 × 14 cm), medium (26 × 22 ×17 cm), and large (30 × 26 × 17 cm). Each hive was equipped with a mesh of a different material. The results obtained in this study showed that increasing the hive’s size increases the productivity of propolis. The highest productivity of propolis (2.53 ± 0.37 g/colony/week) was obtained when T. laeviceps was cultivated in large hives equipped with a nylon-based mesh. The highest productivity of honey (0.78 ± 0.18 g/colony/week) was obtained when T. laeviceps was cultivated in medium hives equipped with an aluminum-based mesh. The harvested propolis was extracted using a maceration method. Total flavonoid and phenolic content of the propolis solution lies in the range of 1.77 ± 0.86 to 3.18 ± 1.43 mg QE/g propolis and 32.23 ± 14.09 to 112.13 ± 47.64 mg GAE/g propolis, respectively. The harvested honey had a water content of 21.86%, with 72.86% reducing sugar, 192.86 ?g/mL vitamin C, and 2613.41 ?g/mL of antioxidant content.
ABSTRAK: Propolis dan madu adalah produk bio yang dihasilkan oleh Tetragonula laeviceps, spesies lebah kelulut. Kedua-dua produk mempunyai ciri anti-radang, anti-mikrob dan antibakteria. Sarang Tetragonula modular dengan saiz yang berbeza digunakan dalam mengusahakan T. laeviceps bagi meningkatkan produktiviti propolis sambil mengekalkan kemampanan koloni lebah. Kajian ini dijalankan di Jatinangor, Jawa Barat, Indonesia, dengan tiga variasi saiz: kecil (21×18×14 cm), sederhana (26×22×17 cm), dan besar (30×26×17 cm). Setiap sarang dilengkapi dengan jaringan bahan yang berbeza. Dapatan kajian yang diperolehi melalui kajian ini menunjukkan bahawa penambahan saiz sarang dapat meningkatkan produktiviti propolis. Produktiviti tertinggi propolis (2.53±0.37 g/koloni/minggu) diperoleh apabila T. laeviceps dibela dalam sarang besar yang dilengkapi dengan jaring berasaskan nilon. Produktiviti madu tertinggi (0.78±0.18 g/koloni/minggu) diperoleh apabila T. laeviceps diusahakan dalam sarang sederhana yang dilengkapi dengan jaring berasaskan aluminium. Propolis yang dituai telah diekstrak menggunakan kaedah maserasi. Jumlah kandungan flavonoid dan kandungan fenolik larutan propolis berada dalam julat 1.77 ± 0.86 hingga 3.18 ± 1.43 mg QE/g propolis dan 32.23 ± 14.09 hingga 112.13 ± 47.64 mg GAE/g propolis, masing-masing. Madu yang dituai mempunyai kandungan air 21.86%, dengan 72.86% penurunan gula, 192.86 ?g/mL vitamin C, dan 2613.41 ?g/mL kandungan antioksidan
NON-NEWTONIAN VISCOSITY BEHAVIOUR INVESTIGATION FOR MALAYSIAN WAXY CRUDE OILS AND IMPACT TO WAX DEPOSITION MODELLING
Get PDFWax deposition is one of the major risks that causes a serious threat to pipeline transportation during operation, if not prevented. The remediation actions are usually costly; hence mitigation methods are in place to completely avoid the issues from happening. The wax deposition modelling technique has been accepted as a tool to design and continuously optimize the wax management strategy. Non-Newtonian oil-wax viscosity is an important parameter affecting wax deposition in pipelines. The present and widely used viscosity model assumes exponential behaviour as observed in the emulsion system. In this paper, it is demonstrated that this assumption may not be suitable for Malaysian waxy crude oil applications due to instantaneous change of viscosity below WAT and PPT. This paper focuses on the application of the Pedersen and Ronningsen viscosity model available in the commercial fluid and flow simulators namely PVTsim ®, Multiflash ® and OLGA ® which are widely used by the flow assurance fraternities, and how it will impact wax deposition prediction accuracy specifically when applied to Malaysian waxy crude oils.
ABSTRAK: Pemendapan lilin adalah salah satu risiko utama yang menyebabkan ancaman serius kepada pengangkutan saluran paip semasa operasi jika tidak dicegah. Proses membaiki biasanya memerlukan kos yang tinggi; oleh itu kaedah mitigasi disediakan bagi mengelakkan isu ini daripada berlaku. Teknik model pemendapan lilin telah diterima sebagai alat bagi mereka bentuk dan merupakan strategi optimum pengurusan lilin secara berterusan. Kelikatan minyak-lilin bukan Newton adalah salah satu parameter penting yang mempengaruhi pemendapan lilin dalam saluran paip. Anggaran model kelikatan semasa yang digunakan secara meluas menjangkakan tingkah laku eksponen seperti yang diperhatikan dalam sistem emulsi. Kajian ini menunjukkan bahawa kaedah anggaran mungkin tidak sesuai bagi aplikasi minyak mentah berlilin Malaysia disebabkan oleh perubahan kelikatan serta-merta di bawah WAT dan PPT. Kertas kerja ini memberi tumpuan kepada aplikasi model kelikatan Pedersen dan Ronningsen yang terdapat dalam cecair komersial dan simulator aliran iaitu PVTsim ®, Multiflash ® dan OLGA ® yang digunakan secara meluas oleh persatuan jaminan aliran, dan keberkesanan pada ketepatan anggaran pemendapan lilin khususnya apabila digunakan pada minyak mentah berlilin Malaysia
SYSTEM IDENTIFICATION (SI) MODELLING, CONTROLLER DESIGN AND HARDWARE TESTING FOR VERTICAL TRAJECTORY OF UNDERWATER REMOTELY OPERATED VEHICLE (ROV)
Get PDFUnderwater remotely operated vehicles (ROV) are important in marine industries to accomplish underwater exploration and surveying. The underwater environment makes it hard for ROV operators to control the manipulator while holding position simultaneously. This led to modelling and controller design for the vertical trajectory of ROV. In this paper, the System Identification (SI) modeling technique was used to model the vertical trajectory of the ROV. Then, the Proportional, Integral, and Derivative (PID) controller was implemented to control the trajectory. The SI modelling technique was used as it estimates the model based on the input and output relationship. MATLAB SI toolbox was used as the analytical software. Step and multiple step inputs were given to the system and the responses were recorded. The model with the best fit of 84.7% was selected and verified by comparing with actual output. The model response was then analyzed and the PID controller was implemented. The actual model had high percent overshoot (%OS) and steady state error (SSE). The PID implementation successfully reduced the %OS and eliminated the SSE.
ABSTRAK: Kenderaan bawah air kendalian jauh (ROV) adalah penting dalam industri marin bagi melaksanakan penerokaan dan pemerhatian bawah air. Persekitaran dalam air menyukarkan pengendali ROV bagi memanipulasi manipulator sambil memastikan kedudukan ROV secara serentak. Ini membawa kepada pemodelan dan mereka bentuk kawalan pergerakan menegak bagi ROV. Kajian ini menggunakan teknik pemodelan Sistem Pengenalan (SI) bagi memodelkan pergerakan menegak ROV. Kemudian, kawalan seimbang, menyeluruh dan terbitan (PID) dilaksanakan bagi mengawal trajektori. Teknik pemodelan SI digunakan kerana ia menganggarkan model berdasarkan kemasukan dan keluaran. Aplikasi MATLAB SI digunakan sebagai perisian analisis. Masukan satu langkah dan berbilang kali masukan telah dijalankan dan respons sistem direkodkan. Model yang paling sesuai mencapai 84.7% dipilih dan disahkan dengan perbandingan nilai keluaran sebenar. Respons model kemudiannya dianalisis dan kawalan PID dilaksanakan. Model sebenar mempunyai peratusan tinggi melampaui (%OS) dan ralat keadaan stabil (SSE). Pelaksanaan PID telah berjaya mengurangkan %OS dan menghapuskan SSE
EFFECT OF PRINTING PARAMETERS AND POST-CURING ON MECHANICAL PROPERTIES OF PHOTOPOLYMER PARTS FABRICATED VIA 3D STEREOLITHOGRAPHY PRINTING
Get PDFThree-dimensional printing has recently come into the spotlight due to its promising potential to create physically three-dimensional parts or structures through computer-aided design. While there are many options for 3D printing methods, photopolymerization 3D printing has garnered much attention because of its high resolution. However, the mechanical properties of photopolymerized 3D printed parts can vary widely depending on the manufacturing parameters and post-processing settings used. This research focuses on studying the effect of printing variables on the mechanical properties of samples printed using a Stereolithography machine (Formlabs, Form+3). Three variables are used: layer thickness (25 and 50 ?m), part orientation (X and Z directions), and post-curing. Also, eight groups of 3D-printed photopolymer specimens for twenty-four specimens are used for the tensile test results. The results showed the printing variables affected the mechanical properties of samples, which were proven by Young's modulus, ultimate stress, and ultimate strain.
ABSTRAK: Pencetakan tiga dimensi baru-baru ini menjadi perhatian kerana potensinya yang menjanjikan bagi mencipta bahagian atau struktur tiga dimensi secara fizikal melalui reka bentuk bantuan komputer. Walaupun terdapat banyak pilihan bagi kaedah percetakan 3D, pencetakan 3D fotopolimerisasi telah mendapat banyak perhatian kerana resolusinya yang tinggi. Walau bagaimanapun, sifat mekanikal bahagian bercetak 3D fotopolimer adalah pelbagai bergantung pada parameter pembuatan dan tetapan pasca pemprosesan yang digunakan. Kajian ini memberi tumpuan kepada kesan pembolehubah cetakan terhadap sifat mekanikal sampel yang dicetak menggunakan mesin Stereolitografi (Formlabs, Form+3). Tiga pembolehubah digunakan: ketebalan lapisan (25 dan 50 ?m), orientasi bahagian (arah X dan Z), dan pasca pengawetan. Juga, lapan kumpulan spesimen fotopolimer cetakan 3D untuk dua puluh empat spesimen digunakan bagi mendapatkan keputusan ujian tegangan. Dapatan kajian menunjukkan pembolehubah cetakan mempengaruhi sifat mekanikal sampel, dibuktikan oleh modulus Young, tegangan utama, dan tarikan utama