https://journals.iium.edu.my/ejournal/index.php/iiumej/issue/feed IIUM Engineering Journal 2023-01-04T13:57:51+08:00 Prof. Dr. AHM Zahirul Alam zahirulalam@iium.edu.my Open Journal Systems <div style="text-align: justify;"> <p>The IIUM Engineering Journal, published biannually (<strong>January </strong><em>and </em><strong>July</strong>), is a <em><strong>double-blind peer-reviewed</strong></em> open-access journal of the Kulliyah of Engineering, International Islamic University Malaysia (IIUM).</p> <p><strong>January 2022</strong> issue is already in the <strong>Scopus</strong> database. <strong><a title="IIUMEJ Scopus" href="https://www.scopus.com/results/results.uri?sort=cp-f&amp;src=s&amp;st1=IIUM+Engineering+Journal&amp;nlo=&amp;nlr=&amp;nls=&amp;sid=a0be40258badf5dd35fc1e6a466b12cb&amp;sot=b&amp;sdt=cl&amp;cluster=scopubyr%2c%222022%22%2ct&amp;sl=34&amp;s=SRCTITLE%28IIUM+Engineering+Journal%29&amp;origin=resultslist&amp;zone=leftSideBar&amp;editSaveSearch=&amp;txGid=26402634b7147d3471bd39459a80962b" target="_blank" rel="noopener">Click here</a> </strong></p> <div style="border: 2px solid #C0C0C0; padding: 3px;"><span style="color: #ff0000;"><em><strong> </strong></em></span></div> <div style="border: 2px solid #C0C0C0; padding: 3px;"><span style="color: #ff0000;"><em><strong>Recently we have received many emails to verify the acceptance letter. It is the author's responsibility to check the authenticity if the author did not submit any article through this site and email transmits from the iium.edu.my domain. </strong></em></span></div> <p>The IIUM Engineering Journal publishes original research findings as regular papers, review papers (by invitation). The Journal provides a platform for Engineers, Researchers, Academicians, and Practitioners who are highly motivated in contributing to the Engineering disciplines and Applied Sciences. It also welcomes contributions that address solutions to the developing world's specific challenges and address science and technology issues from an Islamic and multidisciplinary perspective.<strong> </strong></p> <p><strong>Subject areas suitable for publication are as follows:</strong> </p> <ul> <li class="show">Chemical and Biotechnology Engineering</li> <li class="show">Civil and Environmental Engineering</li> <li class="show">Computer Science and Information Technology</li> <li class="show">Electrical, Computer, and Communications Engineering</li> <li class="show">Engineering Mathematics and Applied Science</li> <li class="show">Materials and Manufacturing Engineering</li> <li class="show">Mechanical and Aerospace Engineering</li> <li class="show">Mechatronics and Automation Engineering</li> </ul> <p>Contributions from other areas of Engineering and Applied Science are welcome.</p> <p>A manuscript undergoes a double-blind review process. </p> <p><strong><strong>IIUM Engineering Journal Publication Ethics and Malpractice Statements</strong>:</strong></p> <p>IIUMEJ is committed to meeting and upholding standards of ethical behaviour at all stages of the publication process. A summary of our expectations of editors, peer-reviewers, and authors is stated here [<a title="Editorial Policies" href="https://journals.iium.edu.my/ejournal/index.php/iiumej/ethics">link</a>].</p> </div> https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2382 A Quick and Facile Solution-Processed Method for PEDOT:PSS Transparent Conductive Thin Film 2023-01-04T00:23:46+08:00 Mei Bao Lee mblee2@graduate.utm.my Chiew Tin Lee ctlee5@graduate.utm.my William Woei Fong Chong william@utm.my Suhaila Mohd Sanip s.m.sanip@soton.ac.uk <p>PEDOT:PSS is a conducting organic polymer widely studied for a transparent conductive electrode. The conventional method to fabricate PEDOT:PSS thin film involves a post-treatment process entailing dipping into strong and toxic saturated acid to enhance the film’s conductivity. Eliminating the post-treatment process reduces excess strong saturated acid or solvent waste, shortening the fabricating time by half. Therefore, this study presents a quick and facile solution-processed method for fabricating the PEDOT:PSS transparent conductive thin film (without a post-treatment process) while still achieving the requirements for a transparent conductive electrode (TCE). A parametric study was conducted by adding 5 wt% to 80 wt% of benzene sulfonic acid (BA) to PEDOT:PSS during the formulation stage before being dried at elevated temperatures from 80 °C to 200 °C. The optimum sheet resistance and transmittance value could be achieved for a thin film fabricated from PEDOT:PSS added with 40 wt% of BA, and dried at 120 °C. The sheet resistance and transmittance values are 80 ?/sq and 93.6%, respectively. The generated figure of merit (FOM) value is 70.1, indicating an improvement of almost five times compared to the FOM value of 14.6 generated using the conventional method, requiring a post-treatment process.</p> <p><strong><em>ABSTRAK:</em></strong> PEDOT:PSS adalah bahan polimer organik yang mengkonduksi arus dan dikaji secara meluas bagi digunakan sebagai elektrod konduktif telus. Kaedah konvensional untuk menghasilkan filem nipis PEDOT:PSS melibatkan proses pasca rawatan iaitu dengan mencelupkan filem nipis PEDOT:PSS ke dalam asid pekat bertoksik bagi meningkatkan konduksi filem tersebut. Tanpa proses pasca rawatan ini dapat mengurangkan penghasilan sisa lebihan seperti asid pekat bertoksik atau pelarut buangan, memendekkan masa fabrikasi sebanyak separuh. Oleh itu, kajian ini menghasilkan kaedah proses-penyelesaian yang cepat dan mudah bagi fabrikasi filem nipis PEDOT:PSS (tanpa proses pasca rawatan) disamping masih mencapai keperluan sebagai elektrod konduktif telus (TCE). Kajian parametrik telah dijalankan dengan menambah 5 wt% hingga 80 wt% asid sulfonik benzena (BA) ke dalam PEDOT:PSS pada peringkat percampuran kimia sebelum dikeringkan pada kenaikan suhu secara berperingkat dari 80 °C sehingga 200 °C. Nilai optimum bagi rintangan lapisan dan nilai ketelusan bagi filem nipis PEDOT:PSS yang difabrikasi dapat dicapai melalui penambahan sebanyak 40 wt% BA dan dikeringkan pada suhu 120 °C. Rintangan lapisan dan nilai ketelusan telah dicapai sebanyak 80 ?/sq dan 93.6%, masing-masing. Nilai gambaran merit (FOM) yang terhasil adalah 70.1, menunjukkan peningkatan hampir lima kali ganda berbanding nilai FOM 14.6 yang terhasil menggunakan kaedah konvensional yang memerlukan proses pasca-rawatan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2426 A Hybrid of Kansei Engineering (KE) And Analytical Hierarchy Process (AHP) to Develop Conceptual Designs of Portable Oil Spill Skimmer 2023-01-04T00:23:38+08:00 Rprakash Ramanathan m052010032@student.utem.edu.my Lokman Abdullah lokman@utem.edu.my Muhammad Hafidz Fazli Md Fauadi hafidz@utem.edu.my Muhammad Syafiq Syed Mohamed syafiq@utem.edu.my Khairun Najmi Kamaludin p052010004@student.utem.edu.my <p>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.</p> <p><strong><em>ABSTRAK:</em></strong> 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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/1629 Solid State Fermentation of Turmeric Rhizomes with Aspergillus SP. To Improve Yield and Composition of Extracted Turmeric Oil 2023-01-04T00:24:40+08:00 Muhammad Yusuf Abduh yusuf@sith.itb.ac.id Asri Ifani Ramawati asriifani1996@gmail.com Tinta Komariyah tintakomariyah@gmail.com Yohanes Theda yohanestheda@gmail.com <p>This research aimed to determine the role of <em>Aspergillus awamori</em>, <em>Aspergillus niger</em>, and <em>Aspergillus oryzae</em> in degrading starch on turmeric rhizome substrate to increase the yield of turmeric oil. The substrate in the form of turmeric rhizome was given additional yeast extract of 10% weight per volume to meet the nutritional needs of fungal growth. The fungal concentration used in inoculation was 5x10<sup>7</sup> cells/ml. The solid-state fermentation process was carried out in dark conditions (~0 W), temperatures of 25–28 ºC, 99% humidity, and aeration (3.5 L/min). Turmeric oil was isolated using a steam distillation method for three hours, with the substrate moisture content of 68–71% and a substrate–water ratio of 1:5. The biodegradation process was conducted for 11 days. The starch content and turmeric oil yield was determined during the fermentation particularly on days 7, 9, and 11. The results showed that the biodegradation process of starch in solid-state fermentation succeeded in increasing the yield of turmeric oil. <em>Aspergillus awamori</em> showed the most desirable starch degradation activity by 62.5% to 2.9% wet weight on the 11<sup>th</sup> day of fermentation. <em>Aspergillus oryzae</em> had the most positive effect, nearly doubling the turmeric oil yield to 3.17% dry weight after 11<sup>th </sup>day of fermentation. The main constituents of turmeric oil are ?-turmerone, ?-turmerone, and ar-turmerone.</p> <p><strong><em>ABSTRAK: </em></strong>Penelitian ini bertujuan bagi mengkaji peranan Aspergillus awamori, Aspergillus niger, dan Aspergillus oryzae dalam mendegradasikan kanji pada substrat rizom kunyit bagi meningkatkan hasil minyak kunyit. Substrat dalam bentuk rizom kunyit telah diberi tambahan ekstrak yis 10% mengikut berat setiap isipadu bagi memenuhi keperluan nutrisi pertumbuhan kulat. Kepekatan kulat yang digunakan dalam inokulasi adalah 5x107 sel/ml. Proses penapaian berkeadaan pepejal telah dijalankan dalam keadaan gelap (~0 W), suhu 25–28 ºC, kelembapan 99%, dan pengudaraan (3.5 L/min). Minyak kunyit diasingkan menggunakan kaedah penyulingan wap selama tiga jam, dengan kandungan lembapan substrat 68-71% dan nisbah substrat-air 1:5. Proses biodegradasi dijalankan selama 11 hari. Kandungan kanji dan hasil minyak kunyit ditentukan semasa penapaian terutamanya pada hari ke-7, 9, dan 11. Hasil kajian menunjukkan bahawa proses biodegradasi kanji dalam penapaian berkeadaan pepejal berjaya meningkatkan hasil minyak kunyit. Aspergillus awamori menunjukkan aktiviti degradasi kanji yang paling diingini iaitu sebanyak 62.5% hingga 2.9% berat basah pada hari ke-11 penapaian. Aspergillus oryzae mempunyai kesan yang paling positif, iaitu hampir dua kali ganda hasil minyak kunyit kepada 3.17% berat kering selepas hari ke-11 penapaian. Konstituen utama minyak kunyit ialah ?-turmerone, ?-turmerone, dan ar-turmerone.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2400 Effect of the lignocellulolytic substrates and fermentation process parameters on myco-coagulant production for water treatment 2023-01-04T00:23:42+08:00 Maroua Fellah f.maroua@live.iium.edu.my MD ZAHANGIR ALAM zahangir@iium.edu.my ABDULLAH AL-MAMUN mamun@iium.edu.my NASSERLDEEN AHMED KHABBASHI nasreldin@iium.edu.my NURUL SAKINAH ENGLIMAN sakinahengliman@iium.edu.my SONIA HADJ ARAB soniahadjarab88a@gmail.com <p>In the present research, a fungal strain was used to produce a myco-coagulant via solid-state bioconversion to reduce water turbidity. The production of myco-coagulant was achieved using several low-cost lignocellulolytic substrates, namely coco peat, sawdust, palm kernel cake, and rice bran as sources of carbon and nitrogen. This research involves the study of both the effect of lignocellulolytic substrates and the parameters involved in the fermentation process for myco-coagulant production. Coco peat was chosen as a suitable lignocellulolytic substrate to serve as a carbon source for producing myco-coagulant, potentially reducing the turbidity by 84.6% from the kaolin suspension. Sawdust, palm kernel cake, and rice bran showed 33.06%, 30.18, and 21.18 %, respectively. Furthermore, a statistical approach to the Plackett-Burman design was conducted to evaluate the significant parameters that affect the production of myco-coagulant. Eleven fermentation process parameters were selected: concentration of coco peat (2- 4 %), incubation time (5-9 days), temperature (25-35 °C), pH (5-9), glucose (0-2 %), malt extract (1-2 %), yeast extract (0-2%), wheat flour (0-2 %), ammonium sulfate (0-1 %), inoculum size (1-3 %) and potassium dihydrogen phosphate (0-0.5 %). The selected variables were assessed through statistical analysis (main effects) based on their significance. Based on the main effect of each variable on flocculation activity, three variables, namely glucose, malt extract, and pH influenced high levels. On the other hand, the remaining eight variables did not significantly affect the production of myco-coagulant. Furthermore, a deeper study was conducted to further optimize the three effective variables involved in the fermentation process to evaluate these factors' influence on flocculation activity.</p> <p><strong><em>ABSTRAK: </em></strong>Penyelidikan ini adalah berkenaan strain fungus yang digunakan bagi menghasilkan miko-koagulan melalui penukaran-bio berkeadaan pepejal bagi mengurangkan kekeruhan air. Miko-koagulan dihasilkan dengan menggunakan beberapa substrat lignoselulolitik berkos rendah, iaitu habuk kelapa, habuk papan, hampas kelapa sawit, dan dedak padi sebagai sumber karbon dan nitrogen. Penyelidikan ini mengkaji kesan substrat lignoselulolitik dan faktor-faktor yang terlibat dalam proses fermentasi bagi menghasilkan miko-koagulan. Habuk kelapa dipilih sebagai substrat lignoselulolitik yang sesuai berfungsi sebagai sumber karbon dalam menghasilkan miko-koagulan, berpotensi mengurangkan kekeruhan sebanyak 84.6% daripada ampaian kaolin. Sebaliknya, habuk papan, hampas kelapa sawit, dan dedak padi menunjukkan 33.06%, 30.18, dan 21.18 %, masing-masing. Tambahan pula, pendekatan statistik ke atas reka bentuk Plackett-Burman telah dijalankan bagi menilai parameter penting yang mempengaruhi penghasilan miko-koagulan. Sebelas parameter proses penapaian telah dipilih: kepekatan habuk kelapa (2- 4 %), masa pengeraman (5-9 hari), suhu (25-35 C), pH (5-9), glukosa (0-2 %), ekstrak malt (1-2), tepung gandum (0-2 %), ammonium sulfat (0-1%), saiz inokulum (1-3 %) dan Kalium dihidrogen fosfat (0-0.5 %). Pemboleh ubah yang dipilih dinilai melalui analisis statistik berdasarkan kepentingannya. Berdasarkan kesan utama setiap pemboleh ubah terhadap aktiviti penggumpalan, tiga pemboleh ubah ini adalah glukosa, ekstrak malt, dan pH yang memberi kesan tertinggi. Sebaliknya, lapan pemboleh ubah lain tidak mempengaruhi penghasilan miko-koagulan dengan ketara. Tambahan lagi, kajian yang lebih mendalam telah dijalankan bagi membaiki tiga pemboleh ubah utama yang terlibat dalam proses fermentasi bagi menilai kesan yang mempengaruhi aktiviti penggumpalan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2447 The Optimization of Growth Condition of the Bacteria Producing Cold-Active Proteolytic Enzyme from the Antarctic Region 2023-01-04T00:23:28+08:00 Muhammad Asyraf Abd Latip m.asyrafabdlatip@gmail.com Noor Faizul Hadry Nordin faizul@iium.edu.my Siti Aisyah Alias saa@um.edu.my Jerzy Smykla smykla@iop.krakow.pl Faridah Yusof yfaridah@iium.edu.my Mohd Azrul Naim Mohamad aznaim@iium.edu.my <p>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 10<sup>6</sup> cells/hr. Optimal growth conditions of SC8 from this study are useful for the large-scale production of cold-active protease in future.</p> <p><strong><em>ABSTRAK: </em></strong>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 10<sup>6</sup> sel/jam. Keadaan pertumbuhan optimum SC8 daripada kajian ini bermanfaat untuk menghasilkan produk protease aktif sejuk secara besar-besaran pada masa hadapan.</p> <p>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 10<sup>6</sup> cells/hr. Optimal growth conditions of SC8 from this study are useful for the large-scale production of cold-active protease in future.</p> <p><strong><em>ABSTRAK: </em></strong>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 10<sup>6</sup> sel/jam. Keadaan pertumbuhan optimum SC8 daripada kajian ini bermanfaat untuk menghasilkan produk protease aktif sejuk secara besar-besaran pada masa hadapan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2468 Rhodopseudomonas Palustris Collagen-Like Recombinant Protein Purification Using an Aqueous Two-Phase System 2022-10-20T11:10:46+08:00 Nursyahidatul Azwa Awang nursyahidatulazwa@gmail.com Azura Amid azuraamid@iium.edu.my Zatul Iffah Arshad zatul@ump.edu.my <p>The potential use of recombinant collagen-like protein (recCLP) extracted from bacteria as disease-free collagen has been studied over the past decade. However, the complexity of the downstream processing generates high demand for an efficient and low-cost purification method. Aqueous two-phase system (ATPS) was adopted as a new approach to the recovery of biomolecules due to its simple, benign, and straightforward process. This study aimed to purify recombinant collagen-like protein from <em>Rhodopseudomonas palustris</em> using ATPS formed by a polymer/salt system. Recombinant collagen-like protein from <em>R. palustris</em> was partitioned in ATPS composed of polyethylene glycol (PEG) and potassium phosphate and several factors that influence the protein partitioning such as volume ratio, system pH, the concentration of polymer and salt were studied. Then, optimization of the selected ATPS conditions (PEG and salt concentration) were performed using response surface methodology (RSM). Results showed that the optimum conditions were found in ATPS with 24.80% (w/w) PEG 2000 and 29.23% (w/w) potassium phosphate with recCLP concentration of 3.23 ± 0.12 mg/mL with purification factor 7.48 ± 0.3. In comparison with the affinity chromatography method, ATPS was found to be low-cost, and time-saving with a higher protein recovery. Hence, this study demonstrated the potential application of ATPS in the recovery of recombinant CLPs for large-scale downstream processing.</p> <p><strong><em>ABSTRAK: </em></strong>Potensi penggunaan protein seperti kolagen rekombinan (recCLP) yang diekstrak daripada bakteria sebagai kolagen bebas penyakit telah dikaji sejak sedekad yang lalu. Walau bagaimanapun, kerumitan pemprosesan hiliran menjana permintaan yang tinggi untuk kaedah penulenan yang cekap dan berpatutan. Sistem akueus dua fasa (ATPS) telah diterima pakai sebagai pendekatan baharu dalam pemulihan biomolekul kerana prosesnya yang mudah. Tujuan utama kajian ini adalah untuk menyaring protein seperti kolagen rekombinan daripada <em>Rhodopseudomonas palustris</em> menggunakan ATPS yang dibentuk oleh sistem polimer/garam. Protein seperti kolagen rekombinan daripada <em>R. palustris</em> telah dibahagikan dalam ATPS yang terdiri daripada polietilena glikol (PEG) dan kalium fosfat dan beberapa faktor yang mempengaruhi pembahagian protein seperti nisbah isipadu, pH sistem, kepekatan polimer dan garam telah dikaji. Kemudian, keadaan ATPS terpilih (PEG dan kepekatan garam) telah dioptimumkan menggunakan metodologi permukaan tindak balas (RSM). Keputusan menunjukkan bahawa keadaan optimum dalam ATPS adalah 24.80% (b/b) PEG 2000 dan 29.23 % (b/w) kalium fosfat dengan kepekatan recCLP 3.23 ± 0.12 mg/mL dengan faktor penulenan 7.48 ± 0.3. Berbanding dengan kaedah kromatografi afiniti, ATPS didapati menjimatkan kos dan masa dengan pemulihan protein yang lebih tinggi. Oleh itu, kajian ini menunjukkan potensi aplikasi ATPS dalam pemulihan CLP rekombinan untuk pemprosesan hiliran berskala besar.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2435 Battery Energy Storage System (BESS) Modeling for Microgrid 2023-01-04T00:23:33+08:00 Zahir Zulkifly zaherzulkifly@gmail.com Siti Hajar Yusoff sitiyusoff@iium.edu.my Nor Liza Tumeran norliza.tumeran@iium.edu.my Nur Syazana Izzati Razali syazanaizzati1234@gmail.com <p>In the age of technology, microgrids have become well known because of their capability to back up the grid when an unpleasant event is about to occur or during power disruptions, at any time. However, the microgrid will not function well during power disruptions if the controller does not respond fast enough and the BESS will be affected. Many types of controllers can be used for microgrid systems. The controllers may take the form of Maximum Power Point Tracking (MPPT) Controller, Proportional Integral Derivative (PID) Controller, and Model Predictive Controller (MPC). Each of the controllers stated has its functions for the microgrid. However, two controllers that must be considered are PID and MPC. Both controllers will be compared based on their efficiency results which can be obtained through simulations by observing both graphs in charging and discharging states. Most researchers implied that MPC is better than PID because of several factors such as MPC is more robust and stable because of its complexity. Other than that, MPC can handle more inputs and outputs than PID which can cater to one input and output only. Although MPC has many benefits over the PID, still it is not ideal due to its complex algorithm. This work proposed an algorithm of simulations for the MPC to operate to get the best output for microgrid and BESS and compare the performance of MPC with PID. Using Simulink and MATLAB as the main simulation software is a very ideal way to simulate the dynamic performance of MPC. Furthermore, with Simulink, unpredictable variables such as Renewable Energy (RE) sources input and loads demands that are related to MPC can be measured easily. The algorithm of MPC is a cost function. Then the performance of the MPC is calculated using Fast-Fourier Transform (FFT) and Total Harmonic Distortion (THD). Lower THD means a higher power factor, this results in higher efficiency. This paper recorded THD of 9.57% and 12.77% in charging states and 16.51% and 18.15% in discharging states of MPC. Besides, PID recorded THD of 22.10% and 29.73% in charging states and 84.29% and 85.58% in discharging states. All of the recorded THD is below 25% in MPC and it shows a good efficiency while PID’s THD is above 25% shows its inefficiency.</p> <p><strong><em>ABSTRAK: </em></strong>Pada zaman teknologi, mikrogrid menjadi terkenal kerana keupayaannya untuk menjana kuasa grid apabila kejadian yang tidak menyenangkan bakal berlaku atau ketika terjadinya gangguan kuasa, pada bila-bila masa. Walau bagaimanapun, mikrogrid tidak dapat berfungsi dengan baik semasa gangguan kuasa jika alat kawalan tidak bertindak balas dengan cukup pantas dan BESS akan terjejas. Banyak alat kawalan (pengawal) boleh digunakan bagi keseluruhan sistem mikrogrid. Setiap pengawal adalah berbeza seperti Pengawal Penjejakan Titik Kuasa Maksimum (MPPT), Pengawal Berkadar Terbitan Kamilan (PID) dan Pengawal Model Ramalan (MPC). Setiap pengawal yang dinyatakan mempunyai fungsinya yang tersendiri bagi mikrogrid. Walau bagaimanapun, dua pengawal yang perlu dipertimbangkan adalah PID dan MPC. Kedua-dua pengawal ini akan dibandingkan berdasarkan keputusan kecekapan yang boleh didapati melalui simulasi dengan memerhati kedua-dua graf pada keadaan pengecasan dan nyahcas. Ramai penyelidik menganggap bahawa MPC adalah lebih baik berbanding PID kerana beberapa faktor seperti MPC lebih teguh dan stabil kerana kerumitannya. Selain itu, MPC dapat mengendalikan lebih banyak input dan output berbanding PID yang hanya dapat menyediakan satu input dan output sahaja. Walaupun MPC mempunyai banyak faedah berbanding PID, ianya masih tidak sesuai kerana algoritma yang kompleks. Kajian ini mencadangkan algoritma simulasi bagi MPC beroperasi mendapatkan output terbaik untuk mikrogrid dan BESS dan membandingkan prestasi MPC dengan PID. Perisian simulasi utama yang sangat ideal bagi mensimulasi prestasi dinamik MPC adalah dengan menggunakan Simulink dan MATLAB. Tambahan, dengan Simulink, pembolehubah yang tidak terjangka seperti sumber Tenaga Boleh Diperbaharui (RE) dan permintaan beban yang berkaitan MPC boleh diukur dengan mudah. Algoritma MPC adalah satu fungsi kos. Kemudian prestasi MPC dikira menggunakan Penjelmaan Fourier Pantas (FFT) dan Total Pengherotan Harmonik (THD). THD yang lebih rendah bermakna faktor kuasa meningkat, ini menghasilkan kecekapan yang lebih tinggi. Kajian ini mencatatkan THD sebanyak 9.57% dan 12.77% dalam keadaan mengecas dan 16.51% dan 18.15% dalam keadaan nyahcas oleh MPC. Selain itu, PID mencatatkan THD sebanyak 22.10% dan 29.73% dalam keadaan mengecas dan 84.29% dan 85.58% dalam keadaan nyahcas. Semua THD yang direkodkan adalah di bawah 25% bagi MPC dan ia menunjukkan kecekapan yang baik manakala THD bagi PID adalah melebihi 25% menunjukkan ketidakcekapan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2508 Analytical Model of Subthreshold Swing for Junctionless Double Gate MOSFET Using Ferroelectric Negative Capacitance Effect 2023-01-04T00:21:58+08:00 Hakkee Jung hkjung@kunsan.ac.kr <p>An analytical Subthreshold Swing (SS) model is presented to observe the change in the SS when a stacked SiO<sub>2</sub>-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, SiO<sub>2</sub>, and ferroelectric. In particular, the change in SS according to the ferroelectric thickness was saturated as the thickness of SiO<sub>2</sub> increased and was almost constant as the thickness of the silicon channel decreased.</p> <p><strong><em>ABSTRAK: </em></strong>Model Ayunan Subambang (SS) analitikal dibentangkan bagi melihat perubahan pada SS apabila struktur feroelektrik-logam-SiO<sub>2</sub> 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, SiO<sub>2</sub>, dan feroelektrik. Terutama apabila perubahan ketebalan feroelektrik SS adalah tepu ketika ketebalan SiO<sub>2</sub> meningkat, dan hampir malar apabila ketebalan saluran silikon berkurang.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2597 Robust and Imperceptible Watermarking on Medical Images using Coefficient Pair Modification 2023-01-04T00:21:48+08:00 Ledya Novamizanti ledyaldn@telkomuniversity.ac.id Andriyan Bayu Suksmono suksmono@stei.itb.ac.id Donny Danudirdjo donny@stei.itb.ac.id Gelar Budiman gelarbudiman@telkomuniversity.ac.id <p>Sensitive data including medical images and electronic patient records (EPR) have potential value in the era of big data and telemedicine applications. Distribution of medical images and EPR over public networks requires a high level of privacy and security. Robust and imperceptible watermarking techniques are needed to provide copyright preservation for medical images and protect patient information security. This paper improves the technique of Coltuc et al. by modifying the discrete cosine transform (DCT) coefficient pairs in the watermark embedding formula. Our proposed formula ensures that the difference between the two coefficients is at least ????. If the difference between the two coefficients is less than ????, then the new pixels are modified so that the difference is equal to ????. The proposed method was evaluated on a variety of medical images, including X-ray, CT, US, MRI, and Colonoscopy, and compared to numerous robust watermarking techniques of the recent time. The experimental results demonstrate that the suggested method outperforms contemporary robust watermarking techniques in terms of imperceptibility, robustness, and security. The peak signal noise ratio (PSNR) for all modalities of watermarked medical images exceeds 54 dB, and the average PSNR is approximately 56 dB. The proposed method is outstanding compared to Coltuc's method due to a 93% and 14% increase in bit error rate (BER) and normalized correlation (NC), respectively. Our work is superior to various state-of-the-art robust watermarking techniques, allowing it to be employed effectively in medical applications.</p> <p><strong><em>ABSTRAK: </em></strong>Data sensitif termasuk imej perubatan dan rekod pesakit elektronik (EPR) mempunyai potensi nilai dalam era aplikasi data besar dan teleperubatan. Pengedaran imej perubatan dan EPR melalui rangkaian awam memerlukan tahap privasi dan keselamatan yang tinggi. Teknik penanda air yang mantap dan tidak dapat dilihat diperlukan untuk menyediakan pemeliharaan hak cipta untuk imej perubatan dan melindungi keselamatan maklumat pesakit. Kertas kerja ini menambah baik teknik Coltuc et al. dengan mengubah suai pasangan pekali transformasi kosinus diskret (DCT) dalam formula pembenaman tera air. Formula yang dicadangkan kami memastikan bahawa perbezaan antara dua pekali adalah sekurang-kurangnya ????. Jika perbezaan antara dua pekali kurang daripada ????, maka piksel baharu diubah suai supaya perbezaannya sama dengan ????. Kaedah yang dicadangkan telah dinilai pada pelbagai imej perubatan, termasuk X-ray, CT, US, MRI, dan Kolonoskopi, dan dibandingkan dengan banyak teknik penanda air yang mantap pada masa terkini. Keputusan eksperimen menunjukkan bahawa kaedah yang dicadangkan mengatasi teknik penanda air teguh kontemporari dari segi ketidakjelasan, keteguhan dan keselamatan. Nilai PSNR untuk semua modalitas imej perubatan bertanda air melebihi 54 dB, dan nilai purata PSNR adalah lebih kurang 56 dB. Kaedah yang dicadangkan adalah cemerlang daripada kaedah Coltuc kerana masing-masing peningkatan 93% dan 14% dalam BER dan NC. Kerja kami lebih unggul daripada pelbagai teknik penanda air teguh terkini, membolehkan ia digunakan dengan berkesan dalam aplikasi perubatan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2625 Multi-Objective Mayfly Optimization in Phase Optimization of OFDM 2023-01-04T00:21:38+08:00 Abdul Azeez abdulazeez.ec@outlook.com Suraiya Tarannum suraiyat.ec@hkbk.edu.in <p>Communication systems have been used tremendously in recent years which results in the need for high data transmission rates. Orthogonal Frequency Division Multiplexing (OFDM) provides robust performance in frequency selective fading due to high bandwidth efficiency and inter-symbol interference. Various optimization techniques were applied in existing research to increase the efficiency of OFDM in a communication system. The existing research has a limitation of considering a single objective to improve the efficiency of OFDM and also has a local optima trap. This research proposes a Multi-Objective Mayfly algorithm (MOMF) to consider multi-objective and provides a proper trade-off between exploration and exploitation. The Partial Transmit Sequence (PTS) is applied in the model to test the performance. The FFT sizes and modulation orders are varied to evaluate the performance of the MOMF technique in phase optimization. The MOMF technique effectively increases the performance of the model than other existing optimization techniques. The MOMF technique provides a non-dominated solution to escape from local optima trap. The MOMF model considers PAPR, BER, and SER in MIMO-OFDM system to increase the efficiency of the system. The exploration-exploitation trade-off helps to improve the convergence and overcome local optima trap. The MOMF in OFDM phase optimization was evaluated using BER, SER, and Peak-to-Average Power Ratio (PAPR) metrics. The MOMF method has PAPR of 3.95 dB and PSO-GWO method has 4.92 dB of PAPR.</p> <p><strong><em>ABSTRAK:</em></strong> Sistem komunikasi telah digunakan secara meluas sejak beberapa tahun ini dan dapatan kajian menunjukkan keperluan pada kadar transmisi data yang tinggi. Pemultipleksan Bahagian Frekuensi Ortogon (OFDM) menyediakan prestasi berkesan dalam pemilihan pemudaran frekuensi berdasarkan keberkesanan lebar jalur tinggi dan gangguan antara-simbol. Pelbagai teknik optimum digunakan pada kajian sebelum ini bagi meningkatkan keberkesanan OFDM dalam sistem komunikasi. Kajian tersebut mempunyai kekurangan dalam memilih satu objektif bagi membaiki keberkesanan OFDM dan juga mempunyai perangkap optima setempat. Kajian ini mencadangkan algoritma Mayfly Objektif-Pelbagai (MOMF) bagi memilih objektif-pelbagai dan menyediakan keseimbangan yang wajar antara eksplorasi dan eksploitasi. Urutan Pancar Separa (PTS) telah digunakan dalam model ini bagi menguji prestasi. Saiz FFT dan turutan modulasi dipelbagaikan bagi menguji keberkesanan teknik MOMF pada fasa pengoptimuman. Teknik MOMF dengan berkesan menaikkan prestasi model ini berbanding teknik-teknik sedia ada yang lain. Teknik MOMF menyediakan solusi kepada teknik bukan-dominasi bagi mengelak perangkap optima setempat. Model MOMF ini mengambil kira PAPR, BER, dan SER dalam sistem MIMO-OFDM bagi meningkatkan kecekapan sistem. Keseimbangan yang wajar antara eksplorasi-eksploitasi membantu dalam membaiki penumpuan dan mengatasi perangkap optima setempat. MOMF dalam fasa optimanisasi OFDM telah dinilai menggunakan BER, SER, dan matrik Nisbah Kuasa Puncak-kepada-Purata (PAPR). Kaedah MOMF mempunyai nilai PAPR sebanyak 3.95 dB dan kaedah PSO-GWO mempunyai PAPR 4.92 dB.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2505 Design of Miniaturized Antenna for IoT Applications Using Metamaterial 2023-01-04T00:22:02+08:00 Ahmad Zamani Jusoh azamani@iium.edu.my Nur Fatihah Husain tihah0704@gmail.com Norun Farihah Abdul Malek norun@iium.edu.my Farah Nadia Mohd Isa farahn@iium.edu.my Sarah Yasmin Mohamad smohamad@iium.edu.my <p>With the accelerated development of wireless technology, miniaturized antennae have become outstandingly favored due to the growing demand of Internet of Things (IoT) devices that are essential to accommodate low power, high data rates, and long-range communication. When an antenna operates at lower frequencies, the size of the antenna becomes bulky, which has raised an issue in the integration of the antennae within IoT devices due to their size constraints. Hence, in this paper, a miniaturized ring-monopole antenna incorporated with Rectangular Complementary Split Ring Resonator (RCSRR) and slotted ground plane, was designed at 2.4 GHz and 5.8 GHz frequency bands. The antenna was miniaturized by 46.8 % with overall size of 30 mm x 24.8 mm x 1.6 mm, and it was printed on FR-4 substrate with dielectric constant of 4.3. Design optimization was carried out by modifying the antenna structure, optimizing the dimensions, and using a low loss Rogers RT5880 substrate with a dielectric constant of 2.2, and thickness of 1.575 mm. The width of the antenna was also reduced to 20 mm which furthered the size reduction to 57.8 %. From the simulation results, the antenna was operated at 2.448 GHz, 2.864 GHz, and 5.8 GHz frequency bands with good return loss at -13.872 dB, -33.491 dB, and -19.3 dB respectively. The antenna fabrication and measurement were also implemented to the best simulated design using different substrates to validate its performance by comparing the simulated results with the measured results.</p> <p><strong><em>ABSTRAK: </em></strong>Dengan perkembangan pesat teknologi tanpa wayar, antena miniatur telah menjadi sangat digemari kerana permintaan yang semakin meningkat bagi peranti Internet Benda (IoT), iaitu mempunyai kuasa rendah, kadar data yang tinggi dan berkomunikasi jarak jauh. Apabila antena beroperasi pada frekuensi rendah, saiz antena menjadi besar, ini menimbulkan isu kekangan saiz pada antena ketika berada dalam peranti IoT. Oleh itu, kajian ini adalah berkenaan antena ekakutub-gelang kecil yang digabungkan dengan Resonator Gelang Pemisah Pelengkap Segiempat Tepat (RCSRR) dan satah tanah berslot, telah direka bentuk pada jalur frekuensi 2.4 GHz dan 5.8 GHz. Antena telah dikecilkan sebanyak 46.8 % dengan saiz keseluruhan 30 mm x 24.8 mm x 1.6 mm, dan ia dicetak pada substrat FR-4 dengan pemalar dielektrik 4.3. Reka bentuk optimum telah dilakukan dengan mengubah suai struktur antena, berdimensi optimum, menggunakan substrat Rogers RT5880 rendah kuasa dengan pemalar dielektrik 2.2, dan berketebalan 1.575 mm. Lebar antena juga dikurangkan sebanyak 20 mm, ini bermakna pengurangan saiz berjaya ditingkatkan kepada 57.8%. Dapatan simulasi menunjukkan antena telah beroperasi pada jalur frekuensi 2.448 GHz, 2.864 GHz dan 5.8 GHz dengan pengurangan kehilangan pulangan kuasa yang baik iaitu pada -13.872 dB, -33.491 dB dan -19.3 dB masing-masing. Fabrikasi dan pengukuran antena juga telah dilaksanakan pada reka bentuk simulasi terbaik menggunakan substrat yang berbeza bagi mengesahkan kemampuannya dengan membandingkan dapatan simulasi dengan hasil yang diukur.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2611 Comparative Assessment of Numerical Techniques for Weibull Parameters’ Estimation and the Performance of Wind Energy Conversion Systems in Nigeria 2023-01-04T00:21:42+08:00 Ignatius Okakwu igokakwu@yahoo.com Daniel Akinyele akinyelescholar@gmail.com Olakunle Olabode 095082@gmail.com Titus Ajewole toajewole@yahoo.com Emmanuel Oluwasogo olemstag@gmail.com Ajibola Oyedeji oyedeji.ajibola@oouagoiwoye.edu.ng <p>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.</p> <p><strong><em>ABSTRAK: </em></strong>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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2694 Editorial 2023-01-04T00:21:28+08:00 AHM Zahirul Alam zahirulalam@iium.edu.my <h2 style="margin: 18.0pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">CHIEF EDITOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;"><span lang="EN-US">Ahmad Faris Ismail, IIUM, Malaysia</span></p> </blockquote> <h2 style="margin: 5.65pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">TECHNICAL EDITOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;"><span lang="EN-US">Sany Izan Ihsan, IIUM, Malaysia</span></p> </blockquote> <h2 style="margin: 5.65pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">EXECUTIVE EDITOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;"><span lang="EN-US">AHM Zahirul Alam, IIUM, Malaysia</span></p> </blockquote> <h2 style="margin: 5.65pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">ASSOCIATE EDITOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;"><span lang="EN-US">Nor Farahidah Za’bah, IIUM, Malaysia</span></p> </blockquote> <h2 style="margin-left: 0cm; line-height: normal;"><strong><span lang="EN-US">LANGUAGE EDITOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="margin-top: .1pt;"><span lang="EN-US">Lynn Mason, Malaysia</span></p> </blockquote> <h2 style="margin: 6.0pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">COPY EDITOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;"><span lang="EN-US">Hamzah Mohd. Salleh, IIUM, Malaysia</span></p> </blockquote> <h2 style="margin: 6.0pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">MALAY TRANSLATOR</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;"><span lang="EN-US">Nurul Arfah Che Mustapha, IIUM, Malaysia</span></p> </blockquote> <p class="MsoBodyText" style="line-height: 10.85pt;">&nbsp;</p> <h2 style="line-height: 10.75pt; margin: 12.0pt 0cm 6.0pt 0cm;"><strong><span lang="EN-US">EDITORIAL BOARD MEMBERS</span></strong></h2> <blockquote> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Abdullah Al-Mamun, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Abdumalik Rakhimov, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Aishah Najiah Bt. Dahnel, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Alya Naili Binti Rozhan, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Norsinnira Bt. Zainul Azlan, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Hanafy Omar, Saudi Arabia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Hazleen Anuar, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Konstantin Khanin, University of Toronto, Canada</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Ma'an Al-Khatib, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Meftah Hrairi, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Mohamed B. Trabia, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Mohammad S. Alam, Texas A&amp;M University-Kingsville, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Mustafizur Rahman, National University Singapore, Singapore</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Ossama Abdulkhalik, Michigan Technological University, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Mohamed Hadi Habaebi, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Mohd. Sultan Ibrahim Bin Shaik Dawood, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Muhammad Ibn Ibrahimy, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Nor Fadhillah Mohamed Azmin, IIUM, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in 108.55pt .0001pt 5.4pt;">Waqar Asrar, IIUM, Malaysia</p> </blockquote> <p class="MsoBodyText" style="line-height: 98%; margin: 0cm 171.55pt .0001pt 5.4pt;"><span lang="EN-US">&nbsp;</span></p> <h1><strong>INTERNATIONAL ADVISORY COMMITTEE</strong></h1> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">A. Anwar, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Abdul Latif Bin Ahmad, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Farzad Ismail, USM, Pulau Pinang, Malaysia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Hanafy Omar, Saudi Arabia</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Hany Ammar, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Idris Mohammed Bugaje, Nigeria</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">K.B. Ramachandran, India</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Kunzu Abdella, Canada</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Luis Le Moyne, ISAT, University of Burgundy, France</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">M Mujtaba, United Kingdom</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Mohamed AI-Rubei, Ireland</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Mohamed B Trabia, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Syed Kamrul Islam, United States</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Tibor Czigany, Budapest University of Technology and Economics, Hungary</p> <p class="MsoBodyText" style="line-height: 98%; margin: 0in .55pt .0001pt 49.5pt;">Yiu-Wing Mai, The University of Sydney, Australia.</p> <p style="margin-top: 6px; margin-bottom: 6px;">&nbsp;</p> <h2 style="margin: 0cm; margin-bottom: .0001pt;"><strong><span lang="EN-US">AIMS &amp; SCOPE OF IIUM ENGINEERING JOURNAL</span></strong></h2> <p class="MsoBodyText" style="text-align: justify; line-height: 98%; margin-right: 5.6pt;">The <strong>IIUM Engineering Journal</strong>, published biannually (January and July), is a carefully refereed international publication of International Islamic University Malaysia (IIUM). Contributions of high technical merit within the <span style="letter-spacing: -.2pt;">span </span>of engineering disciplines; covering the main <span style="letter-spacing: -.15pt;"> areas </span>of engineering: Electrical and <span style="letter-spacing: -.15pt;"> Computer </span>Engineering; Mechanical and Manufacturing Engineering; Automation <span style="letter-spacing: -.15pt;">and</span> Mechatronics Engineering; Material and Chemical Engineering; Environmental <span style="letter-spacing: -.15pt;">and</span> Civil Engineering; Biotechnology and Bioengineering; Engineering Mathematics and Physics; and Computer Science and Information Technology are considered for publication in this journal. Contributions from <span style="letter-spacing: -.15pt;">other areas </span>of Engineering <span style="letter-spacing: -.15pt;">and </span>Applied Science are also welcomed. The <span style="letter-spacing: -.15pt;">IIUM </span>Engineering Journal publishes contributions under <em>Regular papers and Invited review papers</em>. 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.<span lang="EN-US">&nbsp;</span></p> <h2 style="margin: 5.55pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">REFEREES’ NETWORK</span></strong></h2> <p class="MsoBodyText" style="margin-right: 5.9pt; text-align: justify; text-indent: -.05pt; line-height: 98%;"><span lang="EN-US">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.</span></p> <h2 style="margin: 5.65pt 0cm .0001pt 0cm;"><strong><span lang="EN-US">SUBMISSION OF A MANUSCRIPT</span></strong></h2> <p class="MsoBodyText" style="line-height: 10.7pt;"><span lang="EN-US">A manuscript should be submitted online to the IIUM Engineering Journal website at </span></p> <p class="MsoNormal" style="margin-right: 6.05pt; text-align: justify; line-height: 98%;"><span lang="EN-US" style="line-height: 98%;"><a href="https://journals.iium.edu.my/ejournal"> <span style="font-size: small;">http://journals.iium.edu.my/ejournal</span></a><span style="font-size: small;">. Further correspondence on the status of the paper could be done through the journal website.</span></span></p> <div class="WordSection2"> <p class="MsoBodyText" style="text-align: justify; line-height: 113%; margin: 0cm 5.85pt .0001pt 5.4pt;"><span lang="EN-US">Whilst every effort is made by the publisher and editorial board 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.</span></p> <p class="MsoBodyText" style="text-align: justify; line-height: 113%; margin: 0cm 5.85pt .0001pt 5.4pt;"><span lang="EN-US">&nbsp;</span><span lang="EN-US">&nbsp;</span></p> <p class="MsoNormal" style="text-align: center;" align="center"><img src="https://journals.iium.edu.my/pub/ejournal/public/site/images/zahirul/image001.jpg" alt="" width="231" height="135"></p> <p class="MsoNormal" style="text-align: center; margin-bottom: 0;" align="center"><strong><span lang="EN-US" style="font-size: 13.0pt;">IIUM Engineering Journal</span></strong></p> <p class="MsoNormal" style="text-align: center; margin-bottom: 0;" align="center"><strong><span lang="EN-US" style="font-size: 9.0pt;">ISSN: 1511-788X&nbsp;&nbsp; E-ISSN: 2289-7860</span></strong></p> <p class="MsoNormal" style="text-align: center;" align="center"><span lang="EN-US">&nbsp;</span></p> </div> <p><strong>Published by:</strong> <br><strong>IIUM Press</strong>, <br>International Islamic University Malaysia <br>Jalan Gombak, 53100 Kuala Lumpur, Malaysia <br>Phone (+603) 6421-5014, Fax: (+603) 6421-6298</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2380 Higher Derivative Block Method with Generalised Steplength for Solving First-Order Fuzzy Initial Value Problems 2023-01-04T00:23:49+08:00 Kashif Hussain kashifuum29@gmail.com Oluwaseun Adeyeye adeyeye@uum.edu.my Nazihah Ahmad nazihah@uum.edu.my <p>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.</p> <p><strong><em>ABSTRAK: </em></strong>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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2366 PLC-based PID controller for real-time pH neutralization process using Palm Oil Mill Effluent 2023-01-04T00:23:58+08:00 Azavitra Zainal azavitra@unikl.edu.my Norhaliza Abdul Wahab aliza@fke.utm.my Mohd Ismail Yusof mohdismaily@unikl.edu.my <p>The pH neutralization process is a highly non-linear process and time delay system that is difficult to control and to accurately model mathematically. Therefore, the empirical method, which needs reliable experimental data to represent the process dynamics, is often used. In this paper, the performance of the PLC-based PID controller was studied using a different adjustment of the acid dosing pump stroke rate in the pH neutralization process. The pH neutralization process is a single-input, single-output system where the manipulated variable is the alkali dosing pump stroke rate, the controlled variable is pH, and the acid dosing pump stroke rate is set as a constant. The acid dosing pump stroke rate was adjusted to 10%, 15% and 25%. The results showed that the best performance of the PID controller was based on setpoint tracking when the setting of the acid dosing pump stroke rate was set at 10%, which could be used as experimental data in the empirical method. In addition, the real-time control system was integrated between PLC and MATLAB using National Instruments OPC server to access the experimental data in real-time, conduct simulation, and to develop the advanced control in the future.</p> <p><strong><em>ABSTRAK: </em></strong>Peneutralan pH adalah proses tidak linear yang sukar dikawal dan sukar mendapat model matematik yang tepat. Oleh itu, kaedah empirikal memerlukan data eksperimen masa nyata bagi mewakili proses dinamik untuk mengatasi masalah ini. Kajian ini adalah berkaitan kajian prestasi pengawal PLC-berdasarkan PID menggunakan pelbagai perubahan kadar strok pam dos asid dalam proses peneutralan pH. Proses peneutralan pH ini adalah sistem satu input/output, di mana pemboleh ubah yang dimanipulasi adalah kadar peratusan strok pam dos alkali menggunakan pam peristaltik, pemboleh ubah kawalan ialah pH dan pemboleh ubah malar ialah peratusan dos asid.Kadar strok pam dos asid dilaraskan pada 10%, 15% dan 25%. Dapatan kajian menunjukkan prestasi terbaik kawalan PID adalah berdasarkan pengesan titik-set apabila kadar strok pam dos asid dilaraskan pada 10%, di mana ianya berkesan apabila digunakan sebagai data eksperimen dalam kaedah empirikal. Tambahan, kajian ini telah berjaya membentuk sistem kawalan masa nyata bagi proses penutralan pH menggunakan PLC dan MATLAB melalui pelayan National Instruments OPC bagi membolehkan pertukaran data eksperimen secara masa nyata yang cekap, menjalankan simulasi dan pembangunan kawalan termaju pada masa hadapan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2374 Solar Thermal Process Parameters Forecasting for Evacuated Tubes Collector (ETC) Based on RNN-LSTM 2023-01-04T00:23:54+08:00 Muhammad Ali Akbar aliumer111@gmail.com Ahmad Jazlan ahmadjazlan@iium.edu.my Muhammad Mahbubur Rashid mahbub@iium.edu.my Hasan Firdaus Mohd Zaki hasanzaki@iium.edu.my Muhammad Naveed Akhter naveed.akhter@uet.edu.pk Abd Halim Embong ehalim@iium.edu.my <p>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 &amp; 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.</p> <p><strong><em>ABSTRAK: </em></strong>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 &amp; 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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2529 An Integrated RRT*SMART-A* Algorithm for solving the Global Path Planning Problem in a Static Environment 2023-01-04T00:21:55+08:00 Heru Suwoyo heru.suwoyo@mercubuana.ac.id Andi Adriansyah andi@mercubuana.ac.id Julpri Andika julpri.andika@mercubuana.ac.id Abu Ubaidillah ubaidah@uthm.edu.my Mohamad Fauzi Zakaria mfauzi@uthm.edu.my <p>The 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. </p> <p><strong><em>ABSTRAK: </em></strong>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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2604 Control Strategy for Power Assist Upper Limb Rehabilitation Robot with the Therapist’s Motion Intention Prediction 2023-01-04T00:21:45+08:00 Zulikha Ayomikun Adeola-Bello zabayomikun@gmail.com NORSINNIRA ZAINUL AZLAN sinnira@iium.edu.my SALMAH ANIM ABU HASSAN anim@iium.edu.my <p>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.</p> <p><strong><em>A</em></strong><strong><em>BSTRAK: </em></strong>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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2577 Non-Verbal Human-Robot Interaction Using Neural Network for The Application of Service Robot 2023-01-04T00:21:52+08:00 Zubair Adil Soomro ae180108@siswa.uthm.edu.my ABU UBAIDAH BIN SHAMSUDIN ubaidah@uthm.edu.my Ruzairi Abdul Rahim ruzairi@uthm.edu.my Andi Adrianshah andi@mercubuana.ac.id Mohd Hazeli hazeli@moverobotic.com <p>Service robots are prevailing in many industries to assist humans in conducting repetitive tasks, which require a natural interaction called Human Robot Interaction (HRI). In particular, nonverbal HRI plays an important role in social interactions, which highlights the need to accurately detect the subject's attention by evaluating the programmed cues. In this paper, a conceptual attentiveness model algorithm called Attentive Recognition Model (ARM) is proposed to recognize a person’s attentiveness, which improves the accuracy of detection and subjective experience during nonverbal HRI using three combined detection models: face tracking, iris tracking and eye blinking. The face tracking model was trained using a Long Short-Term Memory (LSTM) neural network, which is based on deep learning. Meanwhile, the iris tracking and eye blinking use a mathematical model. The eye blinking model uses a random face landmark point to calculate the Eye Aspect Ratio (EAR), which is much more reliable compared to the prior method, which could detect a person blinking at a further distance even if the person was not blinking. The conducted experiments for face and iris tracking were able to detect direction up to 2 meters. Meanwhile, the tested eye blinking model gave an accuracy of 83.33% at up to 2 meters. The overall attentive accuracy of ARM was up to 85.7%. The experiments showed that the service robot was able to understand the programmed cues and hence perform certain tasks, such as approaching the interested person.</p> <p><strong><em>A</em></strong><strong><em>BSTRAK:</em></strong> Robot perkhidmatan lazim dalam banyak industri untuk membantu manusia menjalankan tugas berulang, yang memerlukan interaksi semula jadi yang dipanggil Interaksi Robot Manusia (HRI). Khususnya, HRI bukan lisan memainkan peranan penting dalam interaksi sosial, yang menonjolkan keperluan untuk mengesan perhatian subjek dengan tepat dengan menilai isyarat yang diprogramkan. Dalam makalah ini, algoritma model perhatian konseptual yang dipanggil Model Pengecaman Perhatian (ARM) dicadangkan untuk mengenali perhatian seseorang, yang meningkatkan ketepatan pengesanan dan pengalaman subjektif semasa HRI bukan lisan menggunakan tiga model pengesanan gabungan: pengesanan muka, pengesanan iris dan mata berkedip. . Model penjejakan muka telah dilatih menggunakan rangkaian saraf Memori Jangka Pendek Panjang (LSTM), yang berdasarkan pembelajaran mendalam. Manakala, pengesanan iris dan mata berkelip menggunakan model matematik. Model mata berkelip menggunakan titik mercu tanda muka rawak untuk mengira Nisbah Aspek Mata (EAR), yang jauh lebih dipercayai berbanding kaedah sebelumnya, yang boleh mengesan seseorang berkelip pada jarak yang lebih jauh walaupun orang itu tidak berkelip. Eksperimen yang dijalankan untuk pengesanan muka dan iris dapat mengesan arah sehingga 2 meter. Sementara itu, model berkelip mata yang diuji memberikan ketepatan 83.33% sehingga 2 meter. Ketepatan perhatian keseluruhan ARM adalah sehingga 85.7%. Eksperimen menunjukkan bahawa robot perkhidmatan dapat memahami isyarat yang diprogramkan dan seterusnya melaksanakan tugas tertentu, seperti mendekati orang yang berminat.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2642 Repurposing A Sampling-Based Planner for A Six-Degree-Of-Freedom Manipulator to Avoid Unpredictable Obstacles 2023-01-04T00:21:33+08:00 Hafiz Iman hafiz.ghazman@gmail.com Md. Raisuddin Khan raisuddin@iium.edu.my <p>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.</p> <p><strong><em>ABSTRAK</em></strong>: 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.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2223 Terminal Control Area Complexity Measurement Using Simulation Model 2023-01-04T00:24:08+08:00 Rully Medianto rully.medianto@itda.ac.id Naflah Mutiara Adinda adindapane14@gmail.com Yazdi Ibrahim Jenie yazdijenie@ae.itb.ac.id Hisar Manongam Pasaribu hmpasaribu@ae.itb.ac.id Hari Muhammad hari@ftmd.itb.ac.id <p>Traffic density in the terminal control area will increase flight safety risks. One effort to reduce the risk is to minimize the controller’s workload when affected by air traffic complexity. This research uses a simulation model to measure air traffic complexity in terminal control areas. The aircraft performance model has been constructed from ADS-B data and represents the aircraft movement in the terminal control area of Soekarno-Hatta International Airport. The simulation model can detect and resolve conflicts to keep separations between aircraft at a specified minimum separation limit. Air traffic complexity measurement uses several indicators, i.e., aircraft density, number of climbing and descending aircraft, aircraft type mixing, conflict control, aircraft speed difference, and controller communication. The weighting factor for each indicator has been obtained from Jakarta Air Traffic Service Center (JATSC) controller perception using an analytic hierarchy process. The simulation results show that the variation of resolution type affects the complexity level significantly. The results of this study can be used as consideration for improving air traffic control procedures and air space structures.</p> <p><strong><em>ABSTRAK: </em></strong>Kepadatan trafik di kawasan terminal kawalan bakal menyebabkan peningkatan risiko keselamatan penerbangan. Salah satu cara bagi mengurangkan risiko adalah dengan meminimumkan beban kerja pengawal yang terlibat dengan kesesakan trafik udara. Kajian ini menggunakan model simulasi bagi mengukur kesesakan trafik udara di kawasan terminal kawalan. Model pretasi pesawat telah dibina menggunakan data ADS-B dan ini mewakili pergerakan pesawat di terminal kawalan lapangan terbang antarabangsa Soekarno-Hatta. Model simulasi ini dapat mengesan konflik dan membuat resolusi bagi mengekalkan penjarakan antara pesawat mengikut had penjarakan minimum yang ditetapkan. Beberapa indikator telah digunakan bagi mengukur kerumitan trafik udara, iaitu: ketumpatan pesawat, bilangan pesawat mendaki dan menurun, jenis pesawat, kawalan konflik, perbezaan kelajuan pesawat dan pengawal komunikasi. Faktor pemberat bagi setiap indikator telah diperoleh daripada pengawal persepsi Pusat Servis Trafik Udara Jakarta (JATSC) menggunakan proses analisis hierarki. Keputusan simulasi menunjukkan pelbagai jenis resolusi mempengaruhi tahap kerumitan dengan ketara. Hasil kajian ini boleh digunakan bagi menambah baik prosedur kawalan trafik udara dan struktur ruang udara.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2341 Performance Comparison Between Predictive Functional Control and PID Algorithms for an Automobile Cruise Control System 2023-01-04T00:24:03+08:00 Mohamed Al-Sideque Zainuddin alsideque@mara.gov.my Muhammad Abdullah mohd_abdl@iium.edu.my Salmiah Ahmad salmiah@iium.edu.my Mohd Suhaimi Uzir suhaimiu@proton.com Zaid Mujaiyid Putra Ahmad Baidowi zaidmu2889@uitm.edu.my <p>This paper presents the performance analysis of Predictive Functional Control (PFC) for Adaptive Cruise Control (ACC) application. To cope with multiple driving objectives of modern ACC systems such as passenger comfort, safe distancing, and fast time response, an advanced optimal controller such as Model Predictive Control (MPC) is often used. Nevertheless, MPC requires a high computation load due to its complex formulation and may overload the processing power of a microcontroller. Thus, the prime objective of this work is to propose a PFC algorithm as an alternative controller, while providing a formal comparison between MPC and the traditional Proportional Integral (PI) controller. A standard kinematic model for vehicle longitudinal dynamics was modelled and used to derive the control law of PFC. Since the open-loop dynamic of the derived transfer function is not stable, the second objective is to propose a pre-stabilized loop or cascade PFC structure for the system. A complete tuning procedure and analysis were presented. The simulation result shows that although MPC performance is the best for the ACC application with Root Mean Square Error (RMSE) of 1.4873, PFC has shown a promising response with RMSE of 1.5501, which is better compared to the PI controller with RMSE of 1.6219. All the imposed driving constraints such as maximum acceleration, maximum deceleration and safe distance were satisfied in the car following application. Thus, the findings from this work can become a good initial motivation to further explore the capability of the PFC algorithm for future ACC development. </p> <p><strong><em>ABSTRAK: </em></strong>Kajian ini adalah berkenaan analisis prestasi Kawalan Fungsi Ramalan (PFC) aplikasi Kawalan Mudah Suai (ACC). Bagi memenuhi pelbagai keperluan objektif sistem pemanduan moden ACC seperti keselesaan penumpang, penjarakan selamat dan tindak balas pantas, kawalan optimum terbaru seperti Model Kawalan Ramalan (MPC) sering digunakan. Walau bagaimanapun, MPC memerlukan beban pengiraan tinggi kerana rumusnya yang kompleks dan mungkin mengakibatkan beban berlebihan kuasa pemprosesan mikrokawalan. Oleh itu, matlamat utama kajian ini adalah bagi mencadangkan algoritma PFC yang mempunyai pengiraan mudah sebagai kawalan alternatif, sementara menyediakan perbandingan formal antara MPC dan kawalan tradisional Berkadar Keseluruhan (PI). Oleh kerana model ini tidak stabil, objektif kedua adalah mencadangkan penggunaan struktur PFC berlapis bagi menstabilkan sistem terlebih dahulu sebelum algorithma kawalan digunakan atau dengan menggunakan struktur PFC secara berturut pada sistem. Prosedur lengkap dan terperinci untuk analisis PFC dibentangkan. Dapatan simulasi kajian menunjukkan walaupun prestasi MPC adalah baik bagi aplikasi ACC dengan Ralat Punca Min Kuasa Dua (RMSE) bernilai 1.4873, namun PFC menunjukkan tindak balas baik dengan RMSE bernilai 1.5501 berbanding kawalan PI yang mempunyai RMSE sebanyak 1.6219. Kesemua kekangan seperti pecutan dan nyahpecutan maksima, dan penjarakan selamat bertepatan dengan aplikasi kenderaan ini. Dengan itu, penemuan ini adalah motivasi awal yang baik bagi meneroka lebih jauh keupayaan algoritma PFC bagi membangun ACC pada masa hadapan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press https://journals.iium.edu.my/ejournal/index.php/iiumej/article/view/2448 The Ricochet of Spinning Spheres Off Water 2023-01-04T00:22:07+08:00 Riyah Najim Kiter riyahkiter@gmail.com Mazin Yaseen Abbood mazin76eng@gmail.com Omar Hassoon omar.h.hassoon@uotechnology.edu.iq <p>Liquid impact and ricochet is still attracting researchers interested in the field of hydrodynamics and naval engineering. The ricochet from a water surface experienced by spinning spheres was examined both analytically and numerically. A theoretical analysis was made to quantify the enhancement attained by imparting backspin to the sphere. Numerical simulation of the process was conducted by implementing ABAQUS software. The mathematical analysis and the simulation were built on the assumption that the effects of cavitation, splash, and two phase flow are negligible compared to hydro-dynamical forces of lift and drag. It was proven that both mathematical analysis and simulation were capable of predicting the trajectory of a spinning sphere during its course of entry into the water. Aspects like the critical angle of ricochet and the maximum depth of immersion were extracted from these trajectories and compared with available data. It was found that the analytical and numerical results were generally validated with respect to each other as well as to existing findings. Aluminum () spinning spheres, of radius 10 mm and speed of 10 m/sec, were examined. It was found that a 300 rad/sec backspin improves the critical angle of ricochet from 10.43 to 12.5 deg and increases the maximum depth of immersion from 1.52 to 1.83. "Magnus Effect" usually acting on a fully immersed spinning sphere, was described and relations estimating the hydrodynamic forces were deduced.</p> <p><strong><em>ABSTRAK: </em></strong>Keadaan pertumbuhan bakteria penghasil enzim protease aktif-sejuk terasing daripada sampel Antartika disaring menggunakan satu-faktor-satu-masa (OFAT). Kemudian, enzim protease ini diekstrak pada lewat fasa logaritma untuk ujian enzimatik. Strain yang menunjukkan aktiviti enzim tertinggi telah dipilih bagi tujuan pengoptimuman melalui Kaedah Permukaan Tindak Balas (RSM). Parameter yang dikaji adalah pada suhu pengeraman (4 - 36 °C), media pH (4 – 10) dan kepekatan NaCl (0 - 8 %). Berdasarkan dapatan OFAT, kesemua lapan bakteria menunjukkan kadar pertumbuhan tertinggi pada 20 °C, pH 7 dan 4% NaCl (w/v). Hasil ujian enzimatik menunjukkan enzim protease mentah yang diekstrak daripada SC8 menunjukkan 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 ini menunjukkan kadar optimum bagi pertumbuhan SC8 adalah pada 20.5 °C, pH 6.83 dan 2.05% NaCl (w/v) dengan dapatan kadar pertumbuhan bakteria pada 3.70 ± 0.06 x 10<sup>6</sup> sel/jam. Keadaan pertumbuhan optimum SC8 melalui kajian ini bermanfaat bagi menghasilkan produk protease aktif-sejuk secara besar-besaran pada masa hadapan.</p> 2023-01-04T00:00:00+08:00 Copyright (c) 2022 IIUM Press