{"id":6093,"date":"2026-08-30T14:38:54","date_gmt":"2026-08-30T06:38:54","guid":{"rendered":"https:\/\/www.ukm.my\/jkukm\/?page_id=6093"},"modified":"2026-08-30T14:43:58","modified_gmt":"2026-08-30T06:43:58","slug":"volume-3805-2026","status":"publish","type":"page","link":"https:\/\/www.ukm.my\/jkukm\/volume-3805-2026\/","title":{"rendered":"Volume 38 (05) August 2026"},"content":{"rendered":"\t\t
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Volume 38 (05) August 2026<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Table of Content<\/a><\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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No.<\/strong><\/td>Article<\/strong><\/td>Page<\/strong><\/td><\/tr>\r\n
1.<\/td>\r\n \r\n \r\n


Carbon Footprint of Food Waste for Campus Sustainability: Insights from UniKL MICET<\/b><\/a><\/p>\r\n

Mohd Syazwan Mohd Ghazali*, Muazzin Mupit, Mohd Edyazuan Azin, Zaihar Yaacob, Ahmad Azhari Hamzah, Mohamad Zulkeflee Sabri & Khairul Naidah Ibrahim<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Inefficient food waste management poses significant environmental challenges, particularly through the release of methane, a potent greenhouse gas. This study quantifies the carbon footprint of campus food waste at Universiti Kuala Lumpur Malaysian Institute of Chemical & Bioengineering Technology (UniKL MICET) and provides baseline evidence for evaluating the sustainability performance of existing waste management practices. A campus-based food waste audit was conducted across three sampling cycles, covering all cafeterias and two collection points (CPs), and food waste was categorized into animal-based, plant-based, and spoiled food. Carbon emissions were estimated using both generalized and type-specific emission factors. Results indicate that the majority of waste (96%) originates from campus cafeterias, with animal-based food contributing disproportionately to emissions. The total greenhouse gas emissions per sampling cycle were estimated at 150.3 kg CO2<\/sub>-eq, translating to an annual potential of 12.21 tonnes CO2<\/sub>-eq. Animal-based waste, although only 24.5% of the total mass, accounted for over half of total emissions, emphasizing its high carbon intensity. Plant-based and spoiled food contributed comparatively lower emissions. These findings provide a basis for designing targeted interventions to reduce campus food waste and mitigate its environmental impact. The study supports Sustainable Development Goal 12 and 13, offering insights to advance a circular, low-carbon food system on campus.<\/p>\r\n

Food waste; carbon footprint; campus sustainability; greenhouse gas emissions; emission factors<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-01\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2087-2095<\/span>\r\n <\/td>\r\n <\/tr>\r\n
2.<\/td>\r\n \r\n \r\n


Glycerol Acetylation with Acetic Acid to Produce Triacetin using Modified Canature 001x8FG as Heterogeneous Catalyst<\/b><\/a><\/p>\r\n

Muhammad Hazreen Danish Mohd Hasnor, Chee Sien Wong, Rapidah Othman & Lip Han Chin*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The fast increase in biodiesel production has resulted in an excess of glycerol, a key byproduct that requires effective valorization solutions. This research looks at acetylation of glycerol with acetic acid as a sustainable way to manufacture triacetin, a high-value fuel additive. Canature 001x8FG, a heterogeneous ion-exchange resin catalyst, was tested in its unmodified, modified (sulfonated), and uncatalyzed forms. Batch studies were carried out utilizing a reflux condenser and mechanical stirring, and the product was analyzed using gas chromatography. The modified Canature resin was made by treating it with 0.1 M sulfuric acid. The sulfonated resin displayed better catalytic efficiency, attaining up to 100% glycerol conversion under ideal conditions defined by Response Surface Methodology (RSM): 95 \u00b0C, 11:1 acetic acid-to-glycerol molar ratio, and 1.5-hour reaction duration. Triacetin was the most common product under these circumstances. At 95 \u00b0C with a 6:1 ratio and 1.5 hours, the modified resin converted about 70% of glycerol, whereas the original resin only converted 13%. The uncatalyzed process demonstrated insignificant conversion. FTIR-ATR analysis indicated effective sulfonation, with the improved catalyst showing stronger -SO3<\/sub>H (S=O and S-O) stretching bands at 1171, 1125, and 1035 cm-1<\/sup>. Increased Br\u00f8nsted-acid site density leads to higher catalytic efficiency and selectivity for triacetin. These results emphasize the importance of chemical modification in increasing resin catalyst activity and show the potential of sulfonated Canature 001X8FG resin as a viable heterogeneous catalyst for glycerol valorization in biodiesel-related processes.<\/p>\r\n

Glycerol acetylation; triacetin; ion-exchange resin; sulfonation; heterogeneous catalysis<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-02\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2097-2107<\/span>\r\n <\/td>\r\n <\/tr>\r\n
3.<\/td>\r\n \r\n \r\n


Proof-of-Concept Conversion of Nitrile Rubber Gloves into Durable Biochar Briquettes Using Sawdust Binder for Sustainable Energy Recovery<\/b><\/a><\/p>\r\n

Siti Abd Halim*, Hawa Ali Mohamed, Noor Aina Mohd Nazri & Mohd Zul Hilmi Mayzan<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The increasing generation of disposable nitrile rubber gloves has raised environmental concerns due to their non-biodegradable nature and limited recycling options. This study presents a proof-of-concept approach for converting clean and unused nitrile butadiene rubber (NBR) gloves, used as a model material for glove waste, into biochar briquettes through pyrolysis and sawdust-assisted densification. Pyrolysis was conducted at 300, 350, 400, and 450 \u00b0C under an inert atmosphere. The material treated at 300 \u00b0C retained rubber-like elasticity and was therefore not considered viable biochar, whereas pyrolysis at 350, 400, and 450 \u00b0C produced solid carbonaceous residues with biochar yields of 68.4%, 48.5%, and 13.5%, respectively. Biochar produced at 350 \u00b0C was selected for briquette preparation because it provided the best balance between solid recovery and physical conversion into a brittle carbonaceous material. Sawdust was incorporated as a natural lignocellulosic binder at 0, 10, 20, and 30 wt.%, and the mixtures were densified at 200 \u00b0C and 3 MPa. The 20 wt.% sawdust formulation showed the best overall performance, with a hardness of 93.6, pellet durability index of 99.6%, water absorptivity of approximately 22%, and heating value of 17.40 MJ\/kg. Although sawdust enhanced briquette binding, excessive sawdust addition increased water uptake because of its hydrophilic structure, which may affect storage stability and combustion performance. These findings demonstrate the potential of sawdust-bound NBR-derived biochar briquettes as sustainable solid fuel materials; however, further validation using actual contaminated medical glove waste is required.<\/p>\r\n

Nitrile rubber gloves; biochar briquettes; pyrolysis; sawdust binder<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-03\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2109-2130<\/span>\r\n <\/td>\r\n <\/tr>\r\n
4.<\/td>\r\n \r\n \r\n


Sustainable Conversion of Palm Kernel Shell Biomass to Acid-Functionalized Graphene Oxide<\/b><\/a><\/p>\r\n

Nurul Hannan Ahmad Uma, Rapidah Othman, Lip Han Chin & Chee Sien Wong*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The development of sustainable carbon-based nanomaterials has stimulated increasing interest in the use of biomass-derived precursors for graphene oxide (GO) synthesis. However, studies utilizing palm kernel shell (PKS), an abundant agricultural by-product generated from palm oil processing, remain limited despite its high carbon content and availability, particularly in palm oil-producing regions like Malaysia. This study investigates the feasibility of synthesizing GO from PKS using Tour\u2019s method and explores its subsequent functionalization with varying concentrations of nitric acid (0.2 M to 1.0 M) to enhance acidity. The synthesized and functionalized GO were analyzed using Fourier-transform infrared spectroscopy (FTIR), UV\u2013visible spectroscopy (UV\u2013Vis), and thermogravimetric analysis (TGA) to characterize the oxidation level, functional groups, and thermal stability. FTIR analysis confirmed the introduction of oxygen-containing functional groups onto the GO surface, while UV-Vis spectroscopy revealed characteristic absorption peaks confirming successful oxidation and exfoliation of the carbonized PKS. TGA demonstrated reduced thermal stability of GO compared to carbonized PKS, consistent with the incorporation of thermally unstable oxygen functionalities. Functionalization with nitric acid resulted in a gradual decrease in pH from 2.06 (untreated GO) to 1.68 (GO functionalized with 1.0 M HNO3 ), indicating improved surface acidity. This pH reduction followed a non-linear trend with a plateau beyond 0.8 M HNO3 , suggesting saturation of available reactive sites on the GO surface that limits further functionalization. The findings demonstrate that PKS is a viable and sustainable precursor for GO synthesis and that functionalization with nitric acid can effectively modulate its surface acidity for potential future applications.<\/p>\r\n

Graphene Oxide, Palm Kernel Shell, Tour\u2019s Method, Functionalization, Surface Acidity<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-04\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2131-2139<\/span>\r\n <\/td>\r\n <\/tr>\r\n
5.<\/td>\r\n \r\n \r\n


Biomass-Derived Graphene Oxide in Heterogeneous Catalysis: A Review of Synthesis, Functionalization, and Reaction Kinetics<\/b><\/a><\/p>\r\n

Afiq Hakimi Hamdan, Rapidah Othman, Lip Han Chin & Chee Sien Wong*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Graphene oxide (GO) has emerged as a versatile nanomaterial in heterogeneous catalysis due to its twodimensional structure, high surface area, and tunable surface chemistry. This review critically addresses whether biomass-derived GO can replace conventional graphite-based GO without sacrificing catalytic performance. To answer this, recent advances are examined in three interrelated areas: the sustainable synthesis of GO from biomass-derived precursors, functionalization strategies used to tailor its surface properties, and kinetic studies of reactions using GO and functionalized GO (FGO). Biomass-based synthesis routes via hydrothermal treatment, pyrolysis, and modified Hummers methods offer an environmentally friendly alternative to conventional graphite processing. These methods produce GO with surface area and oxygen content comparable to graphite-derived GO, while reducing reliance on non-renewable resources and supporting waste recycling. Both covalent and noncovalent functionalization approaches are critically compared. Covalent methods enhance stability and active site density, whereas non-covalent methods better preserve GO\u2019s structure. Particular attention is given to kinetic studies, which provide insights into how surface chemistry and functional group distribution influence reaction rates. The review concludes that with optimized synthesis and functionalization, biomass-derived GO can achieve catalytic performance comparable to graphite-derived GO while offering a lower environmental footprint. Nevertheless, additional research into scalable production and mechanistic kinetics is still required.<\/p>\r\n

Graphene oxide; functionalization; reaction kinetics; biomass; heterogeneous catalysis<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-05\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2141-2152<\/span>\r\n <\/td>\r\n <\/tr>\r\n
6.<\/td>\r\n \r\n \r\n


Mechanical Properties and Image-Based Crack Analysis of Hydrogenated Cup Lump Natural Rubber-Modified Asphalt Mixtures<\/b><\/a><\/p>\r\n

Lillian Gungat*, Nur Syazleen Hamsah, Nur Izzi Md Yusoff, Siti Fairus M. Yusoff, Nurmin Bolong, Noumie Surugau & Mohd Rosli Hainin<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Researchers have explored the effects of incorporating cup lump natural rubber as an asphalt modification to promote rubber utilization and enhance pavement performance. However, cup-lump natural rubber treatment affects the performance of asphalt mixtures. This study investigates how cup-lump natural rubber treated via non-catalytic hydrogenation to create hydrogenated cup-lump natural rubber (HCLNR) affects the mechanical performance of asphalt mixtures. Asphalt mixtures were prepared by incorporating HCLNR at 2.5%, 5.0%, 7.5% and 10% by weight of bitumen. The performance was evaluated through Marshall stability, indirect tensile strength, and tensile strength ratio (TSR) tests, complemented by a MATLAB-based digital image analysis to quantify surface cracking and pattern. Results indicate that all HCLNR-modified mixtures comply with Malaysian Public Works Department specifications. The 5.0% HCLNR dosage was identified as the optimum content, achieving a peak Marshall stability of 13.1 kN and tensile strength of 862.08 kPa. Furthermore, the optimal dosage enhanced moisture resistance, with a TSR of 87.09% and the lowest crack ratio. Higher rubber contents increased bitumen stiffness and led to poor dispersion and brittle fracture patterns. This study confirms that HCLNR at moderate dosages serves as a sustainable and high-performance modifier, effectively improving the durability and crack resistance of asphalt pavements in tropical climates.<\/p>\r\n

Hydrogenated cup lump natural rubber; asphalt modification; Indirect Tensile Strength; Tensile Strength Ratio; crack analysis<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-06\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2153-2161<\/span>\r\n <\/td>\r\n <\/tr>\r\n
7.<\/td>\r\n \r\n \r\n


Effect of Hot Water Treatment on Physical and Mechanical Properties of Oil Palm Empty Fruit Bunch Fibre Cement Boards<\/b><\/a><\/p>\r\n

Nurul Huda Azmi, Mohammad Soffi Md Noh* & Nik Mohd Zaini Nik Soh<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The growing demand for sustainable construction materials has increased interest in fibre\u2013cement composites reinforced with natural fibres. Oil palm empty fruit bunch (OPEFB) is an abundant agricultural by-product with strong potential for fibre cement boards. However, its hydrophilic nature and weak fibre\u2013matrix adhesion limit dimensional stability and mechanical performance. While hot water treatment has been shown to improve fibre compatibility, most studies have focused only on untreated, 60\u00b0C, and 100\u00b0C conditions, leaving the effects of intermediate temperatures insufficiently explored. This study investigates the effect of hot water treatment at six temperatures (room temperature, 60\u00b0C, 70\u00b0C, 80\u00b0C, 90\u00b0C, and 100\u00b0C) for 60 minutes on the physical and mechanical properties of OPEFB fibre cement boards. Treatment effectiveness was evaluated using water absorption, thickness swelling, density, modulus of rupture, modulus of elasticity, and internal bonding tests, with standard sample dimensions of 100 \u00d7 100 mm, 50 \u00d7 50 mm, and 300 \u00d7 50 mm. The results showed that hot water treatment significantly enhanced dimensional stability and mechanical performance. Boards treated at 100\u00b0C exhibited the lowest water absorption (25.14%) and thickness swelling (0.39%), as well as the highest modulus of rupture (5.23 N\/ mm\u00b2), modulus of elasticity (4180.50 N\/mm\u00b2), internal bonding strength (1.22 N\/mm\u00b2), and density (1321.72 kg\/m\u00b3). Treatments at intermediate temperatures (70\u201390\u00b0C) also produced substantial improvements, indicating that effective fibre modification can be achieved below boiling temperature. These findings demonstrate that hot water treatment is a cost-effective, solvent-free, and environmentally sustainable approach for enhancing OPEFB fibre cement boards, supporting their potential as eco-friendly construction materials.<\/p>\r\n

Oil palm empty fruit bunch; fibre cement board; hot water treatment; physical properties; mechanical properties<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-07\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2163-2174<\/span>\r\n <\/td>\r\n <\/tr>\r\n
8.<\/td>\r\n \r\n \r\n


Penilaian dan Pengelasan Siderofor yang Dihasilkan oleh Brevibacterium<\/i> sp. pencilan NII<\/b><\/a><\/p>\r\n

Evaluation and Classification of Siderophores Produced by Brevibacterium<\/i> sp. isolate NII<\/em><\/b><\/a><\/p>\r\n

Muhammad Ezzul Faiq Mohd Effendi, Nur 'Izzati Ismail, Nurull Muna Daud & Md Nabil Aizat Junaidi @ Addie*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Siderophores are iron (Fe)-chelating molecules produced by microorganisms under iron-limiting conditions, and they help microbes acquire Fe from the environment. These molecules are also of interest for applications because they can enhance Fe availability in a given system. This study evaluated the ability of Brevibacterium sp. isolate NII to produce siderophores and to determine the siderophore group produced. Siderophore production was assessed qualitatively using the Chrome Azurol S (CAS) agar assay and quantitatively using a liquid CAS assay monitored for seven days. For the quantitative assay, absorbance at 630 nm was used to calculate the percentage of siderophore units, readings were taken after the culture supernatant was reacted with the CAS reagent for 30 minutes at room temperature. Siderophore classification was carried out using FeCl3, Arnow, and acid-based tests, while Fourier-transform infrared (FTIR) spectroscopy was performed to support functional-group identification. Qualitatively, a distinct color change from blue to orange around the bacterial colonies indicated siderophore secretion. The liquid CAS assay showed an increase in siderophore production from 24.9% to 54.3% over the seven-day period, indicating timedependent production during incubation. For classification, a positive FeCl3<\/sub> reaction (orange coloration) suggested that the siderophores produced were most consistent with the hydroxamate group, whereas negative results from the Arnow and acid-based tests indicated no evidence of catecholate or carboxylate groups in the sample. FTIR analysis further showed major absorption bands consistent with hydroxamate-related functional groups, supporting the biochemical test findings. Overall, these results confirm that Brevibacterium sp. isolate NII actively produces hydroxamate-type siderophores and provide an initial indication of potential for further exploration in Ferelated applications, including future bioremediation studies.<\/p>\r\n

Brevibacterium sp. isolate NII; Chrome Azurol S; catecholate; hydroxamate; carboxylate<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-08\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2175-2185<\/span>\r\n <\/td>\r\n <\/tr>\r\n
9.<\/td>\r\n \r\n \r\n


Machine Learning-Based Non-Intrusive Load Monitoring for Three-Phase Smart Energy Consumption Disaggregation<\/b><\/a><\/p>\r\n

Tan Rui Lin, Md Mahadi Hasan Imran, Muhamad Zalani Daud*, Wan Hafiza Wan Hassan & Noraziah Muda<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Non-Intrusive Load Monitoring (NILM) has emerged as a pivotal technology for promoting energy efficiency and sustainability by disaggregating aggregate household or industrial energy consumption into appliance-level usage profiles. This capability enables consumers and utilities to gain deeper insights into consumption behavior, reduce wastage, and improve energy management practices. In this study, a machine learning-based NILM framework is presented, focusing on enhancing accuracy, adaptability, and scalability across three-phase energy systems, which are common in residential and industrial applications. The proposed approach employs the Cubic K-Nearest Neighbor (Cubic KNN) algorithm for effective classification and disaggregation of energy data. Unlike traditional NILM methods, the Cubic KNN model demonstrates robustness in handling challenges such as low sampling rates, overlapping appliance signatures, multi-state appliances, and dynamic operational profiles. The methodology integrates feature extraction, supervised machine learning, and rigorous validation against realworld energy data obtained from a Tenaga Nasional Berhad (TNB) household smart meter. Both online and offline energy monitoring and data logging systems were developed to ensure data reliability and continuity. Experimental evaluations show that the Cubic KNN classifier achieves high accuracy, exceeding 95% for most appliances, with negligible misclassification errors. Furthermore, comparative analysis against utility billing data confirms the reliability of the proposed system, with overall error rates below 6%. The findings underscore the potential of advanced machine learning algorithms in NILM applications, contributing toward the development of scalable, efficient, and accurate solutions. This research highlights the role of NILM in supporting smarter energy monitoring, conservation initiatives, and sustainable energy management strategies for future smart grid systems.<\/p>\r\n

NILM; energy efficiency; energy consumption; machine learning<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-09\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2187-2201<\/span>\r\n <\/td>\r\n <\/tr>\r\n
10.<\/td>\r\n \r\n \r\n


Lignin Extraction from Coconut Pith by Alkaline and Organosolv Treatment: Characterization and Optimization of Lignin Yield and Purity<\/b><\/a><\/p>\r\n

Mai Syadiah Khidzir, Siti Musliha Mat Ghani, Abdul Rahman Abdul Rahim & Khairirahanna Johari<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Effective coconut pith lignin (CPL) extraction remained an obstacle since lignin must be removed without causing significant destruction of cellulose fibers. This work seeks to solve these challenges by improving the extraction procedure for CPL to generate a material appropriate for industrial uses, such as anti-corrosion coatings, that take advantage of lignin\u2019s distinct features. A comprehensive technique based on response surface methodology (RSM) and central composite design (CCD) was used to optimize three critical process parameters: temperature, solvent concentration and time of alkaline treatment (AT) and organosolv treatment (OT) concentration for extracting the lignin. The screening findings showed that the AT produced the highest yield of lignin and purity compared to the OT. This will provide 72.29% CPL-AT and 86.00% purity through RSM analysis. (TGA) and (FTIR) were used to assess the physical qualities of lignin. Fourier transform infrared (FTIR) analysis demonstrated that CPL-AT and CPLOT possess similar spectrums, though the CPL-OT showed more prominent peaks of aromatic rings and phenolic hydroxyl groups. Thermogravimetric analysis (TGA) studies demonstrated that CPL-AT has higher heat stability owing to its higher molecular weight and solubility properties which makes it has potential and economically viable material for industrial applications such as bio-composite materials.<\/p>\r\n

Coconut pith; extraction; lignin; purity; yield<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-10\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2203-2220<\/span>\r\n <\/td>\r\n <\/tr>\r\n
11.<\/td>\r\n \r\n \r\n


Transformer Fault Classification Based on Dissolved Gas Compositions Using Microsoft Azure Machine Learning<\/b><\/a><\/p>\r\n

Chee Ying Chan*, Salmey Abdul Halim, Nursyarizal Mohd Nor & Nor Zaihar Yahaya<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This study presents a novel diagnostic methodology for oil-filled transformers, leveraging dissolved gas analysis (DGA) and a no-code machine learning framework. Conventional diagnostic methods such as Duval Triangle and gas ratio techniques are constrained by limited adaptability to modern transformer designs, susceptibility to misdiagnosis, and reliance on expert interpretation. Meanwhile, artificial intelligence (AI) approaches often demand significant programming expertise, large datasets, and computational resources. To address these challenges, the research introduced a unified machine learning model developed using Microsoft Azure Machine Learning, enabling field engineers to build and deploy diagnostic models without coding. The model utilized concentrations of 5 key gases: methane, ethylene, acetylene, ethane, and hydrogen, as input features to classify transformer conditions into 6 fault classes, including a no-fault state. 3 algorithms, namely Gradient Boosting, Random Forest, and Logistic Regression were evaluated, with Gradient Boosting consistently outperforming other models and Duval Triangle, achieving the highest accuracy of 81.3% with 2 false negatives. When the output labels were consolidated to 4 fault types, diagnostic accuracy improved to 95.6% without any false negative. Model performance was optimized through experiments involving train-test ratio variation and feature scaling. The model was further validated through field trials on actual transformers, demonstrating high reliability and alignment with forensic findings. This no-code approach empowers engineers to integrate domain expertise directly into model development, enhancing diagnostic precision and operational efficiency. The findings support scalable, interpretable, and proactive maintenance strategies, contributing to resilient infrastructure and sustainable energy systems.<\/p>\r\n

Classification; dissolved gas; fault diagnosis; machine learning; transformer<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-11\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2221-2238<\/span>\r\n <\/td>\r\n <\/tr>\r\n
12.<\/td>\r\n \r\n \r\n


High-Performance Titanium Composites: Mechanical and Metallurgical Characterization of Powder Metallurgy-Synthesized Materials<\/b><\/a><\/p>\r\n

Yonaf Wakuma, Devendra Kumar Sinha, Abdulrahman Aljabri, Asad A. Zaidi, Gaurav Gupta, Muhammad Asif, Gulam Mohammed Sayeed Ahmed & Sohaib Z. Khan<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Titanium metal matrix composites (Ti-MMCs) are advanced materials that offer superior mechanical properties, corrosion resistance, and structural integrity, making them well-suited for high-performance applications. This study investigates the effect of reinforcement particle composition on the mechanical and metallurgical properties of Ti-MMCs. Titanium Grade 5 (Ti-6Al-4V) powder was used as the matrix material, while cerium oxide (CeO2<\/sub>), chromium (Cr), and graphite (Gr) were employed as reinforcements. The composites were synthesized through powder metallurgy, which involved ball milling, hydraulic compaction, and high-temperature sintering. The synthesized composites were analyzed for phase composition and microstructure using X-ray diffraction (XRD) and optical microscopy. Hardness was assessed using a Vickers hardness tester, while compressive strength was evaluated through a universal testing machine. Corrosion resistance was examined via potentiodynamic polarization testing. Among the fabricated samples, Ti-6Al-4V composite reinforced with 5% CeO2<\/sub>, 10% Cr, and 4% Gr demonstrated the lowest porosity (4.37%) and the highest relative density (95%), indicating effective densification. This composition also exhibited superior mechanical properties, with a hardness of 682 HV and a compressive strength of 914 MPa. Furthermore, it provided corrosion resistance by achieving a protection efficiency of 76% and a corrosion current of 19.27 mA\/cm\u00b2, compared to pure Ti-6Al-4V. FT-IR analysis confirmed the presence of Ti-6Al-4V\u2013O bonding and the absence of hydroxyl absorption bands, indicating enhanced corrosion resistance. These findings highlight the potential of Ti-MMCs for biomedical applications, particularly in orthopedic implants requiring high strength, durability, and corrosion resistance. The study demonstrated that hybrid reinforcement tailoring is a viable strategy for engineering multifunctional Ti-based composites.<\/p>\r\n

Powder metallurgy; titanium metal matrix composites; vickers hardness; SEM; Corrosion<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-12\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2239-2251<\/span>\r\n <\/td>\r\n <\/tr>\r\n
13.<\/td>\r\n \r\n \r\n


Enhancing Labour Utilization in Semiconductor Manufacturing Through Maynard Operation Sequence Technique (MOST): A Case Study<\/b><\/a><\/p>\r\n

Wan Hasrulnizzam Wan Mahmood*, Mohd Nizam Ab Rahman, Abdurrahman Faris Indriya Himawan & Roslan Awang<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This study investigates the application of the Maynard Operation Sequence Technique (MOST) as a work measurement tool to analyze and improve labour utilization in a high-volume semiconductor manufacturing facility. The research focuses on the End-of-Line (EOL) inspection processes for Quad Flatpack No-Lead (QFN) products, which combine manual and semi-automated operations. Through detailed process mapping, operator activities were observed over full shifts, and sequences were analysed using MOST to establish standard times, assess utilization, and identify inefficiencies. Findings revealed notable variations in task execution among operators, with non-value-added activities such as excessive walking distances, manual documentation, and inconsistent methods contributing to low utilization rates. The average utilization was 13-16% per lot and 41-48% for three lots. The structured steps in the MOST predetermined time study demonstrate that production team members are able to systematically identify the most efficient process steps while eliminating non-value-added activities on the production line. The MOST analysis was able to offer targeted improvement initiatives regarding process standardization, unnecessary motion reduction, layout improvements, and the adoption of systems for digital documentation. These recommendations, if implemented, will also improve the man-to-machine ratio as, optimize workforce deployment, and reduce operating costs without compromising the quality of the product. This also goes on to show that the MOST analysis is effective in measuring time and productivity of the gap analysis in the semiconductor industry and is also relevant to other sectors that are looking for a structured, precise, and pragmatic approach to operational excellence.<\/p>\r\n

Maynard Operation Sequence Technique (MOST); work measurement; labour utilization; semiconductor manufacturing; productivity improvement<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-13\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2253-2261<\/span>\r\n <\/td>\r\n <\/tr>\r\n
14.<\/td>\r\n \r\n \r\n


Investigation of a Renewable Energy System Using HVAC Condenser Fans for Low-Power Surveillance Systems<\/b><\/a><\/p>\r\n

Damyrel Haqimi Zorba, Nor Aira Zambri*, Farahiyah Mustafa, Norhafiz Salim & Mohamad Aiman Arif Abu Bakar<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This study presents an innovative approach to sustainable energy generation by integrating energy harvesting mechanisms into outdoor air conditioning units. The proposed system employs miniature generators embedded within the fan assembly to capture mechanical energy produced during operation. A pulley-driven transmission system converts this mechanical energy into electrical power, which is stored in a rechargeable battery and subsequently used to power Closed-Circuit Television (CCTV) systems. To regulate and optimize the electrical output, the system incorporates a DC-DC buck converter to adjust voltage to a usable range, and a solar charge controller to monitor current and voltage during the charging process. The prototype was implemented on a 1-horsepower outdoor air conditioning unit, with operational testing conducted under typical usage conditions to evaluate system behaviour and ensure performance reliability with two types of testing conducted. The first involved evaluating different pulley ratios. Results show higher pulley ratios produced higher power output both before and after DC-DC conversion, indicating improved mechanical-to-electrical efficiency. The second test examined system performance under two ambient conditions, 24\u00b0C during nighttime and 30\u00b0C during daytime. Results indicate that the battery reaches a full state of charge more rapidly at 30\u00b0C compared to 24\u00b0C, primarily due to the longer duty cycle and extended operation of the condenser fan under higher thermal load. The system successfully powered the 5W CCTV unit without relying on grid electricity, demonstrating its feasibility as a renewable and environmentally friendly energy solution for residential and commercial infrastructure.<\/p>\r\n

Sustainable energy harvesting, air conditioning unit, CCTV system, renewable energy prototype, off-grid power supply<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-14\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2263-2276<\/span>\r\n <\/td>\r\n <\/tr>\r\n
15.<\/td>\r\n \r\n \r\n


Influence of c-CFRP Plate Length Variation on the Performance of Plain Concrete Beams under Four-Point Bending Test<\/b><\/a><\/p>\r\n

Zaim Omar*, Swathika Murugesan, Sugiman Sugiman, Dianah Mazlan & Hilton Ahmad<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The use of externally bonded carbon fibre-reinforced polymer (CFRP) plates for flexural strengthening of concrete beams has been well established; however, limited studies have explicitly focused on co-cured CFRP (cCFRP) plates applied to plain concrete beams without internal reinforcement. Crack control and interface bonding become critical in such systems, yet the optimal c-CFRP plate length for effective stress transfer and energy absorption remains unclear. This study addresses this gap using a four-point bending test setup to investigate the flexural behaviour of plain concrete beams strengthened with two-layer c-CFRP plates of varying lengths (100 mm to 250 mm). The results show that increasing the plate length improves ultimate load, energy absorption, and deflection capacity. The 200 mm c-CFRP length achieved the most balanced performance, reaching an ultimate load of 15.61 kN and an energy absorption of 21.66 kN\u00b7mm. The 250 mm plate provided the highest overall capacity (18.94 kN) but exhibited signs of controlled delamination. In contrast, shorter plates led to shear cracks at the plate tip due to inadequate anchorage. These findings highlight the critical role of plate length in governing failure modes and stress distribution, offering practical guidance for optimising c-CFRP retrofit strategies. Future studies are recommended to investigate bond quality, multi-layer configurations, and environmental durability for long-term applications.<\/p>\r\n

Carbon fibre; polymer matrix composites (PMCs); stress concentration; flexural strengthened; joints\/ joining<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-15\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2277-2290<\/span>\r\n <\/td>\r\n <\/tr>\r\n
16.<\/td>\r\n \r\n \r\n


Pendekatan Penjelmaan Anak-Gelombang untuk Penentuan Fasa Kritikal Gelombang Seismik daripada Gempa Ranau Mw 6.0<\/b><\/a><\/p>\r\n

Wavelet Transformation Approach for Determining the Critical Phase of Seismic Waves from the Ranau Mw 6.0 Earthquake<\/em><\/b><\/a><\/p>\r\n

Noor Sheena Herayani Harith*, Shahrum Abdullah & Nicole Myrel Juventinus<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This study presents a parametric analysis of seismic wave energy from the Mw 6.0 earthquake that struck Ranau, Sabah in 2015. The event was recorded by five seismic stations, with the nearest station in Kota Kinabalu, located 42.15 km from the epicentre. Seismic signals from this station recorded a peak ground acceleration of 0.124038 m\/s\u00b2. The wavelet transform signal processing approach was employed to analyse the time series signals in terms of acceleration, velocity and displacement. The signals were divided into seven segments (20%\u201380%) and analysed using the data from statistical parameters. Results reveal that the initial 30% segment contains the highest energy, with maximum acceleration and velocity values of 0.124038 m\/s\u00b2 and 0.0507350522 m\/s, respectively. The highest displacement value of 0.0050926746 m was observed in the 40% segment. The statistical parameters peaked in the 30\u201340% segment, indicating the presence of high energy waves. It has been shown that a dense distribution of the wavelet coefficients in the early segment, indicating a rapid and intense energy release, consistent with potential early P-wave detection. Meanwhile, the 40% segment reflects prolonged ground movement, suggesting delayed effects of the main wave. This study offers valuable insights into the dynamic behaviour of seismic waves and aids in identifying critical phases that pose higher risks to structural integrity. This study significantly contributes to the in-depth understanding of seismic wave dynamics by providing structured and comprehensive data.<\/p>\r\n

Ranau earthquake; seismic signal; wavelet; time segmentation; displacement<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-16\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2291-2305<\/span>\r\n <\/td>\r\n <\/tr>\r\n
17.<\/td>\r\n \r\n \r\n


Solvent Debinding of Cu-Al-Ni Shape Memory Alloy Micro-Components Produced by Micro-Powder Injection Molding<\/b><\/a><\/p>\r\n

Al Basir*, Norhamidi Muhamad, Abu Bakar Sulong, Kambiz Rashidi, Farhana Mohd Foudzi, Nabilah Afiqah Mohd Radzuan & Nashrah Hani Jamadon<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The escalating demand for the high-volume manufacturing of precisely detailed and small-scale parts has become increasingly pronounced over the past few years. In this context, micro-powder injection molding (\u00b5PIM), an advanced adaptation of the powder injection molding (PIM) technique, has proven to be a cost-effective and technically sophisticated method for the precise shaping and mass production of micro-scale metallic and ceramic parts. \u00b5PIM is a potentially efficacious process for the fabrication of micro-sized Cu-Al-Ni shape memory alloy (SMA) components. However, debinding remains challenging for micro-sized components, regardless of materials, because of their tendency toward cracking and dimensional distortion. This study involved the formulation of a 68 vol. % powder-loaded Cu-Al-Ni feedstock through the mixing of a Cu-Al-Ni powder mixture with a binder system, composed of paraffin wax (PW), high-density polyethylene (HDPE), and stearic acid (SA), at an elevated temperature of 150\u00b0C maintained for 1 hour period to ensure feedstock homogeneity. Green micro-components of Cu-Al-Ni SMA were produced through micro-injection molding by employing controlled process conditions comprising an injection pressure of 10 bar, an injection duration of 6 s, a mold temperature of 145\u00b0C, and a melt temperature of 180 \u00b0C. Following a solvent debinding procedure at 60\u00b0C for 1 hour, 74.4% of the PW and SA soluble binders were effectively removed from the green micro-component without inducing any defects or cracking in the component. The open channels formed in the solvent debound parts assist in the expulsion of the HDPE binder through thermal debinding phase.<\/p>\r\n

Shape memory alloy; Micro-powder injection molding; Cu-Al-Ni; Binder; Debinding<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-17\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2307-2315<\/span>\r\n <\/td>\r\n <\/tr>\r\n
18.<\/td>\r\n \r\n \r\n


Pemodelan Berangka Cerun Tanah Tak Tepu Bukit Mewah Menggunakan Data Lapangan Lengkung Ciri Air-Tanah<\/b><\/a><\/p>\r\n

Numerical Modeling of Unsaturated Soil Slope of Bukit Mewah Using Field Data of Soil-Water Characteristic Curves<\/em><\/b><\/a><\/p>\r\n

Faris Shazani Suhaizan, Aizat Mohd Taib* & Mohd Raihan Taha<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Rainfall-induced instability is a major concern for unsaturated residual soil slopes in tropical regions, where porewater pressure and matric suction fluctuate rapidly under transient hydrological conditions. This study investigates the hydro-mechanical response of the Bukit Mewah slope in Selangor through a fully coupled flow\u2013deformation analysis using PLAXIS 2D. Bukit Mewah slope represents a typical urban residual soil slope in a tropical environment and is located within a residential area, making it suitable for slope investigation. The numerical model incorporates sitespecific soil-water characteristic curves (SWCCs) derived from field monitoring data, allowing a realistic representation of unsaturated hydraulic behaviour. The simulation reproduced the pore-water-pressure dynamics at the monitored depths of 0.5 m and 1.0 m. At 0.5 m depth, suction during dry periods decreased to approximately \u20137.5 kPa, while heavy rainfall caused rapid dissipation toward about 5 kPa. At 1.0 m depth, pore-water pressure reduced to around \u201312 kPa after minor rainfall and rose to a peak of approximately 9 kPa during the heaviest storm. These responses aligned closely with the field sensor data, confirming the model\u2019s ability to capture wetting-front progression, delayed deeper infiltration, and post-rainfall suction recovery. The Factor of Safety (FoS) remained relatively stable, slowly increasing from 1.35 to 1.55, but dropped sharply to about 0.9 during the first major rainfall event. A second reduction to approximately 1.07 from 1.40 occurred during the subsequent heavy storm, followed by gradual recovery as suction redeveloped. Overall, the results demonstrate that PLAXIS 2D effectively reproduces the coupled hydraulic\u2013mechanical behaviour of an unsaturated tropical slope, providing valuable insights into rainfall-induced pore-pressure changes and stability fluctuations.<\/p>\r\n

Pore-water pressure; PLAXIS; unsaturated; factor of safety<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-18\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2317-2328<\/span>\r\n <\/td>\r\n <\/tr>\r\n
19.<\/td>\r\n \r\n \r\n


Fatigue Reliability Analysis of In-Service Pipelines using Fuzzy-Weibull approach to Reduce Epistemic and Aleatory Uncertainty in Stochastic Stress Loads<\/b><\/a><\/p>\r\n

Muhammad Ali Khan, Salvinder Singh Karam Singh*, Shahrum Abdullah, Azli Arifin, M. Zaid Kamardin & Musa Bashir<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This paper integrates fuzzy logic with the Weibull distribution to improve fatigue reliability predictions for offshore steel pipelines under both aleatory and epistemic uncertainties. The existing durability assessments techniques mainly rely on deterministic material properties and simplified loading assumptions, which fail to account for epistemic uncertainty arising from limited data, corrosion-induced degradation, and operational variability. This study addresses that gap by incorporating stochastic modelling and epistemic uncertainties through realistic representations of material degradation and cyclic load variability. Stochastic modelling combined five years of in-service load data with experimental material properties, capturing degradation effects of corrosion on the API X65 Pipeline Steel material. Fuzzy logic quantified the epistemic uncertainty in Weibull parameters through low, medium, and high membership functions. The experimental results showed the yield strength variability (594 ~ 366 MPa) due to effects of corrosion and welding created an interference region, reducing structural integrity under random loading. The Fuzzy-Weibull Fatigue reliability assessment results showed mean cycles to failure ranging from 1.03 x 109<\/sup> for operational stresses to 5.48 105<\/sup> for interference region, with correlation of 90 % to the experimental S-N curve. Defuzzified reliability rose from 0.38 to 0.46, while the fatigue reliability index increased from 2.1 to 5.3 under operational stresses but declined from \u20130.6 to \u20132.25 in the interference region with the increase in Weibull shape parameter. Overall, the proposed method strengthens pipeline durability assessment by incorporating both random variability and epistemic uncertainty.<\/p>\r\n

Durability assessment; fatigue reliability; Fuzzy Logic; Weibull Distribution<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-19\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2329-2345<\/span>\r\n <\/td>\r\n <\/tr>\r\n
20.<\/td>\r\n \r\n \r\n


Techniques for Dimple Surface Modification and Tribology Performance: A Systematic Review<\/b><\/a><\/p>\r\n

Mohd Shahir Kasim*, Jaharah Abd Ghani, Siti Nurul Akmal Yusof, Norliana Yusof, Roslan Awang, Amin Omar, Armansyah Ginting & Afifah Zakiyyah Juri<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This paper systematically reviewed and evaluated the existing literature on dimple profile modification methods and parameters to enhance surface tribology in various engineering applications. A comprehensive search was conducted using Scopus, ASME, and Mendeley databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard. The search focused on publications from 2021 to 2024, yielding 1635 related articles, of which 66 were shortlisted for full review based on inclusion criteria. These studies were categorized into four primary themes: Dimple Profile Application, Dimple Profile Modification Techniques, Tribological Performance Enhancement, and Future Trends in Dimple Profile Development. The review highlights the critical role of dimple profiles in reducing friction, improving lubrication, and enhancing wear resistance, which are pivotal for the reliability and efficiency of mechanical systems. A variety of techniques for dimple fabrication, such as laser texturing, through-mask electrochemical machining (TMECM), and electrical discharge machining, were analyzed, showcasing their respective advantages and limitations. Furthermore, the influence of parameters such as dimple shape, size, depth, and density on tribological performance was thoroughly examined. The findings contribute to a deeper understanding of the interplay between surface topography and tribology, offering insights into optimizing dimple profiles for specific applications. The review also identifies existing challenges and outlines future research directions to advance surface engineering solutions in tribological systems.<\/p>\r\n

Surface tribology; dimple profiles; friction; systematic review; PRISMA<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-20\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2347-2360<\/span>\r\n <\/td>\r\n <\/tr>\r\n
21.<\/td>\r\n \r\n \r\n


Optimizing Resource Allocation using Simulation-Optimization Approach at Private Specialist Centre<\/b><\/a><\/p>\r\n

Nurul Wadina Amran, Ireen Munira Ibrahim*, Faridah Zulkipli, Siti Rozanae Ismail & Zulkifli Mohd Nopiah<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Long waiting times refer to the prolonged length of time patients spend waiting for medical treatment. This is due to a lack of human resources or equipments such as doctors, nurses or treatment rooms. This study investigates the optimization of resources allocation in private specialist centre to address long waiting times and enhance operational efficiency. A simulation model was developed by using Discrete Event Simulation (DES) approach to represent the actual patient flow in the centre and identify system bottlenecks that contributed to the prolonged waiting times. To determine the most effective resource configuration, the DES model was optimized using the Simulation-Optimization capabilities of OptQuest in Arena software. The optimization process focused on minimizing the Total Average Waiting Time (TAWT) while adhering to operational constraints such as limited staff and equipment. The results significantly improved the Total Average Waiting Time (TAWT) by 52.74%, reduction from 234.26 minutes to 110.71 minutes. This finding highlights the effectiveness of Simulation-Optimization approach in healthcare resource planning and offers valuable insights for optimizing operations in private specialist centres as well as reducing the congestion.<\/p>\r\n

Discrete event simulation; linear programming; resources allocation<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-21\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2361-2371<\/span>\r\n <\/td>\r\n <\/tr>\r\n
22.<\/td>\r\n \r\n \r\n


Influence of Bitumen Chemistry and Crumb Rubber Pre-Treatment on the Storage Stability and Rheological Performance of Modified Binders<\/b><\/a><\/p>\r\n

Naeem Aziz Memon*, Nur Izzi Md. Yusoff, Ahmed Suliman B. Ali, Warid Wazien, Aawag Mohsen Alawag, Zubair Ahmed Memon & Shabir Hussain Khahro<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The incorporation of crumb rubber (CR) into bitumen offers significant performance and sustainability advantages, yet its widespread adoption is impeded by poor storage stability caused by thermodynamic incompatibility. To address this fundamental challenge, this study investigates the role of bitumen chemistry, specifically the balance of fractions determined via SARA analysis, and the efficacy of crumb rubber pre-treatment in creating a stable binder system. Two base bitumen with distinct chemical compositions (PG 58-28 and PG 70-22) were modified with 10% and 15% CR, comparing two distinct modification philosophies: a palliative approach using styrene-butadienestyrene (SBS) and a fundamental approach employing devulcanized CR : a conventional stabilization approach using low dosages of styrene-butadiene-styrene (SBS) (1-3%) with untreated CR, and employing pre-treated, devulcanized CR without SBS. Binder performance was thoroughly investigated using storage stability and the Multiple Stress Creep Recovery (MSCR) test. The SARA analysis revealed that the softer bitumen, possessing a higher maltene-toasphaltene ratio, provided a superior solvent medium for polymer swelling. Despite this, all untreated CRMB blends exhibited severe phase separation (\u0394SP>7\u00b0C), and the addition of SBS at 1-3% dosages proved insufficient to achieve stability, failing to meet the standard specification criterion (\u0394SP\u22642.5\u00b0C). In contrast, pre-treatment of the CR via thermo-mechanical devulcanization resulted in inherently stable blends (\u0394SP<2.5\u00b0C) across both bitumen grades, even without the addition of any stabilizing co-polymer. Furthermore, the devulcanized CRMB demonstrated superior rheological performance, achieving an \u201cExtreme\u201d traffic rating (Jnr3.2<0.5 kPa\u22121) with excellent elastic recovery. Statistical analysis confirmed that the modification strategy is the most significant factor influencing both stability and performance. The findings demonstrate that at the investigated dosages (1\u20133%), SBS is an inadequate palliative for stabilizing untreated CRMB, establishing CR pre-treatment via devulcanization as a more effective and fundamental engineering solution.<\/p>\r\n

Crumb Rubber Modified Bitumen (CRMB); storage stability; Styrene-Butadiene-Styrene (SBS); SARA Analysis; Multiple Stress Creep Recovery (MSCR); devulcanized rubber<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-22\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2373-2382<\/span>\r\n <\/td>\r\n <\/tr>\r\n
23.<\/td>\r\n \r\n \r\n


Simulation-Based Structural Optimization of FBG-Integrated Stud Bolts for Real-Time Stress Monitoring in Flange Joints<\/b><\/a><\/p>\r\n

Muhammad Abdullah, Mohd Hafizi Zohari* & Ahmad Alias<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

In critical sectors such as oil and gas, more than 90% of bolted joint failures result from improper preload during installation. Loss of bolt tension can cause flange leakage, leading to environmental damage or fire hazards. This study aims to improve the performance of a modified M18 stud bolt integrated with Fiber Bragg Grating (FBG) sensors to reduce structural damage while enabling accurate real-time stress\u2013strain monitoring. Finite Element Analysis (FEA) was conducted using ANSYS. Five bolt designs were evaluated under an applied torque of 70 Nm. The models varied in groove position to accommodate FBG sensor placement. Stress and strain responses were analyzed using a mesh size of 0.15 mm. The top groove extending to the flange end produced 2877.90 \u00b5\u03b5 strain but generated a maximum von mises stress of 582 MPa, approaching nearly the 640 MPa yield strength of Grade 8.8 steel. The centre groove extending to the flange end exceeded both 3000 \u00b5\u03b5 strain and the yield limit, indicating structural instability. In contrast, the top groove extending to the bolt end achieved 1639.5 \u00b5\u03b5 strain while maintaining a lower maximum stress of 323.04 MPa, well within the elastic range. Based on mechanical response and manufacturability considerations, the top groove till end configuration provides the most consistent balance between strain response and structural safety. The numerical results demonstrate that controlled groove placement enables strain sensing while preserving elastic behavior in bolted flange systems. The simulation confirms that this approach improves the safety of bolted flange systems and enables reliable real-time monitoring.<\/p>\r\n

FBG sensors; stud bolts health monitoring; strain transfer efficiency; sustainable flange joint integrity; bolt pre-load monitoring<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-23\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2383-2393<\/span>\r\n <\/td>\r\n <\/tr>\r\n
24.<\/td>\r\n \r\n \r\n


An Edge\u2013Cloud Integrated Smart Monitoring System for Sustainable Freshwater Fishpond Management<\/b><\/a><\/p>\r\n

Mohamad Fikri Aiman Hanif & Mohammad Ali Sarvghadi*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Water quality is a critical determinant of fish health and productivity in freshwater aquaculture, with parameters such as pH, dissolved oxygen (DO), temperature, and turbidity directly influencing growth, metabolism, and disease susceptibility. Traditional monitoring methods, based on manual sampling and laboratory analysis, are often slow, labor-intensive, and unable to detect rapid environmental changes. This paper presents the design and implementation of a hybrid edge\u2013cloud integrated smart monitoring system for sustainable freshwater fishpond management. The system employs an ESP32-based edge node to collect real-time water quality data, detect threshold violations locally, and trigger immediate responses, including LED\/buzzer alarms and actuator activation, while simultaneously sending email alerts via SMTP. Long-term data storage, visualization, and remote access are enabled through a cloud platform integrated with MQTT-based data publishing. Experimental evaluation demonstrated a total detection-to-action latency of 3.4 s, local alerts in 1.0 s, email notifications within 7.0 s, and cloud synchronization latency of 150 ms. Sensor measurements achieved high accuracy, with maximum deviations of only \u00b10.11 pH units, 0.3 mg\/L DO, 0.21 NTU turbidity, and 0.2\u00b0C temperature. The system maintained 100% uptime during stable network conditions, confirming its reliability for continuous aquaculture monitoring. By combining low-latency local decision-making with cloud-based analytics, the proposed solution enhances operational efficiency, supports proactive management, and aligns with SDG 6 (Clean Water and Sanitation) and SDG 14 (Life Below Water). Future work will focus on integrating machine learning models for predictive water quality analysis and expanding the platform to other aquaculture and smart farming applications.<\/p>\r\n

Water quality; water monitoring; cloud computing; edge computing<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-24\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2395-2410<\/span>\r\n <\/td>\r\n <\/tr>\r\n
25.<\/td>\r\n \r\n \r\n


Statistical Evaluation of Moisture and Time Effects on the pH of Zingiber zerumbet<\/i> Extracts by Subcritical Water Extraction<\/b><\/a><\/p>\r\n

Nurul \u2018Uyun Ahmad*, Mariam Firdhaus Mad Nordin, Norrashidah Mokhtar, lzzati Mohamad Abdul Wahab, Muhamad Ali Muhammad Yuzir, Tan Ka Liong & Mardawani Mohamad<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Zingiber zerumbet is a medicinally important rhizome, with subcritical water extraction (SWE) offering a sustainable approach to recover its bioactive compounds. However, the influence of raw material moisture and process parameters on extract quality remains unclear. This study investigates two factors which affect the pH of Z. zerumbet extracts produced via SWE; (i) its initial rhizome moisture content (MC), (ii) the extraction time. Fresh rhizomes were extracted at subcritical condition for 5 - 25 min. MC and pH were measured, and statistical analyses were performed using General Linear Model (GLM) and Multiple Linear Regression (MLR). All extracts were slightly acidic (pH 5.85 \u00b1 0.03 \u2013 6.24 \u00b1 0.02). GLM showed that extraction time significantly impacted pH (F(4,9) = 55.92, p < 0.001, partial \u03b7\u00b2 = 0.961). The final multivariate model explained 98.3% of the pH variance (Adjusted R2=0.973), but the MC which shown explanatory bivariate association with pH was non-significant after controlling extraction time (p=0.129). Visual observations indicated stable, homogeneous extracts, with only darkening at longer extraction times. Overall, extraction time is the dominant factor influencing acidity of Z. zerumbet extracts under SWE, while initial moisture exerts only minor and inconsistent effects. These findings underscore the importance of controlling extraction duration for process optimization and product reproducibility, with moisture monitoring serving as a secondary safeguard. Future studies should expand on other SWE parameters and predictive validation to strengthen industrial applicability.<\/p>\r\n

Zingiber zerumbet; subcritical water extraction; moisture content; extraction time; pH value<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-25\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2411-2421<\/span>\r\n <\/td>\r\n <\/tr>\r\n
26.<\/td>\r\n \r\n \r\n


Geometrical and Mechanical Characterization of JSC1180YN Ultra-High Strength Steel Tailored Blanks Produced by Successive Forging<\/b><\/a><\/p>\r\n

Kwong Wei Jun, Liyana Tajul Lile, Roshaliza Hamidon, Mohd Hafis Sulaiman, Witthaya Daodon & Hasnulhadi Jaafar*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Successive forging is a multi-stage process for tailoring ultra-high strength steel (UHSS) sheets thickness which is normally done using rolling or welding process. These two processes often have problems of long transition zone and degradation of mechanical properties. This study investigates the geometrical change and deformation at the transition zone after successive forging process. A 1.6 mm thick JSC1180YN UHSS sheet was subjected to successive forging process using a 1500-kN servo press and an automatic feeder, aiming to achieve a thickness reduction of 0.8 mm. 20 forging steps were set with a constant feed rate of 5 mm. The punch was designed with 1 mm chamfered edges to promote uniform strain distribution, while the lower die is set to be flat. The results showed that the thickness reduction to 0.8 mm was maintained within \u00b10.1 mm, with an increase of 0.84% in width and 8.1% in length. The geometric control was followed by an improvement in mechanical properties, where there was an increase in Vickers hardness from 415 HV to 442 HV. Tensile testing showed an increase in ultimate tensile strength of 37.5%, while a reduction in ductility was observed due to strain hardening. The tailor forged blanks maintained a high structural integrity. Successive forging can shorten the transition zone length with minimal impact on shape changes. Overall, successive forging proves to be a process that can effectively modify the geometry and mechanical performance, providing an alternative to automotive applications.<\/p>\r\n

Ultra-High Strength Steel (UHSS); successive forging; tailored blanks; geometrical variation; transition zone<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-26\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2423-2434<\/span>\r\n <\/td>\r\n <\/tr>\r\n
27.<\/td>\r\n \r\n \r\n


Plasma Arc Assisted Additive Manufacturing Using Magnesium Alloys: A Review<\/b><\/a><\/p>\r\n

Walisijiang Tayier* & Shamini Janasekaran*<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Magnesium alloys have emerged as essential materials in biomedical applications due to their biocompatibility and biodegradability. However, the complex geometries and specialized qualities required for sophisticated implants are beyond the reach of traditional manufacturing methods. To overcome these issues, this work explores a novel additive manufacturing (AM) technique called plasma arc-based hybrid heating (arc fusion and laser-based). By leveraging the synergistic effects of plasma and hybrid energy, it enables precise control over extreme processing temperatures, facilitating the fabrication of magnesium alloys with optimized microstructures and enhanced mechanical performance. This research systematically examines the relationship between plasma-driven thermal dynamics, grain refinement mechanisms, and resultant mechanical properties, including tensile strength and fatigue resistance. Furthermore, the study highlights the role of rapid solidification in minimizing defects such as porosity and residual stresses, which are critical factors for implant longevity. These findings underscore the transformative potential of plasma technology in advancing the production of patient-specific biomedical devices, offering a pathway to high-performance, custom-designed magnesium implants. This work not only bridges existing gaps in the additive manufacturing of bio-compatible metals but also establishes a foundation for future innovations in sustainable medical solutions.<\/p>\r\n

Plasma; hybrid heating; microstructure; sustainable manufacturing; magnesium alloys<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-27\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2435-2455<\/span>\r\n <\/td>\r\n <\/tr>\r\n
28.<\/td>\r\n \r\n \r\n


From Paper to Pixels: Improving RF Productivity with Digital Check Sheets and DMAIC<\/b><\/a><\/p>\r\n

Nazreen Raveenthiran, Nursakirah Ab Rahman Muton*, Nor Athiyah Abdullah & Rasslenda-Rass Rasalingam<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Manufacturing documentation often contributes to process inefficiencies, human error, and productivity constraints within the RF brazing workflow. This study aimed to improve manufacturing documentation at NGK Electronics Devices by replacing manual check sheets with a digital RF Brazing Checksheet System. Guided by the Lean Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) framework, the study adopted a mixedmethods approach involving observation, time tracking, and user feedback to evaluate the existing process. The main issues identified included lengthy documentation, inaccurate data entry, limited traceability, and inefficient retrieval of historical records. A digital check sheet incorporating autofill, field validation, and expiry alerts was subsequently developed and piloted over four weeks. Following implementation, form completion time decreased by more than 60%, error rates fell by over 80%, and technician workload was reduced. In addition, integrating real-time dashboards and feedback loops strengthened continuous improvement in line with Kaizen principles. The success of the system has prompted plans for broader deployment across additional product lines, including optical parts, as well as possible integration with digital work instructions (WORKI) to support fully paperless operations. The findings demonstrate that lean-driven digital transformation can modernize legacy documentation practices, improve data quality and accessibility, and enhance RF brazing throughput in manufacturing settings. This study also confirms the value of the DMAIC framework for designing, piloting, and sustaining digital interventions on the shop floor, resulting in measurable gains in accuracy, efficiency, and operator experience. Future work will evaluate cost savings, quality yield, and long-term sustainability metrics.<\/p>\r\n

Lean Six Sigma (LSS); Digital Transformation; Kaizen; Operational Excellence; DMAIC<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-28\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2457-2468<\/span>\r\n <\/td>\r\n <\/tr>\r\n
29.<\/td>\r\n \r\n \r\n


Linear Programming Approach for Feasible Workpiece Mounting Regions to Maximize Workspace Utilization in Spindle-Tilted Five-Axis CNC Milling Machines<\/b><\/a><\/p>\r\n

Aqeel Ahmed*, Asim Zaheer, Maqsood Ahmed Khan & Muhammad Wasif<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Maximum utilization of the workspace of five-axis CNC machines is a difficult task. Maximum utilization means machining a larger part on a smaller CNC machine by using optimized setup parameters of the workpiece on the machine table. Determination of these setup parameters is a core problem of this research. Currently, these setup parameters are selected randomly and simulation is done for the verification of the complete machining without overtravel of the machine translational axes. A spindle-tilting\/rotating five-axis CNC milling machine is chosen for its superior ability to machine larger parts. In this research, a method is developed for determining the feasible regions on the table, where part can be mounted. These feasible regions will give the guarantee of complete machining of a bigger part without over travel of machine translational axes. By bounding the translational axis movements determined by the postprocessing equations with the limits set by the manufacturer, a linear programming model can be developed and solved for the feasible regions for mounting the workpiece on the table. Validation of the valid setup parameters determined by the proposed method is done in virtual machining environment. Through this method, it is easy to determine whether all machining features can be completed in one setup or if multiple setups are required. It also identifies the minimum number of setups, significantly reducing the workpiece setup time.<\/p>\r\n

Spindle-tilted\/rotating 5-axis CNC Machine; feasible setup parameters; linear programming<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-29\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2469-2481<\/span>\r\n <\/td>\r\n <\/tr>\r\n
30.<\/td>\r\n \r\n \r\n


Delamination Detection in Composites Using Acoustic Signal from Fiber Bragg Grating Sensor: A Comprehensive Review<\/b><\/a><\/p>\r\n

Amanina Farhana Ahmad, Mohd Hafizi Mohd Zohari* & Ihsan Naiman Ibrahim<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Delamination is an important failure mode of composite materials and can cause structural failure without visible signs. Early and reliable detection is crucial, especially in safety related sectors such as aerospace, automotive or wind energy. Fiber Bragg grating (FBG) sensors have gained widespread popularity for structural health monitoring (SHM), thanks to their high sensitivity, immunity to electromagnetic interference, compactness, and multiplexing ability. This paper reviews the use of FBG sensors for acoustic signal-based delamination detection. The paper categorizes sensor configurations (embedded, surface mounted, hybrid), methods for obtaining signals estimation and extracting features. Time Frequency analysis techniques, including Short Time Fourier Transform (STFT), wavelet transforms, and Fast Fourier Transfer (FFT) are discussed together with machine learning and deep leaning techniques such as support vector machines (SVM), Convolutional Neural Networks (CNNs), long short-term memory models. Their performance of detecting and categorizing delamination events is indeed critically scrutinized. Hybrid systems between FBG and acoustic emission (AE) or piezoelectric sensors are described as a result of their improved detectability. Recent advancements are also discussed including nano enhanced coatings that aid in increasing sensor sensitivity and environmental hardiness. Environmental effects, signal loss and sensor location problems and cost of the system are considered. The review wraps up with discussion on the significant limitations that need to be addressed and suggestions for future directions, such as adaptive signal processing, integration of AI and field ready interrogation units. The extensive evaluation presented here establishes the ground for further development of FBG based SHM methods into real time delamination inspection tools for composite structures.<\/p>\r\n

Delamination detection; composite materials; Fiber Bragg Grating (FBG); acoustic signal; structural health monitoring (SHM)<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-30\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2483-2501<\/span>\r\n <\/td>\r\n <\/tr>\r\n
31.<\/td>\r\n \r\n \r\n


A State of Art Review of Performance Evaluation of Solar Cooker with Thermal Energy Storage Materials<\/b><\/a><\/p>\r\n

Romil Patel*, Maulik Patel, Anil Patel, Amit Patel, Mehul Patel, Tejash Patel, Vishant Patel & Kalpesh Patel<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Solar cookers are an alternative to the traditional cooking systems; they are clean and sustainable; however, the practical use of solar cookers is still limited by the intermittency of the sun and the lack of sufficient amount of heat during the sunset. The lack of successful thermal energy storage (TES) implementation ends up in the lack of consistent cooking performance and lower reliability in domestic application. In dealing with this challenge, the current review critically reviews solar cookers that have sensible and latent heat storage materials to improve effectiveness, reliability, and off-sunshine cooking abilities. The aims of this review are to: (i) determine the performance of solar cookers that use sensible, latent and hybrid TES systems; (ii) analyse thermo-physical characteristics and applicability of widely used phase change material (PCM), e.g. acetanilide and stearic acid and binary salt mixtures; (iii) determine the effectiveness of sensible heat storage materials such as granite, sand and thermal oils; and (iv) determine critical advancements in technology, limitations and gaps in research associated with heat transfer enhancement, system integration and long-term stability. Research literature shows that the latent heat storage with the help of PCMs significantly increases the thermal retention that allows cooking several hours after dark and increases the efficiency of the entire cooker by about 20-40% in comparison with traditional solar cookers. Sensible storage of heat utilizes reliable short term heat availability of three to five hours, as compared to hybrid storage systems that combine high heat storage capabilities and predictable heat output. Overall, the combination of sensible and latent TES resources improves the work of the solar cookers and encourages the use of energy resources in the households in a more sustainable way. The research in the future ought to concentrate on high-end storage materials, cost-efficient designs, and scalable systems to enhance efficiency and acceptance by the users.<\/p>\r\n

Solar energy; energy storage; sensible heat; latent heat; solar cooker<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-31\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2503-2517<\/span>\r\n <\/td>\r\n <\/tr>\r\n
32.<\/td>\r\n \r\n \r\n


Integrasi Pembelajaran Mendalam YOLOv9m dan Penglihatan Komputer Klasik bagi Pengenalpastian Struktur Gelembung Plasma Khatulistiwa daripada Keogram ROTI<\/b><\/a><\/p>\r\n

Integration of YOLOv9m Deep Learning and Classical Computer Vision for Equatorial Plasma Bubble Structure Identification from ROTI Keograms<\/em><\/b><\/a><\/p>\r\n

Idahwati Sarudin*, Mohamad Haniff Junos*, Nurul Shazana Abdul Hamid, Mardina Abdullah & Logesh Kumar Selvakumar<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

The application of deep learning for identifying equatorial plasma bubbles (EPBs) from Rate of Total electron content Index (ROTI) keograms remains underexplored. This study presents a hybrid approach combining deep learning and classical computer vision to identify EPB structures in ROTI keograms. The proposed method employs the YOLOv9m model to detect EPBs in image data, generating bounding boxes around detected regions. A color filtering technique is then applied to remove background noise and exclude overlapping EPBs within a single detection, ensuring accurate isolation of the primary EPB. Post-detection analysis revealed instances of multiple components within single bounding boxes, with measured inter-component distances ranging from 9.22 to 148.82 pixels. Furthermore, identified EPBs exhibited varying drift speeds: EPB 1 showed near-fast motion (average displacement: 47.67 pixels\/30 min; lifespan: >300 minutes), EPB 2 displayed fast motion (58.00 pixels\/30 min; lifespan: >180 minutes), and EPB 3 demonstrated slow motion (30.80 pixels\/30 min; lifespan: >180 minutes). Building upon these initial detection and characterization results obtained from a 462-data training set, future work will focus on extensive analysis to quantitatively assess EPB characteristics using the presented deep learning model.<\/p>\r\n

Equatorial plasma bubbles; deep learning; YOLO; color detection<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-32\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2519-2531<\/span>\r\n <\/td>\r\n <\/tr>\r\n
33.<\/td>\r\n \r\n \r\n


Sistem Pintar Berasaskan Fotopletismografi dalam Telinga untuk Pengesanan Aritmia: Potensi Aplikasi dalam Eksplorasi Angkasa<\/b><\/a><\/p>\r\n

Smart In-Ear PPG-Based System for Arrhythmia Detection: Potential Applications in Space Exploration<\/em><\/b><\/a><\/p>\r\n

Khalida Azudin, Kok Beng Gan*, Rosmina Jaafar, Mahmoud Muhanad Fadhel, Wallace Wong Ming Yip, Kow Ping, Mohd Hasni Ja\u2019afar, Mohd Shawal Faizal Mohammad & Kok Swee Sim<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Space missions require reliable and safe physiological monitoring systems, as well as capable of continuous operation, as microgravity affects cardiovascular function and heart rhythm stability. This study develops and validates an intelligent in-ear photoplethysmography (PPG) system for continuous cardiac rhythm monitoring and real-time arrhythmia detection. A total of 2,926 PPG signal segments were collected, covering both normal and arrhythmic conditions. Signals were recorded at 75 Hz and upsampled to 256 Hz, then preprocessed using a 0.56 Hz Butterworth filter, artifact detection, and segmentation into 2,560 data points (\u224810 s). A hybrid ResNet\u2013LSTM\u2013Attention model was developed to extract morphological and temporal features, while performance was evaluated using 5-fold crossvalidation. The results demonstrated consistent and robust performance with accuracy 0.7138 \u00b1 0.1115, AUC 0.8078 \u00b1 0.0492, and F1-Score 0.7198 \u00b1 0.0788, confirming the model\u2019s capability to detect cardiac rhythm abnormalities from in-ear PPG signals. These findings highlight the potential of this technology as a continuous cardiovascular monitoring platform, suitable for integration into wearable devices and mobile health applications, as well as for use in extreme environments such as space, where conventional electrocardiography is less practical.<\/p>\r\n

Photoplethysmography; hearable; space mission; cardiovascular; arrhythmia<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-33\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2533-2545<\/span>\r\n <\/td>\r\n <\/tr>\r\n
34.<\/td>\r\n \r\n \r\n


Pembangunan dan Pencirian Bahan Meta Auxetik berinspirasikan Origami dengan Struktur Semanggi Berdaun Empat<\/b><\/a><\/p>\r\n

Development and Characterization of Origami-Inspired Auxetic Metamaterials with a Four-Leaf Clover Structure<\/em><\/b><\/a><\/p>\r\n

Nur Fatin Mohamad Razali, Norsuzlin Mohd Sahar*, Norbahiah Misran, Badariah Bais & Mohammad Tariqul Islam<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Auxetic metamaterials are characterized by their negative Poisson\u2019s ratio, which has attracted widespread attention due to their unique deformation behavior that offers advantages in energy absorption, impact resistance, and flexibility. However, conventional auxetic structures are limited by issues related to scalability and manufacturing challenges. Origami-inspired designs provide tunable mechanical properties through simple and foldable geometries. This study presents the design and mechanical characterization of an auxetic structure inspired by a four-leaf clover origami pattern. The origami-based design was selected for its ability to achieve tunable mechanical properties through foldable and repeatable geometrical configurations. The proposed structure was analyzed through finite element simulation and experimental testing. Finite element simulations were conducted using the finite element analysis software COMSOL Multiphysics to evaluate the deformation and stress responses under applied loading conditions. Experimental validation was carried out through uniaxial compression testing, where displacement measurements were used to determine the Poisson\u2019s ratio. The results demonstrated that the structure exhibited a pronounced auxetic response, with Poisson\u2019s ratio values ranging from \u22121.0 to \u22120.2. These findings confirm the effectiveness of the origami-inspired geometry in achieving auxetic properties. The simplicity and adaptability of the four-leaf clover pattern make it a promising candidate for future applications in flexible structures, biomedical devices, and protective systems.<\/p>\r\n

Auxetic; metamaterials; origami; negative Poisson\u2019s ratio<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-34\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2547-2557<\/span>\r\n <\/td>\r\n <\/tr>\r\n
35.<\/td>\r\n \r\n \r\n


Study on the Effect of Secondary Pouring Interval on Tensile and Flexural Strength of Concrete with Cold Joints<\/b><\/a><\/p>\r\n

Jun Wang, Kai Li*, Yamei Kong, Binhui Deng, Wenhui Qiu & Jingyun Liu<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

To enrich and refine the understanding of how secondary pouring intervals affect the mechanical properties of concrete with cold joints, building upon prior experimental studies examining the impact of cold joints on the mechanical properties of highly fluid C45 concrete, Abaqus software was employed to conduct finite element analysis on the splitting tensile strength and flexural strength of concrete with cold joints at multiple factor levels of secondary pouring time intervals ranging from 0.5T to 15T (where T represents the initial setting time of concrete). The results were compared with experimental data, showing consistent trends between finite element and experimental values, with errors within 10%. This demonstrates the applicability of the finite element model for analyzing the tensile and flexural properties of concrete with cold joints. Applying this model to explore the impact of cold joints on concrete mechanical properties at secondary pour intervals of 7-70d revealed that the effect diminishes and gradually stabilizes after 7 days. Compared to monolithic pouring, when secondary pouring occurred at 7d, 28d, 42d, and 56d, the splitting tensile strength decreased by 57.2%, 60.7%, 61.3%, and 61.9%, respectively, with reduction rates of 57.2%, 3.5%, 0.6%, and 0.6%. The flexural strength decreased by 59.9%, 67.6%, 68%, and 68.2%, respectively, with reduction rates of 59.9%, 7.7%, 0.4%, and 0.2%. This indicates that when the secondary pouring interval exceeds 28 days, the time interval has an extremely negligible effect on the mechanical properties of concrete with cold joints.<\/p>\r\n

Secondary pouring interval; concrete cold joint; splitting tensile strength; flexural strength<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-35\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2559-2570<\/span>\r\n <\/td>\r\n <\/tr>\r\n
36.<\/td>\r\n \r\n \r\n


Mapping a Decade of Coastal Edge and Coastal Zone Dynamics in Southeast Asia: A Systematic Review of Techniques and Methodologies<\/b><\/a><\/p>\r\n

Syazmin Sulaiman, Khairul Nizam Abdul Maulud*, Noorashikin Md Noor, Effi Helmy Ariffin & Anizawati Ahmad<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Coastal zones in Southeast Asia face escalating threats from climate change, necessitating robust monitoring techniques for effective management; however, a fragmented understanding of the methodologies used over the past decade persists. This study addresses this gap by conducting a systematic literature review, guided by the PRISMA (Preferred Reporting Items for Systematic review and Meta analysis), to comprehensively catalogue and analyse the techniques and methodologies for mapping coastal edge and zone dynamics in Southeast Asia from 2014 to 2024. The review was driven by the central research question: \u201cWhat are the most commonly used techniques and methodologies for mapping coastal edge in Southeast Asia over the past decade?\u201d Following a rigorous screening and quality appraisal process of 437 identified records, 48 high-quality articles were synthesized. The findings reveal four dominant themes: (1) the evolution and synergistic use of data sources, primarily Landsat and Sentinel constellations; (2) prevalent techniques for shoreline extraction and change analysis, notably the Digital Shoreline Analysis System (DSAS); (3) the adoption of advanced methodologies, including machine learning and integrated modeling; and (4) a synthesis of integrated workflows and a distinct geographical research bias. The study\u2019s significance lies in providing a consolidated methodological framework for researchers and a critical evidence base for policymakers, while its primary recommendation is the urgent need to address the identified geographical research gaps in under-studied Southeast Asian nations to foster equitable and informed coastal governance.<\/p>\r\n

Coastal dynamics; Southeast Asia; remote sensing; shoreline change analysis; climate change<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-36\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2571-2588<\/span>\r\n <\/td>\r\n <\/tr>\r\n
37.<\/td>\r\n \r\n \r\n


Fatigue Life Reduction Due to Weld Defects in Submarine Pressure Hull Materials: A Review<\/b><\/a><\/p>\r\n

Arif Pambudi*, Agoes Santoso & Ahmad Baidowi<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Weld defects represent a critical challenge in the structural reliability of submarine pressure hulls, where components operate under severe cyclic hydrostatic loading and corrosive deep sea environments. In high strength steels and titanium alloys commonly used for submarine fabrication, welding introduces microstructural heterogeneity, residual tensile stresses, and geometric discontinuities that significantly reduce fatigue life. Even small imperfections such as porosity, inclusions, lack of fusion, and weld toe cracks act as potent stress concentrators, accelerating crack initiation and early propagation. These effects are intensified in spherical and cylindrical pressure hulls, where complex three dimensional stress fields and nonstandard crack shapes limit the applicability of conventional fatigue models. Hydrostatic compression, combined with residual stress redistribution, further promotes unexpected crack growth behavior, reducing fatigue thresholds and shortening service life. Evidence from experimental studies and numerical simulations consistently reveals that defect morphology, HAZ softening, local stiffness reduction, and environmental factors jointly govern fatigue degradation in submarine welds. Moreover, early short crack growth contributes disproportionately to total fatigue damage, emphasizing the need for defect sensitive assessment methods. Furthermore, localized plastic deformation at defect tips under extreme hydrostatic pressure necessitates fracture mechanics models explicitly accounting for non idealized crack geometries. This review synthesizes current understanding of how welding induced imperfections influence submarine pressure hull fatigue performance and highlights major research gaps related to multi axial loading, crack shape evolution, and deep sea failure mechanisms. The findings support the development of improved welding practices, advanced inspection techniques, and refined fatigue life prediction frameworks tailored for submarine structural safety.<\/p>\r\n

Submarine pressure hull; weld defects; fatigue life; crack growth; residual stresses<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-37\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2589-2602<\/span>\r\n <\/td>\r\n <\/tr>\r\n
38.<\/td>\r\n \r\n \r\n


Influence of Polyurethane Modification on the Mechanical and Frictional Properties of Cold Mix Asphalt<\/b><\/a><\/p>\r\n

Ahmad Syafiq Iskandar Ahmad Nazri, Diana Che Lat*, Ab Aziz Mohd Yusof, Ismacahyadi Bagus Mohamed Jais, Atiqah Najwa Zainuddin, Doris Asmani Mat Yusof, Mohd Jamalludin Aman & Roslizayati Razali<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

Cold Mix Asphalt (CMA) is not only appealing in low-energy and low-emission pavement work but it tends to have poor mechanical and surface performance. The research question is the investigation of the possibility of using low-dose polyurethane (PU) modifier to improve CMA without jeopardizing skid safety. PU (6% by aggregate mass) was mixed into CM-100 emulsion and tested by laboratory tensile and direct shear tests in polyol: isocyanate ratios (1:1, 2:1), curing time (1, 3, 7, 15 days), and environmental conditioning (dry, wet). The British Pendulum Tester (ASTM E303) was used to measure field skid resistance on six patched potholes on dry and wet surfaces at early age (4 hours) and after curing (7 days). The findings demonstrate that the 1:1 ratio gave the best ultimate tensile stress at 15 days, which is a densely cross-linked yet brittle matrix, and 2:1 gave a consistently higher ductility and strain capacity. Shear behaviours have different pattern, where 2:1 variant delivered the most balanced stress-strain response, while 1:1 generally have reduced shear strength. Both PU-CMA and control CMA had a higher skid resistance than the Transport and road Research laboratory (TRRL) threshold values at all ages and anticipated decreases on wet surfaces, PU-CMA was similar to CMA in dry and wet conditions. In general, low-dose PU can be implemented in CMA to enhance mechanical strength and toughness without compromising the necessary skid resistance, which is sustainable and quick in pavement maintenance (median-to-heavy traffic) conditions.<\/p>\r\n

Cold Mix Asphalt (CMA); Polyurethane (PU) modification; tensile and shear strength; skid resistance; sustainable pavement materials<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-38\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

\r\n 2603-2615<\/span>\r\n <\/td>\r\n <\/tr>\r\n
39.<\/td>\r\n \r\n \r\n


Enhancing Antibacterial Properties Using Silver Doped Zinc Oxide Nanoparticles<\/b><\/a><\/p>\r\n

Nur Farihah Alya Adanan, Affa Rozana Abdul Rashid* & Mohd Riza Mohd Roslan<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

This study investigates the enhancement of material properties with a particular focus on the antibacterial performance of Ag-doped ZnO for potential biomedical applications. Undoped ZnO often exhibits limited antibacterial efficiency, therefore, this study investigates property enhancement through controlled Ag doping. Undoped and Ag-doped ZnO nanoparticles were synthesized via the precipitation method using silver (Ag) doping concentrations of 0.2%, 0.6%, and 1.0%. X-ray diffraction (XRD) revealed that the crystallite size decreased from 42.97 nm for undoped ZnO to to 43.18 nm, 36.39 nm, and 36.26 nm for 0.2%, 0.6%, and 1.0% Ag-doped ZnO, respectively, indicating inhibited crystal growth with increasing Ag content. Fourier-transform infrared spectroscopy (FTIR) confirmed the Zn\u2013O and Ag\u2013O stretching vibrations at 500\u2013600 cm-\u00b9, verifying the successful synthesis. Field emission scanning electron microscopy (FESEM) showed agglomerated plate-like structures in undoped ZnO, while Ag-doped samples exhibited smaller, compact, and densely clustered morphologies, demonstrating the influence of Ag incorporation on surface features. Energydispersive X-ray (EDX) analysis confirmed Zn and O as main constituents, with Ag signals detected up to 1.51 weight % in the 1%Ag-doped sample, validating successful doping. Antibacterial activity, tested using the disc diffusion method against Escherichia coli, showed an average inhibition zone of 15.67 mm for undoped ZnO, increasing to 19.33 mm at 0.2%Ag-doped ZnO, highlighting enhanced antibacterial performance. These findings provide valuable insights into the potential of Ag-doped ZnO as an advanced material for biomedical and health-related applications.<\/p>\r\n

Antibacterial coatings; Ag-doped ZnO; Precipitation method; disc diffusion method; Escherichia coli (E. coli)<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-39\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

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40.<\/td>\r\n \r\n \r\n


Tackling Imbalanced Data for Improved Machine Learning-Based Routing in Delay-Tolerant Networks<\/b><\/a><\/p>\r\n

Usama Shaker Hachim, Asma Abu-Samah\u2217, El Arbi Abdellaoui Alaoui, Nor Fadzilah Abdullah, Amine Salah, Anand Nayyar & Ziad Qais AlAbbasi<\/p>\r\n

<\/span>Abstract<\/span>

<\/p>\r\n

A Delay Tolerant Network (DTN) is designed for intermittent connectivity and long delays environments, using a store-and-forward approach to transmit data. Machine Learning in Delay Tolerant Networks (DTNs): Prediction of link availability, routing optimization and adaptation to network dynamics. Machine learning models improve the efficiency of data transfer, thus reducing latency and enhancing decision making. This improves the robustness of the communication in the applications of remote sensing and disaster recovery. In addition, machine learning has shown promising application to design intelligent routing strategies for DTNs, which can improve communication efficiency in highly dynamic environments. The data unbalance due to different message generation rates and network connectivity has a negative impact on the performance of ML-based DTN routing algorithms. This results in biased predictions and sub-optimal routing decisions. The issue of imbalanced data in machine learning based DTN routing is examined in this study using four common protocols: Epidemic, Spray and Wait, Prophet, and MaxProp. We compare different oversampling strategies with six classifiers: Random Forest, Extra Trees, XGBoost, Bagging Classifier, Decision Tree and K-Nearest Neighbors. We discuss different data pre-processing techniques, algorithmic approaches and pertinent evaluation measures. Our analysis finds the best approaches for handling data imbalance problems. Among the methods considered, SMOTENN with Extra Trees classifier consistently obtained the highest accuracy in all four procedures. The application of these tactics resulted in an impressive improvement in model performance - accuracy increased by 13.58% (from 81% to 92%) and thus improving the robustness and fairness of ML-based DTN routing protocols.<\/p>\r\n

Delay-Tolerant Networking, Machine Learning, Imbalanced Data, Routing Protocols Performance Evaluation Metrics, Data Pre-processing Techniques, Robustness<\/p>\r\n

<\/div><\/span>\r\n DOI : https:\/\/dx.doi.org\/10.17576\/jkukm-2026-38(5)-40\r\n <\/a>\r\n <\/span><\/sub><\/p>\r\n <\/td>\r\n

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Volume 38 (05) August 2026 Table of Content No. Article Page 1. Carbon Footprint of Food Waste for Campus Sustainability: Insights from UniKL MICET Mohd …<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"elementor_header_footer","meta":{"footnotes":""},"folder":[],"class_list":["post-6093","page","type-page","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t