Journals of Universiti Tun Hussein Onn Malaysia (UTHM)
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Computational Intelligence and Load To Source Ratio Index Based Technique for Voltage Security Restoration
Get PDFVoltage security remains a critical concern in power systems, as voltage instability can lead to service disruptions and cascading failures. This paper presents an advanced computational intelligence technique based on the load-to-source ratio index, integrated with Evolutionary Programming (EP) to enhance voltage stability. Unlike conventional methods, this approach optimizes reactive power dispatch (ORPD) across multiple configurations to improve voltage levels throughout the network. The technique was validated on the IEEE-30 Bus Reliability Test System under various loading conditions. Results show significant improvements in the index for weak buses, with an increase from 10.9667 to 24.3144 at the critical Bus 29, leading to improved voltage levels across the system. Additionally, the method offers enhanced flexibility by assessing multiple ORPD scenarios, allowing system operators to choose the optimal configuration for different network conditions. These findings suggest that the proposed method not only improves voltage security but also provides a robust, adaptable solution for practical power system operations
Impact of Autonomous Vehicles on Control Delay & Safety: A Case Study of Signalized Tight Diamond Interchange at Executive Towers Business Bay, Dubai
Get PDFAutonomous Vehicles (AVs) promise to transform urban mobility by improving traffic flow and safety, but their actual impact under varied traffic and geometric conditions remains uncertain, warranting further study. This study evaluates the impacts of AVs on the operational and safety performance of a signalized tight diamond interchange at Executive Towers Business Bay, Dubai, under mixed traffic conditions. Three AV driving logics: aggressive, normal and cautious, were gradually introduced, replacing conventional cars while maintaining a constant mix of 2% heavy vehicles and 1% buses. A calibrated and validated traffic model was developed in PTV VISSIM using site-specific geometric and operational data, with maximum queue length used as the measure of effectiveness (MOE). Thirteen scenarios were simulated to evaluate varying AV penetration levels. Delay outputs were extracted from VISSIM, while vehicle trajectory files were analyzed in the Surrogate Safety Assessment Model (SSAM) using TTC thresholds of 1.5 and 1.0 seconds. Calibration yielded optimal values for VISSIM’s car-following parameters: average standstill distance (1.35 m), additive part of safety (0.75 m), and multiplicative part of safety (1.50 m). Results showed that at a demand level exceeding 5,000 veh/hr, AV-Aggressive at 100% penetration reduced average delay by 7.5% and total conflicts by 48.6% compared to conventional vehicles. In contrast, AV-Cautious increased delay by 90.6% and conflicts by 69.2%. AV-Normal caused a modest 3.5% increase in delay but reduced conflicts by 26.7%. Overall, Scenario 13, 100% AV-Aggressive—demonstrated the best operational and safety performance. These results highlight the critical role of AV driving logic in shaping interchange performance, with aggressive AV behavior at full penetration offering the most substantial improvements in delay reduction and conflict mitigation. This suggests that future AV integration strategies should consider behavior modeling as a key factor in optimizing traffic operations and safety in complex urban environments
Rutting Performance Evaluation Using Waste Cooking Oil and Ground Tire Rubber in Asphalt Mixture
Get PDFThe quality of road pavement is a critical factor in establishing an efficient transportation system. To address issues like fatigue cracking and rutting, significant efforts have been devoted to enhancing pavement quality and adopting innovative design approaches. Recent years have seen a growing interest among traffic engineers in improving asphalt performance by incorporating various additives and substituting traditional asphalt binder materials with recyclable alternatives. This study involves blending bitumen grade 80/100 with varying percentages (0%, 1%, 2%, 3%, and 4%) of waste cooking oil (WCO) and 20% ground tyre rubber (GTR), relative to the weight of the bitumen. The physical and rheological properties of both the base bitumen and the modified binder were assessed through penetration, softening point, and dynamic shear rheometer (DSR) tests. As a result of this modification, the specifications of the modified binder are expected to align with those of bitumen grade 40/50, rendering bitumen 80/100 obsolete due to its subpar performance. The research findings indicate that the optimal content for the modified binder is 1% WCO and 20% GTR. Furthermore, the Resilient Modulus (RM) test demonstrates that asphalt mixtures featuring GTR/WCO-modified binders exhibit a reduced susceptibility to rutting compared to conventional bitumen-based asphalt mixtures. This suggests the potential for more durable and rut-resistant road surfaces, aligning with the broader goal of improving transportation infrastructure
Turbidity Trends in 20 Water Treatment Plants Across Sabah, Malaysia: Implications for Sustainable Water Resource Management
Get PDFWater Treatment Plants (WTPs) play a vital role in ensuring safe drinking water by removing contaminants, with turbidity serving as a key indicator of raw water quality. However, turbidity levels in raw water sources are increasingly influenced by extreme weather events and anthropogenic activities, presenting challenges for effective water treatment. This study aims to assess turbidity trends and identify contributing factors in WTPs across Sabah, Malaysia, to support more sustainable water management practices. Turbidity data from the WTPs, spanning 1 to 8 years, were analysed, supplemented by time-lapse satellite imagery to assess upstream catchment conditions wherever possible. Data were categorised into four administrative divisions - West Coast, Kudat, Interior, and Tawau divisions - and examined for temporal and spatial variations. The analysis revealed frequent turbidity spikes, particularly in the Tawau and Interior divisions, with some WTPs, such as Kalabakan and Beaufort I & II, recording levels exceeding 1000 Nephelometric Turbidity Units (NTU), which is the operational shutdown threshold used by WTPs to prevent treatment failure and equipment damage. Kalabakan recorded a peak turbidity of 2,264 NTU, while Beaufort I and II reached 2,528 NTU, more than twice the downtime threshold. These elevated levels were closely linked to extensive land clearing and agricultural activities. The study underscores the importance of integrated water resource management, including erosion control, reforestation, and stricter land-use regulations. To improve operational resilience, real-time turbidity monitoring and predictive modelling are recommended to enhance WTP resilience and ensure a sustainable water supply in tropical regions amidst intensifying environmental pressures
Green Roofs as a Sustainable Building Practice: A Lab-Scale Evaluation Using Recycled Waste Materials for Stormwater Runoff Control
Get PDFSustainable building in Malaysia is gaining momentum as developers increasingly adopt eco-friendly practices to mitigate environmental impact and promote long-term sustainability in response to rapid urbanization and climate challenges. Green roofs play a crucial role in the sustainable building movement by enhancing insulation, managing stormwater, and supporting biodiversity. Despite these benefits, green roofs remain rarely adopted in Malaysia. Thus, the objective of this study is to evaluate the performance of green roofs for stormwater control by testing two laboratory-scale models utilizing: (i) commercial materials and (ii) recycled waste materials. The findings revealed that green roofs significantly reduced stormwater runoff compared to conventional roofs, with green roofs with recycled materials achieved up to 72% peak flow reduction, exceeding the performance of those with commercial materials, which achieved up to 54% reduction. Thus, green roofs can contribute to sustainable development by managing stormwater effectively, and the incorporation of recycled materials enhances the performance of a green roof but also lowers construction costs, making sustainable practices more economically viable for developers and builders
Sustainable Water Quality Improvement in Small-Scale Tilapia Ponds Through Bio-DHS Filtration
Get PDFThis study investigates the performance of Bio-Downflow Hanging Sponge (Bio-DHS) filtration in improving water quality for small-scale Tilapia aquaculture, addressing sustainability and resource efficiency challenges. The Bio-DHS system introduces a zero-exchange water management approach, eliminating the need for water replacement by only adding small amounts to compensate for evaporation and sampling losses. This method aligns with SDG 12 (Responsible Consumption and Production) by promoting efficient water use and minimizing waste discharge. Results revealed progressive improvements in water quality, including reductions in Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), and Chemical Oxygen Demand (COD). Dissolved Oxygen (DO) levels increased to 7.00 mg/L during full-capacity operation, while nitrification efficiency reached 41.66%, indicating effective nitrogen cycling. The Water Quality Index (WQI) improved from 54.31 (polluted, Class III) without filtration to 68.20 (slightly polluted, Class III) with Bio-DHS filtration. While Class III water is suitable for aquaculture, fishery and livestock drinking, further optimization—such as extending Bio-DHS contact duration—could enhance quality for broader applications. By reducing pollutant loads in aquaculture, this system also supports SDG 14 (Life Below Water) by mitigating environmental impact and promoting cleaner water bodies. The Bio-DHS system is scalable and adaptable, making small-scale Tilapia fish ponds a viable, cost-effective solution for sustainable aquaculture in Malaysia. Future research should focus on optimizing microbial development and operational parameters to achieve higher WQI classifications
Post-Thermal Performance of Concrete Containing 60% of Slag
Get PDFPost-thermal performances of concrete have been studied extensively, as it is crucial to determine whether the structure can be used after a fire event; however, concrete properties can always be improved. One of the innovations introduced in concrete mixtures is the replacement of cement with industrial waste materials, such as slag. Concrete containing slag is already established in the construction industry. However, there is limited information regarding the post-thermal performance of concrete containing slag up to a 60% replacement. Hence, this study aims to investigate the post-thermal performance of concrete containing 60% slag replacement at ambient temperature and after exposure to elevated temperatures of 200°C and 500°C for one hour. Therefore, the properties of hardened concrete were determined. Three batches of 100 mm ´ 100 mm ´ 100 mm cubes specimens containing 0% (normal concrete, NC) and 60% slag replacement (concrete containing slag, CCS) were tested under compressive strength test. It was found that the compressive strength of CCS is 34.4 MPa, which is lower than that of NC, which achieved 40.6 MPa with 0.85 difference ratio. The residual compressive strength of CCS is 32.6 MPa, while NC has 47.4 MPa, with 0.69 difference ratio. The residual compressive strength decreases gradually with an increasing temperature exposure up to 500°C. A similar trend also occurs on modulus of elasticity (MOE); CCS has a decrease of elastic modulus compared to NC. In contrast for 200°C temperature exposure, CCS shows an increment about 19 on MOE value. However, both NC and CCS maintain a residual compressive strength exceeding 30 MPa, which remains within the acceptable target range. It can be concluded that slag can give an acceptable potential for the future in construction industry.
Finite Element Assessment of Short Stem in Hip Arthroplasty Based on Different Activities
Get PDFStress shielding is a phenomenon that occurs when an implant absorbs too much of the load that would typically be distributed to the surrounding bone, resulting in reduced mechanical stimulation of the bone. In hip arthroplasty, the implant\u27s design plays a crucial part in stress distribution at the interface of the implant and the adjacent bone. This study examines the stress distribution in hip arthroplasty implants using Finite Element Analysis (FEM), comparing conventional stems with short stems. Titanium alloy has been chosen as the material of the implant. Stress analysis has been conducted under five different activities: normal walking, walking upstairs, walking downstairs, standing, and sitting to study the effect of these activities on various lengths of stem. The results show that in the conventional stem, the highest stress concentrations occur at the joint and the tip of the implant, leading to stress shielding in the proximal area of the femur bone, which may result in bone resorption and potential implant complications over time. On the contrary, the short stem exhibits higher stress values at the neck of the implant for all activities. However, the short stem demonstrates a uniform stress distribution pattern compared to the conventional stem. In addition, the analysis found that conventional stem practices had higher stress levels throughout all activities than the short stem practices. Among the activities examined, walking activities generated the highest stress, followed by activities such as upstairs walking, normal walking, standing, and sitting. These findings provide insight into the mechanical performance of hip implants and suggest that short stems offer advantages in reducing stress shielding and enhancing longevity
Design Enhancement of Hose Rolling Tool for Firefighters Using DFMA
Get PDFFirefighting operations depend significantly on effective equipment, with hose rolling tools being crucial for the swift deployment and recovery of fire hoses. Existing hose roller designs frequently exhibit significant component counts, intricate assembly, and elevated manufacturing costs, which hinder operational efficiency and escalate manufacture expenses. This project seeks to improve the design of a hose rolling tool for firefighters by utilizing Design for Manufacturing and Assembly (DFMA) principles to decrease part complexity and cost. The project entailed evaluating the current hose roller design, highlighting inefficiencies, and methodically improving the tool through SolidWorks modelling and manual Design for Assembly (DFA) analysis. Comparative evaluations were performed to analyze part quantity, material expenses, and assembly durations between the original and revised models. The findings indicated a substantial decrease in total components (from 40 to 25), an 11% reduction in production expenses, and a 48% enhancement in assembly efficiency. These findings underscore the efficacy of DFMA in enhancing product design for manufacturing and assembly, resulting in more economical and user-centric firefighting equipment. In summary, the implementation of DFMA principles significantly enhanced the manufacturability and operational efficacy of the hose rolling tool, offering a viable framework for future advancements in firefighting equipment