Shahriman Abu Bakar

The internal combustion engine (ICE) remains pivotal in motorcycle technology, primarily due to its efficiency, energy density, and established infrastructure, despite the rise of electric vehicles. This study examines the influence of intake manifold design parameters on the performance of a single-cylinder internal combustion engine (ICE), with a specific focus on brake power and brake torque at high engine speeds. A comprehensive parametric analysis was conducted using a 1D simulation model in Ricardo Wave, evaluating the effects of manifold length, diameter, and bending angle on engine performance metrics. The results demonstrate that the optimized intake manifold design yields a 7.75% improvement in brake power and a 6.5% enhancement in brake torque at 10,000 RPM compared to the baseline configuration. Mid-range values for manifold length and diameter were found to achieve optimal airflow dynamics, effectively minimizing pressure losses. Additionally, a bending angle of 70° exhibited superior stability in power delivery at elevated engine speeds. These findings underscore the critical role of intake manifold geometry optimization in achieving enhanced engine performance under high-speed operating conditions.

This study investigates the vertical distribution of temperature and relative humidity within dental treatment rooms at a Government Type 3 Health Clinic in Gial Perlis, Malaysia, addressing a significant gap in the literature regarding environmental conditions in dental healthcare settings. Precise measurements were conducted at four specific heights 0.3 m, 1.0 m, 1.7 m, and 2.7 m utilizing calibrated digital thermometers with hygrometers to capture accurate environmental data. The collected data were analysed using Analysis of Variance (ANOVA) to assess the significance of variations across these levels. Results revealed statistically significant differences in both temperature and relative humidity (p < 0.05). At the uppermost level (2.7 m), the highest mean temperature of 22.1°C and a mean relative humidity of 68.2% were recorded, while the lowest level (0.3 m) exhibited the lowest mean temperature of 20.9°C and the highest mean relative humidity of 73.8%. Temperatures at the patient level (1.0 m and 1.7 m) averaged between 21.0 °C and 21.6°C, which is slightly below the optimal comfort range of 22°C to 26°C. These vertical gradients indicate that the existing HVAC systems may not be effectively regulating indoor conditions, potentially impacting patient comfort, the performance of temperature-sensitive dental materials, and the effectiveness of infection control measures due to altered aerosol behaviour. The findings underscore the necessity of optimizing HVAC designs to achieve uniform temperature and humidity distributions within dental treatment rooms. This research provides valuable insights for healthcare professionals and policymakers, emphasizing the importance of tailored environmental management strategies to enhance patient comfort, procedural outcomes, and safety in dental healthcare settings.

The potential of nanofluids in improving heat transfer efficiency is well recognized, although there is a lack of clarity regarding the methods for assessing their stability and the influence on thermophysical properties. Moreover, the prevention of nanoparticle aggregation, which is essential for stability, requires further investigation. This study aims to address these issues by investigating the thermodynamic properties and stability of Al2O3/deionized water and CuO/deionized water nanofluids, which were prepared using magnetic stirring and ultrasonication. The stability assessment, conducted through standard deviation analysis, revealed that CuO (80 nm)/deionized water nanofluids exhibited greater stability compared to Al2O3 (80 nm)/deionized water nanofluids. The research explored the impact of temperature, volume concentration, and nanoparticle type under both static and dynamic conditions. Static tests focused on measuring thermal conductivity, viscosity, and specific heat, while dynamic tests involved a heat exchanger setup to determine heat transfer rates. The findings indicated that CuO nanofluids displayed the highest thermal conductivity and the most significant reduction in specific heat and heat transfer rate. Viscosity was found to increase with nanoparticle concentration and decrease with temperature. This study provides valuable insights into the thermophysical characteristics and stability of nanofluids, emphasizing the advantages of CuO-based nanofluids for heat transfer applications.

In recent years, there are many applications where synthetic fibers and natural fibers are used as reinforcing materials in composites, such as the automotive and aerospace industries, the medical industry, and the construction industry. While these hybrid fibers effectively enhance mechanical and electrical properties, research into electrical characteristics remains inadequate and is an ongoing endeavor. In this work, synthetic woven glass fibers and natural woven kenaf fibers were used to fabricate composite materials by vacuum infusion technique. The dielectric properties of three different substrates, glass fibers, kenaf fibers and glass/kenaf fibers reinforced epoxy composites were investigated at 0° orientation. The ENA Network Analyzer was used to measure dielectric properties in a wide microwave frequency range. The substrates were single-joint overlapped with an adhesive and then mechanically tested. The shear strength of the joint as a function of strain, was tested using a Shimadzu universal testing machine. Visual inspections were performed to determine the failure modes of the composites. The dielectric constant and loss factor of the glass fiber composite were the highest, while the kenaf fiber composite had the lowest value. When a small amount of glass fibers is incorporated into kenaf fibers, which is called a hybrid composite, the polarization increases and the mechanical strength also increases compared to the kenaf fiber composite. Scanning electron microscopy (SEM) of the fractured tensile tests was performed to understand the nature of the interfaces between glass, kenaf and matrix. The kenaf/matrix interface was heterogeneous but exhibited voids, resulting in low dielectric properties and mechanical strength. By inserting a small amount of glass fibers, the hybrid with kenaf fibers improve the dielectric constant by 20.7% and the dielectric loss factor by 27% compared with the kenaf fiber composite. The results also show that the composites exhibit a correlation between the dielectric properties, tensile strength, and the morphological nature of the interfaces.

The Brain-Computer Interface (BCI) is a field of research that studies the EEG signal in order to elevate our understanding of the human brain. The applications of BCI are not limited to the study of the brain wave but also include its applications. The studies of human emotions specific to the vehicle driver are limited and not vastly explored. The EEG signal is used in this study to classify the emotions of drivers. This research aims to study the emotion classifications (surprise, relax/neutral, focus, fear, and nervousness) while driving the simulated vehicle by analyse the EEG signals. The experiments were conducted in 2 conditions, autonomous and manual drive in the simulated environment. In autonomous driving, vehicle control is disabled. While in manual drive, the subjects are able to control the steering angle, acceleration, and brake pedal. During the experiments, the EEG data of the subjects is recorded and then analyzed.

Working fluids play a crucial role in closed systems to ensure efficient performance, particularly in systems for heating, cooling, or power generation, where the heat transfer coefficient is pivotal. This study delves into the thermodynamic properties and stability of copper oxide (CuO) nanofluids as alternative working fluids in closed systems. Investigating colloidal suspensions of CuO nanoparticles, the research aims to enhance heat transfer efficiency. CuO nanoparticles, sized at 40nm and 80nm, were dispersed in base fluids like water, ethylene glycol, and oil sans surfactants. The study, divided into static and dynamic phases, examines key nanofluid properties including viscosity, thermal conductivity, specific heat, and heat transfer rate. Through methodologies such as KD2 Pro for thermal conductivity, rheometer for viscosity, and small heat exchanger for heat transfer rate analysis, the effects of volume concentration, temperature, and nanoparticle size on nanofluid performance were evaluated. Sedimentation analysis employed both quantitative (standard deviation calculations) and qualitative (sediment capture methods) approaches. The findings highlight the superior heat transfer rate of 40nm CuO nanofluid at 0.467% volume concentration which is 9.08 kJ/s, suggesting its potential to optimize system efficiency, particularly in heating, cooling, and power generation applications.

This study aimed to elucidate the influences of several drilling parameters on bone temperature during drilling, as excessive heat generation can cause thermal bone damage and affect post-surgery recovery. In vitro drilling tests were conducted on bovine femoral shaft cortical bone specimens. The parameters considered included tool rotational speed (s), feed rate (f), tool diameter (d), and drill tip angles of 118° and 135°. Drilling temperatures were studied across a range of 800–2000 rpm rotational speeds, 20–40 mm/min feed rates, and 2–4 mm drill diameters. A predictive statistical model was constructed using the response surface methodology (RSM). Analysis of variance (ANOVA) at a 95% confidence level (α = 0.05) revealed that rotational speed significantly impacted temperature increase, contributing to 59.74% of observed temperature rises. Drill diameter accounted for 16.21% of temperature variations, while feed rate contributed to 10.04% of the temperature rises. The study provides valuable insights into the predominant factors affecting bone temperature during drilling. Understanding these parameters and their interplay is pivotal for optimizing drilling conditions and minimizing potential thermal damage to bones.