Now showing 1 - 10 of 28
  • Publication
    Surface characterization of laser-induced molten area in micro-grooving of silicon by ultraviolet (UV) laser
    ( 2021-10-25)
    Raman N.S.A.
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    Nordin I.H.W.
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    ; ;
    Abdullah S.S.C.
    The objective of this research is to understand the fundamental mechanisms that govern the formation of laser-induced molten area during the micro-grooved fabrication on silicon material. In this research work, micro grooves were fabricated on silicon wafer by using ultraviolet (UV) laser of 248nm wavelength. Influence of lasing parameters such as pulse duration, laser pulse energy and scanning speed on the surface of micro-grooved was characterized. It is found that, the width of the micro grooves become wider with increasing laser pulse energy when ultraviolet laser was irradiated on silicon material. On the other hand, heat affected zone (HAZ) can be found at the surface of micro groove line at high pulse energy, high pulse repetition rate and lower scanning speed irradiation condition. This is considered due to the excessive heat input of the laser irradiation condition. It is concluded that proper selection of laser processing parameters of pulse energy, E, pulse repetition rate, Rp, and scanning speed is necessary to achieve high quality micro-grooves.
  • Publication
    A study on the significance of exhaust manifold’s bending angle to the brake torque of 115cc SI engine
    ( 2023-01-01)
    Murali R.
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    ; ; ;
    Azizul A.I.
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    Rani M.F.H.
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    Sunan S.
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    Ali M.H.A.
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    Ramasamy G.
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    Hisham M.H.N.
    The exhaust manifold is a crucial component of the exhaust system in any SI engine, responsible for efficiently expelling combustion products. However, when the exhaust manifold's design is suboptimal, it leads to negative consequences for the engine's performance due to the presence of backpressure. Backpressure refers to the difference between maximum exhaust pressure and atmospheric pressure. An increase in backpressure decreases the overall performance and fuel efficiency of an SI engine. This study aimed to investigate the bending angle characteristics of the exhaust manifold and the brake torque of the 115cc SI engine using 1D engine analysis. The relationship between the exhaust manifold's bending angle characteristics and the brake torque was analysed using Analysis of Variance (ANOVA) with a p-value of less than 0.05, while the validation with experimental data showed a maximum error of 6.62. In the previous research, it was noted that a lower bending angle leads to better performance. However, the current results indicate that out of the three bending angles considered, having one of them yields the most substantial enhancement in brake torque. The optimized bending angle configuration obtained from the analysis increased the mean brake torque by 0.011 Nm (0.14%). Consequently, this study enhances the average brake torque through the optimal bending angle characteristics of the exhaust manifold. The study's objective aligns with Sustainable Development Goal (SDG) 9: Industry, Innovation, and Infrastructure, as the improved performance achieved through an optimal exhaust manifold design configuration is expected to promote domestic technology development.
      1  20
  • Publication
    Comparative study of surface temperature of lithium-ion polymer cells at different discharging rates by infrared thermography and thermocouple
    ( 2020-06-01)
    Rani M.F.H.
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    ; ;
    Ibrahim Z.
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    Wan W.K.
    The objective of this study was to compare the surface temperature of lithium-ion polymer cells at different discharging rates by infrared thermography and thermocouple measurement. The cells were discharged by using a battery workstation at discharging rates of 2.0 A, 4.0 A, 6.0 A, 8.0 A, and 10.0 A in a controlled testing condition. This study focused on surface temperature distribution, maximum surface temperature, and temperature rise evolution. Higher discharging rate generates more heat in LiPo cells, which causes larger temperature gradient, higher maximum surface temperature, and higher temperature rise. During the discharging process, non-uniformity spatial distribution of LiPo cells was observed. No critical surface temperature was observed when reaching towards the end of discharging process as the surface temperature distribution managed to become spatially uniform. Most of the maximum surface temperatures were spotted at the lower part of the LiPo cells. In addition, the captured infrared (IR) images found that the temperature rises rapidly at higher discharging rates. In comparison, surface temperature measurement by infrared thermography provided higher accuracy than thermocouple. The findings of this study provide evidences in better development of battery thermal management systems with consideration of surface temperature distribution and temperature rise.
      2
  • Publication
    Development of Driving Simulation Experiment Protocol for the Study of Drivers’ Emotions by using EEG Signal
    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.
      1  32
  • Publication
    An Experimental Framework for Assessing Emotions of Stroke Patients using Electroencephalogram (EEG)
    This research aims to assess the emotional experiences of stroke patients using Electroencephalogram (EEG) signals. Since emotion and health are interrelated, thus it is important to analyse the emotional states of stroke patients for neurofeedback treatment. Moreover, the conventional methods for emotional assessment in stroke patients are based on observational approaches where the results can be fraud easily. The observational-based approaches are conducted by filling up the international standard questionnaires or face to face interview for symptom recognition from psychological reactions of patients and do not involve experimental study. This paper introduces an experimental framework for assessing emotions of the stroke patient. The experimental protocol is designed to induce six emotional states of the stroke patient in the form of video-audio clips. In the experiments, EEG data are collected from 3 groups of subjects, namely the stroke patients with left brain damage (LBD), the stroke patients with right brain damage (RBD), and the normal control (NC). The EEG signals exhibit nonlinear properties, hence the non-linear methods such as the Higher Order Spectra (HOS) could give more information on EEG in the signal's analysis. Furthermore, the EEG classification works with a large amount of complex data, a simple mathematical concept is almost impossible to classify the EEG signal. From the investigation, the proposed experimental framework able to induce the emotions of stroke patient and could be acquired through EEG.
      1  17
  • Publication
    Derivation and validation of heat transfer model for Spark-Ignition engine cylinder head
    The valve train is located in the engine cylinder head, which has various operational heat transfer mechanisms to accommodate the combustion process. Most heat transfer studies in this area have only addressed medium-to high-power vehicles at a single running speed. In this study, a model of an air-cooled underbone motorcycle valve, valve seat, and engine cylinder head was tested to determine the thermal characteristics using actual engine operating conditions at low, medium, and high engine speeds. One-dimensional thermal simulation analyses were conducted to obtain the instantaneous heat-transfer coefficients of an actual engine. The average thermal value was determined as the boundary condition in the three-dimensional thermal analysis. A three-dimensional model was prepared using the ANSYS commercial computational fluid dynamics software package. The results show that as the engine speed increases, so does the thermal load toward the component in the engine cylinder head. The strongest temperature regions were concentrated around the combustion face. The exhaust valve held most of the heat, with the valve neck recording the highest temperature. For the intake valve, the combustion face registered the majority of the heat. The heat flux intensity was gathered in the contact surface area between the valve and its seat, between the valve stem and guide, and between the stem guide and tip section. A thermal survey was used to validate the three modelling results for two separate engine datasets. The cumulative relative errors for intake and exhaust valve seats for low engine speeds were 3.73% and 0.17%, respectively. The intake and exhaust valve seats had cumulative relative errors of 4.12% and 0.70%, respectively, at intermediate speeds. This methodology provides valuable information for analysing the heat characterisation of air-cooled engines. It can also be a useful blueprint for the automotive industry and other researchers involved in thermal measurements.
      32  2
  • Publication
    Design of Experiment (DOE) for the Investigation of Human Emotions while Driving in a Virtual Environment through Brain Signal (EEG)
    The transition from the conventional vehicle to the autonomous vehicle is going to take place but, the acceptance of users to the autonomous vehicle still lacking. The past research more focusses on the driver attention, drowsiness, fatigue or the alertness of the driver. This research aims to study the drivers' emotions/reactions during the autonomous and manual drive in the simulated environment. The environment for the manual and autonomous drive is developed by using simulator software, Unity. This paper focus only on the experimental setup for the human emotions' detection using EEG signal during the manual and autonomous drive. The Emotiv Epoc+ use for the EEG signal acquisition. The simulated environments are displayed through a Head Mount Display (HMD). The analysis of the EEG signal which includes the pre-processing, feature extraction, and classification will be discussed in future works.
      1  25
  • Publication
    Drill Bit Design and Its Effect on Temperature Distribution and Osteonecrosis During Implant Site Preparation: An Experimental Approach
    In this study, the drilling parameters will be evaluated to obtain optimal parameters in minimizing the impact of drilling damage on synthetic bone blocks. The effect of damage observed in the study is osteonecrosis that occurs in the drill hole for implant site preparation, where a smaller value is desired. The drilling parameters are optimized using the Taguchi method with two control factors: the feed rate and spindle speed; each parameter is designed in five levels. This experiment was then carried out on four different designs of drill bits, i.e., Twist (118°and 135°), spherical, and conical drill bits. While experimental planning uses L25 orthogonal arrays, the "smaller is better" approach is used as a standard analysis. The main findings of this research are 118° point angle twist drill bit is the ideal type of drill bit for bone drilling, as it produces less heat than other types of drill bits. The optimal range of feed rate and drilling speed for bone drilling is 40-60 mm/rev and 1000-1400 RPM, respectively. Combining these parameters helps to minimize heat generation during implant site preparation drilling.
      1  34
  • Publication
    Energy absorption behavior of oil palm empty fruit bunch fiber-reinforced composites subjected to low-velocity impact
    ( 2024-05-01)
    Abdul Rahman M.K.F.
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    Abu Bakar S.
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    Md Tamrin S.B.
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    Israr Ahmad H.A.
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    Ng Y.G.
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    In this study, oil palm empty fruit bunch (OPEFB)-reinforced composites were subjected to a low-velocity impact test to study their energy absorption characteristics. Two sets of OPEFB-reinforced composite specimens were used, comprising 30:70 and 40:60 fiber/epoxy fractions. One set of specimens was treated with a 3% NaOH solution. The drop impact responses, fragmentation characteristics, energy absorptions, and residual strengths of both sets of specimens were analyzed. Drop impact tests were performed using three different energy levels, namely, 10, 13, and 16 J. In general, the results indicated that all the untreated specimens absorbed higher energy than that of the treated specimens, thus suffering severe surface and structural damage. This result is attributed to the treated specimens providing a better interlocking mechanism between the matrix and fibers and dissipating the impact energy through the impactor. Regarding fiber loading, all the 30:70 fiber/epoxy composites exhibited slightly less energy absorption than the 40:60 fiber/epoxy composites.
      2
  • Publication
    Thermal Management System Analysis Concentrate on Air Forced Cooling for Small Space Compartment and Heat Load
    ( 2021-12-01)
    Yahaya M.N.
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    Ghani A.Z.A.
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    Rahman A.A.
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    Bakar S.A.
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    Harun A.
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    Hashim M.S.M.
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    ; ;
    Kamarrudin N.S.
    Battery thermal management system (BTMS) plays an important thing as to control of the battery thermal behaviours. Recently, most of the manufacturer either in automobile, motorcycle, and electric vehicle (EV) industry are using this application of BTMS for their product. It is because BTMS promising the extend the period and lifespan of the battery and the battery system controlling the temperature distribution and circulation on the system. Lithium-ion battery is one of the common usages in BTMS. Lithium-ion battery promising the goals such as higher performance, better cycle stability, and improved protection are being followed with the selection and engineering of acceptable electrode materials. It also shows a goal for future such as high of the energy storage due to higher energy density by weight among other rechargeable batteries. However, there still have factor that are limiting the performance/application when using lithium-ion as battery thermal management system (BTMS). For example, the performance, cost, life, and protection of the battery. The main reason is therefore important in order to achieve optimum efficiency whenworking under different conditions. Hence, the best range of temperature and the cooling capacity of lithium-ion battery need to evaluate in order to increasing the lifespan of lithium-ion battery at the same time can increasing the performance of the cell. This study found that the higher the velocity of air, the higher the cooling capacity that gain from the surrounding. It also was strongly related to the dry bulb temperature of surrounding air.
      29  1