Lim Eng Aik
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Preferred name
Lim Eng Aik
Official Name
Lim, Eng Aik
Alternative Name
Aik, Limeng
Lim, E. A.
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Scopus Author ID
23491376300
Researcher ID
EKL-8415-2022

Research Output

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  • Publication
    In-situ Noise Measurement and Analysis for the Motorcycle Muffler
    ( 2020-01-01)
    Tan Wei Hong
    ;
    Chuah H.G.
    ;
    Cheng Ee Meng
    ;
    Lim Eng Aik
    ;
    Lok, Chip Hao
    Noise from the vehicles is one of the noise pollutions to the environment. The noises emitted by the vehicles have to obey the requirement of regulation of maximum sound pressure level permitted for respective vehicles. In this study, the aim is to reduce the noise emitted from the motorcycle muffler. The noise emitted from the motorcycle muffler is analyzed and measured using a sound level meter. The average sound pressure level of the motorcycle muffler is determined in certain conditions. The sound pressure levels for original installed muffler are recorded as 76.4dB, 79.5dB and 82.3dB under the constant speed of 10km/hr, 20km/hr and 30km/hr respectively by engaging 2nd gear. For the acceleration with the scope of 0 km/hr to 30 km/hr, the difference of sound pressure level between 2nd and 4th gear engaged is 5.4dB. The study is continued by using a modified muffler which contains sound absorptive materials. The absorptive materials chosen are glass wool, cotton and Styrofoam and they are taking turn to be placed into the modified muffler to reduce the sound pressure level. Then the experiment is repeated. By applying 100g absorptive materials in the modified muffler, the reduction of sound pressure level are recorded as 12.6% (glass wool), 7.5% (cotton) and 4.4% (Styrofoam) compared with original installed muffler while 2nd gear engaged. Styrofoam is observed does not perform significantly in absorbing sound or noise in this study. Glass wool demonstrates relatively better sound energy absorption compared with cotton. In general, soft and porous materials are considered good performance in sound absorption. Denser materials are better at soundproofing or sound blocking. Therefore, glass wool with relatively higher density among the investigated absorptive materials in this study has the greatest sound absorption performance.
  • Publication
    MICROWAVE ABSORPTION ANALYSIS ON HEATED EDIBLE SPIRULINA WITH VARIOUS TEMPERATURES
    ( 2023-05-01)
    Cheng Ee Meng
    ;
    Tan Wei Hong
    ;
    Tan Wee Choon
    ;
    Lim Eng Aik
    This paper discusses the microwave absorption analysis of edible Spirulina by using WR62 and WR90 rectangular waveguides in conjunction with Agilent P-series Vector Network Analyzer (PNA). Heat might lead to the degradation of spirulina. This phenomenon involves the chemical and physical reaction that is associated with the variation of dielectric properties. These properties determine the propagation mechanism of microwaves within the sample or material. Hence, an assessment method to detect a nutrient change in spirulina due to heat is necessary. In this context, a microwave absorption measurement system was developed to study the reflection coefficient, transmission coefficient, and absorption coefficient of Spirulina tablets over temperature. The transmission/Reflection line method is well-known because it is non-destructive and rapid in analyzing chemical and physical properties. In this work, Spirulina tablet is used since it is a popular food supplement that is believed to be able to treat diseases is and good for health. The reflection, transmission, and absorption measurements were conducted on Spirulina from 12.4GHz to 18GHz.
  • Publication
    Numerical analysis on the effect of diluted hydrogen fuel by a fixed amount of supplied hydrogen using a quasi-three-dimensional solid oxide fuel cell model
    (Asian Research Publishing Network (ARPN), 2023)
    Tan Wee Choon
    ;
    Lim Eng Aik
    ;
    Cheng Ee Meng
    ;
    Tan Wei Hong
    ;
    Hamimah Abd Rahman
    Solid oxide fuel cell (SOFC) has excellent fuel flexibility for various fuels. Despite some drawbacks like storage and transportation, hydrogen stands up as the best fuel for SOFC. Hydrogen fuel is diluted non-reactive gas species before it is supplied to the SOFC. In this study, a quasi-three-dimensional SOFC model with real microstructure is used to analyse the effect of the diluted fuel mixture. The hydrogen fuel is diluted with nitrogen and a small amount of steam. The mole amount of hydrogen within fuel mixtures is kept constant. On the other hand, the air that is supplied to the air channel of the SOFC remains unchanged. It is found that the cell that is supplied with the highest concentration of hydrogen has the highest performance due to its high partial pressure of hydrogen within the fuel mixture. Such a high partial pressure promotes a low anode concentration loss. Also, the cell that is supplied with a low hydrogen concentration is unable to benefit from its high average cell temperature as its performance is drained by the low partial pressure of hydrogen within the fuel mixture.
  • Publication
    Numerical analysis of the effect of pore size toward the performance of solid oxide fuel cell
    (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
    Tan Wee Choon
    ;
    Lim Eng Aik
    ;
    Cheng Ee Meng
    ;
    Tan Wei Hong
    The effect of the anode pore size is numerically investigated with the aids of artificial solid oxide fuel cell (SOFC) microstructure information. The standalone effect of the pore size is impossible to be realized by the experimental approach. Additionally, the complete real microstructure information is also limited in the open literature as it required sub-micron 3D imaging equipment. The dusty-gas model is implemented into the developed quasi-3D SOFC model for the gas diffusion in the anode. The model with real microstructure information is successfully validated. The actual anode pore radius of 0.283 Î¼m is artificially replaced with a radius of 0.025, 0.050, 0.250, 0.500, and 2.500 Î¼m. Decrement of area-specific reactant (ASR) for the anode concentration is found with the increment of pore radius. Also, such increment promotes a small increment of ASRs for the anode activation and the anode ohmic loss.
      2  2
  • Publication
    Acoustical simulation and analysis on the resonator muffler
    (Asian Research Publishing Network, 2022-10-01)
    Tan Wei Hong
    ;
    Cheng Ee Meng
    ;
    Lim Eng Aik
    ;
    Tan Wee Choon
    ;
    Amaresh S.G.
    With the modernisation of transport during the period of industrial urbanization, vehicles on the road are increasing, and it brings noise disturbances caused by the internal combustion engine of vehicles. This study involves the acoustical model development and analysis of the vehicle muffler. In this study, the resonator type of muffler is considered, and the transmission loss (TL) is used as the parameter to evaluate the acoustic performance of the muffler. The muffler CAD model is created using Solid works, and the acoustical analysis is conducted using COMSOL Multiphysics. The developed muffler model is tuned several times to obtain the optimum TL. The study yielded a wide range of TL across a range of frequencies. It is found that constrictions to the intake and exhaust pipes generated a higher TL by ~20dB than the original dimensions. Using an acoustic dampener further increases the TL of the muffler with a maximum increase of 18%. The inclusion of an acoustic dampener paired with the reduced diameter of the intake and exhaust pipes resulted in the analytical model generating the highest TL in the resonator muffler.
      3  2
  • Publication
    Improved K-Means Clustering for Initial Center Selection in Training Radial Basis Function Networks
    (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
    Lim Eng Aik
    ;
    Tan Wee Choon
    ;
    Tan Wei Hong
    ;
    Cheng Ee Meng
    Radial Basis Function networks accuracies mainly affected by its center selection from dataset. K-means (KM) clustering is a widely in numerous field for data classification and centers selection. However, initial centers selection poses high impact on KM clustering outcome. It suffers from its immense reliance on the initial centers selection algorithm from the dataset. KM algorithm has been enhanced for its performance from diverse perspectives over the years. Nonetheless, a good balance between quality and efficiency of the centers selected by the algorithm is not attained. To overcome this issue, this paper proposed an improvement on KM clustering algorithm in getting initial centers and reduce its sensitivity to initial centers. This paper introduce the use of improved K-means (KM) clustering that consider the each point distance as probability for selecting the initial centers with radial basis function network (RBFN) training algorithm. The proposed approach uses improved KM for centers selection in RBFN training algorithm shows accuracy improvement in predictions and with simpler network architecture compared to the conventional RBFN. The proposed network called IKM-RBFN was tested against the conventional RBFN, KM-RBFN, back-propagation neural network and long short-term memory neural network in FOREX EURUSD pair price predictions. The results are compared to proposed method on its root mean square error (RMSE) and mean absolute error (MAE) results. The proposed method shows promising results in improving RMSE accuracy over 20% in compared to other tested networks.
      5
  • Publication
    Microwave Dielectric Properties and Absorption Analysis for Seashells Through Transmission-Reflection Method Using Waveguides
    (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
    Cheng Ee Meng
    ;
    Tan Wei Hong
    ;
    Tan Wee Choon
    ;
    Lim Eng Aik
    This work is aim to investigate microwave dielectric behavior and microwave absorption of seashells through transmission-reflection method using waveguides. Microwave dielectric and absorption characteristic are judged through the measured reflection and transmission coefficient via two waveguides in conjunction with P-series network analyzer (PNA) from 8.2 GHz to 18 GHz. Anadara granosa seashells are collected in this work for comparison. The measurement was conducted in various temperature, i.e. 35 â„ƒ, 50 â„ƒ and 60 â„ƒ. The sample was prepared in specified dimension, according to the operating frequency range. Results in this study reveals absorption coefficient is function of frequency and dimension. As the frequency increase, the | S11 | decrease whereas the | S21 | increase. Better absorption was demonstrated by seashells in room temperature than the heated seashell.
      2  2