Khor Shing Fhan
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Khor Shing Fhan
Official Name
Shing Fhan, Khor
Alternative Name
Khor, S. F.
Fhan, Khor Shing
Shing, Fhan Khor
Khor, Shing F.
Shing Fhan, Khor
Main Affiliation
Scopus Author ID
35242874900
Researcher ID
W-7216-2019

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  • Publication
    Formation of bio-based derived dicalcium silicate ceramics via mechanochemical treatment: physical, XRD, SEM and FTIR analyses
    ( 2023-07)
    Siti Nur Hazwani Yunus
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Nur Hazlinda Jakfar
    ;
    Cheng Ee Meng
    ;
    Emma Ziezie Mohd Tarmizi
    ;
    Zainal Abidin Talib
    Beta-dicalcium silicate plays an important role in modern technology, but its tendency for polymorphic transformation results in the dusting phenomenon, is a major challenge. Therefore, mechanochemical treatment is used to reduce the particle size to retain the stability of the polymorph. In this study, pure dicalcium silicate ceramics of β-monoclinic structure with P 121/c1 space group were synthesized using calcium oxide and silicate powders derived from calcined eggshells and rice husks, respectively. The powders were mixed in a 2:1 molar ratio by mechanochemical treatment and heat-treated in the air at temperatures ranging from 900°C to 1100°C for 2 h. The results reveal that pure betadicalcium silicate formed at 1100°C without adding stabilizers. The properties of the pristine and sintered bodies were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). SEM revealed that the grain and pore sizes increase with rising sintering temperatures. FTIR spectra indicate the existence of Si-O bonds in -4 4 SiO tetrahedrons on all the samples. The sample sintered at 1000°C attains the lowest bulk density (1.2463 g/cm3), whereas the apparent porosity is the highest (62.5%). The reason for this trend is due to the decomposition of carbonate into CO2 gas. The densification onset for the sample sintered at 1100°C as the bulk density rises and grain size achieves 6.06 μm. This study further explains the effect of sintering temperatures on the physical, structural, and morphological properties of Ca2SiO4 which would also be useful for further optimization of its use.
  • Publication
    Dielectric spectroscopy technique for carbohydrate characterization of fragrant rice, brown rice and white rice
    ( 2017-11-20)
    Cheng Ee Meng
    ;
    Kok Yeow You
    ;
    Lee KimYee
    ;
    Abbas Z.
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Khor Shing Fhan
    ;
    Zulkarnay Zakaria
    ;
    Lee Y.S.
    This study was conducted to investigate the feasibility of microwave dielectric spectroscopic technique in characterizing commercial rice due to different level of moisture content. There are some unethical rice industry runner mixes good qualities of rice which can be sold at high price with low cost and quality of rice to maximize profit. It causes fraudulency in business and great lost in term of money to nation who take rice as staple food. It happens frequently in Asian country which is active in agricultural activities. This technique is implemented using Keysight E8362B network analyzer in conjunction with an Keysight 85070E dielectric probe ranging from 200 MHz to 10 GHz. The samples of study are commercially available at market, namely fragrant rice, white rice, and brown rice, respectively. These are the popular and favorite rice for Malaysian due its delicacy and affordable price. Nutrient level for fragrant rice, white rice, and brown rice in terms of protein, moisture, carbohydrate and fat are different and unique. It leads to various electromagnetic responses toward frequency. Dielectric and reflection measurement were conducted to characterize these rice. The presence of polar and non-polar molecules in nutrient of rice causes variation of dielectric and reflection behavior over the operating frequency range.
  • Publication
    Morphological and optical properties of porous hydroxyapatite/cornstarch (HAp/Cs) composites
    ( 2020-01-01)
    Beh C.Y.
    ;
    Cheng Ee Meng
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Mohd Tarmizi E.Z.
    ;
    Eng S.K.
    ;
    Mohd Shukry Abdul Majid
    ;
    Mohd Ridzuan Mohd Jamir
    ;
    Khor Shing Fhan
    ;
    Ahmad Saad F.S.
    This paper presents the correlation between the morphological characteristics and the diffuse reflectance (optical properties) of the porous hydroxyapatite/cornstarch (HAp/Cs) composites with various starch proportions (30, 40, 50, 60, 70, 80 and 90 wt%). The porous composites were measured via SEM and enhanced by image processing to find the average pore size, strut width, and average surface roughness. The average porosity of the porous composites was measured using liquid displacement method. The diffuse reflectance spectroscopy was implemented to investigate the diffuse reflectance and the corresponding optical band gap energy of the porous composites in the 500e900 nm range. A relationship between morphological characteristics and diffuse reflectance properties were established using Pearson's correlation coefficient. The findings of the study depict that a strong correlation can be noticed between optical band gap energy with porosity, pore sizes and surface roughness of the porous composites. Meanwhile, the strong correlations between the diffuse reflectance spectral gradient with surface roughness can be observed. The moderate correlations can be observed between the diffuse reflectance spectral gradient with pore sizes and strut width of the porous composites.
      2
  • Publication
    Complex Impedance and Modulus Analysis on Porous and Non-Porous Scaffold Composites Due to Effect of Hydroxyapatite/Starch Proportion
    ( 2023-01-01)
    Beh C.Y.
    ;
    Cheng Ee Meng
    ;
    Tan X.J.
    ;
    Mohd Nasir N.F.
    ;
    Mohd Shukry Abdul Majid
    ;
    Mohd Ridzuan Mohd Jamir
    ;
    Khor Shing Fhan
    ;
    Lee K.Y.
    ;
    Che Wan Sharifah Robiah Mohamad
    This study aims to investigate the electric responses (complex modulus and complex impedance analysis) of hydroxyapatite/starch bone scaffold as a function of hydroxyapatite/starch proportion and the microstructural features. Hence, the non-porous and porous hydroxyapatite/starch composites were fabricated with various hydroxyapatite/starch proportions (70/30, 60/40, 50/50, 40/60, 30/70, 20/80, and 10/90 wt/wt%). Microstructural analysis of the porous hydroxyapatite/starch composites was carried out by using scanning electron microscopy. It shows that the formation of hierarchical porous microstructures with high porosity is more significant at a high starch proportion. The complex modulus and complex impedance analysis were conducted to investigate the electrical conduction mechanism of the hydroxyapatite/starch composites via dielectric spectroscopy within a frequency range from 5 MHz to 12 GHz. The electrical responses of the hydroxyapatite/starch composites are highly dependent on the frequency, material proportion, and microstructures. High starch proportion and highly porous hierarchical microstructures enhance the electrical responses of the hydroxyapatite/starch composite. The material proportion and microstructure features of the hydroxyapatite/starch composites can be indirectly reflected by the simulated electrical parameters of the equivalent electrical circuit models.
      4
  • Publication
    Low frequency dielectric and optical behavior on physicochemical properties of hydroxyapatite/cornstarch composite
    ( 2021-10-15)
    Beh C.Y.
    ;
    Cheng Ee Meng
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Khor Shing Fhan
    ;
    Eng S.K.
    ;
    Mohd Shukry Abdul Majid
    ;
    Mohd Ridzuan Mohd Jamir
    ;
    Lee K.Y.
    An investigation on relationship among the physicochemical, optical and dielectric properties of the hydroxyapatite/cornstarch (HA/Cs) composites with the starch proportion of 30, 40, 50, 60, 70, 80 and 90 wt% is presented in this work. The HA/Cs composites have been characterized via FTIR, XRD, DRS and impedance analyzer. This work depicts that the strong interaction is exhibited between the hydroxyapatite nanoparticles and starch as the starch proportion increases. This increment trend results in the higher crystallinity of the HA/Cs composites. The highly crystallized HA/Cs with hydroxyapatite nucleation center presents low optical properties (diffuse reflectance and optical band gap energy). The HA/Cs composite with 80 wt% starch proportion (H2C8) show higher dielectric properties (dielectric constant, loss factor and conductivity) due to the stronger interfacial interaction and close-packed HA/Cs crystalline structure. The relationship among the physicochemical, optical and dielectric properties of the HA/Cs composite is studied in this work for potential of instrumentation design.
      2  1
  • Publication
    Regression Analysis of the Dielectric and Morphological Properties for Porous Nanohydroxyapatite/Starch Composites: A Correlative Study
    ( 2022-05-01)
    Beh C.Y.
    ;
    Cheng Ee Meng
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Mohd Tarmizi E.Z.
    ;
    Mohd Shukry Abdul Majid
    ;
    Mohd Ridzuan Mohd Jamir
    ;
    Lee K.Y.
    ;
    Khor Shing Fhan
    This paper aims to investigate the dielectric properties, i.e., dielectric constant (ε′), dielectric loss factor (ε″), dielectric tangent loss (tan δ), electrical conductivity (σ), and penetration depth (Dp), of the porous nanohydroxyapatite/starch composites in the function of starch proportion, pore size, and porosity over a broad band frequency range of 5 MHz–12 GHz. The porous nanohydroxyapatite/starch composites were fabricated using different starch proportions ranging from 30 to 90 wt%. The results reveal that the dielectric properties and the microstructural features of the porous nanohydroxyapatite/starch composites can be enhanced by the increment in the starch proportion. Nevertheless, the composite with 80 wt% of starch proportion exhibit low dielectric properties (ε′, ε″, tan δ, and σ) and a high penetration depth because of its highly interconnected porous microstructures. The dielectric properties of the porous nanohydroxyapatite/starch composites are highly dependent on starch proportion, average pore size, and porosity. The regression models are developed to express the dielectric properties of the porous nanohydroxyapatite/starch composites (R2 > 0.96) in the function of starch proportion, pore size, and porosity from 1 to 11 GHz. This dielectric study can facilitate the assessment of bone scaffold design in bone tissue engineering applications.
      1  18
  • Publication
    Microwave reflection measurement on thermal degradation of animal and vegetable oils
    ( 2022-10-01)
    Cheng Ee Meng
    ;
    Shahriman Abu Bakar
    ;
    Tan W.H.
    ;
    Mohd Afendi Rojan
    ;
    Khor Shing Fhan
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Robiah M.C.W.S.
    ;
    You K.Y.
    In this work, the reflection measurement on animal and vegetable oils due to different heating temperature was conducted using Agilent E8362B slim probe in conjunction with Agilent E8362B PNA Network Analyzer. The effect of thermal degradation on measured reflection efficient (Γ) is investigated. Many chemical processes are occurred when edible oils are heated during frying process. The thermal degradation products, i.e., volatile and non-volatile chemical compounds are generated. The generated volatile chemical compounds are dangerous to human health. Products of thermal degradation of animal and vegetable oils can be carcinogenic. On the other hand, it may cause diabetes, atherosclerosis, Alzheimer’s and Parkinson’s diseases, coronary heart disease, sudden cardiac death, and systemic vasculitis. Slim probe and open ended coaxial sensor are implemented to measure the reflection coefficient of the cooking oils. The fresh animal fats and vegetable oils are commercially available in local market. Five types of cooking oil (i.e. corn oil, olive oil, palm oil, sunflower oil and walnut oil) were measured at the temperature of 60ºC, 80ºC and 100 ºC for the frequency range of 3 GHz to 8GHz. When the oil is subjected to thermal degradation during heating, the chemical chain of oil will be altered and resulting in physical and internal properties change. It is the key element that led to the variation of Γ. Γ is function of physical-chemical properties of cooking oil that implying the oil quality. In reflection measurement, there are different noticeable results which indicates the used and fresh cooking oil and the effect of heating period
      36  2
  • Publication
    Dielectric properties of Nephelium Lappaceum tropical wood
    ( 2020-03-25)
    Khor Shing Fhan
    ;
    Cheng Ee Meng
    ;
    Banjuraizah Johar
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Zaizul M.A.
    ;
    Wan Azani Wan Mustafa
    ;
    Nik Noriman Zulkepli
    ;
    Dahham O.S.
    Dielectric properties of rambutan wood (Nephelium Lappaceum) were investigated in three anisotropic directions, namely miters-cut, cross-cut, and rib-cut. Dielectric constants and dielectric loss factors were measured at ambient temperatures by using an impedance analyzer. The dielectric constant decreased as frequency increased from 4 to 1 MHz. Among the wood specimens, the rib-cut direction has the lowest dielectric constant, while the cross-cut direction has the highest value. A dielectric dispersion occurred within frequencies 100 Hz to 10 kHz, which corresponding to a relaxation peak as observed on dielectric loss factor spectra. The relaxation peak value of the dielectric loss factors shifted towards higher frequencies in the sequence of rib-cut, miters-cut, and cross-cut specimen. Above 500 Hz, the cross-cut specimen has the highest value conductivity than others. Generally, these variations were subjected to the anatomical structure in the wood, such as parenchyma, ray cell, vessel cell, and fiber cell.
      41  2
  • Publication
    Synthesis of sustainable binary Calcium monosilicate ceramics from bio-waste: effect of sintering temperature on microstructure and electrical properties
    (Universiti Malaysia Perlis (UniMAP), 2023-01)
    N. H. Jakfar
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    S. N. H. Mohd. Yunus
    ;
    Cheng Ee Meng
    ;
    E. Z. M. Tarmizi
    ;
    Z. A. Talib
    This study was conducted to synthesise calcium monosilicate ceramics using rice husks and raw eggshells and investigated the effect of sintering temperature on the physical, microstructure and electrical properties of the final product. The high content of calcium and silicon in eggshells and rice husks, respectively promote the use of waste materials in the production of calcium monosilicates by mixing in a molar ratio 1CaO:1SiO2 and fired at different sintering temperatures for 2 hours with a heating rate of 10°C/min. A good correlation between sintering temperature, structural, microstructure, and electrical properties of calcium silicate was observed. The structural and morphological evolutions were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with electron dispersive X-ray analysis (EDX). XRD analysis showed that the main crystalline phases of synthesised calcium monosilicate are pseudowollastonite (ICSD 98- 005-2598) at 1250°C, and the phases of SiO2 also exist in different types of minerals. Besides, a small amount of larnite, Ca2SiO4 was traced at 1100°C and 1200°C. Fourier Transforms Infrared (FTIR) spectra showed the presence of characteristic functional groups in the precursor powder. In Nyquist plots, the summit frequency of the dominant arc decreases with increasing sintering temperatures. It may be attributed to the co-effect of the grain size and pore. A larger value of impedance at a lower frequency suggests an essential role of boundaries in governing the electrical properties of the sintered ceramics. As the sintering temperature increases, the microstructure of the sintered samples becomes denser while conductivity performance decreases. This is due to the reduction of particle interfaces and charge transfer.
      1  17
  • Publication
    Dielectric Properties of Hydrothermally Modified Potato, Corn, and Rice Starch
    ( 2022-06-01)
    Beh C.Y.
    ;
    Cheng Ee Meng
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Mohd Tarmizi E.Z.
    ;
    Khor Shing Fhan
    ;
    Mohd Shukry Abdul Majid
    ;
    Lee K.Y.
    ;
    Mohd Ridzuan Mohd Jamir
    The effect of starch granule sizes, shapes, composition, and frequency on the dielectric properties (dielectric constant, loss factor, and conductivity) of native and hydrothermally modified starches (potato, corn, and rice starch) are investigated in this work. Dielectric properties are determined from 5 Hz to 5 GHz. The modified starches exhibit lower dielectric properties than the native starches from 5 Hz to 5 GHz due to the disruption of the native polysaccharide’s molecular arrangement. The modified potato starch shows the highest loss factor (208.12 at 50 Hz and 19.95 at 500 Hz) and stable conductivity (~5.33 × 10−7 S/m at 50 Hz and 500 Hz) due to the larger continuous network structure after hydrothermal modification. The rice starch shows the largest difference in dielectric constant (47.30%) and loss factor (71.42%) between the modified form and native form in the frequency range of 5 MHz–5 GHz. This is due to the restriction of dipole motions in the closely packed structure after hydrothermal modification. The findings indicate that the quality of starch modification can be characterized by dielectric properties for assisting starch-based plastic production’s design.
      2