Ho Li Ngee, Dr.
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/39207
2024-03-28T12:53:57ZInfluence of Sintering Temperature on Crystallization Behavior of Cordierite synthesized from Non-Stoichiometric Formulation
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/69173
Influence of Sintering Temperature on Crystallization Behavior of Cordierite synthesized from Non-Stoichiometric Formulation
K. K., Eing; Banjuraizah, Johar; Li-Ngee, Ho; Zabar, Y.
Cordierite body with formulation of non-stoichiometric composition (2.5 MgO. 1.8 Al2O3. 5 SiO2) was synthesized using conventional techniques with standard raw materials. The sintering and crystallization behavior of the compositions was observed by Differential Thermal Analysis and Thermogravimetric Analysis (DTA/TG). The sequence of reaction and phase transformation was analyzed using X-ray Diffraction (XRD) technique and Rietveld structural refinement after sintering the samples at different temperature regarding the information from the DTA. The Scanning electron microscopy (SEM) was employed for morphology analysis. The DTA curve shows the crystallization temperature, Tc occur at 1259°C.Rietveld quantitative phase analysis results reveal that α phase Cordierite constitutes up to 96.4 wt% when the samples was sintered for 2 hours at the optimal temperature of 1375°C. The SEM micrograph revealed that the sample was heat treated at 1375°C obtained densified body with well alignment of crystal structure.
Link to publisher's homepage at https://www.matec-conferences.org/
2016-01-01T00:00:00ZCopper-filled electrically conductive adhesives with enhanced shear strength
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/39299
Copper-filled electrically conductive adhesives with enhanced shear strength
Ho, Li Ngee, Dr.; Hiroshi, Nishikawa
In this study, the effects of diethyl carbitol (diluent) and tertiary amines on the electrical, mechanical, and rheological properties of the Cu-filled polyurethane-based electrically conductive adhesives (ECAs) were investigated. Significant difference could be observed in the electrical resistivity and shear strength of ECA prepared with different amount of diethyl carbitol. Reduced electrical resistivity was found in ECAs prepared with addition of tertiary amines, but no obvious change was observed in the shear strength of the ECA joint. Rheological property of the ECA paste was investigated in order to understand the correlation of the viscosity of ECA paste and electrical resistivity and shear strength of ECA joint. Results revealed that decrease in viscosity of the ECA paste reduced electrical resistivity and enhanced shear strength of ECA joint. A Cu-filled polyurethane-based ECA with considerably low electrical resistivity at the magnitude order range of 10-3 Ωcm, and significantly high shear strength (above 17 MPa) could be achieved.
Link to publisher's homepage at http://www.asminternational.org/
2014-09-01T00:00:00ZA simple one-step anodising method for the synthesis of ordered porous anodic alumina
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/34862
A simple one-step anodising method for the synthesis of ordered porous anodic alumina
Voon, Chun Hong; Mohd Nazree, Derman, Dr.; Uda, Hashim, Prof. Dr.; Khairel Rafezi Ahmad, Dr.; Ho, Li Ngee
Porous anodic alumina (PAA) has been produced on aluminium substrate by single-step anodising at 50 V in 0.3 M oxalic acid at 15°C for 60 min. The highly ordered pore and cell structure was achieved by subjecting the PAA to oxide dissolution treatment in a mixture of chromic and phosphoric acids. The nanostructure prior and post-oxide dissolution treatment was examined under scanning electron microscope. It was found that the oxide dissolution treatment improves the regularity of the cell and pore structure significantly. Uniform closely packed honeycomb structure of PAA is obtained. The uniformities of pore diameter and interpore distance are also enhanced. Compared to the PAA prior treatment, it was noticed that the pore diameter of the post-treatment PAA increases.
Link to publisher's homepage at http://www.tandfonline.com
2014-01-01T00:00:00ZAdsorption behavior of cationic and anionic dyes onto acid treated coconut coir
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/34860
Adsorption behavior of cationic and anionic dyes onto acid treated coconut coir
Ong, Soon An, Dr.; Ho, Li Ngee, Dr.; Wong, Yee Shian; Asraff, Zainuddin
The adsorption of Methylene Blue (MB) and Acid Orange 7 (AO7) from aqueous solutions by acid treated coconut coir was investigated under laboratory conditions to assess its potential in removing cationic and anionic dyes. The acid treated coconut coir exhibited better adsorption capacity in cationic dye MB than anionic dye AO7 and the data obtained can be well described by both Langmuir and Freundlich isotherm models. According to the Langmuir isotherm model, the maximum adsorption capacities of MB and AO7 onto acid treated coconut coir were 121 mg/g and 10 mg/g, respectively. The adsorption behavior of MB and AO7 onto acid treated coconut coir was analyzed with first-order Lagergren model and pseudo-second order model.
Link to publisher's homepage at http://www.tandfonline.com/
2013-09-01T00:00:00Z