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George Town, Malaysia

Ahmad N.,UniversitiSains Malaysia
Materials Science Forum | Year: 2015

he influence of alginate concentration on the diametral tensile strength (DTS) of hydroxyapatite (HAp) block was investigated. Alginate solution with concentration of 1%, 3% and 5% was prepared through neutral extraction from cultivated sargassum polycystum brown seaweed obtained from Semporna, Sabah, Malaysia. Commercially available HAp powder was pressed uniaxially at 3 MPa to obtain the HAp block. The HAp block was then sintered at 900°C. The sintered HAp block was then immersed in alginate solution under vacuum condition for 24 hours. DTS value of the HAp block decreases with increasing alginate concentration. Porosity measurement increases with the increase in alginate concentration used. The decrease in the DTSvalue with increasing alginate concentration is due to the higher viscosity at higher alginate concentration and thus limited the amount of alginate being penetrate into the HAp block. © (2015) Trans Tech Publications, Switzerland.

Damavandinejadmonfared S.,UniversitiSains Malaysia
Proceedings - 2012 IEEE 8th International Conference on Intelligent Computer Communication and Processing, ICCP 2012 | Year: 2012

In this paper, a new method for face recognition in video surveillance is proposed. Local mean-based k-nearest centroid neighbour (LMKNCN) is a recently proposed method for classifying data which has been proven to be more appropriate than other classifiers such as k-nearest neighbour (KNN), K-Nearest Centroid Neighbour (KNCN), and local mean-based k-nearest neighbour (LMKNN). Kernel Entropy Component Analysis is a new extension of 1-D PCA-based feature extractions methods enhancing the performance of PCA-based methods. In the proposed method in this paper, LMKNCN is used as a classifier in KPCA method. Moreover, the Extensive experiments on surveillance camera faces database (SCfaces) and Head Pose Image database reveal the significance of the proposed method. © 2012 IEEE.

Jahani S.,UniversitiSains Malaysia | Samsudin A.,UniversitiSains Malaysia
Applied Mechanics and Materials | Year: 2013

The number theory based cryptography algorithms are the most commonly used publickeycryptosystems. One of the fundamental arithmetic operations for such systems is the large integer multiplication. The efficiency of these cryptosystems is directly related to the efficiency of this large integer multiplication operation. Classical multiplication algorithm and Karatsubamultiplication algorithm, and their hybrid,are among the most popular multiplication algorithms used for this purpose. In this paper, we propose a hybrid of Karatsuba and a classicalbased multiplication algorithm, enhanced by a new number representation system. The new number representation, known as "Big-Digits",is used to carry out the sub-multiplication operation in the new multiplication algorithm. Big-Digits has a compact representation with lower Hamming weight. As the result, the number of sub-multiplication operations for the multiplication algorithm that is based on the Big-Digits representation is significantly reduced. Our results show that the proposed multiplication algorithmis significantly faster than the classical, Karasuba and the hybrid of Karatsuba-Classical multiplication algorithms within the implementation domain of the publickey cryptography. © (2013) Trans Tech Publications, Switzerland.

Nabihah M.F.,UniversitiSains Malaysia | Shanmugan S.,UniversitiSains Malaysia
Digest Journal of Nanomaterials and Biostructures | Year: 2016

Beryllium oxide (BeO) nanoparticles were synthesized by polyacrylamide gel route followed by calcination at 700°C and 800° C and examined their structural behaviour by X-ray diffraction (XRD). The structural parameters such as dislocation density, residual stress, lattice strain, texture coefficient, lattice parameter and bond length were calculated from XRD data and discussed. The calculated crystallite size was in nanometer scale (<70 nm) and reduced when calcined at 800°C. Dislocation density was changed with respect to orientations and observed low value for (100) orientated phase when calcined at 700°C. Residual stress analysis evidenced the formation of compressive stress and dominated for calcined BeO nanoparticles. Calcination temperature did not much influence in changing the Be-O bond length. The synthesis of preferentially (002) oriented BeO nanoparticles were confirmed by texture coefficient analysis. Transmission Electron Microscopy (TEM) was attested the formation of nano particles with ellipsoid-like shape and agreed with XRD results. Stoichiometric BeO nano particles were confirmed by EDX spectra. © 2016, Inst Materials Physics. All right reserved.

Andas J.,University Technology of MARA | Adam F.,UniversitiSains Malaysia
Materials Today: Proceedings | Year: 2016

In this study, silver nanoparticles (AgNP/SiO2) with an average diameter of 25 nm were successfully fabricated using silica rice husk as support via a simple yet cheap sol-gel route at room temperature. The synthesized AgNP/SiO2 was characterized by several spectroscopic methods such as FTIR, SEM/EDX, XRD, N2 adsorption-desorption and TEM analyses. FTIR and EDX analyses showed the successful inclusion of silver into the silica framework. Preservation of the amorphous nature of silica in AgNP/SiO2 was confirmed from the high angle powder XRD analysis. High mesoporosity of AgNP/SiO2 (BET surface area = 514 m2g-1 and pore volume = 0.50 ccg-1) was clearly evidenced from the N2-sorption studies. Well-dispersion of spherical Ag nanoparticles was observed through the TEM investigation. This research proves the successful conversion of uneconomical biomass into discreet AgNP/SiO2 via a facile and novel sol-gel method. © 2016 Elsevier Ltd.

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