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Kuala Lumpur, Malaysia

You K.Y.,University of Technology Malaysia | Lee C.Y.,University of Technology Malaysia | Then Y.L.,University of Technology Malaysia | Chong S.H.C.,Tunku Abdul Rahman College | And 3 more authors.
IEEE Sensors Journal | Year: 2013

A handheld microwave reflectometer-sensor system is developed to operate from 1.35 to 1.95 GHz and used to measure volumetric and gravimetric moisture content in various types of soils from 0% to 45%. A small monopole driver from coaxial line is buried into the soil, and its reflected voltage is measured and correlated with corresponding soil moisture content obtained from oven dying method. The measured reflected voltage is dependent on the nonlinear change of dielectric properties of the soil with the moisture content. © 2001-2012 IEEE. Source

Teh G.B.,Tunku Abdul Rahman College | Wong Y.C.,Swinburne University of Technology | Wang J.,Swinburne University of Technology | Tan S.G.,University Tunku Abdul Rahman | Samini B.,University Tunku Abdul Rahman
Materials Science Forum | Year: 2010

Magnetoplumbite-type (M-type) strontium ferrite particles with two stoichiometric ratios (SrFexO19; x = 9.2 and 11.6) have been synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. The prepared samples were characterized using x-ray diffractometry (XRD), thermogravimetric analysis (TGA), photoluminescence (PL) spectrophotometry, field emission scanning electron microscopy (FESEM), energy dispersive x-ray spectrometry (EDS) and superconductivity quantum interference device magnetometry (SQUID). X-ray powder diffraction patterns showed that the samples were single-phase with the space group of P63/mmc and cell parameter values of a = 5.88 Å and c = 23.03 - 23.04 Å. EDS results confirmed the composition being mainly of M-type SrFe12O 19. The photoluminescence property of strontium ferrite was examined at excitation wavelength of 260 - 290 nm and significant PL emission peaks centered at 334 nm were detected. Both as-prepared strontium ferrites exhibited significant oxygen vacancies which were detectable via TGA where the sample with the Sr/Fe ratio of 1:11.6 exhibited the highest oxygen vacancies in its structure. © (2010) Trans Tech Publications. Source

Yip M.W.,Tunku Abdul Rahman College | Barnes S.,University of Warwick
Advanced Materials Research | Year: 2013

The objective of this research was to develop a new form of clad layer by producing a Silicon Carbide (SiC) particle reinforce Metal Matrix Composite (MMC) using the iron based alloys as the matrix material. A 1.2kW continuous wave CO2 laser was used in this research. A gravity feed system was used with one powder feed which contained different percentages of SiC particles and iron based powder. Experimental results showed that the decomposition of SiC particles was observed and only a few SiC particles were found in the clad matrix. High micro hardness values were found in the SiC clad which were in excess of 1000 HV. However, most of the SiC were evaporated which created porosity in the melt pool. Therefore, blown powder technique is recommended for overcome this problem. © (2013) Trans Tech Publications, Switzerland. Source

Ooi J.,Tunku Abdul Rahman College | Wang X.,University Tunku Abdul Rahman | Lim Y.P.,University Tunku Abdul Rahman
50th Annual Conference of the British Institute of Non-Destructive Testing 2011, NDT 2011 Held in conjunction with the Materials Testing Exhibition, MT 2011 | Year: 2011

Portal axle unit is a gearbox unit installed on every end axles of the vehicle. They are installed to the vehicle to give higher ground clearance to enable vehicle to go over large obstacle when driving in off-road conditions. Shafts designed must be exceptionally tough and lightweight to improve the overall performance of the portal axle unit. In this paper, the design of the hollow shaft with rib attached at each end is analysed in detail. Selected parameters of the rib are studied to further optimize the proposed shaft design. Finite element method (FEM) is employed to simulate stress analysis on the shaft models. Torque delivered from the engine to the shaft and the shaft's weight is considered in the FEM simulation. The stress and weight reduction results are calculated for optimum shaft, existing shaft and solid shaft for comparison. The optimum model of the shaft shows slight improvement over the existing shaft. © (2011) by the British Institute of Non-Destructive Testing. All rights reserved. Source

Ting T.O.,Xian Jiaotong - Liverpool University | Ting H.C.,Tunku Abdul Rahman College | Lee S.,Xian Jiaotong - Liverpool University
Lecture Notes in Electrical Engineering | Year: 2013

This paper proposes an effective Segregated Lightweight Dynamic Rate Control Scheme (SLDRCS) over the internet. Based on the feedback analysis of the current approaches, we found that the indicator of the congestion is only the queue length. It only captures a partial indicator of delay and loss in feedback mechanism. This may result in an ineffective way in controlling the network when congestion control occurs. Therefore, we suggest multiple congestion indicators to adapt inside this scheme to fully control the average delay and loss from bidirectional of sender to receiver. The behavior of next event packet being control using discrete event simulation tool with First Come First Serve (FCFS) scheduling policy and we code this algorithm into C programming language. Through the simulation results, our Segregated Lightweight Dynamic Rate Control Scheme (SLDRCS) guaranteed high improvement in packet drop and average delay under various congestion level and traffic load conditions compare with the current approach. © 2013 Springer Science+Business Media Dordrecht. Source

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