UniMAP RIS :: Browsing Publications 2017 by Issue Date

Publication

A highly efficient immobilized ZnO/Zn photoanode for degradation of azo dye Reactive Green 19 in a photocatalytic fuel cell

( 2017-01-01)

Lee S.L.

;

Ho L.N.

;

Ong S.A.

;

Wong Y.S.

;

Voon C.H.

;

Khalik W.F.

;

Yusoff N.A.

;

Nordin N.

Photocatalytic fuel cell (PFC) is a potential wastewater treatment technology that can generate electricity from the conversion of chemical energy of organic pollutants. An immobilized ZnO/Zn fabricated by sonication and heat attachment method was applied as the photoanode and Pt/C plate was used as the cathode of the PFC in this study. Factors that affect the decolorization efficiency and electricity generation of the PFC such as different initial dye concentrations and pH were investigated. Results revealed that the degradation of Reactive Green 19 (RG19) was enhanced in a closed circuit PFC compared with that of a opened circuit PFC. Almost 100% decolorization could be achieved in 8 h when 250 mL of 30 mg L−1 of RG19 was treated in a PFC without any supporting electrolyte. The highest short circuit current of 0.0427 mA cm−2 and maximum power density of 0.0102 mW cm−2 was obtained by PFC using 30 mg L−1 of RG19. The correlation between dye degradation, conductivity and voltage output were also investigated and discussed.

Publication

Management practices of disabled workers in an organization under the law in Malaysia

( 2017-01-01)

Hirwan Jasbir Jaafar

;

Harlida Abdul Wahab

;

Nurli Yaacob

The right to work has been recognized through article 23(1) of the Universal Declaration of Human Rights 1948. According to "World Health Survey 2010", 10 percent of Malaysia's population of 28 million or 2.8 million, are people with disabilities (PWDs). It indicates that nearly three million citizens of Malaysia are PWDs and this can surely influence the economic landscape of the country. This article discusses the major problem confronted by PWDs in the area of employment, particularly the practice of the organization in managing the rights of disabled employees. The purposes of this paper are: (1) to identify the rights of disabled employees according to Malaysian law; (2) to identify organization's practices in managing the rights of the disabled employees; and (3) to recommend some improvement to the existing laws for the protection of disabled employees' rights in Malaysia. In order to accomplish these objectives, socio-legal research was the approach used that involved social issues as well as problems relating to the community. The issues studied are the practices of the organization that employs workers with disability in ensuring their rights are in accordance with the Persons with Disabilities Act 2008 (the Act). These involved three aspects namely the requirement on wages, opportunity for promotion, and environment at work. The study revealed that the requirement on wages was fulfilled and in accordance with the Act but not in the other two aspects. On this account, two suggestions are proposed to ensure the disabled employees are getting proper protection at the work place namely the amendment to the definition of disabled employees and insertion of penalty provision in the case of violation of the Act. With this improvement, all parties especially the employers or organizations will understand and acknowledge the needs of disabled employees which accordingly would ensure an efficient enforcement of the law.

Publication

Sequential biodegradation of complex naphtha hydrocarbons under methanogenic conditions in two different oil sands tailings

( 2017-01-01)

Mohamad Shahimin M.F.

;

Siddique T.

Methane emissions in oil sands tailings ponds are sustained by anaerobic biodegradation of unrecovered hydrocarbons. Naphtha (primarily C6–C10; n- iso- and cycloalkanes) is commonly used as a solvent during bitumen extraction process and its residue escapes to tailings ponds during tailings deposition. To investigate biodegradability of hydrocarbons in naphtha, mature fine tailings (MFT) collected from Albian and CNRL tailings ponds were amended with CNRL naphtha at ∼0.2 wt% (∼2000 mg L−1) and incubated under methanogenic conditions for ∼1600 d. Microbial communities in both MFTs started metabolizing naphtha after a lag phase of ∼100 d. Complete biodegradation/biotransformation of all n-alkanes (except partial biodegradation of n-octane in CNRL MFT) followed by major iso-alkanes (2-methylpentane, 3-methylhexane, 2- and 4-methylheptane, iso-nonanes and 2-methylnonane) and a few cycloalkanes (derivatives of cyclopentane and cyclohexane) was observed during the incubation. 16S rRNA gene pyrosequencing showed dominance of Peptococcaceae and Anaerolineaceae in Albian MFT and Anaerolineaceae and Syntrophaceae in CNRL MFT bacterial communities with co-domination of Methanosaetaceae and “Candidatus Methanoregula” in archaeal populations during active biodegradation of hydrocarbons. The findings extend the known range of hydrocarbons susceptible to methanogenic biodegradation in petroleum-impacted anaerobic environments and help refine existing kinetic model to predict greenhouse gas emissions from tailings ponds.

Publication

Synthesis of silicon carbide nanowhiskers by microwave heating: Effect of heating duration

( 2017-01-01)

Kahar S.

;

Voon C.

;

Lee C.

;

Gopinath S.

;

Arshad M.

;

Lim B.

;

Foo K.

;

Hashim U.

SiC nanowhiskers (SiCNWs), dueto their unique properties such as high thermal stability, high strength, high thermal conductivity and large band gap, lead to a wide range of applications. In this article, synthesis of SiCNWs was performedby using microwave heating. Silica and graphite in the ratio of 1:3 were mixed in an ultrasonic bath, dried on a hotplate and cold pressed uniaxially into a pellet die. The pellets were heatedbyusingalaboratory microwave furnaceto 1400 °C witha heating rate of 20 °C min-1and heated for 20,40and60 min. Characterizationsof the as synthesized SiCNWs were done tostudy the effect ofheating duration onthe morphology and properties of SiCNWs. A time of 40 min was foundto bethe most ideal heating duration for the synthesisof SiCNWs. β-SiC appeared as the only phaseinthe x-ray diffraction pattern for SiCNWs formed byusing40and 60 min of heating duration with no traces of unreacted silica and graphite. Field emission scanning electron microscopy imaging confirmed thatnotrace of graphiteor silica was present in SiCNWs synthesized by a heating duration of 40 and 60 min. Energy dispersive x-ray spectroscopy analysis revealed that only elemental C and Siwere present for SiCNWs synthesizedat 40and60 min. Meanwhile, photoluminescence spectroscopy indicated the presence of single phase β-SiC peakat 440 nmwas associated with band gap of 2.8 eV. Absorption bands of Si-C bond were detected at 802.4 cm-1 in the spectra of fourier transform infrared analysis. SiCNWs produced byheatingat40 and 60 min have high thermal stability with weight loss lower than 6%. A simple process that involved two steps of ultrasonic mixing and microwave heating of graphite and SiO2 is proposed as a new route for the synthesisof SiCNWs.

Publication

Measurement of dielectric properties of textile substrate

( 2017-01-01)

Rahim H.A.

;

Malek F.

;

Soh P.J.

;

Romli A.

;

Abd Rani K.

;

Isa C.M.N.C.

;

Fuad F.A.A.

This study presents the measurement of dielectric properties of textile substrate in which is used in fabricating the textile antenna. The measurement setup of felt's dielectric properties is shown in this study. The results were compared to the previous work where the dielectric properties of felt was found to be consistent with the one reported in the literature. This research provides dielectric properties value of felt textile which will be used widely for all-textile based antennas.

Publication

ESD improvement in P-i-N diode through introducing a lighter and deeper anode junction

( 2017-01-01)

See J.

;

Md Arshad M.

;

Fathil M.

Continuous and aggressive miniaturization in the electronic gadget size poses a challenge in solving Electrostatic Discharge (ESD) reliability performance. For diode devices, the shrinkage of the size leads to severe electrical field crowding effect which can cause a total device failure under high ESD surge. Therefore, in this paper, we present a better ESD performance characteristic which can be achieved by optimizing the profile of the P+ anode junction of P-i-N diode. The characteristics profile can be altered by lowering the dopant concentration and increasing the depth of the P-i-N diode junction. In this work, comprehensive device simulations, followed by simulation result validation at the wafer level were performed. The ESD surge test was performed and results showed that the changes of the P+ anode junction profile on the P-i-N power switching diode can achieve the sustainability of 1 kV ESD surge in the Human Body Model (HBM) and more than 400 V ESD surge in the Machine Model (MM).

Publication

Impact of secondary phases content on the mechanical properties of cordierite

( 2017-01-01)

Eing Kuan Kok

;

Banjuraizah Johar

;

Ho Li Ngee

;

Zabar Yahidah

The Cordierite ceramic body had been synthesized through conventional techniques solid state reaction by using non-stoichiometric composition (2.5 MgO. 1.8 Al2O3. 5 SiO2). The sintering temperature study was carried out by heat treated the samples at several degree of sintering temperature (1250 °C, 1275 °C, 1300 °C, 1325 °C, 1350 °C and 1375 °C). The qualitative and quantitative of crystalline phase analysis was accomplished by using X-ray Diffraction (XRD) technique and Rietveld structural refinement. The Scanning electron microscopy (SEM) was employed for morphology analysis. The mechanical properties of samples were determined by Vicker's Hardness test. Rietveld quantitative phase analysis results show that α phase Cordierite constitutes up to 96.4 wt% when the samples was sintered for 2 hours at sintering temperature of 1375 °C and obtained densified and orderly crystal structure arrangement in SEM micrograph except the mechanical strength. The sample obtained the uppermost α phase Cordierite content gained the lowest hardness values (4.0±0.8GPa). Conversely, the sample contains 90 wt% α-cordierite and 1.4 wt% magnesium titatnate achieve highest hardness which is about 4.9±0.79GPa.

Publication

Hybrid OCDMA/WDM system using Spectral Direct Detection technique for Gigabit Passive Optical Network application

( 2017-01-01)

S.M. Monirul Islam

;

Nasim Ahmed

;

Sharafat Ali

;

Rahman M.

;

Syed Alwee Aljunid Syed Junid

;

R Badlishah Ahmad

This study a hybrid Optical Code Division Multiple Access (OCDMA) over Wavelength Division Multiplexing (WDM) network is proposed to supporting large numbers of subscribers for Gigabit Passive Optical Network (GPON). Gigabit Passive Optical Network (GPON) is a developing innovation for satisfying high transfer speed interest of clients with long separation scope. In this study, the Modified Double Weight (MDW) code is used as signature address to designing the system regarding this code can accommodate huge number of simultaneously active users. The simulation model of GPON systems is derived by Spectral Direct Detection (SDD) technique which has been developed for the analysis of feasibility and implementation issues of the application. The aim was to analyse the impact of the most important parameters of the components that are needed for new network elements. On the basis of the results achieved (e.g., =10-10) the optimal of the GPON system for 20 km fibre length. Hence, this system can be considered as a promising solution for gigabit passive optical network application.

Publication

The effect of liquid natural rubber as toughening agent in epoxy/LNR/CB composite

( 2017-01-01)

Fauzi F.S.

;

Teh P.L.

;

Du N.U.L.

;

Yeoh C.K.

Liquid natural rubber (LNR) was used as the toughening agent to overcome the brittleness of epoxy thermoset matrix. The LNR were prepared by using depolymerization method. The experiment was consist of two parts of study, first, epoxy filled with carbon black to get the optimun 15 vol.% content of carbon black (CB). Second, epoxy with various amount LNR and at 15 vol.% CB content. This can be seen from the result of flexural properties testing, fracture toughness testing and SEM morphology. The best properties of LNR as toughening as 4 phr because it gave optimun performance compared to others LNR content.

Publication

Experimental design of the effects of RF shielded hat on Electroenc Ephalo Gram (EEG) of cameraman

( 2017-01-01)

Hisham N.

;

Rahim H.

;

Malek F.

;

Jusoh M.

;

Fuad F.

;

Romli A.

In this study, the effects of exposure to Radio Frequency Electromagnetic Fields (RF-EMF) on cameraman will be investigated using Electro Encephalo Gram (EEG). There are two hypothesis will be tested which is firstly include the exposure of cameraman to the radio frequency that will affect their brain activity. Second, hypothesis involve the cameraman wearing a RF shielded hat can reduce the effect of exposure to RF-EMF. The 20 healthy cameramen will be involved in this experiment. Well-being and physiological measures of body temperature, blood pressure and heart rate will be obtained. The 2 types of exposure conditions will be conducted (Sham (no exposure) and wireless video-camera exposures). Each exposure will be lasted for 20 min session.

Publication

Mechanical properties of copper ferrite CuFe2O4-polymer composite fabricated using 3D printer

( 2017-01-01)

Lee C.H.

;

Yeoh C.K.

;

Hamzah K.A.

;

Teh P.L.

The effect of speed of powder dispenser on the mechanical properties of ABS-CuFe2O4 composites was studied. The samples in the experiment were printed by a 3D printer which produces three-dimensional objects from the digital file which are built up layer by layer. The amount of filler content added into each sample was controlled by the speed of powder dispenser which is off, low, medium, and high. The properties of pure ABS and composite ABS CuFe2O4 samples were investigated based on the distribution of fillers. Weight percentage (wt%) of filler added into each sample was determined by using thermogravimetric analysis (TGA). Tensile test and Vickers micro hardness were carried out to determine the effect of filler content on mechanical properties. Addition of filler content in ABS matrix slightly decreases the strength of composite from 17.1 MPa to 14.64 MPa.

Publication

On the existence and uniqueness of solutions of fractional order partial integro-differential equations

( 2017-01-01)

Hussain A.K.

;

Fadhel F.S.

;

Rusli N.

;

Yahya Z.R.

The main objective of this paper is to investigate and prove the existence and uniqueness theorems of the solution of nonlinear partial integro-differential equations of fractional order. The theorems of two types for the nonlinear fractional order partial integro-differential equations such as one- and two-dimensional are proved by applying the fixed point theorem of Banach space couple with contraction mapping principle, in which the sufficient conditions are presented in order to ensure the existence and uniqueness of a unique fixed point related to the integro-differential equation in operator form.

Publication

Implementation of on-chip optical interconnect in high speed digital circuit: Two-stage CMOS buffer

( 2017-01-01)

Sallah S.S.B.M.

;

Ali S.H.M.

;

Menon P.S.

;

Juhari N.

;

Islam M.S.

Background: Silicon based photonics has created strong interested in recent years, mainly in optical waveguide interconnects for microelectronic circuits. Materials and Methods: This study reports on the implementation of an Optical Interconnect (OI) waveguide in a digital electronic circuit, a two-stage CMOS buffer. To compare the performance between several waveguide materials with copper interconnect, the optical waveguide was designed and evaluated in OptiBPM to be in a single mode condition. Then, the OI link was simulated in OptiSPICE and their ability as an interconnection was tested in a two-stage CMOS buffer. A propagation delay performance for the whole circuit and for the interconnection only was measured using different material of interconnect. Results: The results showed that the OI minimized the propagation delay in the two-stage CMOS buffer circuit, as well as increased the speed of the integrated circuit. Conclusion: The proposed SOI-based optical waveguide in OI link are able to replace copper based electrical interconnection in electronic circuit technology.

Publication

Study of eddy current density distribution in a contactless breast cancer detection mechanism using magnetic induction spectroscopy

( 2017-01-01)

Gowry Balasena

;

Shahriman Abu Bakar

;

Zulkarnay Zakaria

;

Ryojun Ikeura

;

Zuradzman Mohamad Razlan

;

Hazry Desa

;

Wan Khairunizam Wan Ahmad

;

Cheng Ee Meng

;

Mohd Afendi Rojan

Breast cancer is a throbbing disease that no longer needs an introduction. This is especially true among women due to their unique breast structure that naturally has more breast tissues compared to that of man’s. It is been forecasted that in 2015, a minimum of 60290 new cases of breast cancer will be reported. The goal of this study is to analytically evaluate the changes in the induced Eddy current densities as a function of di-electrical properties of the breast tissue with respect to tumor positioning as well as its size. This is achieved by running numerical simulations on the proposed mechanism of magnetic induction to detect tumors among healthy breast tissue via a 2D breast model configuration. The analytical results presented in this article, proved that the multi frequency magnetic induction principle is viable in detecting the breast lesions as small as 0.2 cm non-invasively through the distributions of the induced Eddy current density. While important pattern of the induced current were reflected when the tumors are located at the far ends of the breast diameter. The minimum results computational time with the proposed system is 10 s.

Publication

Predominance performance of Sequential Algorithm (SeQ) code in an optical CDMA networks

( 2017-01-01)

Fazlina C.A.S.

;

Rashidi C.B.M.

;

Rahman A.K.

;

Ljunid S.A.A.

;

Anuar M.S.

This study present a new Sequential Algorithm (SeQ) code structure for Optical Code Division Multiple Access (OCDMA) system with flexible cross-correlation has been proposed. In contrary to the existing codes, this SeQ code provides much better performance in term of Bit Error Rate (BER) and Signal Noise Ratio (SNR) for any number of active users. This newly proposed code can adapt to any variable numbers of users by using tridiagonal code matrix. The result obtained from comparison with existing code, DCS, MDW and Hadamard. Thus, at the typical error rate of optical communication system BER = 10-9 this study illustrate that SeQ code can accommodate 190 numbers of simultaneous users compared with DCS (W = 4), MDW (W = 4) and Hadamard (W = 4). This SeQ code capable to enhance performance BER about 46, 27, 100% in comparison with DCS (W = 4), MDW (W = 4) and Hadamard (W = 4) codes. In addition, SeQ code has revealed that this code can improve OCDMA system due SeQ code has highest SNR of 200 numbers of simultaneous users compared with DCS (W = 4) and MDW (W = 4). Thus, the results obtained in this study as an evidence that SeQ code was truly performed better than existing codes and applicable to enhance OCDMA system network for future generation usage.

Publication

Bandwidth enhancement technique with low group delay variation CMOS power amplifier for UWB system

( 2017-01-01)

Rohana Sapawi

;

Siti Kudnie Sahari

;

Dayang Nur Salmi Dharmiza Awang Salleh

;

Dayang Azra Awang Mat

;

Sohiful Anuar Zainol Murad

This paper introduced a bandwidth enhancement technique for ultra-wideband (UWB) transmitter design with low group delay variation for CMOS power amplifier (PA). Three stages of cascade common source topology are implemented to provide high gain with good gain flatness. Shunt peaking inductor is introduced at every stage of the introduced PA to improve the bandwidth and to achieve low group delay variation simultaneously. A resistive shunt feedback method is implemented at the first stage to acquire good input matching. The first and second stages attain gain at lower corner and upper-end frequency respectively, whilst the third stage smoothed the gain flatness curve. In addition, the theoretical analysis of group delay is investigated to determine the important design factor for low group delay variation in 3.1 to 10.6 GHz CMOS PA for UWB transmitters. The outcome of the research shows that a gain about 11.48 ± 0.6 dB at average, S11 less than -10 dB, and S22 less than -14 dB is achieved. Moreover, excellent group delay variation is acquired throughout the entire band, measuring about ±85.8 ps.

Publication

Analytical method using virtual PM blocks to represent magnet segmentations in surface-mounted PM synchronous machines

( 2017-01-01)

Tiang T.

;

Ishak D.

;

Lim C.

;

Rezal M.

This paper describes an analytical subdomain model to predict the magnetic field distributions in the semi-closed surface-mounted permanent magnet synchronous machines (PMSMs) due to magnet segmentations with radial magnetization (RM). The magnet segments per pole can be virtually represented by finite number of permanent magnet (PM) blocks and Fourier decompositions. The model can also determine the optimum magnet pole-arcs for each segment and the optimum airgap spacing between the segments. The analytical model is then applied to evaluate the performance of a three-phase, 12-slot/8-pole, surface-mounted PMSM having two segmented magnets per pole with RM. With design objective for minimum cogging torque and minimum total harmonic distortion in phase back-emf waveforms, we obtain that the optimum settings are 147.6° elect. for magnet segment pole-arc and 11.2° elect. for airgap spacing between the magnet segments. These analytical results are further compared and validated by 2-D finite element analysis (FEA). Additionally, we also compare the results with those from the optimum magnet pole-arc of one magnet segment per pole machine. It is observed that the cogging torque and total harmonic distortion THDν of the phase back-EMF are significantly reduced by 89% and 25%, respectively, with constraint and assumption that both machines utilize similar total magnet volume.

Publication

Single feed circularly polarized antenna with switchable beam ability

( 2017-01-01)

Jusoh M.

;

Sabapathy T.

;

Rahim H.

;

Shakhirul M.

;

Rahman A.

;

Yasin M.

;

Mat M.

A single feed circularly polarized antenna with the ability to steer the beam has been presented. The presented antenna has successfully achieved circular polarization by ensuring the axial ratio (AR) factor value of less than 3 for 2.4 GHz application. Moreover, by integrating four ideal p-i-n diode switches, the antenna‘s radiation pattern can be directed to the desired direction while suppressing the antenna gain at the unwanted angle without influencing the antenna‘s impedance bandwidth. This antenna is managed to steer the beam with certain p-i-n diode configuration at nine distinguished angle directions. Such microstrip antenna with a simple circular shape is designed on the Taconic substrate with the compact size of 100 mm square. A fully functional antenna design has been developed and tested using CST Microwave Studio. The proposed antenna could be useful for advanced and smart radio application such as 5G and cognitive radio (CR).

Publication

A direct detection of human papillomavirus 16 genomic DNA using gold nanoprobes

( 2017-01-01)

Azizah N.

;

Hashim U.

;

Gopinath S.C.B.

;

Nadzirah S.

Nanoparticles have been investigated as flagging tests for the sensitive DNA recognition that can be utilized as a part of field applications to defeat restrictions. Gold nanoparticles (AuNPs) have been widely utilized due to its optical property and capacity to get functionalized with a mixed bag of biomolecules. This study exhibits the utilization of AuNPs functionalized with single-stranded oligonucleotide (AuNP-oligo test) for fast the identification of Human Papillomavirus (HPV). This test is displayed on interdigitated electrode sensor and supported by colorimetric assay. DNA conjugated AuNP has optical property that can be controlled for the applications in diagnostics. With its identification abilities, this methodology incorporates minimal effort, strong reagents and basic identification of HPV.

Publication

A review of droop control techniques for microgrid

( 2017-01-01)

Tayab U.B.

;

Roslan M.A.B.

;

Hwai L.J.

;

Kashif M.

Coordination of different distributed generation (DG) units is essential to meet the increasing demand for electricity. Many control strategies, such as droop control, master-slave control, and average current-sharing control, have been extensively implemented worldwide to operate parallel-connected inverters for load sharing in DG network. Among these methods, the droop control technique has been widely accepted in the scientific community because of the absence of critical communication links among parallel-connected inverters to coordinate the DG units within a microgrid. Thus, this study highlights the state-of-the-art review of droop control techniques applied currently to coordinate the DG units within a microgrid.

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