Displaying publications 21 - 40 of 811 in total

  1. Sharmila Karim, Zurni Omar, Haslinda Ibrahim, Khairil Iskandar Othman, Mohamed Suleiman
    Linear array of permutations is hard to be factorised. However, by using a starter set, the process of listing the permutations becomes easy. Once the starter sets are obtained, the circular and reverse of circular operations are easily employed to produce distinct permutations from each starter set. However, a problem arises when the equivalence starter sets generate similar permutations and, therefore, willneed to be discarded. In this paper, a new recursive strategy is proposed to generate starter sets that will not incur equivalence by circular operation. Computational advantages are presented that compare the results obtained by the new algorithm with those obtained using two other existing methods. The result indicates that the new algorithm is faster than the other two in time execution.
  2. Norasma, C.Y.N., Shariff, A.R.M., Jahanshiri, E., Amin, M.S.M., Khairunniza-Bejo, S., Mahmud, A.R.
    Precision farming offers numerous benefits and advantages to the farming community for farm productivity improvement. Previous research has led to the development of the offline-based recision Farmer©. Our current research extends further the previous work by developing a Web Paddy GIS©. The need for this arises due to limitations of Precision Farmer© such as portability, offline system accessibility and affordability by the end users, who include semi-literate farmers. This new system has been developed to function on Windows and Linux platforms. A user satisfaction assessment was conducted on website acceptability, and performance testing was made. This study demonstrates that Web Paddy GIS© can successfully run on both platforms. However, the Linux platform has proven to be superior to Windows, based on factors such as CPU usage, speed and user satisfaction. This paper presents a novel management tool of Web-based precision farming for the semi-literate paddy farming community of a developing country. The development of the Web Paddy GIS© is very useful for paddy farmers, farm managers, decision makers and researchers.
  3. Wan Ishak, W.I., Hudzari, R.M., Tan, M.Y.
    Vapour pressure deficit (VPD) analysis introduces an approach to develop a better basis for the control of the environment of lowland greenhouses in Malaysia. The study of vapour pressure deficit (VPD) is to show air moisture conditions for plant production while taking into account different temperature levels. The purpose of this project is to develop a real-time automatic temperature and relative humidity control system in the lowland tropical greenhouse using a PIC16f876A microcontroller. The controller will then be used to monitor the temperature, relative humidity and VPD in the planting of Chili Kulai (Titisan 15). The fertigation system was introduced to the greenhouse to fertilize and irrigate the plant as well as to provide moisture to the environment. A swamp cooler was used to bring down the temperature and increase moisture content in the greenhouse. Ventilators were installed to remove the heat in the greenhouse. The study was carried out in an experimental greenhouse located at the Institute of Advanced Technology, Universiti Putra Malaysia (UPM).
  4. Lian, Oh Chai, Wee, Lee Siong, Mohd Asha’ari Masrom, Hua, Goh Ching
    Recently, there has been great interest on the applicability of Recycled Concrete Aggregate (RCA) as a new ecological construction material that can be sustainable in a gradually expanding construction industry. This paper reports the structural performance particularly on shear behaviour of high strength reinforced recycled concrete beams. Compressive cube strength of the tested beams ranged from 65-74 MPa at the age of 28-days. The experimental program compared conventional concrete mix with concrete mix having substitution of 25% recycled concrete aggregates of grade 25-30 MPa. In this study, three 150 mm x 200 mm x 1200 mm simply supported rectangular concrete beams in each mix were tested under a four-point bending static load with various shear span to effective depth ratios (a/d = 1.0, 1.5, 2.0). Subsequently, the shear behavior of the beams was investigated through studies of load-deflection responses, effect of a/d ratios and crack patterns. The test results reported that the substitution of 25% recycled concrete coarse aggregates barely affects the shear capacity of the high strength reinforced concrete beams with a/d of 1.5 onwards. Finally, experimental results were compared using existing design codes by ACI 318, Eurocode-2 and AS3600 which lie on the safe side.
  5. Muntohar, A.S., Rahman, M.E., Hashim, R., Islam, M.S.
    The importance of numerical analysis in investigation of piled embankment over soft soil has been developed since 1990. Several investigators have extended the numerical analysis to model ground improvement using soil-column to support embankment or structures. This paper presents a numerical analysis of the Pulverized Fuel Ash (PFA) column-treated peat and compared with field static-loading test results. Back analysis was performed to determine the material parameters and soil stiffness surrounding soil & soil-column. Two geometrical models were used in this analysis: (a) block (Model A), and (b) column group (Model B). This situation was analyzed using commercially available finite element package PLAXIS 2D ver. 8.2. It is found that both models are reliable to simulate the field static-loading test for column-treated peat. Model B shows a higher stability to failure if compared to Model A.
  6. Ali, A.H.M., Sobri, S., Salmiaton, A., Faizah, M.Y.
    The process of etching is the most crucial part of the work of manufacturing printed circuit boards (PCB). In the etching process by nitric acid, a spent etching waste solution of composition 250 g/L HNO3, 30-40 g/L Cu, 30-40 g/L Sn, 30-40 g/L Pb and 20-25 g/L Fe is produced. High metal concentrations in the spent etching waste solution make it a viable candidate for the recovery of metals. Recovery of metals from spent etching waste solution is a significant concern as the recent growth in production of printed circuit boards has generated a drastic increase of spent etching waste solution each year. This study concerns itself with the recovery of metals from spent etching waste. In this study a dilution was made in order to increase the pH of the solution as spent etching waste solution has high acidity, and the electrowinning method was performed to recover metals from the spent etching waste solution. Glassy carbon and platinum were used as cathode and anode in order to investigate the electrodeposition of metals and cyclic voltammetry investigation suggests that the deposition of metals on glassy carbon electrodes occurs at four different overpotentials mainly at -0.15 V, -0.35 V, -0.45 V and -0.75 V. Microscopy observation demonstrates that there is a deposition of metals by applying the potentials in a set of current-time transient study for a duration of 60 seconds and the metals recovered formed as aggregates.
  7. Khairul Nizam Tahar, Anuar Ahmad
    The objective of this study was to investigate the capabilities of low-cost digital cameras in volume determination. Low-cost digital cameras are capable of many applications including aerial photogrammetry and close-range photogrammetry. Low-cost digital cameras have the potential to be used in landslide monitoring and mapping. In this study, a low-cost digital camera was used as a tool to acquire digital images of a model of a simulated landslide. The model was constructed using cement and sand with the dimensions of 3m in length and 1m width. Digital images of the simulated model were acquired using the technique of aerial photogrammetry and were subsequently processed using digital photogrammetric software. A portion of the simulated model was excavated to simulate a landslide and volume determination was carried out for the excavated sand. The results showed that low-cost digital cameras can be used in photogrammetric application including volume determination.
  8. Syahrizal Salleh, Zulkifli Abd Majid
    An AC to DC voltage rectifier and its respective regulator were designed and integrated on a 0.25μm CMOS process. Its input impedance was measured along with the regulated DC output. Input impedance of a series of rectangular coil microstrip antenna on FR4 PCB with outer dimension of 78mm x 41mm was measured. The positive reactance of the antenna was matched at resonance with negative reactance of the integrated rectifier and regulator with addition of external capacitor. Relationship between incidental electromagnetic field in A/m at the coil microstrip antenna all the way to the rectified DC voltage at the output of the regulator is presented. In the context of wireless power transfer, this work focuses on the remote unit that absorbs electromagnetic field generated by another system and converts the energy into DC supply voltage for remote device
  9. Nik Azmi Nik Mahmood, Mohd Nazlee Faisal Md Ghazali, Kamarul’Asri Ibrahim, Nur Muhammad ElQarni Md Norodin
    The aim of this project is to produce electricity from citronella biomass using isolated microbes from wastewater as biocatalyst in a dual chamber microbial fuel cell (MFC). MFC is one such system that not only reduced biomass, which contains mostly waste products but can also liberate electricity from them. MFC system is well-established and using lignocellulosic biomass as fuel is one step to future energy generation. Trials of MFC experiments have been conducted but using citronella bagasse (CB) as fuel source. Furthermore, pre-treatment of the biomass was done using NaOH pre-treament and effluent treatment wastewater from a palm edible oil company as a source for microorganism. The end results indicate that bioelectricity production from CB is possible though very low yield in the present MFC.
  10. Hussain H. Al-Kayiem, Iylia Elena Abdul Jamil
    In the moving layer of particles with variable concentration, the shear estimation is not directly predictable and there is no existing clear mathematical or empirical formula to achieve this objective. This paper presents a developed approach to estimate the shear forces in a flow having suspended and moving layers of solid particles in liquid flow. The two-layer approach was taken whereby the flow consisting of one upper suspended layer of particles in the liquid, and the bottom layer was the moving bed of particles. In the present work, the method of finding the force acting on the pipe wall by the particles in the layer, termed as the ‘dry force’, was presented using a “pseudo hydrostatic pressure” method. To attain the equation for the dry force, a mathematical approach is taken with the assumptions that the flow is horizontal, two-phase pipe flow (solid in Newtonian liquid), incompressible and it is at steady-state. The analysis was conducted considering various particles densities, various concentrations in the suspended layer and different thicknesses of the moving bed. Changing the concentration in the suspended layer from 0.00001 up to 0.001 didn’t showed significant changes in the dry force evaluation. The dry friction force is increasing with increasing moving bed thickness. The developed mathematical model can be
    applicable in solving for the shear force in horizontal solid liquid two-phase flows.
  11. Ravi Kumar, P., Alex Goh, K.L., Ashutosh, K.S.
    Link analysis algorithms for Web search engines determine the importance and relevance of Web pages. Among the link analysis algorithms, PageRank is the state of the art ranking mechanism that is used in Google search engine today. The PageRank algorithm is modeled as the behavior of a randomized Web surfer; this model can be seen as Markov chain to predict the behavior of a system that travels from one state to another state considering only the current condition. However, this model has the dangling node or hanging node problem because these nodes cannot be presented in a Markov chain model. This paper focuses on the application of Markov chain on PageRank algorithm and discussed a few methods to handle the dangling node problem. The Experiment is done running on WEBSPAM-UK2007 to show the rank results of the dangling nodes.
  12. Alfian Abdul Halin, Rajeswari, Mandava
    Detecting semantic events in sports video is crucial for video indexing and retrieval. Most existing works have exclusively relied on video content features, namely, directly available and extractable data from the visual and/or aural channels. Sole reliance on such data however, can be problematic due to the high-level semantic nature of video and the difficulty to properly align detected events with their exact time of occurrences. This paper proposes a framework for soccer goal event detection through collaborative analysis of multimodal features. Unlike previous approaches, the visual and aural contents are not directly scrutinized. Instead, an external textual source (i.e., minute-by-minute reports from sports websites) is used to initially localize the event search space. This step is vital as the event search space can significantly be reduced. This also makes further visual and aural analysis more efficient since excessive and unnecessary non-eventful segments are discarded, culminating in the accurate identification of the actual goal event segment. Experiments conducted on thirteen soccer matches are very promising with high accuracy rates being reported.
  13. Yow, K.S., Sapar, S.H., Atan, K.A.
    This paper investigates and determines the solutions for the Diophantine equation x2 + 4.7b = y2r, where
    x, y, b are all positive intergers and r > 1. By substituting the values of r and b respectively, generators of
    x and yr can be determined and classified into different categories. Then, by using geometric progression
    method, a general formula for each category can be obtained. The necessary conditions to obtain the
    integral solutions of x and y are also investigated.
  14. Siti Nurul Ain Md. Jamil, Rusil Daik, Ishak Ahmad
    Redox polymerization of acrylonitrile (AN) with ethyl acrylate (EA) and fumaronitrile (FN), as comonomer and termonomer respectively, were carried out using sodium bisulfite (SBS) and potassium persulphate (KPS) as initiators at 40°C. The actual composition of monomers in copolymers and terpolymers has been characterized by gas chromatography (GC). The effects of EA and FN on the glass transition temperature (Tg) and stabilization temperature have been studied by Differential Scanning Calorimetry (DSC). The degradation behaviour and char yield were obtained by thermogravimetric analysis. Meanwhile, incorporation of 10 mol% of EA in homoPAN system was found to greatly reduce Tg to 66°C as compared to that of the homoPAN (Tg=105°C). The initial cyclization temperature (Ti) was found to be higher (264°C) in comparison to that of homoPAN (246°C). In addition, the incorporation of EA was also shown to reduce the char yield of copolymer to 40%. When FN was incorporated as termonomer, the char yield of poly(AN/EA/ FN) 90/4/6 increased up to 44% after the heat treatment with the lowest Ti (241°C).
  15. Kiing, Sie Cheong, Balasubramaniam, Jaya-Raj, Yiu, Pang Hung, Wong, Sie Chuong, Amartalingam, Rajan
    Polyethylene is a widely used packaging material, but its non-biodegradable nature can lead to waste
    disposal problems. This increases the concern in research and development of biodegradable plastics from natural resource as alternatives to petroleum-derived plastics. In this study, biodegradable plastic composites were prepared by blending thermoplastic starch with natural rubber in the present of glycerol as plasticizer. Local sago starch was cast with 0.5 to 10% of natural rubber to prepare the bioplastic. The products were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), water absorption test, biodegradable test, hydrolysis test, and mechanical analysis. Meanwhile, composite with natural rubber latex was increased from 0.5 to 10% showing that the melting temperature is in the range of 120 to 150˚C, but with no significant difference. The water absorption characteristics, biodegradability, and tensile strength decreased by 11.21%, 30.18%, and 20.733 MPa, respectively. However, the elongation at break was increased from 26.67 to 503.3%. The findings of this study showed that sago starch has a great potential in bioplastic production with good miscibility and compatibility.
  16. Abdalla A. Ab. Rashdi, Mohd Sapuan Salit, Khalina Abdan, Megat Mohamad Hamdan Megat
    Fibre reinforced composites have gained use in a variety of applications. The performances of these composites may suffer when the material is exposed to adverse environments for a long period of time. Kenaf fibre reinforced unsaturated polyester composites were subjected to water immersion tests in order to study the effects of water absorption on the mechanical properties. Composites specimens containing (10%, 20%, and 30%) weight percentages of fibre were prepared. Water absorption tests were conducted by immersing these specimens in a distilled water bath at 25oC for four months. The tensile properties of the specimens immersed in water were evaluated and compared with the dry composite specimens. A decrease in the tensile properties of the composites was demonstrated, indicating a great loss in the mechanical properties of the water-saturated samples compared to the dry samples. The percentage of moisture uptake was also increased as the percentage of the fibre weight increased due to the high cellulose content. The water absorption pattern of these composites was found to follow the Fickian behaviour.
  17. Chieh, C.W., Asmawi Sanuddin, Reza Afshar, Aidy Ali
    The paper presents a simulation work conducted on the elastomer subjected to cyclic loads. A 3D finite element model of elastomer specimen, in accordance to ASTM D412, was developed using CATIA and ANSYS commercial finite element (FEM) packages. Fatigue life predicted from the simulation was compared with well-documented published data and it showed an acceptable agreement. Meanwhile, the simulated strain-life results are slightly lower than the experimental data. Several factors which potentially influenced the variations of the results were noted. Finally, some recommendations are offered at the end of this study to further improve the simulation
  18. Intan S. Ismail, NorAkmar Ismail, Nordin Lajis
    The preliminary ichthyotoxic test on all parts of Syzygium malaccense (Myrtaceae) revealed that the leaves fraction was the most ichthyotoxic against tilapia-fish (Tilapia oreochromis). Three compounds, namely ursolic acid (1), β-sitosterol (2) and sitost-4-en-3-one (3), were isolated and their structures were elucidated with the aid of spectroscopic data and comparison with previously reported investigations. However none of these compounds gave any significant ichthyotoxicity. The volatile constituents of the leaves and fruit were determined by Gas Chromatography-Mass Spectrometer (GC-MS), with 180 and 203 compounds being identified in the aroma concentrates, respectively.
  19. Jaafar, M.S., Thanoon, Waleed A., Mohammed, T.A., Huda, A.M., Noorzaei, J.
    An attempt was made in this investigation to trace the dynamic response of roller compacted concrete dam, which is subjected to horizontal ground motion by considering the interactions between flexible foundations, reservoir water, and bottom reservoir sediments. Two-dimensional finiteinfinite element was used for the non-linear elasto-plastic dynamic analysis. In this analysis, special emphasis was given to the non-linear behaviour of discontinuities along RCC dam-bedding rock foundation which was modelled by thin layer interface. Analysis was first carried out under static loading (self-weight and hydrostatic pressure), and this this was followed by seismic analysis, with hydrodynamic pressure effect in a dam-reservoir system. Based on the numerical dynamic results, it is concluded that the bottom reservoir sediment has significant effect on the seismic response of the RCC gravity dam. Moreover, there is a redistribution of the stresses at thin layer interface with significant stresses reduction, which is resulted from the release of energy through different modes of deformation in this region.
  20. Mohd Ashraf Ahmad, Zaharuddin Mohamed
    This paper presents investigations into the development of control schemes for end-point vibration
    suppression and input tracking of a flexible manipulator. A constrained planar single-link flexible manipulator is considered and the dynamic model of the system is derived using the assumed mode method. To study the effectiveness of the controllers, a Linear Quadratic Regulator (LQR) was initially developed for control of rigid body motion. This is then extended to incorporate a noncollocated PID controller and a feedforward controller based on input shaping techniques to control vibration (flexible motion) of the system. For feedforward controller, positive and modified specified negative amplitude (SNA) input shapers are proposed and designed based on the properties of the system. Results from the simulation of the manipulator responses with the controllers are presented in time and frequency domains. The performances of the control schemes are assessed in terms of level of vibration reduction, input tracking capability and time response specifications. Finally, a comparative assessment of the control techniques is presented and discussed.
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