Displaying publications 1 - 20 of 811 in total

  1. Muhammad Hanihazaim Abd Halim, Mahanijah Md Kamal
    In this work, two types of controller were designed for the nonlinear air blower system PT326 used at
    the Instrumentation Laboratory Faculty Electrical Engineering, UiTM, Shah Alam. This work began with
    collection of data from the experimental work. Once the S-shape of the system response was obtained,
    the procedure of getting the process dead time, τD and time constant τC was applied to the S-shape form.
    By determining these two values, the optimum values of PI and PID controllers can be calculated. From
    the acquired data, the simulation model was developed in MATLAB/Simulink R2013a software using
    the transfer function obtained from the open-loop control system. The modelling system is based on
    the transfer function of open-loop air blower system PT326 before the design state of finding a suitable
    controller can be suggested. The controller design of PI and PID was obtained using the first method
    Ziegler-Nichols tuning rules. The result from the simulation shows that the Ziegler-Nichols first tuning
    rules can be applied in designing the PI and PID controller based on S-shape response obtained in
    open-loop test.
  2. Suhaidi Shafie, Halah Saadoon Shihab, Fauzan Ahmad, Ramli, A.R.
    Discrete Wavelet Transform (DWT)-based image compression techniques have been utilized in most of the earth observation (EO) satellites launched during the last few decades, since they have proved to be more efficient than other methods used previously with remote sensing multispectral imaging payloads. The efficiency of these techniques is mainly due to their high compression ratio that can be achieved while maintaining the quality of the compressed image. Also, they are considered multi-resolution compression techniques. However, these techniques are considered computationally demanding, due to their complex and sophisticated hardware. Due to the limited computational resources available on-board small satellites, they are considered one of the important criteria when choosing the satellite image compression method, along with the compression ratio and quality of the reconstructed image. Hence, an alternative DWT-based method was proposed, developed and implemented in this work with the aim of reducing the computational resources on-board a small satellite, replacing the regular DWT thresholding and quantization processes that are usually used to achieve lossy compression, with the zero-padding technique. This method will also help to control the change in the compression ratio and quality of the reconstructed image according to the end-user’s scientific needs of the satellite image. The
    results of this work indicated, objectively and subjectively, that a decrease in the computational resources required on-board satellites was achieved by decreasing the processing time needed to complete the compression, without a significant difference in quality of the image reconstructed at the ground station.
  3. Haque, A.U., Asrar, W., Sulaeman, E., Ali, J.S.M., Omar, A.A.
    All buoyant and hybrid buoyant aerial vehicles have directional stability issues at low speed. Electric
    trimmers are one of the potential solutions for controlling the yaw motion of such vehicles in which
    partial lift is obtained from the wings. However, available propeller disk area of such trimmers is limited
    due to small surface area of the vertical tail. In the present work, maximum input power required by thin
    electric propellers with different pitch values are compared to obtain an optimised value of pitch for
    propeller selection. Analytical as well as computational techniques are employed to evaluate the moment
    generated by tangential thrust produced by a ducted propeller. Motocalc® software under predicts the
    thrust value when compared with the computational results under the same flow conditions. The estimated
    yaw force produced by the propeller is quite significant and it can also be used for creating differential
    thrust using twin electric motors.
  4. Ee, G.C.L., Jong, V.Y.M., Sukari, M.A., Rahmani, M., Kua, A.S.M.
    The roots of Calophyllum inophyllum (Guttiferae), furnished six xanthones which are brasilixanthone (1), 1,3,5-trihydroxy-2- methoxy xanthone (2), caloxanthone A (3), pyranojacareubin (4), caloxanthone B (5) and tovopyrifolin (6), Structural elucidations of these compounds, were achieved through 1D and 2D NMR andMS techniques. In this paper, the isolation and structural elucidation data for these xanthones are reported.
  5. Shirazi, A.H.S., Muda, M.K.H., Thirumurthy, M.J., Mustapha, F.
    This paper presents an improved version of a wireless device embedded with a smart PZT sensor to
    detect flaws and structural defects on selected investigated structure. Smart PZT sensors were used as an
    actuator and sensor, coupled with two XBee’s and one signal generator IC chip. Programme execution on
    transmitting and receiving the ultrasonic guided wave via the PZT sensor had been written in MATLAB.
    The developed source code is basically to receive serial data from one Xbee to another remote Xbee attached
    to the investigated structural system. The refined waveform response is utilised for prognosis of the true
    structural status. The 4-mm simulated holed into one of the aluminium structural plate is benchmarked
    with its pristine condition in validating the effectiveness of the developed SHM wireless module. Results
    showed that the wave is more even in non-defected area and disrupted in affected area. Ultrasonic waves
    increase continuously for non-destructive evaluation and structural health monitoring in various structural
    applications because the guided wave can propagate long distances and reach difficult-to-access regions;
    for inspecting porous and some non-porous materials ultrasonic waves attenuate fast and are very useful.
    Recent advances in ultrasonic wave application model and results are discussed in this paper.
  6. Zulkifli, C.Z., Noor, N.N.
    This paper presents the technology of Active Radio Frequency Identification (RFID) and Wireless Mesh
    Sensor Network (WMSN) that will be used in agriculture. In this paper, ZigBee technology platform is
    applied in 2.45 GHz and active RFID to sustain the WSN by developing a fully automated IoT solution
    in agriculture for irrigation system. The system includes a plurality of sensor nodes installed in a crop
    field sending an ID, which are embedded sensor and WSN that work on ZigBee 2.4 GHz platform. The
    ID was sent to act as a signal of soil in dry condition of a specific area to a reader at base station. The
    pump stations will use information from base station to sprinkling water in the specific area of the dry
    state automatically. The automatic control system is very practical in agriculture but most of it is based
    on schedule and timer regardless of soil condition and temperature. Therefore, wireless automated
    irrigation system for efficient water use and production is proposed.
  7. Hanipah, M.H., Abdullah, A.H., Che Sidek, N.A., Yunus, R., Nagapan, S., Yassin, M.N., et al.
    Rapid urbanisation and industrialisation have had an adverse and deep impact on the environment contributing to global warming and climate change. These thermal environmental problems can be even more challenging to people living in regions with warm and humid climatic conditions throughout the year, such as Malaysia. This paper analyses wind characteristics and outdoor thermal comfort index at the hottest temperatures based on data recorded hourly between 2012 and 2014 for two cities in East Malaysia, namely Kuching (Sarawak) and Kota Kinabalu (Sabah). Wind characteristics were analysed using only wind velocity and direction, while the level of outdoor thermal comfort was measured using Universal Thermal Climate Index (UTCI). The results showed that hourly average wind velocities for Kuching and Kota Kinabalu were 1.84 m/s and 2.15 m/s respectively while the highest average wind velocities was 10.1 m/s and 12.4 m/s respectively. No wind movement (i.e. 0 m/s) was recorded for both locations. The prevailing annual wind flow is generally from South-Southeast (150°) in Sarawak and from East-Southeast (110°) in Sabah. It was also found that both Kuching and Kota Kinabalu experienced strong and extreme heat stress conditions with UTCI levels of 44.8°C and 49.8°C respectively. Thus, it can be concluded that, East Malaysia faces strong and extreme heat stress conditions. This study is an original contribution on the subject of outdoor thermal environment in Malaysia, Further research to better understand outdoor thermal environmental problems is recommended.
  8. Farhana Ahmad Affandi, Mohd Yusoff Ishak, Nur Hamizah Samsudin
    Mining is one of the anthropogenic activities that can negatively affect the environment especially the waterways. Discharges from mining activities are usually in acidic state and containing elevated concentrations of metals. The exposure to these contaminants may cause several harmful effects not only to aquatic organisms but also to human health. The Whole Effluent Toxicity (WET) test was applied to evaluate the toxic effects of tin mining effluents to aquatic organisms. An acute toxicity test with zebrafish (Danio rerio) was conducted where fish was exposed to 3.13%, 6.25%, 12.5%, 25% and 50% effluent for 96 hours under static renewal test system. Effects of effluent exposure were determined using endpoints with mortality of median lethal concentration (LC50) value. Results indicated that the LC50 value of zebrafish when exposed, was 14.21% effluent. The physicochemical properties of the effluent were also evaluated in order to assess the cause-effect relationships of the effluent. The low pH values of the mine effluent might be the main reason contributing to the fish mortality. This approach provides additional information of tin mining effect on freshwater fishes as well as to human health.
  9. 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.
  10. Anis Adilah Abu Talib, Aidah Jumahat, Napisah Sapiai, Ahmad Shahrul Mohd Roslan
    This research investigated the wear properties of Carbon Nanotube (CNT) filled epoxy polymer and fiber reinforced composites. The CNT/epoxy composites with 0.5 wt% and 1.0 wt% CNT contents were mixed at 50°C for 1 hour at a speed of 400 rpm using mechanical mixer, while woven glass fiber reinforced polymer (GFRP) nanocomposites were fabricated using vacuum bagging technique. The effect of CNT on wear properties was evaluated using dry sliding abrasion wear test that used vitrified bonded silicon carbide as abrasive wheels. The mass loss and specific wear rate curves show that wear properties of epoxy polymer and GFRP composite systems were enhanced when CNT was added. Epoxy polymer and GFRP nanocomposites showed the highest wear resistance when CNT content was 1.0 wt% and 0.5 wt% respectively. The CNT-filled composite showed improvement till up to 78.9 % from its pure system. This suggested that the load transferability between CNT and epoxy was more effective in nanomodified systems than in its pure systems. Therefore, adding CNT improves the wear properties of epoxy polymer and woven GFRP composite.
  11. Athraa Iessa, Noor Izzri Abdul Wahab, Norman Mariun
    One of the concerns in power system preventive control and security assessment is to find the point where the voltage and frequency collapse and when the system forces a severe disturbance. Identifying the weakest bus in a power system is an essential aspect of planning, optimising and post-event analysing procedures. This paper proposes an approach to identify the weakest bus from the frequency security viewpoint. The transient frequency deviation index for the individual buses is used as the weakest bus identification as well as a frequency security indicator. This approach will help to determine the bus with the worst deviation, which helps to analyse the system disturbance, takes proper control action to prevent frequency failure, and most importantly, observes consumer frequency. The approach is applied to the WSCC 9 bus test system to show the feasibility of the method.
  12. Md Saad, W.M., Mohd Nor, N.A., Abdul Razak, H.R., Mat Salleh, M.S., Abdul Rasid, A., Hanifah, R.
    Ionising radiation (IR) has been extensively used as therapy and diagnostic modality to detect abnormalities inside a human body. Interaction between IR and cells can lead to production of free radicals. This study aims to evaluate radioprotective properties of 50% watermelon juice against low dose ionising radiation (LDIR)-induced stress in mice lung and liver tissues following 14 days of juice supplementation. Eighteen (18) ICR mice were randomly divided into three groups, negative control (Cx), radiation (Rx) and treatment group (Tx). The Cx group was treated with normal diet and filtered water while the Rx group was given a normal diet, filtered water and irradiated with 100 µGy x-ray; Tx group was fed a normal diet, 50% watermelon juice and irradiated with 100 µGy x-ray. After 14 days, level of superoxide dismutase (SOD), reduced glutathione (GSH) and malondialdehyde (MDA) in lung and liver tissues were evaluated. The SOD inhibition activity revealed a significant decrease in Rx and Tx compared with Cx (p
  13. Aliyu, Aliyu Danjuma, Go, Rusea, Hishamuddin Omar, Syazrin Syima Sharifuddin, Azroie Muhammad, Bashirah Fazli
    This study was conducted to determine the baseline water quality characteristics of a contaminated NAHRIM lake undergoing remediation by the constructed wetlands, based on the physico-chemical and biological parameters. The sampling was conducted for six months (May-October) in 2016 from 5 stations of the lake and analysed using APHA standard methods for water and wastewater analysis, while Malaysian water quality index (WQI) was used to calculate quality of the lake. The results showed that, the Conductivity, Dissolved Oxygen, NO3-N, NO2-N, PO4, Temperature, Turbidity, TDS, TSS, and Zn were under class I, while pH, B and COD were categorized under class II. NH3-N, BOD, Fe, Escherichia coli, Total coliform and Mn were categorized as class III. Moreover, Al was not given any classification under NWQS but their concentration did not exceed EPA guidelines. Furthermore, as compared to the water samples from the constructed wetlands that reported a class III WQI, the lake was observed to show an overall class II WQI. This is suggestive of the retaining and remedial role of the constructed wetlands being the first point of contact for the contaminants going to the lake. Thus the lake is suitable for recreational activities.
  14. Wu Diyi, Zulaiha Ali Othman, Suhaila Zainudin, Ayman Srour
    The water flow-like algorithm (WFA) is a relatively new metaheuristic algorithm, which has shown good solution for the Travelling Salesman Problem (TSP) and is comparable to state of the art results. The basic WFA for TSP uses a 2-opt searching method to decide a water flow splitting decision. Previous algorithms, such as the Ant Colony System for the TSP, has shown that using k-opt (k>2) improves the solution, but increases its complexity exponentially. Therefore, this paper aims to present the performance of the WFA-TSP using 3-opt and 4-opt, respectively, compare them with the basic WFA-TSP using 2-opt and the state of the art algorithms. The algorithms are evaluated using 16 benchmarks TSP datasets. The experimental results show that the proposed WFA-TSP-4opt outperforms in solution quality compare with others, due to its capacity of more exploration and less convergence.
  15. 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.
  16. Dazylah Darji, Ma'zam Md Said
    Epoxidised Natural Rubber (ENR) is now a commercially available polymer produced by chemical modification of natural rubber. Currently, three types of ENR are commercially available, and these are ENR 10, ENR 25, and ENR 50 with 10%, 25%, and 50% mol epoxidation, respectively. Studies on prevulcanisation of ENR 50 and postvulcanisation of the latex films were carried out. The objective of this study was to develop ENR 50 that could be dipped easily in coagulant dipping solution to produce dipped products. Several attempts were made by compounding prevulcanised ENR 50 at various sulphur levels ranging from 0.5 to 3.0 pphr. Using suitable coagulant dipping systems, ENR 50 film could be formed despite the high contents of non-ionic surfactant. It was found that the tensile strength of prevulcanised ENR 50 film decreased with the increase in the sulphur level. The results show that as level of sulphur increased, M300 also increased to an optimum value of 1.5 pphr of sulphur. For the postvulcanised ENR 50 film, however, the tensile strength increased and then decreased with the increasing sulphur level. Meanwhile M300 increased with the increasing postvulcanization time and sulphur level. The postvulcanisation of ENR 50 film seems to be a more effective way of increasing tensile properties than by prevulcanisation of ENR 50.
  17. Mohd Amran, Mohd Radzi, Zai Peng, Goh, Hashim, Hizam
    This paper presents a voltage flicker estimation based on a pair of inter-harmonics analysis method. The proposed algorithm is able to estimate flicker frequency and amplitude changes of a voltage waveform. The correlation of the pair of inter-harmonics, flicker frequency, and amplitude changes are presented and their formulas highlighted. .Experimental results indicate the amplitude of pair of inter-harmonics can detect the voltage flicker. Furthermore, the experimental results are compared with the measurement results obtained by using the Fluke power analyzer (Pst).
  18. Mohd Fazirul, M., Sharaniza, A.R., Norhazlin, J.M.Y., Wan Hafizah, W.J., Razif, D., Froemming, G.R.A., et al.
    Cryopreservation by vitrification has been widely used in Assisted Reproductive Technology (ART) to preserve embryos for an extended period of time. However, the effect of vitrification on development of the embryos is lacking. Therefore, understanding on vitrification effects on embryonic proteins, especially those involved in preimplantation development is crucial to provide high quality embryos for further usage. In this study, XIAP and S6K1 protein expressions following vitrification was investigated, since they have been implicated in diverse cellular processes including cell growth, migration, proliferation, differentiation, survival and development of preimplantation embryos via the PI3K pathway. Embryos were obtained from superovulated female ICR mice which were mated with fertile males. The embryos were harvested at the 2-cell stage and cultured until blastocyst stage. Blastocysts were then vitrified in ESF40 cryoprotectant. Western blot was carried out to determine the expression of XIAP and S6K1 proteins. The results showed the expression of XIAP and S6K1 significantly decreased in vitrified blastocyst compared to the control. This indicates that blastocyst vitrification may impact developmental competence through the activation of apoptotic pathways.
  19. Sui, Sien Leong, Lihan, Samuel, Hwa, Chuan Chia
    The abuse of antibiotics usage in bird industry has resulted in the emerging antibiotic resistant Enterococci worldwide which has posed a threat clinically to human health. The present study was to screen and identify the potential virulence agents in antibiotic resistance E. faecalis in bird industry in Borneo. Enterococcus bacteria collected from the birds’ faeces and indoor air inside ten birdhouses were identified to species level and their antibiotic resistance was checked using antibiotic susceptibility discs. Specific primers using PCR assay were intended for the detection of four potential virulence genes (ace, AS, efaA, gelE). Out of the thirty-seven Enterococci faecal bacteria, the prevailing bacteria found were Enterococcus qallinacum (51%), Enterococcus faecalis (35%) and Enterococcus harae (8%). The airborne bacteria were reported as Enterococcus faecalis (5%) and Enterococcus qallinacum (1%). Twenty-seven percent of isolates were reported to have Multiple Antibiotic Resistance (MAR) index ≥ 0.2 with 9 distinct resistance patterns formed. E. faecalis showed higher resistance to vancomycin. Virulence genes were successfully reported in the 15 E. faecalis isolates. Sixty-seven percent of isolates were detected positive for four virulence genes, 27% possessed three (AS, efaA, gelE) genes and 6% possessed two (ace, AS) genes. Antibiotic resistance and virulence genes detection were significantly correlated. These virulence genes or antibiotic resistance genes were important in the pathogenesis of E. faecalis infections.
  20. Ismail, A. F., Sapari, N., Abdul Wahab, M. M.
    Land development, especially construction works, increase storm water volumes and pollution loads into rivers and lakes. The temporary drainage system at construction sites, particularly during the construction stage discharges a large amount of pollutants that can damage the aquatic system of the receiving water bodies. The potential of vegetative swale to alleviate this problem was evaluated. The size of the constructed vegetative swale was 7cm deep, 400cm long and 15cm wide at the bottom, and 17cm wide at the top. The experiment was conducted batch wise by filling the storage tank with the run-off water from the construction site. The water was allowed to flow through a pipe into the retention basin to maintain uniform flow before it entered the swale. The study showed that the run-off infiltrated through the soil at a rate of 489.6 mm/hr. Samples of surface run-off and infiltration water were collected at the end and the bottom of the swale. The results indicate that chemical oxygen demand (COD), total suspended solid (TSS), turbidity, iron and zinc were reduced by 85.4%, 80.8%, 36.4%, 52.8% and 96.0%, respectively, by surface flow and 91.1%, 98.8%, 58.2% 55.5% and 98.1%, respectively, by infiltration. Removal of nitrate and phosphorus by the planted vegetation was 69.4% and 21.1%, respectively, by infiltration. However, nutrient removal by surface flow was negligible. In conclusion, the vegetative swale was able to improve the water quality of the storm water run-off from the construction site from Class V to Class III, according to the Interim National Water Quality Standards for Malaysia.
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