Displaying publications 61 - 80 of 839 in total

Abstract:
Sort:
  1. Kiing, Sie Cheong, Balasubramaniam, Jaya-Raj, Yiu, Pang Hung, Wong, Sie Chuong, Amartalingam, Rajan
    MyJurnal
    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.
  2. Abdalla A. Ab. Rashdi, Mohd Sapuan Salit, Khalina Abdan, Megat Mohamad Hamdan Megat
    MyJurnal
    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.
  3. Chieh, C.W., Asmawi Sanuddin, Reza Afshar, Aidy Ali
    MyJurnal
    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
  4. Intan S. Ismail, NorAkmar Ismail, Nordin Lajis
    MyJurnal
    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.
  5. Jaafar, M.S., Thanoon, Waleed A., Mohammed, T.A., Huda, A.M., Noorzaei, J.
    MyJurnal
    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.
  6. Mohd Ashraf Ahmad, Zaharuddin Mohamed
    MyJurnal
    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.
  7. Ee, G.C.L., Jong, V.Y.M., Sukari, M.A., Lee, T.K., Tan, A.
    MyJurnal
    Our continuing interest in anthraquinones from the Guttiferae family has led us to look at the genus Cratoxylum. A detailed chemical study on Cratoxylum aborescens resulted in the isolation of three anthraquinones, namely 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (1), vismiaquinone (2) and vismione (3). These compounds were identified using 1D and 2D NMR spectroscopy. This is the first report on the chemistry of Cratoxylum aborescens.
  8. Yeoh, S.J., Taip, F.S., Endan, J., Talib, R.A., Sita Mazlina, M.K.
    MyJurnal
    Aquaculture is a growing industry with a great potential towards the contribution of the country’s total
    fish requirement. Serious efforts have been done to develop and improve the production of fish by rearing high value fish in tanks or ponds. Under the Third National Agricultural Policy (1998-2010), the target is to annually produce 1.93 million tonnes of fish worth approximately RM8.3 billion by the year 2010. Consequently, the development of an automatic fish feeding machine can be very beneficial to the growth of the aquaculture industry. This device was developed to overcome labour problems in the industry and introduce a semi-automatic process in the aquaculture industry. It has the ability to dispense dried fish food in various forms such as pellets, sticks, tablets or granules into fish tanks or ponds in a controlled manner for a stipulated time. The automatic fish feeder is controlled by a digital timer and it is capable of feeding the fish in accordance with a pre-determined time schedule without the presence of an operator, and at a feeding rate of 250g/min. The feeder can be adjusted to the desired height and conveniently moved around to be positioned adjacent to the pond or tank. Meanwhile, its hopper can be covered and easily dissembled to change the size of the hopper to accommodate different capacities of feed. This automatic fish feeder can be implemented in aquaculture system to convenience to fish culturists.
  9. Al-Shamiry, Faisal Mohammed Seif, Desa Ahmad
    MyJurnal
    Natural ventilation is defined as the number of air exchanges per hour per unit floor area necessary
    to reduce high indoor air temperature and humidity. In addition, it maintains the concentration of carbon dioxide. Natural ventilation is preferred in mechanical system as the ventilation opening is built into the greenhouse, with lower construction cost and no energy and maintenance inputs are required. A mathematical model to quantify natural ventilation rates was developed and verified in large-scale greenhouse structures. For this purpose, four Naturally Ventilated Tropical Greenhouse Structures were designed and constructed at the Malaysian Agricultural Research and Development Institute (MARDI). These were single, double, triple, and quadruple span structures with floor areas of 500 m2, 1000 m2, 1500 m2 and 2000 m2, respectively. This paper presents the validation of a mathematical model which was developed to quantify natural ventilation rates which are very crucial to reduce high in-house temperature built up in the tropics. Regression equations of natural ventilation against wind speed were found to be Φw = 0.0632V, Φw= 0.0395V, Φw= 0.0316Vand Φw=0.0276V for the single, double, triple and quadruple spans, respectively. Meanwhile, coefficients of determination showed strong relationships between ventilation rate and wind speed, with R2 = 0.9999 for all structures. Larger floor area was found to have higher in-house temperature than smaller ones. Ventilation rate inside the single-span structure was found to be higher compared to the multi-span structures, which increased linearly with the increasing wind speed at the eaves of structure.
  10. Awal, M.A., Wan Ishaq, W.I., Bockari-Gevao, S.M.
    MyJurnal
    The present conventional (destructive) method used in determining LAI is laborious, difficult and time consuming. Thus, an image-based measurement using camera system with fish eye lens offers an alternative means for an accurate indirect measurement of LAI in oil palm. In this study, a methodology was developed to improve the leaf area index of the oil palm determination using hemispherical photography as an indirect method. A set of true LAI data, collected using the destructive method, were used as a reference to calibrate the LAI measurements obtained by the hemispherical photography. A good relationship (r = 0.85) was found between age of palm and hemispherical photographic LAI. However, the estimated LAI obtained by the hemispherical photographic method was underestimated as compared to the destructive method. Some means of calibration was necessary to determine the relationship between the actual LAI and the hemispherical photographic LAI. It was necessary to multiply the LAI value from 5 years to 16 years, by a clumping factor of 2.14 for 5 to 9 year old palms, 2.33 for 10 to 14-year old palms and 2.37 for above 15- year old palms to calculate the accurate LAI values. For palms which are less than 5 year old (i.e. 2 to 3 years in this study), the photography LAI value was equal to the calculated LAI value. This proposed that correction factors would solve this underestimation effect. In addition, two equations were also proposed to estimate the true LAI from the Photographic LAI for immature and mature oil palm plantation.
  11. Karimi-Googhari, Shahram, Huang, Yuk Feng, Abdul Halim B. Ghazali, Lee, Teang Shui
    MyJurnal
    Proper integrated management of a dam reservoir requires that all components of the water resource system be known. One of these components is the daily reservoir inflow which is the subject matter of this study, i.e. to establish predictions of what is coming in the next rainfall-runoff process over a catchment. The transformation of rainfall into runoff is an extremely complex, dynamic, and more of a non-linear process. The available six-year average daily rainfall data across the Sembrong dam catchment were computed using the well-known Theissen’s polygon method. Daily reservoir inflow data were extracted by applying the water balance model to the Sembrong dam reservoir. Modelling of relationship between rainfall and reservoir inflow data was done using feed-forward back-propagation neural networks. The final selected model has one hidden layer with 11 neurons in the hidden layer. The selected model was applied for an independent data series testing. Results in relation to specific climatic and hydrologic properties of a small tropical catchment suggested that the model is suitable to be used in forecasting the next day’s reservoir inflow. The efficiencies of the model Abtained indicated the validity of using the neural network for modelling reservoir inflow series.
  12. Dazylah Darji, Ma'zam Md Said
    MyJurnal
    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.
  13. Santiagoo, Ragunathan, Hanafi Ismail, Kamarudin Hussin
    MyJurnal
    The effect of polypropylene maleic anhydride (PPMAH) on tensile properties and morphology of polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr)/ rice husk powder (RHP) composites has been studied. The composites were prepared through melt mixing at 180ºC for 9 minutes using 50 rpm rotor speed. The specimens were analyzed using different techniques, namely tensile test and Scanning Electron Microscopy (SEM). The results obtained showed that the tensile strength and Young’s modulus of the modified composites were increased, while the elongation at break showed the opposite trend as compared with the unmodified composites. The morphology results support the tensile properties and these indicated a better interaction between the filler and matrix with the presence of PPMAH as a compatibilizer.
  14. Kamaruzzaman, B.Y., Noor Azhar, M.S., Norhizam, H.A.G., Willison, K.Y.S.
    MyJurnal
    Ocean sediments give information on the paleoclimatic evolution in the geological past which gives detailed information on both the age of the sediments and both paleoceanographic and paleoclimatic conditions during sedimentation. One possible way to date sediments is with 210Pb method which can be used to date sediments up to 100 years. In this study, two core samples labelled as JB15 and JB17 were collected using pledging corer, analysed and measured for the activity of 209Po and 210Po using the alpha spectrometer. Applying the methods, average sedimentation rates for JB15 and JB17 were calculated as 0.38 cmyr-1 and 0.43 cmyr-1, respectively. Assuming that the sedimentation rate values are accurate, this might imply that the sediments at the depth of 30 cm were deposited 70 years ago.
  15. Jakarni, F.M., Muniandy, R., Hassim, S., Mahmud, A.R.
    MyJurnal
    Stone Mastic Asphalt (SMA) is one type of asphalt mixture which is highly dependent on the method
    of compaction as compared to conventional Hot Mix Asphalt (HMA) mixture. A suitable laboratory compaction method which can closely simulate field compaction is evidently needed as future trend
    in asphalt pavement industry all over the world is gradually changing over to the SMA due to its excellent performance characteristics. This study was conducted to evaluate the SMA slab mixtures compacted using a newly developed Turamesin roller compactor, designed to cater for laboratory compaction in field simulation conditions. As the newly developed compaction device, there is a need for evaluating the compacted slab dimensions (which include length, width, and thickness), analyzing the consistency of the measured parameters to verify the homogeneity of the compacted slabs and determining the reliability of Turamesin. A total of 15 slabs from three different types of asphalt mixtures were compacted, measured, and analyzed for their consistencies in terms of length, width, and thickness. Based on study the conducted, the compacted slabs were found to have problems in terms of the improperly compacted section of about 30 mm length at both ends of the slabs and the differences in the thickness between left- and right-side of the slab which were due to unequal load distribution from the roller compactor. The results obtained from this study have led to the development of Turamesin as an improved laboratory compaction device.
  16. Luqman Chuah Abdullah, Saidatul Shima, J., Choong, Thomas S.Y., Muhammad
    MyJurnal
    A series of batch laboratory studies were conducted to investigate the suitability of activated carbon SA2 for the removal of cadmium ions and zinc ions from their aqueous solutions. The single component equilibrium data were analyzed using the Langmuir and Freundlich isotherms. Overall, the Langmuir isotherm showed a better fitting for all adsorptions under investigation in terms of correlation coefficient and error analysis (SSE only 18.2 for Cd2+ and 47.95 for Zn2+). As the binary adsorption is competitive, extended Langmuir models could not predict the binary component isotherm well. The modified extended Langmuir models were used to fit the binary system equilibrium data. The binary isotherm data could be described reasonably well by the modified
    extended Langmuir model, as indicated in the error analysis.
  17. Islam, Md. Syedul, Desa Ahmad
    MyJurnal
    Experiments were conducted to determine the field and economic performances of machines and techniques for crop establishment in lowland paddy in Bangladesh. In machine seeded field, the crops were grown in rows to allow the operation of rotary type weeder for weed control. In hand broadcasted field, crops were not arranged in rows and weed control operation was therefore done through traditional means. Results obtained showed that the effect of rice seeding techniques, using pre-germinated rice seed of BR-1 variety on the effective field capacity, was highly significant. The work rate of hand broadcasting was found to be one to one and a half times faster than that of seeding by manually driven drum type row seeder. Field efficiency of hand broadcasting was about 90 percent, and this was found to be significantly higher than those of machine seeding which ranged from 70-80 percent at both seed rates, since no time was lost in turning. BRRI modified drum type row seeder, with a seeding rate of 60 kg/ha, was shown to be better for an optimum crop yield. Based on partial budget analysis, a farmer can save about US$53.34 per hectare in a year using the BRRI modified drum type row seeder, followed by a rotary weeder as compared to hand seeding, followed by hand weeding.
  18. Kaida Khalid, W. Mohd. Daud W. Yusoff, Jumiah Hassan
    MyJurnal
    Dielectric properties of natural rubber Hevea brasiliensis latex were measured at frequencies 0.2 to 20 GHz, at temperatures of 2, 15, 25, 35, and 50oC and around 30-98% moisture content. Measurements were done using open-ended coaxial line sensor and automated network analyzer. As expected, results showed that dielectric constant increased with increasing moisture. From 0.2 to 2.6 GHz, the losses were governed by conductive losses but for frequencies greater than 2.6 GHz, these were mainly due to dipolar losses. The former is due to conducting phases in hevea latex, while the latter is mainly governed by the orientation of water molecules. The results were analyzed at 2.6, 10, and 18 GHz, respectively. These were then compared with the values predicted by the dielectric mixture equations recommended by Weiner, Bruggeman and Kraszewski. All the measured values were found to be within the Weiner’s boundaries and close to the upper limit of Weiner’s model. It is also close to the predicted values of Bruggeman’s model with a/b = 0.1. All the models including Kraszewski are suitable for predicting the dielectric properties of hevea latex for frequencies 2.6 to 18 GHz, moisture content 30 to 98% and temperatures 2 to 50oC.
  19. Mohebpour, M.R., Adznan, B.J., Saripan, M.I.
    MyJurnal
    In this paper, a new method known as Grid Base Classifier was proposed. This method carries the advantages of the two previous methods in order to improve the classification tasks. The problem with the current lazy algorithms is that they learn quickly, but classify very slowly. On the other hand, the eager algorithms classify quickly, but they learn very slowly. The two algorithms were compared, and the proposed algorithm was found to be able to both learn and classify quickly. The method was developed based on the grid structure which was done to create a powerful method for classification. In the current research, the new algorithm was tested and applied to the multiclass classification of two or more categories, which are important for handling problems related to practical classification. The new method was also compared with the Levenberg-Marquardt back-propagation neural network in the learning stage and the Condensed nearest neighbour in the generalization stage to examine the performance of the model. The results from the artificial and real-world data sets (from UCI Repository) showed that the new method could improve both the efficiency and accuracy of pattern classification.
  20. Mohammad, Thamer Ahmad, Mohd. Razali Abdul Kadir, Megat Johari Megat Mohd. Noor, Ahmad Husaini Sulaiman
    MyJurnal
    Part of the Seremban flood mitigation project in the state of Negeri Sembilan, Malaysia is to mitigate
    the flood at Jalan Rasah. The mitigation is planned to be implemented in packages. Package I and Package II of River Anak Air Rasah are parts of the project work. In these packages, wider and deeper concrete sections for the river are constructed. The existing undersized culverts were replaced by bigger reinforced concrete box culverts. The size of the box culverts was based on 100-years average reoccurrence interval (ARI). One of these culverts intersected with a rail line connecting Singapore and Malaysia. Trenchless jacking technique was used to lay the box culvert. The total length of the box culvert jacked under the railway line is 33 m, whereas the total width of the twin box culvert is 7.8 m with a total height of 3 m. This was the first time that the trenchless jacking techniques were used for the urban flood mitigation purpose in Malaysia, and it is mainly used to minimise traffic disruption. This study reports the success of using jacking technique in the development of the flood mitigation program of DID in Negeri Sembilan. Among other things, it explains significant performance of the technique under local conditions and experiences gained towards the advancement of tunnelling and trenchless technology.
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links