Displaying publications 1 - 20 of 173 in total

  1. Omar, A.R.
    ASM Science Journal, 2011;5(1):71-72.
    The government’s science and technology (S&T) apparatus is now in active consultation to formulate the third national S&T policy (NSTP3) and I have been involved in some of these meetings and have benefitted from them. In an earlier article (New Straits Times, 9 July 2011, p. 18) I had briefly described the two previous policies and given some thought on what the essentials of the NSTP3 should be. I am now offering some further thoughts on the subject. (Copied from article).
  2. Rahman, M.M., Nor, S.S.M., Rahman, H.Y.
    ASM Science Journal, 2011;5(1):11-18.
    Warm compaction is an advanced manufacturing technique which consists of two consecutive steps, i.e. powder compaction at above ambient temperature and sintering in a controlled environment. Due to the relative movement between the powder mass and die wall as well as sliding among powder particles, frictional force is generated during the compaction stage. Admixed lubricant is used during the compaction step in order to minimize friction and hence improve the uniformity of the density of distribution inside the component. However, during the sintering process, trapped lubricant is often found to be burnt out hence leaving pores or voids which result in the lower strength of the final products. Warm compaction was initiated in the nineties, however not much information has been published about the effects of lubrication on the quality of the components produced through this route. Therefore, this paper presents the outcome of an experimental investigation about the effects of lubrication on manufacturing near-net shape components through the warm compaction route. Iron powder ASC 100.29 was mixed mechanically with zinc stearate to prepare the feedstock. Mixing time, weight percentage of lubricant content and compaction temperature were varied during green compact generation while sintering temperature, heating rate and holding time were manipulated during sintering. The relative densities and strengths of the final products were investigated at every compaction as well as sintering parameter. The results revealed that lubrication could provide significant effects at the compaction temperature of 180ºC while no significant effect of lubrication was observed during sintering. The suitable lubricant content was found to be 0.4 wt% and mixing time was around 30 min and the sintering temperature was around 990ºC.
  3. Fazliah, S.N., Jaafar, S., Shamsuddin, S., Zainudin, Z., Hilmi, A.B., Razila, A.R., et al.
    ASM Science Journal, 2010;4(1):1-14.
    Stem cells from human extracted deciduous teeth (SHED) have the ability to multiply much faster and double their population in culture at a greater rate, indicating that it may be in a more immature state than other type of adult stem cells. Mesenchymal stem cells (MSC) from human primary molars were isolated and cultured in media supplemented with 20% fetal bovine serum. The MSCs were confirmed using CD 105 and CD 166 and the identification of the osteoblast cells were done using reverse transcriptase polymerase chain reaction (RT-PCR) analysis. Differentiated osteoblast cells (DOC) were characterized by alkaline phosphotase and von Kossa staining followed by immunocytochemistry staining using osteocalcin and osteonectin antibodies. Further validation of SHED was done by RT-PCR to detect the presence of insulin-like growth factor 2 (IGF-2) and discoidin domain tyrosine kinase-2 (DDTK-2) transcripts, while the presence of Runx-2 mRNA was used to characterize DOC. The results showed that SHED was found positive for CD 105 and CD 166 and could differentiate into osteoblast, bone forming cells. The findings revealed the presence of distinct MSC population which had the capability to generate living human cells that could be a possible source for tissue engineering in the future.
  4. Ramesh, S., Shanti, R., Chin, S.F.
    ASM Science Journal, 2011;5(1):19-26.
    In this present study, a series of polymer electrolyte thin films were synthesized by incorporating different ratios of lithium triflate (LiCF3SO3) in a low molecular weight polyvinyl chloride (PVC) matrix by the solution casting technique. The incorporation of LiCF3SO3 suppressed the high degree of crystallinity in PVC enabling the system to possess an appreciable ionic conductivity. The ionic conductivity of the samples, with different LiCF3SO3 content, was determined by the aid of ac impedance spectroscopy. The highest ionic conductivity of 4.04  10–9 S cm–1 was identified for the composition of PVC: LiCF3SO3 (75:25). Further understanding of the ionic conductivity mechanism was based on temperature-dependent conductivity data which obeyed Arrhenius theory, indicating that the ionic conductivity enhancement was thermally assisted. The possible dipole-dipole interaction between the chemical constituents was confirmed with changes in cage peak, analysed using Fourier transform infrared spectroscopy.
  5. Jamuna, K., Noorsal, K., Zakaria, F.A., Hussin, Z.H.
    ASM Science Journal, 2010;4(1):41-47.
    Introducing CO2 flux as the carbonate source had an effect on the carbonate content of carbonate apatite (CAp) synthesized by solid state reaction. The reactants were CaCO3 and beta-tricalcium phosphate (β-TCP) and the heat treatment in air was performed at 1250ºC followed by instant cooling in CO2 flux for temperatures ranging from 800ºC room temperature (RT) . The influence of CO2 flux at various temperature drop differences in the cooling process (1250ºC RT, 1250ºC–500ºC, 1250ºC–600ºC, 1250ºC–700ºC, and 1250ºC–800ºC) was tested to optimize the carbonation degree and subsequent effects on the physical and mechanical properties of CAp. Thermally treated samples revealed an increasing degree of carbonation, achieving a maximum of 5.2 wt% at the highest (1250ºC RT) and a minimum of 2.7 wt% at the lowest (1250ºC–800ºC) temperature drop differences, respectively. This showed that the carbonate content was correlated with the increase in exposure to CO2 flux. However, consistent compressive strength, tensile strength, density and porosity were observed against increasing temperature drop differences which indicated that the degree of carbonation exerted no influence on the physical and mechanical properties of CAp. This method enabled the synthesis of solid state CAp simply by exposing calcium phosphate mixtures to CO2 flux. It also allowed the control of carbonate content for desired medical applications.
  6. Dinesh, S.
    ASM Science Journal, 2010;4(1):62-73.
    Studies conducted on the various geometric properties of skeletons of water bodies have shown highly promising results. However, these studies were made under the assumption that water bodies were static objects and that they remained constant over time. Water bodies are actually dynamic objects; they go through significant spatio-temporal changes due to drought and flood. In this study, the characterization of skeletons of simulated drought and flood of water bodies was performed. It was observed that as the drought level increased from 1 to 9, the average length of the skeletons decreased due to reduction in the size of the water bodies and increase in the number of water bodies. As the drought level increased from 9 to 15, the average length of the skeletons increased further due to vanishing of small water bodies. Flood caused an increase in the average length of the skeletons due to merging of adjacent water bodies. Power law relationships were observed between the average length of the skeletons of the simulated drought/flood and the level of drought/flood. The scaling exponent of these power laws which was named as a fractal dimension, indicated the rate of change of the average length of the skeletons of simulated drought/flood of water bodies over varying levels of drought/flood. However, errors observed in the goodness of fit of the plots indicated that monofractals were not sufficient to characterise the skeletons of simulated drought and flood of water bodies. Multifractals and lacunarity analysis were required for more accurate characterisation.
  7. Kamarudin, K.S.N., Chieng, Y.Y., Hamdan, H., Mat, H.
    ASM Science Journal, 2010;4(1):29-40.
    Ordered microporous NaY zeolite and mesoporous copper oxide are high performance material as catalysts and adsorbents. The copper oxide-NaY zeolite modification in combination of their physicochemical properties could provide excellent opportunities for the creation of new gas adsorbents. In this study, modified NaY zeolite properties and methane adsorptive characteristics were investigated by dispersing copper oxide onto the NaY zeolite structure using the thermal dispersion method. The structures of the copper oxide modified zeolites were characterized by powder X-ray diffraction and Micromeritics ASAP 2000, while the methane adsorption characteristics were analyzed using a thermogravimetric analyzer. The results revealed that types of copper oxide, copper oxide loading concentration, calcination temperature and calcination time greatly affected the modified zeolite structure and gas methane adsorption characteristics.
  8. Ghazally Ismail
    ASM Science Journal, 2011;5(1):73-74.
    Human activity has ‘very likely’ been the primary cause of global warming since the start of the Industrial Revolution (18th–19th century). As a new player in industrial transformation, Malaysia can choose to ignore the warnings of global warming. blame. This may not augur well. Release of greenhouse gases have been categorically linked to climate change and global warming. In her march towards industrialization, Malaysia too has contributed to the release of greenhouse gases. Apart from those arising from natural sources, the industrial sector in Malaysia also releases other types of gases such as the fluorocarbons. This is evident from the worsening air quality in some of our cities. (Copied from article).
  9. Rohana, H.
    ASM Science Journal, 2011;5(1):1-10.
    Current National Design Specification (NDS 2005) provides the guideline to design timber joints strengthened with steel fasteners. This study investigates the possibility of using NDS 2005 to estimate the load-carrying capacity of timber joints fastened with Glass Fibre Reinforced Polymer (GFRP) dowel. Double shear timber joint fastened with steel dowels were tested to validate the joints fastened with GFRP using 1.27 cm diameter dowels. Tests were also conducted to determine the dowel bearing strength of wood and dowel bending strength of GFRP and steel. The failure modes of all tests were observed and recorded. Results showed that NDS (2005) successfully estimated the failure mode and was capable of predicting the joint load-carrying capacity when fastened with a GFRP dowel and this was well validated by the load carrying capacity of a steel dowel.
  10. Ahmad Zaidee Laidin, Loganathan, P.
    ASM Science Journal, 2011;5(1):77-77.
    Awareness and sensitivity on the subject of green technology are currently commanding the attention of the world in the light of rising energy costs and the threat of global warming. Many countries are now recognizing the benefits of researching into and using green technology to reduce their carbon and water footprints and to minimize waste. (Copied from article).
  11. Islam, M.R., Muthuraju, S., Tarmizi, C.H., Zulkifli, M.M., Osman, H., Mohamad, H., et al.
    ASM Science Journal, 2012;6(2):95-102.
    Epilepsy is a neurological disorder characterized by recurrent seizures resulting from excessive abnormal electrical discharges in the brain. Medicinal plants may play an invaluable role to discover the new antiepileptic drugs. The aim of the present study was to investigate the anticonvulsant activity of α-terpineol isolated from Myristica fragrans Hountt. The α-terpineol showed a significant inhibition of the seizure episodes and spikes in absence seizures model of Genetic Absence Epilepsy Rats from Strasbourg (GAERS) rats by using electroencephalography records. It showed dose-dependent anticonvulsant activity that was comparable to the known antiepileptic drug of diazepam. It showed a rapid onset and relatively short duration of anticonvulsant effects. The present findings suggest that α-terpineol might possess antiepileptic activities against the partial seizures of human because it prevented seizures in well-established genetic absence seizure animal model of GAERS rats.
  12. Abdul-Kadir, M.A., Ariffin, J.
    ASM Science Journal, 2012;6(2):128-137.
    This paper reviews the advances made on studies related to bank erosion. Bank erosion has been an area of interest by researchers in geological, geotechnical, hydraulic, hydrology and river engineering disciplines. With anticipated global challenges from climate change impacts, bank erosion studies could support challenges faced in ensuring sustainable environmental management. The evolution in the theoretical and laboratory findings have led to the advances in bank erosion and contributed to new knowledge in the said field. This review summarises the findings of previous investigators including measurements approach and prediction of rates of bank erosion through the use of physical models and numerical approach.
  13. Monajemia, H., Daud, M.N., Zain, S.M., Wan Abdullah, W.A.T.
    ASM Science Journal, 2012;6(2):138-143.
    Finding a proper transition structure for the peptide bond formation process can lead to a better understanding of the role of the ribosome in catalyzing this reaction. A potential energy surface scan was performed on the ester bond dissociation of the P-site aminoacyl-tRNA and the peptide bond formation of P-site and A-site amino acids. The full fragment of initiator tRNAi met attached to both cognate (met) and non-cognate (ala) amino acids as the P-site substrate and the methionine as the A-site amino acid was used in this study. Due to the large size of tRNA, ONIOM calculations were used to reduce the computational cost. This study illustrated that the rate of peptide bond formation was reduced for misacylated tRNA without the presence of ribosomal bases. This demonstrated that there were indeed specific structural interactions involving the amino acid side chain within the tRNAi met.
  14. Reza, F., Begum, T., Ahmed, A.L., Omar, H., Muzaimi, M., Abdullah, J.M.
    ASM Science Journal, 2012;6(1):39-45.
    The human brain generates different oscillations at different frequencies during various consciousness levels. When these brain waves synchronize with exogenous rhythmic stimulation, the brain experiences strong, yet relaxing emotion that could be involved in the formation of memory. We investigated the character of rhythmic oscillatory dynamics by electroencephalography (EEG) of subjects listening to a short verse of the Holy Quran compared to resting and Arabic news listening. The mean power amplitudes of each frequency band for wavelet-based time-frequency analysis were obtained from 5000 ms of segmented EEG recordings during rest, news and Quran listening conditions. The time series analysis of power from each of three conditions in each frequency band from the grand averaged data was then subjected to autocorrelation study. The results showed significant cyclic overall trends of increasing and decreasing patterns of power in the low frequency brain wave oscillation of different head regions especially global, frontal and temporal sites. These results provided a basis for prediction of the periodicity of the power of the oscillatory brain dynamics of delta and robustly in theta regions which occurred during Quran listening. Despite several limitations, our data offered a plausible scientific basis to the emotional induction during Quran listening that mimics recognized as data from music listening studies. This offered a promising perspective for future studies in translational neurophysiological, cognitive and biofeedback on Quran listening to modify brain behaviour in health and disease.
  15. Devaraj, V., Zairossani, M.N.
    ASM Science Journal, 2012;6(1):15-21.
    Malaysia is the world’s top manufacturer of examination and surgical natural rubber (NR) gloves, exported mainly to the USA and Europe. The glove manufacturing process yields effluent which must be treated to comply with the stringent regulatory requirements imposed by the Malaysian Department of Environment. To make glove manufacturing an eco-friendly process, efforts are geared towards minimizing and utilizing waste or converting it into raw material for making value-added products. Waste generated from the glove industry is mainly rubber sludge which is obtained from the chemical flocculation stage of the effluent treatment process and consists of mainly rubber, remnants of compounding ingredients and water. R&D work by the Malaysian Rubber Board on waste utilization and resource recovery investigations have revealed many uses for this sludge. This paper briefly outlines only one of the many options available, which is the conversion of the sludge into sludge derived fuel (SDF). Preliminary study has identified three formulations of SDF with calorific values (CV) exceeding 16 000 kJ/kg, matching a good grade coal. This was considered as promising results which warrant explorative work for further increasing the CV of SDF to turn it into a viable fuel substitute in the latex products manufacturing industry and subsequently apply for a Clean Development Mechanism status to generate income.
  16. Low, C.Y., Hii, S.L., Leong, L.K., Yim, Y.Y., Tan, H.W.
    ASM Science Journal, 2012;6(1):61-66.
    Cassava starch was used as feedstock for production of bioethanol by Saccharomyces cerevisiae. The cassava starch was hydrolyzed using commercial α-amylase and glucoamylase enzymes followed by a batch ethanol fermentation process using saccharified starch slurry. By using 110 g/L of reducing sugar from saccharified starch slurry, the ethanol yield was promising with maximum ethanol concentration of 20.6 g/L recorded after 55 hours of cultivation process. Three different models - the Logistic model, Luedeking-Piret-like equation and Gompertz equation - were used to characterize and explain the cell growth, reducing sugar consumption and production formation, respectively. The kinetic parameters were estimated by fitting the experimental data to the proposed models using non-linear regression analysis. The correlation coefficient r2 values for the Logistic model, Luedeking-Piret-like equation and the Gompertz equation were 0.994, 0.996 and 0.990, respectively. The high correlation coefficient values indicate that the proposed models were able to describe the ethanol fermentation process.
  17. Sugandi, G., Majlis, B.Y.
    ASM Science Journal, 2012;6(2):122-127.
    Since its invention, polyimide (PI) has been widely used in micro-electro-mechanical system (MEMS) devices. For fabrication, the PI membrane, PI-2723 HD-Microsystems was used as the membrane material due to its Young's modulus of 2.7 GPa and its film thickness could easily be controlled by changing the speed of the spin coater system. The application PI as membrane structure on silicon wafers therefore gave a much better mechanical performance then conventional membranes made of silicon dioxide (SiO2) or silicon nitride (Si3N4) layers. The fabrication of PI membrane was the same as for SiO2 and Si3N4 membranes; the basic step was to etch a side of the silicon wafer using wet anisotropic etching. This paper proposes an effective process for fabrication of PI membrane with f ast and little supervision. In this process, a dual step process was wet anisotropic etching of single crystal silicon using pottasium hydroxyl (KOH) with different concentrations and temperature processes. For the first process, 45% KOH under boiling temperature was used to etch at least 90%–95% of the silicon. In the second process, the silicon was submerged in 45% KOH with temperature at 70ºC–80ºC to etch away the residual silicon until a clean and transparent PI membrane was achieved. Using this method, the fabrication of PI membrane could be generated fast.
  18. Bong, C.H.J., Mah, D.Y.S, Putuhena, F.J., Said, S., Bustami, R.A.
    ASM Science Journal, 2012;6(1):47-60.
    Hydraulics simulation can be used as a supporting tool for planning and developing a framework, such as Integrated Flood Management for river management. To demonstrate this, a hydraulics model for the Sarawak River Basin was run using InfoWorks RS software by Wallingford Software, UK. InfoWorks River Simulation (RS) was chosen because its applicability has been proven and widely used to model Malaysian rivers. The extraction of computed floodwater level and flood maps for different time intervals would produce the rate of floodplain submergence from river bank level. This information could be incorporated into a logical framework to support decisions on flood management measures. Thus, hydraulics models can be used as tools to provide the necessary decision parameters for developing logical frameworks which would act as to guide the planning when it involved various stakeholders’ participation.
  19. Mazlina, M.K., Che Su, M.S.
    ASM Science Journal, 2012;6(1):31-37.
    A 'green tyre' concept has the advantage of low rolling resistance, improved wet grip and enhanced handling. It has been reported that 3% decrease in rolling resistance is equivalent to 1% fuel saving, thus giving the 'green tyre' economic benefits and customer satisfaction. In this study, epoxidised natural rubber (ENR) compounds containing various loading of silica filler were prepared. The processibility and viscoelastic properties were investigated using the rubber processing analyser and Mooney viscometer. Results showed that the properties were adversely affected by the poor dispersion of silica as supported by the bound rubber measurement. In addition, a reversion in the cure behaviour was also observed as the curing temperature was increased to 170ºC.
  20. Abraham, Martin
    ASM Science Journal, 2012;6(1):67-70.
    The pursuit, initiation and establishment of multi-stakeholder partnerships, including with the private sector, is often a critical component of attaining and achieving the success and sustainability of many projects the world over. However, the soliciting and securing of socially, economically and environmentally constructive engagements between the private sector on the one hand, and the NGOs, CBOs and local communities on the other hand, is in reality much easier said than done. Notably, since most private sector corporations undoubtedly tend to leave behind various "ecological footprints", differing only in their size and depth, stemming from their respective forms and functions, and their ensuing impacts and implications. The interplay between the civil society and the private sector, especially for resource mobilization. (Copied from article).
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