Displaying publications 1 - 20 of 173 in total

Abstract:
Sort:
  1. Mahdi, M.A., Md. Ali, M.I., Ahmad, A., Zamzuri, A.K.
    ASM Science Journal, 2008;2(2):123-127.
    MyJurnal
    In this paper a study on the wideband double-pass Raman fibre amplifier with mirror as the pump reflector is reported. The pump lights at 1435 nm and 1455 nm were launched in a co-directional manner with respect to the input signal. The double-pass direction of the signal was achieved through a fibre loop mirror constructed using an optical circulator. It was shown that multiple signal amplification was achieved without any disturbance of stimulated Brillouin scattering.
  2. Mohd Razali Md Razak, Zaleha Kassim
    ASM Science Journal, 2018;11(2):76-85.
    MyJurnal
    Information on feeding behaviour of tropical horseshoe crabs, Tachypleus gigas (M¨uller, 1785) is still scanty compared to Limulus polyphemus (Linnaeus, 1758). Foods condition such as decayed, sheltered and etc., would substantially influence the edibility of food by the T. gigas. However, horseshoe crabs might have specific behaviour to manipulate the foraged food. The aim of this paper was to investigate the feeding mechanism of T. gigas toward different feed conditions. Experiments were conducted inside a glass tank. A total of 30 males and females respectively were introduced to five different natural potential feeds, namely, gastropods (Turritella sp.), crustacean (Squilla sp.), fish (Lates calcarifer ), bivalve (Meretrix meretrix ) and polychaete (Nereis sp.). We have manipulated the condition of introduced feed based on the several potential foods conditions in nature such as sheltered (protected with shell, hard outer skin or host tube), unsheltered and decayed before introduced the feeds to the crabs. In present study, female crabs took shorter response period towards surrounding feed compared to males. Overall, they prefer to consume freshly dead feeds and would totally reject the sheltered feeds, such as, shell, hard outer skin and tube host. Male crabs have particular feeding behaviours to manipulate the edibility of the decayed feeds. Detailed experiments on the feeding mechanism of T. gigas could provide more information on their foraging activity in the wild.
  3. Mohd Razali Md Razak, Zaleha Kassim
    ASM Science Journal, 2018;11(2):56-66.
    MyJurnal
    Nowadays, the numbers of wild horseshoe crab harvested for study are increasing. However, general information on Tachyplues gigas satiation level, gut transit time, defecation pattern and acclimation period in captivity during holding period are still scanty. The aims of this study are to identify T. gigas food intake, gut transit time and defecation pattern during the rearing period by introducing the crabs with gastropod (Turritella sp.), crustacean (Squilla sp.) and bivalve (Meretrix meretrix ) in several feed ratios; 0.2%, 0.6%, 1.0%, 1.4%, 1.8% and 2.2% expressed of crabs’ body weight. The defecation of T. gigas was monitored for every three hours after being fed to measure their gut transit time and defecation pattern. Male crabs did not significantly eat until two weeks in captivity, while the females started to eat in the early first week after being harvested from the wild. The satiation levels of the females (gastropod: 1.8%±0.04; crustacean: 1.7%±0.08; bivalve: 1.8%±0.06) were significantly higher than the males’ (gastropod: 1.7%±0.08; crustacean: 1.4%±0.02; bivalve: 1.6%±0.05) for all feed types. Gut transit time of the males were significantly longer than the females’. Male crabs took shorter time (1±0 hr) to achieve their satiation than female crabs (2±0 hrs). This study provides useful information for T. gigas rearing activity and for designing a better rearing system.
  4. Zakri, A.H.
    ASM Science Journal, 2009;3(2):200-202.
    MyJurnal
    Recent studies by the United Nations University - Institute of Advanced Studies (UNU-IAS) demonstrate that bioprospecting is taking place in Antarctica and the Southern Ocean and that related commercial applications were being marketed. The bioprospectors’ interest in Antarctica stems from two reasons. First, the lack of knowledge surrounding Antarctic biota provides opportunities to discover novel organisms of potential use to biotechnology. Second, Antarctica’s environmental extremes, such as cold temperatures, extreme aridity and salinity present conditions in which biota have evolved unique characteristics for survival (UNU-IAS 2003). Thus bioprospecting opportunities include, inter alia, the discovery of novel bioactives in species found in cold and dry lithic habitat, novel pigments found in hyper-saline lakes and antifreezes in sea-lakes (Cheng & Cheng 1999).
  5. Devaraj, V., Zairossani, M.N.
    ASM Science Journal, 2012;6(1):15-21.
    MyJurnal
    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.
  6. Omar, N.Y.M., Rahman, N.A., Zain, S.M.
    ASM Science Journal, 2009;3(1):77-90.
    MyJurnal
    Computational chemistry is a discipline that concerns the computing of physical and chemical properties of atoms and molecules using the fundamentals of quantum mechanics. The expense of computational chemistry calculations is significant and limited by available computational capabilities. The use of high-performance computing clusters alleviate such calculations. However, as high-performance computing (HPC) clusters have always required a balance between four major factors: raw computing power, memory size, I/O capacity, and communication capacity. In this paper, we present the results of standard HPC benchmarks in order to help assess the performance characteristics of the various hardware and software components of a home-built commodity-class Linux cluster. We optimized a range of TCP/MPICH parameters and achieved a maximum MPICH bandwidth of 666 Mbps. The bandwidth and latency of GA put/get operations were better than the corresponding MPICH send/receive ones. We also examined the NFS, PVFS2, and Lustre parallel filesystems and Lustre provided the best read/write bandwidths with more than 90% of those of the local filesystem.
  7. Lashgari, V.A., Yoozbashizadeh, H.
    ASM Science Journal, 2007;1(1):37-41.
    MyJurnal
    Silicon, as the most important electronic material, has a lot of applications in the electronic industry and this includes the use of silicon in solar cells. One of the solar grade silicon production processes is the use of acid leaching for the removal of metallic impurities from silicon. The main advantage of this process for silicon purification is that it is based on a low temperature process. The purification of metallurgical grade silicon by acid leaching was studied as a function of time, temperature and etching. Based upon experimental results and under optimum conditions, it was possible to remove 41%, 71% and 25% of iron, calcium and aluminum respectively, with the use of aqua regia.
  8. Durairaj, R., Leong, K.C., Chia Wea, L., Wong, M.C.
    ASM Science Journal, 2011;5(2):109-114.
    MyJurnal
    Lead-free solder paste printing processes account for the majority of assembly defects in the electronic manufacturing industry. In the stencil printing process, the solder paste must be able to withstand low and high shear rates which result in continuous structural breakdown and build-up. This study investigated the effect of the addition of nickel and platinum powders to the thixotropic behaviour of lead-free Sn/Ag/Cu solder pastes using the structural kinetic model. A hysteresis loop test and constant shear test were utilized to investigate the thixotropic behaviour of the pastes using parallel plate rheometry at 25ºC. In this study, the shear rates were increased from 0.01 s–1 to 10 s–1 and the second curve was a result of decreasing the shear rate from 10 s–1 to 0.01 s–1. For the constant shear test, the samples were subjected to five different shear rates of 0.01s–1, 0.1s–1, 1s–1, 10s–1 and 100s–1. The constant shear rate test was designed to study the structural breakdown and build-up of the paste materials. From this investigation, the hysteresis loop test was shown to be an effective test method to differentiate the extent of structural recovery in the solder pastes. All the pastes showed a high degree of shear thinning behaviour with time. This might be due to the agglomeration of particles in the flux that prohibited paste flow under low shear rate. The action of high shear rate would break the agglomerates into smaller pieces which facilitated the flow of pastes, thus viscosity was reduced at high shear rate.
  9. Tan, C.T., Chua, K.B., Wong, K.T.
    ASM Science Journal, 2009;3(1):91-96.
    MyJurnal
    The Nipah virus was first discovered in 1999, following a severe outbreak of viral encephalitis among pig farm workers in Malaysia. The virus was thought to have spread from Pteropus bats to pigs, then from infected pigs to humans by close contact. Mortality of the disease was high at about 40%. The main necropsy finding was disseminated microinfarction associated with vasculitis and direct neuronal involvement. Relapsed encephalitis was seen in approximately 10% of those who survived the initial illness. Since its first recorded emergence in peninsular Malaysia, 10 outbreaks of Nipah virus encephalitis have been reported in Bangladesh and West Bengal in India. The outbreaks occurred from January to May, with Pteropus giganteus as the reservoir of the virus. In Bangladesh, evidence indicated that the virus transmitted directly from bats to human, with human to human transmission as an important mode of spread. The mortality of the illness was higher in Bangladesh which stood at around 70%. This was likely to be due to genetic variation of the virus.
  10. Chu, W.L., Phang, S.M., Lim, S.L., Teoh, M.L., Wong, C.Y.
    ASM Science Journal, 2009;3(2):178-183.
    MyJurnal
    Chlorella is one of the common microalgae found in a wide range of habitats, including Antarctica. Chlorella UMACC 234 is an interesting isolate in the collection of Antarctic microalgae in the University of Malaya algae culture collection (UMACC) as it grows well at temperatures much higher than the ambience. The alga was isolated from snow samples collected from Casey, Antarctica. This study investigates the influence of nitrogen source on the growth, biochemical composition and fatty acid profile of Chlorella UMACC 234. The cultures were grown in Bold’s Basal Medium with 3.0 mM NaNO3, NH4Cl or urea. The cultures grown on NaNO3 attained the highest specific growth rate (μ = 0.43 day–1) while the specific growth rates of those grown on NH4Cl and urea were not significantly different (p > 0.05). The urea-grown cells produced the highest amounts of lipids (25.7% dry weight) and proteins (52.5% dry weight) compared to those grown on other nitrogen sources. The cell numbers attained by the cultures grown at NaNO3 levels between 0.3 and 3.0 mM were similar but decreased markedly at 9.0 mM NaNO3. The fatty acids of Chlorella UMACC 234 were dominated by saturated fatty acids, especially 16:0 and 18:0. The percentage of polyunsaturated fatty acids was very low, especially in cells grown on urea (0.9% total fatty acids). Characterisation of the growth and biochemical composition of this Antarctic Chlorella is important to our studies on the relationship of Chorella isolates from tropical, temperate and polar regions, especially in terms of phylogeny and stress adaptation.
  11. Nur Ain, A.R., Mohd Sabri, M.G., Wan Rafizah, W.A., Nurul Azimah, M.A., Wan Nik, W.B.
    ASM Science Journal, 2018;11(101):56-67.
    MyJurnal
    Corrosion is a natural deterioration process that destructs metal surface. Metal of highly
    protected by passivation layer such as Stainless Steel 316L also undergoes pitting corrosion
    when continuously exposed to aggressive environment. To overcome this phenomenon, application
    of epoxy based coating with addition of zinc oxide- poly (3,4-ethylenedioxythiophene)
    doped with poly (styrene sulphonate) hybrid nanocomposite additive was introduced as
    paint/metal surface coating. The compatibility between these two materials as additive
    was studied by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD),
    Field Emission Scanning Electron Microscopy/Energy-Dispersive X-ray spectroscopy (FESEM/EDX)
    and Transmission Electron Microscopy (TEM) analysis. The effect of nanocomposite
    wt.% in epoxy based coating with immersion duration in real environment on corrosion
    protection performance was analyzed through potentiodynamic polarization analysis. The
    main finding showed that addition of hybrid nanocomposite had increased corrosion protection
    yet enhanced corrosion process when excess additives was loaded into epoxy coating.
    Addition of 2 wt.% ZnO-PEDOT:PSS was found significantly provided optimum corrosion
    protection to stainless steel 316L as the corrosion rate for 0 day, 15 days and 30 days of
    immersion duration is 0.0022 mm/yr, 0.0004 mm/yr and 0.0015 mm/yr; respectively.
  12. Monajemia, H., Daud, M.N., Zain, S.M., Wan Abdullah, W.A.T.
    ASM Science Journal, 2012;6(2):138-143.
    MyJurnal
    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.
  13. R. Abd-Shukor, W.Y. Lim
    ASM Science Journal, 2013;7(1):18-22.
    MyJurnal
    The electron-phonon coupling constant of the copper oxide-based high temperature superconductors in the van Hove scenario was calculated using three known models and by employing various acoustic data. Three expressions for the transition temperature from the models were used to calculate the constants. All three models assumed a logarithmic singularity in the density of states near the Fermi surface. The calculated electron-phonon coupling constant ranged from 0.06 to 0.28. The constants increased with the transition temperature indicating a strong correlation between electron-phonon coupling and superconductivity in these materials. These values were smaller than the values estimated for the conventional three-dimensional BCS theory. The results were compared with previous reports on direct measurements of electron-phonon coupling constants in the copper oxide based superconductors.
  14. Varatharajoo, R.
    ASM Science Journal, 2011;5(2):153-155.
    MyJurnal
    Malaysia has adopted various strategies in developing its space sector. Indigenous space technologies would enable a sustainable growth of the space field and at the same time develop the strategic space technologies. Therefore, issues related to the current space research level are fundamentally crucial to be highlighted. Subsequently, the space focus areas can be derived in order to meet the expectations of the national and international space technology growth requirements, which are moving on to a stronger posture in R&D. In the absence of a strong R&D national space industry leadership, the Malaysian space sector remains in a traditional downstream mode of the world space technology supply chain ever since. The space technology supply chain can be divided into the ground segment and the space segment. This paper examines the current space research activities in Malaysia within the framework of the space technology supply chain. As a result, a preliminary gap in the overview of space research in Malaysia is established.
  15. Neo, Han-Foon, Teo, Chuan-Chin, Ong, Thian Song, Devinaga Rasiah, Tong, David Yoon Kin
    ASM Science Journal, 2017;10(101):29-45.
    MyJurnal
    Brick-and-mortar business activities are gradually being replaced by e-commerce worldwide. The number
    of transactions and revenue should be correspondingly higher but due to the increase in the number of
    fraudulent cases, especially unauthorised use of credit cards, the record remains unbreakable. The use
    of biometrics is an optimal solution to safeguard the online user’s identity integrity. However, the best
    practicable way onimplementing biometrics with e-commerce is still in progress. The online user’s identity
    integrity is important because a secure transaction that increases user confidence will directly encourage
    more business. Motivated by the idea “Attack is the best form of defence”, hackers and imposters should
    be misled, traced and penalised accordingly in a proactive approach. In this paper, an intelligent stateof-the-art
    identity integrity safeguard framework encompassing fingerprint technology, a hiddenrisk
    analysis agent mechanism and real-time reporting is proposed. Since e-commerce is ubiquitous, it is
    possible to determine online users’ attitudes from different countries which enables collaboration with a
    French research unit. The findings would be significant to cyberlaw makers and e-commerce merchants
    to promote a secured e-commerce application from the online user’s perspective and consequently
    extend the findings to the m-commerce platform.
  16. Teh, G.B., Wong, Y.C., Tilley, R.D.
    ASM Science Journal, 2014;8(1):21-28.
    MyJurnal
    Co(II)-Ti(IV)-substituted magnetoplumbite-type (M-type) barium ferrite nanoparticles were synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. Structural and magnetic properties were characterised via X-ray diffraction (XRD), high resolution transmission electron microscopy and superconducting quantum interference device magnetometry. The particle sizes of the M-type BaCoXTiXFe12-2XO19 (0.2 ≤  ≤ 1.0) were found to be 900 Å – 1500 Å. The XRD results confirmed that the Co(II)-Ti(IV) substituted ferrites in the range of 0.2 ≤  ≤ 1.0 substitution had the M-type ferrite as the dominant phase. The hysteresis loss per-cycle decreased with increasing Co(II)-Ti(IV) substitution in M-type ferrites which showed reduced values in coercivity and remnant magnetisation with moderate effect on the saturation magnetisation.
  17. Abdul-Rashid, H.A., Al-Qdah, M.T., Chuah, H.T., Tayahi, M.
    ASM Science Journal, 2008;2(2):129-132.
    MyJurnal
    The operating principle and the performance of chromatic dispersion (CD) measurement technique are discussed through developed numerical models. The performance of the CD measurement technique was studied in terms of the measurement range and sensitivity as the wavelength separation was varied. Based on the numerical model, the technique sensitivity increased with wavelength separation. However, this increase in sensitivity was traded off with a narrower measurement range. The measurement technique was optimized at 5.0 GHz wavelength separation with a sensitivity of 0.009 (dB/ps/nm) and measurement range of 2500 ps/nm.
  18. Ng, W. L., Tan. S.G.
    ASM Science Journal, 2015;9(1):30-39.
    MyJurnal
    Inter-simple sequence repeats (ISSRs) are regions in the genome flanked by microsatellite sequences.
    PCR amplification of these regions using a single primer yields multiple amplification products that can
    be used as a dominant multilocus marker system for the study of genetic variation in various organisms.
    ISSR markers are easy to use, low-cost, and methodologically less demanding compared to other
    dominant markers, making it an ideal genetic marker for beginners and for organisms whose genetic
    information is lacking. Here, we comment upon some of the intricacies often overlooked in designing an
    ISSR experiment, clarify some misconceptions, and provide recommendations on using ISSR markers
    in genetic variation studies.
  19. Tan, S.L.
    ASM Science Journal, 2015;9(1):21-27.
    MyJurnal
    Public awareness and understanding of the technology behind the creation of Genetically Modified Organisms
    (GMOs) varies greatly from country to country, and indeed within the different sectors of any one country. Perhaps,
    it is “the fear of the unknown” at work, or it is just a pure rejection of the idea that “Man is playing God”. For whatever
    reason, and for whatever vested interest, there is often widespread clamor for stringent studies to be carried out
    when conducting a risk assessment of GMOs.
    For example, in Indonesia, regulation on the release of GMOs requires studies on any impact on non-target
    organisms (NTOs) as well as on soil microorganisms (Machmud Thohari 2014). Similarly, in Vietnam, it is mandatory
    to determine if there is any impact to the soil environment or ecosystem (Truong 2014), while in Cambodia, there is
    worry over high levels of damage to NTOs and the environment from GMOs, because of the lack of capacity to cope
    with such damage if it occurs (Pisey 2014).
    All too often, opponents of modern biotechnology (a term used to define technologies resulting in GMOs), and,
    indeed, the regulators themselves forget that there is already a procedure in place to provide a check and balance;
    the risk assessment (RA) protocol. Most times, RA is far more stringent when conducted on GMOs compared with
    when exotic species which are non-GMOs are involved (Tan 2013). It is also overlooked that modern biotechnology
    can after all be considered a sophisticated new tool in plant breeding, an activity which has been practiced both by
    farmers and scientists for millennia, and a technology accepted by all and sundry.
    While GMOs are currently used in biological and medical research, for the production of pharmaceutical drugs,
    in experimental medicine (e.g. gene therapy) and in agriculture, this paper is confined to discussions on GMOs in
    agriculture.
  20. Salleh, S., McMinn, A., Mohammad, M., Yasin, Z., Tan, S.H.A.
    ASM Science Journal, 2010;4(1):81-88.
    MyJurnal
    Elevated temperature affects marine benthic algae by reducing growth and limits the transport of electron or carbon fixation which may reduce the ability of the cell to use light. This resulting excess light energy may cause photoinhibition. In this study, the photosystem II of the benthic microalgal communities from Casey, eastern Antarctic were relatively unaffected by significant changes in temperatures up to 8ºC, along with high PAR level (450 μmol photons m–2 s–1). Similarly, the community was able to photosynthesize as the temperature was reduced to –5ºC. Recovery from saturating and photoinhibiting irradiances was not significantly influenced by temperatures at both –5ºC and 8ºC. These responses were consistent with those recorded by past experiments on Antarctic benthic diatoms and temperate diatoms which showed that climate change did not have a significant impact on the ability of benthic microalgae to recover from photoinhibitory temperature stress.
Filters
Contact Us

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

External Links