Displaying publications 41 - 60 of 95 in total

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  1. Salmah Moosa, Seri Chempaka Mohd. Yusof, Ruzalina Bahrin, Maizatul Akmam Md. Nasir
    MyJurnal
    Radiation processing of food materials by gamma-radiation is a well-established method for
    microbial decontamination and insect disinfestation. Irradiation of spices at doses ranging from
    10 to 30 kGy has been reported to result in complete elimination of microorganisms with
    negligible changes in the flavour quality. The effect of gamma-radiation on microflora and
    vanillin content of cured vanilla beans in the dose range of 5 - 50 kGy has been investigated, but
    its effect on other major aroma compounds and vanillin glucoside (vanillin aroma precursor)
    remaining after curing have not been studied so far. Vanillin (4-hydroxy-3-methoxybenzaldehyde)
    is one such compound used as a flavouring agent and as a dietary component. It is the major
    component of natural vanilla, which is one of the most widely used and important flavouring
    materials throughout the world. Vanillin is an antioxidant capable of protecting membrane
    against lipid peroxidation and DNA against strand breaks induced by reactive oxygen species.
    The present work was aimed to study the effect of gamma-radiation processing on the major
    aroma compounds of cured vanilla beans and also to investigate possible enhancement in vanillin
    content by the radiolytic breakdown of vanillin glucoside present already. Cured vanilla beans
    were irradiated (5, 10, 15, 20 and 30 kGy) and the vanillin content of control and irradiated
    samples were analysed, respectively for possible enhancement of vanillin content by radiolysis of
    vanillin glucoside. Radiolytic breakdown of glycosidic precursors of aroma constituents and
    consequent release of free aroma was shown to result in the enhancement of aroma quality of
    these products. Since a considerable amount of vanillin exists as its glycosidic precursor in cured
    vanilla pods, a possible enhancement in yield of vanillin by radiation processing is thus expected.
    Hence the highly stable oxygen–carbon linkage between vanillin and glucose limits the possible
    enhancement of aroma quality of irradiated beans.
  2. Lombigit, Lojius, Maslina Ibrahim, Nolida Yusup, Nur Aira Abdul Rahman, Yong, Chong Fong
    MyJurnal
    Pulse Shaping Amplifier (PSA) is an essential component in nuclear spectroscopy system. This
    amplifier has two functions; to shape the output pulse and performs noise filtering. In this paper,
    we describe the procedure for the design and development of a pulse shaping amplifier which can
    be used in a nuclear spectroscopy system. This prototype was developed using high performance
    electronics devices and assembled on a FR4 type printed circuit board. Performance of this
    prototype was tested by comparing it with an equivalent commercial spectroscopy amplifier (Model
    Silena 7611). The test results showed that the performance of this prototype was comparable
    to the commercial spectroscopic amplifier.
  3. Nur Humaira’ Lau Abdullah, Zal U’yun Wan Mahmood, Norfaizal Mohamed @ Muhamad, Nazaratul Ashifa Abdullah Salim, Ahmad Nazrul Abd Wahid, Nor Dalila Desa, et al.
    MyJurnal
    A glasshouse experiment was performed to evaluate the uptake of grasses viz. Napier and Vetiver
    in radiophytoremediation of caesium-contaminated soil. The radiophytoremediation experiment
    was designed according to the Randomized Complete Block Design (RCBD). The grasses were
    grown in troughs filled with soil mixed with a known specific activity of 134Cs. Initial Cs activity and
    activity after different cultivation time intervals of 1, 3, 6 and 9 months were analyzed using gamma
    spectrometer direct measurement. The results showed the uptake of caesium by Napier and Vetiver
    after 9 months with the transfer factors (TF) were 4.70 and 6.25, respectively. The remediation of
    caesium from the contaminated soil during the study period was 98.08% for Napier and 98.21% for
    Vetiver. Both grasses have been found to accumulate caesium, with Vetiver accumulating higher
    than Napier. Thus, the present study suggests that Vetiver could be used as a potential plant for
    radiophytoremediation of caesium.
  4. Ros Anita Ahmad Ramli, Ahmad Zainuri Mohd Dzomir, Zainon Othman, Wan Saffiey Wan Abdullah, Muhamad Samudi Yasir
    MyJurnal
    The exposure of food to ionizing radiation is being progressively used in many countries to
    inactivate food pathogens, to eradicate pests and to extend shelf-life of food. To ensure free
    consumer choice, irradiated food will be labeled. The availability of a reliable method to detect
    irradiated food is important to enforce legal controls on labeling requirements, ensure proper
    distribution and increase consumer confidence. This paper reports on the preliminary application
    of photostimulated luminescence technique (PSL) as a potential method to detect irradiated food
    and perhaps be used for monitoring irradiated food on sale locally in the near future. Thus this
    study will be beneficial and relevant for application of food irradiation towards improving food
    safety and security in Malaysia.
  5. Mohd Fauzi Haris, Saaidi Ismail, Mohamad Safuan Sulaiman, Mohd Dzul Aiman Aslan, Siti Nurbahyah Hamdan, Maslina Mohd Ibrahim, et al.
    MyJurnal
    The remote measurements of radiation level at an identified location, are not only important for
    collecting data or monitoring radiation level per se, but also crucial for workers who deal with
    radiation sources. A device for checking an on-site radiation level has been developed quite a
    long time ago under the name of Geiger Muller and widely known as a Geiger counter. The
    reading of the output can be seen on the device on-site and on real-time basis. Nowadays, with
    the fast evolution of computer and networking technology, those reading not only can be read
    real-time but also from a remote location that makes workers able to enter the risky area more
    safely. The collected data reading also can be analyzed for predicting the future trending
    pattern. The data is transferred from the monitoring devices to a server through a network. This
    paper discusses about several critical issues on the design, implementation and deployment that
    relates to the devices, interface programs, hardware and software that allow all parameters such
    as radiation levels reading and the timestamp of the data-logging can be collected and stored in
    a central storage for further processes. The compatibility issue with regards to technology
    change from the previous system will also be discussed. The system has many advantages
    compared to previous system and conventional method of doing the area monitoring in term of
    sustainability and availability.
  6. Aida Nazlyn Nazari, Azhar Mohamad, Shuhaimi Shamsudin
    MyJurnal
    Assessing performance and genetic diversity of the wild material of oil palm is important for
    under- standing genetic structure of natural oil palm populations towards improvement of the
    crops. This in-formation is important for oil palm breeding programs, and also for continued exsitu
    conservation of the germplasm and breeding program in Malaysia. Mutation induction is one
    of the approaches in creating variants for selection in the breeding program. In this study, the
    effect of irradiated pollen towards pollen viability, bunches formation and number of
    parthenocarpic fruits were evaluated. Elaies guineensis Jacq. pollens were exposed to series of
    acute gamma radiation at dose 0, 10, 20, 40, 50, 100, 200, 300, 500, 100 and 2000 Gy . Pollen
    viability and pollen tube formation were disrupted in which unable the pollen to reach the ovule.
    At this stage, embryo was aborted towards formation of parthenocarpic fruits and rotten bunches.
    The study suggested that at low levels of irradiation i.e. < 200 Gy, generative nucleus partially
    damage and it is still maintaining capacity of fertilizing the egg cells for hybridization. It is
    important for breeders in understanding this finding towards novel variants of oil palm via
    mutation induction
  7. Muhamat Omar, Zalina Laili, Abd Khalik Wood, Julia Abdul Karim, Zarina Masood, Mohd Fazli Zakaria, et al.
    MyJurnal
    A systematic study to assess the concentration of radionuclides in primary coolant and associated water samples from the operation of a TRIGA Mark II reactor has been carried out. The samples were transferred into appropriate counting container and were counted by efficiency-calibrated gamma spectrometer systems for several hours to obtain statistically adequate data for qualitative and quantitative evaluation of the radioactive materials presence. The primary coolant was found to contain various gamma emitting radionuclides including 24Na, 41Ar, 42K, 51Cr, , 54Mn, 56Mn, 60Co, 99mTc, 122Sb, 124Sb and 187W. Most of the detected radionuclides were inferred to be originated from activation products of (n,) nuclear reactions of elements of reactor components such as stainless steel and aluminium alloy used in the reactor system. The study confirms the integrity of the reactor system with no apparent release of any fission products radionuclide into the coolant water system.
  8. Rosli Darmawan
    MyJurnal
    The study on the possibility of using DMU Kinematics module in CAE tools for dose exposure work planning was carried out. A case scenario was created using 3D CAD software and transferred to DMU Kinematics module in a CAE software. The work plan created using DMU Kinematics module was animated to simulate a real time scenario. Data on the phantom position against the radioactive source was collected by activating positioning sensors in the module. The data collected was used to calculate the estimated dose rate exposure for the phantom. The results can be used to plan the safest and optimum procedures in carrying out the radiation related task.
  9. Zal U’yun Wan Mahmood, Zaharudin Ahmad, Che Abd Rahim Mohamed, Abdul Kadir Ishak, Norfaizal Mohammed
    MyJurnal
    The distribution, enrichment and pollution status of metals in sediment cores from the Sabah-Sarawak coastal waters were studied. Seven sediment cores were taken in July 2004 using a gravity box corer. The metals of Cu, Zn and Pb were analyzed by ICP-MS to assess the pollution status of the sediments. The sediment fine fraction and organic carbon content was also analyzed. Enrichment Factor (EF), Geoaccumulation Index (Igeo) and Pollution Load Index (PLI) was calculated as criteria of possible contamination. The results showed that collected sediments were composed with clay, silt and sand as 12 – 74%, 27 – 72% and 0 – 20%, respectively. Meanwhile, organic carbon contents were relatively low and constant over time, based on sediment depth profiles, and it did not exceed 5% at any sampling station. The average metal concentrations in sediment cores at all sampling station were distributed in the ranges of 1.66 ± 1.36 – 6.61 ± 0.12 μgg-1 for Cu, 26.55 ± 1.04 – 57.94 ± 1.58 μgg-1 for Zn and 3.99 ± 0.10 – 14.48 ± 0.32μgg-1 for Pb. According to calculations of EF, Igeo and PLI, it can be concluded that concentrations of Cu, Zn and Pb were not significantly affected by pollution from anthropogenic sources at the seven sampling locations. Thus, the metal content of Cu, Zn and Pb in sediment should not cause pollution problem to the marine environment of Sabah-Sarawak coastal waters and further response measures are not needed.
  10. Mohd Azmi Ismail, Mohammad Roston Zakaria
    MyJurnal
    An appraisal of the regional reconnaissance geophysical, geochemical and geological data obtained under the Central Belt Project in 1977 – 1978 appeared to constitute favourable uranium exploration targets. Follow-up surveys conducted until the year 1990 have proposed the exploration area to be divided into three transects. Transect 1 covers the western part of the state of Kelantan, northwest Pahang and the eastern half of Perak. Transect 2 covers southeastern tip of Perak, west Pahang, eastern half of Wilayah Persekutuan, eastern portion of Selangor, and the northwest portion of Negeri Sembilan. Transect 3 covers central Kelantan, northwestern of Terengganu and northern portion of Pahang. Results of the study indicate that the Main Range, Bujang Melaka, and Bukit Tinggi Plutons are most fertile with uranium spectrometric rock values range from 13 to 25 ppm. Further investigations to zero down the target areas for uranium mineralization are strongly recommended over these areas.
  11. Mohd Amirul Syafiq Mohd Yunos, Zainal Abidin Talib, Wan Mahmood Mat Yunus, Liew, Josephine Ying Chyi, Paulus, Wilfred Sylvester
    MyJurnal
    Semiconductor thin films Copper Tin Selenide, Cu2SnSe3, a potential compound for solar cell applications or semiconductor radiation detector were prepared by thermal evaporation method onto well-cleaned glass substrates. The as-deposited films were annealed in flowing purified nitrogen N2, for 2 hours in a temperature range from 100˚C to 500˚C. The structure of as-deposited and annealed films has been studied by X-ray diffraction technique. The semi-quantitative analysis indicated from Reitveld refinement show that the samples composed of Cu2SnSe3 and SnSe. These studies revealed that the films were structured in mixed phase between cubic space group F-43m (no. 216) and orthorhombic space group P n m a (no. 62). The crystallite size and lattice strain were determined from Scherrer calculation method. The results show that increasing in annealing temperature resulted in direct increase in crystallite size and decrease in lattice strain.
  12. Muhammad Rawi Mohamed Zin, Mahendrasingam, Arumugam, Konkel, Chris, Narayanan, Theyencheri
    MyJurnal
    Changes in molecular structure configuration during strain induced crystallisation of an amorphous Poly(Lactic Acid) (PLA 4032D) polymer was monitored in-situ by simultaneously recording the wide angle x-ray scattering (WAXS) and small angle x-ray scattering (SAXS) patterns together with polymer deformation images and force data. The amorphous chain orientation from the beginning of deformation until the onset of crystallisation was studied from the WAXS patterns. The true mechanical behaviour described by the true stress-true strain curve related to an amorphous chain orientation exhibited a linear behaviour. Approaching critical amorphous orientation, the true stress-true strain curve deviated from linear into non-linear behaviour. After the onset of crystallization, when the deformed polymer became a semicrystalline state, the true mechanical behaviour exhibited true strain hardening which greatly affected by the formation of the morphology. The gradual true strain hardening was associated with the formation of micro-fibrillar structure containing thin crystallite morphology whilst sharp increased in true strain hardening was associated with the formation of stacked lamellar morphology in the form of macro-lattice structure. The study was accomplished by the application of high brilliance synchrotron radiation at beamline ID2 of ESRF, Grenoble in France and the usage of the high contrast resolution of WAXS and SAXS charge-couple device (CCD) camera as well as 40 milliseconds temporal resolution of data acquisition system.
  13. Norpaiza Mohamad Hasan, Noraini Haron, Mohamad, Glam Hadzir Patai, Ismail Mustapha, Syed Yusainee Syed Yahya
    MyJurnal
    Paper recycling plants usually buy their raw material from suppliers. More than often, bulk used paper supplied to the plant contains some significant quantity of water in its internal voids. It may be included intentionally or unintentionally. The price of used paper depends on its weight, thus adding water will help to increase weight and consequently increase the price. In this way, plant owner who purchase the used paper suffers a significant of financial lost. The objectives of our experiment are to establish a calibration curve that correlate between the amount of neutron backscattered and water content, and finally to develop a correction factor that need to be introduced to the measured values of water content. A fast neutron source (Am-Be 241) and a portable backscattering neutron detector were used for water measurement. The experiments were carried out by measuring neutron backscattering from used paper that has been added with different amount of water. As a result, a neutron calibration curve that provides a correlation between neutron backscattering and water content was established.
  14. Selambakkannu, Sarala, Bakar, Khomsaton Abu, Ming, Ting Teo, Jamaliah Sharif
    MyJurnal
    In this studies gamma and electron beam irradiation was used to treat textile waste water. Comparisons between both types of irradiation in terms of effectiveness to degrade the pollutants present in textile waste water were done. Prior to irradiation, the raw wastewater was diluted using distilled water to a target concentration of COD 400 mg/l. The sample was irradiated at selected doses between the ranges of 10 kGy to 100 kGy. The results showed that irradiation has significantly contributed in the reduction of the highly colored refractory organic pollutants. The COD removal at the lowest dose, 10 kGy was reduced to 390 mg/l for gamma and 400 mg/l for electron beam. Meanwhile, at the highest dose, 100 kGy, the COD was reduced to 125 mg/l for gamma and 144 mg/l for electron beam. The degree of removal is influenced by the dose introduced during the treatment process. As the dose increased, the higher the removal of organic pollutant was recorded. However, gamma irradiation is more effective although the differences are not significant between gamma and electron beam irradiation. On the other hand, other properties of the wastewater such as pH, turbidity, suspended solid, BOD and color also shows a gradual decrease as the dose increases for both types of irradiation.
  15. Muhamat Omar, Zalina Laili, Mohd Suhaimi Hamzah
    MyJurnal
    Qualitative and quantitative analysis of samples require good judgment from the analysts. These two aspects in gamma spectrometric analysis of Proficiency Test and solid radioactive waste samples for the determination of radionuclides are discussed. It is vital to judge and decide what energy peaks belong to which radionuclides prior to the creation of customized radionuclide library for the analysis of specific samples. Corrections due to radionuclide decay and growth, and the half-life assigned to a particular radionuclide in the uranium and thorium series are also discussed. Discussion on judgment to confirm the presence of thorium in food samples based on gamma spectrometry and neutron activation analysis is also provided.
  16. Nolida Yussup, Nur Aira Abd. Rahman, Ismail Mustapha, Jaafar Abdullah, Mohd. Ashhar Khalid, Hearie Hassan, et al.
    MyJurnal
    Data transmission in field works especially that is related to industry, gas and chemical is paramount importance to ensure data accuracy and delivery time. A development of wireless detector system for remote data acquisition to be applied in conducting fieldwork in industry is described in this paper. A wireless communication which is applied in the project development is a viable and cost-effective method of transmitting data from the detector to the laptop on the site to facilitate data storage and analysis automatically, which can be used in various applications such as column scanning. The project involves hardware design for the detector and electronics parts besides programming for control board and user interface. A prototype of a wireless gamma scintillation detector is developed with capabilities of transmitting data to computer via radio frequency (RF) and recording the data within the 433MHz band at baud rate of 19200.
  17. Md Fakarudin Ab Rahman, M. Iqbal Saripan, Nor Pa’iza Mohamad Hasan, Ismail Mustapha
    MyJurnal
    The total mass attenuation coefficients (μ/ρ) of stainless steel (SS316L) and carbon steel (A516) that are widely used as petrochemical plant components, such as distillation column, heat exchanger, boiler and storage tank were measured at 662, 1073 and 1332 keV of photon energies. Measurements of radiation intensity for various thicknesses of steel were made by using transmission method. The γ-ray intensity were counted by using a Gamma spectrometer that contains a Hyper-pure Germanium (HPGe) detector connected with Multi Channel Analyzer (MCA). The effective numbers of atomic (Zeff) and electron (Neff) obtained experimentally were compared by those obtained through theoretical calculation. Both experimental and calculated values of Zeff and Neff were in good agreement.
  18. Zaidi Embong
    MyJurnal
    This review briefly describes some of the techniques available for analysing surfaces and illustrates their usefulness with a few examples such as a metal and alloy. In particular, Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and laser Raman spectroscopy are all described as advanced surface analytical techniques. In analysing a surface, AES and XPS would normally be considered first, with AES being applied where high spatial resolution is required and XPS where chemical state information is needed. Laser Raman spectroscopy is useful for determining molecular bonding. A combination of XPS, AES and Laser Raman spectroscopy can give quantitative analysis from the top few atomic layers with a lateral spatial resolution of
  19. Phillip, Esther, Muhamad SamudiYasir, Muhamat Omar, Mohd Zaidi Ibrahim, Zalina Laili
    MyJurnal
    Effect of washing solutions’ pH on removal of radium-226 from radium-contaminated soil using distilled water and humic acid extracted from Malaysian peat soil was studied by a single batch washing method. The study encompassed the extraction of humic acid and the washing of radium-contaminated soil using distilled water and humic acid solutions of varying pH in the range between 3 to 11. Activity of radium-226 was determined by gamma spectrometer. In the pH range studied, the removal of radium-226 was greater when humic acid solutions were used compared to distilled water. Greater removal of radium-226 was obtained using highly basic pH washing solutions compared to neutral and acidic solutions.
  20. Mohamad Hairie Rabir, Julia Abdul Karim, Mohd Amin Sharifuldin Salleh
    MyJurnal
    The Malaysian 1 MW TRIGA MARK II research reactor at Malaysian Nuclear Agency is designed to effectively implement the various fields of basic nuclear research, manpower training, and production of radioisotopes for their use in agriculture, industry, and medicine. This study deals with the calculation of neutron flux and power distribution in PUSPATI TRIGA REACTOR (RTP) 14th core configuration. The 3-D continuous energy Monte Carlo code MCNP was used to develop a versatile and accurate full model of the TRIGA core and fuels. The model represents in detailed all components of the core with literally no physical approximation. Continuous energy cross-section data from the more recent nuclear data as well as S (α, β) thermal neutron scattering functions distributed with the MCNP code were used. Results of calculations are analyzed and discussed.
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