Displaying publications 1 - 20 of 95 in total

  1. Nolida Yussup, Nur Aira Abd. Rahman, Ismail Mustapha, Jaafar Abdullah, Mohd. Ashhar Khalid, Hearie Hassan, et al.
    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.
  2. Radaideh, K.M., Matalqah, L.M., Tajuddin, A.A., Lee Luen, F.W., Bauk, S., Abdel Munem, E.M.E
    The ultimate check of the actual dose delivered to a patient in radiotherapy can be achieved by using dosimetric measurements. The aims of this study were to develop and evaluate a custom handmade head and neck phantom for evaluation of Three-Dimensional Conformal Radiation Therapy (3D-CRT) dose planning and delivery. A phantom of head and neck region of a medium built male patient with nasopharyngeal cancer was constructed from Perspex material. Primary and secondary Planning Target Volume (PTV) and twelve Organs at Risk (OAR) were delineated using Treatment Planning System (TPS) guided by computed tomography printout transverse images. One hundred and seven (107) holes distributed among the organs were loaded with Rod-shaped Thermoluminescent dosimeters (LiF:Mg,Ti TLDs) after common and individual calibration. Head and neck phantom was imaged, planned and irradiated conformally (3D-CRT) by linear accelerator (LINAC Siemens Artiste). The planned predicted doses by TPS at PTV and OAR regions were obtained and compared with the TLD measured doses using the phantom. Repeated TLD measurements were reproducible with a percent standard deviation of < 3.5%. Moreover, the average of dose discrepancies between TLDs reading and TPS predicted doses were found to be < 5.3%. The phantom’s preliminary results have proved to be a valuable tool for 3D-CRT treatment dose verification.
  3. Siong, Wee Boon, Ebihara, Mitsuru
    Prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA) are essential for the study of rare samples such as meteorites because of non-destructivity and relatively being free from contaminations. The objective of this research is to utilize PGA and INAA techniques for comparative study and apply them to meteorite analyses. In this study, 11 meteorite samples received from the Meteorite Working Group of NASA were analyzed. The Allende meteorite powder was included as quality control material. Results from PGA and INAA for Allende showed in good agreement with literature values, signifying the reliabilities of these two methods. Elements Al, Ca, Mg, Mn, Na and Ti were determined by both methods and their results are compared. Comparison of PGA and INAA data using linear regression analysis showed correlations coefficients r2 > 0.90 for Al, Ca, Mn and Ti, 0.85 for Mg, and 0.38 for Na. The PGA results for Na using 472 keV were less accurate due to the interference from the broad B peak. Therefore, Na results from INAA method are preferred. For other elements (Al, Ca, Mg, Mn and Ti), PGA and INAA results can be used as cross-reference for consistency. The PGA and INAA techniques have been applied to meteorite samples and results are comparable to literature values compiled from previously analyzed meteorites. In summary, both PGA and INAA methods give reasonably good agreement and are indispensable in the study of meteorites.
  4. Zal U’yun Wan Mahmood, Zaharudin Ahmad, Che Abd Rahim Mohamed, Abdul Kadir Ishak, Norfaizal Mohammed
    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.
  5. Sakinah Ariffin, Azhar Mohamad, Ratnam, Wickneswari
    Jurnal Sains Nuklear Malaysia, 2012;24(1):91-101.
    Colour is one of the most important traits in orchids and has created great interest in breeding programmes. Gamma irradiation is an alternative way for generation of somaclonal variation for new flower colours. Phenotypic changes are usually observed during screening and selection of mutants. Understanding of targeted gene expression level and evaluation of the changes facilitate in the development of functional markers for selection of desired flower colour mutants. Four Dendrobium orchid sequences (NCBI accessions: AM490639, AY41319, FM209429 and DQ462460) were selected to design gene specific primers based on information for chalcone synthase (CHS) from NCBI database. Quantitative real-time PCR (qPCR) was used to understand flower colour expression quantitatively derived from the CHS gene activities in different flower tissues (petal and sepal) from control Dendrobium Sonia (red purple), mutant DS 35-1/M (purple pink) and mutant DS 35-WhiteA. It was found that expression of CHS gene was highest in sepals of white flowers and lowest in both sepals and petals of purple pink flowers. Genomic DNA was amplified and PCR products were sequenced, aligned and compared. Sequence variations of CHS partial gene in Dendrobium Sonia mutants with different flower colour showed that two protein positions have been changed as compared to the control. These non-synonymous mutations may have contributed to the colour alterations in the white and purple pink mutants. This paper describes important procedures to quantify gene expression such as RNA isolation (quantity and quality), cDNA synthesis and primer design steps for CHS genes.
  6. Mei-Wo, Yii, Kamarozaman Ishak, Nooruzainah Abu Hassan, Maziah Mahmud, Khairul Nizam Razali
    Jurnal Sains Nuklear Malaysia, 2012;24(1):102-112.
    IAEA Soil-6 is a reference material with a certified value for 226Ra fall between 69.6 – 93.4 Bq/kg at 95% confidence level. This material has been used as a sample and performed repeat measurement weekly between years 2006 – 2009 using a same gamma spectrometry system. The activity concentration of this material is calculated automatically using the operational commercial software and compared with activity obtained from the manual calculation. Study found that only 76.9%, 64.1%, 56.3%, and 79.3% of the results from the software calculation lie within the confidence level for year 2006, 2007, 2008 and 2009, respectively. However, u-score calculation revealed that 94.9 %, 89.7%, 79.2% and 84.9% data set have no significant bias (u < 2.58) for year 2006, 2007, 2008 and 2009, respectively. On the other hand, all manual calculation data were found to be within the 95 % confidence level. Factors suspected to cause differences between these two approaches were discussed here. Manually peak search, marking and calculation still remains as the preferred option for calculating the gamma radionuclides activity unless limitations of the spectrum analysis software, as described in this paper can be resolved/improved upon.
  7. Mohd Azmi Ismail, Mohammad Roston Zakaria
    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.
  8. Phillip, Esther, Muhamad SamudiYasir, Muhamat Omar, Mohd Zaidi Ibrahim, Zalina Laili
    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.
  9. Yusof Abdullah, Mohd Reusmaazran Yusof, Nadira Kamarudin, Paulus, Wilfred Sylvester, Rusnah Mustaffa, Nurazila Mat Zali, et al.
    Al/B4C composites with 0 wt.%, 5 wt.% and 10 wt.% of B4C were prepared by powder metallurgy and their properties were characterised successfully. Investigation of the effect of milling times (4, 8, 12, 16 hours) on microstructure, phase identification, hardness and neutron attenuation coefficient of composites has been studied. The results showed that hardness increased with increased of milling time, with maximum hardness obtained at 16 hours milling time. The increment is slower as the composition of B4C increased. The hardness of Al/10%B4C, Al/5%B4C and Al/0%B4C were 81.7, 78.7 and 61.2 HRB respectively. Morphology of scanning electron microscopy (SEM) showed that microstructures play important role in controlling the hardness. Meanwhile, x-ray diffraction (XRD) analysis showed the phases and crystalline present in composites with an indication that crystalline of the grain increased as the milling time increased. Neutron absorption of Al/10%B4C composites showed that this composite has the highest attenuation coefficient, thus indicating that it is the best composites for neutron shielding.
  10. Mohd Reusmaazran Yusof, Yusof Abdullah
    Nuclear grade (high-purity) graphite for fuel element and moderator material in Advanced Gas
    Cooling Reactors (AGR) displays large scatter in strength and a non-linear stress-strain response from the damage accumulation. These responses can be characterized as quasi-brittle behaviour. Current assessments of fracture in core graphite components are based on the linear elastic approximation and thus represent a major assumption. The quasi-brittle behaviour gives challenge to assess the real nuclear graphite component. The selected test method would help to bridge the gap between microscale to macro-scale in real reactor component. The small scale tests presented here can contribute some statistical data to manifests the failure in real component. The evaluation and choice of different solution design of biaxial test will be discussed in this paper. The ball on-three ball test method was used for assessment test follows by numerous of analytical method. The results shown that biaxial strength of the EY9 grade graphite depends on the method used for evaluation. Some of the analytical methods use to calculate biaxial strength were found not to be valid and therefore should not be used to assess the mechanical properties of nuclear graphite.
  11. Fatema Anuar, Mohammed Iqbal Shueb, Ruzitah Mohd Salleh, Nazaratul Ashifa Abdullah Salim, Julia Abdul Karim
    Mechanical properties of blended polyethylene (PE) containing the antioxidant Irganox 1010 and the UV-absorber Tinuvin 326 were studied for future use as radiation capsule material for the TRIGA Mark II research reactor. High density and low density polyethylene were blended with the additives and tested for elongation at break, impact strength and gel content, before and after irradiation inside the nuclear reactor. Characterization via FTIR as well as determination of crystallization and melt transition temperatures through DSC were also conducted. It was found that the addition of the antioxidant at different amounts (from 0 to 4 phr) had various effects on the properties of the blended PE, with 0 phr being the amount at which there was the biggest increase in elongation at break and impact strength, post-irradiation.
  12. Muhamat Omar, Zalina Laili, Julia Abdul Karim, Zarina Masood, Nik Marzukee Nik Ibrahim, Mohd Abd Wahab Yusof
    A study to assess the concentration of radionuclides in spent resins of the PUSPATI TRIGA Mark II reactor coolant purification system has been carried out. Fresh spent resins collected and analysed in May 2010, after the changing of leaked heat exchanger in Sept. 2009 was found to contain 24Na, 122Sb, 51Cr, 124Sb, 58Co, 65Zn, 54Mn and 60Co. Old spent resins removed in 2001 and 2002 but analysed in 2010 indicated the presence of 60Co and 152Eu as radionuclides with half-lives of < 1 year might have already been decayed out. These results can be used to establish radionuclide inventory of the spent resins as part of radiation protection programme.
  13. Norpaiza Mohamad Hasan, Noraini Haron, Mohamad, Glam Hadzir Patai, Ismail Mustapha, Syed Yusainee Syed Yahya
    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
    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. Mohamad Hairie Rabir, Julia Abdul Karim, Mohd Amin Sharifuldin Salleh
    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.
  16. Muhamat Omar, Zalina Laili, Mohd Suhaimi Hamzah
    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.
  17. Md Suhaimi Elias, Mohd Suhaimi Hamzah, Mohd Suhaimi Hamzah, Siong, Wee Boon, Nazaratul Ashifa Abdullah Salim
    Assessment of source and sediment quality was carried out on marine sediments collected from the Tuanku Abdul Rahman National Park. Enrichment factors (EF), pollution load index (PLI) and geo-accumulation index (Igeo) were used to identify the sources of pollution, degree of contamination and sediment quality, respectively. Elemental analyses of marine sediment samples were performed by using the Instrumental Neutron Activation Analysis (INAA). Results from the Tunku Abdul Rahman National Park of Sabah indicated that most of the elements are considered to be from lithological or natural origin with EF values of less than 2 except for As (10 stations), Cr (3 stations), Lu (5 stations), Mg (2 stations), Sb (6 stations) and U (3 stations). For the sediment quality, most of the study area can be categorised as unpolluted for most of the elements (Igeo value < 2) except for As, Cr, Lu, Mg, Sb and U. A few study areas were slightly low contaminated with As, Cr, Lu, Mg, Sb and U. The contamination of As, Cr, Lu, Mg, Sb and U in the study area can be categorised as moderate with Igeo values ranged from 1 to 2. Meanwhile, the results of PLI value for sediment were ranged from 0.93 to 1.47 (PLI < 50) indicating there are not required to perform drastic rectification measures for the screening of the elements in the Tunku Abdul Rahman Park. Overall, assessment of the sediment quality at the Tunku Abdul Rahman National Park showed a few elements such as As, Cr, Lu, Mg, Sb and U were slightly enriched while most of the elements were similar to background values.
  18. Md Fakarudin Ab Rahman, M. Iqbal Saripan, Nor Pa’iza Mohamad Hasan, Ismail Mustapha
    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.
  19. Zaidi Embong
    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
  20. Muhamat Omar, Zalina Laili, Abd Khalik Wood, Julia Abdul Karim, Zarina Masood, Mohd Fazli Zakaria, et al.
    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.
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