Displaying publications 1 - 20 of 209 in total

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  1. Che Abd Rahim Mohamed, Tee, Lee Theng, Zaharuddin Ahmad
    MyJurnal
    Natural radionuclides such as 210 Po and 210 Pb were analyzed in soft part of cockle (Anadara granosa) obtained from Kuala Selangor in the west coast Peninsular of Malaysia. The activity levels of both nuclides fluctuated within the size of cockles from 41.3 ± 2.5 Bq/kg to 114 ± 7 Bq/kg and 12.9 ± 1.7 Bq/kg to 96.8 ± 5.3 Bq/kg in dry weight (dwt) for 210 Po and 210 Pb, respectively. The level activity in wet weight (wwt) also varied from 8.60 ± 0.52 Bq/kg to 25.70 ± 1.63 Bq/kg and 2.47 ± 0.40 Bq/kg to 19.27 ± 1.05 Bq/kg for 210 Po and 210 Pb, respectively, probably related to the different of metabolic rate and growth of cockles. Activity ratio of 210 Po/ 210 Pb in dry weight also fluctuated from 0.93 to 6.41 with not related to the decay of 210 Pb.
  2. Nioo, Siew Yew, Zaharuddin Ahmad, Masni Mohd Ali, Che Abd Rahim Mohamed
    MyJurnal
    Analyses activities of 226 Ra and 228 Ra were conducted at ten stations of Pulau Redang, Malaysia. Dissolved radium isotopes such as 226 Ra and 228 Ra had shown enrichment at coastal area stations. Meanwhile, activities of both nuclides in the suspended particle matters were slightly in equilibrium with the activity ratio ranging from 0.88 – 1.86. The calculated distribution coefficient values (Kd) of 226 Ra and 228 Ra were in the range of 0.78 x 10 5 L g -1 to 5.56 x 10 5 L g -1 and 0.21 x 10 5 L g -1 to 1.86 x 10 5 L g -1 , respectively, indicate that most of the radium nuclides in the study area are strongly absorbed into the particulate phases. Therefore, low concentrations of suspended particles matter in the water column (< 10 mg L -1 ) have insignificant effects on the Kd values.
  3. Noriah Jamal, Bo, Nelly Nai Lee, Rahimah Abdul Rahim, Noraisyah Yusof, Yahaya Talib, Hasmadi Hassan, et al.
    MyJurnal
    The blooming use of ionizing radiation in industry, research, agriculture, medicine and nuclear industry increases the risk of overexposure for radiation workers as well as members of the public. Ionizing radiation is a strong clastogen, causing chromosome breakage, and resulting in cytogenetic aberrations in exposed cells. Cytogenetic analysis of human blood lymphocytes has been widely used as the biological technique for quantifying radiation dose in man. In the investigation of radiation accident, it is important to estimate the dose absorbed by the exposed person in order for the attending medical doctor to plan for their therapy. This paper reviews the current status on cytogenetic biodosimetry methods for radiation dose assessment.
  4. Noraziana Parimin, Linus, Andy
    MyJurnal
    This research was conducted to study the effect of reinforcement particles on iron-cobalt (FeCo) composites. The composition of silicon carbide (SiC) was varied from 0 to 20 wt%. The composite was fabricated via powder metallurgy (PM) method, which consists of mixing, compaction and sintering processes. The powder was mixed for 2 hours to obtain uniformity between SiC and Fe-Co matrix and compacted to a cylindrical shape at 250 MPa. Samples were sintered for 2 hours at 900 o C with 10 o C/minute heating rate in argon atmosphere. The influences of reinforcement particle on the sintered samples were characterized in terms of microstructure and hardness testing. The Fe-Co/20wt%SiC composites show highest hardness value.
  5. Muhammad Fakhrurazi Ahmad Fadzil, Siti Selina Abdul Hamid, Siti Najila Mohd Janib, Azahari Kasbollah, Syed Asraf Fahlawi Wafa
    MyJurnal
    Medical radioisotope is a small quantity of radioactive substance used in safe, cost effective, for the
    purpose of diagnostic and therapy of various diseases. In Malaysia, the emerging of new nuclear
    medicine centers or institutions in both government and private sectors rose abruptly for the past few
    years. Currently, there are no data available on the usage and demand of medial radioisotope or
    radiopharmaceuticals. Understanding the usage trending and demand of radiopharmaceuticals and
    medical radioisotope is essential when related to technology changes in order to meet the market size
    of these radiopharmaceuticals. Survey result found out that the highest demand and the highest usage
    among all radioisotopes are Technetium-99m and Radioiodine isotopes such as the Iodine-131, Iodine-
    131 MIBG, Iodine-123 and Iodine-123 MIBG. Currently, most of the medical isotopes and
    radiopharmaceuticals are currently imported. Technetium-99m is the backbone of nuclear medicine
    whereby more than 80% of Nuclear Medicine services utilize this radioisotope. Technetium-99m supply
    chain is unstable globally and in coming future, two main reactors (Canada & Holland) that produces
    60% of world Molybdenum-99 will shut down the operation and supply of Molybdenum-99 will be
    disrupted. As for radioiodine services, currently, Iodine-123 can't be obtained in Malaysia and
    neighboring countries due to its short half-life. Iodine-123 is useful in diagnostic of thyroid related
    diseases. As for PET services, the highest demands are F-18 FDG and Gallium-68 Generator for the
    moment. However the survey data still did not, include most of the PET centers in the Klang Valley,
    northern area (Penang) and the new upcoming PET center in Southern Region (Malacca and Johor).
    It is important for Malaysia to self-produced medical radioisotope and radiopharmaceuticals to meet
    the market and local demand of these medical isotopes.
  6. Omar, M., Sulaiman, I., Hassan, A.
    MyJurnal
    The measurements of absorbed dose rate in air around amang plant buildings were carried out using a scintillation detector. It was found that the mean radiation levels at seven amang plants were in the range of 1.6 – 5.5 µGy h -1. The individual maximum value measured was 56 µGy h -1. The annual dose to a worker transporting the minerals to the plant was estimated to be 1.5 mSv y -1.
  7. Halimah Muhamad, Nashriyah Mat, Tan, Yew Ai, Ismail, B.S.
    MyJurnal
    The adsorption equilibrium time and effects of pH and concentration of ¹⁴C-labeled chlorpyrifos
    O,O-diethyl O-(3, 5, 6 trichloro-2-pyridyl)-phosphorothiote in soil were investigated. Two types of Malaysian soil under oil palm were used in this study; namely clay loam and clay soil obtained from the Sungai Sedu and Kuala Lumpur International Airport (KLIA) Estates, respectively. Equilibrium studies of chlorpyrifos between the agricultural soil and the pesticide solution were conducted. Adsorption equilibrium time was achieved within 6 and 24 hours for clay loam and clay soil, respectively. It was found that chlorpyrifos adsorbed by the soil samples was characterized by an initial rapid adsorption after which adsorption remained approximately constant. The percentage of ¹⁴C-labeled chlorpyrifos adsorption on soil was found to be higher in clay loam than in clay soils. Results of the study demonstrated that pH affected the adsorption of chlorpyrifos on both clay loam and clay soils. The adsorption of chlorpyrifos on both types of soil was higher at low pH with the adsorption reduced as the pH increased. Results also suggest that chlorpyrifos sorption by soil is concentration dependent.
  8. Mohd Fazli Zakaria, Lanyau, Tonny, Mohamad Fauzi Saad, Ahmad Razali Ismail
    MyJurnal
    Ageing management is one of the important safety factors to be implemented proactively throughout the lifetime of a research reactor. In order to continue the safe operation of a research reactor from the reactor safety standpoint, a systematic and methodical approach should be taken. In practice, ageing management programme is accomplished by integrating the existing programmes including maintenance, periodic testing and inspection and periodic safety reviews. Such approach will be a good platform for the reactor operation
    and maintenance group to utilize data from existing maintenance programme to be incorporate into the ageing maintenance system. This paper will describe the ageing management programme for Reactor TRIGA PUSPATI (RTP).
  9. Yusof Abdullah, Mohd Reusmaazran Yusof, Azali Muhammad, Nadira Kamarudin, Paulus, Wilfred Sylvester, Nurazila Mat Zali, et al.
    MyJurnal
    The preparation, physical and mechanical properties of Al/B4C composites with 5 and 10 wt.% reinforcement content were investigated. In order to obtain the feedstock with a low powder loading, B4C mixtures containing fine powders were investigated to obtain the optimal particle packing. The experimental results indicated that the fine containing 5 and 10 wt.% particles are able to prepare the feedstock with a good flowability. The composites fabricated by powder metallurgy have low densities and homogeneous microstructures. Additionally there is no interface reaction observed between the reinforcement and matrix by XRD analysis. The hardness of Al/B4C composites prepared by powder metallurgy was high.
  10. Yavar, A.R., S. Sarmani, Tan, C.Y., N.N. Rafie, Lim, S.W. Edwin, Khoo, K.S.
    MyJurnal
    An electronic database has been developed and implemented for ko-INAA method in Malaysia. Databases are often developed according to national requirements. This database contains constant nuclear data for ko-INAA method; Hogdahl-convention and Westcott-formalism as 3 separate command user interfaces. It has been created using Microsoft Access 2007 under a Windows operating system. This database saves time and the quality of results can be assured when the calculation of neutron flux parameters and concentration of elements by ko-INAA method are utilised. An evaluation of the database was conducted by IAEA Soil7 where the results published which showed a high level of consistency.
  11. Afishah Alias, Siti Rahayu Mohd Hashim, Wajir, Julynnie, Fauziah Abdul Aziz, Mihaly, Judith
    MyJurnal
    Unaffected, affected and heavily affected teeth enamel were studied by using FT-Raman spectroscopy. The 14 permanent teeth’s enamel surface were measured randomly, resulting in total n=43 FT-Raman spectra. The results obtained from FT-Raman spectra of heavily affected, affected and unaffected tooth’s enamel surfaces did not show any significant difference. In this study, Kruskal-Wallis and Wilcoxon rank sum tests were used to compare the intensity between the categories of enamel as well as the surfaces of teeth samples.
  12. Azraf Azman, Mohd Rizal Mamat@Ibrahim, Anwar Abdul Rahman, Megat Harun Al Rashid Megat Ahmad, Abdul Aziz Mohamed, Muhammad Rawi Mohd Zin, et al.
    MyJurnal
    The temperature profile of a cryogenic system for cooling of beryllium filter of a small-angle neutron scattering (SANS) instrument of TRIGA MARK II PUSPATI research reactor was investigated using computational fluid dynamics (CFD) modeling and simulation. The efficient cooling of beryllium filter is important for obtaining higher cold neutron transmission for the SANS instrument. This paper presents the transient CFD results of temperature distributions via the thermal link to the beryllium and simulation of heat
    flux. The temperature simulation data are also compared with the experimental results for the cooling time and distribution to the beryllium.
  13. Ahmad Taufek Abdul Rahman, Ahmad Termizi Ramli, Abd. Khalik Wood
    MyJurnal
    Environmental radiation protection program is important in the effort to limit radiation dose to the public to be as low as reasonably achievable. As water is an important factor of transfer of radionuclide to human, therefore it is important to measure natural radionuclide concentrations in rivers. 20 water samples were collected randomly from the main rivers in Kota Tinggi district. The water samples collected were analysed using ICP-MS technique to determine uranium, thorium and potassium concentration in river water. Radionuclide concentrations obtained were compared with the terrestrial gamma radiation dose rate measured in the area. Significance of the results obtained is discussed.
  14. Zaini Hamzah, Che Yasmin Amirudin, Seh Datul Riduan, Ahmad Saat
    MyJurnal
    137 Cs is well known man-made radionuclide produced from nuclear industry. Nuclear weapon tests and nuclear accidents had contributed to presence of 137 Cs into the worldwide environment including Malaysia. It has spread out to the entire world through the air and water current. Since Cameron Highlands is located at high altitude, there is a better chance of the 137 Cs to settle down on the trees and later the soil underneath. In this study, the soil samples were taken at the slopes of two different tea plantation areas namely A and B. The soil samples were oven dried, ground, sieved and packed and sealed properly in plastic containers before measurement. Each plastic container contains around 450 g of sample. The measurement of 137 Cs activity concentration was done using HPGe detector gamma spectrometer. The spectrum was analyzed using Gamma Vision software to calculate the activity concentration of 137 Cs with energy peak of 661.66 keV. The activity concentration of 137 Cs found in the samples ranged from 0.23 to 1.90 and 0.11 to 3.01 Bq/kg for tea plantation A and tea plantation B, respectively. From the activity concentration of 137 Cs result, it was comparable to the others research regarding to 137 Cs in the soil around Asian.
  15. Ahmad Saat, Nor Shazlina Zainal, Zaini Hamzah
    MyJurnal
    Ground water contain natural radioactivity associated with uranium and thorium that present naturally in rocks and soils. Humans may be exposed to the emission of energetic alpha particle from supported radon decaying process in this water when it is inhaled or ingested. Assessment of supported radon in ground water was carried out using fourteen ground water samples from Cameron Highlands. The measurement was accomplished by degassing the water samples using pump and then allowing the gas to flow into specially constructed 0.0191 m8 metal chamber. The activity concentration of supported radon in water sample was measured using continuous radon monitor inside the radon chamber. Measurement was carried out at one hour interval for twenty four hours. The hourly supported radon concentration was found to stabilize after about 8 hours. The stabilized concentration was used to determine supported radon activity concentration in the water samples. Results of the study show that depending on the sampling location, the activity concentrations of supported radon are in the range from 0.09 - 0.48 Bq/L which is lower than the activity concentration of radon in drinking water as proposed by USEPA (11 Bq/L).
  16. Sabar Bauk, Abd. Aziz Tajuddin
    MyJurnal
    The linear and the mass attenuation coefficients of Rhizophora spp. wood in the photon energy range of 11.22 - 28.43 keV were determined. This was done by studying the attenuation of x-ray fluorescent (XRF) photons from selenium, molybdenum, silver and tin targets. Both the Kα and Kβ peaks were utilised. The results were compared with theoretical values for average breast tissues for youngage, middle-age and old-age groups calculated by using a XCOM computer programme. The mass attenuation coefficient of Rhizophora spp. was found to be close to that of the calculated young-age breast in this photon energy range.
  17. Yusof Abdullah, Mohd Reusmaazran Yusof, Azali Muhamad, Zaifol Samsu, Nurhaslinda Ee Abdullah
    MyJurnal
    Boron carbide (B4C) is a ceramic material which is effective to absorb thermal neutron due to wide neutron absorption cross section. In this work, B4C is added into concrete as fine aggregates to test the attenuation properties by getting the attenuation coefficient of the concrete/B4C. The samples of concrete/B4C were exposing to the thermal neutron radiation source (241-Americium-Berylium) at the dos rate of 29.08 mR/h. The result show that the attenuation coefficient of the sample with 20wt% B4C is 0.299cm -1 and the sample without B4C is 0.238cm -1 and hence, concrete/B4C is suitable as a shield for thermal neutron radiation.
  18. Banjuraizah Johar, Hasmaliza Mohamad, Zainal Arifin Ahmad
    MyJurnal
    α Cordierite is very important phase in MgO-Al2O3-SiO2 system because of their very outstanding thermal, chemical and electrical properties. In this presents study nonstoichiometry cordierite (MgO:Al2O3:SiO2 = 3:1.5:5) using 2 different initial raw materials ( (i)mixture of pure oxide, and ii) mainly mixture of minerals) were fabricated and compared in terms of phase transformation and physical properties. Cordierite was prepared by glass method at low melting temperature (1350°C). Low melting temperature has resulted in partly crystalline glass which has possesses higher hardness, required longer milling time and result in contamination from grinding media. However, α-cordierite has successfully crystallized and fully densified at 850°C/2h. Activation energy for densification was investigated from thermal expansion coefficient (TCE) results. Other properties that were discussed included thermal properties using DTA/TGA.
  19. Yusof Abdullah, Abdul Razak Daud, Mohd Harun, Roslinda Shamsudin
    MyJurnal
    Al-Si/SiC composites with the fraction of 5 and 15 wt. % fine SiC particles were fabricated using stir casting process by which SiC powders were poured into aluminium melt and cast in a stainless steel mould to form ingot. Characterization by X-ray diffraction (XRD) analysis showed the presence of constituent and intermetallic materials in the composites. Microstructure study revealed that both fine and course particles scattered in the Al-Si matrix. The characterization of thermal properties showed that the thermal conductivity and coefficient of thermal expansion decreased with the increase in SiC content. The conductivity and expansion behavior is correlated to the microstructure and weight fraction of the SiC particles. Meanwhile, the hardness of the composite increased with the increasing of SiC particles in the composites.
  20. Megat Harun Al Rashid Megat Ahmad, Abdul Aziz Mohamed, Azmi Ibrahim, Che Seman Mahmood, Putra, Edy Giri Rachman, Muhammad Rawi Muhammad Zin, et al.
    MyJurnal
    Alumina powder was synthesized from an aluminum precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was of high purity and highly crystalline D-phase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder.
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