Displaying all 11 publications

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  1. Shittu Abdullahi, Supian Samat, Muhamad Samudi Yasir, Aznan Fazli Ismail
    Sains Malaysiana, 2018;47:1017-1023.
    This research reports the annual effective dose of dwellers based on the finding of natural radioactivity concentrations in
    Malaysian tiles. A total of 30 tiles samples obtained from the manufacturer or bought directly from local hardware store.
    Natural radioactivity was analyzed using gamma spectrometry system for 12 h counting times. The activity concentration
    of 226Ra, 232Th, and 40K in the analyzed samples ranged from 37.50 – 158.05 Bq kg-1, 42.22 – 80.19 Bq kg-1 and 349.46 –
    750.18 Bq kg-1, respectively. The determined radium equivalent activity was below than the recommended limit of 370
    Bq kg-1. The external dose received by dwellers due to natural radionuclides in tiles were projected for 1, 5, 10, 20 and
    50 years through six exposure pathways using Resrad-build computer code. The results showed that the annual effective
    dose received by dwellers increased for the investigated timelines but still lower than the annual recommended limit of
    1500 µSv. The simulation result also indicates that radon gas was the primary radiation exposure which contributes
    80-94 % from the total radiation exposure to dwellers.
  2. Teng, Iyu Lin, Ismail Bahari, Muhamad Samudi Yasir
    MyJurnal
    In Malaysia, mineral processing plant is one of the Naturally Occurring Radioactive Material (NORM) processing industries controlled by the Atomic Energy Licensing Board (AELB) through the enforcement of Atomic Energy Licensing Act 1984 (Act 304). The activities generated waste which is called as TENORM wastes. TENORM wastes are mainly found in thorium hydroxide from the processing of xenotime and monazite, and iron oxide and red gypsum from the processing of ilmenite. Other TENORM wastes are scales and sludge from the oil and gas industries, tin slag produced from the smelting of tin, and ilmenite, zircon,
    and monazite produced from the processing of tin tailing (amang). The environmental and radiological monitoring program is needed to ensure that the TENORM wastes did not caused any contamination to the environment. The wastes vary in the types of samples, parameters of analysis as well as the frequency of monitoring based on license’s conditions issued by the AELB. The main objective of this study is to assess the suitability of license’s condition and the monitoring program required in oil and gas, and mineral processing
    industries. Study was done by assessing the data submitted to the AELB in order to comply with the licensing requirement. This study had found out that there are a few of license’s conditions that need to be reviewed accordingly based on the processing activity.
  3. Muhamad Samudi Yasir, Amran Ab Majid, Redzuwan Yahaya
    MyJurnal
    The main component of most building materials in Malaysia is rocks. These rocks have been found to naturally contain U-238, Th-232 and K-40. In order to estimate the radiological impact to the dweller, the level of radionuclides present in various building materials available in Malaysia were analyzed using gamma spectrometry. The radiation hazard indexes were calculated based on the above results. The results showed that the activity concentration of natural radionuclides U-238, Th-232, K-40 were between 19.0 Bq/kg – 42.2 Bq/kg, 16.5 Bq/kg –28.8 Bq/kg and 243.3 Bq/kg – 614.2 Bq/kg respectively. On the whole the radionuclides concentrations were still below the global average of 50 Bq/kg, 50 Bq/kg and 500 Bq/kg for U-238, Th-232 and K-40 respectively. The radiation hazard indexes of the building materials were also lower than the maximum value suggested.
  4. Abubaker Ali Yousif, Ismail Bahari, Muhamad Samudi Yasir
    MyJurnal
    To quantify the effectiveness of deuterons and helium particles at low doses, the inactivation rate in
    vitro for V79 cells has been extracted from radiobiological published data. The Physical parameters
    characteristics of these charged particles such as the linear energy transfer, the restricted linear
    energy transfer, the linear primary ionization and the mean free path are determined. The
    relationship between the inactivation rate and the physical parameters for deuterons and heluim-3
    particles has been established in this research. This approach enables in getting the distinctive
    biological response in terms of varies physical quality parameters. The best statistical regression
    fittings are formulated for each correlation.
  5. Zalina Laili, Muhamad Samudi Yasir, Mohd Abdul Wahab Yusof
    Sains Malaysiana, 2017;46:1617-1623.
    The influence of water-to-cement ratio (w/c) on the compressive strength of cement-biochar-spent resins matrix was
    investigated. Spent resins waste from nuclear reactor operation was solidified using cement with w/c ranging from 0.35
    to 0.90 by weight. In this study, biochar was used as a cement admixture. Some properties of spent resins and biochar
    were determined prior to the formulation study. Compressive strength of harden cement-biochar-spent resins matrix
    was determined at 28 days. The compressive strength of cement-biochar-spent resins matrix was found to depend on the
    w/c and the amount of spent resins added to the formulation. The immersion test of cement-biochar-spent resins matrix
    showed no significant effects of cracking and swelling. The compressive strength of the cement-biochar-spent resins
    matrix increased after two weeks in water immersion test.
  6. Esther Phillip, Muhamat Omar, Muhamad Samudi Yasir, Mohd Zaidi Ibrahim, Zalina Laili
    MyJurnal
    Effect of AP+, Ca", Cu" and Fe" on the removal of radium-226 from radium-contaminated soil using humic acid extracted from a Malaysian peat soil was investigated using batch washing method. The concentration of Al,+ Ca", Cu" and Fe" ranged from 0 to 100 ppm. The radioactivity concentration of radium-226 was determined by gamma spectrometer. The removal of radium-226 was enhanced in the presence of AP' with concentration between 20 - 60 ppm. Meanwhile, higher concentration of 80 - 100 ppm did not lead to further increase in the removal of radium-226. The removal of radium-226 was decreased in the presence of Ca" and Cu". In the presence of Fe" with concentration between 20 - 60 ppm, decrease in the removal of radium-226 was also observed. Nevertheless, at concentration between 80 - 100 ppm, the presence of Fe" led to increase in the removal of radium-226.
  7. Aznan Fazli Ismail, Muhamad Samudi Yasir, Amran Abd. Majid, Redzuwan Yahaya, Ismail Bahari
    Selain daripada batu-batu kecil, batu kerikil dan pasir, simen merupakan salah satu bahan penting untuk membina bangunan. Simen diperbuat daripada campuran batuan dan tanah dan diketahui secara semulajadinya mengandungi radionuklid tabii. Kajian ini bertujuan untuk menentukan aras keradioaktifan tabii serta menilai hazard sinaran yang berpunca daripada radionulid tabii di dalam simen Portland di Malaysia. Sampel simen Portland diperolehi dari kilang pengeluar simen atau dibeli di pasaran tempatan. Kepekatan radionuklid tabii bagi 226Ra (siri 238U), 232Th dan 40K ditentukan dengan menggunakan spektrometri sinar gama. Hasil kajian mendapati julat kepekatan aktiviti bagi 226Ra (siri 238U), 232Th dan 40K masing-masing adalah 7.76 – 82.91 Bq kg-1, 9.79 – 49.37 Bq kg-1 dan 81.89 – 377.10 Bq kg-1. Purata nilai kesetaraan radium berada dalam julat 35.36 ± 0.60 hingga 135.94 ± 15.27 Bq kg-1 manakala julat purata bagi dos setara tahunan dan indeks hazard dalaman adalah masing-masing ialah 80 ± 2 hingga 300 ± 30 μSv tahun-1 dan 0.12 ± 0.00 hingga 0.56 ± 0.07.
  8. Aznan Fazli Ismail, Amran Ab. Majid, Muhamad Samudi Yasir, Redzuwan Yahaya, Ismail Bahari
    Penggunaan bahan binaan yang mengandungi bahan radioaktif tabii (NORM) yang tinggi boleh meningkatkan kadar dos dedahan kepada penghuni di dalam sesebuah bangunan. Kebimbangan terhadap impak radiologi kepada penghuni menyebabkan perlunya dilakukan penilaian hazard radiologi yang berpunca daripada bahan binaan. Sehubungan itu, objektif kajian ini adalah untuk menentukan aras keradioaktifan tabii dalam bahan binaan di Malaysia serta menilai risiko radiologi yang diterima oleh penghuninya. Sebanyak 46 sampel pasir, 43 sampel kerikil dan 13 sampel simen Portland telah dianalisis menggunakan sistem spektrometri sinar gama. Hasil kajian mendapati kepekatan aktiviti bagi ketiga-tiga sampel bahan binaan berada pada julat 4.4 Bq kg-1 hingga 354.9 Bq kg-1, 2.4 Bq kg-1 hingga 263.9 Bq kg-1 dan 15.1 Bq kg-1 hingga 1931.7 Bq kg-1 bagi masing-masing 226Ra, 232Th dan 40K. Pengiraan kadar dos dedahan dalam bangunan mendapati semua sampel menghasilkan dos di bawah nilai 1500 μSv tahun-1, iaitu jumlah had dos yang disyorkan bagi bahan binaan. Hasil analisis ke atas nilai indeks aras perwakilan sinar gama, indeks hazard luaran dan indeks hazard dalaman mendapati sebahagian sampel memberikan bacaan melebihi nilai satu, iaitu had yang ditetapkan bagi bahan binaan. Penilaian risiko radiologi kepada penghuni dengan menggunakan kod komputer Resrad-Build mendapati kadar dos dedahan yang berpunca daripada simen Portland, pasir dan batu kerikil meningkat pada setiap tahun sepanjang tempoh 50 tahun.
  9. Zalina Laili, Muhamad Samudi Yasir, Muhamat Omar, Mohd Zaidi Ibrahim, Philip E
    Sains Malaysiana, 2010;39:333-336.
    This study examines the influence of humic acids (HA) on adsorption of radium (Ra) ions onto coir pith (CP) in aqueous solution. The adsorption behaviours of Ra ions onto CP under the influence of HA in aqueous solution were investigated in the series of batch mode adsorption experiments. The effects of various experimental conditions such as pH, contact time, adsorbent dosage and initial concentration of Ra ions have been studied. The results revealed that the presence of HA in aqueous solution enhanced the adsorption of Ra ions onto CP. The adsorption results showed that the percentage of Ra adsorbed was increased with an increase in the pH or alkalinity of aqueous solutions. Time dependence of the batch studies showed that a contact time of one day was sufficient to reach equilibrium. The result also showed that there was no significant difference on the effect of adsorbent dose on adsorption of radium onto CP. It was shown that the equilibrium data could be fitted by Freundlich equation.
  10. Khoo KS, Nur Farhana Amari, Tan CY, Shahidan Radiman, Redzuwan Yahaya, Muhamad Samudi Yasir
    Sains Malaysiana, 2013;42:167-173.
    Combination of magnetic and biocompatible materials to form core-shell nanomaterials has been widely used in medical fields. These core-shell magnetic biomaterials have a great potential for magnetic fluid hyperthermia (MFH) treatment to remedy cancer. The aims of this study were to investigate the production of core-shell cobalt ferrite/polycaprolactone (CoFe2O4/PCL) nanomaterials with different ratios of cobalt ferrite to caprolactone, to study the effects of using polymer in reducing the agglomerations between particles and to determine the structure, morphology, thermal and magnetic properties of these core-shell nanomaterials. The core-shell nanomaterials were produced by in situ polymerization method. The formation of the CoFe2O4/PCL was investigated by means of Fourier transform infrared spectroscopy (FTIR), x-ray diffractometer (XRD) and transmission electron microscopy (TEM). Its thermal properties were determined by using thermogravimetric analyzer (TGA). The vibrating sample magnetometer (VSM) was used to reveal the magnetic properties. The results for the XRD and FTIR spectra demonstrated the formation of cobalt ferrite and polycaprolactone in core-shell nanomaterials. From the TEM results, it was seen that the core-shell CoFe2O4/PCL nanomaterials were best formed at a ratio of CoFe2O4 to monomer caprolactone mixtures of 1:4.
  11. 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.
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