Displaying publications 1 - 20 of 95 in total

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  1. 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.
  2. Noraishah Othmanl, Nor Pa' iza M. Hasani, Juhari Mohd Yusof, Roslan Yahya, Mohd Amirul Syafiq
    MyJurnal
    Flow measurement is a critical element for liquid resources monitoring for various applications in many industrial systems. The purposes of the study are to determine the flow rate of liquid system in flow rig using radiotracer techniques and to compare the result with that obtained by the conventional flow meters. The flow rig consists of 58.7m long and 20cm diameter pipeline that can accommodate about 0.296m3 of liquid. Tap water was used as liquid flow in pipeline and conventional flow meters were also installed at the flow rig. Radiotracer was injected as a sharp pulse into the inlet p.peline. The pulse was monitored at the inlet and various points along the outlet pipeline using collimated scintillation detector. The peak to peak and total count methods were applied for radiotracer techniques and showed the comparable results with conventional flow meter.
  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. 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.
  5. 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.
  6. Mohd Fahmi Mohd Yusof, Puteri Nor Khatijah Abd Hamid, Abdul Aziz Tajuddin, Rokiah Hashim, Norriza Mohd Isa
    MyJurnal
    The mass attenuation coefficients of solid water phantoms, Perspex® phantoms and Rhizophora spp. particleboards were determined by using Compton scattering technique measured using Ludlum configuration. The gamma energy of 137Cs sealed source were measured at 30°, 45°, 60° and 75° angles providing scattered gamma energies between 337.72 and 564.09 keV. The mass attenuation coefficients of solid water and fabricated Rhizophora spp. particleboards were the nearest to XCOM values of water with average percentage of discrepancies of 6.8% and 5.9%, respectively. The results indicated similar attenuation properties of solid water and fabricated Rhizophora spp. particleboards and the suitability of the Ludlum configuration to determine the mass attenuation coefficient of materials using Compton scatter technique.
  7. Sakinah Ariffin, Azhar Mohamad, Ratnam, Wickneswari
    Jurnal Sains Nuklear Malaysia, 2012;24(1):91-101.
    MyJurnal
    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.
  8. Shakinah Salleh, Affrida Abu Hassan, Shuhaimi Shamsudin, Yahya Awang, Ab. Kahar Sandrang, Abdullah, Thohirah Lee
    MyJurnal
    Chrysanthemum morfolium is an important temperate cut flower and potted plant for Malaysian local market and exporter. Considering chrysanthemum as a popular vegetatively propagated ornamental plant, induce mutations for breeding purposes are more beneficial. Several of physical mutagens have been used in mutation breeding including x-rays, gamma rays and ion beams. Gamma rays and ion beams are from two different linear energy transfer (LET) which are low and high, respectively. The objective of this study was to compare the effectiveness of acute gamma and ion beam irradiation in generating flower colour mutations on nodal explants of Chrysanthemum morifblium cv. Reagan Red'. The nodal explants were irradiated with acute gamma (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120 Gy) and ion beam (0, 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 10, 15, 20 and 30 Gy). The optimal dose for in vitro shoot regeneration using acute gamma was in the range of 10 to .15.0Gy and for ion beam was between 3.5 to 4.OGv. Relative biological effectiveness for ion beam was found 3.75 higher than the acute gamma. The regenerated plantlets were planted in the greenhouse at MARDI, Cameron Highland for morphological screening. The highest frequency of flower colour mutation for acute gamma was 77.8% whilst for ion beam were between 42.3 to 58.3%.
  9. Shamsiah Abdul Rahman, Md Suhaimi Elias, Nazaratul Ashifa Abdullah Salim, Zalina Laili, Azian Hashim, Shakirah Abd Shukor, et al.
    MyJurnal
    Samples of fine (PM2.5) and coarse (PM10-2.5) fraction of airborne particulate were collected on weekly basis during the period from May 2012 to July 2014 at Bangi, Selangor. The samples were collected using a Gent Stacked Filter Sampler in two fractions of < 2.5 µm and 2.5 - 10 µm sizes. This research paper aims at establishing the concentration level of PM2.5, PM10-2.5 and PM10 at Bangi area and investigates their possible sources and contribution to the ambient aerosol of the area. The samples were analyzed for their elemental composition and black carbon content by Particle Induced X-ray Emission (PIXE) and Smoke Stain Reflectometer, respectively. The average for PM2.5, PM10-2.5 and PM10 ranged from1.8 µg/m3 to 78.0 µg/m3, 9.6 µg/m3 to 76.8 µg/m3 and 12 µg/m3 to 134 µg/m3, respectively. Positive Matrix Factorization (PMF) technique was also applied to fine and coarse data set in order to identify the possible sources of particulate matter (PM) and their contribution to the ambient particulate matter concentrations in the area. The best solution was found to be five factors for both elemental compositions of fine and coarse PM, respectively. The PMF results show that motor vehicles and secondary sulphate contribute about 40.3% and 33.0% of the fine mass respectively followed by soil, sea salt and smoke/biomass burning with the average contribution of 10.5%, 10.3% and 6.4%, respectively. In case of coarse particles the PMF results show that a large fraction of about more than 50% of the coarse mass comes from motor vehicle. Soil dust including road dust and soil construction contribute about 32.5% of the coarse mass whilst the smoke/biomass burning factor contributes about 6.7% of the coarse mass.
  10. Shaiful Azuar Mohamad, Nurul Shahnadz Amir Hamzah, Mohd Yusof Hamzah, Rusli Ibrahim, Khairuddin Abd Rahim, Choong, Yew Keong, et al.
    MyJurnal
    The fermentation of Pleurotus pulmonarius (non-irradiated) and Pleurotus pulmonarius (irradiated) were carried out in Erlenmeyer flask 500 mL (working volume 250 mL) and screened for the presence of β-glucan (1, 3:1, 6). The biomass obtained was extracted using Modified Mizuno Method to get the endopolysaccharide. The endopolysaccharides of Pleurotus pulmonarius (irradiated) contained higher content of β-glucan (1, 3:1, 6) with 16.7 g/100g crude polysaccharide compared to the non-irradiated strain. The irradiated strain was chosen for further investigation. Fractionation of endopolysaccharide Pleurotus pulmonarius (irradiated) using column chromatograph yielded 7 fractions. The first fraction (F1) contained high molecular weight fraction ~ 105 Da which potential immunomodulation characteristics. The Pleurotus pulmonarius (irradiated) was produced in a 5 L air-lift bioreactor. The highest biomass was obtained at air flowrate of 2 L/min, yielding productivity of 2.56 g/L.d.
  11. Pairu Ibrahim, Wan Manshol Wan Zain, Chai, Chee Keong, Sofian Ibrahim, Mohd Noorwadi Mat Lazim, Saadiah Sulaiman
    MyJurnal
    A safety evaluation test on human for latex films made from Radiation Prevulcanized Natural Rubber Latex (RVNRL) with sulfur-containing antioxidant was studied. Sulfur test has confirmed that there was sulfur compound presence in RVNRL derived from antioxidant used in this study. Two types of safety evaluation test were being adopted which are Patch Test and Modified Draize-95 test and this test proved that there is no clinical evidence on the presence of sulfur compound in RVNRL that may induce Type IV allergy in the unsensitized general user population. Both clinical test shows that the highest score value produced by test subjects is 1 and not exceed the allowable limit.
  12. Khairuddin Mohamad Kontol, Ismail Sulaiman
    MyJurnal
    A study to determine whether Radiological Impact Assessment (RIA) is needed for landfill disposal of treated sludge (slag) from oil and gas industries has been carried out. Radioactivity level of slag and soil samples have been measured using gamma spectrometry system and its Total Activity Concentration (TAC) has been calculated. It was found that TAC (inclusive background) was within the control limit set by the AELB i.e. 3 Bq/g as stipulated in LEM/TEK 58 (AELB, 2009). Therefore, as a result from this study, RIA is not required and the allocated area can be used for the landfill disposal of treated sludge (slag).
  13. 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.
  14. Noraishah Othman, Nor Pa’iza Mohamad Hasan, Nazrul Hizam Yusoff, Mohd Amirul Syafiq Mohd Yunos, Engku Mohd Fahmi Engku Chik
    MyJurnal
    Radiotracer technology is a technique of radioactive injection into the systemand the detection is done using radiationdetector.It is alsoa tool for investigating and solving plant process problems namely process malfunctions andmechanical damages. Radiotracer is the most preferred stimulus response techniques in the industries due to its non-invasive application and on line monitoring capabilities, which avoid shut down of the plant. Radiotracer techniques have many advantages, such as high detection sensitivity, in-situ detection, availability of a wide range of compatible radiotracers for different phases, rapid response and high reliability and accuracy of the results. The residence time distribution (RTD) is one of the important parameters that can provide information on the characteristics or hydrodynamics of the nuclear reactor. In this paper, the overall review is presented in brief regarding radiotracer technology in plant operation.
  15. M. Fahmi M. Yusof, Nornashriah A. Rashid, Reduan Abdullah
    MyJurnal
    The glow curve in TLD-100 was compared by applying long preheat time, short preheat time
    techniques and without preheat technique before the TLD readout. Fading effect of the TLD signal
    upon certain storage time with long preheat time (100°C, 10 minutes using the oven) and short
    preheat time techniques (100°C, 10 seconds using the reader) were also studied. 15 TLD-100 chips
    were used with 3 of the TLD chips were used for measuring background radiation. 12 TLD chips
    were annealed, irradiated, preheated long and short preheat time techniques) and analyzed. The TL
    signals output from TLD chips of without preheated were used as the control. Two sets of data were
    taken using TLD chips irradiated with 6 MV and 10 MV photon beams. TL signal output was
    recorded the highest for short preheat time, followed by long preheat time and no preheating. The
    TL signal loss upon certain storage time was also reduced when short preheat time technique was
    applied. By applying long preheat time technique the low temperature peak in the glow curve was
    completely removed for both energies. Whereas, TLD chips exposed to 6 MV and with short preheat
    time technique the low temperature peak did not disappear completely but decreased in intensity as
    compared to the control data by 19.80%, 37.69%, 48.19% and 100% at 24, 48, 72 and 96 hours
    after exposure prior to readout, respectively. Meanwhile, for 10 MV photon beam with short
    preheat time, the small peak intensity was reduced by 19.58% for readout at 24 hours after
    irradiation and 100% for 48,72 and 96 hours delayed time prior to readout. It was observed that
    the TLD-100 was highly dependent on preheat heating time before readout. Short preheat time
    technique was able to reduce post irradiation fading of TLD-100 dosimeters
  16. 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.
  17. Muhamat Omar, Zalina Laili, Julia Abdul Karim, Zarina Masood, Nik Marzukee Nik Ibrahim, Mohd Abd Wahab Yusof
    MyJurnal
    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.
  18. Khairuddin Mohamad Kontol, Ismail Sulaiman, Faizal Azrin Abdul Razalim
    MyJurnal
    Sludge and scales produced during oil and gas production contain enhanced naturally occurring
    radioactive material (NORM). Sludge and scales are under the jurisdiction of Department of
    Environment (DOE) and also Atomic Energy Licensing Board (AELB). AELB has issued a
    guideline regarding the disposal of sludge and scales as in its guideline (LEM/TEK/30 SEM.2,
    1996). In this guideline, Radiological Impact Assessment (RIA) should be carried out on all
    proposed disposals and has to demonstrate that no member of public will be exposed to more than
    1 mSv/y. This paper presented RIA analysis using RESRAD computer code for the disposal of
    treated sludge. RESRAD (RESidual RADioactive) developed by Argonne National Laboratory is to
    estimate radiation doses and risks from residual radioactive materials. The dose received by the
    member of public is found to be well below the stipulated limit.
  19. Raizulnasuha Ab Rashid, Nurul Afifah Aziz, Ili Zawani Khairuddin, Wan Nordiana Wan Abdul Rahman, Norhayati Dollah
    MyJurnal
    Radiobiological model such as linear quadratic (LQ) is widely used in radiotherapy to predict the biophysical response of the tumour cell to the radiation. In clinical radiotherapy, LQ model is widely employed to plan treatment delivery and fractionation. Nevertheless, LQ model might not provide accurate prediction for high dose rate treatment. This study investigates the radiation cell survival responses using LQ model and alternative Multi-Target (MT) model. The experimental works were conducted in-vitro using HeLa cells that were irradiated using photon and electron beams of different energy. Cells irradiation were performed in full scatter condition and exposed to radiation doses ranges from 1 to 10 Gy. Clonogenic assay is used as an endpoint to obtain the cell survival curves which later be fitted with LQ and MT model. The results demonstrate that MT model produce the fitting curves that are closed to the experimental data compare to LQ model especially at high doses. Parameter analysis from both models indicates more biological damage inflicted by high energy electron beam. Correlation between the experimental cell survival data and radiobiological model analysis suggesting that alternative radiobiological model such as MT model could be applied in analysing cells’ radiation survival and damage in clinical radiotherapy.
  20. Mei-Wo Yii, Zal U'yun Wan Mahmood
    MyJurnal
    Natural radioactivityin thesurface soil from thevicinity of Lynas Rare-earth plantin Kuantan, Pahanghad been studied with aim of evaluating environmental radioacitivityof thatarea. The radioactivities of the samples have been measured usinga low-background HPGe gamma detector. The concentration of 226Ra ranged found to be between 8.7 –76.9 Bq/kg (mean 33.7 Bq/kg); activity of 238U from 8.7 to 80.5 Bq/kg (mean 36.9 Bq/kg); as for 232Th, it ranged from 6.2 to 121.5 Bq/kg(mean 58.2 Bq/kg)and that of 40K,the values was from 19.1 to 778.9 Bq/kg (mean of 221.3 Bq/kg). Activity standard deviation for226Ra, 238U, 232Th and 40K were 14.2 Bq/kg, 14.7 Bq/kg, 26.1 Bq/kg and 185.6 Bq/kg, respectively. To evaluate the risk of radiation hazard to human, several parameters, i.e. the radium equivalent activity, External hazard index, Representative level index and dose rate in air from the terrestrial natural gamma radiation were calculatedwith the mean valuesfound to be136.7 Bq/kg, 0.4, 1.0, 65 nGy/h, respectively. The data were discussed and compared with those obtained from the previous studies given in the literatures. Thisstudy found that themean dose equivalent received by an individual at the vicinity area (outdoor) of Lynas plant was estimated to be 82.0 Sv/yr, whichis far below the annual dose limitof1,000 Sv/yrfor general public as stipulated in the national act.
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