Effects of 3 MeV electron (10 mA) irradiation at room temperature on the phase, microstructure,
electrical and life time properties of 4H-SiC wafer were investigated by scanning electron
microscopy (SEM), X-ray diffraction (XRD), four point probe current-voltage measurements and
positron annihilation spectroscopy. It was found that irradiation damage in SiC wafer is
significantly increased with the increase of radiation dose as observed in SEM. Irradiation also
resulted in modification of crystallite size as identified by XRD. The resistance of a sample before
irradiation was found to be 0.8 MΩ, whereas for a sample irradiated at 200 kGy, the resistance as
measured by four point probe was 5.2 MΩ. It seems that the increase of resistance hence, reduction
in conductivities could be due to defects induced by the radiation dose received then created
leakage currents at both reverse and low-forward biases and creation of traps in the SiC.
Meanwhile positron annihilation spectroscopy (PAS) was used to analyse the life time of irradiated
samples which nonetheless shows that all irradiated sample have similar life time of 151 ps. It was
observed that that no degradation process of materials experienced by SiC wafer irradiated at 500
kGy.
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.
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).
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.
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.
The acrylated palm oil (APO) nanoparticle is a potential product that can be used as carriers in
medical field. The main focus of the present study was to study the potential of the APO
nanoparticles for used in a controlled drug delivery system. The microemulsion system is used as a
medium to incorporate an active substance such as Thymoquinone (TQ) into the APO polymeric
micelle and then the radiation technique is used as a tool for the synthesis of TQ-loaded APO
nanoparticle. The nano-size TQ-loaded APO particles resulted the particle size of less than 150 nm
with spherical in shape. The TQ release profile was carried out in potassium buffer saline (PBS)
solutions (pH 7.4) at 37
oC. And, the zero-order model has been used to determine the mechanism
of the drug release from the corresponding nanoparticles, respectively. The TQ release was found
to be sustained and controlled in pH 7.4. At pH 7.4, the release of TQ followed the zero-order
model. The in-vitro drug release study showed a good prospect of the APO nanoparticle on being a
potential drug carrier as there are toxic against colon cancer cells and not toxic towards normal
cells. This suggested that the APO product produce using this radiation technique can be
developed into different type of carrier systems for controlled drug release applications.
Haruan or Channa striatus is source of protein that is widely consumed in the region and its extract
is well known for having medical values. It is of great advantage if this product could be taken
orally rather than by injection because the oral route of drug delivery is still preferred by the vast
majority of patients. However protein and peptides can be denatured or degraded by the acidic pH
of the stomach and the presence of endogenous enzymes. In order to protect or prevent digestion
and degradation of the protein in the stomach and to ensure the protein reaches the gastro
intestinal (GI) tract, Carboxymethyl Starch (CMS) nanogel system was developed using electron
irradiation method. However stability of HTE during the irradiation process needed to be studied
before being developed further. In this study, the HTE was irradiated using electron beams. Its
stability was analysed in terms of physical and chemical changes by looking at colour difference,
melting point by using Differential Scanning Calorimetry (DSC) and molecular bonds by using
Fourier Transform Infrared (FTIR) respectively. The results of this study were that no apparent
colour difference was observed with HTE before and after irradiation. These observations were
supported by the FTIR and DSC results that showed that there were no changes in molecular bonds
and melting point, compared between no irradiation and irradiation HTE during electron
irradiation up to 10 kGy. Statistically the test showed no significant difference at p < 0.005 between
melting temperatures.
Peroxide pre-vulcanized natural rubber latex prepared by using gamma irradiation technique is an alternative over the conventionally prepared peroxide pre-vulcanized that used activator to promote the peroxide decomposition in natural rubber latex. Through this technique the problems aroused by some activators such as tends to darken the natural rubber latex film during the drying process can also be overcome. For this preliminary study, data obtained from crosslink density and mechanical measurements were used to evaluate the effectiveness of gamma irradiation in the vulcanization process. Increasing the quantity of tert-butyl hydroperoxide (t-BHPO) from 0.1 pphr to 0.3 pphr while the irradiation dose maintain at 12 kGy has successfully delivered peroxide vulcanized natural rubber latex films with average tensile strength, modulus @ 500% and modulus @ 700% around 15.33, 1.01 and 3.42 MPa, respectively. The effective pre-vulcanization irradiation dose with respect to maximum crosslinking density (85.8 %) was observed on film prepared at 0.1 pphr t-BHPO.
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.
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.
Gamma irradiation is widely used in sterilizationand mutagenesis,especially for plant breeding and crop protection. Microbial mutagenesisthrough gamma irradiation is mainly applied in fermentation industry. In agriculture, gamma irradiation is mostlyapplied in cropimprovement. Microbial mutagenesis is mainly applied against fungus and spore-forming bacteria,which are resistant to gamma irradiation.Response of microbes to gamma irradiation varies and depends on various factors. Reviewof previous works on gamma irradiation for microbial mutagenesis in agriculture may provide some information for the use of this method. Thegeneral view ongamma irradiation, its application,and mutagenesis are discussedin this paper. Further investigation onmicrobial mutagenesis should consider molecular changes,information on which is lacking in previous works.Moreover, studies on microbial mutagenesis are still lacking in Malaysiadespite having severalgamma irradiation facilities.Therefore, further studies on microbial mutagenesis should be conducted.
This study was conducted to evaluatethe nitrogen use efficiency and 13C isotope discrimination of rice mutant lines viz.NMR151 and NMR152. Both cultivars are developed under rice radiation mutagenesis programme for adaptability to aerobic conditions. In the present study, NMR151 and NMR152 were grown under conditions of varying water potentials and nitrogen levels in a shade house. The rice mutant lines were planted on sandy loam soil. Three watering regimes and three nitrogen levels in a completely randomized design with three replications were carried out. The rice mutants were grown for 110 days under three water potentials, (i) Field capacity from 0 to 40 DAS and saturated from 41 to 110 DAS [ST], (ii) Field capacity from 0 to 110 DAS [FC], and (iii) Field capacity from 0 to 40 DAS and 70% of field capacity from 41 to 110 DAS [SS]. Direct 15N isotopic tracer method was used in this study, whereby the 15N labelled urea fertilizer 5.20% atom excess (a.e) was utilized as a tracer for nitroge nuse efficiency study (NUE)by the test crops. 15Nisotope presence in the samples was determined using emission spectrometry and percentage of total nitrogen was determined by the Kjeldahl method. 15N a.e values of the samples were used in the determination of the efficiency of N used by the mutant varieties. The 13C isotope discrimination (Δ13C) technique was used as a tool to identify drought resistance rice species with improves water use efficiency (WUE). WUE is the ratio of the biomass produced by the water consumed. For 13C discrimination analysis, a sample of rice leaf was analyzed for 13C content by using Isotope Ratio Mass Spectrometer (IRMS).The parameter, viz. plant height, number of tillers, grain yield, 1000 grain weight, NUE, Δ13Cand WUE were recorded. Results from this study showed nitrogen rates imparted significant effects on plant height, number of tillers, grain yield, 1000 grain weight and WUE, while water potentials had significant effects on plant height, grain yield, 1000 grain weight, NUE, Δ13Cand WUE. Δ13C has a low but significantly negative relationship with WUE. Rice mutants NMR151 and NMR152 were found to be not significantly different except for their NUE.
The research on radiation induced mutation has been conducted as one of the promising method of plant breeding in Malaysia since 1980s. Nuclear Malaysia is leading research institute inMalaysia conducting plant mutationbreeding research. Gamma Greenhousefacility located in Nuclear Malaysiais one of the irradiation facilitiesto serve as a chronic irradiation facility for inducing mutation in various organisms including plants, fungi and microbes.Chronic irradiation refers to the exposure of materials at a lower dose rate over a long period of time. Previous studies have shown that this type of irradiation can minimize radiation damages to living materials and produces a wider mutation spectrum, therefore is very useful for trait improvements in irradiated organisms. Experiments on induce mutation using Gamma Greenhouse facility for crop improvement program have been conducted since its first operation in 2009. Various plant species including ornamental and herbal plants, food crops and industrial crops have been irradiated to improve their traits such as higher yield and biomass, pest and disease tolerance, higher bioactive compounds, longer bloom time and many others. Most of these crop improvement programs were done through collaborations with other agencies in Malaysia such as universities, research institutes and government departments. A number of publications on crop improvement using Gamma Greenhouse have been published inlocal and international journals as well as seminar presentations at national and international levels. The outputs from induced mutation via chronic radiation using Gamma Greenhouse could be of great interest for plant breeders dealing with improvement and development of new cultivars. This paper discusses the activities and achievement in plant breeding and improvement using Gamma Greenhouse Facility in Malaysia.
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.
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.
Heel Effect is the well known phenomena in x-ray production. It contributes the effect to image
formation and as well as scattered radiation. But there is paucity in the study related to heel effect.
This study is for mapping and profiling the dose on the surface of water phantom by using mobile
C-arm unit Toshiba SXT-1000A. Based on the result the dose profile is increasing up to at least
about 57% from anode to cathode bound of the irradiated area. This result and information can be
used as a guide to manipulate this phenomenon for better image quality and radiation safety for
this specific and dedicated fluoroscopy unit.
Many times a year natural gas transmission and distribution companies need to make new connections to pipelines to expand or modify their existing system through hot tapping procedure. This procedure involves the installation of a new pipeline connection while the pipeline remains in service, flowing natural gas under pressure. The hot tap procedure includes attaching a branch connection and valve on the outside of an operating pipeline, and then cutting out the pipe-line wall within the branch and removing the wall section, which is called object of coupon through the valve. During the hot tapping process a critical problems occurred when a coupon fell into the mother pipeline. To overcome this problem, a gamma-ray absorption technique was chosen whereby a mapping technique will be done to detect the coupon position. The technique is non-destructive as it applies Co-60 (5mCi) as a radioisotope sealed source to emit gamma radiation and a NaI(Tl) scintillation as detector. The result provided a visible representation of density profile inside pipeline where the coupon location can be located. This paper provides the detail of the technique used and presents the result obtained.
Mixed organic liquid waste generated from health-care and research activities containing tritium, carbon-14, and other radionuclide posed specific challenges in its management. Often, this waste becomes legacy waste in many nuclear facilities and being considered as ‘problematic’ waste. One of the most important recommendations made by IAEA is to perform multistage processes aiming at declassification of the waste. At this moment, approximately 3000 bottles of mixed liquid waste, with estimated volume of 6000 litres are currently stored at the National Radioactive Waste Management Centre, Malaysia and some have been stored for more than 25 years. The aim of this study is to develop a characterization protocol towards reclassification of these wastes. The characterization protocol entails waste identification, waste screening and segregation, and analytical radionuclides profiling using analytical procedures involving gross alpha beta, and gamma spectrometry. The results obtained from the characterization protocol are used to establish criteria for speedy classification of the waste.
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.
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.
Radiation Monitoring System aims to limit the exposure dose to personnel to the lowest level
referring to the concept of ALARA (As Low As Reasonably Achievable). Atomic Energy Licensing
(Basic Safety Radiation Protection) Regulations 2010 is useful to control employee and public
radiation protection program and guideline. This paper discussed the methodology and
implementation of the radiation protection program at PUSPATI TRIGA Reactor (RTP) which is
implemented in Nuklear Malaysia, Complex Bangi.