JURNAL SAINS NUKLEAR MALAYSIA

THE EFFECT OF PC88A SOLVENT EXTRACTION PARAMETERS AND ITS STRIPPING BEHAVIOR TO THE RECOVERY OF YTTRIUM

Roshasnorlyza Hazan — 2024-10-22

Yttrium (Y) is one of the elements major in heavy rare earth elements (HREE) used in various industries such as metallurgy, steel, laser, electronics, optics, superconductors, magnets, color television (TV) tubes and others applications. In nature, the rare earth elements (REE) are associates in fairly multifaceted combination and because of chemical properties likeness and difficult to isolate REE into single elements. These could be the biggest hurdle in the recovery and extraction of yttrium from xenotime minerals. Therefore, solvent extraction of yttrium from chloride solution using organic extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) diluted in kerosene and modified with isodecanol was investigated in this study. Based to a solvent extraction study, the best conditions for recovering yttrium using an organic combination consisting of 34% PC88A, 6% isodecanol, and 60% kerosene were 1.0 g of yttrium chloric hexahydrate in 0.2 M hydrochloric acid (HCl) with a ratio organic to aqueous of 1:3 and 30 minutes contact time. Additional research on the behavior of stripping was also differentiated and considered. It was discovered that nitride acid (HNO3) were more effective in yttrium stripping than HCl and sulfuric acids (H2SO4).

CALIBRATION OF THERMOLUMINESCENCE OPTICALLY STIMULATED LUMINESCENCE READER USING QUARTZ IN DATING LABORATORY, MALAYSIAN NUCLEAR AGENCY

Mohd Zuhair Mohd Sanusi — 2024-10-23

The TL OSL reader is a tool for dating applications in a variety of fields. One of the main components of an TL OSL reader is the irradiation source. Calibration of irradiation sources for readers can be carried out using quartz. It is important to calibrate the reader before performing the dating method to ensure equivalent dose within the acceptance range. Quartz was measured using the Single Aliquot Regeneration (SAR) protocol. Measurements obtained an average dose rate of 28.87 ± 0.43 Gy (n = 10) with a ratio in the range <5%. In addition, the measurement also found that the value of 2θ is equivalent to 70%. The central point for dose distribution was at 28.30 Gy, with only 3 quartz samples getting dose readings outside the dispersion bar. The overdispersion measured doses were 26.62, 27.68 and 31.56 Gy. The ratio of received dose/measured dose is in the range of 0.887-1.052, which showed that there was no significant signal loss. Therefore, we conclude that this reader is acceptable for carrying out the dating method and it is recommended to use different doses as well as more detailed SAR protocols for further study.

DETERMINATION OF ELEMENT CONTENTS IN COMMERCIAL TEAS MARKETED IN MALAYSIA & ITS INFUSION RESIDUE USING NEUTRON ACTIVATION ANALYSIS (NAA)

Siti Aminah Omar — 2024-10-23

Fifteen elements in black tea, rose flavoured tea and fruit tea commercially sold in Malaysian market were determined using neutron activation analysis (NAA). The elements analyzed include Al, Ba, Br, Ce, Cl, Eu, Fe, K, La, Mg, Mn, Na, Rb, Sc, and Zn. The concentration of these elements varied according to the tea types in the range of 2.2% K to 0.04 mg/kg Sc. The quality of analysis was assured using certified standard reference material. Infusion study of the tea residue was also performed to analyse the possible consumption of these elements by the population. Ce, Cl, Eu, K and Rb were found to be easily infused in all three types of teas. Kruskal-Wallis test found significant differences (p < 0.05) between elemental composition and types of teas. Principal component analysis (PCA) showed clustering based on types of teas.

SPATIAL TRENDS OF NITRATE LEVEL AND NITRATE STABLE ISOTOPES IN THE LINGGI RIVER

Munirah Abdul Zali — 2024-10-23

Determining the isotopic composition of nitrate (δ15N-NO3- and δ18O-NO3-) in water can provide useful information to identify the sources of nitrate pollution and understand its dynamic behaviour in the aquatic ecosystem. In this study, six river water samples from the Linggi River, Malaysia were obtained to determine the nitrate level and understand possible sources of nitrate pollution using nitrate stable isotopes. The nitrate level and nitrate stable isotopes were measured using ion chromatography (IC) and Continuous Flow Elemental Analyzer Isotope Ratio Mass Spectrometer (CF-EA-IRMS) respectively. The nitrate in the river water samples ranged between 0.97± 0.01 mg L-1 and 36.08 ± 0.12 mg L-1. The nitrate level in all river water stations was below than World Health Organization (WHO) and Malaysian Raw Drinking Water guideline level. For nitrate stable isotopes the δ15N-NO3- values ranged from +1.4‰ to +15.6‰ and the δ18O-NO3- values ranged from +13.8‰ to +27.4‰ in the river water samples. Based on the cross plot of nitrate stable isotopes, the Linggi River were influenced by the mixture of nitrate pollution sources process from ammonia in fertilizer, soil ammonia, sewage, manure, nitrate fertilizer and atmospheric nitrate. This study reports the signature of nitrate stable isotopes in potential nitrate pollution sources identificati

IMPROVEMENT IN RADIATION PROTECTION INFRASTRUCTURE FOR X-RAY FACILITIES IN BANGLADESH: THE ROLE OF THE EXECUTIVE REGULATORY AUTHORITY

Md. Kabir Ahamed — 2024-10-23

The national regulatory body in the state regulates the source of ionizing radiation, to optimize exposure for occupational radiation workers and public. The Bangladesh Atomic Energy Regulatory Authority covers all radiological regulatory aspects of ionizing radiation, such as diagnostic X-ray facilities for all practices and intervention requirements. The study presents an assessment and analyses the degree of technical radiation protection requirements and the status of improvement in the national regulatory standards for 230 different facilities in the four particular districts in Bangladesh. The methods used included comprehensive on-site inspections, visual assessments of equipment, operational observations, staff interviews, and technical evaluations. Safety system tests were conducted, and compliance records, licensing, and training programs were reviewed. The main objective is to ensure all the regulatory requirements are being fulfilled by analyzing data on radiation protection matters. In the cases of public and radiation workers, approximately 77% and 56% of dose rates in the examined facilities, respectively, were following the radiological protection technical regulation. However, significant progress has been observed in the facilities in the last few years since the authority initiated the regulatory program.

DOSE RATE PREDICTIVE MODEL OF TERRESTRIAL GAMMA RADIATION BASED ON SUPERFICIAL-WEATHERED SOIL AND ROCKS: CASE STUDY IN SARAWAK, MALAYSIA

Hairul Nizam Idris — 2024-10-23

Estimating terrestrial gamma radiation (TGR) levels is crucial for assessing the annual effective dose received by the public due to natural radiation exposure. Cumulative doses from various sources can become significant, warranting a spatial understanding of TGR distribution. Few countries have comprehensively mapped TGR on a national scale, often facing challenges due to remote or inaccessible regions. This study explores the feasibility of estimating TGR dose rates using a linear regression model based on surface-weathered soils and rocks in Sarawak, Borneo, Malaysia. Geological studies reported that a rich diversity of rock types shaped by complex tectonic history can be found in Sarawak, predominantly sedimentary rocks covering 93% of the region, while igneous and metamorphic rocks constitute the remaining 7%. In this study, a total of 1044 TGR dose rate measurements were collected. The measurement ranges from 7 to 320 nGy h-1, with a mean of 100 nGy h-1.. Non-parametric statistical analyses of variance have validated the notable dissimilarities among six categories of superficial-weathered soil and distinguished the two distinct groupings of sedimentary and igneous rocks. The regression analysis produced a model for predicting TGR dose rates (nGy h–1) = 0.992Dsoil – 0.816Drock + 109. The model showed a sufficient linear correlation, with spatial maps generated from in-situ measurements and the regression model displaying similar regional dose rate contours. Semivariogram analysis supported the model's reliability for predicting TGR dose rates in areas with similar geological backgrounds. In conclusion, this study has successfully developed a predictive model for TGR dose rates in Sarawak, based on superficial-weathered soil and rock data. While the model is specific to the Sundaland-Borneo tectonic block, it provides a valuable tool for spatial inference of TGR dose rates in unsampled locations with similar geological characteristics, aiding in radiation exposure assessment and environmental monitoring.

MODIFICATION OF SILANE-MODIFIED TIO2 NANOPARTICLES WITH APO-NANOPARTICLES AS AN ANTIMICROBIAL ADDITIVE FOR PALM OIL-BASED SURFACE COATINGS

Rida Tajau — 2024-10-23

The resources for palm oil in Malaysia are readily available, renewable, and have lower operating costs than any petrochemical oil resource. In this work, silane-modified anatase titanium dioxide (TiO2) nanoparticles (NPs) were hybridized with acrylated palm olein (APO) (NPs) synthesized by ionizing acrylic palm oil resin to develop an antimicrobial additive for surface coating applications. The effects of their incorporation on the palm oil film coating's layer as well as the physicochemical characteristics of the hybrid APO and TiO2 organic-inorganic NPs composites were investigated. The results included compatibility, chemical properties, morphology, roughness, water contact angle, thermal stability, transmittance, hardness, crosslinking and anti-scratch effects on coating surfaces. The test coating sample, POBUA-IPDI, presented a slightly higher adhesion and good crosslinking density, which improved hydrophobicity, thermal stability, and anti-scratch properties. This could be ascribed to a greater surface tension between the molecular forces of an object and the composite resin in the presence of TiO2-APO NPs compared to other coatings. Antimicrobial features were minimal due to the coating sample's TiO2 low content of 1%. On the other hand, the microbial inhibition zone can be detected due to the natural hydrophobic nature of palm oil and the chemical cross-linking capabilities of coating products after exposure to UV radiation that limit growth or do not allow microbial attachment surrounding the coating layer's surface. The study's findings demonstrated that a palm oil composite coating product by using TiO2 as a nanofiller can improve the product's thermal, mechanical, and antimicrobial properties and has the potential to be employed as a surface protective layer.

MECHANICAL PROPERTIES OF BIO-BASED SELF-HEALING COATING WITH EMBEDDED MICROCAPSULES

N. H. Mudri — 2024-10-23

Self-healing coating is one of the smart coatings that can restore physical appearance and performance after exposure to damage such as scratches and weathering. Self-healing coatings have several benefits, including extending material life and lowering operating costs by reducing the need for planned maintenance, especially in situations involving remote locations. Microcapsule is one of the techniques that are widely used in the preparation of self-healing coating. This approach used an active healing agent to be stored in the microcapsule. In the previous work, pure jatropha oil (JO) and its derivatives known as jatropha oil-based polyurethane acrylate (JPUA) were encapsulated into a polyurea formaldehyde (PUF) microcapsule. In this study, JO and JPUA-IPDI-based microcapsules were loaded into the JPUA-TDI-based coating. 5 wt% and 10 wt% loading of microcapsules were dispersed using a mechanical stirrer in the coating formulation until a homogenous mixture was obtained. The self-healing coating formulation was coated on a steel plate (100 mm x 100 mm x 1.5 mm) using a bar applicator with a thickness of 50 μm,100 μm, 150 μm and 200 μm. Then, the wet film was irradiated under UV light until fully cured. Mechanical tests such as Pendulum Hardness Test (ASTM D4366), Cross-cut Adhesion Test (ASTM D3359-09), Transmittance Test (ASTM E1348), and Haze Test (ASTM D1003) were performed on the cured self-healing coating. The mechanical properties of the self-healing coating were compared with the coating without microcapsule loading as a control. It was found that the hardness value was reduced as the microcapsules were incorporated into the coating formulation in 5% JPUA and 10% JPUA. This trend continuously declined as the coating was thickened from 50 μm to 100 μm, 150 μm and 200 μm in the self-healing coating containing microcapsules. For the adhesion test, Control samples at all of the testing thicknesses showed a 4B adhesion score where less than 5% of the area was removed. A similar grade was displayed by 5% JPUA at 50 μm. The remaining samples indicated deteriorated adhesion properties as the film thickness increased and microcapsule loading increased. The 10% JPUA at a thickness of 200 μm showed the worst adhesion property with 15% to 35% of the removed area. As a conclusion, self-healing coating with 5 wt% loading of JO and JPUA-IPDI-based microcapsule with thickness of 50 μm has maintained the hardness, adhesion, haze, and transmittance properties when compared with the control sample.