Atom Indonesia (E-Journal)
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Identification, Selection, and Response of Radiation Induced Towuti Mutant Rice (Oryza Sativa L.) in Drought Stress Conditions
Full text linkClimate change with the impact of drought stress has become a major environmental problem for rice (Oryza sativa L.). The use of gamma ray radiation at a dose of 300 Gy is one way to develop drought tolerant rice varieties with little change to the characteristics of the Towuti variety. However, research is still needed to determine its resistance to drought stress. This study aims to identify characters for selection, genotype selection, and determine the response of Towuti mutant rice to drought stress conditions.The characters that can be used to select rice genotypes under drought stress conditions are plant height, number of leaves, number of tillers, and SPAD chlorophyll value. The Towuti mutant has the best tolerance to drought stress compared to other genotypes. Tolerance to drought stress in the Towuti mutant is not caused by the stay-green gene
Scanning Horn Simulation Code for Electron Beam Machine Based on Boris Algorithm
Full text linkA numerical particle simulation code package to estimate the irradiation distribution of an electron beam machine is presented. Particle-to-particle interactions are calculated using particle-in-cell method, while the equation of motion is solved using Boris algorithm. The amplitude of oscillating magnetic field distribution from the scanning horn is obtained using CST magnetic field solver. The code was run using Intel’s i7-10700 processor without multithreading. For cases where particle-to-particle interactions are negligible, the simulation requires about 10 000 seconds to finish. The results show that different shapes of signals will result in different irradiation distributions. For a relatively low magnetic oscillation frequency, it is shown that a triangular signal will result in a more evenly distributed irradiation compared to a sinusoidal signal
The Investigation of Lead Borate Glass Composites for Boron Neutron Capture Therapy Shielding
Full text linkIn this work, we studied the lead borate glass composites to optimize its shielding properties of thermal neutrons and gamma-rays for Boron Neutron Capture Therapy (BNCT) applications. Attenuation coefficients, half-value layer (HVL), and tenth-value layer (TVL) were measured for a broad range of gamma-ray energies, i.e., 356, 511, 662, 1173, 1274, and 1332 keV experimentally. Theoretical results using XCOM software show an agreement with the NaI(Tl) detector-based experimental measurements. The attenuation of collimated thermal neutrons, from Cf-252 source, was simulated using Monte Carlo-based code and compared experimentally with measurements by BF3 detector. A reasonable agreement between simulations and experiments was observed, suggesting that the shielding properties of lead borate glass (LBG) composites are monotonically increasing with the increasing of the lead and boron additives
Effect of Starch and Chitosan Addition on Swelling Properties of Neutralized Poly(Acrylic Acid)-Based Superabsorbent Hydrogels Prepared by Using γ-Irradiation Technique
Full text linkSuperabsorbent hydrogels are polymers with a 3D network that have attracted the attention of scientists and industrialists because of their fantastic ability to absorb and retain water and aqueous solutions. The most widely used and commercially available superabsorbent hydrogels are synthetic K-acrylate materials. In this novel study, superabsorbent hydrogels have been developed using natural ingredients to have more biodegradable properties. Superabsorbent hydrogels were synthesized from acrylic acid, cassava starch, and chitosan using the γ-irradiation method under different experimental conditions. The γ-irradiation technique was chosen to produce hydrogels free of residues that may remain when chemical crosslinkers are used. The effects of irradiation dose, acrylic acid composition, and the amount of cassava starch and chitosan on the characteristics of produced hydrogels were analyzed. The resulting polymers were further characterized by fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) to evaluate the structure. The thermal behavior of superabsorbent products at different neutralization doses was tested with differential scanning calorimetry (DSC). FTIR data indicated that the grafting reaction was successfully implemented in this work. SEM analysis showed that the hydrogel produced from this study was porous and there was a reduction in pore size with the addition of starch and chitosan. It can be concluded that the addition of cassava starch and chitosan affects the acrylic acid-based superabsorbent properties, which are pore size, thermal behavior, gel content, antibacterial activity, and swelling capacity in water, salt, and urea solutions. The best hydrogel was obtained by adding 0.25 g of cassava starch and 0.25 g of chitosan, using 50 % acrylic acid neutralization and 5 kGy γ-irradiation doses. The graft polymers possess the maximum swelling capacity of 670 g/g for distilled water, 520 g/g for NaCl solution, and 767 g/g for urea solution (relative to the dry weight). These products were sterile from Escherichia coli bacteria and had the potential to be applied as superabsorbent resins for various fields
Investigation of Electron Contamination on Flattened and Unflattened Varian Clinac iX 6X and 15X Photon Beam Based on Monte Carlo Simulation
Full text linkThe aim of this study was to characterize electron contamination of a flattened (FF) and an unflattened (FFF) Varian Clinac iX 6X and 15X photon beams using Monte Carlo (MC) simulation. EGSnrc MC technique was used to model the flattened and unflattened head and simulate dose distribution of 6X and 15X of FF and FFF photon beam in water phantom. The materials and geometrical data of FF linac were provided by Tan Tock Seng Hospital (TTSH) Singapore. The FFF linac was modeled by removing the flattening filter component in the FF linac. Phase space files were scored after flattening filter and in the phantom surface. The phsp files were analyzed to characterize the particles produced by the linac head using BEAMDP. The contaminants contribute around 1 % and 2 % in the phsp1 for flattened and unflattened beams, respectively. The photons are scattered in small-angle in the range of 0 – 4o. The contaminant electron contributes up to one hundredth compared to the photons. The increase of field area affects the increase in contaminants and penumbra width due to the increasing number of particle scattered out of the field area. The unflattened beam affects the increase in the number of electron contamination and surface dose. The penumbra width of the flattened beams was smaller than the unflattened beams for the same field size and energy
Safety Investigation of Hazardous Materials Released from the Combined High Temperature Gas Cooled Reactor – Hydrogen Production Plant Using ALOHA Software
Full text linkSafety Investigation of Hazardous Materials Released from The Combined High Temperature Gas Cooled Reactor (HTGR) – Hydrogen Production Plant Using ALOHA software has been carried out. Currently, most of studies for HTGR-hydrogen plant are focused only on the impact of hydrogen presence to the HTGR plant safety. Therefore, the objective of this study was to investigate the effect of the presence of natural gas and synthetic gas from Steam Methane Reforming hydrogen plant on the combine HTGR-Hydrogen production system using ALOHA software. Three selected hazardous materials: CH4, CO and H2 were analyzed. The selected potential hazards of the hazardous materials after leaking from the pipe were downwind suffocation/toxication, flammable area and blast area from vapor cloud explosion. Two types of parameter, i.e., meteorological dispersion (including wind speed, temperature, humidity, nuclear building air changes for day and night) and source release parameters (including pipeline length, and distance from the reactor building to the hydrogen plant), were selected for this study. The effects of the parameters on the hazard distance were then analyzed. The study shows that hydrogen detector needs to be installed at the plant to ensure safety of field operator. Furthermore, CO adsorber and H2 recombiner should be installed at the Reactor HVAC system for CO poisoning and H2 fire protection. Provision of a separation distance of more than 250 meters or construction of a blast barrier between the reactor building and the hydrogen plant is also recommended to protect the reactor from H2 explosion hazard
