• Journal of Radiation Protection and Research
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• v.46 no.1
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• pp.8-13
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• 2021

Background: Salmonella enteritidis (SE) was the main cause of the pandemic of foodborne salmonellosis. The surface of eggs' shells can be contaminated with this bacterium; however, washing them with sodium hypochlorite solution not only reduces their flavor but also heavily impacts the environment. An alternative to this is surface sterilization using low-energy electron beam. It is known that irradiation with 1 kGy resulted in a significant 3.9 log reduction (reduction factor of 10,000) in detectable SE on the shell. FAO/IAEA/WHO indicates irradiation of any food commodity up to an overall average dose of 10 kGy presents no toxicological hazard. On the other hand, the Food and Drug Administration has deemed a dose of up to 3 kGy is allowable for eggs. However, the maximum dose permitted to be absorbed by an edible part (i.e., internal dose) is 0.1 Gy in Japan and 0.5 Gy in European Union. Materials and Methods: The electron beam (EB) depth dose distribution in the eggshell was calculated by the Monte Carlo method. The internal dose was also estimated by Monte Carlo simulation and experimentation. Results and Discussion: The EB depth dose distribution for the eggshells indicated that acceleration voltages between 80 and 200 kV were optimal for eggshell sterilization. It was also found that acceleration voltages between 80 and 150 kV were suitable for reducing the internal dose to ≤ 0.10 Gy. Conclusion: The optimum irradiative conditions for sterilizing only eggshells with an EB were between 80 and 150 kV.

• Preventive Nutrition and Food Science
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• v.10 no.4
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• pp.378-381
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• 2005

Actin and myosin solutions and fresh ground pork were irradiated with the electron beam (e-beam) at a dose of 0, 1.5, 3.0, 5.0 and 10 kGy. The changes in SDS-PAGE pattern of 2 proteins and the salt-soluble proteins extracted from ground pork after e-beam irradiation were monitored. When the myosin solution was irradiated with e-beam, myosin was degraded completely. Complete myosin degradations were observed even with the lowest dose (1.5 kGy) of e-beam treatment. Actin was degraded with the irradiation, but to a less extent than myosin was. The degradation of actin increased as the e-beam treatment increased from 1.5 to 10.0 kGy. Among the salt-soluble proteins extracted from ground pork, myosin was degraded gradually when the e-beam dose increased from 1.5 up to 10.0 kGy. Similar gradual increase in the degradation of actin also occurred with the increase of irradiation. Increases of 2 low molecular weight compounds (<29 kDa) were observed when the irradiation dose increased from 1.5 to 10.0 kGy. These 2 molecules are thought to be the breakdown products produced from the degradation of major salt-soluble proteins, myosin and actin. The salt-soluble protein content of ground pork did not change with the e-beam irradiation.

• Electrical & Electronic Materials
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• v.10 no.8
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• pp.756-762
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• 1997

In this paper the change of electrical properties of transformer oil due to electron beam irradiation is investigated. The specimens are produced with a some different dose of 0.5[Mrad], 1[Mrad] and 2[Mard] except for original specimen. The physical properties of each specimen is analyzed by using the FT-IR spectrum. So it is confirmed that carbonyl groups are increased according to the increase of electron beam dose and also that the nitric compounds are disappeared. The magnitude of dielectric dissipation factor appears maximum value by the contribution of dipoles and ions in the low temperature low voltage region and it is stable due to the saturation of carriers in the high temperature high voltage region in the electric conduction characteristics. Volume resistivity is also measured one of original specimen is larger than irradiated specimen.

• Food Science of Animal Resources
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• v.18 no.3
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• pp.232-239
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• 1998

This experiment was conducted to investigate radurization effects of gamma ray and electron beam irradiation at 1.5 and 3.0 kGy on beef steaks during 8 days of storage at 5$^{\circ}C$. Total bacteria count, psychrotrophs, mesophiles and thermophiles were analyzed at 2 days intervals. Nonirradiated beef steak was used a scontrol Total bacteria counts, psychrotrophs, mesophiles and thermophiles of the control samples showed 3.03∼4.72 logCFU / g at 0 day and increased to 7.67∼10.90 logCFU / g during 8 days storage except thermophiles. Total bacteria counts, psychrotrophs and mesophiles of beef steaks at 8 days were significantly (p＜0.05) decreased to 3.61∼5.43 logCFU / g by gamma ray and to 3.83∼7.02 logCFU / g by electron beam irradiation at 1.5 and 3.0 kGy. Thermophiles of all irradiated samples at any dose were not detectable through 8 days storage. These results suggested that both gamma ray and electron beam irradiation were effective to extend lag phase of bacterial growth of refrigerated beef. Gamma ray irradiation was better than electron beam irradiation in terms of radurization effects of beef.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.211-215
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• 1996

In this paper, the volume resistivity of transformer oil is made researches so that the electrical properties for transformer oil is investigated. The specimen is produced by the irradiation of electron beam classified into the low dose, such as 0.5[Mrad], 1[Mrad], 2[Mrad]. The effect of electron team irradiation is studied by investigating the electrical properties of dielectric liquid due to the difference of electron beam dose. To measure the physical properties of transformer oil, courier Transform-Infrared Spectroscopy is investigated. And the study far the electrical properties is made by measuring the volume resistivity of each specimen. By means of the result from this experiments, it is introduced that the movement of carrier to contribute to the volume resistivity on the electrical properties.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.376-381
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• 2004

The use of electron beam irradiation was investigated to disinfect total coliforms in the secondary sewage treatment effluent. Unchlorinated secondary effluent was irradiated at different dose of 0.2~1.0 kGy by 1 MeV, ELV-4 Model electron beam accelerator. It is interesting to note that a 100 % reduction in total coliforms and total colonies were achieved until a dose of approximately 0.8 kGy. Even at low dose of 0.2 kGy, the total coliforms and total colonies were successfully inactivated to the level of satisfying the new effluent discharge guideline. Besides disinfection of total coliforms, approximately a 50% removal in biochemical oxygen demand was pronounced at a dose of 0.2 kGy. More than 20 % removal in suspended solids and turbidity was also observed at a dose of 1.0 kGy. The application of electron beam irradiation appeared to be one of options to reuse sewage treatment effluent as agricultural or industrial water.

• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.205-214
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• 2014

Purpose: Phytosanitary irradiation treatment can effectively control regulated pests while maintaining produce quality. The objective of this study was to establish the best irradiation treatment for mangosteen, a popular tropical fruit, using a Monte Carlo simulation. Methods: Magnetic resonance image (MRI) data were used to generate a 3-D geometry to simulate dose distributions in a mangosteen using a radiation transport code (MCNP5). Microsoft Excel with visual basic application (VBA) was used to divide the image data into seed, flesh, and rind. Radiation energies used for the simulation were 10 MeV (high-energy) and 1.35 MeV (low-energy) for the electron beam, 5 MeV for X-rays, and 1.25 MeV for gamma rays from Co-60. Results: At 5 MeV X-rays and 1.25 MeV gamma rays, all areas (seeds, flesh, and rind) were irradiated ranging from 0.3 ~ 0.7 kGy. The average doses decreased as the number of fruit increased. For a 10 MeV electron beam, the dose distribution was biased: the dose for the rind where the electrons entered was $0.45{\pm}0.03$ kGy and the other side was $0.24 {\pm}0.10$ kGy. Use of an electron kinetic energy absorber improved the dose distribution in mangosteens. For the 1.35 MeV electron beam, the dose was shown only in the rind on the irradiated side; no significant dose was found in the flesh or seeds. One rotation of the fruit while in front of the beam improved the dose distribution around the entire rind. Conclusion: These results are invaluable for determining the ideal irradiation conditions for phytosanitary irradiation treatment of tropical fruit.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.29-36
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• 1983

The treatment of tumors along curved surfaces with stationary electron beams using cone collimation may lead to non-uniform dose distributions due to a varying air gap between the cone surface and patient. For large tumors, more than one port may have to be used in irradiation of the chest wall, often leading to regions of high or low dose at the junction of the adjacent ports. Electron-beam arc therapy may elimination many of these fixed port problems. When treating breast tumors with electrons, the energy of the internal mammary port is usually higher than that of the chest wall port. Bolus is used to increase the skin dose or limit the range of the electrons. We invertiaged the effect of various arc beam parameters in the isodose distributions, and combined into a single arc port for adjacent fixed ports of different electron beam eneries. The higher fixed port energy would be used as the arc beam energy while the beam penetration in the lower energy region would be controlled by a proper thickness of bolus. We obtained the results of following: 1. It is more uniform dose distribution of electron to use rotation than stationary irradiation. 2. Increasing isocenter depth on arc irradiation, increased depth of maximum dose, reduction in surface dose and an increasing penetration of the linear portion of the curve. 3. The deeper penetration of the depth dose curve and higher X-ray background for the smaller field sized. 4. If the isocenter depth increase, the field effect is small. 5. The decreasing arc beam penetration with decreasing isocenter depth and the isocenter depth effect appears at a greater depth as the energy increases. 6. The addition of bolus produces a shift in the penetration that is the same for all depths leaving the shape of the curves unchanged. 7. Lead strips 5 mm thick were placed at both ends of the arc to produce a rapid dose drop-off.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.337-344
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• 2018

Food irradiation is important not only in ensuring safety but also improving antioxidant activity of peaches. Our objective was to establish the best irradiation treatment for peaches by calculating dose distribution using Monte Carlo simulation. 3-D geometry and component densities of peaches, extracted from CT scan, were entered into MCNP to obtain simulated dose distribution. Radiation energies for electron beam were 1.35 MeV (low energy) and 10 MeV (high energy). Co (1.25 MeV) and the Husman irradiator, containing three sealed Cs source rods in an annular array, were used for gamma irradiation. At 1.35 MeV electron beam simulation, electrons penetrated well beyond the peach skin, enough for surface treatment for microorganisms and allergens. At 10 MeV electron beam simulation, for top-beam only treatment, doses at the core were the highest and for double beam treatment, the electron energy was absorbed by the entire sample. At Co source, the radiation doses were presented on the whole area. At Cs source, the dose uniformity ratios were 2.78 for one source and 1.48 for three ones at 120 degrees interval. Proper control of irradiation treatment is critical to establish confidence in the irradiation process.

• Journal of Biosystems Engineering
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• v.38 no.2
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• pp.87-94
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• 2013

Purpose: Pineapple is now the third most important tropical fruit in world production after banana and citrus. Phytosanitary irradiation is recognized as a promising alternative treatment to chemical fumigation. However, most of the phytosanitary irradiation studies have dealt with physiochemical properties and its efficacy. Accurate dose calculation is crucial for ensuring proper process control in phytosanitary irradiation. The objective of this study was to optimize phytosanitary irradiation treatment of pineapple in various radiation sources using Monte Carlo simulation. Methods: 3-D geometry and component densities of the pineapple, extracted from CT scan data, were entered into a radiation transport Monte Carlo code (MCNP5) to obtain simulated dose distribution. Radiation energy used for simulation were 2 MeV (low-energy) and 10 MeV (high-energy) for electron beams, 1.25 MeV for gamma-rays, and 5 MeV for X-rays. Results: For low-energy electron beam simulation, electrons penetrated up to 0.75 cm from the pineapple skin, which is good for controlling insect eggs laid just below the fruit surface. For high-energy electron beam simulation, electrons penetrated up to 4.5 cm and the irradiation area occupied 60.2% of the whole area at single-side irradiation and 90.6% at double-side irradiation. For a single-side only gamma- and X-ray source simulation, the entire pineapple was irradiated and dose uniformity ratios (Dmax/Dmin) were 2.23 and 2.19, respectively. Even though both sources had all greater penetrating capability, the X-ray treatment is safer and the gamma-ray treatment is more widely used due to their availability. Conclusions: These results are invaluable for optimizing phytosanitary irradiation treatment planning of pineapple.