• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2828-2834
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• 2024

This research intends to recycle bone and incorporate it into concrete for radiation shielding application using Phy-X/PSD software. Cement, sand and granite were mixed in proportion of 0.5 kg:1 kg:1 kg to obtain sample A. Other concretes composing of cement, sand, granite and bone ash was in proportion 0.45 kg:1 kg:1 kg:0.05 kg, 0.1 kg:1 kg:1 kg:0.4 kg and 0.35 kg:1 kg:1 kg:0.15 kg to obtain samples B, C and D respectively. 0.5 water-to-cement (W/C) ratio was adopted throughout the mixes because the control mix contain the normal water quantity for normal hydration of cement. Replacing the bone ash for the cement in the fabricated concretes enhances their densities where the fabricated concretes' density decreased from 2.33 g/cm³ to 2.22 g/cm³ by raising the reinforcing bones fly ash concentration from 0 to 0.15 kg. Additionally, increasing the bones fly ash concentration within the fabricated concretes increases their linear attenuation coefficient (LAC) where the fabricated concretes' μ values at 0.662 MeV reach 0.181 cm^-1, 0.178 cm^-1, 0.174 cm^-1, and 0.171 cm^-1, respectively for concretes A, B, C, and D. The use of other local materials is recommended, as it improves waste management being the major aim of the sustainable development goal.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.635-642
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• 2020

The purpose of this study was to analysis the effects of shielding area of field configuration with changing of sensitivity and density on tube current (milliampere-seconds, mAs) and image quality in automatic exposure control (AEC) system. The equipment used a digital radiography device (Digital Diagnost, Philips, Netherlands), which has a integral type with an X-ray tube and an indirect digital detector. The AEC system conditions were consisted of 9 setting environments, that mode changing of the sensitivity (S200, S400, S800) and the density (+2.5, 0, -2.5). The tube current evaluated automatically exposed mAs under 81 combination conditions crossed by AEC conditions in fixed at 40 kVp. The image quality evaluated the radiographic images that selected valid images by visual assessment the radiographic images of the self-produced conical pyramid phantom and then measured their signal to noise ratio (SNR). As a result, the maximum tube current was 60.0 mAs that automatically exposed conditions were the 100% of shielding area and the sensitivity of S200 and the density of +2.5. The minimum tube current was 0.9 mAs with non-shielding area and the sensitivity of S800 and the density of -2.5. When the shielded area 0% with the sensitivity of S200 and the density of +2.5, the maximum SNR was the highest as 25.2. But when the shielded area 25% with the sensitivity of S800 and the density of -2.5, the minimum SNR was the lowest as 4.7.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.295-298
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• 2013

Nano-size manganese ferrite reinforced conductive polypyrrole composites reveal a core-shell structure by in situ polymerization, in the presence of dodecyl benzene sulfonic acid as the surfactant and dopant, and iron chloride as the oxidant. The structure and magnetic properties of manganese ferrite nano-fillers were measured, by using X-ray diffraction and vibrating sample magnetometer. The morphology, microstructure, and conductivity of the composite were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and four-wire technique. The microwave-absorbing properties of composites reinforcement dispersed in resin coating with the coating thickness of 1.2 nm were investigated, by using vector network analyzers, in the frequency range of 8~12 GHz. A reflection loss of -8 dB was observed at 10.5 GHz.

• Journal of radiological science and technology
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• v.23 no.2
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• pp.69-73
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• 2000

This paper studied a C-arm's exposure condition and measured scatter rays by thickness and distance. This study reached the following conclusion. 1. Approrimately exposure dose for a patient using fluoroscopy is as follows : 2. Mostly, an operating room was not shielding by lead and operator put on only apron without thyroid and facial part protection. 3. 0.5 mmPb equivalent's apron shielded about 99% of scattered rays at 60 cm from x-ray tube. 4. Scattered rays are depended on distance and thickness so operators are should be careful when using fluoroscopy by C-arm and if possible use high frequency equipment that has a large output.

• Nuclear Engineering and Technology
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• v.28 no.3
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• pp.320-330
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• 1996

The streaming rays(SR) method is improved and extended to multigroup, anisotropic scattering, and three-dimensional angular space(x-y-z(infinite))problems. This method is applied to the shielding problems in which the ray effect occurs seriously. For verification, the results of MORSE-CG code are used as reference solution and the results of TWODANT code are compared. The results show that solutions of the SR method are much better than those of the TWODANT code and are in good agreement with those of the MORSE-CG code. Also, to reduce computing time, two acceleration algorithms are implemented in the SR method : the standard coarse-mesh rebalance and a new angular two-grid acceleration.

• Journal of the Korean Society of Radiology
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• v.14 no.7
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• pp.891-898
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• 2020

As the problem of shields made of lead has recently emerged, research on replacement shields is essential, and studies on the manufacture of diagnostic X-ray shields with 3D printers are also being actively conducted. Recently, with the development of metal mixed filaments, it has become possible to manufacture shielding materials easily, but studies on the nozzle size and output setting of 3D printers are insufficient. Therefore, this study aims to compare and analyze the results through a shielding rate experiment using a brass filament and a 3D printer, outputting the shield according to the nozzle size and layer height, and using a diagnostic radiation generator. The nozzle size was changed to 0.4, 0.8 mm, layer height 0.1, 0.2, 0.3, 0.4 mm, and output. The shielding rate test was fixed at 40 mAs, and the shielding rate was analyzed by experimenting with 60, 80, and 100 kVp, respectively. As a result of the analysis, it was analyzed that the printing time could be reduced to 1/10 according to the nozzle size and the layer height, and the shielding rate could be increased by 1% or more.

• Journal of radiological science and technology
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• v.47 no.3
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• pp.205-211
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• 2024

Currently, with the development of technologies, X-ray examinations for medical examinations at hospital is increasing. This study was conducted to help reduce radiation exposure by measuring the exposure dose received by pediatric patients and the spatial dose of the X-ray room. Dosimeters were installed in the eyeball, thyroid gland, breast, gonads and 4 directions at a distance of 30 cm, 40 cm, 50 cm from the phantom. The dose was measured ten times each, before, and after the application of the bismuth shield under the examination conditions of the head, chest, and abdomen of pediatric patients. Under the condition of head examination, when a shielding was applied, the dose reduction rate was 68.58% for the eyeball, 72.88% for the thyroid, 84.2% for the breast, and 72.36% for the gonad. The chest examination showed reductions of 19.56% eyeball, 56.98% thyroid, 1.21% breast, and 0.68% gonad. The abdominal examination showed reduction rates of 2.6% eyeball, 10.67% thyroid, 19.85% breast, and 82.02% gonad. Spatial dose decreased by 62.25% at 30 cm, 61.16% at 40 cm, and 68.68% at 50 cm. When the bismuth shield was applied, there was a decrease in dose across all examinations, as well as a reduction in spatial dose. Continued research on the use of bismuth shields will help radiological technologists achieve their goal of dose reduction.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.212-218
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• 2019

To investigate the effect of the oxyfluorination of carbon nanotubes (OF-CNTs) on electroless Ni deposition and electromagnetic interference shielding efficiency (EMI SE), CNTs were treated with a mixture of oxygen and fluorine gases and sequentially deposited with nickel. These samples were then manufactured into thin films on a polyimide film to evaluate their EMI SE. The surface chemical property of OF-CNTs was investigated by X-ray photoelectron spectroscopy. From the results of thermogravimetric and scanning electron microscopic analyses, it was found that both the amount of deposited Ni and the surface morphology changed depending on oxyfluorination. Moreover, the Ni-deposited CNTs pretreated with $O_2:F_2=1:9vol%$ exhibited the maximum EMI SE as approximately 19.4 dB at 1 GHz. These results were attributed to the formation of oxygen and fluorine functional groups on the surface of CNTs due to the oxyfluorination, and the functional groups enabled to deposit a suitable amount of Ni and improve the dispersion in the deposited solution.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.559-563
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• 2016

Recently, a barium(Ba) and an iodine(I) being studied as a conventional lead(Pb) alternatives of shielding material has excellent shieding rate, but the characteristic x-ray photons in the energy range near 30 keV line is released. In this study, with bismuth oxide(BiO) coupled barium sulfate($BaSO_4$) double layer, transmitted spectra, shieding rates and relative weighting rates were evaluated to validate the applicability of eco-friendly double layer shieding structure using monte carlo simulations as a prior study. From the evaluation results, in 0.4mm and 0.5mm thickness of BiO layers coupled with top 0.1mm-$BaSO_4$ layer, the shieding rate showed 1.9% and 3.9% higher than 0.6mm thickness of Pb single layer, respectively. In addition, the relative weight also 28% and 34.5% lower than 0.6mm-Pb in 0.4mm and 0.5mm thickness of BiO layers coupled with top 0.1mm-$BaSO_4$ layer.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.423-428
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• 2017

In this study, the calculation of the effective spatial dose distribution of the diagnostic imaging laboratory of K university was performed by the Monte Carlo simulation. The radiation generator has a maximum tube voltage of 150 kVp and a maximum current of 700 mA. Using the results, we compared the spatial effective dose distributions of diagnostic imaging laboratory when the shielding door was closed and opened. In conclusion, it was found that the effective dose in the operating room of the diagnostic imaging laboratory does not exceed the annual dose limit (6 mSv/y) of the student (occasional visitor) even when the door is opened. However, since the effective dose when the door is open is about 16 times higher in front of the lead glass window and about 3,000 times higher in front of the doorway than the case when the door is closed, closing the shielding door at the time of the practical exercising reduces unnecessary radiation exposure by great extent.