• Title/Summary/Keyword: Natural radiation

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Heat Transfer Analysis around Transport Cask under Transport Hood (사용후핵연료 운반용기 덮개 내부 열전달 해석)

  • Lee, Dong-Gyu;Park, Jae-Ho;Jung, In-Su;Kim, Tae-Man;Yoon, Jeong-Hyun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.3
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    • pp.161-167
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    • 2011
  • In case that the maximum temperature of any surface readily accessible during transport of a spent nuclear fuel (SNF) transport cask exceeds $85^{\circ}C$ in the absence of insolation under the ambient temperature of $38^{\circ}C$, personnel barriers or transport hood shall be used to prevent people from casual contact with the transport cask surface. Usually the air temperature within the hood and the hood surface temperature are calculated and further utilized as boundary conditions(free stream temperature and external radiation temperature) for thermal evaluation under normal conditions of transport. In this study, these temperatures are derived using the analytical method based on the heat transfer mechanism around the transport cask under transport hood assuming the thermal equilibrium. By comparing the analytical solutions with the results from the detailed calculations with CFD-computer-code FLUENT 12.1 it is verified that the analytical method is still efficient tool to estimate the temperatures and these temperatures can be further used as boundary conditions for thermal evaluation under normal conditions of transport.

A Study on the Assessment of Source-term for PWR Primary System Using MonteCarlo Code (MonteCarlo 코드를 이용한 PWR 일차 계통 선원항 평가에 관한 연구)

  • Song, Jong Soon;Lee, Sang Heon;Shin, Seung Su
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.16 no.3
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    • pp.331-337
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    • 2018
  • The decommissioning of nuclear power plants is generally executed in five steps, including preparation, decontamination, cutting/demolition, waste disposal and environmental restoration. So, for efficient decommissioning of nuclear power plants, worker safety, effects compared to cost, minimization of waste, possibility of reuse, etc., shall be considered. Worker safety and measurement technology shall be secured to exert optimal efficiency of nuclear power plant decommissioning work, for which accurate measurement technology for systems and devices is necessary. Typical In-Situ methods for decommissioning of nuclear plants are CZT, Gamma Camera and ISOCS. This study used ISOCS, which can be applied during the decommissioning of a nuclear power plant site without collecting representative samples, to take measurements of the S/G Water Chamber. To validate the measurement values, Microshield and the GEANT4 code was used as the actual method were used for modeling, respectively. The comparison showed a difference of $1.0{\times}10^1Bq$, which indicates that it will be possible to reduce errors due to the influence of radiation in the natural environment and the precision of modeling. Based on the research results of this paper, accuracy and reliability of measurement values will be analyzed and the applicability of the direct measurement method during the decommissioning of NPPs will be assessed.

Wild Boar (Sus scrofa corranus Heude ) Habitat Modeling Using GIS and Logistic Regression (GIS와 로지스틱 회귀분석을 이용한 멧돼지 서식지 모형 개발)

  • 서창완;박종화
    • Spatial Information Research
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    • v.8 no.1
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    • pp.85-99
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    • 2000
  • Accurate information on habitat distribution of protected fauna is essential for the habitat management of Korea, a country with very high development pressure. The objectives of this study were to develop a habitat suitability model of wild boar based on GIS and logistic regression, and to create habitat distribution map, and to prepare the basis for habitat management of our country s endangered and protected species. The modeling process of this restudyarch had following three steps. First, GIS database of environmental factors related to use and availability of wild boar habitat were built. Wild boar locations were collected by Radio-Telemetry and GPS. Second, environmental factors affecting the habitat use and availability of wild boars were identified through chi-square test. Third, habitat suitability model based on logistic regression were developed, and the validity of the model was tested. Finally , habitat assessment map was created by utilizing a rule-based approach. The results of the study were as folos. First , distinct difference in wild boar habitat use by season and habitat types were found, however, no difference in wild boar habiat use by season and habitat types were found , however, ho difference by sex and activity types were found. Second, it was found, through habitat availability analysis, that elevation , aspect , forest type, and forest age were significant natural environmental factors affecting wild boar hatibate selection, but the effects of slope, ridge/valley, water, and solar radiation could not be identified, Finally, the habitat at cutoff value of 0.5. The model validation showed that inside validation site had the classification accuracy of 73.07% for total habitat and 80.00% for cover habitat , and outside validation site had the classification accuracy of 75.00% for total habitat.

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Anti-Inflammatory Effect of Ixeris dentata on Ultraviolet B-Induced HaCaT Keratinocytes

  • Kim, Sung-Bae;Kang, Ok-Hwa;Keum, Joon-Ho;Mun, Su-Hyun;An, Hyun-Jin;Jung, Hyun-Ju;Hong, Seung-Heon;Jeong, Dong-Myong;Kweon, Kee-Tae;Kwon, Dong-Yeul
    • Natural Product Sciences
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    • v.18 no.1
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    • pp.60-66
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    • 2012
  • Human skin is the first line of defense for the protection of the internal organs of the body from different stimuli. Ultraviolet B (UVB) irradiation induces skin damage and inflammation through the secretion of various cytokines, which are immune regulators produced by cells. To prevent the initiation of skin inflammation, keratinocytes that have been irreversibly damaged by radiation must be removed through the apoptotic mechanism. Ixeris dentata (family: Asteraceae) is a perennial medicinal herb indigenous to Korea. It has been used in Korea, China, and Japan to treat in digestion, pneumonia, diabetes, hepatitis, and tumors. To gain insight into the anti-inflammatory effects of I. dentata, we examined its influence on UVB-induced pro-inflammatory cytokine production in human keratinocytes (HaCaT cells), by observing cells that were stimulated with UVB in the presence or absence of I. dentata. In the present study, pro-inflammatory cytokine production was determined by performing enzyme-linked immunosorbent assay, reverse transcription polymerase chain reaction, and western blot analysis to measure the activation of mitogen-activated protein kinase (MAPKs). I. dentata inhibited UVBinduced production of the pro-inflammatory cytokine interleukin (IL)-6 in a dose-dependent manner. Further, I. dentata inhibited the UVB-induced expression of cyclooxygenase (COX)-2. Furthermore, I. dentata inhibited the phosphorylation of c-Jun NH2-terminal kinase and p38 MAPKs, suggesting that it inhibits the secretion of the pro-inflammatory cytokines IL-6 and IL-8, and COX-2 expression, by blocking MAPK phosphorylation. These results suggest that I. dentate can potentially protect against UVB-induced skin inflammation.

Compositional Changes of Kochujang During Fermentation in Onggis with Different Physical Properties (물리적 특성이 다른 옹기에서의 고추장 발효 중 성분 변화)

  • Chung, Sun-Kyung;Lee, Kwang-Soo;Lee, Dong-Sun;Lee, Se-Hoon
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.13 no.2
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    • pp.51-58
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    • 2007
  • This research investigated the effect of different onggi containers (Korean earthenware) on the ripening of kochujang (Korean hot pepper paste). The physical characteristics of 'onggi', were evaluated as function of manufacturing variables such as raw material soils (onggi-specific soil, red brown soil, and fine powdered soil) and galzing treatments. The physical properties were then related to the compositional quality changes of the kochujang fermented at $30^{\circ}C$ for 4 months. The porosity of the onggi containers seems to be increased by the content of finer raw soil rather than the chemical component of soil (amount of CaO, MgO, $K_2O$ and $Na_2O$, acting as melting aid in the firing). Natural glaze was measured to contain higher contents of CaO, MgO, $K_2O$ and $Na_2O$ than the other soils, which is desirable property for the fired onggi. The glazed surface showed higher far-infrared radiation emissivity than the non-glazed part. The kochujang fermented in P0-BG (the glazed onggi from 100 % onggi soil) attained higher concentration of reducing sugar, amino nitrogen and nucleotides compared to those in the other onggis. All of these changes of kochujang in P0-BG resulted in significantly better sensory quality than the other treatments.

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Anti-oxidative Activities of Angelica dahurica Radix Ethanol Extract (백지 에탄올추출물의 항산화 활성에 관한 연구)

  • Kim, Pil-Sun;Lee, Tae-Jong;Kim, Yang-Hee;Kim, Jung-Si
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4378-4384
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    • 2011
  • In order to evaluate the anti-oxidative capabilities of Angelica dahurica Radix ethanol extract (ADEE), we analyzed the contents of polyphenol and flavonoid compounds and the electron donating ability from ADEE. For animal experimentation, the test agent was topically applied to the artificial tanning spots which were induced by 1,500 mJ/$cm^2$ of ultraviolet B radiation on the backs of brown guinea pigs weighing approximately 450~500g. The test agent of $30{\mu}{\ell}$ was applied (6areas per group) twice a day, five days a week, for five weeks. On completion of the experiment, the animals were sacrificed under anesthetization, and the artificial tanning spots were obtained by biopsy punch and stained with H&E to observe the histological change in the epidermis and dermis. As a result, the contents of polyphenol and flavonoid compounds in ADEE were 20.7mg/g and 19.5mg/g respectively. As the for electron-donating capability of ADEE, it was observed that ADEE displays a dose-dependent antioxidative capacity of 14.8% and 19.8% at the concentration of 500 and 1000 ${\mu}g/m{\ell}$ respectively. Tissue staining with H&E revealed that the epidermis of the control group was slightly thicker than that of the other groups. However no inflammation or any other undesirable effect on the skin tissue due to ADEE was observed. These results indicate that ADEE is of value as a natural antioxidant.

A Study of the Improvement Plan and Real Condition Estimation of Fire Protection Safety Management for Power Plants in Korea (국내발전소 소방안전관리 운영실태조사 및 개선방안에 관한 연구)

  • Kang, Gil-Soo;Choi, Jae-wook
    • Fire Science and Engineering
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    • v.31 no.2
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    • pp.61-73
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    • 2017
  • The Fukushima Nuclear Disaster in 2011 and California Power Failure in 2001 are examples of the importance of the power plant safety management that caused huge national loss with a power-related mass casualty incident. In a situation where humans cannot live without electricity, efforts to strengthen the systematic firefighting safety management in power plants that produce electricity with large amounts of hazardous materials as fuel, such as nuclear energy, coal and gas, are essential to protect life and prevent property loss and stable economic growth from fire explosion accident or radiation leak due to the negligence of safety management and natural disasters such as earthquakes, which has recently become an issue. This study examined the operating situation of firefighting safety management in power plants with firefighting officials employed by five power generation companies including Korea Southern Power Co., Ltd. and Korea Hydro & Nuclear Power Co. Ltd., which are in charge of the domestic power supply. As a result, for the systematic firefighting safety management of power plants, improvement plans were drawn, including the development of an effective business manual and a comprehensive management system, the substantiality of firefighting safety education, and the strengthening of seismic designs to prepare for earthquakes.

An Experimental Study for Dryer (건조기 고안 제작에 관한 연구)

  • 최재갑
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.1
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    • pp.3677-3684
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    • 1975
  • A newly devised dryer with heated air for the farm products, especially suited for high water content materials such as red pepper, Beer ground, each Vegetables, and Low water content materials such as Rough rice was tested for its thermal efficiency and drying mechanism, and the optimum conditions for each sample were established. In order to improve the present rural situation of drying farm products which entirely dependent upon natural solar radiation, a study upon an economic multi-parpose dryer was conducted. A series of drying tests were run first with red pepper which is one of the important cash crop in Korean farm. And successive series of tests were also run with such proaucts as garlic, sweet potatoes, green onion, radish, Beer ground and Rough rice. The results from the above experiment in drying system with heat dryer can be summarized as follows. 1. Drying duration could be shortened by the tempering effect in high water content crop such as red pepper and beer ground. 2. The color changes occured in around 20% water content in red pepper. The degree of color change was heavily affected by high temperature and short drying duration. 3. The drying condition of red pepper was most favourable at the temperature of 85$^{\circ}C$ in early stage and 80$^{\circ}C$ in middle stage and 75$^{\circ}C$ at the final stage, and with the air rate of 0.81㎥/sec and with sample amount of 200kg. 4. The drying condition of Rough rice(I.R.667) was most favourable at the templature of 40$^{\circ}C$ in early stage and 35$^{\circ}C$ in middle stage and final stage and with the air rate of 0.2㎥/sec and with sample amount of 75kg. 5. In order to prevent the color change of red pepper and to assure high efficiency in drying mechanism, it was necessary to lower the temperature as the time passes in drying process. 6. For vege tables, the drying rate were short in early stage and there was also tempering effect. However, for garlics, Constant drying rates through the early and final stages were observed and there were no tempering effects. 7. The drying condition or capability were as follows; Sample drying temp($^{\circ}C$) amount of material(kg) drying time(hr) Red pepper 85 200 9 Garlic 85 150 7 Sweet potato 85 200 6 Green Onion 85 200 4 Carrot 85 200 4 Radish 90 250 4 Rough rice(I.R.667) 35 75 4 Beer ground 90 320 3 Considering the above result of experiments, if this kind of dryers were distributed Korean farm and the optimun process were practiced in rural area, it would certainly help them improving the qualites of their product preventing their undue losses, and thus assuring an increase of Korean farm income and promotion of their living standards.

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Correlation Analysis of Meteorological Factors for Wooden Building in Beopjusa and Seonamsa Temples by Statistical Model (통계적 모형을 통한 법주사와 선암사 목조건축물의 기상인자에 대한 상관성 분석)

  • Kim, Young Hee;Kim, Myoung Nam;Lim, Bo A;Lee, Jeung Min;Park, Ji Hee
    • Journal of Conservation Science
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    • v.34 no.5
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    • pp.387-396
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    • 2018
  • Exposure to the natural environment can cause damage to domestic wooden cultural assets, such as temples. Deterioration is accelerated by biological damage and various environmental factors. In this study, meteorological factors were monitored by equipment installed at Beopjusa temple of Boeun province and Seonamsa temple of Suncheon province. A statistical model was applied to these data to predict the meteorological factors and to compare the predictive performance of each meteorological factor. The resulting correlation coefficient between air and dew point temperatures was highest, at 0.95, while the correlation coefficient for relative humidity had a moderate value(0.65) at both the Beopjusa and Seonamsa temples. Thus, a general linear model was found to be suitable for predicting air and dew point temperatures. An analysis of correlation between meteorological factors showed that there was strong positive correlation between air temperature and dew point temperature, and between solar radiation and evaporation at both sites. There was a weak positive correlation between air temperature and evaporation at Beopjusa temple. Wind speed was negatively correlated with both air temperature and relative humidity at Seonamsa temple. The wind speed at this location is higher than average in winter and lower than average in summer, and it was hypothesized that the low wind speed plays a role in reducing water evaporation in summer, when both air temperature and relative humidity are high. As a result, damage to the wooden buildings of Seonamsa temple is accelerated.

Inhibitory effect of Aralia elata ethanol extract against skin damage in UVB-exposed human keratinocytes and human dermal fibroblasts (두릅순 에탄올 추출물의 인간유래 피부각질형성세포와 피부섬유아세포에서의 자외선에 의한 광노화 억제효과)

  • Yang, Jiwon;Kwak, Chungshil
    • Journal of Nutrition and Health
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    • v.49 no.6
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    • pp.429-436
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    • 2016
  • Purpose: Solar ultraviolet (UV) radiation causes inflammation and matrix metalloproteinase (MMP) overexpression and extracellular matrix depletion, leading to skin photoaging such as wrinkle formation, dryness, and sagging. Activation of MMP is influenced by various molecules such as reactive oxygen species (ROS), proinflammatory cytokines, and transient receptor potential vanilloid type (TRPV)-1, which are increased in UV-irradiated skin cells. Aralia elata (AE) ethanolic extract was reported to inhibit ROS generation caused by UVB-irradiation in keratinocytes. In this study, we investigated the photoprotective effect of AE ethanolic extract on UVB-irradiated human keratinocytes (HaCaT) and human dermal fibroblasts (HDF). Methods: AE was freeze-dried, extracted in 70% ethanol, and concentrated. Skin cells were treated with AE extract for 24 h and then exposed to UVB ($55mJ/cm^2$). After 48 h of incubation, proinflammatory cytokines, MMP-1, type-1 procollagen, and TRPV-1 levels were measured by ELISA or Western blotting. Results: Treatment with AE extract ($100{\mu}g/mL$) significantly inhibited UVB-induced IL-6, IL-8, and $PGE_2$ production in HaCaT by 25.6%, 5.3%, and 70.2%, respectively, and also inhibited elevation of MMP-1 and TRPV-1 caused by UVB irradiation by 20.0% and 41.9%, respectively (p < 0.05). In HDF, AE extract treatment significantly inhibited both elevation of MMP-1 and reduction of type-1 procollagen caused by UVB irradiation (p < 0.05). In addition, type-1 procollagen was elevated by AE extract treatment in normal HDFs (p < 0.05). Conclusion: AE 70% ethanol extract has photoprotective ability via reduction of proinflammatory mediators, TRPV-1 and MMP-1 production, and elevation of collagen synthesis. Our findings suggest that AE extract might be a good natural material to protect against UVB-induced premature skin aging.