• Structural Engineering and Mechanics
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• 제55권6호
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• pp.1177-1202
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• 2015

In this paper, a new intensity measure of earthquakes for probabilistic seismic analysis is presented for skewed highway bridges. Three different cases of skewed bridges with different skew angles ($0^{\circ}$, $30^{\circ}$ and $45^{\circ}$) are considered. Well-known intensity measures (e.g., PGA, $S_a$) are evaluated and critically discussed based on sensitivity analysis: efficiency, practically, proficiency and sufficiency of intensity measures are considered in detail. The analyses demonstrated that the intensity measures have to take into account structural acceleration on a wide range of periods so that a new seismic intensity measure is proposed showing that it has less dispersion compared to others. Since the proposed intensity represents the average value of the $S_a$ (between a lower and upper structural period) it has been called Averaged Spectral Acceleration (ASA). Based on performed incremental dynamic analysis (IDA), the seismic analytical fragility curves of typical skewed highway bridges have been evaluated for different states of damage controlling the low dispersion of the ASA index as well as its proficiency and sufficiency.

• Earthquakes and Structures
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• 제19권1호
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• pp.45-57
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• 2020

This paper presents the experimental application of a new method for seismic vulnerability assessment of buildings recently introduced in literature, the SMAV (Seismic Model Ambient Vibration) methodology with reference to their operational limit state. The importance of this kind of evaluation arises from the civil protection necessity that some buildings, considered strategic for seismic emergency management, should retain their functionality also after a destructive earthquake. They do not suffer such damage as to compromise the operation within a framework of assessment of the overall capacity of the urban system. To this end, for the characterization of their operational vulnerability, a Structural Operational Index (IOPS) has been considered. In particular, the dynamic environmental vibrations of the two considered strategic buildings, the fire station and the town hall building of a small town in the South of Italy, have been monitored by positioning accelerometers in well-defined points. These measurements were processed through modern Operational Modal Analysis techniques (OMA) in order to identify natural frequencies and modal shapes. Once these parameters have been determined, the structural operational efficiency index of the buildings has been determined evaluating the seismic vulnerability of the strategic structures analyzed. his study aimed to develop a model to accurately predict the acceleration of structural systems during an earthquake.

• Journal of Welding and Joining
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• 제20권6호
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• pp.30-30
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• 2002

It has been reported that the creep characteristics on weldment which is composed of weld metal(W.M), fusion line(F.L), heat-affected zone(HAZ), and base meta(B.M) could be unpredictably changed in severe service conditions such as high temperature and high pressure. However, the studies done on creep damage in power plant components have been mostly conducted on B.M and not the creep properties of the localized microstructures in weldment have been thoroughly investigated yet. In this paper, it is investigated the creep characteristics for three microstructures like coarse-grain HAZ(CGHAZ), W.M, and B.M in X20CrMoV121 steel weldment by the small punch-creep-(SP-Creep) test using miniaturized specimen(l0×10×0.5mm). The W.M microstructure possesses the higher creep resistance and shows lower creep strain rate than the B.M and CGHAZ. In the lower creep load the highest creep strain rate is exhibited in CGHAZ, whereas in the higher creep load the B.M represents the high creep strain rate. The power law correlation for all microstructures exists between creep rate and creep load at 600℃. The values of creep load index (n) based on creep strain rate for B.M, CGHAZ, and W.M are 7.54, 4.23, and 5.06, respectively and CGHAZ which shows coarse grains owing to high welding heat has the lowest creep loade index. In all creep loads, the creep life for W.M shows the highest value.

• Journal of Welding and Joining
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• 제20권6호
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• pp.754-761
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• 2002

It has been reported that the creep characteristics on weldment which is composed of weld metal(W.M), fusion line(F.L), heat-affected zone(HAZ), and base meta(B.M) could be unpredictably changed in severe service conditions such as high temperature and high pressure. However, the studies done on creep damage in power plant components have been mostly conducted on B.M and not the creep properties of the localized microstructures in weldment have been thoroughly investigated yet. In this paper, it is investigated the creep characteristics for three microstructures like coarse-grain HAZ(CGHAZ), W.M, and B.M in X20CrMoV121 steel weldment by the small punch-creep-(SP-Creep) test using miniaturized specimen($10{\times}10{\times}0.5mm$). The W.M microstructure possesses the higher creep resistance and shows lower creep strain rate than the B.M and CGHAZ. In the lower creep load the highest creep strain rate is exhibited in CGHAZ, whereas in the higher creep load the B.M represents the high creep strain rate. The power law correlation for all microstructures exists between creep rate and creep load at $600^{\circ}C$. The values of creep load index (n) based on creep strain rate for B.M, CGHAZ, and W.M are 7.54, 4.23, and 5.06, respectively and CGHAZ which shows coarse grains owing to high welding heat has the lowest creep loade index. In all creep loads, the creep life for W.M shows the highest value.

• Animal cells and systems
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• 제16권4호
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• pp.329-336
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• 2012

This study evaluated ecological health, using various biomarkers and bioindicators, of pale chub (Zacco platypus) as a sentinel species, in Daejeon Stream, South Korea, during AprilMay 2011. The biomarkers and bioindicators were compared among three sites of control: Reference ($C_z$), transition ($T_z$), and the urban zones ($U_z$); and the 7-Ethoxyresorufin-O-deethylase (EROD) activity, DNA damage, acetylcholinesterase (AChE) activity, and vitellogenin (VTG) concentrations were more significantly increased in the $U_z$ than in the $C_z$. Also, physiological markers such as condition factor, liver somatic index, visceral somatic index, and gonad somatic index were significantly increased in the $U_z$ than in the $C_z$. For the health assessments, three categorized parameters of blood chemistry, molecular biomarkers, and physiological bioindicators were standardized and calculated as a star-plot, representing values of Integrated Health Response (IHR). Values of IHR had more significant (P<0.05) increases in the $U_z$ than any other zones, indicating an impairment of ecological health by organic matter, nutrients (N, P), and toxic chemicals. This study is based on low levels of biological organization approach of molecular and physiological biomarkers and bioindicators, so further study of high-levels of biological organization approach such as community and population is required for overall range of health assessments. The approach of IHR values, however, may be useful in providing early warning of future impacts on ecological health.

• 대한방사선기술학회지:방사선기술과학
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• 제39권3호
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• pp.451-459
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• 2016

방사선 사고 및 방사선 치료 등 방사선에 의한 과피폭의 피해를 줄이기 위해 방사선방호제 개발연구는 활발히 진행되고 있다. 이에 화학적 합성물이 아닌 항산화, 항암, 면역 증강에 효과적인 것으로 알려진 백하수오를 이용하여 방사선방호효과를 확인하였다. 백하수오 에탄올추출물을 Sprague Dawley Rat (SD Rat)에 14일간 1일 1회 경구 투여하고, 7 Gy X-ray를 조사한 후 1일, 4일, 7일, 21일의 시간 변화에 따른 혈구성분, 비장 지수의 변화 및 간과 자궁의 조직변화를 관찰하였다. 실험결과 백하수오 에탄올추출물을 섭취한 실험군의 백혈구 수치(p < 0.05)와 비장 지수(p < 0.05)가 대조군보다 회복이 빠른 것을 확인하였다. 간 조직에서는 핵의 응축, 세포질의 팽창, 염증세포의 침윤이 감소하였으며, 자궁샘 조직은 세포고사가 감소한 것을 확인하였다. 위의 결과를 토대로 백하수오 에탄올추출물은 방사선 조사에 따른 혈구 및 장기의 피해를 줄일 수 있는 새로운 방사선방호제로써 유용할 것으로 기대되며, 방사선 사고와 같은 비상관리 분야에 적절한 시사점을 제공할 수 있다.

• Korean Chemical Engineering Research
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• 제58권3호
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• pp.438-449
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• 2020

본 연구는 화학 및 석유화학 플랜트 등의 장치산업에서 사업장 외부로 유해화학물질이 누출·확산되어 발생할 수 있는 배상책임 위험도에 대한 산정 방식을 개선하고자 하였다. 이를 위해 환경부 사고대비 물질(14종)에 대해 누출·확산 시뮬레이션, 화학물질 누출사고 사례 분석, 식물피해 영향 자료 분석 등을 통하여 화학물질 누출사고 배상책임 위험도와의 상관관계인자를 도출하였고, 도출된 결과를 바탕으로 화학물질 배상 책임 위험도 산정 방법을 수정·보완하였다. 14종의 화학물질의 Probit 값과 EURAM 배상책임 위험도의 상관계수는 -0.526로 나타났고, 수정된 화학물질 누출사고 배상책임 위험도와의 상관계수는 0.319로 상관성이 있는 것으로 분석되었다. 수정된 산정 방법론으로 97종에 대한 배상책임 위험도와 ERPG-2 값의 상관계수는 -0.494로 분석되었고, 이는 기존 배상책임 위험도와의 상관관계보다 약 19배 높은 상관관계를 보였고, 부식위험도 값과의 상관계수는 0.91로 분석되었다. 위험도의 증가와 감소에 영향을 미친 상관관계 인자의 표준화 회귀계수(β) 값은 Corrosion Index (0.713), ERPG-2 (0.400), NFPA_Health Index (0.068) 크기 순서로 도출되었다. 이러한 연구결과는 기존과 신규 화학물질의 합리적인 배상책임 위험도 산정이 가능하게 하고, 사업장에서 정량적인 배상책임 위험관리 지표로 활용하는데 도움이 되리라 판단된다.

• 한국수자원학회논문집
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• 제56권10호
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• pp.619-629
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• 2023

최근 기후변화가 심화됨에 따라 가뭄으로 유발되는 피해가 증가하고 있다. 현재 국내의 가뭄 강도를 결정하기 위해 표준강수지수(Standardized Precipitation Index, SPI)를 기준으로 분류를 수행하고 있다. 현재 국내에서는 최근 6개월 동안의 누적강수량을 기준(SPI-6)으로 관심, 주의, 경계, 심각의 기상학적 가뭄의 강도를 분류하고 있다. 그러나 강수량만을 기초자료로 활용하기 때문에 가뭄 강도를 분류하는 데 한계가 있다는 문제점이 있다. 따라서 본 연구에서는 SPI에 따른 국내 기상학적 가뭄 예･경보 기준의 한계점을 극복하고자 국가가뭄정보포털(National Drought Information Portal, NDIP)에서 제공하는 비상급수 피해자료를 수집하여 가뭄의 강도를 분류하였다. 그리고 SPI의 인자인 강수량과 증발산량 산정에 사용되는 인자인 온도, 습도 등을 min-max 정규화로 지수화한 후 유전 알고리즘(Genetic Algorithm, GA) 기반으로 각 인자들에 대한 계수를 산정하였다. 비상급수에 따른 가뭄의 강도를 분류하여 종속변수로 활용하고, GA에 의한 각 기상인자들의 계수를 활용하여 새로운 가뭄 강도 분류 지수(Drought Severity Classification Index, DSCI)를 도출하고자 하였다. DSCI를 도출한 후 누적분포함수를 활용하여 분위별 경계를 강도 단계 분류 기준으로 제시하였다. 본 연구에서 제시한 DSCI를 활용하면 기존 SPI보다 가뭄 강도를 정확하게 분류할 수 있어, 재난 담당자들의 의사결정을 지원할 수 있을 것으로 판단된다.

• 대한한방내과학회지
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• 제19권1호
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• pp.22-38
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• 1998

This study was to investigate the hepatoprotective and anticirrhotic effects of Ganyeumilhobang(GIE) on the acute and chronic liver injury induced by various agents. Chronic liver injury induced by dimethylnitrosamine(DMN) ; a new experimental model for cirrhosis and the intraperitoneal injection of dimethylnitrosamine in the rat. Acute liver njury induced by carbon tetrachloride$(CCl_4)$ and D-galactosamine ; a experimental model for acute liver injury, the administration of $CCl_4$ and the intraperitoneal injection of D-galactosamine in the rat. The development of fibrosis and acute liver injury by the three prescriptions were examined by the chemical analysis of AST, ALT, prothrombin time and hydroxyproline. The results obtained were as follows. 1. The increasing level of hydroxyproline volume induced by DMN in mice was decreased by the oral administration of GIB. 2. The degree of histological fibrosis and hepatic inflammatory cell infiltration induced by $CCl_4$ decreased by the oral administration of GIB. 3. The increase of senun AST and ALT of mice with acute liver damage induced by $CCl_4$ and D-galactosamine was inhibited by the administration of GIB. 4. The prolongation of prothrombin time(seconds) of mice acute liver damage induced by $CCl_4$ was shortened by the oral administration of GIB. 5. The liver of mice was hepatectomized partial1y after the oral administration of GIB. The mitotic index(% of nuclei), weight of liver, contents of protein, RNA and DNA synthesis of the liver tissue were increased by the oral administration of GIB.

• 한국기후변화학회지
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• 제8권2호
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• pp.171-175
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• 2017

The purpose of the farmstead-specific early warning service system for weather risk management is to develop custom-made risk management recommendations for individual farms threatened by climate change and its variability. This system quantifies weather conditions into a "weather risk index" that is customized to crop and its growth stage. When the risk reaches the stage where it can cause any damage to the crops, the system is activated and the corresponding warning messages are delivered to the farmer's mobile phone. The messages are sent with proper recommendations that farmers can utilize to protect their crops against potential damage. Currently, the technology necessary to make the warning system more practical has been developed, including technology for forecasting real-time weather conditions, scaling down of weather data to the individual farm level and risk assessments of specific crops. Furthermore, the scientific know-how has already been integrated into a web-based warning system (http://new.agmet.kr). The system is provided to volunteer farmers with direct, one-on-one weather data and disaster warnings along with relevant recommendations. In 2016, an operational system was established in a rural catchment ($1,500km^2$) in the Seomjin river basin.