• 한국지진공학회논문집
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• 제20권5호
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• pp.319-329
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• 2016

The Eradi Quake System (EQS) is a seismic isolation bearing system designed to minimize forces and displacements experienced by structures subjected to ground motion. The EQS dissipates seismic energy through friction of Poly Tetra Fluoro Ethylene (PTFE) disk pad. In general, a force-displacement relationship of EQS has post yield stiffness hardening during large inelastic displacement. In this study, seismic responses of seismically isolated nuclear power plant (NPP) subjected to design basis earthquake (DBE) and beyond design basis earthquakes (150% DBE and 167% DBE) are compared considering the post yield stiffness hardening effect of EQS. From the results, it can be observed that if the post-yield stiffness hardening effect of EQS is increased, the displacement response of EQS is reduced, and the acceleration and shear responses of containment structures of NPP is increased.

• 한국지진공학회논문집
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• 제17권2호
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• pp.61-70
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• 2013

An application of the EQS (Eradi Quake System) bearings to a short period building structure and the structure earthquake responses according to the design parameters of the EQS are studied by the ICT Center case study. The features of the EQS application to seismic isolated building structures are investigated, and the design procedure to determine the yield load and the secondary stiffness of the EQS is also studied. A computational analysis is performed to confirm the applicability of the EQS to the building structure and the earthquake responses according to the design parameters. The ICT Center in Indonesia is adopted as an application case of the EQS. The application of the EQS is found to extend the fundamental period of the ICT Center. Three types of EQS with different yield loads and secondary stiffness are designed and applied in the earthquake response analyses. The analysis results show the response of the structure with respect to the design parameters and which type of EQS is suitable for the ICT Center.

• 한국지진공학회논문집
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• 제19권1호
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• pp.13-19
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• 2015

This paper presents the performance improvement of an EQS (Eradic Quake System) device applied to a nuclear power plant. For the nuclear facility, the EQS device needs to be ensured to have high quality, flexibility of design and reliability. To improve the reliability of the design, the hysteresis of the device must be exactly predicted. The friction coefficient of PTFE (PolyTetraFluoroEthylene) and the stiffness of the MER-Spring are considered as the factors influencing the hysteresis curve. In this paper, those factors are analysed to predict the behavior of the device and to improve the equipment of the EQS device. The results of the improved EQS device have been verified via a tests to be comparable with the predicted results. The estimation results indicate that considering those factors is more appropriate than the results of the previous design and method.

• 한국철도학회논문집
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• 제8권3호
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• pp.276-285
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• 2005

This study discussed the effect on rail's axial force due to thermal and seismic loads according to supporting conditions of railway bridges; the considered supporting conditions are 1)simply supported, 2)roller at both ends, and 3)roller with horizontal spring at both ends. Closed form solutions are used to calculate the axial farces on rails. The roller at both ends of a bridge span decreases the compressive axial force on rail due to thermal load compared with the simply supported condition. However, the lateral springs at roller are not helpful to decrease the rail's compressive axial force.

• Asian Journal of Atmospheric Environment
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• 제7권4호
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• pp.177-190
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• 2013

Air pollution trends in Japan between 1970 and 2012 were analyzed, and the impact of air pollution countermeasures was evaluated. Concentrations of CO decreased from 1970 to 2012, and in 2012, the Japanese environmental quality standard (EQS) for CO was satisfied. Concentrations of $SO_2$ dropped markedly in the 1970s, owing to use of desulfurization technologies and low-sulfur heavy oil. Major reductions in the sulfur content of diesel fuel in the 1990s resulted in further decreases of $SO_2$ levels. In 2012, the EQS for $SO_2$ was satisfied at most air quality monitoring stations. Concentrations of $NO_2$ decreased from 1970 to 1985, but increased from 1985 to 1995. After 1995, $NO_2$ concentrations decreased, especially after 2006. In 2012, the EQS for $NO_2$ was satisfied at most air quality monitoring stations, except those alongside roads. The annual mean for the daily maximum concentrations of photochemical oxidants (OX) increased from 1980 to 2010, but after 2006, the $98^{th}$ percentile values of the OX concentrations decreased. In 2012, the EQS for OX was not satisfied at most air quality monitoring stations. Non-methane hydrocarbon (NMHC) concentrations generally decreased from 1976 to 2012. In 2011, NMHC concentrations near roads and in the general environment were nearly the same. The concentration of suspended particulate matter (SPM) generally decreased. In 2011, the EQS for SPM was satisfied at 69.2% of ambient air monitoring stations, and 72.9% of roadside air-monitoring stations. Impacts from mineral dust from continental Asia were especially pronounced in the western part of Japan in spring, and year-round variation was large. The concentration of $PM_{2.5}$ generally decreased, but the EQS for $PM_{2.5}$ is still not satisfied. The air pollution trends were closely synchronized with promulgation of regulations designed to limit pollutant emissions. Trans-boundary OX and $PM_{2.5}$ has become a big issue which contains global warming chemical species such as ozone and black carbon (so called SLCP: Short Lived Climate Pollutants). Cobeneficial reduction approach for these pollutants will be important to improve both in regional and global atmospheric environmental conditions.

• 한국약용작물학회지
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• 제18권4호
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• pp.224-230
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• 2010

This study was conducted to investigate anti-oxidative and inflammatory inhibition effects of green tea and dietary fiber mixture on liver of high fat diet-induced obese rats. 21 male rats were divided into 3 dietary groups and control group (A), high fat diet-induced group (B), and high fat (HF) diet-induced + EQ diet-$S^{(R)}$ diet group (C). Immunoblotting and RT-PCR analysis revealed protein expression, and anti-oxidant analysis revealed MDA (malondialdehyde), GSH (glutathione), and free DPPH radical. As a results, Body weight and food consumption were not significantly different between groups. The levels of MDA and GSH were lower in HF + $EQS^{(R)}$ group than in HF group. Also, the $EQS^{(R)}$ demonstrated to be more effective than HF group for a DPPH radicals scavenging activities. In addition, protein and mRNA level of TNF-$\alpha$ in HF + $EQS^{(R)}$ group showed relatively more potent pro-inflammatory activity inhibition compared to HF group. These results suggest that green tea mixture (EQ diet-$S^{(R)}$) provide positive effects on anti-oxidative and inflammatory inhibition effects on obese animal model or obesity related diseases.

• 한국조경학회지
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• 제38권5_2호
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• pp.151-162
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• 2010

This research aimed at measuring Park and Green Satisfaction (PGS) using subjective indicators of 'surface, line and spot' green evaluated by citizens. Also frequency of visits to park and green measured using objective indicators (number of visits) to find the relationship with PGS. A conceptual model of PGS was developed to relate evaluation to satisfaction and finally to utilization of open spaces. A sample of 500 questionnaire survey was employed for Uijeongbu City in Korea. A Structual Equation Modeling (AMOS) techniques was used to test the hypothesized relationship among factors (construct). As a result, first, PGS was explained by three latent factors of 'urban park' (${\gamma}=0.54$), 'linear facilities' (${\gamma}=0.25$), and 'surface green' (${\gamma}=0.15$) respectively. These three exogenous construct was found very useful classification system for open spaces of cities. Second, PGS (${\gamma}=0.34$) was found as a mediating variable to utilization of open spaces and also PGS was closely related to citizens Environmental Quality Satisfaction (EQS), such concept as, 'livability' and 'aesthetic quality'. The more satisfied with park and green the more people use the space. The PGS was an important QOL indicator together with the subjective indicator of 'livability'. Third, jogging and walking trails and bike ways along the river corridor was the most important green facilities contribute to the PGS and EQS. The near the distance (within 500m) the more number of visit to river corridor (green way). The river corridor promote accessibility to nature and other parks.

• Structural Engineering and Mechanics
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• 제7권3호
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• pp.303-318
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• 1999

Cracking of reinforced concrete flexural members is a highly random phenomenon. In this paper reliability models are presented to determine the probabilities of failure of flexural members against the limit states of first crack and maximum crackwidth. The models proposed take into account the mechanism of cracking. Based on the reliability models discussed, Eqs. (8) and (9) useful in the reliability-based design of flexural members are presented.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.249-253
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• 2005

The turbulence noise generated from blunt trailing-edge is numerically predicted by using the hydrodynamic/acoustic splitting method at the Reynolds number based on thickness of flat plate, $Re_h=1000$, and the freestream Mach number $M_o=0.2$. The turbulent flow field is simulated by incompressible large-eddy simulation and the acoustic field is predicted efficiently with the linearized perturbed compressible equations (LPCE) recently proposed by the authors. The turbulent flow characteristics are validated with the results of the previous experimental study and direct numerical simulation. The acoustic properties predicted from LPCE are compared with the solutions of analytical formulations.

• 한국수자원학회논문집
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• 제39권5호
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• pp.405-415
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• 2006

건조기 때의 합류식 관거 내 고형물의 퇴적으로 인해 통수능이 감소하여 여름철 장마시 국지적인 침수가 발생하며 이로 인해 관거 내 퇴적을 더욱 초래할 수가 있다. 또한 관거 시스템에 퇴적된 고형물로 인해 우기시 'first-flush' 현상을 초래하기도 한다. 이와 같은 문제를 해결하기 위해서는 장기간에 걸친 관거 내 고형물 퇴적량을 관측할 필요가 있으나 많은 비용과 노력이 수반되어야 한다. 따라서 본 연구에서는 미국환경보호청에서 개발한 건조기의 합류관거 내 고형물 퇴적량 산정기법을 우리나라의 배수유역에 적용하여 분석하였다. 분석결과 적용 배수유역의 가용 자료에 따라 모형을 선택하여 실무에서 간편하게 적용할 수가 있지만 모형별 변수산정 방법별로 많은 차이를 보이고 있다. 초기에 유도된 Eqs. (1)$\sim$(4)가 후에 유도된 Eqs. (5)$\sim$(9)보다 산정치가 모두 크게 나타나고 있으며 전반적으로 중간모형이 정밀모형이나 단순모형보다 크게 나타나고 있다. 건조기 동안의 관거 내 퇴적고형물의 관측자료가 구비되어 있지 않아 실질적으로 비교하기가 곤란하지만 대상 배수유역 관거에서의 장기적인 관측이 이루어지고 이에 따라 국내실정에 맞도록 산정공식의 수정이 이루어지면 실무에서 많은 비용과 노력을 줄이고 관거 관리를 할 수 있다고 판단된다.