• Title/Summary/Keyword: site-response effect

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The Hyperthermic Effect of Nitric Oxide in Central Nervous System

  • Jung, Jae-Kyung;Sohn, Uy-Dong;Lee, Seok-Yong
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.1
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    • pp.93-98
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    • 2001
  • The precise mechanism of set-point regulation in hypothalamus was not elucidated. Nitric oxide synthases(NOS) were detected in hypothalamus, however, the roles of NO in hypothalamus was not fully studied. So, we tested the effects of NO on body temperature because preoptic-anterior hypothalamus was known as the presumptive primary fever-producing site. NO donor sodium nitroprusside (SNP, 4 nmol, i.c.v.) elicited marked febrile response, and this febrile response was completely blocked by indomethacin (a cyclooxygenase inhibitor). But, ODQ (selective guanylate cyclase inhibitor, $50\;{\mu}g,$ i.c.v.) did not inhibit fever induced by SNP. The cyclic GMP analogue dibutyryl-cGMP $(100\;{\mu}g,\;i.c.v.)$ induced significant pyreses, which is blocked by indomethacin. $N^G-nitro-L-arginine$ methyl ester (L-NAME, non selective NOS inhibitor) inhibited fever induced by $interleukin-1{\beta}\;(IL-1{\bata},\;10\;ng,\;i.c.v.),$ one of endogenous pyrogens. These results indicate that NO may have an important role, not related to stimulation of soluble guanylate cyclase, in the signal pathway of thermoregulation in hypothalamus.

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Reliability analysis of LNG unloading arm considering variability of wind load (풍하중의 변동성을 고려한 LNG 하역구조물의 신뢰성해석)

  • Kim, Dong Hyawn;Lim, Jong Kwon;Koh, Jae Pil
    • Journal of Korean Society of Steel Construction
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    • v.19 no.2
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    • pp.223-231
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    • 2007
  • Considering wind speed uncertainty, reliability analysis of the LNG unloading arm at Tongyoung Production Site was performed. Extreme distribution of wind speed was estimated from the data collected at the weather center and wind load was calculated using wind velocities and coefficients of wind pressure. The unloading arm was modeled with plate and solid elements. Contact elements were used to describe the interface between base of structure andground. Response surface for maximum effective stress was found for reliability analysis and then reliability functions was defined and used to determine exceeding probability of allowable and yield stresses. In addition, sensitivity analysis was also performed to estimate the effect of possible material deterioration in the future.

Effect of non-stationary spatially varying ground motions on the seismic responses of multi-support structures

  • Xu, Zhaoheng;Huang, Tian-Li;Bi, Kaiming
    • Structural Engineering and Mechanics
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    • v.82 no.3
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    • pp.325-341
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    • 2022
  • Previous major earthquakes indicated that the earthquake induced ground motions are typical non-stationary processes, which are non-stationary in both amplification and frequency. For the convenience of aseismic design and analysis, it usually assumes that the ground motions at structural supports are stationary processes. The development of time-frequency analysis technique makes it possible to evaluate the non-stationary responses of engineering structures subjected to non-stationary inputs, which is more general and realistic than the analysis method commonly used in engineering. In this paper, the wavelet-based stochastic vibration analysis methodology is adopted to calculate the non-stationary responses of multi-support structures. For comparison, the stationary response based on the standard random vibration method is also investigated. A frame structure and a two-span bridge are analyzed. The effects of non-stationary spatial ground motion and local site conditions are considered, and the influence of structural property on the structural responses are also considered. The analytical results demonstrate that the non-stationary spatial ground motions have significant influence on the response of multi-support structures.

Analysis of Amplification Factor Spectrum Using Strong Ground Motions Compatible to the Domestic Seismotectonic Characteristics (유사 강지진동을 이용한 수평 및 수직지반응답의 Amplification Factor 스펙트럼 분석)

  • 김준경;박창업;조봉곤;지헌철
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.1
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    • pp.25-29
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    • 1997
  • Amplication factor spectrum, using the observed strong ground motions database, has been obtained and compared with Standard Response Spectrum. The observed ground motions from the Miramichi, Nohanni, Sagueray and New Madrid Earthquake (19 vertical components, 36 horizontal components), which are estimated to represent domestic seismotectonic characteristics such as seismic sources, attenuation, and site effect, are used for the analysis of amplification factor spectrum. Amplication factors have been calculated by comparing the observed peak ground motions with results form responses to the observed horizontal and vertical ground motions. The comparison shows that the amplification factors resultant from this study exceed those of Standard Response Spectrum of relatively higher frequencies. The result implles that the characteristics of the seismic strong ground motion, which may represent the domestic seismotectonic characteristics differ from of standard Response Spectrum, especillay of higher frequencies.

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The Biological Effects of Calcium Phosphate Coated Implant for Osseointegration in Beagle Dogs (성견에 식립한 인산칼슘 피복 임플란트가 골조직 유착에 미치는 생물학적인 영향)

  • Shim, Eon-Cheol;Lim, Sung-Bin;Chung, Chin-Hyung;Kim, Jong-Yeo
    • Journal of Periodontal and Implant Science
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    • v.33 no.4
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    • pp.651-671
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    • 2003
  • The influence of calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated two types of titanium implants, i.e. as -machined ,as -machined with Ca-P coating, were prepared. The Ca-P coating produced by OCT Inc technique. These implants were inserted into the left and right femur of beagle dog, After implantation periods of 3 days, 1weeks, weeks, 4weeks, 8weeks, 12weeks. 24weeks, the bone-implant interface was evaluated histologically, histomorphometrically , and removal torque. Histological evaluation revealed no new bone formation around different implant materials after 2weeks of implantation. After 4 weeks, Ca-P coated implants showed a higher amount of bone contact than either of the non coated implants. After 12weeks, bone healing was almost completed. And implant were removed by reverse torque rotation with torque-measuring device. Mean torque values for 4weeks control were 2.375Kgf.cm and experimental were 2.725Kgf.cm. And mean torque values for 8weeks control were 1.25Kgf.cm and experimental were 1.0Kgf.cm On the basis of these findings, we concluded that deposition of a Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase. Besides implant surface conditions the bone response is also determined by local implant site condition.

Evaluation of the mechanical properties of discontinuous rock masses by using a bonded-particle model (입자결합모델을 이용한 불연속체 암반의 역학적 물성 평가)

  • Park Eui-Seob;Ryu Chang-Ha;Bae Seong-Ho
    • 한국터널공학회:학술대회논문집
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    • 2005.04a
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    • pp.348-358
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    • 2005
  • Although the evaluation of the mechanical properties and behavior of discontinuous rock masses is very important for the design of underground openings, it has always been considered the most difficult problem. One of the difficulties in describing the rock mass behavior is assigning the appropriate constitutive model. This limitation may be overcome with the progress in discrete element software such as PFC, which does not need the user to prescribe a constitutive model for rock mass. Instead, the micro-scale properties of the intact rock and joints are defined and the macro-scale response results from those properties and the geometry of the problem. In this paper, a $30m{\times}30m{\times}30m$ jointed rock mass of road tunnel site was analyzed. A discrete fracture network was developed from the joint geometry obtained from core logging and surface survey. Using the discontinuities geometry from the DFN model, PFC simulations were carried out, starting with the intact rock and systematically adding the joints and the stress-strain response was recorded for each case. With the stress-strain response curves, the mechanical properties of discontinuous rock masses were determined and compared to the results of empirical methods such as RMR, Q and GSI. The values of Young's modulus, Poisson's ratio and peak strength are almost similar from PFC model and Empirical methods. As expected, the presence of joints had a pronounced effect on mechanical properties of the rock mass. More importantly, the mechanical response of the PFC model was not determined by a user specified constitutive model.

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Performance Evaluation of Machine Learning Model for Seismic Response Prediction of Nuclear Power Plant Structures considering Aging deterioration (원전 구조물의 경년열화를 고려한 지진응답예측 기계학습 모델의 성능평가)

  • Kim, Hyun-Su;Kim, Yukyung;Lee, So Yeon;Jang, Jun Su
    • Journal of Korean Association for Spatial Structures
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    • v.24 no.3
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    • pp.43-51
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    • 2024
  • Dynamic responses of nuclear power plant structure subjected to earthquake loads should be carefully investigated for safety. Because nuclear power plant structure are usually constructed by material of reinforced concrete, the aging deterioration of R.C. have no small effect on structural behavior of nuclear power plant structure. Therefore, aging deterioration of R.C. nuclear power plant structure should be considered for exact prediction of seismic responses of the structure. In this study, a machine learning model for seismic response prediction of nuclear power plant structure was developed by considering aging deterioration. The OPR-1000 was selected as an example structure for numerical simulation. The OPR-1000 was originally designated as the Korean Standard Nuclear Power Plant (KSNP), and was re-designated as the OPR-1000 in 2005 for foreign sales. 500 artificial ground motions were generated based on site characteristics of Korea. Elastic modulus, damping ratio, poisson's ratio and density were selected to consider material property variation due to aging deterioration. Six machine learning algorithms such as, Decision Tree (DT), Random Forest (RF), Support Vector Machine (SVM), K-Nearest Neighbor (KNN), Artificial Neural Networks (ANN), eXtreme Gradient Boosting (XGBoost), were used t o construct seispic response prediction model. 13 intensity measures and 4 material properties were used input parameters of the training database. Performance evaluation was performed using metrics like root mean square error, mean square error, mean absolute error, and coefficient of determination. The optimization of hyperparameters was achieved through k-fold cross-validation and grid search techniques. The analysis results show that neural networks present good prediction performance considering aging deterioration.

A Study on the Safety through Response Analysis Evaluation of Pre-Anxiety Behavior and Risk Sensitivity Images (대응분석을 통한 안전·불안전 행동 및 위험감수성 이미지 평가)

  • Yu Mi Moon
    • Journal of the Society of Disaster Information
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    • v.20 no.3
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    • pp.471-483
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    • 2024
  • Purpose: This study aimed to understand the relationship between risk-sensitive factors and safety and unsafe behavior, and to clarify the relationship between risk-sensitive factors and demographic cha- racteristics through response matching analysis. To this end, a survey was conducted on 501 construc- tion site workers and data were analyzed using the SPSS program. Method: Six factors were derived through frequency analysis, cross-analysis, exploratory factor analysis, and reliability analysis for data purification. Multiple regression analysis and response analysis were conducted. Result: Risk-sensitive sensitivity and avoidance were found to have a significant effect on safety behavior and unsafe behavior, and the relationship was found according to age and occupation. Conclusion: Taken together, it shows that safety behavior is influenced by managing individual risk sensitivity and sensitivity, and properly managing avoidance. Accordingly, it suggests that intervention is necessary to manage risk sensitivity and sensitivity to promote safety behavior and maintain a sustainable safety culture, and to prevent excessive avoidance.

Seismic behavior of the shallow clayey basins subjected to obliquely incident wave

  • Khanbabazadeh, Hadi;Iyisan, Recep;Ozaslan, Bilal
    • Geomechanics and Engineering
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    • v.31 no.2
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    • pp.183-195
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    • 2022
  • Under the effects of the near-field earthquakes, the incident angle of the incoming wave could be different. In this study, the influences of some parameters such as incident angle, basin edge, peak ground acceleration level of the bedrock motion as well as different clay types with different consistency on the amplification behavior of the shallow basins are investigated. To attain this goal, the numerical analyses of the basins filled with three different clay types are performed using a fully nonlinear method. The two dimensional models of the basins are subjected to a set of strong ground motions with different peak ground acceleration levels and three different incident angles of 30◦, 45◦ and 90◦ with respect to the horizontal axes. The results show the dominant effect of the obliquely subjected waves at most cases. The higher effect of the 45◦ incident angle on the basin response was concluded. In the other part of this study, the spectral amplification curves of the surface points were compared. It was seen that the maximum spectral amplification of different surface points occurs at different periods. Also, it is affected by the increase in the peak acceleration level of the incoming motions.

Nonlinear Response Spectra of Artificial Earthquake Waves Compatible with Design Spectrum (설계용 스펙트럼에 적합한 인공지진파에 의한 비선형 응답 특성의 분석)

  • Jun, Dae-Han;Kang, Pyeong-Doo;Kim, Jae-Ung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.5 s.51
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    • pp.63-71
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    • 2006
  • In seismic response analysis of building structures, the input ground accelerations have considerable effect on the nonlinear response characteristics of structures. The characteristics of soil and the locality of the site where those ground motions were recorded affect on the contents of earthquake waves. Therefore, it is difficult to select appropriate input ground motions for seismic response analysis. This study describes a generation of artificial earthquake wave compatible with seismic design spectrum, and also evaluates the nonlinear response spectra by the simulated earthquake motions. The artificial earthquake wave are generated according to the previously recorded earthquake waves in past earthquake events. The artificial wave have identical phase angles to the recorded earthquake wave, and their overall response spectra are compatible with seismic design spectrum with 5% critical viscous damping. Each simulated earthquake wave has a identical phase angles to the original recorded ground acceleration, and match to design spectra in the range of period from 0.02 to 10.0 seconds. The seismic response analysis is performed to examine the nonlinear response characteristics of SDOF system subjected to the simulated earthquake waves. It was concluded that the artificial earthquake waves simulated in this paper are applicable as input ground motions for a seismic response analysis of building structures.