• Nuclear Engineering and Technology
• /
• v.50 no.7
• /
• pp.1079-1087
• /
• 2018

There are many parameters that affect the natural circulation flow, such as height difference, heating power size, pipe diameter, system pressure and inlet temperature and so on. In general analysis the heating power is often regarded as a uniform distribution. The ANSYS-CFX numerical analysis software was used to analyze the flow heat transfer of supercritical water under different heating power distribution conditions. The distribution types of uniform, power increasing, power decreasing and sine function are investigated. Through the analysis, it can be concluded that different power distribution has a great influence on the flow of natural circulation if the total power of heating is constant. It was found that the peak flow of supercritical water natural circulation is maximal when the distribution of heating power is monotonically decreasing, minimal when it is monotonically increasing, and moderate at uniform or the sine type of heating. The simulation results further reveal the supercritical water under different heat transfer conditions on its flow characteristics. It can provide certain theory reference and system design for passive residual heat removal system about supercritical water.

• Nuclear Engineering and Technology
• /
• v.55 no.5
• /
• pp.1821-1829
• /
• 2023

The temperature distribution of the reactor pool under natural circulation induced by the RVACS operation was experimentally studied. According to the Bo' based similarity law, which could reproduce the temperature distribution of the working fluid under natural circulation, SINCRO-2D facility was designed based on the PGSFR. It was reduced to 1 : 25 in length scale, having water as a simulant of the sodium, which is the original working fluid. In general, temperature was stratified, however, effect of the natural circulation flow could be observed by the entrainment of the stratified temperature. Relative cooling contribution of the upper plenum (narrow gap) and lower plenum was approximately 0.2 and 0.8, respectively. In the range of decay heat from 0.2% to 1.0%, only the magnitude of the temperature was changed, while the normalized temperature maintained. Boundary temperature distribution change made a global temperature offset of the pool, without a significant local change. Therefore, the decay heat and cooling boundary condition had no significant effect on temperature distribution characteristics of the pool within the given range of the decay heat and boundary temperature distribution.

• Journal of Chest Surgery
• /
• v.25 no.1
• /
• pp.17-22
• /
• 1992

The alterations in serum and urine potassium were studied in twenty two patients who underwent open heart surgery using extracorporeal circulation from June 1990 to August 1990 at the Department of Thoracic and Cardiovascular Surgery, School of Medicine, Kei-myung University. There were fifteen cases congenital heart disease and seven acquired heart disease. The serum and urine potassium levels were measured pre-, intra- and postoperatively until seventh postoperative day using ionic selective electrode measuring method. After general anesthesia, the serum potassium level decreased significantly but slowly increased during.cardiopulmonary bypass and returned preoperative level after operation. The urine potassium level decreased slowly from general anesthesia to cardiopulmonary bypass weaning but returned preoperative level following operation. During cardiopulmonary bypass, serum and urine potassium levels in diuretic group were lower than that of non diuretic group. There was no remarkable difference in the serum potassium level between single RA cannulation group and bicaval cannulation group preoperatively, but the serum potassium level in single RA cannulation group was much higher than that of bicaval cannulation group. There was no significant difference in the urine potassium level between single RA can-nulation group and bicaval cannulation group postoperatively.

• The Korean Society of Law and Medicine
• /
• v.19 no.2
• /
• pp.209-233
• /
• 2018

The purpose of this study was to ascertain whether or not to recover the spontaneous circulation of patients with cardiac arrest before arrival in the emergency room for 5 years (2012 to 2016), and try to investigate the factors affecting this. In this research, we used the "raw material for acute cardiac arrest survey" conducted in "Disease management headquarters" from 2012 to 2016 for the whole country of our country as the main material. In this study, 136,212 cardiac arrest patients were analyzed in the study data of the cardiac arrest in the country during the 5 years from 2012 to 2016. We performed a Chi-square analysis to analyze the recovery of spontaneous circulation before arrival in the emergency room according to general characteristics, social·demographic characteristics, and developmental characteristics. and We performed a Binary logistic regression analysis to determine the factors affecting the recovery of spontaneous circulation. The analysis results of this study show that whether CPR sustained transport before endoplasmic reticulum arrival, whether to witness an acute cardiac arrest before arrival in the emergency room, the type of general cardiopulmonary resuscitation, the location of acute cardiac arrest, the acute heart Causes of stoppage cause factor of whether spontaneous circulation recovery recovers before arrival of the endoplasmic reticulum(P<0.001, P<0.01). Therefore, it is necessary to strengthen systematic government health policy implementation and dissemination and health education focusing on factors that affect recovery of spontaneous circulation of cardiac arrest patients.

• Journal of Korea Water Resources Association
• /
• v.52 no.12
• /
• pp.1011-1023
• /
• 2019

Rapid urbanization increases the risk of hydrologic disasters due to the increase of impervious areas in urban areas. Precipitation characteristics can be transformed due to the rise of global temperatures. Thus urban areas with the increased impervious areas are more exposed to hydrological disasters than ever before. Therefore, low impact development practices have been widely installed to rehabilitate the distorted hydrologic cycle in the urban area. This study used the Stormwater Management Model to analyze the water quantity and quality of the Mokgamcheon which had been severely urbanized, considering future climate scenarios presented by various general circulation models (GCMs). In addition the effectiveness of permeable pavement by 27 sub-watersheds was simulated in terms of water quantity and quality considering various GCMs and then the priorities of sub-watersheds were derived using an alternative valuation index which uses the pressure-state-response framework.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.25 no.4
• /
• pp.81-91
• /
• 2019

Purpose: Since infectious disease hospitals are premised on emergency operations, the operational efficiency of secured personnel, equipment, facilities, etc. is relatively low. In order to increase such normal operational efficiency, it is necessary to flexibly operate facilities and operations during normal and emergency times. The purpose of this study is to suggest the architectural planning method focusing on the space composition and circulation of the regional infectious disease hospital which can increase the operational efficiency in the private hospitals. Methods: Through literature review, functional requirements of infectious disease hospitals were identified, and related personnels inter-views and field surveys were conducted to understand the spatial composition and circulation requirements of infectious disease hospitals. Results: Through the complete separation between the negative pressure zone and the general zone, even when the negative pressure zone is completely closed, the general zone should be operated separately to achieve operational efficiency. In addition, the separation of the negative pressure zone and the general zone should simultaneously consider the optimal space configuration and movement for each function while the zone settings match in the floor plan of each department and the overall cross-sectional configuration of the hospital. Implications: Infectious disease hospitals intended to be installed in private hospitals should not apply excessive space just for safety reasons and should plan to ensure their operational efficiency.

• Journal of the Korean earth science society
• /
• v.27 no.6
• /
• pp.653-658
• /
• 2006

The seasonal predictability of typhoon activity over the western North Pacific is investigated using an atmospheric general circulation model GCPS. A ten-member ensemble with different initial conditions is integrated for five months using observed sea surface temperature data for each year from 1979 to 2003. It is shown that the monthly variation of occurrence frequency of simulated tropical storms and the distribution of tropical storm genesis location are similar to those of observed tropical storms, but the model is unable to reliably predict the interannual variation of the occurrence frequency of tropical storms. This is largely because the observed relationship between tropical storm occurrence frequency and ENSO is different from the simulated one. Unlike the observation, in which the tropical storm occurrence frequency has no relation to ENSO, the model has a tendency to generate more (less) tropical storms than normal during El Nino (La Nina). On the other hand, the interannual variation of the mean longitude of tropical storms that shows a close connection with ENSO in both observations and simulations is simulated similar to the observation.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.19 no.4
• /
• pp.47-60
• /
• 2013

Purpose: This study examines construction core plans for the users of vertical-typed general hospitals to effectivly use the flow line. Methods: The study sampled representative 9 hospitals, calculated the depth value through Convex Map of Space Syntax and Justified Graph according to the determination of form of construction cire, and analyzed its functional connectivity. Results: The analysis of the connectivity between operation core part and emergency part of core space with high importance in the hospitals showed that the types of hospital and hospital have the lowest depth value in the spatial phase diagram, where central treatment part and outpatient part are arranged well vertically. Elevators for patients at these hospitals are close to operation and emergency parts actually separated from the elevators for passengers. For shortening of flow line of patients and private movement environment, however, it is desirable to arrange the elevators for patients to be adjacent to the operation parts and to arrange the emergent patient entrances more effectively to separate them from the flow line of visitors and guardians. Implications: Consideration should be taken into account for the effective flow line design. This study hopefully may serve as a stepping stone for the standard design of horizontal/vertical flow line.

• Journal of the Korean earth science society
• /
• v.40 no.3
• /
• pp.203-211
• /
• 2019

The two key factors controlling the atmospheric general circulation are the equator-to-pole temperature difference and the Coriolis force driven by Earth's rotation. Although the former's role has been extensively examined, little has been reported about the latter's effect. To better understand the atmospheric general circulation, this study investigates the responses of Hadley Cell (HC) and westerly jet to the rotation faster or slower than the present Earth's rotation rate. It turns out that the HC edge and jet position tend to move equatorward and become weaker with increasing rotation rate. In most cases, the HC edge is quasi-linearly related with the jet position except for the extremely slow or fast rotating cases. The HC edge is more inversely proportional to the root of rotation rate than the rotation rate in the range of 1/8 to 8 times of the current Earth's rotation rate. However, such a relationship does not appear in the relationship between HC strength and jet intensity. This result highlights that while the latitudinal structure of atmospheric general circulation can be, to some extent, scaled with the Earth's rotation rate, overall intensity cannot be simply explained by the Earth's rotation rate.

• Journal of Korea Water Resources Association
• /
• v.52 no.5
• /
• pp.337-347
• /
• 2019

This study proposes the framework to select the representative general circulation model (GCM) for climate change projection. The grid-based results of GCMs were transformed to all considered meteorological stations using inverse distance weighted (IDW) method and its results were compared to the observed precipitation. Six quantile mapping methods and random forest method were used to correct the bias between GCM's and the observation data. Thus, the empirical quantile which belongs to non-parameteric transformation method was selected as a best bias correction method by comparing the measures of performance indicators. Then, one of the multi-criteria decision techniques, TOPSIS (Technique for Order of Preference by Ideal Solution), was used to find the representative GCM using the performances of four GCMs after the bias correction using empirical quantile method. As a result, GISS-E2-R was the best and followed by MIROC5, CSIRO-Mk3-6-0, and CCSM4. Because these results are limited several GCMs, different results will be expected if more GCM data considered.