• 한국농공학회논문집
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• 제60권1호
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• pp.89-99
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• 2018

This study analyzed the change of the dam inflow and evapotranspiration in the Soyanggang dam basin using the results of 26 CMIP5 GCMs based on AR5 RCP 4.5 and RCP 8.5 scenarios. The SWAT model was used to simulate the dam inflow and evapotranspiration in the target watershed. The simulation was performed during 2010~2016 as the reference year and during 2010~2099 as the analysis period. Bias correction of input data such as precipitation and air temperature were conducted for the reference period of 2006~2016. Results were analyzed for 3 different periods, 2025s (2010~2040), 2055s (2041~2070), and 2085s (2071~2099). It demonstrated that the change of dam inflow gradually increases 9.5~15.9 % for RCP 4.5 and 13.3~29.8 % for RCP 8.5. The change of evapotranspiration gradually increases 1.6~8.6 % for RCP 4.5 and 1.5~8.5 % for RCP8.5.

• 한국환경보건학회지
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• 제26권4호
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• pp.97-104
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• 2000

The purpose of this is made an examination of phosphorus loading model for eutrophication response in the Yongsan lake. For the model, we measured the total amount of nutrients derived from the Yongsan river watershed, inflow rate to the Yongsan lake, water quality, and water budget from January to December in 1999. The total amount of precipitation in the Yongsan river watershed was 4,951.7$\times$10$^{6}$ ㎥/y and inflow amount was 2,569.7$\times$10$^{6}$ ㎥/y, therefore the outflow rate of the Yongsan river watershed was 51.9%. The develop loading of total nitrogen was 86,928.1kg/d and that of total phosphorus was 22,007.6kg/d at the Yongsan river watershed, But, as the inflow loading of total nitrogen was 33,962kg/d and the inflow loading of total phosphorus was 2,218kg/d to the Yongsan lake. so each infolw rate was 39.0% and 10.1%. The hydraulic residence time was 34days, total phosphorus loading [L(P)] on the surface area was 23.398g/㎥/y, the hydraulic load( $Q_{s}$) of inflow water was 74.269m/y, the reserve rate of phosphorus in the lake was 0.359, and the settinh velocity of phosphorus was 0.114m/d at the Yongsan lake. Mathematical model of phosphorus loading to estimate the responses of eutrophication at the Yongsan lake is [ $P_{j}$] = 0.838 [L(P)/Q.(1+√ $T_{w}$)$^{-1}$ ] . ] . .

• 대한원격탐사학회지
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• 제24권1호
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• pp.25-33
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• 2008

To investigate the hydrologic impacts of climate changes on dam inflow for Soyanggangdam watershed $(2694.4km^2)$ of northeastern South Korea, SLURP (Semi-distributed Land Use-based Runoff Process) model and the climate change results of CCCma CGCM2 based on SRES A2 and B2 were adopted. By the CA-Markov technique, future land use changes were estimated using the three land cover maps (1985, 1990, 2000) classified by Landsat TM satellite images. NDVI values for 2050 and 2100 land uses were estimated from the relationship of NDVI-Temperature linear regression derived from the observed data (1998-2002). Before the assessment, the SLURP model was calibrated and verified using 4 years (1998-2001) dam inflow data with the Nash-Sutcliffe efficiencies of 0.61 to 0.77. In case of A2 scenario, the dam inflows of 2050 and 2100 decreased 49.7 % and 25.0 % comparing with the dam inflow of 2000, and in case of B2 scenario, the dam inflows of 2050 and 2100 decreased 45.3 % and 53.0 %, respectively. The results showed that the impact of land use change covered 2.3 % to 4.9 % for the dam inflow change.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권3호
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• pp.1-10
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• 2022

Most wells developed in Jeju island before the enactment of the Groundwater Management Ordinance in 2002 are vulnerable to aquifer contamination due to inflow of upper groundwater having the high concentration of nitrate nitrogen, likely due to incomplete grouting in upper section of the wells. Although these wells require entire reinstallation, it is often necessary to rehabilitate the existing wells due to various constraints. Therefore, to identified the inflow section of contaminants, the thermal level sensor (TLS) technique was firstly applied for three wells, which enables to monitor temperature variations in every 50 cm depth. Then, the grouting material was injected to the upper section to prevent the inflow of upper contaminated groundwater into the entire aquifer. By applying TLS technique, it was found that the temperature deviations in the upper groundwater inflow section decreased sharply. Moreover, both the change in the concentration of nitrate nitrogen in the rainy/dry seasons and the average concentrations were found to decrease rapidly after grouting material injection. Consequently, the application of TLS proposed in the study turned out to be appropriate to prevent aquifer contamination.

• 한국환경과학회지
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• 제31권5호
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• pp.431-445
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• 2022

The Gwangju Stream is a major tributary of the Yeongsan River. To maintain environmental and ecological functions in the stream, the flow is secured by natural water from the Mudeung Mountain as well as waters discharged from Lake Juam and the Gwangju sewage treatment plants. A substantial amount of water is supplied into the upper reaches of Gwangju Stream from Lake Juam. To examine the ecological effects of the water input from Lake Juam on the Gwangju Stream, a field survey of phytoplankton community species and an evaluation of water properties was conducted at five stations, from station GJ1 before the inflow to station GJ5 in the lower region. Nutrient levels decreased in the vicinity of the Lake Juam inflow, suggesting that this water inflow can contribute to the reduction of eutrophication in the stream. The phytoplankton community was mainly composed of Bacillariophyceae, Chlorophyceae, and Cyanophyceae, and the community structure was similar to that of the other study sites located near the water inflow regions. The inflow of water from Lake Juam can affect water quality and the phytoplankton community over a limited area, reducing eutrophication and increasing water flow in the Gwangju Stream.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1310-1323
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• 2023

A reactor coolant pump (RCP) is essential for transporting coolant in the primary loop of pressurized water reactors. In the advanced passive reactor, the absence of a long pipeline between the steam generator and RCP serves as a transition section, resulting in a non-uniform flow field at the pump inlet. Therefore, the characteristics of the pump should be investigated under non-uniform flow to determine its influence on the pump. In this study, the pressure pulsation characteristics were examined in the time and frequency domains, and the sources of low-frequency and high-amplitude signals were analyzed using wavelet coherence analysis and numerical simulation. From computational fluid dynamics (CFD) results, non-uniform inflow has a great effect on the flow structures in the pump's inlet. The pressure pulsation in the pump at the rated flow increased by 78-128.7% under the non-uniform inflow condition in comparison with that observed under the uniform inflow condition. Furthermore, a low-frequency signal with a high amplitude was observed, whose energy increased significantly under non-uniform flow. The wavelet coherence and CFD analysis verified that the source of this signal was the low-frequency pulsating vortex under the steam generator.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1604-1615
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• 2023

In an open-pool type research reactor with a downward forced flow in the core, pipes can be under sub-atmospheric pressure because of the large pressure drop at the reactor core in the atmospheric pool. Sub-atmospheric pressure can result in air inflow into the pipe from the pressure difference between the atmosphere and the inside of the pipe, which in a postulated pipe break scenario can lead to the breakdown of the cooling pump. In this study, a plant-scale experiment was conducted to study air inflow in large piping systems by considering the actual operational conditions of an advanced research reactor. The air inflow rate was measured, and the entrained air was visualized to investigate the behavior of air inflow and flow regime depending on the pipe break size. In addition, the developed drift-flux model for a large vertical pipe with a diameter of 600 mm was compared with other correlations. The flow regime transition in a large vertical pipe under downward flow was also studied using the newly developed drift-flux model. Consequently, the characteristics of two-phase flow in a large vertical pipe were found to differ from those in small vertical pipes where liquid recirculation was not dominant.

• 천문학회보
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• 제46권1호
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• pp.51.2-51.2
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• 2021

Nuclear rings are sites of intense star formation at the center of barred spiral galaxies. A straightforward but unanswered question is what controls star formation rate (SFR) in nuclear rings. To understand how the ring SFR is related to mass inflow rate, gas content, and background gravitational field, we run a series of semi-global hydrodynamic simulations of nuclear rings, adopting the TIGRESS framework to handle radiative heating and cooling as well as star formation and supernova feedback. We find: 1) when the mass inflow rate is constant, star formation proceeds in a remarkably steady fashion, without showing any burst-quench behavior suggested in the literature; 2) the steady state SFR has a simple linear relationship with the inflow rate rather than the ring gas mass; 3) the midplane pressure balances the weight of the overlying gas and the SFR surface density is linearly correlated with the midplane pressure, consistent with the self-regulated star formation theory. We suggest that the ring SFR is controlled by the mass inflow rate in the first place, while the gas mass adjusts to the resulting feedback in the course of achieving the vertical dynamical equilibrium.

• 한국간담췌외과학회지
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• 제27권2호
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• pp.131-140
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• 2023

During minimally invasive liver resection (MILR), the Pringle maneuver aims to minimize blood loss and provide a clear operative field, thereby identifying intrahepatic structures and facilitating safe parenchymal transection. Several techniques for using the Pringle maneuver in MILR have been described. This review presents various methods which have been reported in the literature. A systematic literature search used the MEDLINE/PubMed database from its earliest records to August 2022 using appropriate search headings and keywords. The primary outcome was identifying techniques for performing hepatic inflow occlusion during laparoscopic/robotic hepatectomy. Inclusion criteria consisted of publications describing technical steps to obtain hepatic inflow occlusion during minimally invasive hepatectomy. A literature search identified 23 relevant publications, and the full texts were examined. The techniques described in the reports can be broadly categorized into three groups: (1) the Rummel-tourniquet technique, (2) vascular clamp use, and (3) the Huang Loop technique. Various techniques have been used in MILR to achieve inflow confinement successfully. The authors prefer the modified Huang Loop technique because it is inexpensive, reliable, and quick to apply or release. Hepatobiliary surgeons are advised to familiarize themselves with these MILR techniques, which have proven effective and safe inflow occlusion.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.543-546
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• 2003

This study was carried out to survey the amount of inflow water from Geumgang reservoir, Yongdam dam and Sumjin dam into Saemangeum area, and to provide the basic data to use and manage the water resources of Saemangeum district effectively. The total volume of inflow water from the above hydraulic facilities was measured as $775.8{\times}10^6m^3$ in 2002.