• 한국지반환경공학회 논문집
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• 제2권1호
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• pp.81-89
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• 2001

본 연구에서는 차수벽 재료로 자주 사용되는 흙-벤토나이트 혼합물의 투수계수가 해수로 인하여 어떻게 영향을 받는지 고찰하였으며 혼합물로 축조된 가상의 제방에 해수가 침입할 때 어떻게 영향을 받는지를 고찰하였다. 유한요소법을 이용한 RFP 방법을 사용하였으며 투수계수변화를 이 해석에 도입하였다. 해석을 위하여 정상흐름상태와 비정상 흐름 상태에서 경계면을 구한 결과 투수계수변화를 고려하지 않았던 과거의 방법과 비교할 때 해수쪽으로는 낮게 담수영역에서는 경계면이 높게 나타났다.

• 한국항만학회지
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• 제14권4호
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• pp.451-461
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• 2000

The design and maintenance of navigation channel and water facilities of an harbor which is located at the mouth of river or at the estuary area are difficult due to the complexity of estuarial water and sediment circulation. Effects of deepening navigable waterways, of changing coastline configurations, or of discharging dredged material to the open sea are necessary to be investigated and predicted in terms of water quality and possible physical changes to the coastal environment. A borad analysis of the transport mechanism in the estuary area was made in terms of sediment property, falling velocity, concentration and flow characteristics. In order to simulate the transport processes, a two-dimensional finite element model is developed, which includes erosion, transport and deposition mechanism of suspended sediments. Galerkin’s weighted residual method is used to solve the transient convection-diffusion equation. The fluid domain is subdivided into a series of triangular elements in which a quadratic approximation is made for suspended sediment concentration. Model could deal with a continuous aggregation by stipulating the settling velocity of the flocs in each element. The model provides suspended sediment concentration, bed shear stress, erosion versus deposition rate and bed profile at the given time step.

• Journal of Chest Surgery
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• 제32권9호
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• pp.823-826
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• 1999

주대동맥폐동맥간 부행혈관, 심실중격결손과 폐동맥 형성부전이 동반된 6개월된 환아에서 Clamshell 절개 를 통한 일차 완전교정술을 시행하였다. 수술 후 특별한 합병증은 없었으며, 초음파 검사상 남아있는 심실중 격결손이나 의미있는 폐동맥 협착 소견을 보이지 않았다. 이러한 질환의 수술적 접근에 \ulcorner폐로 공급되는 혈 류의 형태에 따라 다양한 방법이 존재하는데, 최근 들어서는 일차 완전교정술에 대한 여러 형태의 수술방법 이 제시되고 있으며, 그 적용 또한 확대되고 있다. 본 증례의 경우 Clamshell 절개 방법을 적용함으로써 종격 동내 병변에 대한 접근이 용이하였으며, 수술 결과 및 합병증 등의 측면에서도 일차 완전교정술의 한 방법 으로 고려해 볼만하다고 여겨진다.

• Journal of Ship and Ocean Technology
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• 제9권3호
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• pp.1-13
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• 2005

A design procedure for a ship with minimum total resistance has been developed using a numerical optimization method called SQP (Sequential Quadratic Programming) to search for optimized hull form and CFD(Computational Fluid Dynamics) technique. The friction resistance is estimated using the ITTC 1957 model-ship correlation line formula and the wave making resistance is evaluated using a potential-flow panel method based on Rankine sources with nonlinear free surface boundary conditions. The geometry of hull surface is represented and modified using B-spline surface patches during the optimization process. Using the Series 60 hull ($C_B$ =0.60) as a base hull, the optimization procedure is applied to obtain an optimal hull that produces the minimum total resistance for the given constraints. To verify the validity of the result, the original model and the optimized model obtained by the optimization process have been built and tested in a towing tank. It is shown that the optimal hull obtained around $13\%$ reduction in the total resistance and around $40\%$ reduction in the residual resistance at a speed tested compared with that of the original one, demonstrating that the present optimization tool can be effectively used for efficient hull form designs.

• Archives of Pharmacal Research
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• 제13권3호
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• pp.227-232
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• 1990

A Physiologically based pharmacokinetic model was used to describe the distribition and elimination of cefriazone in the rat. To validate the practical application of the model, the effect of cffeine on the model was also examined. The model consisted of eleven compartments representing the major sites for ceftriaxone distribution including carcass which served as a residual compartment. Elimination was represented by renal and hepatic (metabolic biliary )excretion with GI secretion and re-absorption. The drug concentrations in most of the tissues were simulated using flow limited equations while brain levels were simulated using membrane limited passive diffusion distribution. The experimental data were obtained by averaging the concentration of drug in the plasma and tissues of five rats after i. v. injection of cefriazone 100 mg/kg without and with caffeine 20 mg/kg. The data for the amount of ceftriazone excreted in urine and gut contents were used to apportion total body clearance. HPLC with UV detection was used for the assay with 0.1-0.2 $\mu$g/ml sensitivity. The great majority of drug concentrations with and without caffeine show reasonably good agreements to the simulation results within 20%. The effect of caffeine on renal and hepatic clearances was apparent with 18.8% and 18.6% increase in the model values, respectively.

• 풍력에너지저널
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• 제9권4호
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• pp.9-15
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• 2018

In a previous study, a technique for measuring wind speed and direction by using a roll-rotating three-axis ultrasonic anemometer was proposed and verified by wind tunnel tests. In the tests, instead of a roll sensor, roll angle was trimmed to make no up flow in the transformed wind speeds. Verification was done in point of the residual error of the rotation effect treatment. In this study, roll angle was measured from the roll motor encoder and the transformed wind speed and direction on the test section axis were compared with the ones provided to the test section. As a result, up to yaw $20^{\circ}$ at a wind speed of 12 m/sec or over, the RMS error of wind speed was within the double of the ultrasonic anemometer error. But at yaw $30^{\circ}$, it was over the double of the ultrasonic anemometer error. Regardless of wind speed, at yaw $20^{\circ}$ and $30^{\circ}$, the direction error was within the double of the ultrasonic anemometer error. But at yaw $10^{\circ}$ or less, it was within the error of the ultrasonic anemometer itself. This is a very favorable characteristic to be used for wind turbine yaw control.

• 한국폐기물자원순환학회지
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• 제35권8호
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• pp.709-720
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• 2018

Since the import ban of plastic waste in China has been enforced, plastic wastes were not properly collected and recycled in Korea. Hence, the management strategies for plastic waste in Korea should be improved by examining the regulations and policy in developed countries such as United States, Japan, EU and United Kingdom. The management strategy for the recycling cycle should be implemented to expand the labeling system of separation and discharge, reduce the consumption of plastic products, automate the separation and sorting method in recycling facilities, and improve the economical efficiency of the recycling cycle. The concept of residual waste (secondary waste) in the material flow analysis should be implemented to identify the shortage point in the plastic waste stream. Finally, the cooperation with international communities is required for a transboundary movement of plastic waste, which includes participation at the working group of international standards to recycle plastic waste.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3166-3175
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• 2022

The most numerical investigations of the thermal-hydraulic phenomena following the loss of the residual heat removal capability during the mid-loop operation of the pressurized water reactor were performed according to simplifications and are not sufficiently accurate. To perform more accurate and more reliable predictions of thermal-hydraulic accidents in a nuclear power plant using computational fluid dynamics codes, a more detailed methodology is needed. Modelling results identified that thermal stratification and natural convection are observed. Temperatures of lower monitoring points remain low, while temperatures of upper monitoring points increase over time. The water in the heated region, in the upper unheated region and the pipe region was well mixed due to natural convection, meanwhile, there is no natural convection in the lower unheated region. Water temperature in the pipe region increased after a certain time delay due to circulation of flow induced by natural convection in the heated and upper unheated regions. The modelling results correspond to the experimental data. The developed computational fluid dynamics methodology could be applied for modelling of two-component single/two-phase natural convection and thermal stratification phenomena during the mid-loop operation of the pressurized water reactor or other nuclear and non-nuclear installations at similar conditions.

• Journal of Veterinary Science
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• 제23권4호
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• pp.39.1-39.5
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• 2022

Patent ductus arteriosus (PDA) is a rare congenital cardiovascular anomaly in cats. Due to their small body, intercostal thoracotomy is the most common option to close the PDA. However, few reports detail the surgical technique for ligating PDA in kittens. In this case report, three cats weighing 1.4 kg, 1.2 kg, and 2.9 kg were diagnosed PDA. Clip ligation via left fourth intercostal thoracotomy was performed and the cats were successfully treated. Postoperative echocardiography showed no residual flow in any of the cases. This case report highlights clip occlusion for small cats with PDA could be safe and effective.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.3930-3943
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• 2021

To improve the capability of the SAS4A code, which simulates the initiating phase of core disruptive accidents for MOX-fueled Sodium-cooled Fast Reactors (SFRs), the authors have investigated in detail the physical phenomena under unprotected loss-of-flow (ULOF) conditions in a previous paper (Kawada and Suzuki, 2020) [1]. As the conclusion of the last article, fuel stub motion, in which the residual fuel pellets would move toward the core central region after fuel pin disruption, was identified as one of the key phenomena to be appropriately simulated for the initiating phase of ULOF. In the present paper, based on the analysis of the experimental data, the behaviors related to the stub motion were evaluated and quantified by the author from scratch. A simple model describing fuel stub motion, which was not modeled in the previous SAS4A code, was newly proposed. The applicability of the proposed model was validated through a series of analyses for the CABRI experiments, by which the stub motion would be represented with reasonable conservativeness for the reactivity evaluation of disrupted core.