• Annals of Hepato-Biliary-Pancreatic Surgery
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• 제27권4호
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• pp.394-402
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• 2023

Backgrounds/Aims: Acute pancreatitis is an emergency presentation, which can range from mild to life threatening. Intravenous fluids are the cornerstone of management. Although the WATERFALL trial described the optimal fluid rate in mild/moderate pancreatitis, this trial excluded patients with moderate-severe/severe pancreatitis. The aim of this study was to establish clinical practice regarding intravenous fluid administration in acute pancreatitis and assess its effect on mortality. Methods: Prospective multi-centre audit of patients with acute pancreatitis was conducted. Data were collected regarding intravenous fluid administration within 72 hours of admission. The primary outcome was 30-day mortality. Multivariable logistic regression was used to identify predictors of 30-day mortality. Results: Those with severe pancreatitis received more fluid; median 5.7 L versus 4 L in 72 hours (p = 0.003). Participants with severe pancreatitis who died within 30 days received a median of 2,750 mL in the first 24 hours, compared to 4,000 mL in those who survived. The following factors were significant predictors of 30-day mortality: age, Glasgow score, C-reactive protein, ischaemic heart disease, and pancreatitis aetiology. Overall, volume of intravenous fluid was not associated with mortality. However, the effect of intravenous fluid volume on mortality differed significantly depending on pancreatitis severity. In severe pancreatitis, increased volume of intravenous fluid was associated with significant reductions in mortality (odds ratio = 0.655; 0.459-0.936; p = 0.020). Conclusions: In severe pancreatitis, more aggressive fluid prescription was associated with decreased mortality; however, this was not the case in milder disease. Further prospective trials guiding fluid resuscitation in severe pancreatitis are needed, as the impact of fluid on this population appears to differ from that in those with milder disease.

• Journal of Korean Neurosurgical Society
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• 제58권6호
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• pp.554-556
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• 2015

Primary intracranial malignant melanoma is a very rare and highly aggressive tumor with poor prognosis. A 66-year-old female patient presented a headache that had been slowly progressing for several months. A large benign pigmented skin lesion was found on her back. A brain MRI showed multiple linear signal changes with branching pattern and strong enhancement in the temporal lobe. The cytological and immunohiostochemical cerebrospinal fluid examination confirmed malignant melanoma. A biopsy confirmed that the pigmented skin lesion on the back and the conjunctiva were benign nevi. We report a case of primary intracranial malignant melanoma and review relevant literatures.

• Journal of KSNVE
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• 제7권4호
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• pp.655-661
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• 1997

Base-isolation of a primary structure generally decrete the seismic response of its own and the secondary structure. It may cause an adverse effect on the seismic response of secondary system when the system is submerged and subject to a considerable hydrodynamic effect. In this paper, it is shown how, and how much, the base isolation of the primary structure can affect the secondary system response in extreme cases through dynamic analysis of a simplified coupled model for a submerged secondary system and a base-isolated primary structure. As an aseismatic design approach to reduce the response of the submerged system, optimization of the fluid gap, which controls the hydrodynamic mass effect, is performed. As an alternative approach in case where the control of fluid gap is unrealistic, application of base isolation to the submerged system is suggested. Effectiveness of various combinations of the primary base and secondary base isolations are compared.

• Journal of Korea Foundry Society
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• 제16권6호
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• pp.565-575
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• 1996

In this study, to gain the semi-solid alloy we employed the electromagnetic rotation by a induction motor of 3-phases and 2-poles for Al-7wt%Si alloy and observed the size of primary solid particle, distribution state of primary solid particle, the degree of sphericity, and fraction of primary solid for the evaluation of its results. The size of primary solid particle increases from $98{\mu}m$ to $118{\mu}m$ as solid fraction increases from 0.2 to 0.5. The degree of sphericity increased as the solid fraction increased. Solid particles obtained from the microstructures of isothermally held sample were coarsened and the degree of sphericity was enhanced as isothermal holding time increased. However, when the sample was stirred for more than 40min, solid particles merged together and liquid phase was entrapped within the cluster of solid particles. The size of primary solid particle was not changed significantly with the variation of input voltages by 160V over which solid particles began to merge together to be a large cluster of about $170{\mu}m$ at 180V. The standard deviation and the degree of sphericity were not changed significantly with the variation of input voltage.

• Proceedings of the KSME Conference
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2145-2150
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• 2003

Ejector system is one of fluid machinery which can entrain the fluid in low pressure part and transport it to the higher pressure part. The ejector system has been widely used for the purpose of obtaining high-vacuum state, fluid transport, thrust augmentation, etc. It can transport a large capacity of fluid with relatively small device of no any moving parts, and thus seldom causes mechanical troubles. However, the conventional ejector system has been pointed out that its overall efficiency is quite low compared with other fluid machinery since it is derived by only the pure shear stresses. In the present study, 4, 6, and 8 lobed petal nozzles with a design Mach number of 1.7 are adopted as a primary nozzle to improve the ejector performance, and are compared with a conventional circular nozzle. The static pressures along the diffuser wall are measured to qualify the flow field inside the supersonic petal ejector system.

• Journal of the Korean Ceramic Society
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• 제40권12호
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• pp.1220-1223
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• 2003

TiO$_2$ and TiO$_2$-CdS which were expected to be highly activated photocatalysts with semiconductor properties, were prepared using supercritical fluid method. The powders prepared by supercritical fluid were agglomerate foam in 2-3 ${\mu}{\textrm}{m}$ size and the primary particles of 20 nm were arranged in the powders. The powders which were prepared by supercritical fluid method were anatase phase without any heat treatment.

• Journal of the Korean Institute of Gas
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• 제2권1호
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• pp.83-89
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• 1998

Experiments had been conducted Qualitatively regarding flow measurement errors of orifice flowmeter due to temperature difference between the inside and outside the natural gas meter-run in case of no pipe insulations. The primary factors considered in this study are fluid velocity and surrounding temperature. In addition, a portion of thermal radiation due to the sun was involved as a factor. The results showed that the considerable errors were not detected even in conditions of low flow rates and large temperature difference between the inside and outside the meter-run.

• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1008-1016
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• 2019

In the SG (steam generator) of PWR (pressurized water reactor) for a nuclear plant, hundreds of U-shaped tubes are used for the heat exchanger system. They interact with primary pressurized cooling water flow, generating flow-induced vibration in the secondary flow region. A simplified U-tube model is proposed in this study to apply for experiment and its counterpart computation. Using the commercial code, ANSYS-CFX, we first verified the Moody chart, comparing the straight pipe theory with the results derived from CFD (computational fluid dynamics) analysis. Considering the virtual mass of fluid, we computed the major modes with the low natural frequencies through the comparison with impact hammer test, and then investigated the effect of pump flow in the frequency domain using FFT (fast Fourier transform) analysis of the experimental data. Using two-way fluid-structure interaction module in the CFD code, we studied the influence on mean flow rate to generate the displacement data. A feasible CFD method has been setup in this research that could be applied potentially in the field of nuclear thermal-hydraulics.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1842-1852
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• 2019

The AP1000 reactor coolant pump is a vertical shielded-mixed flow pump, is the most important coolant power supply and energy exchange equipment in nuclear reactor primary circuit system, whose steadystate and transient performance affect the safety of the whole nuclear island. Moreover, safety demonstration of reactor coolant pump is the most important step to judge whether it can be practiced, among which software simulation is the first step of theoretical verification. This paper mainly introduces the fluid-solid coupling simulation method applied to reactor coolant pump, studying the feasibility of simulation results based on workbench fluid-solid coupling technology. The study found that: for the unsteady calculations of the pure liquid media, the average head of the reactor coolant pump with bidirectional fluid-solid coupling decreases to a certain extent. And the coupling result is closer to the real experimental value. The large stress and deformation of rotor under different flow conditions are mainly distributed on impeller and idler, and the stress concentration mainly occurs at the junction of front cover plate and blade outlet. Among the factors that affect the dynamic stress change of rotor, the pressure load takes a dominant position.

• Design & Manufacturing
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• 제15권1호
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• pp.66-71
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• 2021

In this study, die turning injection(DTI) mold design for manufacturing reservoir fluid tanks used for cooling in-vehicle batteries, inverters, and motors was conducted based on multi-field CAE. Part design, performance evaluation, and mold design of the reservoir fluid tank was performed. The frequency response characteristics through modal and harmonic response analysis to satisfy the automotive performance test items for the designed part were examined. Analysis of re-melting characteristics and structural analysis of the driving part for designing the rotating die of the DTI mold were performed. Part design was possible when the natural frequency performance value of 32Hz or higher was satisfied through finite element analysis, and the temperature distribution and deformation characteristics of the part after injection molding were found through the first injection molding analysis. In addition, it can be seen that the temperature change of the primary part greatly influences the re-melting characteristics during the secondary injection. The minimum force for driving the turning die of the designed mold was calculated through structural analysis. Hydraulic system design was possible. Finally, a precise and efficient DTI mold design for the reservoir fluid tank was possible through presented multi-field CAE process.