• 설비공학논문집
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• 제29권12호
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• pp.654-662
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• 2017

When emergency core cooling system (ECCS) is operated during loss of coolant accident (LOCA) in a pressurized water reactor (PWR), pressurized thermal shock (PTS) phenomenon can occur as cooling water is injected into a cold leg, mixed with hot primary coolant, and then entrained into a reactor vessel. Insufficient flow mixing may cause temperature stratification and steam condensation. In addition, flow vibration may cause thermal stresses in surrounding structures. This will reduce the life of the reactor vessel. Due to the importance of PTS phenomenon, in this study, calculation was performed for Test 1 among six types of OECD/NEA ROSA tests with ANSYS CFX R.17. Predicted results were then compared to measured data. Additionally, because temperature difference between the hot coolant at the inlet of the cold leg and the cold cooling water at the inlet of the ECCS injection line is 200 K or more, buoyancy force due to density difference might have significant effect on thermal-hydraulic characteristics of flow. Therefore, in this study, the necessity to include buoyancy force term in governing equations for accurate prediction of single phase thermal stratification in both cold legs and downcomer by ECCS injection was numerically studied.

• 대한설비공학회지:설비저널
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• 제21권6호
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• pp.451-465
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• 1992

• 천문학회보
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• 제22권
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• pp.35.1-35.1
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• 1997

• 대한설비공학회지:설비저널
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• 제26권3호
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• pp.200-208
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• 1997

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.693-694
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• 2005

• 한국기계가공학회지
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• 제17권2호
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• pp.68-76
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• 2018

A vortex tube is a simple energy separating device that splits a compressed air stream into a cold and hot stream without any external energy supply or chemical reactions. The efforts of many researchers and designers have been focused on improvement of vortex tube efficiency by changing the parameters affecting vortex tube operation. The effective parameters are nozzle specifications and inflow pressure conditions. Effects of different nozzle cross-sectional area and number of nozzles are evaluated by computational fluid dynamics (CFD) analysis. In this study, CFD analysis of 3-D steady state and turbulent flow through a vortex tube was performed. We investigated the cold air mass flow rate, the cold air temperature, and the cold air heat transfer rate behavior of a vortex tube by utilizing seven straight nozzles and four inflow pressure conditions.

• 설비공학논문집
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• 제25권2호
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• pp.79-84
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• 2013

In this study, a cold aisle containment system was proposed among various strategies to reduce the energy waste by recirculation air from the hot aisle. To verify the effectiveness of the cold aisle containment system, a test bed which is similar to an actually existing server room was set up in the Internet Data Center(IDC) building. Comparative experiments, conventional open type cooling system and cold aisle containment system were carried out under actual conditions. The result revealed that the range of inlet temperature of the server system was $20{\sim}25^{\circ}C$ in an existing cooling system and the range of inlet temperature dropped below $20^{\circ}C$ by the cold aisle containment system. After all, cold aisle containment system was proved to be the solution for energy saving cooling system.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1185-1190
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• 2008

When 10 kinds of herbal medicines were fractionated into hexane, MeOH, cold-water, and hot-water extracts, hot-water extracts from Acanthopanax senticosus (AS), Glycyrrhiza uralensis (GU), Cichorium intybus (CI), and Polygonatum odoratum (PO) showed the potent intestinal immune system modulating activity (1.72-, 1.62-, 1.60-, and 1.53-fold of control at $100{\mu}g/mL$, respectively). Especially, hot-water extracts from AS (215% compared with the control) and GU (187%) also had macrophages stimulating activity and mitogenic activity of splenocytes (7.1- and 6.5-fold) at $100{\mu}g/mL$. In addition, the effects of hot-water extracts from herbal medicines on anticancer activities were studied in mice. Hot-water extracts from AS and GU enhanced cytotoxicity of natural killer cell against cancer cell, Yac-1 (37 and 34% cytotoxicity) at E/T ratio 100:1, and colon 26-M3.1 cancer cell lines had significantly inhibited (82.1 and 75.2%) in experimental lung metastasis. These results suggest that hot-water extracts from A. senticosus and G. uralensis can be used as biological response modifiers to stimulate immune system and inhibit tumor.

• 대한한의학회지
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• 제35권3호
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• pp.49-59
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• 2014

Background: Eight positions for new formulations in Jingyuequanshu is a unique classifying system and each position can be presented as a network. Network analysis is an effective method of visualizing the relationship of textual information. Purpose: This study aimed to analyze the structure of the eight positions for new formulations in Jingyuequanshu, and to acquire information about composing materia medica. Methods: We constructed an initial database and binary matrix of eight positions for new formulation in Jingyuequanshu, including its herbs and formulations. With this data, we carried out frequency and network analysis. Results: We analyzed each of the eight positions for new formulation, entire positions, and five positions after removing 'causal/cold/hot' positions. We found that the formulas of the causal position are distributed throughout the new formulation, and those of the cold and hot positions are also distributed similarly but the two groups are exclusive to each other. The other 5 positions are distributed exclusively to one another. Conclusions: Eight positions for new formulation of Jingyuequanshu were classified into three axes by exploratory network analysis. One is an axis of causal position, another is an axis of cold/hot positions, and the last is an axis of the other five positions.

• 대한환경공학회지
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• 제33권4호
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• pp.223-230
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• 2011

EMEP/EEA Emission Inventory Guidebook에 의하면 자동차 주행에 따른 총 대기오염물질 배출량을 Hot Start와 Cold Start로 구분해 산출하도록 하고 있다. 본 연구에서는 이러한 자동차 주행주기 특성을 감안하여 교통사업의 타당성 분석 시환경비용절감 편익의 현실적인 산정방안에 대해 검토하였다. 이를 위해 교통수요 분석모형(EMME/3)을 이용하여 분석영향권내 모든 링크단위의 교통량과 통행속도 자료를 활용하는 Tier 3 방식으로 환경오염 물질을 선출하였다. 본 연구에서 제안된 방법론의 적용성 검토를 위해 현재 계획중인 철도 투자평가사업에 적용하였으며, 적용결과 환경부문의 편익이 기존 대비 약 30% 정도 증가하는 것으로 나타났다. 향후 본 연구에서 제안한 방법론이 투자평가과정에서 적용된다면 철도와 같은 친환경 교통수단의 투자활성화에 기여할 것으로 기대한다.