• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.829-841
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• 2018

An experiment was conducted for the OECD/NEA ROSA-2 Project using the large-scale test facility (LSTF), which simulated a 17% hot leg intermediate-break loss-of-coolant accident in a pressurized water reactor (PWR). In the LSTF test, core uncovery started simultaneously with liquid level drop in crossover leg downflow-side before loop seal clearing, and water remaining occurred on the upper core plate in the upper plenum. Results of the uncertainty analysis with RELAP5/MOD3.3 code clarified the influences of the combination of multiple uncertain parameters on peak cladding temperature within the defined uncertain ranges. For studying the scaling problems to extrapolate thermal-hydraulic phenomena observed in scaled-down facilities, an experiment was performed for the OECD/NEA PKL-3 Project with the Primarkreislaufe Versuchsanlage (PKL), as a counterpart to a previous LSTF test. The LSTF test simulated a PWR 1% hot leg small-break loss-of-coolant accident with steam generator secondary-side depressurization as an accident management measure and nitrogen gas inflow. Some discrepancies appeared between the LSTF and PKL test results for the primary pressure, the core collapsed liquid level, and the cladding surface temperature probably due to effects of differences between the LSTF and the PKL in configuration, geometry, and volumetric size.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1306-1311
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• 2004

The performance test apparatus of liquid-phase plate heat exchanger was installed and the computer program for design was developed in this study. The detail temperature distribution of hot and cold fluids in each path of heat exchanger was calculated by numerical method and the correlation for the heat transfer coefficient was defined. The heat transfer coefficients were measured using the working fluids of water and glycerine to investigate the effect of fluid viscosity. The measured heat transfer coefficients were compared with the calculated values obtained from the computer program and it was shown that error of the calculated values was generally less than 5%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.503-511
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• 2011

Water spray cooling is a significant technology for cooling of materials from high-temperature up to $900^{\circ}C$. The effects of cooling water temperature on spray cooling are mainly provided for hot steel plate cooling applications in this study. The heat flux measurements are introduced by a novel experimental technique that has a function of heat flux gauge in which test block assemblies are used to measure the heat flux distribution on the surface. The spray is produced by a fullcone nozzle and experiments are performed at fixed water impact density of G and fixed nozzle-totarget spacing. The results show that effects of water temperature on forced boiling heat transfer characteristics are presented for five different water temperatures between 5 to $45^{\circ}C$. The local heat flux curves and heat transfer coefficients are also provided to a benchmark data for the actual spray cooling of hot steel plate cooling applications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.668-676
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• 2003

The effect of nozzle height on heat transfer of a hot steel plate cooled by an impinging liquid jet is not well understood. Previous studies have been based on the dimensionless parameter z/d. To test the validity of this dimensionless parameter and to investigate gravitational effects on the jet, stagnation velocity of an impinging liquid jet were measured and the cooling experiments of a hot steel plate were conducted for z/d from 6.7 to 75, and an inverse heat conduction method is applied for the quantitative comparison. Also, the critical instability point of a liquid jet was examined over a range of flow rates. The experimental velocity data for the liquid jet were well correlated with the dimensionless number 1/F $r_{z}$$^2$based on distance. It was thought that the z/d parameter was not valid for heat transfer to an impinging liquid jet under gravitational forces. In the cooling experiments, heat transfer was independent of z when 1/F $r_{z}$$^2$< 0.187(z/d = 6.7). However, it was found that the heat transfer quantity for 1/F $r_{z}$$^2$=0.523(z/d = 70) is larger 11% than that in the region for 1/F $r_{z}$$^2$=0.187. The discrepancy between these results and previous research is likely due to the instability of liquid jet.uid jet.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.1
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• pp.81-94
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• 1988

A series of experiments was performed in this study to investigate the boiling heat flux between an impinging water jet and a hot surface. Test variables were surface roughness, jet velocity, saturation temperature excess of surface, nozzle diameter and the gap distance between nozzle plate and the hot surface. In order to make the impinged cooling water a forced flow streaming a long the hot surface immediately after the initial impingement, the flat nozzle tip was extended to a circular flat plate having the same diameter as the hot surface. Utilizing the dimensionless parameter study on continuity, momentum and energy equations, 5 groups of variables involved in the nucleate boiling heat transfer were derived so that it is possible to estimate the increased heat flux by impinging water jet in a similar experimental work. For the case of saturated water being impinging onto a high temperature surface, an applicable correlation among dimensionless parameters describing the heat flux was found to be as follow.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.317-320
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• 2004

Physiological effects of curcumin, major yellow-colored pigment in tumeric (Curcuma longa L.), extracted by traditional extracting methods, ethanol and hot-water extractions, and supercritical fluid extraction (SFE) using supercritical carbon dioxide as new extracting method. Antioxidative activity of ethanol extract was higher than those of SFE and hot-water extracts. Results of Ames mutagenicity test on SFE, ethanol, and hot-water extracts revealed no mutagen in the extracts. Antimutagenicity rates of SFE, ethanol, and hot-water extracts against direct mutagen, 2-nitrofluorene (2-NF), were 20.1, 9.3, and 15.2%, respectively. Antimutagenicity rate of SFE extract against TA98 derived from indirect mutagen, 2-acetamidofluorene (2-AF), was 12.2%, whereas none was observed in ethanol and hot-water extracts. Nitrite-scavenging ability of SFE extract was higher than those of ethanol and not-water extracts.

• Journal of Mechanical Science and Technology
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• v.18 no.10
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• pp.1819-1828
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• 2004

The purpose of this paper is to investigate the effects of slits and swirl vanes on the turbulence augmentation in the flow fields of a gun-type gas burner using an X-type hot-wire probe. The gun-type gas burner adopted in this study is composed of eight slits and swirl vanes located on the surface of an inclined baffle plate. Experiment was carried out at a flow rate of 450 ι/min in burner model installed in the test section of subsonic wind tunnel. Swirl vanes playa role diffusing main flow more remarkably toward the radial direction than axial one, but slits show a reverse feature. Consequently, both slits and swirl vanes remarkably increase turbulence intensity in the whole range of a gun-type gas burner with a cone-type baffle plate.

• Journal of Oriental Neuropsychiatry
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• v.15 no.1
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• pp.101-119
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• 2004

Ginseng Radix Alba and Cyperi Rhizoma were investigated for their anti-depressant effects. For this purpose, forced-swimming test, tail suspension test, hot plate test, reserpine-induced hypothermia, aggressive behavior test were performed. In addition, the brain content of 5-hydroxyindoleacetic acid(a metabolite of serotonin), the monoamine oxidase activity, anticonvulsant effect, sleep enhancement effect were determined. The results are as follows: In the forced swimming test, Ginseng Radix diminished the duration of immobility by 45.5% compared to the control group, while Cyperi Rhizoma showed weaker effect (12.4% reduction) at 2g/kg. In the tail suspension test, the effect of Ginseng Radix(43.7% reduction) are also better than that of Cyperi Rhizoma(15.6% reduction) at 2g/kg. In the hot plate test, Ginseng Radix showed no difference as compared to control, while Cyperi Rhizoma increased the jump latency time by about 25% after administration for 10 days. In the reserpine-induced hypothermia test, both drugs slowly dropped the body temperature compared to the control group, especially the rate of hypothermia of Ginseng Radix was 24.0% at 1g/kg. In the aggressive behavior test, both drugs delayed the onset time, decreased the duration and frequency, of which effects were better in Cyperi Rhizoma. The content of 5-hydroxyindoleacetic acid in mice brain was slightly increased in Ginseng Radix, while Cyperi Rhizoma increased its level almost to the control group. Both drugs inhibited the monoamine oxidase activity in a dose-dependent manner, but the effect(51.2%) of Cyperi Rhizoma was more potent than the effect(11.8%) of Ginseng Radix. In the pentobarbital-induced sleep test, Cyperi Rhizoma exhibited no significant difference against the control group, while Ginseng Radix showed about two-fold enhancement at 2g/kg. The anticonvulsant effect of both drugs delayed the onset time, shortened the duration of convulsion and diminished the lethality, but Ginseng Radix were better than Cyperi Rhizoma.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.5
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• pp.249-256
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• 2010

Water jet impingement cooling has been widely used in a various engineering applications; especially in cooling of hot steel plate of steelmaking processes and heat treatment in hot metals as an effective method of removing high heat flux. The effects of cooling water temperature on water jet impingement cooling are primarily investigated for hot steel plate cooling applications in this study. The local heat flux measurements are introduced by a novel experimental technique that has a function of high-temperature heat flux gauge in which test block assemblies are used to measure the heat flux distribution during water jet impingement cooling. The experiments are performed at fixed flow rate and fixed nozzle-to-target spacing. The results show that effects of cooling water temperature on the characteristics of jet impingement heat transfer are presented for five different water temperatures ranged from 5 to $45^{\circ}C$. The local heat flux curves and heat transfer coefficients are also provided with respect to different boiling regimes.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.222-230
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• 1993

Industrial glues, known as 'Bonds' in Korea, contain many kinds of organic solvents, and glue sniffing of youths became one of the social problems in Korea. Mixed exposures to solvents by glue sniffing may induce chronic toxicities different from those by exposures to solvents of single component. To test effects of the glue sniffing on weight gain or central nervous system, two groups of 20 male Sprague-Dawley rats were exposed to air(control group) or vapors of the glues to narcotic status(exposed group), and weight check, tail flick test, hot plate test, rotarod treadmill test were done on the 14th,24th, 36th, 45th, 53rd, 86th, 102nd, 117th, 134th and 151st days after the first exposure. On the 188th day, their brains were excised and examined by a pathologist. Weight gain, controlled against time change, showed significant difference between the groups, but response times in tail flick test, hot plate tests, and rotarod treadmill test didn't. In pathological examination with blind method, no macroscopic or microscopic differences were found between the two groups. These results suggests that organic lesion in central nervous system may not ensue glue sniffing, but, before firm conclusion, more studies in various exposure conditions should be followed.