• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1590-1596
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• 2003

The experiments of boiling heat transfer were performed to investigate the boiling enhancement in saturated water by using multi-stage electroplated surface. In order to optimize the boiling performance, current flux and duration in multi-stage electroplating were varied. Current flux, 2 $A/12cm^2$ and 0.33 $A/cm^2$, and duration ranging from 15 second to 50 second are considered. The results showed that multi-stage electro plated surfaces generate enhancement of boiling parameters such as boiling incipient superheat, boiling heat transfer coefficient, and critical heat flux compared to plain surface. The SEM images of the coated surfaces were captured to examine the structure of porous surface, which provides the enhancement of boiling heat transfer.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.503-517
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• 1995

A mechanistic model for forced convective transition boiling has been developed to predict transition boiling heat flux realistically. This model is based on a postulated multi­stage boiling process occurring during the passage time of an elongated vapor blanket specified at a critical heat flux condition. Between the departure from nucleate boiling (DNB) and the departure from film boiling (DFB) points, the boiling heat transfer is established through three boiling stages, namely, the macrolayer evaporation and dryout governed by nucleate boiling in a thin liquid film and the unstable film boiling. The total heat transfer rate during the transition boiling is the sum of the heat transfer rates after the DNB weighted by the time fractions of each stage, which are defined as the ratio of each stage duration to the vapor blanket passage time. The model predictions are compared with some available experimental transition boiling data. From these comparisons, it can be seen that the transition boiling heat fluxes including the maximum heat flux and the minimum film boiling heat flux are nil predicted at low qualities/high pressures near 10 bar.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.262-267
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• 2006

DBPs and T&O(taste-and-odor) compounds in drinking water is one of main source to deteriorate water quality. So, these compounds can cause adverse health effects and result in many consumer complaints aesthetically. This experiments carried out to investigate the effect of boiling water on DBPs and T&O compounds in the tap water. THMs and TCM concentration were reduced by 91.3%, 88.9% after 5 min of boiling, respectively. It is certainly, resulted from volatilization of TCM. TCAA concentration decreased when the water was boiled, too. By contrast, the concentration of DCAA was increased with duration time from boiling-point. The reduction of TCAA from the boiled water can be attributed to chemical transformation like decarboxylation. T&O compounds such as geosmin and 2-MIB was effectively removed by boiling of water, resulting in the removal efficiency of 97.1%, 94.4% after 5 min of boiling, respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.1
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• pp.44-47
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• 1988

The present experiments of transient temperature variation and temperature fluctuation were conducted by bead type thermistors in pool boiling without a heat surface. The experimentally obtained conclusion were as follows. (1) The high transient temperature Variatian of 11.64.deg. C for a duration of 0.08 sec and a temperature freguency having a duration of 5.6*10$^{-2}$ sec in a flashing were measured. (2) The highest variation of transient temperature was shown at saturated temperature of 80.deg. C and superheat of 7.9.deg. C. (3) Temperature frequency was found to increase with superheat below 60.deg. C of saturated temperature, but above 60.deg. C it was relative to lower superheat and was found to decrease with higher superheat..

• Journal of ILASS-Korea
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• v.3 no.2
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• pp.24-33
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• 1998

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a kind of flash boiling spray is expected when the back pressure is below the saturation vapor pressure of the butane(0.23MPa at $25^{\circ}C$). An accumulator type pintle injector and its fuel delivery system has been simulated in ruder to give injection pressure, needle lift and rate of fuel injected. The governing equation were solved by finite difference metho. The injection duration was controlled by solenoid valve. Spray behaviors such as a transient spray tip penetration, spray angle and SMD were calculated based on the empirical correlations in case that the back pressure is both above the vapor pressure of the butane and below that of butane. When the back preassure is below the vapor pressure of the fuel, conventional correlation is modified to represent the effect of flash boiling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.7
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• pp.463-468
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• 2017

For transdermal drug delivery, needless injection system is composed of laser and microjet injector. Main mechanism of microjet injector is the laser-induced bubble. Nd:YAG and Er:YAG laser are used as a power source. Laser parameters such as pulse duration and wavelength are considered, which are core parameters to control the bubble motion. The Nd:YAG laser, pulse duration is short than bubble life time making cavitation like bubble while in Er:YAG laser, long pulse duration and high absorption in water drive bubble as a boiling bubble. Detailed motion of bubble and microjet is captured by the high speed camera. So it is observed that microjet characteristics are determined by the bubble behavior. The performance of drug delivery system is evaluated by fluorescent staining of guinea pig skin.

• Child Health Nursing Research
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• v.10 no.1
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• pp.108-116
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• 2004

Purpose: There has been a number of reports on elution of bisphenol-A, an endocrine disrupting chemical, from milk bottles, all concerning the potential health effect of the substance. In this study, we measured the elution of bisphenol-A from milk bottles during boiling-water sterilization, to suggest a safe sterilization method. Method: Through the survey of 200 mothers, 78.5％ of them expressed their concern on the possible harmful effect of bisphenol-A, which might be eluted from the bottles. And it was found that most mothers use boiling-water to sterilize bottles; duration of boiling bottles could be divided into three groups of 3, 5, and 10 minutes. We measured the elution of bisphenol- A from three different brands of bottles, subject to various mode of sterilization found in the survey. Result: In all the measurements, the concentration of the eluted bisphenol-A was in the range of 0.3 - 0.7 ppb, far below 2.5ppm, the level set up by Korea Food ％amp; Drug Administration(KFDA) for a potential harmful effect. Conclusion: Although trace amount of bisphenol -A can be eluted from polycarbonate milk bottles during sterilization, and bottle feeding, the amount is found to be too small to cause any health related impact for infants.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.666-671
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• 1998

Computational fluid dynamics(CFD) code FLUENT[11 was used to simulate the thermal hydraulic processes occuring in conceptual design of the accelerator-driven subcritical reactor(ADSR) liquid lead target. The purpose of the analysis is to investigate the thermal hydraulic characteristics of liquid lead as ADSR target material with various target geometries and injection locations of proton beam. In the calculation analysis, the local temperature of the liquid lead target rises to the boiling temperature very rapidly When the proton beam is injected from the bottom of the target system, the duration time to reach the boiling temperature is longer and the temperature distribution is flatter than other cases.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.60-66
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• 2017

This study was conducted to investigate the influence of bone boiling duration on bovine bone extract supplement quality in terms of growth performance, leg bone length, and blood profile in broilers. A total of twenty ROSS 308 broilers (initial BW of $970{\pm}50g$) were randomly divided into the following 4 treatment groups: CON (basal water), T1 (1 : 1 ratio water to bone extract boiled for six hours), T2 (1 : 1 ratio water to bone extract boiled for 12 hours), and T3 (1 : 1 ratio water to bone extract boiled for 24 hours). The broilers were allowed free access to the source of fluid or diets. Average daily feed intake (ADFI), average daily gain (ADG), and feed efficiency showed no significant differences among treatments during this experiment. However, broilers fed bone extract boiled for six hours showed a tendency for increased ADG to other treatments (p < 0.17). No significant differences were observed in organ weights (liver, spleen, bursa of fabricius) or blood profiles among the treatments during the experiment, but broilers fed bone extract boiled for six hours showed a tendency for decreased cholesterol, triglycerides, and HDL compared to the control diet. In the case of leg bone length, there were significant difference (p < 0.05) on tibia and femur among treatments. It was concluded that the six hour-boiled bone extract supplementation had beneficial effects on growth performance and blood profile of broilers.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.692-698
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• 2012

The chemical conversion pattern of salvianolic acid B (Sal B) in aqueous solution under different boiling conditions was compared. When the duration of boiling was varied, without varying temperature or pressure, the content of chemically converted compounds (CCCs) was mostly increased over time. In addition, under different conditions of temperature and pressure with the same boiling time, the content of a few compounds increased with increasing temperature and pressure. These results confirmed that high temperatures and pressures in boiling alter the final composition of CCCs of Sal B. Therefore, it was suggested that the boiling conditions (time, temperature, and pressure) may be responsible for alteration of biological activities of the compounds. Our investigation of the chemical conversion of compounds contained in foods and medicinal herbs may provide important information in clarifying the biological activity of Sal B containing foods and medicinal herbs.