• Journal of the Korean Society of Food Culture
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• v.16 no.4
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• pp.323-329
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• 2001

This study was carried out to observe the character change of expanded rice grain for Salyeotgangjung at various gelatinization methods. The expansion and structure change of rice grain was different at conditions of heating methods and gelatinization, respectively. The boiling showed good expansion compared to other heating methods by electric rice-cooker, pressure cooker, and steam cooker. There was not difference in expansion of rice grain between the boiling and the boiling after soaking. Rice grain did greatly expand as the boiling time was extended. But the quality for Salyeotgangjung would be not good because of crack of expanded rice grain surface when the boiling time was too long.

• Nuclear Engineering and Technology
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• v.40 no.6
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• pp.477-488
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• 2008

The objective of the paper is to analyze the thermally induced density wave oscillations in water cooled boiling water reactors. A transient thermal hydraulic model is developed with a characteristics-based implicit finite-difference scheme to solve the nonlinear mass, momentum and energy conservation equations in a time-domain. A two-phase flow was simulated with a one-dimensional homogeneous equilibrium model. The model treats the boundary conditions naturally and takes into account the compressibility effect of the two-phase flow. The axial variation of the heat flux profile can also be handled with the model. Unlike the method of characteristics analysis, the present numerical model is computationally inexpensive in terms of time and works in a Eulerian coordinate system without the loss of accuracy. The model was validated against available benchmarks. The model was extended for the purpose of studying the flow-induced density wave oscillations in forced circulation and natural circulation boiling water reactors. Various parametric studies were undertaken to evaluate the model's performance under different operating conditions. Marginal stability boundaries were drawn for type-I and type-II instabilities in a dimensionless parameter space. The significance of adiabatic riser sections in different boiling reactors was analyzed in detail. The effect of the axial heat flux profile was also investigated for different boiling reactors.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.286-290
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• 1998

The effects of cooking methods and storage time on folate content in spinach were determined by boiling for 1, 2, 3, 4, 5, 10 and 20min in distilled water or by microwave blanching for 20, 40, 60, 80, 100 sec. The folate content of cooked spinach was decreased to 80.7% after 1min boiling, and to 5.5% after 20min boiling. The folate recovered from the cooked spinach and cooking water was 101.1% after 1min, 68.0% after 2min and 51.3% after 3min. The relative folate content leached out of the cooked spinach into the cooking water varied from 20.2% after 1min boiling to 88.8% after 20min boiling. Total folate content of spinach was decreased to 45% by microwave heating for 40sec. However, the spinach cooked by microwave heating retained more folate due to the minimal loss of folate into cooking water. More than 90% of folate content of spinach was retained during 1 to 2 weeks of storage at 4$^{\circ}C$.

• 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.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.77-82
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• 2015

PURPOSES : The purpose of this paper is to evaluate the moisture susceptibility of asphalt mixtures containing developed liquid anti-stripping agents using the boiling water test as a screening test. METHODS : The boiling water test was used to evaluate the moisture susceptibility of asphalt mixtures containing different anti-stripping agents. The tensile strength ratio was calculated to compare the moisture susceptibility of the asphalt mixtures after indirect strength tests were performed. Additionally, image analysis techniques were used to calculate and analyze the quantity of stripped area in the asphalt mixtures. RESULTS : In general, the asphalt mixtures containing anti-stripping agents showed a higher resistance of anti-stripping based on the boiling water test and tensile strength ratio. CONCLUSIONS : The boiling water test can be used to differentiate the resistance of moisture susceptibility of asphalt mixtures, except for asphalt mixtures containing hydrated lime. The boiling water test can be used as a screening test for asphalt mixtures before conducting time consuming and expensive indirect tensile strength tests.

• Korean Journal of Human Ecology
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• v.22 no.3
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• pp.485-492
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• 2013

The temperature changes of dumpling(mandu) during cooking process were examined and the effects of time-temperature and/or time-size interactions on internal temperature were studied. Mandu was purchased from local markets and classified by its weight(small, medium, and large). Boiling, steaming, pan frying, and deep fat frying were adopted. Internal temperature was measured with a food thermometer in every one minute. The internal temperature of mandu increased over time in every cooking process(p<0.05). After three minutes the internal temperature of mandu in boiling, pan frying, and deep fat frying reached over at $74^{\circ}C$, which is high enough temperature to kill the harmful bacteria, but not in steaming. The internal temperature of mandu was significantly affected by cooking time, size, and both in boiling, steaming, and deep fat frying(p<0.05). There were significant differences between the internal and surface temperatures of mandu in the cooking processes except pan frying in three minutes(p<0.05). The results of this study indicate three minutes' cooking of the mandu by boiling, pan frying, and deep fat frying is safe enough to eat. However, longer steaming time is needed in order to reach safe temperature. This study also indicates the cooking time and size of mandu appear to be major factors in determining the internal temperature achieved at $74^{\circ}C$. More research is needed to check time to reach a safe temperature in the cooking process of mandu by steaming.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.218-222
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• 2009

A level-set (LS) method is presented for computation of boiling phenomena which involve liquid-vapor interfaces that evolve, merge and break up in time, the flow and temperature fields influenced by the interfacial motion, and the microlayer that forms between the solid and the vapor phase near the wall. The LS formulation for tracking the phase interfaces is modified to include the effects of phase change on the liquid-vapor interface and contact angle on the liquid-vapor-solid interline. The LS method can calculate an interface curvature accurately by using a smooth distance function. Also, it is straightforward to implement for two-phase flows in complex geometries. The numerical method is applied for analysis of nucleate boiling on a horizontal surface and film boiling on a horizontal cylinder.

• Journal of ILASS-Korea
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• v.25 no.2
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• pp.68-73
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• 2020

In the present study, experiments on the film boiling of liquid droplets on oxidized copper surface was conducted. The shape of pure water droplets was observed, and the evaporation rate of them was measured during the film boiling evaporation process. The droplet of initial volume 16 ~ 30 µl was applied onto the oxidized copper surface heated up to 300 ~ 500℃, then the shape of the droplet was analyzed during the film boiling evaporation. Experimental results showed that there was good correlation between dimensionless volume and dimensionless time. However, a significant difference in evaporation rate for small and large droplets discussed in previous study was not found.

• Nuclear Engineering and Technology
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• v.34 no.4
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• pp.286-300
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• 2002

An algorithm for the sodium boiling model has been developed for calculation of the void reactivity feedback as well as the fuel and cladding temperatures in the KALIMER core after onset of sodium boiling. Modeling of sodium boiling in liquid metal reactors using sodium as a coolant is necessary because of phenomenon difference comparing with that observed generally in light water reactor systems. The applied model to the algorithm is the multiple-bubble slug ejection model. It allows a finite number of bubbles in a channel at any time. Voiding is assumed to result from formation of bubbies that (ill the whole cross section of the coolant channel except for the liquid film left on the cladding surface. The vapor pressure, currently, is assumed to be uniform within a bubble The present study is focused on not only demonstration of the vapor bubble behavior predicted by the developed model, but also confirmation of a qualitative acceptance for the model. As a result, the model can represent important phenomena in the sodium boiling, but it is found that further effort is also needed for its completition.

• Nuclear Engineering and Technology
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• v.41 no.9
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• pp.1205-1214
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• 2009

The critical heat flux (CHF) levels that occurred due to exponential heat inputs for varying periods to a 1.0-mm diameter horizontal cylinder immersed in various liquids were measured to develop an extended database on the effect of high subcoolings for quasi-steady-state and transient maximum heat fluxes. Two main mechanisms of CHF were found. One mechanism is due to the time lag of the hydrodynamic instability (HI) which starts at steady-state CHF upon fully developed nucleate boiling, and the other mechanism is due to the explosive process of heterogeneous spontaneous nucleation (HSN) which occurs at a certain HSN superheat in originally flooded cavities on the cylinder surface. Steady-state CHFs were divided into three regions for lower, intermediate and higher subcooling at pressures resulting from HI, transition and HSN, respectively. HSN consistently occurred in the transient boiling CHF conditions that correspond to a short period. It was also found that the transient boiling CHFs gradually increased, then rapidly decreased and finally increased again as the period became shorter.