• Journal of the East Asian Society of Dietary Life
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• v.17 no.1
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• pp.103-109
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• 2007

The optimum conditions for springiness of polymannuronate acorn mook, in which polymannuronate was added to acorn powder, was investigated by the response-surface method(RSM). The fractional factorial design with three variables, i.e. polymannuronate addition, water addition and boiling time, and with three levels revealed that the range of acorn springiness was $0.804{\sim}0.987$. The governing equation was also partially differentiated for boiling time, showing that the optimum manufacturing condition for $90^{\circ}C$ is addition of 2% polymannuronate, addition of 120 mL of water, and 60 minutes of boiling time.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.12
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• pp.938-944
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• 2008

The boiling heat transfer was experimentally investigated for the PF-5052 sprays impacting a square heated test surface in a downward direction. Full cone spray nozzles were employed for the spray cooling experiment, and experiments were made under the test conditions of Q=$3.32{\time}10^{-6}{\sim}\;12.98{\time}10^{-6}m^3/s$, ${\Delta}T_{sub}=5{\sim}25^{\circ}C$. Also, heat transfer measurements were made using the copper block of $10{\time}10mm^2$ test area heated by nine cartridge heater. From the experimental results, correlation between the Nusselt number and Reynolds number based on droplet-flow-rate was developed. The correlation shows good predictions with ${\pm}30$ % error for PF-5052.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.557-561
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• 2019

This study investigated the efficacy of DNA extraction methods for real-time PCR detection of foodborne pathogenic bacteria in livestock manure composts. Livestock manure composts were inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Bacillus cereus and incubated in enrichment broth. For DNA extraction, enriched samples were treated following boiling method, by chloroform, C₁₈ powder, and proteinase K. As a result, 4 species of bacteria were detected by real-time PCR when subjected to boiling for 30 min and treated with proteinase K. These results suggest that detection of foodborne pathogens by real-time PCR from livestock manure composts could be applicable using effective DNA extraction methodology such as the boiling method or proteinase K.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.128-136
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• 2020

In the present experimental study, the effect of water-based iron(III) oxide nanofluid on the MFB(Minimum Film Boiling) point during quenching was investigated. As the highly heated test specimen, the cylindrical stainless steel rod was used, and as the test fluids, the water-based iron(III) oxide nanofluids of 0.001 and 0.01 vol% concentrations were prepared with the pure water. To examine the effect of location in the test specimen, the thermocouples were installed at the bottom and middle of wall, and center in the test specimen. Through a series of experiments, the experimental data about the influences of nanofluid concentrations, the number of repeated experiments, and locations in the test specimen on the reaching time to MFB point, MFBT(Minimum Film Boiling Temperature), and MHF(Minimum Heat Flux) were obtained. As a result, with increasing the concentration of nanofluid and the number of repeated experiments, the reaching time to MFB point was reduced, but the MFBT and MHF were increased. In addition, it was found that the effect of water-based iron(III) oxide nanofluid on the MFB point at the bottom of wall in the test specimen was observed to be greater than that at the middle of wall and center. In the present experimental ranges, as compared with the pure water, the water-based iron(III) oxide nanofluid showed that the maximum reduction of reaching time to MFB point was about 53.6%, and the maximum enhancements of MFBT and MHF were about 31.1% and 73.4%, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.9
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• pp.1239-1246
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• 2000

The objective of this work is to measure space and time resolved wall heat fluxes during nucleate pool boiling of R113/R11 mixtures using a microscale heater array in conjunction with a high speed CCD. The microscale heater array is constructed using VLSI techniques, and consists of 96 serpentine platinum resistance heaters on a transparent quartz substrate. Electronic feedback circuits are used to keep the temperature of each heater at a specified temperature and the variation in heating power required to keep the temperature constant is measured. Heat flux data around an isolated bubble are obtained with triggered CCD images. CCD images are obtained at a rate of 1000frames/second. The heat transfer variation vs. time on the heaters directly around the nucleation site is plotted and correlated with images of the bubble obtainedby using the high speed CCD. For both of the mixture(R11/R113) and pure system(pure R11, pure R113), the wall heat fluxes are presented and compared to find out the qualitative difference between pure and binary mixture nucleate boiling.

• Journal of the Korea Safety Management & Science
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• v.19 no.4
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• pp.317-322
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• 2017

When the heat flux on the heating surface following changing heat condition in the boiling heat transfer system exceeds critical heat flux, the critical heat flux phenomenon is going over to immediately the film boiling area and then it is occurred the physical destruction phenomenon of various heat transfer systems. In order to maximize the safe operation and performance of the heat transfer system, it is essential to improve the CHF(Critical Heat Flux) of the system. Therefore, we have analysis the effect of improving CHF and characteristics of heat transfer following the nanoparticle coating thickness. As the results, copper nanocoating time are increased to CHF, and in case of nano-coatings are increased spray-deposited coating times more than in the fure water; copper nanopowder is increased up to 6.40%. The boiling heat transfer coefficients of the pure water are increased up to 5.79% respectively. Also, the contact angle is decreased and surface roughness is increased when nano-coating time is increasingly going up.

• Journal of the Korean Home Economics Association
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• v.23 no.1
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• pp.25-31
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• 1985

This study designed not only to elucidate free amino acid, fatty acid composition and mineral content in dried alaska pollack but also to examine calcium, magnesium, poassium and sodium contents in its cooking broth according to each boiling time such as 2.5, 5, 10, 20, and 30 minutes. RESULTS : 1. Glutamic acid in dried alaska pollack was the most abundant free amino acid and was followed in order of aspartic acid, lysin, leucine and histidine. They composed of 50.95% of the total amino acid contents. 2. In dried alaska pollack the most abundant fatty acid was palmitic acid. Essential fatty acid content was 26.57% of the total fatty acid. 3. The calcium, magnesium, potassium and sodium contents in dried alaska pollack showed 10.721 mg%, 9.235mg%, 4072.5mg% and 2299.8% respectively. The amount of magnesium and potassium in cooking broth arrived at the highest level when 20 minute boiling was undertaken and the quantities of magnesium and sodium were the highest when 30 minute boiling was made.

• Nuclear Engineering and Technology
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• v.45 no.3
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• pp.335-346
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• 2013

The Critical Heat Flux (CHF) of water with dispersed alumina nanoparticles was measured for the geometry and flow conditions relevant to the In-Vessel Retention (IVR) situation which can occur during core melting sequences in certain advanced Light Water Reactors (LWRs). CHF measurements were conducted in a flow boiling loop featuring a test section designed to be thermal-hydraulically similar to the vessel/insulation gap in the Westinghouse AP1000 plant. The effects of orientation angle, pressure, mass flux, fluid type, boiling time, surface material, and surface state were investigated. Results for water-based nanofluids with alumina nanoparticles (0.001% by volume) on stainless steel surface indicate an average 70% CHF enhancement with a range of 17% to 108% depending on the specific flow conditions expected for IVR. Experiments also indicate that only about thirty minutes of boiling time (which drives nanoparticle deposition) are needed to obtain substantial CHF enhancement with nanofluids.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.4
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• pp.365-379
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• 1994

Pool boiling experiments were carried out to study the effect of electric field on nucleate boiling heat transfer. CFC-11 and its alternative HCFC-123 were used as working fluids. Boiling on both single tube and a bundle of five tubes was investigated. Heat flux varied from 5 to $25kW/m^2$ while the applied voltage changed from 0 to 1kV. The results showed that at low heat flux where boiling was not present or very weak, electric field-induced forced convection helped increase the heat transfer coefficients of CFC-11 and HCFC-123 significantly(4-15 times increase). However, at higher heat flux, nucleate boiling of CFC-11 which is a highly dielectric fluid, was not affected significantly by the application of electric field. In contrast to CFC-11, even at high heat flux, nucleate boiling of CFC-11 which has a relatively larger electric conductivity than CFC-11, was vigorously increased up to 2-4 times. The additional power required to apply the electric field was 1-2% of the total power consumption by the heater. The increase in overall heat transfer coefficient of evaporators with HCFC -123 was about 40%, suggesting a considerable reduction in evaporator size with EHD technique.

• Journal of computational fluids engineering
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• v.16 no.2
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• pp.88-93
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• 2011

A numerical study of subcooled onset of nucleate boiling (ONB) in a micro-channel under pulsed heating using volume of fluids (VOF) model was conducted. The VOF simulation adopting the existing experimental condition is compared to the experimental data. The time to ONB was determined when the void fraction at the microheater surface first appeared. The theoretical superheat for homogeneous nucleation relatively predicts the transient ONB results of convective flow of water well based on local temperature distribution. It was found that once heat load increases at the heater, transient flow boiling starts to occur faster.