• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1353-1358
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• 2004

An experimental study of pool boiling behavior on micro-porous enhanced square heater surfaces immersed in PF5060 is performed. The effects of heater orientation, Subcooling and substrate distance on the pool boiling heat transfer performance for the double heaters were investigated under increasing heat-flux conditions. The boiling performance of micro-porous coated surface was better than that of plain surface. The double heaters with upper substrate of 0.2cm substrate interval have lower boiling performances compared with the results for the double heaters with that of 0.5cm and 1.0cm substrate interval and without the substrate. In comparison to upper heater and below heater with orientation, the upper heater has lower superheat temperature than the below heater due to the bubble sweeping.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.7 s.250
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• pp.646-655
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• 2006

The present research is an experimental study on characteristics of cooling behavior for the adjacent copper blocks with surface roughness or micro-porous coated surface. The experiments were carried out at saturation state or within subcooled states of PF5060. The effects of heater orientation and the intervals between heating surfaces or substrates were investigated under various heat flux conditions. The boiling performance of copper block with micro-porous coated surface was better than that of copper block with surface roughness. It is understood that the bubble sweeping enhances boiling performance for the heaters with inclinations of $\theta=45^{\circ}\;and\;\theta=90^{\circ}$, where as the bubble flattening decreases boiling performance for the heaters with inclinations of $\theta=135^{\circ}\;and\;\theta=180^{\circ}$. In comparison to upper heater and below heater with orientation, the upper heater has lower superheat temperature than the below heater due to the bubble sweeping. It is also found that boiling performance decreases in the case of adjacent double heaters with only 0.2cm substrate interval.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.1022-1035
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• 2016

A double-tube once-through steam generator (DOTSG) consisting of an outer straight tube and an inner helical tube is studied in this work. First, the structure of the DOTSG is optimized by considering two different objective functions. The tube length and the total pressure drop are considered as the first and second objective functions, respectively. Because the DOTSG is divided into the subcooled, boiling, and superheated sections according to the different secondary fluid states, the pitches in the three sections are defined as the optimization variables. A multi-objective optimization model is established and solved by particle swarm optimization. The optimization pitch is small in the subcooled region and superheated region, and large in the boiling region. Considering the availability of the optimum structure at power levels below 100% full power, we propose a new operating scheme that can fix the boundaries between the three heat-transfer sections. The operation scheme is proposed on the basis of data for full power, and the operation parameters are calculated at low power level. The primary inlet and outlet temperatures, as well as flow rate and secondary outlet temperature are changed according to the operation procedure.

• Culinary science and hospitality research
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• v.18 no.5
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• pp.233-242
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• 2012

Jehotang is a cold traditional Korean drink made with honey and several ingredients used in traditional Korean medicine. The ingredients include Fructus mume, Fructus amomi, Fructus tsaoko, Santalum album and honey. In this study, Jehotang and its ingredients were determined through the analysis of antioxidant activity, total phenolic content, ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory activity. In addition, quality characteristics of Jehotang made by a traditional recipe(Yeonmil) and a modern recipe(double boiling and boiling) were also compared in terms of pH, color and sugar content. Total phenolic content of extract from Fructus ammomi was found to be 120.45 mg, and Yeonmil recipe was discovered 152.66 mg equivalent of gallic acid per g of extract. DPPH free radical scavenging activity were Feuctus amomi(93.13%) and Yeonmil recipe(56.44%). The Fructus amomi extract showed the highest ${\alpha}$-glucosidase inhibitory activity(89.51%) at the concentration of $100{\mu}g/mL$. ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory activity of boiled Jehotang were 52.38% and 72.52%, respectively. These results suggest that extract of Fructus amomi has an antioxidant activity and antidiabetic effects. Yeonmil recipe is useful for antioxidant effects more than the others. Also, the double boiling recipe has an excellent antidiabetic effect.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.335-340
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• 2016

This study was conducted to find out the most suitable DNA isolation methods for PCR detection of foodborne pathogens. Four DNA isolation methods including Universal Genomic DNA Extraction Kit (TaKaRa), PrepMan Ultra (Applied Biosystems), boiling method and alkaline lysis method (w/PEG) were tested and compared. The Universal Genomic DNA Extraction kit (TaKaRa) was considered as the more efficient isolation method for Escherichia coli O157:H7 and Staphylococcus aureus in lettuce, fish and beef. Meanwhile to detect the foodborne pathogens directly from foods without enrichment, the four different buffers such as double-distilled water, saline, glycine-saline, glycine-saline with Tween-20 and beef extract were also evaluated. As a result, saline was more suitable buffer for E. coli O157:H7. And double-distilled water was more suitable buffer than saline for S. aureus, respectively

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.932-940
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• 2016

Pool boiling heat transfer of water saturated at atmospheric pressure was investigated experimentally on Cu surfaces with high-temperature, thermally-conductive, microporous coatings (HTCMC). The coatings were created by sintering Cu powders on Cu surfaces in a nitrogen gas environment. A parametric study of the effects of particle size and coating thickness was conducted using three average particle sizes (APSs) of $10{\mu}m$, $25{\mu}m$, and $67{\mu}m$ and various coating thicknesses. It was found that nucleate boiling heat transfer (NBHT) and critical heat flux (CHF) were enhanced significantly for sintered microporous coatings. This is believed to have resulted from the random porous structures that appear to include reentrant type cavities. The maximum NBHT coefficient was measured to be approximately $400kW/m^2k$ with APS $67{\mu}m$ and $296{\mu}m$ coating thicknesses. This value is approximately eight times higher than that of a plain Cu surface. The maximum CHF observed was $2.1MW/m^2$ at APS $67{\mu}m$ and $428{\mu}m$ coating thicknesses, which is approximately double the CHF of a plain Cu surface. The enhancement of NBHT and CHF appeared to increase as the particle size increased in the tested range. However, two larger particle sizes ($25{\mu}m$ and $67{\mu}m$) showed a similar level of enhancement.

• Nuclear Engineering and Technology
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• v.39 no.4
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• pp.313-326
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• 2007

In this paper, an algorithm to reconstruct two orthogonal images into a three-dimensional image is developed in order to measure the bubble size and volume in a two-phase boiling flow. The central-active contour model originally proposed by P. $Szczypi\'{n}ski$ and P. Strumillo is modified to reduce the dependence on the initial reference point and to increase the contour stability. The modified model is then applied to the algorithm to extract the object boundary. This improved central contour model could be applied to obscure objects using a variable threshold value. The extracted boundaries from each image are merged into a three-dimensional image through the developed algorithm. It is shown that the object reconstructed using the developed algorithm is very similar or identical to the real object. Various values such as volume and surface area are calculated for the reconstructed images and the developed algorithm is qualitatively verified using real images from rubber clay experiments and quantitatively verified by simulation using imaginary images. Finally, the developed algorithm is applied to measure the size and volume of vapor bubbles condensing in a subcooled boiling flow.

• Journal of the Korean Society of Food Culture
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• v.24 no.4
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• pp.366-375
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• 2009

This study examined the changes of side dishes in "Eumsikdimibang", "Gyuhapchongseo", "Chosunmusangsinsikyorijebub" over time. As food ingredients, seaweed, red pepper, salted fish, Korean hot pepper paste have been used in "Gyuhapchongseo". The use of cattle by parts, saltwater fish, Chinese cabbage, powdered red pepper, garlic have increased in"Chosunmusangsinsikyorijebub". Cooking techniques, such as the use of wheat flour, a double boiler by the use of steam, and boiling and then roasting cuisine were mostly used in"Eumsikdimibang", but reduced in"Gyuhapchongseo". In "Gyuhapchongseo", the cooking methods are primarily aimed at a positive visual effect, and slices of dried meat seasoned with spices have increased. In"Chosunmusangsinsikyorijebub", various Tang (Guk), the taste of food changed by controlling the gravy content (Gigimi, Chigye, Chorim), meat mixing oil, vegetable and mushroom together to cook and boiling down the main food ingredients to soak the seasoning were increased. Dog-meat steamed dish using the intestine of dog in "Eumsikdimibang" was changed to small intestine of cattle steamed dish in "Gyuhapchongseo". And seasoned dog meat with choncho in "Eumsikdimibang" influenced on beef tail soup with Korean hot pepper paste in "Gyuhapchongseo", and Yookgyejang soup using Korean hot pepper paste in"Chosunmusangsinsikyorijebub". In steamed young chicken, the stuffing such as soybean paste, choncho, welsh onion, leek and flour in "Eumsikdimibang" was changed to minced beef, welsh onion, dropwort and Shiitake mushroom in"Gyuhapchongseo". The steamed young chicken in "Chosunmusangsinsikyorijebub" with stuffing was added to chicken soup using glutinous rice, and ginseng powder. Now, the chicken soup was changed to Samgyetang with glutinous rice, and ginseng. In "Chosunmusangsinsikyorijebub", various vegetable dishes were cooked with beef.

• Culinary science and hospitality research
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• v.21 no.1
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• pp.1-14
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• 2015

Pork belly(PB) and pork shoulder(PS) parts were tested to find out chemical and physical characteristics and sensory evaluation with various cooking methods such as pan heating, boiling, grilling, steaming, charcoal heating, pan heating and double-layer pan filled with phase change material (PCM) cooking. The moisture contents of steamed PB and PS had higher results of 60.2% and 67.2% than other treatments. The highest results of crude fat contents in PB treatments was charcoal roasting as 33.2% (p<0.05) while grilling resulted the highest at 16.0% in the PS (p<0.05). In the crude protein contents, boiling treatment resulted the lowest at 15.4% while steaming was the highest at 18.9% in PB. Also, crude protein content of grilling treatment was 25.2%, a result significantly higher than in other cooking methods in PS. Heating loss, which has a close relationship with water holding capacity, showed the highest result in the charcoal treatment at 40.18% and 39.68% each in the both of PS and PS. In the result of shear force, the lowest result was oven treatment at $2.76kg/cm^2$ in PB (p<0.05) and double-layer pan heating at $3.67kg/cm^2$ in PS (p<0.05). L value in the color test of boiling treatment showed the highest result of 65.16 and 59.72 in the PB and PS respectively (p<0.05), however it scored the lowest of 2.32 in b value in PB (p<0.05). In the 9 point-scale sensory evaluation, grilling treatment showed the highest result of 7.56 in the overall palatability of PB (p<0.05). However, PS in the pan heating which scored 7.22 was the best result while having the lowest score of 5.88 in the boiling treatment (p<0.05).

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.37-43
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• 2008

The research attempted to develop an eco-friendly wood adhesive based on vegetable oil (soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The soybean oils (SBO) were reacted with $O_3$ at the rate of 7.13 g/h for different times, 15 minutes, 30 minutes, 60 minutes, and 120 minutes. Modified chemical structure of the ozonized SBOs were examined by Fourier transform Infrared (FT-IR) spectrum. The FT-IR spectrum of SBO had an absorbance peak at $3010cm^{-1}$ that is the characteristic peak of the unsaturated double bonds. As ozone treatment time increased, the peak of the double bond was disappeared and aldehyde or carboxyl peak appeared at $1700cm^{-1}$. The dry, wet, and cyclic boiling bond strengths of the ozonized SBO mixed with polymeric diphenylmethane-4, 4-diisocyanate (pMDI) were also investigated. In the dry shear test, all strengths met constantly the standard requirement of $7.0kgf/cm^2$ (KS F3101 2006). The bond strengths gradually increased with increasing ozone treatment time. The highest strength showed at 60 minutes ozone treatment and decreased values at 120 minutes. In the cyclic boiling shear test, 30, 60 and 120 minutes exceeded the standard requirement.