• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.17-24
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• 2008

Many problems exist in the current cast in place concrete lining used in domestic tunnel construction. Especially, the crack of tunnel lining brings about a social and economic problem. It has a lot of influence on stability of structure and the fine finish of lining. So enormous repair-work and reinforcement of tunnel lining could occur an running out of government's budget. In our country, there are domestic production enterprises which produce a special pre-cast concrete product, but the technical level of them is still far behind compared to developed countries. Also, optimum steam coring method is important for the production of high quality product. But there is no regulation of steam curing method in our country. This study is to investigate the properties of PC panel according to the variation of steam curing conditions such as presteaming time and rate of temperature rise. The result shows that the optimum presteaming time of steam curing method in PC panel is more than 1 hour and the desirable rate of temperature in curing chamber is about $20^{\circ}C/hr$.

• Culinary science and hospitality research
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• v.18 no.1
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• pp.40-53
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• 2012

The quality changes of vegetables including cucumbers, young pumpkins, carrots, radishes, onions by different cooking methods in $90^{\circ}C$ water, 0.5% NaCl solution, 1.0% NaCl solution and $400^{\circ}C$ superheated steam were investigated. The changes in pH of cooked vegetables were increased. Hunter color system values for L(lightness), a(redness) and b(yellowness) of the vegetables cooked in $400^{\circ}C$ supetbeated steam for 30 seconds were less compared with those in $90^{\circ}C$ water, 0.5% NaCl solution and 1.0% NaCl solution. The microbial growth was inhibited very effectively when the vegetables cooked in $400^{\circ}C$ superheated steam for 30 seconds. After cooked in $90^{\circ}C$ water, 0.5% NaCl solution, 1.0% NaCl solution, $400^{\circ}C$ superheated steam, vitamin C content decreased by different ratio depending on cooking methods and vegetable varieties. Based on the results of the quality changes of cooked vegetables, the superheated steam cooking method showed a positive effect on sterilization and maintaining pH, color, hardness of vegetable tissues, vitamin C content. The data obtained from this study could be utilized as basic information for the optimum conditions of superheated steam cooking to develope HMR(Home Meal Replacement).

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.75-83
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• 2001

The potential of oxygen delignification is a powerful tool to reduce detrimental environmental effects. This study was performed to investigate the effect of steam explosion treatment of chemically treated oak wood on oxygen-alkali pulping. Pulp yield during steam explosion treatment by ${Na_2}{O_3}$-NaOH impregnation was higher than the other impregnation chemicals. Also, NaOH extraction at room temperature after steam explosion treatment improved the kappa number from 140~116 to 90~64. Oxygen-alkali pulping of chemical steam explosion treated woods affected to pulp yields. ${Na_2}{O_3}$-NaOH impregnation was very effective to higher carbohydrate yields at same delignification level. Its carbohydrate yield seemed to be highly related to the effluent pH. Oxygen-alkali pulping after steam explosion treatment of ${Na_2}{O_3}$-NaOH impregnated wood was shown that carbohydrate yield was very high because its effluent pH was increase from natural to mild alkali. Even if oxygen bleaching limit the delignification to 50% in order to avoid unacceptable yield and viscosity losses, oxygen-alkali pulping after steam explosion by ${Na_2}{O_3}$-NaOH impregnation was possible to extend the delignification more than 80%. Considering high pulp yield with lower lignin content from steam explosion treated wood, it might be profitable to end the cook at a high kappa number instead of a low kappa number, and continuously apply the oxygen delignification, in order to better quality pulp.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.761-766
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• 2006

This paper describes a study on the performance of steam ejector by variation of steam pressure. Water temperature is especially important for good qualify of fish in an inland aquafam. In summer season, the water temperature increases above $25^{\circ}C$, but for good quality breeding or fish is the maintenance of optimum aquafam temperature by about $20^{\circ}C$. Therefore it is needed to drop the water temperature to provide suitable conditions of fish growth. There are many kinds of cooling system, in this study using steam ejector. After cooling the water in vacuum tank with the steam ejector then circulate this water to inland aquafam. In this way to minimizes fish stress that it is caused by water temperature. The objective of research confirms the difference of the case which there is no water in the vacuum tank and has water in the vacuum tank. The purpose of this paper is to examine the effects on the performance of steam ejector by variation of steam pressure.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.361-366
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• 2009

This research aims to develop a new drying technology using super-heated steam to reduce the time required for drying ginseng and to enhance its quality. The drying rate of ginseng powder treated with hot-air drying after drying with super-heated steam was about 40% faster than the drying rate of ginseng powder treated with hot-air drying. Minimal difference was found between hot-air drying and hot-air drying after drying with super-heated steam in the general composition of the ginseng powder, such as its crude lipid, crude protein, crude fiber, and ash. Moreover, no difference was found between hot-air drying and hot-air drying after drying with super-heated steam in terms of the ginseng powder's mineral and free sugar contents. The crude saponin contents was 5.43% in the ginseng treated with hot-air drying and 5.4% in the ginseng treated with hot-air drying after drying with super-heated steam. The ginseng powder that was treated with hot-air drying after drying with super-heated steam had a slightly higher redness compared to the ginseng powder that was treated with hot-air drying alone. The number of microorganisms of the ginseng powder treated with hotair drying after drying with super-heated steam showed a reduction of one log cycle in the total bacteria and two log cycles in the yeast molds compared to the ginseng powder treated with hot-air drying alone.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.39-42
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• 2003

Steam Generator has been manufactured by welding process after partial manufacturing of various steel forgings such as shell, head and tube sheet. Usually, these steel forgings are made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced open die forging development status of the large steel forgings which is used for the steam generator of 1,400MW next generation nuclear power plant.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.176-179
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• 2006

Large tubesheet forgings of the steam generator for the 1,400MW nuclear power plant has been developed. Steam Generator is one of the most important structural part for nuclear power plant. It is manufactured by various steel forgings such as shell, head, torus and tubesheet. These steel forgings have been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced the forging process development and manufacturing experience of large tubesheet forgings which will be used for the steam generator of 1,400MW nuclear power plant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.756-759
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• 2003

Steam Generator is one of the most important structural part of nuclear power plant. It is manufactured by welding process of various steel forgings such as shell, head, torus and tube sheet. These steel forgings have been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced open die forging status and investigated forging method of the ultra large steel forgings which is used for the steam generator of 1000MW nuclear power plant. For the same thing. the type of steel forgings consisting steam generator is classified by shell, head, torus and tube sheet. And corresponding forging processes of the steel forgings have been investigated.

• Korean journal of food and cookery science
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• v.29 no.4
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• pp.331-342
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• 2013

The purposes of this study were to identify the actual utilization condition of combi-steam ovens and to evaluate the importance and the satisfaction of dietitians and cooks who used the oven in school foodservice. A survey of 300 schools, 1 dietitian and 1 cook from each school respectively; total 600, was conducted and 202 completed questionnaires were available for the purpose of the statistical evaluation. The main results of this study were summarized as follows: Among the schools, 70.5% set up the oven during 2007~2009, the most commonly used cooking method was 'Baking (87.0%)' and the way of acquiring recipes for the oven was 'from oven manufacturing company (50.0%)'. The advantage of using the oven was 'the convenient use of the oven (63.3%)' and the disadvantage was 'Difficulty of cooking foods evenly (59.8%)'. The degree of importance and satisfaction on twenty six attributes were measured according to type of school, location of school, number of meal service per day, and number of total serving per day. Among quality attributes of importance of the oven utilization, 19/18 characteristics were assessed over 4 point (important) out of 5 scale by dietitians/cooks respectively and in satisfaction 16/18 were over 4 points (satisfied) by dietitians/cooks respectively. When it comes to the most satisfied factor of combi-steam oven, 'Improvement of cooking baked foods' was highest for dietitians (4.60 point) and 'Checking temperature of cooked foods' was for cooks (4.49 point). In overall satisfaction of the oven use, the average score was 4.10 point for dietitians, 3.98 point for cooks out of a 5 point scale. Using the survey results as a base, school foodservices are required to use the combi-steam oven efficiently to serve high quality of meals for students.

• Food Science of Animal Resources
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• v.33 no.1
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• pp.103-108
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• 2013

This study was carried out to observe the effect of superheated steam combined with oven heating on the physico-chemical and sensory properties of chicken meat. Specially, chicken breasts and thighs were heated for 40 min in various heating formulations such as oven heating, superheated steam heating or a combination of two kinds of heating. In the physical properties measurement, the shear force was increased as superheated steam heating time and chicken thighs were higher than chicken breasts in all treatments (p<0.05). The highest level of water holding capacity was solely superheated steam treated chicken for 40 min (p<0.05). The $L^*$ value was decreased but $a^*$ value or $b^*$ value were increased after cooking. Chicken breast exhibited a higher colour value than chicken thigh. Superheated heating was effective to reduce heating loss as 22.64% (p<0.05). However, pH was not different depending on the heating formulation or part of the chicken meat (p>0.05). In the sensory test, the combination of 10 min oven heating and 30 min superheated steam heating was effective to create a good flavour of chicken meat. In this study, an optimum formulation was developed which was a combination of 10 min oven heating and 30 min superheated steam heating. It was more effective to improve the quality of chicken meat than the single heat treatment of chicken meat.