• Journal of Energy Engineering
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• v.22 no.2
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• pp.226-236
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• 2013

The heat distribution and internal flow from the efficiency of actual reformer and specification variation, using the computer simulation and experiment about the steam methane reforming reaction which uses the high temperature reformer. Reaction model from steam refoemer uses the steam response model developed by Xu & Froment.As result we supposed the chemical react Steam Reforming(SR), Water Gas Shift(WGS), and Direct Steam Reforming(DSR) from the inner high temperature reformer dominates the response has dissimilar response. According to result of steam methane reforming reaction exam using high temperature reformer, we figured out when Steam Carbon Ratio(SCR) increase, number of hydrogen yield increases but methane decreases. When comparing and examining between design with one inlet and two inlet, result came out one inlet design is more outstanding at thermal distribution and internal flow, hydrogen yield in one inlet design than two inlet design.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.77-83
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• 2014

The vessel of integral reactor contains its major primary components such as the fuel and core, pumps, steam generators, and a pressurizer, so its size is proportional to the required space for the installation of each component. The steam generators take up the largest volume of internal space of reactor vessel and their volumes is substantial for the overall size of reactor vessel. Reduction of installation space for steam generators can lead to much smaller reactor vessel with resultant decrease of overall cost for the components and related facilities. A printed circuit heat exchanger is one of the compact types of heat exchangers available as an alternative to conventional shell and tube heat exchangers. Its name is derived from the procedure used to manufacture the flat metal plates that form the core of the heat exchanger, which is done by chemical milling. These plates are then stacked and diffusion bonded, converting the plates into a solid metal block containing precisely engineered fluid flow passages. The overall heat transfer area and pressure drops are evaluated for the steam generator based on the concept of the printed circuit heat exchanger in this study. As the printed circuit heat exchanger is known to have much larger heat transfer area density per unit volume, we can expect significantly reduced steam generator compared to former shell and tube type of steam generator. For the introduction of new steam generator, two design requirements are considered: flow area ratio between primary and secondary flow paths, and secondary side parallel channel flow oscillation. The results show that the overall volume of the steam generator can be significantly reduced with printed circuit type of steam generator.

• Journal of the Korean Wood Science and Technology
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• v.23 no.1
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• pp.54-60
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• 1995

This paper reports on the changes of equilibrium moisture contents and specific surface areas of Poplar wood(Populus euramericana) for various steam explosion treatments. Equilibrium moisture contents(EMC) and specific surfaces of steam exploded woods were measured under the moisture adsorption course at 25$^{\circ}C$, and compared with those of other materials and wood meals. The EMCs of steam exploded wood meal were 1~5% less in comparison with that of wood meal. In the case of delignified steam exploded wood meal and delignified wood meal, the same tendency was appeared too. But absolute values of EMCs for delignified wood meals were larger than those of the wood meal. For the changes of EMC by the steam exploded conditions, the EMC decreased with the increase of the steam explosion pressure. On the other hand, specific surface areas were calculated from BET plots based on amounts of monomolecular vapor adsorption of various wood meals. Specific surface areas of the wood meal and delignified wood meal were 90~145, 34~90($m^2/g$) respectively, and which were greater in comparison with those of steam exploded wood meals and delignified steam exploded wood meals. From these results, it is considered that the amount of water vapor adsorption was decreased by the increase of the crystallinity, effect of heat treatment, and coating by melted lignin in during the steam explosion.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.543-554
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• 2014

Natural plant extract has been the subject of intense research aiming in elucidating the underlying mechanisms of their chemopreventive effects upon various forms of human cancers. The objective of our study was to evaluate the natural antioxidants and anticancer agent potential of Phyllostachys. The chemical composition of steam extract from Phyllostachys was carried out using GC-MS. The steam extract of Phyllostachys was dominated by monoterpenes (62.96% - 71.36%) and sesquiterpenes (23.58% - 33.13%) as the main compounds. The antioxidant activities of the steam extract was determined using a DPPH scavenging and hydrogen peroxide scavenging activity test systems. Furthermore, the amounts of total phenolics in steam extract were determined spectrometrically The steam extract of P. pubescens and P. bambusoides were presented the high activity (69.4% and 64.0%, respectively.). The steam extract from Pyllostachys species showed a hydrogen peroxide scavenging activity of approximately 50.4% - 54.6% when compared to that of the standard gallic acid. The anticancer activities of steam extract were determined using a MTT assay. Assessment of the cytotoxic effect of the steam extract on PC-3 cells showed that the P. bambusoides (20.85%) and P. pubescens (20.41%) were superior in induced cytotoxicity compared with the steam extract of P. nigra var. henonis (1.15%). Findings from this study indicated that steam extract of P. bambusoides and P. pubescens possessed potential as medicinal drug especially in prostate cancer treatment.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.851-858
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• 2002

This study was conducted to determine effects of whole (intact), coarsely-ground (4 mm), finely-ground (1 mm), steam-flaked and steam-flaked-ground (1 mm) corns on in vitro and in situ DM digestibilities and also in vitro fermentation characteristics. After 48 h incubation, in vitro dry matter digestibilities of whole, steam-flaked, coarsely-ground, steam-flaked-ground, and finely-ground corns were 6.79, 61.68, 76.48, 85.72 and 90.31%, respectively. Steam-flaked-ground corn showed the highest digestibility until 24 h incubation (p<0.01). After 48 h incubation, pH of whole corn decreased with a small range. However the values of pH of other media significantly decreased (p<0.01). The gas productions of finely-ground and steam-flaked-ground corns were higher than those of the other corns (p<0.01). After 24 h incubation, $NH_3$-N concentration of finely-ground and steam-flaked-ground corns increased rapidly. Total VFA was the highest in finely-ground corn, followed by steam-flaked-ground, steam-flaked, coarsely-ground and whole corns. Incorporating steam-flaked corn resulted in the highest propionate concentration (p<0.01) and the lowest acetate : propionate value (p<0.05). Finely-ground corn showed the highest in situ DM digestibility throughout the incubation period (p<0.01), followed by coarsely-ground, steam-flaked and whole corns, respectively. Overall, DM of whole corn was merely digested in vitro as well as in situ.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.2
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• pp.14-20
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• 2012

Full load rejection capability of nuclear power plant depends primarily on steam dump capacity (SDCAP) and steam generator level control capability. Recently, Ulchin Units 1&2 have performed stretched power uprate (SPU) and replacement steam generator (RSG) projects, which increase the power by 4.5 percent. They change major design or operating parameters and especially reduces steam dump capacity at full power due to increase of the steam flow. The reduction of SDC after SPU results in degradation of heat removal capability in full load rejection transients. Therefore, we should perform evaluation to determine whether reactor trips occur in large load rejection transients. Uchin Units 1&2 have experienced full load rejection (FLR) three times from 2004 to 2010. Operating data from the plant occurrence of FLR at Ulchin Units 1&2 showed that steam generator (SG) level transients were limiting in point of reactor trip. However the plant had never reached reactor trip in the FLR and successfully continued in house load operation. The parameters and setpoints for the SG will be changed if the SG is replaced. Therefore, we evaluated the appropriateness of steam dump, main feedwater and steam generator water level control system preventing the plant from reactor trip in case of FLR by the parameter sensitivity study whether SG water level operated smoothly after SPU and RSG projects.

• Journal of Science Education
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• v.37 no.2
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• pp.338-347
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• 2013

The purposes of this study were to develop the activity based STEAM education program and to investigate the effects of the developed program on students' interest in science learning. The program was applied to 7th grade science club. This study was planned to single group pre-post test design. Test tool was the questionnaire of interest on science learning. In the results of t-test, there was statistically significant difference on the pretest and posttest of interest in science learning. Also there was significant difference on attitude toward science, recognition and strategy on science learning that were subdomains of interest on science learning. The results indicated that activity-based STEAM education program was effective in improving students' interest in science learning. In future, studies should be conducted that examine the effect of STEAM program on creativity and problem-solving activity. Therefore studies on the effectiveness of activity-based STEAM education programs should be made continuously.

• Resources Recycling
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• v.18 no.2
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• pp.51-55
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• 2009

Sawdust and sewage sludge and PE gasification by high temperature steam of Brown gas have been performed in this study. Steam/carbon ratio has been changed from 1 to 5 and the effect of steam/carbon ratio on the produced gas concentrations, gasification rate and tar generation has been determined. Also, the temperature distribution in the gasification reactor has been studied. Highest combustible content in the produced gas is around 70vol% and $H_2$ shows highest content among the combustible compounds. However, the heating value of the produced gas and tar content have been reduced with increasing steam/carbon ratio.

• Korean Journal of Community Nutrition
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• v.27 no.5
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• pp.361-372
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• 2022

Objectives: The purpose of this study was to explore the effectiveness of the STEAM (Science, Technology, Engineering, Arts, and Mathematics) education program on the use of specific food groups in improving nutrition-related knowledge and attitude, dietary behavior, creative problem solving, and STEAM attitude. Methods: We selected two classes at a kindergarten in Jeollabuk-do, South Korea. A total of 44 kindergarteners from the two classrooms participated in this study. The experimental group and the control group were formed with 22 students each. The experimental group attended 11 STEAM classes on the use of the grain, fruit, and milk food groups. First, we performed the paired t-test to examine changes from pre-to-post classes for both groups. Then, we used ANCOVA to compare post-test scores between the experimental and control groups with the adjustment of pre-test scores. Results: The results demonstrate that the STEAM education program on the use of the food groups significantly improved (1) nutrition-related knowledge and attitude, and dietary behavior (P < 0.001), (2) creative problem solving (P < 0.001), and (3) STEAM attitude (P < 0.001) in the intervention group when compared with the control group. Conclusions: The STEAM education program on the use of food groups is effective in enhancing nutrition knowledge and attitude, dietary behavior, creative problem solving, and STEAM attitudes among kindergarten students.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.738-743
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• 2001

A computer program, capable of performing thermal design analysis of the triple pressure bottoming system of combined cycle power plants, was developed. The program is based on thermal analysis of the heat recovery steam generator and estimation of its size and steam turbine power. The program is applicable to various parametric analyses including optimized design calculation. This paper presents examples of analysis results for the effects of arrangement of heat exchanger units, steam pressures and deaerating sources on design performance indices such as steam turbine power and the size of heat recovery steam generator.