• 정보교육학회논문지
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• 제15권4호
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• pp.551-560
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• 2011

STEAM 교육은 과학 기술 공학 예술 수학 교과의 연계 지도를 통해 학습자의 과학기술에 대한 흥미와 이해를 높이고 융합적 사고와 문제해결능력을 배양할 수 있도록 주제 중심의 학습 내용으로 교육과정을 재구성하여 가르치는 것이다. 따라서 본 논문에서는 초등학교에서 운영할 수 있는 STEAM 교육과정을 프로젝트 기반 학습 형태로 설계하고 운영에 필요한 교수 학습 자료를 제작하였다. 또한 STEAM 교육에서 IT 기술이 모의실험 도구로 활용될 수 있는 방안을 모색하여 프로젝트 기반 학습의 교육 효과를 높이고자 안드로이드 기반에서 애플리케이션을 개발하였다.

• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.11-20
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• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.68-74
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• 1997

This research was studied dissolving pulp for rayon production, which is not KP, SP methods but steam explosion and oxygen alkali treatment. The variation of characterization in wood cellulose after steam explosion and oxygen alkali treatment this follows. In the oxygen alkali treatment of exploded pine wood, yield of dissolving pulp was lower than steam-exploded oak wood, and we have obtained dissolving pulp that high purity cellulose, but degree of polymerization was inclined to decrease less than 200. In the case of steam-exploded oak wood, degree of polymerization was higher than steam-exploded pine wood but purity of cellulose was lower than its.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.613-616
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• 2007

A pilot scale circulating fluidized bed for refuse derived fuel is developed and constructed in order to demonstrate efficient and safe utilization of waste fuel. The capacity of the facility is 8 steam tons per hour with the steam quality of $450^{\circ}C$ and 38atm. The quantity and the quality of the produced steam is sufficient to produce 1MWe power capacity. The test operation proved the high combustion efficiency of 99% and up. The emissions of NOx, SOx in flue gas are below 100, 60ppm respectively with out any emission control. HCl emissions were above 400ppm at the combustor exit but reduced below 10ppm after scrubber.

• Advances in concrete construction
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• 제11권5호
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• pp.367-374
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• 2021

The present study investigated the effect of the combined carbonation and steam curing on the physicochemical properties and CO₂ uptake of the Portland cement concrete. Four different curing regimes were adopted during the initial 10 h of curing to evaluate the potential of carbonation curing as an alternative to conventional steam curing in the precast concrete industry from environmental and practical viewpoints. Four combinations of carbonation and steam curing conditions were applied as curing regimes to the samples at an early age. The test results indicated that the samples treated with the combined carbonation and steam curing exhibited higher early strength development compared to the other samples, signifying that carbonation curing can reduce the production time of precast concrete. Furthermore, the CO₂ uptake capacity of the samples was calculated and found to be as high as 18% with respect to the mass of the paste samples. Hence, the simultaneous utilization of steam and CO₂ for the fabrication of precast concrete members has the potential to make precast concrete greener and more cost-effective.

• 한국식품조리과학회지
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• 제29권4호
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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.

• 과학교육연구지
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• 제40권2호
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• pp.166-188
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• 2016

이 연구는 과학 수업에서 과학사와 융합인재교육의 활용 실태와 과학사를 활용한 설계 기반의 융합인재교육 수업에 대한 초등교사들의 인식을 분석하는 것이다. 따라서 초등학교 과학 수업에서 과학사와 융합인재교육의 활용 실태와 과학사를 활용한 설계 기반의 융합인재교육 수업에 대한 교육적 가치를 알아보기 위해 설문지는 Shin & Han(2011)과 Lee & Shin(2014)의 연구와 Park et al.(2010)의 연구를 바탕으로 연구문제에 맞게 수정하여 총 20문항의 설문지를 개발하였다. 개발한 설문지는 D시와 G시 지역에 재직하고 있는 201명의 초등교사를 대상으로 설문을 실시하여 그 결과를 분석하였다. 이 연구의 결과 초등교사들은 과학 수업에서 과학사를 적극적으로 다루지 않으며, 주로 학생들에게 간단히 소개하면서 스스로 읽어보게 하였다. 초등교사들은 '충분하지 않은 시간'을 이유로 융합인재교육을 적극적으로 다루고 있지 않으며, '창의적 문제해결력' 에 지도 중점을 두고 있지만 이 단계를 매우 지도하기 어려워하고 있었다. 또한 초등교사은 과학사를 활용한 설계 기반의 융합인재교육수업의 교육적 가치에 대해서 매우 긍정적으로 인식하고 있었다. 특히 과학적 원리와 과거 과학자의 문제해결의 사례를 통해 학생들에게 창의적 설계와 문제해결의 아이디어와 실마리를 제공해 줄 수 있다고 인식하였다. 결론적으로 융합인재교육이 초등학교 현장에서 성공적으로 적용되기 위해서는 이와 같은 초등교사들의 과학사와 융합인재교육의 활용실태에 대한 인식과 과학사를 활용한 설계 기반의 융합인재교육 수업의 교육적 가치에 대한 긍정적인 인식을 바탕으로 향후 보다 구체적인 과학사를 활용한 설계 기반의 융합인재교육 프로그램을 개발하고 적용하여 학교 현장에 보급할 필요가 있겠다.

• 한국수소및신에너지학회논문집
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• 제31권2호
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• pp.169-176
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• 2020

There is a growing interest in hydrogen energy utilization since an alternative energy development has been demanded due to the depletion of fossil fuels. Hydrogen is produced by the reforming reaction of natural gas and biogas, and the electrolysis of water. An solid oxide electrolyte cell (SOEC) is reversible system that generates hydrogen by electrolyzing the superheated steam or producing the electricity from a fuel cell by hydrogen. If the water can be converted into steam by waste heat from other processes it is more efficient for high-temperature electrolysis to convert steam directly. The reasons are based upon the more favorable thermodynamic and electrochemical kinetic conditions for the reaction. In the present study, steam at over 180℃ and 3.4 bars generated from a boiler were converted into superheated steam at over 700℃ and 3 bars using a cylindrical steam superheater as well as the waste heat of the exhaust gas at 900℃ from a solid refuse fuel combustor. Superheated steam at over 700℃ was then supplied to a high-temperature SOEC to increase the hydrogen production efficiency of water electrolysis. Computational fluid dynamics (CFD) analysis was conducted on the effects of the number of 90° elbow connector for piping, insulation types and insulation layers of pipe on the exit temperature using a commercial Fluent simulator. For two pre-heater injection method of steam inlet and ceramic wool insulation of 100 mm thickness, the highest inlet temperature of SOEC was 744℃ at 5.9 bar.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(1)
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• pp.358-363
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• 1995

A study on passive cooling systems for concrete containment of advanced pressurized water reactors has been performed. The proposed passive containment cooling system (PCCS) consist of (1) condenser units located inside containment, (2) a steam condensing pool outside containment at higher elevation, and (3) downcommer/riser piping systems which provide coolant flow paths. During an accident causing high containment pressure and temperature, the steam/air mixture in containment is condensed on the outer surface of condenser tubes transferring the heat to coolant flowing inside tubes. The coolant transfers the heat to the steam condensing pool via natural circulation due to density difference. This PCCS has the following characteristic: (1) applicable to concrete containment system, (2) no limitation in plant capacity expansion, (3) efficient steam condensing mechanism (dropwise or film condensation at the surface of condenser tube), and (4) utilization of a fully passive mechanism. A preliminary conceptual design work has been done based on steady-state assumptions to determine important design parameter including the elevation of components and required heat transfer area of the condenser tube. Assuming a decay power level of 2%, the required heat transfer area for 1,000MWe plant is assessed to be about 2,000 ㎡ (equivalent to 1,600 of 10 m-long, 4-cm-OD tubes) with the relative elevation difference of 38 m between the condenser and steam condensing pool and the riser diameter of 0.62 m.

• Journal of the Korean Wood Science and Technology
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• 제20권4호
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• pp.65-72
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• 1992

Steam defiberated pulp and steam exploded wood(birch chip) were extracted with solvents (hot-water, 1% NaOH, MeOH, hot water, 1% NaOH). The properties of residual fiber were examined for the utilization as ruminants feed. The digestibility is 38% in steam defiberated pulp(10kg /$cm^2$-15min) and 62-77% in exploded wood(17-18kg/$cm^2$-2~10min), respectively. The more steam pressure and time increase, the more the digestibility increase. The sugars obtained from extractives is amount from 7% to 13% in asplund pulp and from 7% to 10% in exploded pulp. The sugars was mainly composed of 70-80% xylose. The digestibility of residual fiber which is extracted with solvents is low than these of original fibers. Considering the yield and digestibility as ruminant feed, exploded pulp under 17kg /$cm^2$ for 10min has the best efficiency. The exploded wood gives 75.3% on yield(O. D. chip) and 48% on the digestibility.