• Journal of Engineering Education Research
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• v.23 no.2
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• pp.14-23
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• 2020

Based on the constructivist learning environments model and the learner-centered psychological principles, STEAM education program with the theme of eliminating smog was developed. Through the program, senior elementary school students will learn and apply the convergence knowledge of science, technology, engineering, arts and mathematics such as the human body's respiratory system (S), immune system (S), big data (M, T), computer programming(M), and aduino sensor utilization (E) directly to solve the problem. After expert validity testing, we found that developed program meet the standards of STEAM education program development and can develop creative thinking skills to find and solve problems in students' daily lives. In addition, this study is meaningful in providing a reference example for the development of STEAM education programs that enhance convergence knowledge in the future.

• The KSFM Journal of Fluid Machinery
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• v.18 no.6
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• pp.19-26
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• 2015

The present paper presented and applied an exergy analysis method to evaluate the magnitudes and the locations of exergy losses in the conventional desuperheating and depressurizing process of high pressure and temperature steam delivery system. In addition, for the reduction of exergy losses occurred in conventional process, the present study proposed new alternative processes in which the pressure reducing valve and the desuperheater of conventional process are substituted with steam turbine and heat exchanger, and their effects on exergy loss reduction and exergy efficiency improvement are theoretically investigated and compared. From the present analysis results, the total exergy loss caused in conventional desuperheating and depressurizing process accounted for 66.5% of exergy input and 85% of the total exergy loss was due to the mixing between steam and cold water(e.g desuperheating). However, it was shown from the present analysis results that the present alternative processes can additionally reduce exergy loss by maximum 92.7% of the total exergy loss in conventional process, and can also produce additional and useful energy, the electricity of 220.6 kWh and the heat of 54.3 MJ/hr.

• Journal of Hydrogen and New Energy
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• v.25 no.4
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• pp.364-377
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• 2014

The performances of a coupled reactor in which a steam reformer and a catalytic combustor were mounted simultaneously had been investigated and compared. The combustible offgas exhausted from the anode of SOFC and MCFC were utilized as heat sources for the endothermic steam methane reforming. The catalytic combustion was used in order to burn the combustible offgas. Thermal energy released by the catalytic combustion is directly transferred to the reformer surrounding the combustor. The various operational conditions such as fuel utilization rate, steam to carbon ratio, amount of catalysts, fuel cell loads were changed. And operating variables were comprehensively identified by sensitivity analysis. The fundamental results from this experimental study show the potential abilities of the coupled reactor. Therefore the results will be of help to design and manufacture the more better coupled reactor in the future.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.30-36
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• 1994

Steam explosion process is one of the most efficient, pretreatment method for the utilization of lignocellulosic biomass. The carbxymethyl-cellulose(CMC) was prepared with steam exploded wood(EXW), pine(Pinus densiflora) and oak(Quercus mongolica), by standard method using isopropyl alcohol and monochloroacetic acid. The range of water solubility of carboxymethylated pine exploded wood was 45.2~66.8 % and those of oak was 60.7~84.7 %. The degree of substitution(D.S) of carboxymethylated pine exploded wood was 0.11~0.33 and oak exploded wood was 0.48~0.76. The color of carboxymethylated pine and oak exploded wood was brown-black. When carboxymethylated EXW was purified by sulfuric acid, the yield of carboxymethylated wood was lower than non-treated one. However, the color was still brown-black although after delignification. In carboxymethylated EXM prepared after delignification, the water solubility and degree of substitution(D.S) of pine were 81.4~95.9 % and 0.71~0.79, and those of oak were 76.2~89.5 % and 0.79~1.05. The values were higher than non-treated. The degree of substitution of purified carboxymethylated wood prepared with delignified EXM, pine and oak were 0.50~0.71 and 0.70~0.88. The color of carboxymethylated wood was white. In carboxymethylated wood preparde after delignification of EXM, swelling ratio and water retention value of pine were 95.9~96.5 and 580.0~751.2, those of oak were 76.2~89.5 and 124.3~307.6.

• Journal of The Korean Association of Information Education
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• v.15 no.4
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• pp.543-550
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• 2011

STEAM education is a topic-based curriculum to integrate the concepts into other subjects such as science, technology, engineering, art and mathematics in order to improve the students' interesting, understanding, integrated thinking and problem solving ability. In this paper, we designed STEAM curriculum in the form of Project-based Learning and developed the material for elementary students. We also developed the android-based application through searching for a utilization of IT simulation for enhancement the students' Project-based Learning effect.

• Journal of Science Education
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• v.36 no.2
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• pp.381-393
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• 2012

This study was analyzed that what kind of elements for STEAM, except scientific commonsense, are contained in 2009 revised chemistry textbooks I for high school students. So first, elements of STEAM in textbooks were examined by following three sections; by publishing company, each unit and area of textbook. For reference, new sub-elements of STEAM were set because existing elements of STEAM is incongruent with current textbooks. As a result, most chemistry textbooks included elements of STEAM properly for inter-related learning with the other fields. Every textbook had its unique learning methods for utilizing elements of STEAM and they were unified as one way. Depending on textbooks, learning methods were little bit different from the others. Also, detailed elements of STEAM contained in textbooks were classified just 14 types. And they were even focused on a few elements according to sort of textbook. Thus, it seemed that there was a certain limitation of current education of STEAM in chemistry Field. By the unit, according to the curriculum, contained elements of STEAM were different. Almost all elements of STEAM were located in I section. Consequently, it is difficult to include elements of STEAM if mathematics or history were not existed in curriculum. Lastly, by the area, most of all elements of STEAM were included in reference section. Almost all elements of STEAM were focused on art and culture. Thus, STEAM was used for utilization about chemical knowledge in substance. Otherwise, convergence training for approach method was not enough in chemical knowledge.

• Journal of Korean Society of Water and Wastewater
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• v.38 no.3
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• pp.155-164
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• 2024

There are two primary sludge drying methods such as the direct heating microwave method and the indirect heating steam one. In this study, the drying treatment facility at sewage treatment plant A applied both of these drying methods. The research aimed to investigate the optimal operation approach for the drying facility, considering the input sludge and the moisture content data after the drying process. Moisture content and removal rate data were executed at the research facility from January 2016 to December 2018. First, the microwave, a direct heating drying method, performed intensive drying only on the outer surface of the sludge by directly applying heat to the sludge using far infrared rays, so effective sludge drying was not achieved. On the other hand, the steam method of the indirect heating method used steam from a gas boiler to maximize the utilization of the heat transfer area and reduce energy of the dryer, resulting in an effective sludge drying efficiency. The sludge moisture content brought into the sludge drying facility was about 80%, but the moisture content of the sludge that went through the drying facility was less than 10% of the design standard. Therefore, the steam method of the indirect heating method is more effective than the microwave method of the previous direct heating method and is more effective for maintenance It has proven that it is an efficient method of operating construction facilities.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.183-189
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• 1994

Two experiments were made. In experiment 1, four diets containing 0, 5, 15 and 25% washed seaweed meal were prepared to study the effects of incorporating seaweed meal instead of equivalent amounts of berseem leaf meal in fish feeds on growth performance and feed utilization of common carp. The results showed that average daily gain (ADG), specific growth rate (SGR%), dry matter (DM) and ether extract (EE) of the carcasses were decreased (p<0.05) with the increasing level of seaweed meal in the feeds. Inclusion of 5% seaweed meal in the diet gave the best feed conversion ratio (FCR) among all diets, however, protein productive value (PPV) and energy utilization (EU) were decreased (p<0.05) with increasing level of seaweed meal in the diet. In experiment 2, washed seaweed meal was either steam cooked or sprayed with NaOH (0.5% or 1% NaOH) and incorporated in the diets at the level of 25% instead of equivalent amount of berseem leaf meal. The results showed that steam cooked seaweed gave the best (p<0.05) growth performance, FCR and protein efficiency ratios, PER and PPV, for other treatments in descending order were NaOH treated seaweed, washed seaweed and unwashed seaweed.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1237-1242
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• 2008

A study on waste heat utilization of melted slags at pyorlysis, gasification and melting system was performed. Researchers studied heat balance of substances that flow and flow out to the system which is consisted of melting furnace, combustion chamber, and waste heat boiler, then they calculated melting slags' quantity of heat by the first law of thermodynamics. If they use water cursh pit outflow which is gotten by quenching of melting slag as a energy for heating and cooling system, steam of waste heat boiler would be delivered to a steam turbine, making energy, then they will get 67,671,000 won of profit a year. It will take 3 years to repossess the cost that they invested for building it. And, if we predict durability of trash burner is 20 years, we will get approximately 1,150,407,000 won of profits in 17 years without the period when we repossess the building costs.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.30-36
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• 1993

Wood chips of oak (Quercus mongolica) and larch (Larix leptolepis) were treated with a relatively low pressure steam(10~20 kg/$cm^2$) for 10~20 min (first-stage),and then increased pressure up to 30kg/$cm^2$ for 30 second (second-stage), and steam pressure was released intentionally to air. Main components of exploded wood were separated with 1% NaOH and hot water-methanol. In this work, the more effective low pressure explosion condition and separation method of wood main component were investigated. The results can be summarized as follows; 1. The yields of exploded wood were generally decreased with increasing steam pressure and reaction time. 2. The proper condition of steam explosion in low pressure for the separation of wood main components was 15kg/$cm^2$-10 min, in oak wood and 20kg/$cm^2$-10 min., then 30kg/$cm^2$-0.5 min, in larch wood. 3. The 23% of elude hemicellulose was obtained from the exploded oak wood which was treated with optimal condition. 4. In the case of hot water-methanol extraction, the ratio of delignification was 14~23% in the exploded larch wood and 42~55% in the exploded oak wood. 5. The methanol was more effective than 1% sodium hydroxide solution for extraction of lignin from exploded wood.