• Journal of Science Education
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• v.39 no.1
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• pp.99-112
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• 2015

This study aimed at investigating elementary teachers' stages of concerns and its changes about STEAM education. The participants of this study were 90 elementary school teachers implementing STEAM education in their schools. The Stages of Concern Questionnaire (SoCQ) was administered after the permission was granted by Hall. Data were collected three times from April, June, and December in the year of implementing the exemplary STEAM school. The results indicated that elementary school teachers' concerns toward STEAM education, the differences of the percentile scores of each stages of concerns, showed slightly low. The SoC of teachers in April showed that Awareness(Stage 0) was relatively very high and Consequences(Stage 4) was very low. However, in December, both Awareness(Stage 0) and Management(Stage 3) were very low. In particular, the percentile scores of Consequence(Stage 4) showed the big difference from 54.7 to 74.3. In addition, teachers who took science track in their high schools showed the relatively low score in the stage of Management(Stage 3). Teachers having the degree of Master of Arts presented the relatively low percentile score in the stage of Management(Stage 3). Teachers who majored in STEM related areas at the university presented the relatively low score in the stage of Management(Stage 3). The findings of this exploratory study may provide the useful insights into the integrative approaches of STEAM education.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.23-32
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• 2020

This study investigated the thermal degradation and fading behavior of PTT dyed with vat dye and its dyeing ability. The PTT sample was dyed with vat dye using an acid treatment and pad-steam method to improve the dyeing performance. This method made dye particle nanosize and allowed it to penetrate the polymer material easily. The sample dyed using the pad-steam method showed level dyeing and enhanced dyeing affinity, compared to the batch-dyeing method. The degradation behavior of PTT dyed with vat dye after each heat and UV treatment was examined with the change in tensile strength or K/S value on the sample. The tensile strength and K/S values of the sample dyed with vat dye after the heat and UV treatment decreased with increasing temperature and exposure time. Although they showed high degradation under severe conditions, its rate constant was improved compared to the samples dyed with disperse dye. Consequently, acid treatment and the pad-steam method resulted in the introduction of vat dye on PTT. In addition, the PTT dyed with vat dye showed enhanced thermal and UV resistance because of their high molecular weight and chemical structure for stable adsorption behavior.

• Journal of Science Education
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• v.45 no.3
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• pp.364-378
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• 2021

This study explores the perception of Engineering Design of teachers who have long experience in the Integrated STEAM education. The teachers participating in this study were 12 elementary and secondary teachers with more than five years of experience in the Integrated STEAM Education. The study conducted semi-structured interviews. Interview questions focused on experiences of Integrated STEAM Education and recognition of Engineering Design, whether or not to reflect the curriculum of Engineering Design, and actual cases of Integrated STEAM Education with Engineering Design. As a result of this study, the teachers who participated in this study recognized that 'identification and coexistence of concepts for science, technology, and engineering' about Engineering Design, 'Creative design is possible when creativity is added to Engineering Design', 'Engineering Design is to analyze the economic feasibility and utility of the output created through the creative design process', 'Engineering Design is only for students who choose a career in science and engineering'. Based on this research, We need to establish and present correct concepts for science, technology, and engineering, and make an effort to include Engineering Design for solving scientific problems in the curriculum. In addition, we will have to develop and spread the Integrated STEAM Education program including Engineering Design and apply it in the field. Through this, we will have to find concrete action plans to improve the perception of science and engineering Integrated STEAM programs and Engineering Design among novice teachers and preservice teachers.

• Culinary science and hospitality research
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• v.14 no.1
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• pp.11-20
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• 2008

To establish the optimum formular for processing bread with steam-dried Hizikia fusiformis flour(SHF), it was incorporated into wheat flour by the ratio of 0, 1, 3, 5 and 7% based on a flour weight. Evaluation was performed on the rheological and sensory profile of bread, such as specific loaf volume, water holding capacity(WHC) and height, appearance and Hunter's color value, mechanical texture properties, and sensory value. Increase in the addition of SHF led to the tendency that the expansive force of dough fermentation reduced, and an increase in the textural properties of bread. And cohesiveness, gumminess, and chewiness indicated the tendency of a little reduction as influenced by adding more dried Hizikia fusiformis powder. As for sensory properties and flavor components of the white bread, in case of color and flavor, more than 3% of increase in the addition of the dried Hizikia fusiformis powder led to a drop in preference, and more addition led to a fall in taste and softness. Overall, it was found that adding less than 3% of dried Hizikia fusiformis powder is proper for dough in breadmaking.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.181-188
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• 2012

In this paper, we propose an a strategy using writing based on STEAM Instruction for information gifted students' creative problem-solving. It is needed a complex and dynamic interaction of variety elements for creative problem solving. And it should be provided experience encompassing various disciplines thorough convergence education for leading to the these interactions and developing the ability to solve complex problems. Writing has already been verified educational effects in a variety subjects. And writing gives a positive impact on creative problem solving by helping awareness of the problem and encouraging critical thinking. In addition, writing can be used as an effective tool for improving problem solving based on similarities between problem-solving process. Learners will find algorithm thorough the process analyzing and writing experience with high-tech products like vending machines, mobile phones and can learn naturally the principles of various disciplines used in real life. Furthermore, learners will experience interaction, convergence of various thinking and cultivate creative problem- solving skills.

• Advances in concrete construction
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• v.9 no.5
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• pp.449-457
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• 2020

The influence of subsequent curing on the performance of fly ash contained mortar under steam curing was studied. Mortar samples incorporated with different content (0%, 20%, 50% and 70%) of Class F fly ash under five typical subsequent curing conditions, including standard curing (ZS), water curing(ZW) under 25℃, oven-dry curing (ZD) under 60℃, frozen curing (ZF) under -10℃, and nature curing (ZN) exposed to outdoor environment were implemented. The unsteady chloride diffusion coefficient was measured by rapid chloride migration test (RCM) to analyze the influence of subsequent curing condition on the resistance to chloride penetration of fly ash contained mortar under steam curing. The compressive strength was measured to analyze the mechanical properties. Furthermore, the open porosity, mercury intrusion porosimetry (MIP), x-ray diffraction (XRD) and thermogravimetric analysis (TGA) were examined to investigate the pore characteristics and phase composition of mortar. The results indicate that the resistance to chloride ingress and compressive strength of steam-cured mortar decline with the increase of fly ash incorporated, regardless of the subsequent curing condition. Compared to ZS, ZD and ZF lead to poor resistance to chloride penetration, while ZW and ZN show better performance. Interestingly, under different fly ash contents, the declining order of compressive strength remains ZS>ZW>ZN>ZD>ZF. When the fly ash content is blow 50%, the open porosity grows with increase of fly ash, regardless of the curing conditions are diverse. However, if the replacement amount of fly ash exceeds a certain high proportion (70%), the value of open porosity tends to decrease. Moreover, the main phase composition of the mortar hydration products is similar under different curing conditions, but the declining order of the C-S-H gels and ettringite content is ZS>ZD>ZF. The addition of fly ash could increase the amount of harmless pores at early age.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2699-2708
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• 2020

Helical-coil steam generator (HCSG) technology is a major design candidate for small modular reactors due to its compactness and capability to produce superheated steam with high generation efficiency. In this paper, we investigate the feasibility of the passively autonomous power maneuvering by coupling the 3-D transient multi-physics of a soluble-boron-free (SBF) core with a time-dependent HCSG model. The predictor corrector quasi-static method was used to reduce the cost of the transient 3-D neutronic solution. In the numerical system simulations, the feedwater flow rate to the secondary of the HCSGs is adjusted to extract the demanded power from the primary loop. This varies the coolant temperature at the inlet of the SBF core, which governs the passively autonomous power maneuvering due to the strongly negative coolant reactivity feedback. Here, we simulate a 100-50-100 load-follow operation with a 5%/minute power ramping speed to investigate the feasibility of the passively autonomous load-follow in a 450 MW_th SBF PWR. In addition, the passively autonomous frequency control operation is investigated. The various system models are coupled, and they are solved by an in-house Fortran-95 code. The results of this work demonstrate constant steam temperature in the secondary side and limited variation of the primary coolant temperature. Meanwhile, the variations of the core axial shape index and the core power peaking are sufficiently small.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.2
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• pp.1-10
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• 2018

Structures, systems and components of nuclear power plants should be able to maintain safety even in the event of design-basis accidents such as high-energy line breaks. The high-pressure steam jet ejected from the broken pipe may cause damage to the adjacent structures. The ANSI/ANS 58.2 code has been adopted as a technical standard for evaluating the jet impingement load. Recently, the U.S. NRC pointed out the non-conservativeness of the ANSI/ANS 58.2, because it does not take into account the blast wave effect, dynamic behavior of the jet, and oversimplifies the shape and load characteristics of the supersonic steam jet. Therefore, it is necessary to improve the evaluation method for the high-energy line break accident. In order to evaluate the behavior of supersonic steam jet, an appropriate numerical analysis technique considering compressible flow effect is needed. In this study, numerical analysis methodology for evaluating supersonic jet impingement load was developed and verified. In addition, the conservativeness of the ANSI/ANS 58.2 model was investigated using the numerical analysis methodology. It is estimated that the ANSI jet model does not sufficiently reflect the physical behavior of under-expanded supersonic steam jet and evaluates the jet impingement load lower than CFD analysis result at certain positions.

• Food Engineering Progress
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• v.23 no.2
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• pp.87-93
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• 2019

Temperature distribution studies were performed in steam-air retort to investigate the influence of various processing conditions (come-up time, sterilization temperature, and internal pressure throughout the steam-air retort). Retort temperature data were analyzed for temperature deviations during holding phase, maximum temperature difference between test locations at the beginning and after 1, 3, and 5 min of the holding phase, and box-and-whiskers plots for each location during the holding phase. The results showed that high sterilization temperature led to a more uniform temperature distribution than low sterilization temperature (pasteurization). In pasteurization condition, the temperature stability was slightly increased by increasing pressure during the holding phase. On the other hand, the temperature stability was slightly decreased in high sterilization temperature condition. Programming of the come-up phase did not affect the temperature uniformity. In addition, the slowest cold spot was found at the bottom floor during the holding phase in all conditions. This study determined that the temperature distribution is affected by retort processing conditions, but the steam-air retort needs more validation tests for temperature stability.

• Journal of Life Science
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• v.19 no.1
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• pp.65-74
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• 2009

The objective of this study was to examine the effects of steam flaking treatment of corn grains imported from USA and India on in vitro gas production, microbial growth and contents of aflatoxin $B_1$ and ochratoxin A. Each treatment was composed of total 4 treatments including (1) USCW (US com-whole type), (2) USCF (US corn-flaked type), (3) IDCW (India corn-whole type) and (4) IDCF (India orn-flaked type) with 4 replications $\times$ 6 incubation times (3, 6, 9, 12, 18 and 24 hr). Mycotoxin (aflatoxin $B_1$ & ochratoxin A) contents in test corns tended to increase gradually with increasing logistics periods from the harbor, hopper, silo to processing line. The contents of aflatoxin $B_1$ in India corn (IDCW) and US corn (USCW) were 11.71 and 1.78 ppb, respectively when measured at the hopper. After steam flaking, both contents of aflatoxin $B_1$ in USCW and IDCW were 0.00 ppb. It means that Aspergillus flavus could be decreased by steam flaking. However, this trend was not observed in ochratoxin content. The gas production rate of USA corns (USCW & USCF) was significantly (p<0.05) higher than India corns (IDCW & IDCF), and that of steam flaked corns (USCF & IDCF) was higher $1.5{\sim}2%$ than whole corns (USCW & IDCW) after 3 hr incubation in in vitro experiment. pH value was optimally maintained for microbial growth during whole incubation times with the value of 6.05 to 6.54, and was not significantly different between treatments, but USCF was somewhat lower than other treatments. pH value decreased following 12 hr of incubation but gas production increased rapidly during the same period. In addition, in vitro microbial growth rates also increased with up to 18 hr of incubation period, thereafter experienced a decrease with extended incubation time. In conclusion, US corn was superior to India corn by origin based on the results of in vitro and mycotoxin contents. And steam flaking process of imported corns tended to decrease mycotoxin contents such as aflatoxin $B_1$ and ochratoxin A as well as improve in vitro gas production and microbial growth rates.