• Title/Summary/Keyword: Steam Data

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Steam Explosion Module Development for the MELCOR Code Using TEXAS-V

  • Park I.K.;Kim D.H.;Song J.H.
    • Nuclear Engineering and Technology
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    • v.35 no.4
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    • pp.286-298
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    • 2003
  • A steam explosion module, STX, has been developed using the mechanistic steam explosion analysis code, TEXAS-V, in order to estimate the dynamic load with steam explosion by implementing the module to the integrated safety analysis code, MELCOR. One of the difficulties in using mechanistic steam explosion codes is that they do not have any obvious criteria for defining some uncertain parameters such as triggering timing, triggering magnitude, mesh axial length and mesh cross-sectional area. These parameters have been user decision parts in the past. Steam explosion sample calculations and sensitivity studies on uncertain parameters were conducted to investigate those uncertain parameters. The TEXAS-V simulations were summarized in the format of a look-up table and a linear interpolation technique was adopted to calculate the steam explosion load between the data points in the table. The STX-module merged with MELCOR showed the same results as the original MELCOR and additionally it could estimate the steam explosion load in the reactor cavity.

The Effects of Mentoring Experience in STEAM Classes on Pre-service Mathematics Teachers' Teaching Competency for STEAM Education (STEAM 수업에서의 멘토교사 경험이 예비수학교사들의 STEAM 교수 역량에 미치는 효과)

  • Han, Hyesook
    • Communications of Mathematical Education
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    • v.32 no.1
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    • pp.1-22
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    • 2018
  • The purpose of the study was to examine the effects of mentoring experience in STEAM classes on pre-service mathematics teachers' teaching competency for STEAM education. The study was conducted with 23 pre-service mathematics teachers who participated in the mentoring program affiliated with free learning semester system during one semester. To investigate the changes of pre-service mathematics teachers' teaching competencies for STEAM education and the effects of the mentoring program, pre, post questionnaires, lesson journals, and whole group discussion data were collected. According to the results, pre-service mathematics teachers' competencies for 'knowledge of STEAM education', 'subject matter knowledge', 'teaching and learning methods', and 'learning environments and circumstances' categories were improved significantly after the mentoring program. Especially, some results indicated that pre-service mathematics teachers' teaching experiences in real STEAM classrooms were very helpful for the development of understandings of STEAM education and construction of practical knowledge.

A Theoretical and Experimental Study of the Steam Condensation Effect on the CCFL in Nearly Horizontal Two- phase Flow

  • Chun, Moon-Hyun;Yu, Seon-Oh
    • Nuclear Engineering and Technology
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    • v.31 no.6
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    • pp.618-630
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    • 1999
  • An analytical model that includes the steam condensation effect has been derived and a parametric study has been performed. In addition, a series of experiments were performed and a total of 34 experimental data for the onset of CCFL in nearly horizontal countercurrent two-phase How have been obtained for various flow rates of water. Comparisons of the present CCFL data with slug formation models show that the agreement between the present as well as the existing model and the data is about the same. However, the deviation between the Taitel and Dukler's model predictions and the data is the largest when if j$_{f}$<0.04 m/s. A parametric study of the effect of the steam condensation using the present model shows that, when all local conditions are similar, the model predicted local gas velocities that cause the onset of flooding are slightly lower when condensation occurred. Based on the visual observation and the evaluation of the present work, it has been concluded that the criterion derived for the onset of slug flow can be directly used to predict the onset of inner flooding in nearly horizontal two-phase flow within the experimental ranges of the present work.

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Zricaloy-4 Oxidation Kinetics in High-Pressure High-Temperature Steam (지르칼로이-4의 고압 고온 수증기에서 산화 반응 속도)

  • 박광헌;김규태
    • Journal of the Korean institute of surface engineering
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    • v.34 no.1
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    • pp.17-24
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    • 2001
  • A model for quantifying the effect of steam pressure on the oxide thickness growth was developed based on the experimental data available. First, empirical equations for the thickness estimation of oxide formed in 1 atm steam were made. The oxide growth kinetics turned out to be dependent on 0.4th power of oxidation time. With an assumption that the transition oxide thickness be only a function of temperature, a model for the enhancement of steam pressure on oxide growth was developed. The enhancement coefficient for steam pressure is calculated to be 0.01~0.013 $bar^{-}$. The developed model generally well explains the experimental data.a.

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Gasification reactivity of Chinese Shinwha Coal Chars with Steam (스팀을 이용한 중국산 신화 석탄 촤 가스화 반응에 관한 연구)

  • Kang, Min-Woong;Seo, Dong-Kyun;Kim, Yong-Tak;Hwang, Jung-Ho
    • Journal of the Korean Society of Combustion
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    • v.15 no.1
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    • pp.22-29
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    • 2010
  • In this study, carbon conversion was measured using an electronic mass balance. In a lab scale furnace, each coal sample was pyrolyzed in a nitrogen environment and became coal char, which was then gasified with steam under isothermal conditions. The reactivity of coal char was investigated at various temperatures and steam concentrations. The VRM(volume reaction model), SCM(shrinking core model), and RPM(random pore model) were used to interpret experimental data. For each model the activation energy(Ea), pre-exponential factor (A), and reaction order(n) of the coal char-steam reaction were determined by applying the Arrhenius equation into the data obtained with thermo-gravimetric analysis(TGA). According to this study, it was found that experimental data agreed better with the VRM and SCM for 1,000 and $1,100^{\circ}C$, and the RPM for 1,200 and $1,300^{\circ}C$. The reactivity of chars increased with the increase of gasification temperature. The structure parameter(${\psi}$) of the surface area for the RPM was obtained.

A Study of Factors Influencing Helpfulness of Game Reviews: Analyzing STEAM Game Review Data (게임 유용성 평가에 미치는 요인에 관한 연구: 스팀(STEAM) 게임 리뷰데이터 분석)

  • Kang, Ha-Na;Yong, Hye-Ryeon;Hwang, Hyun-Seok
    • Journal of Korea Game Society
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    • v.17 no.3
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    • pp.33-44
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    • 2017
  • With the development of the Internet environment, various types of online reviews are being generated and exchanged among consumers to share their opinions. In line with this trend, companies are making efforts to analyze online reviews and use the results in various business activities such as marketing, sales, and product development. However, research on online review in industry related to 'Video Game' which is representative experience goods has not been performed enough. Therefore, this study analyzed STEAM community review data using machine learning techniques. We analyzed the factors affecting the opinion of other users' game review. We also propose managerial implications to incease user loyalty and usability.

Analysis of VR Game Trends using Text Mining and Word Cloud -Focusing on STEAM review data- (텍스트마이닝과 워드 클라우드를 활용한 VR 게임 트렌드 분석 -스팀(steam) 리뷰 데이터를 중심으로-)

  • Na, Ji Young
    • Journal of Korea Game Society
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    • v.22 no.1
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    • pp.87-98
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    • 2022
  • With the development of fourth industrial revolution-related technology and increased demands for non-face-to-face services, VR games attract attention. This study collected VR game review data from an online game platform STEAM and analyzed chronical trends using text mining and word cloud analysis. According to the results, experience and perceived cost were major trends from 2016 to 2017, increased demands for FPS and rhythm games were from 2018 to 2019, and story and immersion were from 2020 to 2021. It aims to contribute to expanding the base of VR games by identifying the keywords VR users take interest in by period.

Development of Blade Surface Modeling System Using Point Data (점 데이터를 이용한 블레이드 곡면 모델링 시스템 개발)

  • Kim, Yeoung-Il
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.10
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    • pp.110-115
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    • 2019
  • Stationary and rotating blades can be found in a steam turbine generator and the airfoil shapes of these blades can be defined by point data from an aerodynamic design system. The main design process of blades is composed of two steps: first, the blade surface is modeled with the point data; and then, the section data is generated which contains composite curves with line segments and arcs for CAE of the blade. The surface is modeled by a curve-net defined by the point data, which may be extended to obtain the section data to model the blade. This paper presents methods for automating the above-mentioned steps, which have been implemented in the commercial CAD/CAM system, Unigraphics, with API functions written in C-language. Finally, the proposed methods have been applied to model the blade of a steam turbine generator.

Key Findings from the Artist Project on Aerosol Retention in a Dry Steam Generator

  • Dehbi, Abdelouahab;Suckow, Detlef;Lind, Terttaliisa;Guentay, Salih;Danner, Steffen;Mukin, Roman
    • Nuclear Engineering and Technology
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    • v.48 no.4
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    • pp.870-880
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    • 2016
  • A steam generator tube rupture (SGTR) event with a stuck-open safety relief valve constitutes one of the most serious accident sequences in pressurized water reactors (PWRs) because it may create an open path for radioactive aerosol release into the environment. The release may be mitigated by the deposition of fission product particles on a steam generator's (SG's) dry tubes and structures or by scrubbing in the secondary coolant. However, the absence of empirical data, the complexity of the geometry, and the controlling processes have, until recently, made any quantification of retention difficult to justify. As a result, past risk assessment studies typically took little or no credit for aerosol retention in SGTR sequences. To provide these missing data, the Paul Scherrer Institute (PSI) initiated the Aerosol Trapping In Steam GeneraTor (ARTIST) Project, which aimed to thoroughly investigate various aspects of aerosol removal in the secondary side of a breached steam generator. Between 2003 and 2011, the PSI has led the ARTIST Project, which involved intense collaboration between nearly 20 international partners. This summary paper presents key findings of experimental and analytical work conducted at the PSI within the ARTIST program.

Simulation of Multiple Steam Generator Tube Rupture (SGTR) Event Scenario

  • Seul Kwang Won;Bang Young Seok;Kim In Goo;Yonomoto Taisuke;Anoda Yoshinari
    • Nuclear Engineering and Technology
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    • v.35 no.3
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    • pp.179-190
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    • 2003
  • The multiple steam generator tube rupture (SGTR) event scenario with available safety systems was experimentally and analytically evaluated. The experiment was conducted on the large scaled test facility to simulate the multiple SGTR event and investigate the effectiveness of operator actions. As a result, it indicated that the opening of pressurizer power operated relief valve was significantly effective in quickly terminating the primary-to-secondary break flow even for the 6.5 tubes rupture. In the analysis, the recent version of RELAP5 code was assessed with the test data. It indicated that the calculations agreed well with the measured data and that the plant responses such as the water level and relief valve cycling in the damaged steam generator were reasonably predicted. Finally, sensitivity study on the number of ruptured tubes up to 10 tubes was performed to investigate the coolant release into atmosphere. It indicated that the integrated steam mass released was not significantly varied with the number of ruptured tubes although the damaged steam generator was overfilled for more than 3 tubes rupture. These findings are expected to provide useful information in understanding and evaluating the plant ability to mitigate the consequence of multiple SGTR event.