• Title/Summary/Keyword: unit elements

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A CONCEPTUAL STUDY OF PYROPROCESSING FOR RECOVERING ACTINIDES FROM SPENT OXIDE FUELS

  • Yoo, Jae-Hyung;Seo, Chung-Seok;Kim, Eung-Ho;Lee, Han-Soo
    • Nuclear Engineering and Technology
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    • v.40 no.7
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    • pp.581-592
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    • 2008
  • In this study, a conceptual pyroprocess flowsheet has been devised by combining several dry-type unit processes; its applicability as an alternative fuel cycle technology was analyzed. A key point in the evaluation of its applicability to the fuel cycle was the recovery yield of fissile materials from spent fuels as well as the proliferation resistance of the process. The recovery yields of uranium and transuranic elements (TRU) were obtained from a material balance for every unit process composing the whole pyroprocess. The material balances for several elemental groups of interest such as uranium, TRU, rare earth, gaseous fission products, and heat generating elements were calculated on the basis of the knowledge base that is available from domestic and foreign experimental results or technical information presented in open literature. The calculated result of the material balance revealed that uranium and TRU could be recovered at 98.0% and 97.0%, respectively, from a typical PWR spent fuel. Furthermore, the anticipated TRU product was found to emit a non-negligible level of $\gamma$-ray and a significantly higher level of neutrons compared to that of a typical plutonium product obtained from the PUREX process. The results indicate that the product from this conceptual pyroprocessing should be handled in a shielded cell and that this will contribute favorably to retaining proliferation resistance.

Efficiency criteria for optimization of separation cascades for uranium enrichment

  • Sulaberidze, Georgy;Zeng, Shi;Smirnov, Andrey;Bonarev, Anton;Borisevich, Valentin;Jiang, Dongjun
    • Nuclear Engineering and Technology
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    • v.50 no.1
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    • pp.126-131
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    • 2018
  • As it is known, uranium enrichment is carried out on industrial scale by means of multistage separation facilities, i.e., separation cascades in which gas centrifuges (GCs) are connected in series and parallel. Design and construction of these facilities require significant investment. So, the problem of calculation and optimization of cascade working parameters is still relevant today. At the same time, in many cases, the minimum unit cost of a product is related to the cascade having the smallest possible number of separation elements/GCs. Also, in theoretical studies, it is often acceptable to apply as an efficiency criterion the minimum total flow to supply cascade stages instead of the abovementioned minimum unit cost or the number of separation elements. In this article, cascades with working parameter of a single GC changing from stage to stage are optimized by two of the abovementioned performance criteria and are compared. The results obtained allow us to make a conclusion about their differences.

An Analysis of Unit Evaluation Items in Middle School Science Textbooks (중학교 과학 교과서의 단원평가문항 분석)

  • Jo, Changhyun;choi, Wonho
    • Korean Educational Research Journal
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    • v.38 no.1
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    • pp.29-39
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    • 2017
  • This study analyzes the items of acid base and redox unit in the middle school science textbook based on the 2009 revised science curriculum using Bloom's taxonomy of educational objectives. As a result of the analysis, the elements of knowledge area appeared the most in textbook items of all publishing companies, and those elements were less in order of understanding, application, analysis, synthesis and evaluation. And the sub-domain of cognitive domains were not evenly distributed by the publisher. Therefore, schools need to refer to the evaluation items of the textbooks of various publishing companies and use them in class.

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Analysis of research on developmentally supportive care for prematurity in neonatal intensive care unit: a scoping review

  • Lee, Hanna;Park, Ji Hyeon;Cho, Haeryun
    • Child Health Nursing Research
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    • v.28 no.1
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    • pp.9-22
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    • 2022
  • Purpose: The purpose of this study was to identify the gaps in research related to developmentally supportive care in the neonatal intensive care unit (NICU). The ultimate goal was to explore directions of further research on developmentally supportive care for premature patients. Methods: The Arksey and O'Malley scoping review method was used. Articles on developmentally supportive care for preterm infants in the NICU, written in English or Korean, were identified through electronic search engines. A total of 279 papers were identified in the initial search, of which 22 full-text papers were included in this review. Results: Several nursing studies have been published in the past 5 years. The important elements of developmentally supportive care were family-centered care and management of the NICU environment. The primary developmentally supportive care interventions were training programs to promote the care competency of NICU nurses. Conclusion: It is necessary to actively develop comprehensive developmental support interventions that consider the various elements of developmentally supportive care for preterm infants. Additional studies should be done to develop programs that provide direct intervention for premature infant and their families.

A Comparative Analysis of the Kinetic Structure in Lectures on a High School Science (고등학교 공통 과학 강의에서 교사에 따른 역동적 구조의 정량적 비교 분석)

  • Yu, Seung-Geun;Lee, Joon-Sang
    • Journal of The Korean Association For Science Education
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    • v.20 no.4
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    • pp.505-509
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    • 2000
  • The kinetic structure of the content of instructions at the unit of 'heart and circulation' in "the common science", which was respectively given by two teachers majored in biology and two teachers majored in earth science was investigated. Concerning of the mean of the fundamental coefficient (B1), the mean of weighted coefficients (B2) and the progression of instruction (P), T4 (B1, 0.14; B2, 0.82; P; 0.86) teacher showed relatively lower kinetic structure and faster progression than those of the others. The other teachers showed a different level of the kinetic structure and progression: T1(B1, 0.21; B2, 0.86; P; 0.79), T2 (B1, 0.02; B2, 0.85; P; 0.80), and T3 (B1, 0.22; B2, 0.83; P; 0.78). T1 teacher who showed the largest total frequency of verbal elements, the great number of sorts of verbal elements and secondary span, had a higher level of the kinetic structure, but T4 teacher showed the lowest level of total frequency of verbal elements, the great number of sorts of verbal elements and secondary span. The main reason why T4 teacher's instruction achieved a lower level of kinetic structure was estimated that he neglected to reorganize teaching materials and he showed a small number of discourse units. In addition, the unit of 'heart and circulation' was less related to T4 teacher's major and T4 teacher had a shorter teaching experience than those of the others. T4 teacher also took charge of only one class, and this did not allow to instruct repeatedly.

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Development of 'Healthy Couple Relationship' Curriculum in High School Based on Backward Design (백워드 디자인에 기반한 고등학교 '건강한 커플관계' 교육과정(안) 개발)

  • Yu, In-Young;Park, Mi-Jeong
    • Journal of Korean Home Economics Education Association
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    • v.31 no.3
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    • pp.1-21
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    • 2019
  • The purpose of this study is to develop a 'Healthy Couple Relationship' curriculum(plan) for high school home economics based on backward design. In this study, the content elements of 'Healthy Couple Relationship' were extracted through literature analysis, and the need for contents of 'Healthy Couple Relationship' was surveyed in 197 families of home economics teachers and 154 high school students. Based on this, the 'Healthy Couple Relationship' curriculum(plan) of high school home economics curriculum was developed as the backward design, and it was verified by the expert group. The results are as follows: First, when measured on a 5-point Likert scale, the mean scores of the need for content elements of 'Healthy Couple Relationship' was 4.39 for teachers, and 4.02 for students, respectively. The content elements of 'understanding dating violence' was 4.70 for teachers and 4.19 for students. Second, the developed 'Healthy Couple Relationship' curriculum consists of two templates, one for each unit, including curriculum goals, unit composition and unit goals, 8 learning subjects and content elements, evaluation plans including 24 lesson plans. In this study, it is meaningful to propose a "Healthy Couple Relationship" curriculum as an elective course in high school home economics curriculum in preparation for the high school credit system, and to lay the foundations for opening elective courses.

An Analysis on the Changes of Achievement Standards and Inquiry Activities in the 2015 Revised National Elementary School Science Curriculum (2015 개정 초등 과학과 교육과정의 성취 기준과 탐구 활동 변화 분석)

  • Park, Jae-Keun
    • Journal of Korean Elementary Science Education
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    • v.36 no.1
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    • pp.43-60
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    • 2017
  • The purpose of this study was to compare the configuration changes of content elements and inquiry activities between 2009 and 2015 revised national elementary school science curriculum, and to examine the trends in achievement standards. The results of this study were as follows. First, the number of content elements presented in the 2015 revised science curriculum was slightly decreased in comparison to 2009 revised one, but fell short of goal level for revision, that was to cut 20 percent of present achievement standards. The characteristics of changes in achievement standards were to enhance the relation to practical life, to integrate the content elements separated, and to adopt the achievement standard to introduce new concept. Second, the number of inquiry activities presented in the 2015 revised science curriculum was also slightly decreased, and to be linked with the changes of achievement standards. In some cases, the range of inquiry activity was adjusted, or the unit to present it was changed. Teacher should know exactly about the elements to be changed in the 2015 revised national elementary school science curriculum, and it will be needed them to make an efforts in the cause of its smooth application.

The Comparative study on Game Contents Costing by Single Game Element and Multi Game Elements (다중게임요소와 단일게임요소에 의한 게임콘텐츠 원가산정 방법에 관한 비교연구)

  • Lim, Deuk-Soo;Lee, Kook-Chul;Park, Hyun-Ji
    • Journal of Information Technology Applications and Management
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    • v.15 no.1
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    • pp.67-81
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    • 2008
  • Last decade, IT industry in Korea has been developed greatly. The game industry as an international leader has given good value added to its country. Game industry is one of the speedy improved one and it showed over 20% of growth rate from 2002. Most distressings in Game industry, there are no established costing system in spite that there should be in emerging market. In 2004, Game Contents Costing Model using Mission and Event was developed and also the study of Game Elements weight was done in 2005. The cost of Game Contents can be calculated by GEP and its unit price. The study of Game Contents Sizing Model was done in 2005. The costing of Game Contents by single Game Element which represents software which is one of 3 Game Elements-plan, graphic and software-and it is counted by mission and event. If the software element only can not well represent Game Contents volume, we can include plan and graphic elements for Game Contents costing. And we can say above two methods as a costing model of Game Contents. In this paper, these models were tested empirically and proved as usable.

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Analysis on Living Factor and Present Condition of Indoor Thermal Environment in Apartment Units during Winter (아파트의 겨울철 실내온열환경 실태와 생활요인 분석)

  • Choi, Yoon-Jung;Jeong, Youn-Hong
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2008.04a
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    • pp.281-284
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    • 2008
  • The purposes of this study were to make clear the present condition of indoor thermal environment in apartment units and to analyze the relation of the living factors with indoor thermal elements. The field surveys consisted of measurements on physical elements and observations on living factors and interview on resident's subjective responses were carried out in 20 apartment units. The field surveys were carried out during the $January{\sim}March$ 2007. Measuring elements were air temperature, globe temperature, and relative humidity. As results, the averages of indoor temperature each houses were $21.2{\sim}27.2^{\circ}C$, the number of houses exceed the comfort zone were 4. The averages of globe temperature each houses were $21.3{\sim}27.5^{\circ}C$, 6 houses exceeded the comfort zone. The means of relative humidity were $19.5{\sim}58.8%$, relatively dry condition. The clothing value of residents were $0.39{\sim}0.89$ clo(average 0.68 clo). The average of thermal sensation ratings each room were $4.2{\sim}4.8$, 'neutral'$\sim$'slightly warm'. The results of regression analysis on relations of living factors with the thermal elements are as follow; ventilation time(outdoor air exchange), door opening time with balcony, and gas cooker use time had significant effect on indoor temperature.

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Characteristics of Elementary Students' System Thinking in Learning of Water Cycle (물의 순환 학습 상황에서 초등학생의 시스템 사고의 특징)

  • Kim, Bo-Min;Maeng, Seungho
    • Journal of Korean Elementary Science Education
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    • v.39 no.3
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    • pp.412-432
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    • 2020
  • The purpose of this study is to explore the characteristics and the level of fourth grade elementary students' system thinking when they learn the unit of "Journey of Water" in terms of four key elements of system thinking such as understanding of the structure of a system, non-linearity and cyclic features, inter-relations and feedback between system properties, and temporal and invisible aspects of a system. Data included students' worksheets and their responses to a set of Likert-scaled and written assessment items on water cycle. The results showed that the level of students' system thinking did not have any hierarchy in relation to the key elements of water cycle system. In addition, the aspects of individual student's system thinking on its sub-elements were different from each other. Also, there were core ideas of system thinking which were intensively considered according to a given context to understand a complex systemic subject. When students learn water cycle, understanding of non-linearity and inter-relations were weaker compared with other key elements of system thinking. Therefore, if these two factors are taught in advance, it can promote understanding of whole system of water cycle.