• Title/Summary/Keyword: Time-History analysis

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Development of On-line Life Monitoring System Software for High-temperature Components of Power Boilers (보일러 고온요소의 수명 감시시스템 소프트웨어 개발)

  • 윤필기;정동관;윤기봉
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1999.05a
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    • pp.171-176
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    • 1999
  • Nondestructive inspection and accompanying life analysis based on fracture mechanics were the major conventional methods for evaluating remaining life of critical high temperature components in power plants. By using these conventional methods, it has been difficult to perform in-service inspection for life prediction. Also, quantitative damage evaluation due to unexpected abrupt changes in operating temperature was almost impossible. Thus, many efforts have been made for evaluating remaining life during operation of the plants and predicting real-time life usage values based on the shape of structures, operating history, and material properties. In this study, a core software for on-line life monitoring system which carries out real-time life evaluation of a critical component in power boiler(high temperature steam headers) is developed. The software is capable of evaluating creep and fatigue life usage from the real-time stress data calculated by using temperature/stress transfer Green functions derived for the specific headers and by counting transient cycles. The major benefits of the developed software lie in determining future operating schedule, inspection interval, and replacement plan by monitoring real-time life usage based on prior operating history.

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Time-Dependent Nonlinear Analysis of Cable-Supported Prestressed Concrete Frames (케이블로 지지된 PC뼈대의 시간의존적 비선형 해석)

  • Lee, Jae Seok;Kang, Young Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4
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    • pp.33-47
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    • 1992
  • A study for the material and geometric nonlinear analysis of segmentally erected cable-supported prestressed concrete plane frames including the time-dependent effects due to load history, creep, shrinkage, aging of concrete, and relaxation of prestressing steel and cable is presented. Updated Lagrangian formulation is used to account for the nonlinear behavior of the structure. For the time-dependent analysis. the time domain is divided into a discrete number of intervals, and a step-forward integration is performed as the solution progresses in the time domain. At each time step. a nonlinear finite element analysis is performed in the space domain. Segmental erection methods are implemented by providing the capability to change the configuration of the structure at any time step of the solution. The computer program CFRAME is developed and a series of numerical examples are presented to study the validity of the program.

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A Historical Research on Correlation between the Standard of Beauty and Spatial Characteristics - Focusing on Greek.Rome and Renaissance - (미의 기준과 공간 특성의 상관관계에 대한 역사적 연구 - 그리스.로마 및 르네상스를 중심으로 -)

  • Lee, Chul-Jae
    • Korean Institute of Interior Design Journal
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    • v.19 no.6
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    • pp.141-149
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    • 2010
  • This thesis is designed to take a close look into the characteristics of architectural space through the standard of beauty, which has been created apart from our desires at certain cultural or historical periods of time. It will try to construct the outline of conception about the beauty throughout many centuries. First of all, contents of the research will focus on the aspects, which people have been considering as beauty eversince the ancient time without having any assumptions on its concept. For example, if the beauty of art has been accepted by the theories of modern aesthetics while degrading the beauty of nature, its value could have possibly been much more appreciated. The standard of beauty has been going through the process of change in such history of mankind. The general standard of beauty, which was established in the ancient time was the proportion and harmony between many elements. Afterwards, beauty was expressed as colors and light in medieval times. Expression of beauty using ugly features such as monsters or demons also existed at the time. Beauty has been periodically developing from supernatural to gracious, rational, noble, romantic, religious, mechanical, and today's media. The concept of beauty established from the above has been appearing throughout various culture such as dress and decoration at the given period of time. It would later affect the formation of space as well as decoration for architectures and styles. It will be analyzed throughout the five design elements; style, composition, materials, components, and form. The thesis would like to find the spatial order of beauty from the result of the analysis. The analysis will examine the possibility for which the recomposition of beauty will be provided as a design process for the new era. The Greek beauty represents a shape. The shape represents proportion and the proportion represents given numbers. However, beauty is being expressed by the opposite process at the present time. In other words, computers will arrange the numbers, which would formalize the proportion between the numbers. Beauty would be presented when the shape is presented as certain forms.

May 18 Democratic Uprising and Experiences of Nursing Activities in the Gwangju Area (5.18민주화운동과 광주 지역에서의 간호활동 경험)

  • Yang, Ya Ki
    • Journal of Korean Academy of Nursing Administration
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    • v.20 no.1
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    • pp.82-94
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    • 2014
  • Purpose: This study was conducted to define the experiences of nursing activities in Gwangju area during the May 18 (5 18) Democratic Uprising over 30 years ago. Methods: Data were collected in 2010 and 2011 through individual in-depth interviews. Ten nurses who worked in general hospitals in the Gwangju area during the 5 18 Democratic Uprising were interviewed using open-ended questions. Each interview lasted about 2~3 hours. Verbatim transcripts were analyzed using Van Kaam's method of phenomenological analysis. Results: Four categories emerged from the analysis: anxiety about the incident which was experienced for the first time; progress of the 5 18 events and relationship to participants; changes in nursing environment; retrospection and wishes related to the 5 18 incident. Conclusion: This oral history study revealed more clearly of the experiences of nursing activities in the Gwangju area during the 5 18 Democratic Uprising. The data may provide a basis for writing history nursing in the community, and can be a basis for guidelines covering nursing care in crisis.

Reproduction of Traditionally-Refining Acupuncture Needle and Analysis of Surface-chemical Properties (전통 연침법(鍊鍼法)의 재현 및 침(鍼) 표면 변화의 분석)

  • Lee, Seung-Taek;Yu, Jeong-Ung;Kim, Ik-Jin;Cha, Wung-Seok
    • The Journal of Korean Medical History
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    • v.26 no.2
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    • pp.135-148
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    • 2013
  • This study analyzed surface-chemical transitions in manufacturing process of traditional acupuncture as proposed method by Dongeuibogam. The manufacturing process of traditional acupuncture from a used iron for a long time was divided by primary medicinal herbs treatment, secondary medicinal herbs treatment and tertiary treatment using by dog meat. The traditional acupuncture research process was measured according to the characteristics and changes of the specimens at each processing step of the manufacturing process. The following devices were used to Surface analysis. Scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffraction analyzer (XRD). As a result, medicinal herbs removed impurities on the surface and raised the antibacterial effect in the manufacturing process of traditional acupuncture. Furthermore, the ingredients of medicinal herbs were coated on the surface of the iron. Dog meat influenced to prevent surface corrosion, reduce friction when the acupuncture was inserted. Although the process empirically obtained, a glimpse of the wisdom of our ancestors was revealed. These ancestral wisdom can be expected to apply today, when used in manufacturing process of a modern stainless steel acupuncture to compensate for the defective part.

Verification and validation of isotope inventory prediction for back-end cycle management using two-step method

  • Jang, Jaerim;Ebiwonjumi, Bamidele;Kim, Wonkyeong;Cherezov, Alexey;Park, Jinsu;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.53 no.7
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    • pp.2104-2125
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    • 2021
  • This paper presents the verification and validation (V&V) of a calculation module for isotope inventory prediction to control the back-end cycle of spent nuclear fuel (SNF). The calculation method presented herein was implemented in a two-step code system of a lattice code STREAM and a nodal diffusion code RAST-K. STREAM generates a cross section and provides the number density information using branch/history depletion branch calculations, whereas RAST-K supplies the power history and three history indices (boron concentration, moderator temperature, and fuel temperature). As its primary feature, this method can directly consider three-dimensional core simulation conditions using history indices of the operating conditions. Therefore, this method reduces the computation time by avoiding a recalculation of the fuel depletion. The module for isotope inventory calculates the number densities using the Lagrange interpolation method and power history correction factors, which are applied to correct the effects of the decay and fission products generated at different power levels. To assess the reliability of the developed code system for back-end cycle analysis, validation study was performed with 58 measured samples of pressurized water reactor (PWR) SNF, and code-to-code comparison was conducted with STREAM-SNF, HELIOS-1.6 and SCALE 5.1. The V&V results presented that the developed code system can provide reasonable results with comparable confidence intervals. As a result, this paper successfully demonstrates that the isotope inventory prediction code system can be used for spent nuclear fuel analysis.

Segmental Analysis of Curved Non-Prismatic Prestressed Concrete Box Girder Bridges (시공단계를 고려환 곡선변단면 프리스트레스트 콘크리트 박스거더교량의 해석)

  • Park, Chan Min;Kang, Young Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.1
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    • pp.71-81
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    • 1994
  • A method is presented for the analysis of curved segmentally erected prestressed concrete box girder bridges including time-dependent effects due to load history, temperature history, creep, shrinkage, aging of concrete and relaxation of prestressing steel. The segments can be either precast or cast-in-place. Thin-walled beam theory and finite element method are combined to develop a curved nonprismatic thin-walled box beam element. The element consists of three nodes and each node has eight displacement degrees of freedom, including transverse distortion and longitudinal warping of the cross section.

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Ontological Analysis on the Phenomenon of Contemporary Architecture - Focused on the Avant-garde in the End of the 20th Century - (현대건축 현상의 존재론적 해석 - 20세기말 아방가르드를 중심으로 -)

  • Byun, Gye-Sung
    • Journal of architectural history
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    • v.14 no.2 s.42
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    • pp.21-40
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    • 2005
  • The purpose of this study was to analyze the features of the avant-garde architecture in the end of the 20th Century based on the ontology as a metalanguage. In view of the results so for achieved, it is possible to say that the thought of becoming, topology, rhizome thought and the Deleuze's concepts of the fold and the event as ever-changing and evolving at any given time are found in the avant-garde architecture, and the introduction of ontological thought into architectural design encourage hopes for a more natural and existential quality in architecture. However, the avant-garde architecture in the end of the 20th century disclosed the limitation in the architectural expression of ontological thought due to the lack of fully understand on ontology. In conclusion, the ontological approach in architecture offers a new morphological methodology and a new way of programming considering the existential aspect of space through the bricoleur's means leaving the ontological meaning of architecture itself.

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A Bibliographical Analysis on Bean sprouts (콩잎에 대한 문헌적 고찰)

  • Lee, Sun Ah;Park, Sang Young;Ahn, Sang Woo
    • The Journal of Korean Medical History
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    • v.21 no.1
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    • pp.109-115
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    • 2008
  • Bean sprouts have been one of the vital food for our ancestor for a long time. They were also hardy wild plants or first-aid medicine for needy people. Even nowadays they are served at table. For examples, bean curd, bean-curd dregs, bean sprouts, soybean paste, fermented soybeans, hot pepper paste, and soy are our daily food. Moreover bean sprouts are widely favored at the age of the well-being. Bean sprouts for a recover from a hangover, soybean paste for the prevention of cancer, beans leaf as the best well-being food for a diet, and so on. Thus the paper explains the origin of bean sprouts and their application as a food or medicinal stuff with the analysis of the various and wide-spread records.

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Dvnarnic Reswnse of Laminated Com~osite Shell under Low-Velocity Impact (복합적층쉘의 저속충격에 대한 동적 거동 해석)

  • 조종두;조영훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.969-974
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    • 1994
  • The dynamic behavior of graphite/epoxy laminated composite shell structure due to low-velocity impact is investigated using the finite element method. In this analysis, the Newmark's constant-acceleration time integration algorithm is used. The impact response such as contact force, central deflection and dynamic strain history form shell structure analysis are compared with those form the plate non-linear analysis. The effects of curvature, impact velocity and mass of impactor on the composite shell are discussed.

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