• Title/Summary/Keyword: Critical Theory

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A Study on the Design of Liquid Flow Control Valves for the Plants and Ships (플랜트 및 선박의 액체용 유량제어밸브 설계에 관한 연구(I))

  • 최순호;박천태
    • Journal of Advanced Marine Engineering and Technology
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    • v.19 no.1
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    • pp.28-35
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    • 1995
  • The fluid flow for a energy transfer is essential for the design and operation of power plants, petrochemical plants and ships including a process. When the operating conditions of a plant are changed or any transitional event occured, the flow controls of a fluid must be performed to follow the new operating state or mitigate the results of a event. Generally these flow controls to accommodate the new operating state of a plant are made by the use of various valves. The refore the design of valves and the related techniques are very important to the system and component designs. However the system and component design are not familiar with the practical theory of the valve since the derivative procedures of the flow equations in a valve are difficult and it is not easy to found the theoretical foundamentals and informations about the design of a valve from the present references. In this study the flow equations applicable to a valve for liquid are theoretically derived in detail. And the definition of valve reynolds number and its boundary values between the tubulent and laminar flow is described compared with the values of a circular pipe flow.

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Development of a Magnetic Seal and the Leak Test (마그네틱씰 개발 및 기밀 평가 시험)

  • Kim, Ock-Hyun;Lee, Min-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.2
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    • pp.79-83
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    • 2011
  • Magnetic seal uses a magnetic fluid to seal a gap between a rotating shaft and housing. It is distinguished from other kinds of seals from the fact that solid contact does not occur in the seal. This implies that it is free from solid rubbing thus dustless and provides a clean circumstance. That is the reason why the magnetic seal is used exclusively for most of vacuum chambers in semiconductor process where dustless clean circumstance is critical. A magnetic seal has been developed of which design parameters are determined based on published data, and an air pressure test has been done to examine its sealing capability. Effects of some design parameters have been studied through FEM analysis. The results show some notable aspects of design parameters and provide suggestions for developing the seals. Regarding the sealing capacity of the magnetic seal the factor to match the theoretical value with the actual one was found to be 0.4~0.7, which means still there is some discrepancy between theory and actual.

Evaluation of Oxidative Stress and Antioxidant Enzyme Expression in Human Hepatocarcinoma SK-Hep-1 Cells Treated with Stearic Acid (인간 간암 세포주인 SK-Hep-1에서 Stearic Acid에 의한 산화적 스트레스 및 항산화효소의 발현변화 평가)

  • Oh, Jung-Min;Lee, Ji-Yoon;Lee, Gwan-Ho;Kim, Bong-Hee;Kim, Sang-Kyum
    • YAKHAK HOEJI
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    • v.56 no.1
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    • pp.14-19
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    • 2012
  • Nonalcoholic steatohepatitis(NASH) is serious metabolic disease related to fatty acid. According to "two hit theory", fatty acid-induced oxidative stress is important factor to progress nonalcoholic steatohepatitis from steatosis. In this study, we evaluated stearic acid induced oxidative stress in human hepatocarcinoma SK-Hep-1 cell. Cell viability, reactive oxygen species (ROS) production, glutathione (GSH), malondialdehyde and expression of antioxidant enzymes were determined at various time-points and concentrations of stearic acid. At 0.2 mM, non-toxic concentration, of stearic acid, production of ROS was significantly increased at 24 hours and the level of GSH was significantly decreased. Expression of superoxide dismutase-1 and 2 was slightly increased in 0.2 mM stearic acid at 24 hours. These results represent that the non-toxic concentration of stearic acid resulted in oxidative stress, suggesting that stearic acid may play a critical role in development of steatohepatitis.

Development of structural integrity evaluation program for reactor vessel under pressurized thermal shock (가압열충격에 대한 원자로용기의 구조건전성 평가프로그램의 개발)

  • 정명조
    • Computational Structural Engineering
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    • v.9 no.2
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    • pp.153-161
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    • 1996
  • In this paper, theory of fracture mechanics for the pressurized thermal shock is investigated and numerical procedure for the evaluation of the pressure vessel under pressurized thermal shock is developed. For the given material properties, transient history such as temperature and pressure, and postulated flaw, the stress distribution is obtained to calculate stress intensities for a wide range of assumed crack sizes. The stress intensities are compared with the material fracture toughness values corresponding to the chemical compositions and the distribution of the nil ductility transition temperature, to determine the crack growth during the transient. Plant-specific calculations have been performed for several transients and the evaluation results are discussed.

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Understanding Postmodern Consumer Culture through Fashion Adveytisements: Deconstruction of Calvin Klein's Fashion Advertisements

  • Lee, Jaeil
    • The International Journal of Costume Culture
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    • v.5 no.3
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    • pp.173-183
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    • 2002
  • The main focus of this study is to understand realities of postmodern consumer culture by deconstructing fashion advertisements, Calvin Klein's ck One and cK be. The metaphysics of critical theory, visual and textual analysis are used to deconstructing the ads applying one of the postmodern cultural critics, Baudrillard' s notion of hyperreality. Through deconstructing the ads five postmodern characteristics representing hyperreality were found. First, there is no message regarding functional characteristics of the product offered in the ad, which is far from the modernist's utilitarian Point of view. Hyperreality in Postmodern consumer culture is consumption centered and focuses on the product's symbolic meanings. Second, especially for cK be, the ad uses atypicai, irrelevant models and images, which are introduced as a concept of ‘real people’ rather than the ideal person or body type. Third, there are transformations of the meanings from cK one to cK be such as the notions of globalization and gender which clearly represent ongoing reality in the Postmodern culture. Fourth, there are hidden meaning of hedonism and relativism, which are prevalent in postmodern ideology. Finally, models' bodies are used to convey messages as well as form the ground and figure in the ad that is a significant characteristic of postmodern consumer culture. In conclusion, the study of Calvin Klein's fashion ads supports the notion that advertising mirrors reality in postmodern consumer culture, which is hyperreality.

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Analysis of Split Magnetic Fluid Plane Sealing Performance

  • Zhang, Hui-tao;Li, De-cai
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.133-140
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    • 2017
  • Split magnetic fluid sealing is a combination of magnetic fluid rotary and plane sealing. Using the theory of equivalent magnetic circuit design as basis, the author theorized the pressure resistance performance of magnetic fluid plane sealing. To determine the pressure resistance of magnetic fluid plane sealing, the author adopted the method of finite element analysis to calculate the magnetic field intensity in the gap between plane sealing structures. The author also analyzed the effect of different sealing gaps, as well as different ratios between the sealing gap and tooth and solt width, on the sealing performance of split magnetic fluid. Results showed that the wider the sealing gap, the lower the sealing performance. Tooth width strongly affects sealing performance; the sealing performance is best when the ratio between tooth width and sealing gap is 2, whereas the sealing performance is poor when the ratio is over 8. The sealing performance is best when the ratio between the solt width and sealing gap is 4, indicating a slight effect on sealing performance when the ratio between the solt width and sealing gap is higher. Theoretical analysis and simulation results provide reference for the performance evaluation of different sealing equipment and estimation of critical pressure at interface failure.

A Study on Surrealistic Expression in Modern Fashion - Focusing on Surrealistic Fashion in 1990s -

  • Yang, Chieu-Kyung
    • Journal of Fashion Business
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    • v.8 no.6
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    • pp.39-56
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    • 2004
  • At the outset, surrealism starts from pure art, but surrealism has greatly influenced commercial art and fashion circles, more so than any other genre of art. The critical thinking methods of surrealism and its mode of expression continues to influence fashion theory extensively. Even now, surrealism may be found in the designs presented in fashion circles and is still expected for future lines. Surrealism in modern fashion has been reborn, newly integrated and transformed, based on the features of Surrealism paintings. The characteristics of its forms can be found in a combination of modern material, modern design and new skills and the classical items : bodyform molding context of architecture, experimental and sex-appealing of body. Expression was made by borrowing natural motives and recreating natural fabrics while the existing typical idea about clothes was destructed, with the boundary of patterns changed. Expression was also made by mixing items, uniting future images, and using up-to-date functional techniques. This study is significant that up-to-date technological culture expands cyber-space and increases surrealistic expressions by combined heterogeneous materials, thus arousing much interest. The purpose of this study is to determine interrelationship between how surrealism developed and what formative properties those clothes affected by surrealism obtained in the 1990s.

Issues and Persyectivbes for Research on Living Environment of ‘The Third Age’ -focusing on Social constructionism approach- (제3의 연령기의 공간환경연구를 위한 관점과 쟁점 -사회구성주의적 접근을 중심으로-)

  • Hong, Hyung-Ock
    • Journal of Families and Better Life
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    • v.20 no.6
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    • pp.37-48
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    • 2002
  • Mid of 1980s witnessed the beginning of a new trend regarding the elderly as the Third Age Group, which is capable of positive selection for their later life. These changes are caused not only by the rising cost of caring them as the dependent to the society, but also by paradigm shift from the clinical and biomedical model to political economy and critical gerontology. The paradigm shift is based on the social constructionism as a perspective on the later life. In this communication the development of social constructionism is reviewed as an approach on the living environment for later life through literature survey. Emphases were made on the anti-ageism instead of ageism in the analysis of the social constructionism perspective for living environment in later life. Individual practice, influencing the practice of others, influencing agency policy, and developing theory were addressed and emphasized for the practice of anti-ageism. This study found the importance of the development of the social constructionism perspective on the study and practice regarding living environment for ‘the Third Age’ in Korean situation.

A Study on the perspectives on Curriculum of Middle School Home Economics Teachers and Technology Teachers by Socio-demographic Variables (중학교 가정과 교수와 기술화 교사 및 사회 인구학적 변인에 따른 교육과정 관점에 관한 연구)

  • 박명주;유태명
    • Journal of the Korean Home Economics Association
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    • v.39 no.11
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    • pp.161-174
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    • 2001
  • In the 7th curriculum revision, Home Economics and Technology are combined into one subject, Practical Arts(Technology Home Economic), from 5th to 10th grades. The purpose of this study was to ewamine what perspectives home economics teachers and technology teachers have on curriculum. A questionnaire survey was carried out to the 297 middle school home economics teachers and technology teachers across the nation, to find out the differences of their perspectives on curriculum by independent variables. The findings of this study were as follows: 1) Both groups of home economics teachers and technology teachers supported interpretive, emancipators, and technical perspective on curriculum in the order named. 2) Teachers who have teaching experience of 21 years or more showed higher orientation toward technical perspective than those who have teaching experience of 10 years or less in assumptions on society, educational goal, Knowledge, and teaching-loaming method. 3) Public school teachers showed stronger orientation toward technical perspective in assumptions on teaching-learning method, and toward emancipatory perspective in assumptions on society. 4) Teachers who majored in or took charge of Technology generally had strong orientation toward technical perspective, whereas those who majored in or took charge of Home Economics oriented more toward interpretive or emancipatory than technical perspective.

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A Study on Architectural Polychromy applied to the 19th century Church Architecture in France (19세기 프랑스 성당 건축의 다색채 장식에 관한 연구)

  • Kang, Sang-Hoon
    • Korean Institute of Interior Design Journal
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    • v.16 no.4
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    • pp.99-109
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    • 2007
  • In the 19th century, a series of study by Hittorff, Semper, Ruskin, and others on architectural polychromy in various perspectives appeared. This presumed that the architectural polychromy could become an essential part of architectural composition and contribute to create new architectural style, if not, at least new architectural and cultural context of the 19th century, the period when it is considered that the stylistic evolution in architecture is absent. In the course of the stylistic development of church architecture of the 19th century in France, the architectural polychromy, grounded in a theory of representation, played a critical role as one of the main sources to create new architectural vision. The church architecture during the Second Empire in France was particularly susceptible to be influenced by this inevitable phenomenon, which signified an epistemological mutation in architectural perception beyond optical and perspective effect in the history of architecture. Here the study attempts to recognize the aesthetic value of the architectural polychromy in the 19th century, and investigate its application, as not just an aspect of architectural embellishment but an indispensable portion of architectural vocabulary, on the church architecture in France throughout the 19th century, then to define its role in creating new architectural environment.