• 제목/요약/키워드: critical means

검색결과 972건 처리시간 0.025초

위핑 유동 조건에서의 직사각형 체 주위 유동의 수력학적 분석 (Hydrodynamic Analysis of Rectangular Sieve Tray under Weeping Conditions)

  • 호산나 우위톤즈;이인원
    • 한국가시화정보학회지
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    • 제15권3호
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    • pp.34-40
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    • 2017
  • Within fractionating devices existing in separation and purification industries, sieve trays are widely used as tower internals and their choice is due to economical attractiveness. While operating a trayed distillation tower weeping phenomenon has a critical effect on the efficiency, in this case study a weeping phenomenon was undertaken by means of numerical model in a rectangular sieve tray. Eulerian-Eulerian Computational Fluid Dynamics (CFD) method was used and the obtained CFD results are in a good agreement with the experimental data in terms of weeping rate and pressure drop.

A novel hybrid testing approach for piping systems of industrial plants

  • Bursi, Oreste S.;Abbiati, Giuseppe;Reza, Md S.
    • Smart Structures and Systems
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    • 제14권6호
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    • pp.1005-1030
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    • 2014
  • The need for assessing dynamic response of typical industrial piping systems subjected to seismic loading motivated the authors to apply model reduction techniques to experimental dynamic substructuring. Initially, a better insight into the dynamic response of the emulated system was provided by means of the principal component analysis. The clear understanding of reduction basis requirements paved the way for the implementation of a number of model reduction techniques aimed at extending the applicability range of the hybrid testing technique beyond its traditional scope. Therefore, several hybrid simulations were performed on a typical full-scale industrial piping system endowed with a number of critical components, like elbows, Tee joints and bolted flange joints, ranging from operational to collapse limit states. Then, the favourable performance of the L-Stable Real-Time compatible time integrator and an effective delay compensation method were also checked throughout the testing campaign. Finally, several aspects of the piping performance were commented and conclusions drawn.

SNS에서 대인신뢰의 영향요인 : 트위터 사용자 경우 (Antecedents of Interpersonal Trust in SNS : In Case of Twitter Users)

  • 우관란;송희석
    • Journal of Information Technology Applications and Management
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    • 제19권2호
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    • pp.197-215
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    • 2012
  • SNS has been recognized as a means of expanding social capital by promoting interaction and efficient communication among users. On the other hand, there are serious concerns on negative side of social network which is often called epidemics. Trust plays a critical role in controlling the spread of distorted information and vicious rumor as well as reducing uncertainties and risk from unreliable users in social network. This study focuses on what the antecedents of interpersonal trust are in social network. We performed online survey from 252 Twitter users and tested candidate antecedents which are chosen from previous literature. As a result, propensity to trust of trustor, ability and sincerity of trustee, intimacy between trustor and trustee significantly affected to the interpersonal trust in Twitter.

변화관리요인이 중소기업의 ERP도입성과에 미치는 영향 연구 (A Study on the Effect of Change Management for the ERP Performance in Small and Medium Companies)

  • 박치관
    • Journal of Information Technology Applications and Management
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    • 제15권4호
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    • pp.123-136
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    • 2008
  • This study tried to find out the effect of change management on the ERP performance in small and medium size companies. Communication, BPR management, education and training were selected as independent variables which might bring an effect on ERP performances which were classified as quality and quantity one. Structure equation model was built and analyzed with AMOS 5.0 version from data gathered through 127 companies which already implemented ERP systems. The result of this study shows that all the three independent variables give positive impacts on two dependent variables, which means change management is critical when small and medium size companies want to implement ERP systems.

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초미세 발포 사출 성형품의 단열 특성 (The Insulation Property of Microcellular Injection Molding Plastics)

  • 이정현;홍순국;김지현;윤재동
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집C
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    • pp.263-268
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    • 2001
  • MCPs means Micro Cellular Plastics. The micro-cells are generated in the products by the difference of dissolution through the pressure drop after super critical fluid of CO2 or N2 dissolves into polymer. We have developed injection molding process adopting MCPs and applied it to a broad range of injection molded thermoplastic materials and applications. It can prevent the leakage of impact strength and increase the thermal conductivity, moreover regulate the thermal conductivity. Then we can develop the high strength foaming plastics. Also, it can be gained a competitive advantage by utilizing its processing benefits, e.g. the lightweight products and significant reductions in material consumption.

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견의 정련 방법에 관한 연구(1) - 패키지 정련 - (A Study on the Silk Degumming(1) - Degumming of Silk on Package -)

  • 김문식;김용학
    • 한국염색가공학회지
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    • 제18권3호
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    • pp.16-22
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    • 2006
  • Process contract has received considerable attention in silk degumming processes because of its critical role in quality assurance. In degumming, process exhibits shrinkage of high twisted yarn and lot-varying behavior, thus increasing the difficulties of reduction by conventional means. This necessitates the application of a package that adapts to changing degumming process, and a new approach involving package degumming is proposed. The gains of this process are prevent of shrinkage by package winding, which is simplified by reduced soft-winding or re-twisting process. The approach is expected to achieve high quality results in conventional process due to its feature of demage by tension and rubbing. Therefore package degumming has many merits such as reduce of pilling and shrinkage, production expenses saving by process contract are expected of the simplified degumming process.

Strategic Analysis Evolution: Scenario Planning and Simulation Based on The Methodology of System Dynamics

  • Bassi, Andrea M
    • 한국시스템다이내믹스연구
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    • 제5권2호
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    • pp.199-216
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    • 2004
  • The present study is aimed at developing the optimal instruments for dispelling the uncertainty factors during the formulation of strategies for corporate development. The objective is the creation of a complete model of strategic analysis, which encompasses both the environment (internal and external) and the management rational component. This model -built on the analysis of three corporate cases - is concretized by a simulation for testing the strategy by the means of software which enables the users to cope with a dynamic and complex corporate environment. The research questions regard the development of a complete strategic analysis, which covers the entire decision-making process; the concrete assessment of the business strategy on the basis of quantitative data: the identification and enhancement of the critical variables of business administration, in such a complex and dynamic reality as the corporate environment.

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유리 피판술을 이용한 손의 연부 조직 재건술 (Free Flaps for Hand Soft Tissue Reconstruction)

  • 김용진;함동길
    • Archives of Reconstructive Microsurgery
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    • 제21권1호
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    • pp.76-80
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    • 2012
  • Various soft tissue defects can be occurred in the hand. In determining the most suitable means of reconstruction a defect, the benefit of the reconstruction has to outweigh the risk of donor morbidity. Flap selection will be based on the size of the defect, the requirements for sensibility, the surgeon's comfort level, and the patient profile such as gender, age, or systemic disease. The hand is the most important tactile sensory organ, hence sensory restoration is critical. Neurosensory free flaps can provide sensibility, vascularity, and soft tissue coverage to an injured hand. This paper will discuss free flaps which can be used for soft tissue reconstruction of the hand.

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품질비용 발생편차와 품질관리활동 그리고 성과간의 관계:품질성과와 납기성과를 중심으로 (The Relationships among the Degree of Quality Cost Deviation, Quality Management Activities and Performance)

  • 김달곤;김순기;정순여
    • 품질경영학회지
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    • 제31권4호
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    • pp.1-18
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    • 2003
  • Quality is a critical competitive factor in today's environment because of the impact of quality on costs and delivery. Many companies regard quality as a key concept of company strategy in order to achieve the competitive edge. Measuring and reporting quality cost is the first step in quality management program. The supposition of quality cost model is that investment in prevention activities will bring rewards from reduced failure costs, and that further investment in prevention activities will show profits from reduced appraisal costs. In this study, the degree of quality cost deviation is conceptualized. This means a deviation between the ideal and present ranking in the amounts of quality cost categories. This study analysed that the effect of its deviation on quality management activity and performance variables. However, there are no difference in these variables. The major reason is that most of companies are endeavoring for quality management but operating quality cost system unsystematically. The review against a prevention and appraisal activity is necessary.

An Investigation of Thermal Margin for External Reactor Vessel Cooling(ERVC) in Large Advanced Light Water Reactors(ALWR)

  • Park, Jong-Woon;Jerng, Dong-Wook
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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    • pp.473-478
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    • 1997
  • A severe accident management strategy, in-vessel retention corium through external reactor vessel cooling(ERVC) is being studied worldwide as a means to prevent reactor vessel failure following a core melt accident. An evaluation of feasibility of this ERVC for a large Advanced Light Water Reactor (ALWR) is presented. To account for the coolability of corium and metal in the reactor vessel, a thermal analysis is performed using an existing method. Results show that the peak heat flux along the inner surface of the reactor vessel lower head has a relatively smaller margin than a small capacity reactor such as AP600 in regards with the critical heat flux attainable at the outer surface of the reactor vessel lower head.

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