• Title/Summary/Keyword: Critical state

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The Effects of Extended Family Visiting Hours in the Intensive Care Unit (중환자실 가족면회 시간 연장의 효과)

  • Lee, Young-Ock;Kang, Ji-Yeon
    • Journal of Korean Critical Care Nursing
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    • v.4 no.1
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    • pp.51-63
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    • 2011
  • Purpose: This study aimed to examine the effects of extended family visiting hours in the intensive care unit (ICU). Methods: The subjects were 168 ICU patients and their family members. Two 30-minute visits a day were allowed to the control group according to current policy, while four 30-minute visits a day were allowed to the experimental group. Patients' state anxiety was measured at the first day of ICU admission, and on the third day of ICU admission patients' anxiety and family satisfaction were measured. For the infection rate, comparison was made between the experimental and control data-collecting periods. Results: The patients' state anxiety significantly decreased in the experimental group. Family satisfaction of experimental group was significantly higher than that of control group. There was no significant difference in the infection rate. Nurses positively evaluated extension of visiting hours because it could stabilize patients, reduce the number of arrangements for additional visits, and help establish trust relationship with families. Conclusion: Extended family visiting hours in the ICU reduced patients' anxiety and improved family satisfaction but had no effect on the infection rate. Extended family visiting hours in the ICU is expected to improve the quality of critical care.

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A Systematic Review Exploring the Current State of Fashion Criticism -A Focus on the Fashion Designer Exhibition Reviews of Fashion Theory-

  • Choi, Kyung-Hee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.44 no.2
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    • pp.273-294
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    • 2020
  • Considering the complex relationship between fashion curating and the critical approach of fashion exhibition reviews, this study explores the current state of fashion criticism in museology, focusing on fashion designer exhibition reviews of Fashion Theory. The author selected eighteen exhibition reviews of individual fashion designers' works from 1997 on to the current 2020 issues of Fashion Theory, which provides an interdisciplinary forum to analyze fashion as a cultural construction. The author performed a systematic review that qualitatively summarizes and/or synthesizes the findings of the studies on the topic with the process of a systematic review, such as key question formulation, analytic framework building, evidence mapping, critical appraisal, and evidence synthesis. The results of this study are as follows. First, the exhibition reviews included almost all stages of the inclusive fashion criticism model, based on an artifact study. Second, they reflected various critical discourses that offered current interpretations of historical and contemporary fashion. Third, they showed that fashion criticism in the museum context is the result of an interdisciplinary collaboration of various fashion agents. Finally, they offered a bridge for crossing the boundaries of various scholarly fields, as they combine multidisciplinary scholarship with object-based methods.

Effect of rain on flutter derivatives of bridge decks

  • Gu, Ming;Xu, Shu-Zhuang
    • Wind and Structures
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    • v.11 no.3
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    • pp.209-220
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    • 2008
  • Flutter derivatives provide the basis of predicting the critical wind speed in flutter and buffeting analysis of long-span cable-supported bridges. Many studies have been performed on the methods and applications of identification of flutter derivatives of bridge decks under wind action. In fact, strong wind, especially typhoon, is always accompanied by heavy rain. Then, what is the effect of rain on flutter derivatives and flutter critical wind speed of bridges? Unfortunately, there have been no studies on this subject. This paper makes an initial study on this problem. Covariance-driven Stochastic Subspace Identification (SSI in short) which is capable of estimating the flutter derivatives of bridge decks from their steady random responses is presented first. An experimental set-up is specially designed and manufactured to produce the conditions of rain and wind. Wind tunnel tests of a quasi-streamlined thin plate model are conducted under conditions of only wind action and simultaneous wind-rain action, respectively. The flutter derivatives are then extracted by the SSI method, and comparisons are made between the flutter derivatives under the two different conditions. The comparison results tentatively indicate that rain has non-trivial effects on flutter derivatives, especially on and $H_2$ and $A_2$thus the flutter critical wind speeds of bridges.

3D Dynamics of the Oscillating-Moving Load Acting in the Interior of the Hollow Cylinder Surrounded with Elastic Medium

  • Akbarov, Surkay D.;Mehdiyev, Mahir A.
    • Structural Engineering and Mechanics
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    • v.71 no.6
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    • pp.713-738
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    • 2019
  • In the paper the dynamics of the oscillating moving load acting in the interior of the hollow cylinder surrounded with elastic medium is studied within the scope of the exact field equations of 3D elastodynamics. It is assumed that the oscillating load act on the certain arc of the internal circle of the cylinder's cross section and this load moves with constant velocity along the cylinder's axis. The corresponding 3D dynamic problem is solved by employing moving coordinate system, the exponential Fourier transform and the presentation these transforms with the Fourier series. The expressions of the transforms are determined analytically, however their originals are found numerically. Under the investigations carried out in the paper the main attention is focused on the so-called "gyroscopic effect", according to which, the influence of the vibration frequency on the values of the critical velocity and interface stresses are determined. Numerical results illustrated this effect are presented and discussed. In particular, it is established how the non-axisymmetricity of the problem acts on the influence of the load oscillation on its critical velocity and on the interface stresses.

Program development and preliminary CHF characteristics analysis for natural circulation loop under moving condition

  • Gui, Minyang;Tian, Wenxi;Wu, Di;Chen, Ronghua;Su, G.H.;Qiu, Suizheng
    • Nuclear Engineering and Technology
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    • v.53 no.2
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    • pp.446-454
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    • 2021
  • Critical heat flux (CHF) has traditionally been evaluated using look-up tables or empirical correlations for nuclear power plants. However, under complex moving condition, it is necessary to reconsider the CHF characteristics since the conventional CHF prediction methods would no longer be applicable. In this paper, the additional forces caused by motions have been added to the annular film dryout (AFD) mechanistic model to investigate the effect of moving condition on CHF. Moreover, a theoretical model of the natural circulation loop with additional forces is established to reflect the natural circulation characteristics of the loop system. By coupling the system loop with the AFD mechanistic model, a CHF prediction program called NACOM for natural circulation loop under moving condition is developed. The effects of three operating conditions, namely stationary, inclination and rolling, on the CHF of the loop are then analyzed. It can be clearly seen that the moving condition has an adverse effect on the CHF in the natural circulation system. For the calculation parameters in this paper, the CHF can be reduced by 25% compared with the static value, which indicates that it is important to consider the effects of moving condition to retain adequate safety margin in subsequent thermal-hydraulic designs.

An Equation of State for the PVT Behavior of Gaseous Refrigerants (기체냉매의 PVT 거동을 나타내기 위한 상태방정식)

  • Park, K.;Sonntag, R.E.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.1
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    • pp.98-111
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    • 1995
  • The objective of this work is to investigate the form of equations of state for specific refrigerants. In particular, equations of the extended van der Waals form have been studied. As a result, a new equation of state has been developed and tested over ranges of pressure and density up to 5 and 1.5 times critical, respectively. The equation of state separates the compressibility factor into two parts. One is the repulsive compressibility factor and the other is attractive. The former is in the same form of Carnahan-Starling's repulsive term with constant hard-sphere volume. The latter is based on a combination of two different functions linear to density. The equation of state developed here has 12 adjustable parameters and correlates PVT data successfully. All properties are in reduced forms.

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A State-of-the-Art of Probabilistic Seismic Fragility Analysis of Critical Structure (핵심 구조물의 확률론적 지진취약도 분석: 기술현황)

  • 조양희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.04a
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    • pp.226-232
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    • 2000
  • Seismic probabilistic risk assessment(RA) rather than deterministic assessment provides more valuable information and insight for resolving seismic safety issues in nuclear power plant design. In the course of seismic PRA seismic fragility analysis is the most significant and essential phase especially for structural or mechanical engineers. Lately the seismic fragility analysis is taken as a useful tool in general structural engineering as well. A systemized and synthesized procedure or technology related to seismic fragility analysis of critical industrial facilities reflecting the unique experiences and database in Korea is urgently required. This paper gives a state-of-the-art reviews of PRA and briefly summarizes the technologies related to PRA and seismic fragility analysis before developing an unique technology considering characteristics of Korean database. Some key items to be resolved theoretically or technically are extracted and presented for the future research.

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Design and Implementation of an Ontology-based Context-Aware Platform for Home Healthcare (홈 헬스케어를 위한 온톨로지 기반 상황인지 플랫폼의 설계 및 구현)

  • Jo, Jung Won;Cha, Si Ho;Ahn, Byung Ho;Cho, Kuk Hyun
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.5 no.3
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    • pp.77-86
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    • 2009
  • This paper proposes an ontology-based context-aware home healthcare platform employing environmental factors obtained from home. The proposed platform manages the health of home residents, and notifies relatives or a medical team of critical condition through context-awareness based on home ontology by using information sensed from various sensors. The ontology definition of context-awareness from the sensed information provides technically more precise decision for us. Therefore the platform can be aware of the health state of residents and environment by reasoning exactly from data gathered from various sensors and heterogeneous devices. The platform also can individually provide the customized service for users by setting priority for critical status that can be occurred in the health state of residents.

Ionization and Attachment Coefficients in Mixtures of $SF_6$ and $N_2$ ($SF_6-N_2$ 혼합기체(混合氣體)의 전리(電離) 및 부착계수(附着係數))

  • Kim, Sang-Nam
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.1
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    • pp.44-47
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    • 2009
  • This paper describes the information for quantitative simulation of weakly ionized plasma. We must grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. $SF_6$ gas is widely used in industrial of insulation field. In this paper, $N_2$ is mixed to improve pure $SF_6$ gas characteristics. Electron transport coefficients in $SF_6-N_2$ mixture gases are simulated in range of E/N values from 70 to 400 [Td] at 300K and 1 Torr by using Boltzmann equation method. The results of this method. which are ionization coefficient, attachment coefficient, effective ionization coefficient, and critical E/N, can be important data to present characteristic of gas for insulation. Specially critical E/N is a data to evaluate insulation strength of a gas and is presented in this paper for various mixture ratios of $SF_6-N_2$ mixture gases.

Transition mechanism during the critical heat flux condition in flow and pool boiling (유동 및 풀비등에 있어서 한계열플럭스 상태하의 천이기구)

  • 김경근;김명환;권형정;김종헌;최순호
    • Journal of Advanced Marine Engineering and Technology
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    • v.13 no.4
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    • pp.40-53
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    • 1989
  • Boiling heat transfer phenomena is widely applied to BWR and electrical heating system because of its high heat transfer coefficient. In these systems, steady state heat transfer is dependent on nucleate boiling. When the heat generating rate is sharply increased or the cooling capacity of coolant is sharply decreased, sharp wall temperature rise is occurred under the critical heat flux(CHF) condition. This paper presents the simple wall temperature fluctuation model of transition mechanism in the repeating process of overheating and quenching, when coalescent bubble passes relatively slowly on the wall and simultaneously the transition from nucleate boiling to film boiling is carried at especially onset of the CHF state. The values calculated by the present model are resulted comparatively good with the measured.

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