• Proceedings of the KSME Conference
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• 2002.08a
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• pp.131-134
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• 2002

Compressible gas flow through a convergent-divergent nozzle is choked at the nozzle throat under a certain critical pressure ratio, and then being no longer dependent on the pressure change in the downstream flow field. In practical, the flow field at the divergent part of the critical nozzle can affect the effective critical pressure ratio. In order to investigate details of flow field through a critical nozzle, the present study solves the axisymmetric, compressible, Wavier-Stokes equations. The diameter of the nozzle throat is D=8.26mm and the half angle of the diffuser is changed between $2^{\circ}\;and\;10^{\circ}$ Computational results are compared with the previous experimental ones. The results obtained show that the divergence angle is significantly influences the critical pressure ratio and the present computations predict the experimented discharge coefficient and critical pressure ratio with a good accuracy. It is also found that a nozzle with the half angle of $4^{\circ}$ nearly predicts the theoretical critical pressure ratio.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.73-88
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• 2014

Various studies on the critical flow models for sub-cooled and/or saturated water were reviewed, especially on Fauske, Moody, and Henry for basic theoretical models; Zaloudek for insight into physical phenomena for a critical flow in an orifice type flow path; Sozzi & Sutherland for a critical flow test of saturated and sub-cooled water at high pressure for orifice and nozzles; and a Marviken test on a full-scale critical flow test. In addition, critical flow tests of sub-cooled water for the break simulators in integral effect test (IET) facilities were also investigated, and a hybrid concept using Moody's and Fauske's models was considered by the authors. In the comparison of the models for the selected test data, discussions of the effect of the diameters, predictions of the critical flow models, and design aspects of break simulator for SBLOCA scenarios in the IET facilities were presented. In the effect of diameter on the critical flow rate with respect to all dimensional scales, it was concluded that the effect of diameter was found irrespective of diameter sizes. In addition, the diameter effect on slip ratio affecting the critical flow rate was suggested. From a comparison of the critical flow models and selected test data, the Henry-Fauske model of the MARS-KS code was found to be the best model predicting the critical flow rate for the selected test data under study.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.1
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• pp.46-56
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• 2012

Purpose: The purpose of this study was to identify the relationships among professional self-concept, critical thinking disposition and clinical competence in nursing students. Method: The participants in the study were 505 nursing students, 262 associate degree nursing students and 243 baccalaureate nursing students, all in schools in Gwangju or South Jeonla Province. A questionnaire survey was conducted from April 25 to May 27, 2011. Statistical processing was performed with SPSS 18.0 Version and the data were analyzed using t-test, ANOVA, Scheff$\acute{e}$ test, Pearson correlation coefficients, and multiple stepwise regression. Results: There was a positive correlation among clinical competence and professional self-concept, critical thinking disposition. The most effective factor for clinical competence was professional practice in professional self-concept, followed by prudence and objectivity in critical thinking disposition. The total explanation of clinical competence was 46.2%. Conclusion: The results of this study indicate confirm that professional self-concept and critical thinking disposition have an effect on clinical competence in nursing students. Accordingly in order to improve clinical competence, it is necessary to provide practice environment and educational curriculum that enhance the professional self-concept and critical thinking disposition of nursing students.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.567-572
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• 2008

This paper's purpose is to improve determining of the critical response of curved bridge to multi-component seismic motion. There are several methods to combine responses by multi-component excitation response, 30%, 40% rules and square-root-of-sum (SRSS). These combination rules determine same value of critical response in straight bridges. However, each method has critical response value of different magnitude in curved bridges. Thus a study about critical response of curved bridges is required. This paper presents comparison critical responses value as each combination rule, 30%, 40% rules and SRSS on curved bridges with the different radiuses of curvature. This study was carried out by response spectrum analysis of OO IC steel box girder bridge using SAP2000. It is concluded as follows: 1) In curved bridges, 30% and 40% rules tend to underestimate the critical response relatively to SRSS. 2) When bridges have smaller radiuses than 100m, difference between SRSS and 30% or 40% rules let run errors up as radiuses of curvature decreased.

• Geomechanics and Engineering
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• v.15 no.6
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• pp.1193-1205
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• 2018

A footing located on slopes possess relatively lower bearing capacity as compared to the footing located on the level ground. The bearing capacity further reduces under seismic loading. The adverse effect of slope inclination and seismic loading on bearing capacity can be minimized by proving sufficient setback distance. Though few earlier studies considered setback distance in their analysis, the range of considered setback distance was very narrow. No study has explored the critical setback distance. An attempt has been made in the present study to comprehensively investigate the effect of setback distance on footing under seismic loading conditions. The pseudo-static method has been incorporated to study the influence of seismic loading. The rate of decrease in seismic bearing capacity with slope inclination become more evident with the increase in embedment depth of footing and angle of shearing resistance of soil. The increase in bearing capacity with setback distance relative to level ground reduces with slope inclination, soil density, embedment depth of footing and seismic acceleration. The critical value of setback distance is found to increase with slope inclination, embedment depth of footing and density of soil. The critical setback distance in seismic case is found to be more than those observed in the static case. The failure mechanisms of footing under seismic loading is presented in detail. The statistical analysis was also performed to develop three equations to predict the critical setback distance, seismic bearing capacity factor ($N_{{\gamma}qs}$) and change in seismic bearing capacity (BCR) with slope geometry, footing depth and seismic loading.

• Journal of Korean Critical Care Nursing
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• v.4 no.2
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• pp.1-14
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• 2011

Purpose: This study was aimed to understand and describe the Korean critical care advanced practice nurses' work experience. Methods: Data was collected through 2 focus group interviews that were held in two different university hospitals in Seoul, Korea. All interviews were recorded and transcribed, and data were analysed using modified qualitative content analysis. Results: Ten themes were drawn from data analysis. They are "Various and complex tasks", "Excellency of advanced nursing practice", "Pressure and responsibility accompanied with pride", "Role identity confusion", "Role conflict", "Leaping and evolving role", "Gap between role and outcome evaluation", "Underestimated outcomes", "Where are my outcomes?" "Searching for outcomes: publicize the role". Conclusion: The results of this study help to understand the role of Korean critical care advanced practice nurses and to guide to outcome evaluation of their role effectiveness. Developing qualitative outcome indicators, cost-effectiveness ananlysis of Korean critical care advanced practice nurses' role, and accumulation of evidences through researches on outcome evaluation will be needed to successfully settle down advanced practice nursing in Korea.

• The Journal of the Korea Contents Association
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• v.20 no.9
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• pp.681-689
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• 2020

The purpose of this study is to identify learning attitudes, problem-solving skills, critical thinking tendencies, and the effects on learning attitudes for dental hygienist. It was. The data analysis method analyzed the general characteristics of the subjects, and the learning attitude, critical thinking disposition, and problem solving ability were examined with the mean, standard deviation, and correlation between each variable. t-test, ANOVA, and hierarchical regression analysis were used for the study attitude, critical thinking tendency, and problem solving ability according to the general characteristics of the study subjects. As a result of this study, grades were the most influential variables, and self-confidence and skepticism influenced learning attitudes as a sub-factor of critical thinking. In this study, the first grade of dental hygiene and enrolled students was the highest. Development of programs to effectively raise critical thinking tendency and problem solving ability for first graders, and research on characteristics of learners, major satisfaction, adaptation to college life, problem-based learning and preceptorship should be continuously conducted. It is feed.

• Quality Improvement in Health Care
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• v.7 no.2
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• pp.156-167
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• 2000

Background: Emphasis in healthcare during the 1990s has been to provide both optimal wellness and function with quality in a Cost-effective manner. Critical pathway was developed to meet the need to guide clients along the continunm of care and to achieve continuity of care. The purpose of this study is to review and analyze articles related to the critical pathway that had developed and applied in Korea and abroad from 1995 to 1999. Methods: Total 39 studies were analyzed in terms of group of application, need of development, horizontal axis: time frame, vertical axis : items of care, task force team, identification of preliminary critical pathway, validation of preliminary critical pathway, types of final critical pathway, a person who coordinates and effects on critical pathway. Results: In the aspect of group of application, there were various diseases in the overseas than in Korea. In domestic and overseas, the horizontal axis included mainly the time from the start of hospitalization to discharge and vertical axis of the critical pathway included commonly the following nine items : tests, diet, medications, consultations, activity, assessments, treatments, education, discharge planning. Preliminary critical pathway was mainly drawn up through chart review in both. Types of final critical pathway were mostly for medical team use in Korea and were for medical team and patient use in abroad. A person who coordinates critical pathway was mostly nurse in abroad. There was positive effects on critical pathway in both. Conclusion: Staff education and information about critical pathway are needed to use it effectively.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3003-3008
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• 2007

Critical nozzle has been frequently employed to measure the flow rate of various gases, but hydrogen gas, especially being at high-pressure condition, was not nearly dealt with the critical nozzle due to treatment danger. According to a few experimental data obtained recently, it was reported that the discharge coefficient of hydrogen gas through the critical nozzle exceeds unity in a specific range of Reynolds number. No detailed explanation on such an unreasonable value was made, but it was vaguely inferred as real gas effects. For the purpose of practical use of high-pressure hydrogen gas, systematic research is required to clarify the critical nozzle flow of high-pressure hydrogen gas. In the present study, a computational fluid dynamics(CFD) method has been applied to predict the critical nozzle flow of high-pressure hydrogen gas. Redlich-Kwong equation of state that take account for the forces and volume of molecules of hydrogen gas were incorporated into the axisymmetric, compressible Navier-Stokes equations. A fully implicit finite volume scheme was used to numerically solve the governing equations. The computational results were validated with some experimental data available. The results show that the coefficient of discharge coefficient is mainly influenced by the compressibility factor and the specific heat ratio, which appear more remarkable as the inlet total pressure of hydrogen gas increases.

• The Korean Journal of Health Service Management
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• v.9 no.1
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• pp.67-79
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• 2015

The aim of this descriptive cross-sectional study was determine the effect of critical thinking and clinical decision-making on ethical dilemmas. A survey of dental hygienists residing in Busan and South Gyeongsang, Korea was conducted using convenience sampling between September and December, 2013. A total of 153 responses were used in the final analysis. Data analysis and structural equation modeling were performed with IBM SPSS Statistics(version 21.0) and AMOS(version 18.0) programs. A negative(-) correlation coefficient(-0.37) was observed between critical thinking and ethical dilemmas on statistical analysis, i.e., higher critical thinking led to less ethical dilemmas(p=0.024, CR=-2.264). The values from the structural equation model were ${\chi}^2=98.124$ df=66, GFI=0.919, AGFI=0.871, and RMSEA=0.057. This study proposed a theoretical model in which critical thinking, ethical values, and decision-making skills should be firmly established to effectively respond to specific situations, such as ethical dilemmas, and that greater tendencies for critical thinking led to less ethical dilemmas, thereby demonstrating a negative(-) correlation between the two parameters.