• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1133-1138
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• 2003

The pressure tubes, which contain high temperature heavy water and fuel, are within the core of a CANDU nuclear reactor, and are thus subjected to high stresses, temperature gradient, and neutron flux. Further, it is well known that pressure tubes of cold-worked Zr-2.5Nb materials result in hydrogen diffusion, which create fully-hydrided regions (frequently called Blister). Thus a proper investigation of hydrogen diffusion within zirconium-alloy nuclear components, such as CANDU pressure tube and fuel channels is essential to predict the structural integrity of these components. In this respect, this paper presents numerical investigation of hydrogen diffusion to quantify the hydrogen concentration for blister growth of CANDU pressure tube. For this purpose, coupled temperature-hydrogen diffusion analyses are performed by means of two-dimensional finite element analysis. Comparison of predicted temperature field and blister with published test data shows good agreement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.189-195
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• 2004

The pressure tubes, which contain high temperature heavy water and fuel, are within the core of a CANDU nuclear reactor, and are thus subjected to high stresses, temperature gradient, and neutron flux. Further, it is well known that pressure tubes of cold-worked Zr-2.5Nb materials result in hydrogen diffusion, which create fully-hydrided regions (frequently called Blister). Thus a proper investigation of hydrogen diffusion within zirconium-alloy nuclear components, such as CANDU pressure tube and fuel channels is essential to predict the structural integrity of these components. In this respect, this paper presents numerical investigation of hydrogen diffusion to quantify the hydrogen concentration fur blister growth of CANDU pressure tube. For this purpose, coupled temperature-hydrogen diffusion analyses are performed by means of two-dimensional finite element analysis. Comparison of predicted temperature field and blister with published test data shows good agreement.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.769-778
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• 2005

The velocity and pressure fields of a ship's Weis-Fogh type propulsion mechanism are studied in this paper using an advanced vortex method. The wing (NACA0010 airfoil) and channel are approximated by source and vortex panels. and free vortices are introduced away from the body surfaces. The viscous diffusion of fluid is represented using the core-spreading model to the discrete vortices. The velocity is calculated on the basis of the generalized Biot-Savart law and the pressure field is calculated from an integral, based on the instantaneous velocity and vorticity distributions in the flow field. Two-dimensional unsteady viscous flow calculations of this propulsion mechanism are shown. and the calculated results agree qualitatively with the measured thrust and drag due to un-modeled large fluctuations in the measured data.

• Structural Engineering and Mechanics
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• v.67 no.1
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• pp.53-67
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• 2018

The changes of parameters of pressure and velocity of propagation of elastic pressure and shear waves in uniformly deformed solid compressible media are studied within the nonclassically linearized approach (NLA) of nonlinear elastodynamics to create a new theoretical basis of the geomechanical interpretation of various groups of geophysical observational and experimental data. The cases of small and large deformations are considered while their describing by various elastic potentials, i.e., problems considering the physical and geometric nonlinearity. Convenient analytical formulae are obtained to calculate the indicated parameters in the deformed isotropic media within the nonclassical linear and nonlinear solution in the NLA. Specific numerical experiments are conducted in case of overall compression of various materials. It is shown that the method (generally accepted in the studies of mechanics of standard constructional materials) of additional linearization (relative to the pressure parameter) in the basic correlations of the NLA introduces substantial quantitative and qualitative errors into the results at significant preliminary deformations. The influences of the physical and geometric nonlinearity on the studied characteristics of the medium are large in various materials and differ qualitatively. The contribution of nonlinear components to the values of the considered parameters prevails over linear components at large deformations. When certain critical values of compression deformations in the medium are achieved, elastic waves with actual velocity cannot propagate in it. The values of the critical deformations for pressure and shear waves differ within different elastic potentials and variants of the theory of initial deformations.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3518-3523
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• 2007

An analysis program of specific impulse has been developed for a gas generator cycle rocket engine. The program has been verified by comparing the published performance data of the same cycle engine with RP-1 as fuel. A model for pressure drop of regenerative cooling and film cooling mass flow rate has been suggested to satisfy the necessary cooling condition with Jet-A1 as fuel. The engine mixture ratio is defined by the film cooling mass flow rate and the core mixture ratio. The optimal condition of the combustor pressure and engine mixture ratio has been found for maximum specific impulse.

• Journal of the Korea Society of Computer and Information
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• v.20 no.10
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• pp.15-21
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• 2015

In this paper, we propose a stable automatic signature verification algorithm applicable to various smart devices. The proposed algorithm uses real and forgery data all together, which can improve the verification rate dramatically. As a tool for signature acquisition in a smart device, two applications, one using touch with a finger and the other using a pressure-sensing-stylus pen, are developed. The verification core is based on SVM and some modifications are made to include the characteristics of signatures. As shown in experimental results, the minimum error rate was 1.84% in the SVM based method, which can easily defeat 4.38% error rate with the previous parametric approach. Even more, 2.43% error rate was achieved with the features excluding pressure-related features, better than the previous approach including pressure-related features and only about 0.6% more error than the best result, which means that the proposed algorithm can be applied to a smart device with or without pressure-sensing-stylus pens and used for security purposes.

• Food Science of Animal Resources
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• v.30 no.4
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• pp.661-668
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• 2010

This study was carried out to optimize microencapsulation conditions for Inonotus obliquus extract powder with mediumchain triacylglycerol (MCT) using response surface methodology (RSM), and to determine the possibility of adding encapsulated I. obliquus extract to milk toward improving the functionality of milk. and to investigate the effects of added encapsulated I. obliquus extract on the physicochemical and sensory properties of the product. The microencapsulation efficiency of I. obliquus extract powder was investigated with respect to three variables (ratios of core material to coating material, amounts of water added, and spray pressure) in RSM. The optimal conditions for microencapsulation of I. obliquus extract powder were obtained from the ratio of core material to coating material (2.92:10) and the amount of water added (0.5 mL); the spray pressure had an insignificant effect on the microencapsulation (p<0.05). Adding encapsulated I. obliquus extract into milk did not significantly affect either color (L, a and b values) or thiobarbituric acid (TBA) values. Sensory test revealed that there were significant improvements in brownish, herb flavor, and bitterness scores for encapsulated I. obliquus extract-added milk as compared with those for uncapsulated I. obliquus extract-added milk. Based on the data obtained from the present study, it is concluded that microcapsules of I. obliquus extract powder could be applicable to milk without remarkably adverse effects on physicochemical and sensory properties

• Women's Health Nursing
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• v.26 no.4
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• pp.346-357
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• 2020

Purpose: This descriptive phenomenological study aimed to explore the lived experience and meaning of pregnant women's adaptation. Methods: Ten pregnant women from an ongoing Pregnant Couples' Cohort Study agreed to participate in this study. The data were collected through telephone in-depth interviews regarding what they experienced and felt about pregnancy adaptation. The qualitative data were analyzed using Giorgi's method of descriptive phenomenology. Results: Five core situation components were extracted from the raw data, along with 12 themes and 33 focal meanings. The five core situations were 1) first recognizing the pregnancy, 2) pregnancy-related changes, (3) the upcoming birth, 4) the postpartum period, and 5) parenting. The 12 themes were as follows: "anxiety, pressure, and embarrassment due to pregnancy," "efforts to adapt to physical changes," "efforts to adapt to the psychological difficulties of pregnancy," "efforts to adapt to the financial burden and role changes caused by pregnancy," "connecting with the fetus," "adapting to a new marital relationship centering on the baby," "the frustration of childbirth," "fear of childbirth," "postpartum care, need help with lactation planning," "parenting beyond what I imagined," "dad's willingness to participate in parenting," and "career disconnect and consideration of workplace needs." Conclusion: We identified that pregnant women experience adaptation in physical, psychological, relational, and social aspects. The thematic clusters identified can be used to develop nursing interventions to promote women's adaptation to pregnancy.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.11-16
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• 2016

Fuel assembly's mechanical characterization test facility (FAMeCT) in KAERI was constructed with upgraded functional features such as increased loading capacity, underwater vibration testing and severe earthquake simulation for extended fuel design guideline. This facility is designed and developed to provide out-pile fuel data for accident analysis model and fuel licensing. Functional tests of FAMeCT were performed to confirm functionality, structural integrity, and validity of newly-built fuel assembly mechanical test facility. Test program includes signal check of data acquisition system, load delivering capacity using real-sized fuel assemblies and a standard loading cylindrical rigid specimen. Fuel assembly's lateral bending test was carried out up to 30 mm of pull-out displacement. Limit case axial compression loading test up to 33 kN was performed to check structural integrity of UCPS (Upper Core Plate Simulator) support frame. Test results show that all test equipment and measurement system have acceptable range of alignment, signal to noise ratio, load carrying capacity limit without loss of integrity. This paper introduces newly constructed fuel assembly's mechanical test facility and summarizes results of functional test for the mechanical test equipment and data acquisition system.

• Journal of Korean Biological Nursing Science
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• v.18 no.1
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• pp.51-59
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• 2016

Purpose: This study was to examine the effects of a footbath program on heart rate variability, blood pressure, body temperature and fatigue of stroke patients with stroke-induced hemiparesis. Methods: A non-equivalent control group pretest-posttest design was used. Participants were 40 stroke patients, twenty for the footbath program and twenty for the control group, who were hospitalized in a long-term rehabilitation hospital in G city of Korea, from February to April 2014. The twenty participants in the experimental group received the intervention of footbaths and an educational program focused on the prevention of stroke complications; Collected data were analyzed by the IBM SPSS WIN 20.0 program using a t-test, ${\chi}^2$ test, Mann-Whitney U test and repeated measures ANOVA. Results: Significant differences were found in heart rate variability, systolic blood pressure, hand and foot temperatures and fatigue between the two groups. But no significant differences were found in diastolic blood pressure, core temperatures, forehead temperatures, and hand temperatures between the two groups. Conclusion: The footbath program was an effective intervention for skin temperature change and fatigue reduction for stroke patients. Therefore, it is recommended that the footbath program can be utilized as an effective nursing intervention for stroke patients in long-term rehabilitation care hospitals.