• The KSFM Journal of Fluid Machinery
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• v.19 no.5
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• pp.50-60
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• 2016

A design methodology of the modeled test facility to conserve an injection performance of a passive safety injection system is proposed. This safety injection system is composed of a core makeup tank and a safety injection tank. Individual tanks are connected with pressure balance line on the top side and injection line on the bottom side. It is important to conserve the scaled initial injection flow rate and total injection time since this system can be operated by small gravity head without any active pumps. Differential pressure distribution of the injection line induced by the gravity head is determined by the vertical length and elevation of each tank. However, the total injection time is adjustable by the flow resistance coefficient of the injection line. The scaling methodology for the tank and flow resistance coefficient is suggested. A key point of this test facility design is a scaling analysis for the flow resistance coefficient. The scaling analysis proposed on this paper is based on the volume scaling law with the same vertical length to the prototype and can be extended to a model with a reduced vertical length. A set of passive injection test were performed for the tanks with the same volume and the different length. The test results on the initial flow rate and total injection time showed the almost same injection characteristics and they were in good agreement with the design values.

• Journal of Hydrogen and New Energy
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• v.24 no.4
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• pp.340-346
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• 2013

Study on clean and efficient utilization technology for low rank coal with high moisture content is actively ongoing due to limited reserves of petroleum and of high grade coal and serious climate change caused by fossil fuel usage. In the present study, supercritical water gasification of low rank coal was performed. With increasing reaction temperature, content of combustible gases such as $H_2$ and $CH_4$ in the syngas increased while the $CO_2$ content decreased. As the reaction pressure increased from 210 to 300 bar, the $CO_2$ content in the syngas increased while the hydrocarbon gas content decreased. The $H_2$ and $CH_4$ content in the syngas increased slightly with pressure. With the addition of Pd, Pt, and Ru catalysts, it was possible to improve the production of $H_2$. Moreover, the increase of active metal content in the catalyst increased the $H_2$ productivity. The Ru catalyst shows the best performance for increasing the $H_2$ content in the syngas, while decreasing the $CO_2$ content.

• Journal of Hydrogen and New Energy
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• v.29 no.1
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• pp.41-55
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• 2018

General polymer electrolyte fuel cell (PEMFC) operates at less than $80^{\circ}C$. Therefore liquid phase water resulting from electrochemical reaction accumulates and floods the cell which in turn increases the mass transfer loss. To prevent the flooding, it is common to employ serpentine flow channel, which can efficiently export liquid phase water to the outlet. The major drawback of utilizing serpentine flow channel is the large pressure drop that happens between the inlet and outlet. On the other hand, in the high temperature polymer electrolyte fuel cell (HT-PEMFC), since the operating temperature is 130 to $180^{\circ}C$, the generated water is in the state of gas, so the flooding phenomenon is not taken into consideration. In HT-PEMFCs parallel flow channel with lower pressure drop between the inlet and outlet is employed therefore, in order to circulate hydrogen and air in the cell less pumping power is required. In this study we analyzed HT-PEMFC's different flow channels by parallel computation using previously developed 3-D isothermal model. All the flow channels had an active area of $25cm^2$. Also, we numerically compared the performance of HT-PEMFC parallel flow channel with different manifold area and Rib interval against the original serpentine flow channel. Results of the analysis are shown in the form of three-dimensional contour polarization curves, flow characteristics in the channel, current density distribution in the Membrane, overpotential distribution in the catalyst layer, and hydrogen and oxygen concentration distribution. As a result, the performance of a real area fuel cell was predicted.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1875-1877
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• 2001

Glaucoma is an eye disease which is caused by abnormal high lOP (Intra Ocular Pressure). High lOP is caused by the aqueous humor which is produced consistently but not drained due to malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are some methods to treat glaucoma, Among these, the use of implants is increasing in these days due to many problems In other methods. However, conventional implants are passive implants and have critical disadvantage. Therefore, it is needed to develop an active implant which is composed of a valve actuator, pressure sensor, controller, and power supply. In this paper, we make experiment with the fabricated valve actuator in In-vitro experiment, and estimate the in-vivo result using the experimental result and investigate the possibility of the fabricated valve.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.2
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• pp.77-88
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• 1984

By investigating the characteristics of various factors about soil and pile containing in the theoretical equations of lateral earth pressures acting on a row of passive piles which have been already presented in the previous. papers, the equations are arranged as a simple form which is convenient to use. The simplified equation is examined so as to be also utilized to single passive pile. And a discussion is carried out on the method how to apply the equations to field. As the result of this study, the equations can be arranged as a simple linear equation with the coefficients of lateral force $K_{p1}$ and $K_{p2}$. And the simple linear equation is composed of cohesion c and earth pressures ${\sigma}_H$ acting on backside of pile's row against the direction of soil deformation. In order to apply this equation to field, the active earth pressure can be considered as the earth pressure ${\sigma}_H$. The validity of this consideration is justified by comparing the theoretical values of lateral earth pressures acting on piles with the values observed in field.

• Physical Therapy Rehabilitation Science
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• v.8 no.4
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• pp.210-217
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• 2019

Objective: This study was conducted to compare the immediate effect of hamstring stretching techniques of static stretching, proprioceptive neuromuscular facilitation (PNF) hold-relax and PNF irradiation on the hamstring muscle. Design: Three-group pretest-posttest design. Methods: Fifty-one subjects with shortened hamstrings were randomly assigned to the static stretching group (n=17), PNF hold-relax group (n=17), and the PNF irradiation group (n=17). All subjects performed an active knee extension (AKE) test to assess for the lower extremity with a shortened hamstring. The static stretching group performed stretches by lifting their leg to the maximum extent (3 times, 30 seconds). The PNF hold-relax group performed maximal isometric contraction against the experimenter's resistance (3 times, 10 seconds). The PNF irradiation group performed maximum isometric contraction against the experimenter's resistance toward the direction of the body (5 times, 5 seconds). The pre and post-tests measured range of motion (ROM), pressure pain thresholds (PPT) and muscle tone. Results: There were significant differences in ROM and PPT between pre and post intervention in each group (p<0.05). There was a significant difference only in the ROM among groups (p<0.05). Post-hoc analysis showed that the changes in ROM occurred in the order of the PNF hold-relax group, static stretching group and PNF irradiation group (p<0.05). Conclusions: The findings of this study suggest that the PNF irradiation technique may improve ROM and may be used to improve ROM similar to other stretching techniques. Therefore, the PNF irradiation technique could be included in stretching programs and can be used as a suitable stretching method depending on the situation.

• Research in Community and Public Health Nursing
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• v.17 no.2
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• pp.210-222
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• 2006

Purpose: This study was performed to identify the health status, healthy behavior, and health promotion program needs of day time and shift time industrial male workers at an workplace. Method: Relevant data were collected from June 20 to August 18, 2005. Questionaries were distributed to all subjects along with their medical records of 2005 and 151 sets of responses were used for the analysis. Collected data were analyzed using SPSS WIN 10.0. Result: 1. Health Status - day time and shift-time workers had significant differences in obesity ($x^2=8.38$, p<.01) and blood pressure ($x^2=-2.17$, p<.05). 2. Healthy Habits - Full-time and part-time workers had significant differences in regular meals (63.83, p<.01), preferred foods ($x^2=7.10$, p<.05), and sleep time (t=-3.55, p<.01). They also had significant differences in exercising ($x^2=13.11$, p<.01), exercising time (minutes) (t=-2.25, p<.01), and use of fitness centers ($x^2=7.02$, p<.05). 3. They also had significant differences in their needs of health programs ($x^2=8.66$, p<.01). Conclusion: This study revealed that day time and shift-time workers had differences in obesity and blood pressure, as well as differences in eating sleeping, and exercising patterns. Both groups needed 'fitness programs' more than any other types of health programs and picked 'weight loss' and 'stress control' programs for other options. Industrial nurses should be able to create appropriate health programs for each group based on the above results and induce the workers' active participation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2767-2772
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• 2013

Balance is the foundation for all active daily livings. Evaluation of balance has been conducted to measure postural sway of center of pressure(COP). The purpose of this study is to introduce the Balancia and to examine the validity and inter-, intra-reliability for measure of balance with stroke patients. COP was measured by Wii balance board. The subjects Participated in this study were 39 stroke patients. Intra- and inter-reliability was examined using intraclass correlation coefficient(ICC) with 95% confidence interval. In the result of intra- and inter-reliability, all COP parameters of postural sway showed high to very high reliability with ICC=.793-.939 and ICC=.791-.955. Validity was determined by correlation with Accusway force plate. There were high validity with ICC=.851-.955 between tools. According to these results, the Balancia showed high validity and reliability. It is a useful clinical tool for evaluating balance in stroke patients.

• The Korean Journal of Community Living Science
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• v.25 no.1
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• pp.5-18
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• 2014

This study examines the changes in the physicochemical property and antioxidant activity of six types of vegetables (carrots, crown daisy, mugwort, cabbages, onions, and garlic) based on heat-treated cooking. According to the results, proximate contents (crude protein, fat, and ash) were lower in blanched samples than in untreated samples. Untreated cabbages showed the highest level of total dietary fiber content, which decreased by blanching and increased by high-temperature/high-pressure (HTHP) treatment. Noteworthy is that, in the case of soluble dietary fiber, blanched crown daisy and mugwort showed significantly high levels of 12.0 g and 7.3 g per 100 g(dry basis). There was no significant change in tocopherol content in heat-treated samples. The highest levels of total polyphenol and flavonoid content were 6.73 g and 5.51 g per 100 g, respectively, in the mugwort sample with HTHP treatment at $130^{\circ}C$ for 2 h. The water extract of mugwort with HTHP treatment had the strongest antioxidant effect based on three bioassays (SOD, DPPH, and ABTS). These results indicate the relative correlation between the level of physiologically active content and antioxidant activity and suggest new insights into ingredients for developing functional foods.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1210-1215
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• 1999

Optimum conditions of the hydrogenation of PNA to pure PPD were determined in a three-phase slurry reactor with suspended Pd/C catalyst particles. Minimization of mass transfer resistances at the interfaces of both gas-liquid and liquid-catalyst particles and control of overall reaction rate on catalyst surface leaded to decrease the hydrogen starvation on reaction active sites and to reduce the side reactions during hydrogenation. The optimum temperature, pressure, and catalysst concentration were confirmed to be in the range of $60^{\circ}C$, 60~70 psig, and 1~2 g-cat/L, respectively. Reaction rate was zero order with respect to the concentration of PNA and 1st order with respect to the pressure of hydrogen(P). Overall rate expression of the reaction was $R_A=6.44{\times}10^6{\cdot}H{\cdot}P{\cdot}m{\cdot}$exp(-4659/T) where H is constant, m is concentration of catalyst, and T is temperature.