• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.549-554
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• 2003

EPRI PPM (Performance Prediction Methodology), a method used for the prediction of required thrust of valves, can not be applied to unbalanced-disk globe valves operated in the fluid when the fluid temperature is above $150^{\circ}F$ because the thrust increase caused by the friction between the valve disk and body is not considered in the PPM. In order to apply PPM to the valves, EPRI suggested new friction prediction method to be added in the code. This paper analyzes the applicability of the prediction method comparing the disk-to-body friction load predicted from the method with the measured friction load from the field tests. The maximum values from the prediction method and those obtained from the test were 268lbs and about 1500lbs, respectively. It is included that the prediction method should be improved for the realistic prediction of disk-to-body friction load.

• KIEAE Journal
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• v.7 no.5
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• pp.65-71
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• 2007

The purpose of this study was to analyze the difference of thermal sensation by radiant floor heating as ecological design element. The experimental investigations were carried out in climate chamber, and subjects were 34 college-age females in good health. The experimental variable was radiant heat by floor heating, and experimental controlled conditions were indoor temperature, relative humidity, and air velocity in climate chamber and clothing value and activity of subjects. The results are as follows. (1) Indoor temperature($21{\pm}0.5^{\circ}C$) in climate chamber were maintained as controlling. Clothing values of the subjects were controlled as average 0.73 clo. In the floor heating-off, globe temperature was average $23.2^{\circ}C$(22.4~24.1), but in the floor heating-on, globe temperature was average $24.8^{\circ}C$(23.0~25.5). (2) In the floor heating-off, thermal sensation rating was average -1.03(slightly cool), in the floor heating-on, thermal sensation rating was average +1.03(slightly warm). (3) There were the differences of thermal sensation by radiant floor heating although indoor temperatures were maintained in an equal state. (4) The thermal sensation rating was tending upward according as the globe temperature was getting higher.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.734-739
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• 2016

The globe valve is a linear motion valve that is designed primarily to stop, start, and regulate flow. The disk of a globe valve can be removed totally from the flow path or it can completely close the flow path. In this study, numerical analysis using ANSYS-CFX was initially performed to predict the flow coefficient and build a prototype model of a globe valve. The flow coefficient is the volume of water at $15.6^{\circ}C$ that will flow per minute through a valve with a pressure drop of 1 psi across the valve. In other words, it is an important factor for determining the size of the valve. From the analysis results, the fluid flux of water and flow coefficient of the valve were extracted. From the numerical results, a prototype of ultra-fine precision control valve, which can regulate the fluid flow of range 0 ~ 0.1 gal per min, was developed. The experimental results were compared with the numerical results using the flow coefficient ($C_v$) graph. From the comparative results, the flow coefficient ($C_v$) error percentage between the numerical and experimental results was very low, which is acceptable, proving that the proposed prototype model is convincing. In addition, it is possible to predict the flow coefficient using only numerical analysis.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.25-30
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• 2010

This experiment was carried out to investigate the effect of planting times on the growth and yield of artichoke (Cynara scolymus L.) in non-heated greenhouse in Jeju Island ($33^{\circ}28.110N,\;126^{\circ}31.076E$), Korea. Five transplanting dates (from Feb. 25 to Apr. 30) of the first half of the year and six transplanting dates (from July 30 to Dec. 15) of the second half of the year were compared. In the spring cycle, most of the flower buds emerged from May to June, and the emergence was slightly earlier in 'Imperial Star' than in 'Green Globe'. The earliest harvest on June 16 was 'Imperial Star' which was planted on Feb. 25. The highest yield of 856 kg/10a was observed in 'Imperial Star' which was planted on Feb. 25. Transplanting of the first half of the year, it was impossible to harvest in the same year when the planting was done after April 15 since the flower buds were not emerged. The flower buds emerged from late Feb. to middle April of the following year in the all planting times of the second half of the year. It was possible to harvest the first time in early April. The highest yield was 2,127 kg/10a in 'Green Globe' which was planted on July 30, and the yields decreased as the planting times were delayed. In the comparisons of planting times of artichoke, it would be recommendable to plant artichoke on Feb. 25 for the same year harvest and in July 30~Oct. 15 for the following year harvest in Jeju Island non-heated greenhouse cultivation.

• Proceedings of the Korean Society for Environmental Edudation Conference
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• 1996.12a
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• pp.40-46
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• 1996

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.3-10
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• 2005

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.403-416
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• 1996

Global natural vegetation mapping (GNVM) system was developed for estimating potential forest area of the globe. With input of monthly mean temperature and monthly precipitation observed at weather stations, the system spherically interpolates them into 1°×1°grid points on a blobe, converts them into vegetation types, and produces a potential vegetation map and a potenital vegetation area. The spherical interpolation was based on negative exponential function fed from the constant radius stations with oval weighing method which is latitudinally elongated weighing in temperature and longitudinally elongated weighing in precipitation. The temperature values were corrected for altitude by applying a linear lapse-rate (0.65℃ / 100m) with reference to a built-in digital terrain map of the globe. The vegetation classification was based upon Koppen’s sKDICe. The potential forest area is estimated for 6.96 Gha (46.24％) of the global land area (15.05 Gha).

• Journal of the Korean housing association
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• v.10 no.1
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• pp.75-84
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• 1999

The purpose of this study is to identify the characteristics of the thermal environment, and to analyze the relationship between the thermal reactions and the skin temperatures in the lying position in the radiant floor heating system. The results are as follows: 1) The globe temperature was nearly equal to the operative temperature in the room. 2) The floor surface temperature and the globe temperature were 26.4$^{\circ}C$ and 23.6$^{\circ}C$, respectively when the whole body temperature was at neutral point. 3) The mean temperature of the six skin parts was 31.3$^{\circ}C$ (cold thermal environment); 34.1$^{\circ}C$ (neutral thermal environment); 35.1$^{\circ}C$ (hot thermal environment).

• The KSFM Journal of Fluid Machinery
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• v.10 no.1 s.40
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• pp.41-48
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• 2007

The effect of the upstream flow conditions on the disc stability of the swing check valves was investigated at various upstream flow disturbance sources and distances from the tested check valves. The experimental loop was designed and installed to measure the disc positions, disc back stop load, and differential pressure at flow velocities lot 3 inch and 6 inch swing check valves. The selected disturbance sources are elbow and globe valve. The effect of the disc fluctuation is different depending on the type of disturbance and the distance between the disturbance and the check valve. Disturbances generated by elbow and globe valve located upstream from check valve create greater and more violent disc motion than uniform flow.

• The KSFM Journal of Fluid Machinery
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• v.6 no.4 s.21
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• pp.29-37
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• 2003

This study was undertaken to verify the effect of flow coefficient when a globe control valve was attached by different type of fitting. The valve flow coefficient is usually determined by measuring the flow rate and the pressure drop with the connection of straight pipe through the valve. The effect of different fitting that is mounted on the downstream of the valve is studied. Four types of fittings and three distances between the valve and a downstream fitting are compared parametrically to investigate the effect on the flow coefficient of it. Measured flow coefficient and numerically predicted value by using computational fluid dynamics were compared in detail. It is concluded that the flow coefficient is reduced if the fitting is attached after a valve, but the effect of different type of fitting is not crucial.