• Title/Summary/Keyword: dew

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Flood Forecasting for Pre-Release of Taech'ong Reservoir (대청댐 예비 방류를 위한 홍수 예보)

  • Lee, Jae-Hyeong;Sim, Myeong-Pil;Jeon, Il-Gwon
    • Water for future
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    • v.26 no.2
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    • pp.99-105
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    • 1993
  • A practical flood forecasting model(FFM) is suggested. The output of the model is the results which the initial condition of meteorological parameters and soil moisture are projected on the future. The physically based station model for rainfall forecasting(RF) and the storage function model for runoff prediction(RP) are adopted respectively. Input variables for FFM are air temperature, pressure, and dew-point temperature at the ground level and the flow at the rising limb(FRL). The constant parameters for FFM are average of optimum values which the past storm events have. Also loss rate of rainfall can predicted by FRL.

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Study of Characteristics of Hot Dip Galvanized Steel Strip by Oxygen-free Finishing (비산화성 분위기에 의한 용융아연도금의 특성 연구)

  • 진영구;김흥윤
    • Journal of the Korean institute of surface engineering
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    • v.28 no.5
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    • pp.300-308
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    • 1995
  • The effect of nitrogen finishing for the control of coating weight in a nitrogen sealing box on the coating surface property in hot dip galvanizing process has been studied. The coated surface is free of oxide marks and edge overcoated. The coating uniformity is excellent ; the standard deviation of the coating thickness along width of the specimen was $1~1.2\mu\textrm{m}$ in the box whereas $2.5~3\mu\textrm{m}$ in the air. Considering surface quality of the coating such as oxide mark, edge overcoated and zinc dust, the oxygen content between 40 and 200 ppm was suggested in the box in addition the oxygen content of at least 40 ppm or the minimum dew point of $-27^{\circ}C$ is required to prevent a zinc vaporization.

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The Study of Alumina Ceramic to Metal Bonding (알루미나 소결체와 금속간의 접합에 관한 연구)

  • 김종희;김형준
    • Journal of the Korean Ceramic Society
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    • v.15 no.2
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    • pp.89-97
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    • 1978
  • The basic mechanism of adherence in sintered high purity alumina ceramic-to-metal bonding was studied. Emphasis was placed on flux composition, porosity of the fired ceramics, and metallizing mixtures. The study was conducted on 95 and 99.5% alumina, using molydbenum-manganese, molybdenum-manganese-silicon dioxide metallizing compositions. Metallizing was performed in wet hydrogen (dew point, +17$^{\circ}C$) at 145$0^{\circ}C$ for 45min. This experiment indicated that adhernece mechanism of ultra high purity alumina ceramic was attributed to formation of $MnAl_2O_$4, and in the case of 95% alumina containing glass, the migration of glass from the interface into the void of the metal coating was the main role to the adhrence. It showed also that greater the bond-strength was resulted as porosity was increased.

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On Characteristics of Sea Breeze Front observed in Pusan Coastal Area, Korea (부산연안역에서 관측된 해풍전선의 특성)

  • 전병일
    • Journal of Environmental Science International
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    • v.6 no.6
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    • pp.629-636
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    • 1997
  • We have analyzed focusing on the characteristics, speed and width of sea breeze front in Pusan coastal area using the meteorological data observed at Kimhae air force meteorological station because the presence of the front has Important effects on the dInstributlon of air pollution. The inland penetration of sea breeze front was recognized by steep variation of meteorological parameters(wind direction, wind speed, temperature, dew point temperature, air pressure, relative humidity) before and after its passage and the variation of $SO_2$ concentration, the speed and width of the sea breeze front was 2.07m/s and 217m, respectively. The structure and inland penetration of sea breeeze front should be taken into account whenever a model is to be compared with detailed field measurements.

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A Study on Anti-Condensation of the Apartment Building in Summer (공동주택의 하절기 결로 방지에 대한 연구)

  • Kim, Seung-Beum;Seo, Hee-Chang;Kim, Joo-Heyng;Kim, Jae-Jun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.17-18
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    • 2012
  • Moisture condensation leading to defects that occur repeatedly in the winter, and recognize the same method, the problem of the other buildings in the same area again and again, a vicious cycle that occurs due to the temporary lack of systematic research and processing way of coping has been recurring. In this study, as warming progresses, more inside the air-conditioned summer season due to an increase in the ambient temperature of the condensation phenomenon to happen about summer wall condensation phenomena are expected to analyze the case of a building to prevent condensation and for insulation designs are proposed.

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A Consideration on Improvement of Safe Lithium Battery Air Transportation (리튬 전지의 안전한 항공 운송을 위한 개선 방향 고찰)

  • Joe, Hunmyung
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.25 no.3
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    • pp.135-142
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    • 2017
  • As PED(Personal Electronic Device) market has been rapidly grown, the demand on Lithium battery, which is most commonly used power source of PED, also has been increased. Dew to this trend, the amount of Lithium battery air transportation is also increasing. However, it should be treated very carefully because Lithium is one of very explosive metal. So ICAO, IATA and civil aviation agencies try to enhance the safety of Lithium battery air transportation by aircraft certification and operating regulations. To enhance in-flight safety, the aircraft for transporting Lithium battery should equip certified fire extinguishing system. But recent studies find that Halon, currently used extinguishing agent, is not effective on extinguishing Lithium battery fire. Besides, there is no certified Halon replacement for air use and no acceptable specific minimum performance standard(MPS) for Lithium battery fire. For this issue, a study on characteristics and establishing MPS of Lithium battery fire is needed for safe air transportation of Lithium battery.

A Study of Dew Condensation Characteristics to Switchboard due to Environmental Conditions (환경 조건변화에 따른 배전반 결로 특성에 관한 연구)

  • Kim, Jae-Dol;Oh, Kab-Suk
    • Proceedings of the KAIS Fall Conference
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    • 2011.12b
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    • pp.540-542
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    • 2011
  • 본 논문은 결로 방지 기능을 가진 배전반 개발을 위해 다양한 온습도 환경 조건에서 결로의 생성 및 제거에 관한 특성을 파악하였다. 획득된 결과는 외부 온도변화에 따라 배전반 내부의 온도도 변화되며, 내외부의 온도차는 일정한 차이를 나타내었다. 결로 생성의 특성은 초기에는 미세한 분무상에서 시간이 경과함에 따라 주위 물방울들과 결합하여 성장하며, 최종적으로는 표면장력이 작용하지만 중력에 의해 하부로 처지면서 떨어지는 과정으로 진행되었다. 또한 히터 등으로 결로 생성조건을 파괴시키면 생성시와 동일한 온습도 조건이 유지되어도 결로는 제거되는 것을 알 수 있었다.

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The Characteristics of a Bypass Air Conditioning System for Load Variation (부하변동에 대한 바이패스 공조시스템의 특성)

  • 김보철;신현준;김정엽
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.3
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    • pp.240-246
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    • 2002
  • Bypass air conditioning systems are divided into three types; an outdoor air bypass, a mixed air bypass and a return air bypass system. What makes the return air by pass system more effective is that it directs all of moist outdoor air through the cooling coil. The bypass air conditioning system can maintain indoor R.H (Relative Humidity) less than a conventional CAV (Constant Air Volume) air conditioning system by adjusting face and bypass dampers at part load. When a design sensible load (the ratio of sensible load to total sensible load) is 70 percent (at this time, RSHF (Room Sensible Heat Factor) . 0.7), indoor R.H was maintained 59 percent by the return air bypass system, but 65 percent by the conventional CAV air conditioning system (valve control system). The bypass air conditioning system can also improve IAQ (Indoor Air Quality) in many buildings where the number of air change is high.

Characteristics of Reinforced Dewaxed Hanji after Aging (강도보강 처리 탈랍지의 특성)

  • Kim, Kang-Jae;Lee, Min-Hyung;Eom, Tae-Jin
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2011.04a
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    • pp.73-79
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    • 2011
  • The annals of Joseon Dynasty has been known as one of the UNESCO's Memory of the World Heritage. Some of the annals of Joseon Dynasty was composed with wax coated book. Especially the waxed book have been severely damaged by various reason. To find out the safety preservation method of the annals of Joseon Dynasty waxed book, the characteristics of reinforced dewaxed Hanji was evaluated in this paper. From strength properties of MC treated dewaxed Hanji after dewaxing with different method, dewaxing ratio was been high, polymer treated dew axed Hanji showed a better strength. As the aging time, polymer layer on dewaxed Hanji was became brittle and cracked.

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Meteorological Data Integrity for Environmental Impact Assessment in Yongdam Catchment (용담댐시험유역 환경영향평가의 신뢰수준 향상을 위한 기상자료의 품질검정)

  • Lee, Khil-Ha
    • Journal of Environmental Science International
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    • v.29 no.10
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    • pp.981-988
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    • 2020
  • This study presents meteorological data integrity to improve environmental quality assessment in Yongdam catchment. The study examines both extreme ranges of meteorological data measurements and data reliability which include maximum and minimum temperature, relative humidity, dew point temperature, radiation, heat flux. There were some outliers and missing data from the measurements. In addition, the latent heat flux and sensible heat flux data were not reasonable and evapotranspiration data did not match at some points. The accuracy and consistency of data stored in a database for the study were secured from the data integrity. Users need to take caution when using meteorological data from the Yongdam catchment in the preparation of water resources planning, environmental impact assessment, and natural hazards analysis.