• Title/Summary/Keyword: R&D 자원

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A Study on the Recovery of Phosphoric acid from Waste acid containing Acetic acid, Nitric acid and phosphoric acid. (초산, 질산, 인산을 함유한 삼원계 폐혼산으로부터 인산 회수에 관한 연구)

  • Lee, Hyang-Sook;Shin, Chang-Hoon;Kim, June-Young;Ahn, Jae-Woo
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • 2005.05a
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    • pp.162-167
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    • 2005
  • 초산, 질산, 인산이 함유된 폐혼산으로부터 인산을 분리하여 재활용하기 위한 방법으로 용매추출법을 이용하였다. 폐혼산에서 초산과 질산을 선택적으로 분리하고, 추출 잔류액에서 인산을 회수하고자 하였다. 주요 실험 변수로는 추출제농도, 교반시간, 교반속도 등의 변화에 따른 초산, 질산, 인산의 추출거동을 조사하였다. 또한, McCabe-Thiele diagram으로부터 초산, 질산 성분의 추출 및 탈거에 필요한 이론적 단수를 조사하였다. 실험결과 인산염계 추출제를 사용할 경우 초산과 실산을 선택적으로 분리 추출이 가능하였으며, 추출제의 함량은 유기상의 50%가 적합하였다. 교반속도와 교반시간의 영향은 크게 없었으며, 상비(A/O)=1/3, 6단에서 초산과 질산을 완전히 추출 분리하여 인산을 추출잔류액에서 회수가 가능하였다.

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Estimation of the Reach-average Velocity of Mountain Streams Using Dye Tracing (염료추적자법을 이용한 산지하천의 구간 평균 유속 추정)

  • Tae-Hyun Kim;Jeman Lee;Chulwon Lee;Sangjun Im
    • Journal of Korean Society of Forest Science
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    • v.112 no.3
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    • pp.374-381
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    • 2023
  • The travel time of flash floods along mountain streams is mainly governed by reach-average velocity, rather than by the point velocity of the locations of interest. Reach-average velocity is influenced by various factors such as stream geometry, streambed materials, and the hydraulic roughness of streams. In this study, the reach-average velocity in mountain streams was measured for storm periods using rhodamine dye tracing. The point cloud data obtained from a LiDAR survey was used to extract the average hydraulic roughness height, such as Ra, Rmax, and Rz. The size distribution of the streambed materials (D50, D84) was also considered in the estimation of the roughness height. The field experiments revealed that the reach-average velocities had a significant relationship with flow discharges (v = 0.5499Q0.6165 ), with an R2 value of 0.77. The root mean square error in the roughness height of the Ra-based estimation (0.45) was lower than those of the other estimations (0.47-1.04). Among the parameters for roughness height estimation, the Ra -based roughness height was the most reliable and suitable for developing the reach-average velocity equation for estimating the travel time of flood waves in mountain streams.