• Title/Summary/Keyword: 거품

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Remote Sensing of Wave Trajectory in Surf Zone using Oblique Digital Videos (해안 디지털 비디오를 이용한 쇄파지역에서의 파랑궤적 측정)

  • Yoo, Je-Seon;Shin, Dong-Min;Cho, Yong-Sik
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.4
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    • pp.333-341
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    • 2008
  • A remote sensing technique to identify trajectories of breaking waves in the surf zone using oblique digital nearshore videos is proposed. The noise arising from white foam induced by wave breaking has hindered accurate remote sensing of wave properties in the surf zone. For this reason, this paper focuses on image processing to remove the noise and wave trajectory identification essential for wave property estimation. The nearshore video imagery sampled at 3 Hz are used, covering length scale(100 m). Original image sequences are processed through image frame differencing and directional low-pass image filtering to remove the noise characterized by high frequencies in the video imagery. The extraction of individual wave crest features is conducted using a Radon transform-based line detection algorithm in the processed cross-shore image timestacks having a two-dimensional space-time domain. The number of valid wave crest trajectories identified corresponds to about 2/3 of waves recorded by the in-situ sensors.

Examination of the Ground Remote Monitoring System for Coastal Environmental Elements - Marine Radar and Camera System - (연안 환경 요소에 대한 지상 원격 관측 방법 고찰 - 마린 레이다와 카메라 시스템 관측을 중심으로 -)

  • Kim, Tae-Rim;Jang, Seong-Woo
    • Korean Journal of Remote Sensing
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    • v.27 no.4
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    • pp.403-410
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    • 2011
  • Consistent observation with high temporal and spatial resolution is required for an efficient monitoring of coastal environments. Remote monitoring system installed on the ground is capable of simultaneous observation of wide coastal area and consistent observation with high frequency, which a small number of in-situ measurements cannot manage. This paper studies two typical ground based coastal monitoring system, marine radar and camera system. Marine radar can produce time series of frequency spectrum by integrating wave number spectrum calculated from spatial and temporal variation of waves in the radar image. The time averaged radar images of waves can analyze wave breaking zone, rip currents and location of littoral bars. Camera system can observe temporal variation of foam generation originated from coastal contamination as well as shoreline changes. By extracting the part of foams from rectified images, quantitative analysis of temporal foam variation can be done. By using the two above systems of different characteristics, synergetic benefit can be achieved.

Phosphorylation of silk fibroin and its properties (견 피브로인의 인산화와 그 특성)

  • 문장희;김정호;배도규;신봉섭
    • Journal of Sericultural and Entomological Science
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    • v.43 no.2
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    • pp.116-124
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    • 2001
  • To improve the functional properties as a food, silk fibroin was phosphorylated with STMP In the phosphorylation reaction of silk fibroin, the degree of phosphorylation was increased with high alkali index and treatment temperature. Depending on treatment time and concentration of STMP it was rapidly increased up to 1hr. and 50%, but slowly above that time and 100%. It was indicated in the results of FT-IR analysis and $\^$31/p NMR spectroscopy of phosphorylated fibroin that it had a close ∝-helix and poly-phosphate structure. The more phosphorylation of fibroin made more turbidity, foam expansion and foam stability, but less solubility. Emulsifying activity was increased up to P100, but slightly decreased above Pl00 and emulsifying stability was constantly increased on the progressing of phosphorylation.

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Extraction of Natural Emulsifier from Medicago sativa L. and Sapindus saponaria L.: Optimization using CCD-RSM (알팔파 및 무환자나무열매로부터 천연유화제의 추출: CCD-RSM을 이용한 최적화)

  • Hong, Seheum;Lee, Seung Bum
    • Applied Chemistry for Engineering
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    • v.33 no.3
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    • pp.272-278
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    • 2022
  • In this study, natural emulsifiers were extracted from Medicago sativa L. and Sapindus saponaria L. The extraction yield using CCD-RSM and the extraction process of foaming stability of the extracted product were optimized and 95% confidence interval was used to confirm the statistical reasonableness of the optimization. Herein, independent parameters were the ethanol volume and extraction temperature, whereas reaction parameters were the extraction yield and foaming stability. Under the condition of 53.5 vol% ethanol and extraction temperature (70.9 ℃), the maximum yield and foaming stability of the extracted product from Medicago sativa L were predicted as 26.2 wt% and 44.5%, respectively. In the case of the extraction from Sapindus saponaria L, the maximum yield and foaming stability were expected to be 31.9 wt% and 47.5% under the optimized conditions including 60.4 vol% of ethanol and extraction temperature (72.4 ℃). The average experimental error for validating the accuracy was about 3.4(± 0.3)% and 5.0(± 0.04)% for the extraction processes from Medicago sativa L. and Sapindus saponaria L., respectively.