• Journal of the Society of Naval Architects of Korea
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• v.46 no.5
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• pp.471-478
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• 2009

The present paper deals with characteristics of resistance performance according to the variation of synthetic ice thickness and hull form. The resistance test has been conducted with pack ice condition in Pusan National University towing tank. Stem angle has been chosen as main parameters for the variation of hull form characteristics, which is the most important factor especially in icebreaking cargo vessel. The serial comparisons of resistance test have been done with the variation of hull form parameter as well as with the different thickness of synthetic ice. The different trend of resistance performances with increasing of stem angle has been shown at each synthetic ice thickness. The present test results is expected to be confirmed by comparing the test results in ice tank in the near future.

• Journal of Life Science
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• v.27 no.5
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• pp.584-590
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• 2017

Antifreeze proteins (AFPs) bind to ice crystals and inhibit their growth. AFPs are essential for the survival of organisms living in subzero environments. Type I AFP (AFP37) isolated from winter flounder is an ${\alpha}$-helical peptide of 37 residues long. In this study, we attempted to develop short AFP fragments with higher activity and solubility. We designed and synthesized N-terminal 15 and 21 residue-long AFPs, designated AFP15 and 21. Also dimerized AFP15 and 21, designated dAFP15N and dAFP21N, respectively, were generated through disulfide bonds between peptides containing CGG residues added to the N-terminus of AFP15 and AFP21 (designated AFP15N and 21N). Their helical contents and antifreeze activities were assessed using circular dichroism (CD) spectroscopy and a nanoliter osmometer, respectively. The helical content of AFP15 AFP21, AFP15N, AFP21N, dAFP15N and dAFP21N was 47, 48, 23.8, 28, 49.1, and 52%, respectively compared to that of wild type AFP37; the antifreeze activity was 8.4, 9.3, 0.05, 5.6, 12.1, 11.2% respectively, compared to that of wild type AFP37. Contrary to our anticipation, the dimerized peptides showed almost the same antifreeze activity as their monomeric counterparts. These results indicate that the dimerized peptides behave as monomeric peptides due to the high rotational freedom of disulfide bonds connecting two monomeric peptides. The star-shaped ice crystals generated by the peptides also demonstrated weak interaction between ice and peptides.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.933-944
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• 2019

This study analyzes the tide deformation of land boundary regions on the east (Region A) and west (Region B) sides of the Ross Ice Shelf in Antarctica using Double-Differential Interferometric Synthetic Aperture Radar (DDInSAR). A total of seven Sentinel-1A SAR images acquired in 2015-2016 were used to estimate the accuracy of tide prediction model and Young's modulus of ice shelf. First, we compared the Ross Sea Height-based Tidal Inverse (Ross_Inv) model, which is a representative tide prediction model for the Antarctic Ross Sea, with the tide deformation of the ice shelf extracted from the DDInSAR image. The accuracy was analyzed as 3.86 cm in the east region of Ross Ice Shelf and it was confirmed that the inverse barometric pressure effect must be corrected in the tide model. However, in the east, it is confirmed that the tide model may be inaccurate because a large error occurs even after correction of the atmospheric effect. In addition, the Young's modulus of the ice was calculated on the basis of the one-dimensional elastic beam model showing the correlation between the width of the hinge zone where the tide strain occurs and the ice thickness. For this purpose, the grounding line is defined as the line where the displacement caused by the tide appears in the DDInSAR image, and the hinge line is defined as the line to have the local maximum/minimum deformation, and the hinge zone as the area between the two lines. According to the one-dimensional elastic beam model assuming a semi-infinite plane, the width of the hinge region is directly proportional to the 0.75 power of the ice thickness. The width of the hinge zone was measured in the area where the ground line and the hinge line were close to the straight line shown in DDInSAR. The linear regression analysis with the 0.75 power of BEDMAP2 ice thickness estimated the Young's modulus of 1.77±0.73 GPa in the east and west of the Ross Ice Shelf. In this way, more accurate Young's modulus can be estimated by accumulating Sentinel-1 images in the future.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2136-2149
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• 1992

The natural convection from an inclined ice flat plate immersed in cold water near its density maximum is studied numerically. Finite difference analysis has been performed for the heat and momentum transfer with respect to various inclined angles and ambient water temperatures. The results of the analysis are presented for ambient water temperatures, 1.0deg. C. leq. T／sub .inf.／.leq. 15.0deg. C and the inclined anales from 0deg to 60deg. They include velocity profiles, temperature profiles, melting velocities, and mean Nusselt numbers for entire flow fields, Generally, in the range of 0deg. C .leq.theta. .leq. 60.deg. C, the results show three distinct flow regimes, In the range of 1.0 deg. C .leq. T／sub .inf.／ .leq. 4.6 .deg. C, the greatest mean Nuselt number exists about 3.0deg. C. In the range of 5.7deg. C .leq. T／sub .inf.／ .leq. 15.0deg. C, mean Nuselt number increases as ambient water temperature increases. Also, the mean Nuselt number decreases as the inclined angle increases. This theoretical results are compared with previous experimental ones and multiple steady state ones.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.11
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• pp.944-951
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• 2018

Artificial icing test and wind tunnel test can be performed to reduce the development period when a rotorcraft is required operation under icing situations. Artificial icing test of the KUH(Korean Utility Helicopter) was performed in advance to verify anti-icing and de-icing performance before natural icing test. Although high-precision sensor, the CCP(Cloud Combination Probe) is used to measure icing test condition parameters such as LWC(Liquid Water Content) and MVD(Median Volume Diameter), the measured values need to be verified in various methods due to the possibility of uncertainties which are the test atmosphere environment, sensor errors, and etc. The calculated LWC from the ice thickness cumulated on the fuselage of the KUH is compared to the measured value by CCP, and the results show the effective indirect method to check the test conditions.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.117-127
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• 2019

Vessel's ice speed performances will be verified in ice sea trial but environmental conditions of ice fields are changeable according to the weather condition of ice trial area. Speed performance has to correct in the no wind, wave and current etc. after sea trial. Especially finding ice fields which is exact the same as owner's ice thickness and strength requirements is not easy. Therefore speed correction according to environment condition has to be done after sea trial measurements. Correction methods for ice thickness, ice strength, wave, wind and ship draft, trim, ice drift etc. are checked in ice sea trial based on literature review such as ISO standard, ITTC recommendation, journal papers and proceedings of conferences. Possibility of application for current and ice drift correction in ice field are discussed and measuring schemes and procedures of correction methods are described in this paper. All of correction schemes are calculated for 'Araon' which is ice breaking research vessel with Arctic and Antarctic ice field test results. Analyzed results shows that Araon is satisfied with her official ice speed performance of 3 knots with 10MW power at 1m ice thickness, 570kPa ice flexural strength.

• Journal of Energy Engineering
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• v.9 no.3
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• pp.178-183
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• 2000

본 연구에서는 유동과 냉각수를 이용하는 아이슬러리 제조관정을 관찰하고, 이 시스템의 가장 큰 문제점인 관내동결 특성을 파악하였다. 시험수로는 수도수(city water)를 이용하였다. 시스템을 순환하는 시험수가 제빙관내에서 $0^{\circ}C$ 이하의 과냉각 조건이 형성되어 제빙관을 빠져 나오면서 축냉조에 설치된 충격판상에서 과냉각 해소가 일어났다. 이때 유동과냉각수는 내부에너지를 방출하면서 그 일부가 얼음 입자로 상변화되었고, 나머지는 실험장치를 계속순환하였다. 제빙관에서 시험수와 브라인의 열교환 방식을 대향류와 평행류 두 조건에서 시험수의 과냉각도는 Reynolds 수가 증가함에 따라 감소하는 경향을 보였고, 이들 결과 값으로부터 각각의 관계식을 유도하였다. 또한 브라인의 냉각속도가 0.29~0.53[$^{\circ}C$/min] 범위에서 시험수의 과냉각도는 브라인 냉각속도에 종속되지 않았다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.379-381
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• 2011

2010년 3월 22일 "Ice Navigation"에 대한 경험과 자료 수집을 위하여 통영항(평택항)과 Sakhalin "Prigorodnoye항"을 운항하는 대한해운 소속의 "K. Jasmine"호를 승선하여 "Prigorodnoye항"에서 LNG $143,700M^3$를 선적하여 "통영항"에서 양하하는 과정을 경험하고 하선하였다. "K. Jasmine"호는 년 150만톤의 LNG 수입을 위한 "한국 ${\leftrightarrow}$ Sakhalin Project"에 투입된 LNG운반선으로서 "Russian Maritime Register of Shipping"의 "Ice Class LU2" 증서를 갖고 있는 선박이다. 이 증서는 선박이 60Cm 두께의 얼음 해역에서 Ice Breaker의 인도 아래 4Knots 이상의 선속을 유지할 수 있음을 보장받고 있다. 운항중 SEIC(Sakhalin Energy Investment Company)에서는 Ice map을 매일 제공하는 하고 있었으며, 이를 참조하여 본선에서는 계획된 항해를 수행하였다. 이 논문에서는 Ice Navigation선박의 성능 조건에 대하여 검토하여 향후 이 항로에 취항하는 선박에 지침이 되고자 한다.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.457-464
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• 2011

This paper deal with the validation of correction method of ice strength and thickness to the sea trial condition based on the ice model test results. It is very difficult to conduct the model test corresponding to the sea trial condition exactly. In addition, the available sea trial data is not sufficient for the validation of correction method. In the present study, the model test results of Terry-Fox ice breker have been used to compare the corrected results of sea trial test by varying its thickness and strength of model ice. The HSVA and ITTC methods have been applied to the present comparisions and the required power has been also validated by using the HSVA method. There are rather good agreement between the sea trial result and model test corrected by the HSVA and ITTC method. The more comparisons are expected to be carried out in near future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.3
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• pp.167-174
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• 2017

Antarctica, where ice sheet has been declined rapidly, should be monitored periodically. However, there are difficult to access for local survey or aircraft observation due to the vast and extreme environments of the polar regions. In order to overcome this problem, there have been a lot of studies by acquiring radar or laser data by satellite. It is also difficult to accurately measure the changes of the surface where is composed of snow or ice layer, and it is also difficult to product a high-resolution DEM. This study therefore aims to product DEMs of two periods using high-resolution KOMPSAT-3A stereo images, and DEM matching is implemented by the LZD(Least-squares Z-Differences) method to detect DEM changes in both periods. As a result, the proposed method could be suggested as comparing height differences of the two DEMs within 1m precision.