• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.11
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• pp.1497-1505
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• 2000

A numerical study is made on the ice-formation for a laminar flow in a curved channel. When the water flows through the curved channel with the walls specified below the freezing temperature, the ice layer has been formed on the curved surface, different from that of a straight channel. The fluctuation of ice layer has been predicted, considering the variation of velocity and temperature near the curved portion of channel. The study also takes into account the interaction existing between the laminar flow and the curved channel. In the solution strategy, the present study is substantially different from the existing works in that the complete set of governing equations in both the solid and liquid regions are resolved. The results from this study have been mainly presented, focusing on the variation of ice layer close to the curved portion. Numerical results have been obtained parametrically by varying the curved angle and the radius of curvature of channel, in addition to the variation of Reynolds numbers and wall temperatures of channel. The results show that the curved shape of channel has the great effect on the thickness of the solidification layer. The wave of ice layer thickness appears in the vicinity of curved portion. This behavior of ice layer has been amplified as is the increasing of curved angle and the radius of curvature of channel. In addition, the ice layer becomes thin as Reynolds numbers in increasing. And also, as the wall temperature of channel increases, the width of channel becomes to be shrunk due to the growth of ice layers in the upper and lower wall of channel.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.663-668
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• 1997

In Korea, the temperature of winter seasons are really severe and cause lot's of snow-falling and iceing in the pavements. Several de-iceing mehtod have generally been adopted to melt the ice on the surface of pavement. Therefore, the Study of experimental in the first stage was given to the verification of the icers's effects. First, Contrete and asphalt pavement specimens were made and scattered with a CaC2-deicers. then 3cm and 5cm thickness of artificial snow were prepared on the surface of specimens. It reveals that the early calorification due to de- icers as high as the temperature of laboratory increases within about 10 minutes and last for more then 2 hours and the test of ice-formation on the surface of contrete and asphalt specimen due to snow leads to the similar rate of freezing time about 20 minutes. Second, three kinds of de-icers, such as CaC2 CaC2+Nacl, Cacl Flaket are rested in the snowy highway to check the iceing-resistance. The CaC2 is proved to be the most effective de-icers so far.

• Journal of the Korean earth science society
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• v.30 no.4
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• pp.454-463
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• 2009

In this study, from January 2006 to February 2009, we observed 107 ice spikes formed in a natural state, and analyzed their environment. We developed an experimental device to reproduce ice spikes in laboratory and successfully made 531 ice spikes. We analyzed the process of the formation and the principle of how those ice spikes grow through videotaped data of the formation in the experiment. In the natural world, when the surface of water and the lower part of a vessel begin to freeze, a vent (breathing hole) develops at the surface where an ice is not frozen; this vent serves as the seed of an ice spike. It is assumed that the volume expansion of ice in the vessel which occurs when water freezes makes the supercooled water go upward through the vent and becomes an ice bar called an ice spike. In the laboratory, however, when distilled water is poured into an ice tray cube and kept in the experimental device for about one and a half hours at a temperature of -12- $-13^{\circ}C$, a thin layer of ice then begins to develop on the surface of the water, the vent is formed, and ice spikes form for about 10-30 minutes. These spikes stop growing when the end becomes clogged. Ice spikes can be described as falling into seven categories of shape, with the apex type topping the list followed by the slant type in the natural state and the vertical type predominating in the laboratory.

• Korean Journal of Remote Sensing
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• v.33 no.6_1
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• pp.901-915
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• 2017

Recently, global climate change has caused a catastrophic event in the Arctic Ocean, directly and indirectly. The air-sea interaction has caused the significant sea-ice reduction in the Arctic Ocean, and has been accelerating the Arctic warming. Many scientists are worried about the Arctic environment change, suggesting that many of anomalous events will produce direct or indirect biophysical effects on the Arctic. The aim of this study is to understand the inter-annual variability of the Arctic Ocean in wide-view using multi-satellite-derived measurements. Sea surface temperature (SST) and sea ice concentration (SIC) data were obtained from Optimum Interpolation Sea Surface Temperature (OISST) and ECMWF ERA-Interim, respectively. Chlorophyll-a concentration (CHL) was obtained from Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and Aqua sensor from MODerate resolution Imaging Spectroradiometer (MODIS-Aqua) sensor which has continuously observed since 1998. From 1998 to 2016 summer in the Arctic Ocean which was defined as regions over $60^{\circ}N$ in this study, there were three consequences that CHL increase ($0.15mg\;m^{-3}\;decade^{-1}$), SST warming ($0.43^{\circ}C\;decade^{-1}$) and SIC decrease ($-5.37%\;decade^{-1}$). While SST and SIC highly correlated each other (r = -0.76), a relationship between CHL and SIC was very low ($r={\pm}0.1$) because of data limitations. And a relationship between CHL and SST shows meaningful results ($r={\pm}0.66$) with regional differences.

• Journal of Environmental Science International
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• v.31 no.4
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• pp.329-339
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• 2022

Better understanding the mechanism of black ice occurrence on the road in winter is necessary to reduce the socio-economic damage it causes. In this study, intensive observations of road weather elements and surface information under the influence of synoptic high-pressure patterns (22^nd December, 2020 and 29^th January, and 25^th February, 2021) were carried out using a mobile observation vehicle. We found that temperature and road surface temperature change is significantly influenced by observation time, altitude and structure of the road, surrounding terrain, and traffic volume, especially in tunnels and bridges. In addition, even if the spatial distribution of temperature and road surface temperature for the entire observation route is similar, there is a difference between air and road surface temperatures due to the influence of current weather conditions. The observed road temperature, air temperature and air pressure in Nongong Bridge were significantly different to other fixed road weather observation points.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.801-809
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• 2019

NASA's lunar polar exploration mission in 2009 confirmed the presence of ice-layer in the permanently shadowed regions (PSR) of the moon. Since then, studies have been actively conducted to evaluate the ground characteristics for exploring the ice-layer in the polar regions of the Moon. In this study, transient heat transfer analysis for the lunar ground was conducted to predict the ground's temperature that varies with the time and location. As a result of the numerical analysis, it was confirmed that the temperature under the lunar ground converged to below the ice sublimation reference temperature (≒112 K) at above 86° latitude. This model enabled us to identify the regions where there is a high possibility of ice being buried. Besides, we found that the ice-layer in the shallow region, where the temperature deviation is significant, makes ground temperature distribution heterogeneous. Lastly, this study suggested the maximum allowable frictional heat of a drill bit that can preserve the phase of buried ice.

• Journal of the korean society of oceanography
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• v.33 no.1-2
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• pp.1-7
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• 1998

In the western Weddell Sea, winter mixed layer is characterized by near-freezing temperature and higher salinity due to brine injection through sea-ice formation. This layer becomes Winter Water being capped by warmer and less saline Antarctic Surface Water during the sea-ice melt-ing season. In this study, Winter Water was preliminarily identified by the oxygen isotopic com-positions. The ${\delta}^{18}$O values of Winter Water show the progressively increasing trend from south to north in the study area. It presumably reflects the enhanced mixing with Antarctic Surface Water due to the extent of influence by low S'"0 value of sea-ice/glacier meltwater. Correlations between salinity and 6'"0 values of seawater can be used to more generally characterize Winter Water with a view to identification. However, the prediction on the degree of mixing from these relationships needs more detailed isotope data, although this study allows the oxygen isotopic composition of seawater as a tracer to identify the water mass.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.66-72
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• 2013

The demand for an ice class ship is rising expected to rise according to the increase of energy consumption and the opening of arctic sea routes. Ice class ship should be designed to cope with the severe environmental conditions of arctic sea such as a high mechanical impact and abrasion damage, caused by pack ice, ice bergs and low temperature. The ice class ship hulls are coated with an anti-abrasion and low friction coating such as a solvent free epoxy or high solid-volume epoxy. These coatings require two-component heating pump and a high grade surface preparation. In this study, the coating performances for the arctic vessels, such as puncture absorbed energy, abrasive wear loss, friction coefficients and impact absorbed energy were evaluated. Based on this study, a proper coating performance specification for the arctic vessels was proposed and coating selection guideline in terms of coating performance and workability was also established.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.327-336
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• 2019

The caldera lake "Chun-ji" is located at the summit of Baekdu volcano, which is in the border of China and North Korea. Chun-ji Lake has altitude 2,189 m above sea level. The Chun-ji is freezing in the winter when the water temperature goes down to zero for a year, and it melts in the season when the water temperature goes up again. However,since it is located at a high altitude, there are many cloudy days, and it is difficult to observe with optical images. For this reason, radar images, which are less influenced by weather than optical images, are more effective for observing the ice of heaven and earth. In this study, 75 TerraSAR-X images from chun-ji area were used for analysis from 2015 to 2017, and the calculated ice area and temperature changes were analyzed. As a result, the ice of the caldera lake formed was formed in early December and slowly melted until mid-April. During this period, temperatures in the Samjiyeon area were about $-10^{\circ}C$ when ice was produced, and the temperature was about $0^{\circ}C$ in mid-April when it was thawing. Correlation coefficients between ice surface area and temperature in winter 2015 and 2016, where global ice is produced,show a high correlation of -0.82 and -0.75. In addition to the results of this study, it can be used as an indicator to monitor the volcanic activity by comparing the result of the recent volcanic activity with the result of the increase in water temperature using various imagery.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.10
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• pp.1210-1216
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• 2011

The purpose of this study is to establish the analysis method for prediction of temperature during cryogenic heat treatment. Experimental cryogenic heat treatment is conducted to observe the phenomena such as boiling of fluid, ice layer on the material surface and to measure the temperature distribution of Al6061 tube. The CFD analysis considering the observed phenomena in the experiment is performed to predict the temperature distribution and convection heat transfer coefficient at each stage of cryogenic heat treatment, in which the boiling of fluid is considered as the multi-phase condition of vapour and liquid. The formation of ice layer on the tube surface is also modeled between material and fluid. The predicted results are in good agreement with the experimental ones. From the results, it is shown that the analysis method can predict the temperature distribution and convection heat transfer coefficient during cryogenic heat treatment.