• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.564-570
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• 1997

The most important factor for the desalination system is the fresh water production cost dependent upon the possible energy source which should be obtained easily and with low price. Recently in Korea the demand of LNG, as a cheap and clean energy which does not cause an environmental problem, has sharply been increased. In general, LNG is storaged in a tank as a liquid state below -162 'C. When it is serviced, however, the LNG absorbs energy from a heating source and transforms to the gaseous state with high pressure. During this process a huge amount of cold energy accumulated in LNG is wasted. This waste cold energy can be utilized for producing fresh water from sea water using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique, a qualitative and quantitative data regarding the freezing behavior of sea water is needed in advance. The goal of this study, therefore, are to reveal the freezing mechanism of sea water, to measure the freezing rate, and to investigate the freezing heat-transfer characteristics. The experimental results help to provide a general understanding of the sea water freezing behavior in a Rectangular vessel cooled from below.

• 아시안잔디학회지
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• 제4권1호
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• pp.49-55
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• 1990

Experiments were conducted to investigate the relationships between the soil freezing depth and the accumulated degree-day of temperature below $0^{\circ}C$ at 17 locations during 1989-1990 winter season in kangwon province. The observed results are as follows : 1.When accumulated degree-day of temperature below at was 141t at late January soil freezing depth of sunny place was 46.5cm, that of shaded lot was 59 cm, and that of marginal place sunny or shaded area was 55cm, in Chun cheon. 2.Accumulated degree-day of temperature below at of Dae gwangryong area was more than that of Un-du, whereas soil freezing depth of Dae gwangryong was lower that of Un-du. It was considered that snow covering worked as heat insulator. 3.Soil freezing depth of vinyl mulching on Zoysia turf was less by around 2Ocm than that of non-vinyl mulching. Rice hulls covering of 4Ocm showed the great heat insulation effects with the soil freezing depth of 1.5cm at sunny place and 6.5cm at shaded lot compared to that of 47cm at sunny and 59.5 cm at shaded place bare ground. 4.Among investingated areas, Dunae, Honeg seong gun was the deepest soil freezing, 89cm with $569^{\circ}C$ of accumulated degree-day of temperature below $0^{\circ}C$ at late February. 5.dehydration of Juniperus C. var. Kaizuca, Euonymus japonica, and Chamaecyparis pisifira at winter season was around 5 %, however dehydration of Vinca minor was more than 10 %. A Studies on the Soil Freezing Depth and Change of Moisture contents in evergreen Plants upon subzero Temperature in Kangwon area.(2)

• Journal of Advanced Marine Engineering and Technology
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• 제33권4호
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• pp.443-450
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• 2009

This study has dealt with the ice making characteristics in a rectangular vessel cooled from below direction with experiment and numerical analysis. The experiment and numerical analysis were carried out under the following conditions which are the cooling wall temperatures of -5[$^{\circ}C$], -10[$^{\circ}C$], and -15[$^{\circ}C$]. The temperature profile of non-frozen layer was calculated by numerical analysis as the form of non-dimensional temperature. From this study, it is cleared that the existence of natural convection is clearly known. And also the non-dimensional freezing amount was derived from experimental result. This correlation equation will give a useful information to the designers of ice making system.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.527-534
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• 1997

Freezing of an aqueous sodium cWoride solution (Nacl- H20) saturating a packed bed with ini¬tial salt concentrations of 5, 10, 15(k by weight is investigated experimentally in a rectangular cav¬ity. The system was cooled from the top, bottom and a vertical side wall. For the freezing experi¬ments from below, there was little effect of the initial salt concentration throughout the freezing process, and the global freezing rate was not affected by the initial salt concentration. For the freezing from above, the size of the mush region decreased and the mushlliquid interface became flatter as the initial liquid concentration is decreased. For the freezing from vertical side wall, reheating of the mixture was intensified with an increase in the initial salt concentration. For Ci= 5%, supercooling was observed only at the early times of freezing process, but for Ci= 15% small supercooling was observed throughout the freezing process.

• Journal of Advanced Marine Engineering and Technology
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• 제22권5호
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• pp.680-686
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• 1998

In the adoption of a desalination system the most important factor is the cost of fresh water pro-duction. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$ When it is serviced however the LNG absorbs energy from a heat source and it is transformed to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energycan be utilized to produce fresh water by using a sea water freez-ing desalination system. in order to develop a sea water freezing desalination system and to estab-lish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water in a cooled circular tube to measure the freezing rate and to investigate the freezing heat-transfer characteristics. The experimental results provide a general understanding of sea water freezing behavior in a cooled circular tube.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.873-882
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• 2021

In this study, a study was conducted to develop a system for predicting/responding to black ice occurring on roads in winter. Tests conditions were studied by making models of cement concrete pavement and asphalt concrete pavement. In order to freeze water on the manufactured model package, an tests was conducted at a temperature below zero using a freezer, and the freezing process was photographed using a thermal imaging camera. Black ice is generated when water is present on the road surface and the temperature is below freezing or the road surface temperature is below the dew point temperature. Under sub-zero conditions, the pavement, water, and ice were classified with a thermal imaging camera. As a result of the tests, it was possible to distinguish with a thermal imaging camera at a temperature below freezing in the same freezer due to the difference in the emissivity of the packaging, water, and ice. In the process of changing from water to ice during the tests, it was analyzed that ice and water were clearly distinguished by the thermal imaging camera due to the difference in emissivity and reflectance, so black ice could be predicted using the thermal imaging camera.

• 설비공학논문집
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• 제3권5호
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• pp.386-394
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• 1991

Freezing of saturated porous media contained in a rectangular cavity has been studied experimentally. Water and different diameter glass beads consitituted the liquid and porous media. Solidification front shape, the effects of bead diameter and initial liquid temperature was investigated. When the hot wall temperature was below $4^{\circ}C$, the freezing rate was higher at the top than at the bottom due to the density inversion, but with increasing the hot wall temperature the freezing rate at the top was effected by the liquid temperature and was lower than at the bottom. With increasing the bead diameter, the difference of freezing rate between top and bottom was increased and depends on thermal conductivity. When the liquid temperature was low in the beginning, the freezing rate was high, but with increasing the time almost the same with those of high temperature liquid.

• Journal of Advanced Marine Engineering and Technology
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• 제22권4호
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• pp.529-537
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• 1998

Currently as due to the rapid development of industry and increase in population we meet serious problems concerning the shortage and pollution of water. In the country many experts predict a shortage of water approaching 450 million tons by the year 2006. To cope with this serious problem it is necessary to construct desalination plants. In the adoption of a desalination system the most important factor is the cost of fresh water production,. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$. When it is serviced, however the LNG absorbs energy from a heat source and transforms to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energy can be utilized to produce fresh water by using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance, The goals of this study are to reveal the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water to measure the freezing rate and to investigate the freezing heat-transfer characteristics,. The experimental results will provide a general understanding of sea water freezing behavior in a rectangular vessel cooled from above.

• 한국환경복원기술학회지
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• 제20권1호
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• pp.77-96
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• 2017

This study was carried out to clarify the climatic factors of the freezing injury for the judgement on the adaptation areas of evergreen broad-leaved trees. We surveyed and analyzed the climatic factors of the freezing injury to Machilus thunbergii Siebold & Zucc. on the streets with the analyzation of planting grounds, soil conditions and the surrounding buildings. This study showed that only the minimum air temperature factor out of the other climate elements, which were the annual precipitation; the average annual temperature; the average monthly temperature of january; the average monthly minimum temperature of January; the average temperature of the coldest month; the warmth index and the coldness index, was matched up with the previous theories and reports on the freezing damages on the evergreen broad leaved trees and Machilus thunbergii Siebold & Zucc. The freezing injury of Machilus thunbergii Siebold & Zucc was occurred when the mean minimum temperature of the coldest month(TMC) in winter season fell down below $-4.1^{\circ}C$ and the temperature fell down below $-9.2^{\circ}C$. The freezing damage on Machilus thunbergii Siebold & Zucc surrounded by high buildings were less than those surrounded by low buildings or at non buildings.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.163-168
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• 1994

If the concrete is exposed below freezing point of the outer temperature before hardened, the quality of the concrete will be lowered after hardened. Anti-freezing agent which doesn't corrode the steel bar and doesn't generate the alkali-aggregate reaction by noncholride recently developed in Japan and Northern Europe. But the effects of these agents are rarely known. Therefore, this study is desigend for analyzing the freezing properties at the condition of solution of solution and cement paste. And this study aims to present the reference data for practical use of the concrete works using anti-freezing agent.