• Journal of the Korea Society of Computer and Information
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• v.29 no.3
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• pp.91-98
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• 2024

In this paper, we present a particle-grid blending framework based on a geometric approach to efficiently represent opaque ice spheres with air bubbles. The water temperature is diffused through the grid and the air bubbles represented inside the ice through the particles. To solve the problem of previous methods that generate noisy dissolved air fields, we use levelsets to lighten the algorithm, i.e., the number of active particles and the initial amount of dissolved oxygen can be used to efficiently control the termination conditions of heat diffusion. We also extend the previous dissolved air field method, which only computes near air bubbles, to transparent regions to represent realistic ice spheres, and introduce a levelset-based approach to accurately compute the orientation of particles. As a result, the method presented in this paper is about three times faster than the existing methods and shows visually improved visualization of opaque ice spheres, which can be used in the field of representing physical virtual ice forms.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.12
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• pp.1175-1183
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• 2001

Recently, a great attention has been paid to the ice thermal storage system for the purpose of energy saving and reduction in peak electrical demand. In the present study, it has been investigated the freezing behavior of several kinds of water solutions with nonionic surfactant. In order to prevent ice blockage in a cooled pipe, the amount and wall adhesion behavior of ice of the test fluids were observed experimentally under different concentration of water solution with surfactant, temperature of cooled wall, and the shear velocity of test fluids. The results showed that the size of ice crystal became smaller at higher shear velocity at wall. And the lowest limit of wall adhesion of ice in water solution with surfactant was found at 230 W/$m^2$ of heat flux.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.558-564
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• 2021

The water purifier market has increased rapidly in recent years. The welding technology of the evaporator is a key component that determines the level of ice production and the cold water performance of an ice purifier. The finger type evaporator of an ice purifier can remove ice and is divided largely into an instant heat method and a hot gas method. In the hot gas type evaporator, particularly during the production process, the pinhole phenomenon inside the copper pipe and clogging problems occur intermittently when welding high-pressure pipes due to the high-temperature oxygen welding. Its use in a water purifier can cause a problem in that ice and cold water do not form, and repairs cannot be made on site. To solve this problem, in this study, a cap jig was applied to improve the welding defect of the hot gas evaporator. In addition, the oxygen welding flame size was adjusted so that the heat source could be well supplied to the cap jig, and the effectiveness was confirmed through a wave pressure test, a test, and a thermal shock test.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.699-702
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• 2009

가스하이드레이트(Gas Hydrate)는 특정한 온도와 압력조건하에서 물분자로 이루어진 공동 내로 메탄, 에탄, 프로판 등의 가스가 들어가 물분자와 상호 물리적 결합으로 형성된 외관상 얼음과 비슷한 고체 포유물로 자연상태에 존재하는 하이드레이트의 주 성분이 메탄(Methane)인 경우가 대부분인 까닭에 메탄 하이드레이트라고도 불린다. 표준상태에서 $1m^3$의 메탄하이드레이트는 $172m^3$의 메탄가스와 $0.8m^3$의 물로 분해된다. 그러나 메탄 하이드레이트를 인공적으로 만들경우 물과 가스의 반응율이 낮아 하이드레이트 생성시간이 상당히 길고 가스 용해율도 낮다. 따라서 하이드레이트를 빨리 만들며 가스충진율도 증가시킬 수 있는 방법으로 가스 흡착성이 있는 탄소나노튜브(Carbon Nano Tube)를 기계적 분산방법인 초음파 분산(Dispersion)과 화학적 개질에 의한 분산방법인 산화처리분산을 사용하여 탄소나노튜브와 산화탄화나노튜브를 순수한물에 분산하여 나노유체를 만들고, 나노유체와 메탄가스를 반응시켜 메탄하이드레이트를 생성시키는 실험을 수행하였다. 나노유체와 순수한물의 상평형(Phase Equilibrium)은 비슷하였으며, 탄소나노튜브를 0.0005Vol%를 분산한 나노유체와 순수한물의 메탄가스 소모량의 비교한결과 나노유체의 가스소모량의 순수한물보다 ${\Delta}T_{sub}$=0.5K에서는 2배 ${\Delta}T_{sub}$=9.7K에서는 1.6배 증가하였다. 또한 산화나노유체와 나노유체의 메탄 가스소모량은 산화나노유체가 0.01 ~ 0.02mol정도 높았으나 그 효과가 미미하였고, 교반기를 사용하여 RPM300으로 교반시켰을 경우 역시 메탄 가스소모량은 큰 차이가 없었으나 산화나노유체의 경우 메탄 가스소모량이 나노유체보다 급격히 증가함을 확인하였다.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.147-158
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• 2015

In this study, sewer backfill material was developed to prevent sewer damage and ground subsidence. Laboratory test was performed in the field of CA replacement ratio, accelerator type and replacement ratio and W/M. The compression strength of backfill material was 0.55~0.64MPa below in W/M 70% and 0.20MPa over W/B 80%. Ice block was used to simulate the ground cavity and subsidence caused by sewer damage in application study. The existing sand compaction and the new backfill material was comparative estimated in field. The ground settlement of cross section was 23.4cm and that of longitudinal section was 27cm in sand compaction section, but the ground had not sunk in backfill material section.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.717-729
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• 2005

Peak cooling load of large buildings is generally greater than their peak heating load. Internal and solar heat gains are used fur selection of adquate equipment in large building in cold winter climate like Canada and even Korea. The cost of geothermal heat exchanger to meet the cooling loads can increase the initial cost of ground source heat pump system to the extend less costly conventional system often chosen. Thermal ice storage system has been used for many years in Korea to reduce chiller capacity and shift Peak electrical time and demand. A distribution system designed to take advantage of heat extracted from the ice, and use of geothermal loop (geothermal heat exchanger) to heat as an alternate heat source and sink is well known to provide many benifits. The use of thermal energy storage (TES) reduces the heat pump capacity and peak cooling load needed in large building by as much as 40 to $60\%$ with less mechanical equipment and less space for mechanical room. Additionally TES can reduce the size and cost of the geothermal loop by 1/3 to 1/4 compared to ground coupled heat pump system that is designed to meet the peak heating and cooling load and also can eliminate difficuties of geothermal loop installation such as space requirements and thermal conditions of soil and rock at the urban area.