• 융복합기술연구소 논문집
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• 제8권1호
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• pp.21-25
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• 2018

We developed nano-porous $TiO_2-SiO_2$ composites (commercial name : PTI, porous titania insulator) with low thermal conductivity as thermal insulating material as well as function of photocatalyst. The objectives of this paper are, firstly, to evaluate of the thermal conductivity of the PTI powder in the temperature range from -160 to $250^{\circ}C$, secondly to evaluate of thermal conductivities of insulation materials that is applied PTI powder. The structure of the PTI powder that has the pores size of 20-30 nm and the particle diameter of 2-10 nm. The PTI had a high surface area of $400m^2/g$ and a mean pore size of $45{\AA}$, which was fairly uniform. The thermal conductivity was measured by GHP(guarded hot plate) method and HFM(heat flux method). The PTI structure is a three-dimensional network nano-structures composed by a pearl-necklace that involved a precious stone in the center of the necklace. The thermal conductivities of PTI-PX powder by the GHP and HFM were 0.0366 W/m.K, 0.0314 W/m.K at $20^{\circ}C$, respectively. This is similar to values that are proportional to the square of the absolute temperature of the thermal conductivity of static air. The thermal conductivities of insulating sheets coated with PTI powder were similar results with that of the PTI powder.

• 한국의류학회지
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• 제33권5호
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• pp.701-710
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• 2009

This study was conducted to develop excellent insole with good thermal insulation using new materials. We investigated that aerogel/fiber composite can be used as padding materials of shoes by comparing surface shape, moisture regain, water vapor permeability, thermal insulation and compression rate of insole materials tried with nonwoven fabric padding materials and insole sold in market. The results are as follows. Surface shapes were shown that the most appropriate material for sealing aerogel/fiber composite was high density fabric as per size of particle of aerogel. Moisture regain of aerogel/fabric composite was better than nonwoven fabric padding samples. However, when compared to insole sold in market, its moisture regain was worse than those of insole merchandises. Water vapor permeability was higher in material padded with nonwoven fabric than materials padded with aerogel/fiber composite in all three kinds of sealing fabrics. Thermal conductivity of aerogel/fabric composite was lower than nonwoven fabric material regardless of sealing fabrics. Thermal insulation of aerogel/fiber composite was higher than padding material of nonwoven fabric regardless of sealing fabrics. Compression rate of nonwoven (SP1) was higher than that of aerogel/fiber composite (SP2). Compressive elastic recovery rate of SP1 was also higher than that of SP2, which its compression rate and compressive elastic recovery rate were both poor. As the above result, ultra porous aerogel/fiber composite were proved to be material of good thermal insulation with lower thermal conductivity and also compression rate was proved to be low. Therefore, we can say that aerogel/fiber composite have high possibility to be used as insole materials for cold winter shoes requiring good thermal insulation protection.

• 설비공학논문집
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• 제22권6호
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• pp.361-368
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• 2010

Due to the insulation and the air-tightness requirement in modern buildings have resulted NBS(New Building Syndrome) and SBS(Sick Building Syndrome) of IAQ problems. Therefore, energy efficient way of solving such IAQ issues are of major concern in these days and building industries. This paper introduces a method to improve thermal performance with a DI(Dynamic Insulation) concept. The characteristic of the dynamic insulation is that the lower U-value as the higher air velocity through the DI in a micro level. A thermal performance monitoring study has been conducted to show the energy impact of porous DI over the static insulation material. The results show that up to 45% could be improved in the case with DI compared to the conventional insulation.

• 한국초전도ㆍ저온공학회논문지
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• 제12권3호
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• pp.49-54
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• 2010

This paper presents apparent thermal conductivity of various powder at different vacuum levels for cryogenic insulation. Four kinds of powder insulator are examined by using boil-off calorimetry at pressure range from 50 Torr to 3 mTorr. The first material is perlite which is widely used in cryogenic application. Microsphere is the second one that is recently proposed as a replacement powder for liquid hydrogen storage tanks. It is a hollow sphere made of silica with the diameter in the order of 10 to $100{\mu}m$. Popped rice and polystyrene beads are also selected as candidates for powder insulation even though they are polymers. With their porous elliptic and spherical configuration and light density, they demonstrate fairly good thermal insulation performance at pressure range from 50 Torr to 3 mTorr. According to the experimental investigation in this paper, microsphere and polystyrene beads possess promising insulation characteristic as powder insulators and further study is desired.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.854-856
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• 1992

The molten carbonate fuel cell has conspicuous features and high potential in being used as an energy converter of various fuels to electricity and heat. However, the MCFC which use strongly corrosive molten carbonate at 650 [$^{\circ}C$] have many problems. This study has examined fabricating methods and specimen characteristics of porous anode electrode.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.756-759
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• 2003

It is increasing the interest on the comfortable dwelling environment and the efforts to solve the problem of the floor impact noise in apartment houses have been realized, as a result numerous products have been made. The purpose of this study is to investigate the sound insulation performances according to foaming rate of floor impact noise insulators and flooring coverings in Mock-up Test Room. The test results of impact insulation performance for each floor impact noise insulators is that double structure of insulator is excel than one in low-middle frequency band and as foaming rate go up, the sound insulation performance is improved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.357-358
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• 2009

본 연구는 경량성, 단열성이 좋은 팽창질석을 혼합한 경량기포콘크리트를 제작하였으며 Al분말을 첨가하여 경량화에 따른 경량기포콘크리트의 단열성능의 상승을 확인함으로서 친환경적인 건축용 단열 내장재의 개발 가능성을 확인해 보았다.

• 한국분말재료학회지
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• 제21권5호
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• pp.389-398
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• 2014

Macroporous ceramics with tailored pore size and shape could be used for well-established and emerging applications, such as molten metal filtration, biomaterial, catalysis, thermal insulation, hot gas filtration and diesel particulate filters. In these applications, unique properties of porous materials were required which could be achieved through the incorporation of macro-pores into ceramics. In this article, we reviewed the main processing techniques which can be used for the fabrication of macroporous ceramics with tailored microstructure. Partial sintering, replica templates, sacrificial fugutives, and direct foaming techniques was described here and compared in terms of microstructures and mechanical properties that could be achieved. The main focus was given to the direct foaming technique which was simple and versatile approach that allowed the fabrication of macro-porous ceramics with tailored features and properties.

• 한국건축시공학회지
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• 제16권6호
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• pp.529-534
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• 2016

칼슘실리케이트계 무기단열소재는 주원료로 시멘트를 90%를 사용하는 다공성 무기단열소재이다. 기존 무기단열소재와 달리 고온의 수화반응 처리가 없기 때문에 가격이 저렴하며, 불연소재의 원료를 사용하여 화제의 위험성도 적다. 칼슘실리케이트 단열소재는 $0.13g/cm^3$의 밀도와 0.050W/mK이하의 우수한 열전도도를 갖는 단열소재이다. 칼슘실리케이트 단열소재는 경량화 될수록 내부 기포를 다량 함유해야 하며 기포를 다량 함유함에 따라 단열성 또한 우수해진다. 본 연구에서는 다량의 기포를 함유하며 일정강도발현을 목표로, 칼슘실리케이트계 무기단열소재의 주성분인 시멘트가 수화반응에 따라 초기 및 장기강도발현하는 특성을 이용하여 칼슘실리케이트계 무기단열소재에 적용하여 물리적 특성을 알아보고자 하였다.

• 한국해양공학회지
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• 제28권6호
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• pp.517-526
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• 2014

The leakage of cryogenic LNG through cracks in the insulation membrane of an LNG carrier causes the hull structure to experience a cold spot as a result of the heat transfer from the LNG. The hull structure will become brittle at this cold spot and the evaporated natural gas may potentially lead to a hazard because of its flammability. This paper presents a computational model for the LNG flow and heat diffusion in an LNG insulation panel subject to leakage. The temperature distribution in the insulation panel and the speed of gas diffusion through it are simulated to assess the safety level of an LNG carrier subject that experiences a leak. The behavior of the leaked LNG is modeled using a multiphase flow that considers the mixture of liquid and gas. The simulation model considers the phase change of the LNG, gas-liquid multiphase interactions in the porous media, and accompanying rates of heat transfer. It is assumed that the NO96-GW membrane storage is composed of glass wool and plywood for the numerical simulation. In the numerical simulation, the seepage, heat diffusion, and evaporation of the LNG are investigated. It is found that the diffusion speed of the leakage is very high to accelerate the evaporation of the LNG.