• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.6
• /
• pp.169-177
• /
• 2017

Recently, as the size of transportation vessels has increased, there is a growing need for securing the front-water depths of existing port facilities. The method of deepening front-water depth is securing the depth of the port facility, and it is reinforced by grouting after excavating the rubble-mound to the required depth. The purpose of this study is to investigate the reinforcing performance and filling performance of thixotropic grout as a grouting material for reinforcing rubble-mound. Compressive strength tests were carried out for two types of thixotropic grout, and 5 specimens with a diameter of 400 mm and a height of 530 mm were manufactured and evaluated for filling performance. The required strength of reinforced rubble-mound required to ensure the safety of the structure is 6 MPa. All the thixotropic grouts used in this study were found to satisfy the required strength over 9 MPa at 7 days of age. As a result of visual observation of filling state of the filling performance test specimens, it was confirmed that the thixotropic grout was well filled up to the desired fillet height.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.4D
• /
• pp.587-592
• /
• 2006

The joint sealants used in the airside should resist the high temperature of the jet blast and the jet fuel oil spilled when the aircraft is maintained and filled. The material of joint sealant for the airside should be different from that for the road due to these characteristics. Three different kinds of the joint sealant materials were tested in this paper. The materials include the polysulfide, the polyurethane and the silicon. The test results show that the physical properties and the performance of the polysulfide show the high resistance to the jet blast and the jet fuel oil. When the characteristics of the airside considered, the polysulfide may apply in the both of the runway and the apron area, the polyuretane can be applied the taxiway. The use of the silicon sealant is not recommended for the airside.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.1
• /
• pp.130-135
• /
• 2010

In this study, the performance improvement of epoxy resin system had been tried by the improvement of particle size distribution and globularization of filler using polymerization method. From the results of particle size distribution measurement, the polydispersity value of reformed filler was 1.04 and that of silica flour before reformation was 2.6, it could be confirmed that the particle size uniformity of reformed filler had been improved greatly and the shape of particle was globular. Compatibility between monomer and silica was improved remarkably with the silanization pretreatment of silica flour. From the results of degree of crosslinking test, it could be confirmed that the binding structure of reformed filler was 3-dimensional net structure. And it could be also confirmed that the fluidness was improved at the casting of epoxy resin with reformed filler. From the above results, it could be concluded that the reformation of filler with the improvement of particle size distribution and globularization was very successful method to improve the performance of cast epoxy resin system.

• Proceedings of the KSR Conference
• /
• 2006.05b
• /
• pp.432-437
• /
• 2006

• Solar Energy
• /
• v.19 no.4
• /
• pp.45-53
• /
• 1999

This report Introduces a total heat exchanger in a solar air-conditioning system using Lithium Chloride(LiCl) solution. The hot and humid outside air is cooled and dehumidified by LiCl solution that is sprayed on the packed layer of the total heat exchanger. LiCl solution once diluted is concentrated again in a regenerator using solar energy. Three types as the packed materials were used in this experiment and the dehumidification performance was evaluated by the value of $k_xa(kg/h{\cdot}m^3{\cdot}{\Delta}x)$, overall mass transfer coefficient based on a humidity ratio potential difference, the influence of inlet LiCl solution flow rate, air flow rate, packed layer height on $k_xa$ was investigated. It was found that air flow rate, LiCl solution flow rate, packed layer height for all types had a great influnce on the value of $k_xa$.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.29-30
• /
• 2010

In this study, inorganic filler is used to improve the flexural strength of RC beam with GFRP instead of epoxy in wet condition. The flexural strength of RC beams was investigated by different condition with reinforcing frames and anchors dimension.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.5
• /
• pp.144-152
• /
• 2010

In this study, cement-based filler is used as an adhesive instead of organic adhesive, epoxy because there were problems under wet condition. First, the bond strength of cement-based filler was measured and the result was satisfied with KS F 4716. However, in case of wet condition, bond strength of epoxy adhesive decreased $0.73N/mm^2$ in 7 days and $0.84N/mm^2$ in 14 days from pilot test. This implies that there would be a problem on reinforced concrete structure in wet condition, such as tunnel and sewage box. In the second experiment, the flexural strength of RC beams with GFRP using different thickness of cement-based filler was investigated, and the result was indicated 113%, 66%, 75% increase in 10mm, 20mm, 30mm thickness, respectively. From the result, it was known that 10mm filler thickness produces stable bond performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.225-226
• /
• 2007

나노 기술은 21 세기에 들어와 모든 산업에 고루 이용되며 미래를 이끌어 나갈 기숱로 평가되고 있다. 고압 회전기용 주절연재료의 개발에서도 에폭시에 나노충진제를 혼합하여 복합재료로 만드는 나노기술이 활용되고 있으며, 이러한 나노기술을 바탕으로 절연성능을 높이고, 열적, 기계적 안정성을 높이는 기술 개발에 관심을 기울이고 있다. 하지만 이러한 성능향상을 위해서는 반드시 에폭시 기지 내에 충진제가 골고루 분산되어야 하며. 에폭시의 점도로 인해 제조 과정에서 발생하는 기포의 생성은 시료의 제조에 큰 영향을 끼치게 된다. 본 연구에서는 이러한 점에 착인하여 무충진 시료와 제조과정에서 혼입될 수 있는 불순물, 족 분산을 위한 유기 용매를 제조과정에서 고의로 혼합하여 이에 따른 기계적/유전적 특성과 엉항를 살펴보았다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1600-1604
• /
• 2015

As modern houses are constructed with high-density and high-insulation, there is benefit to reduce energy consumption, but there are many side effects raised from polluted air. To solve the problem, a ventilation system is used to improve a indoor air quality. In this research, we experimentally estimate ventilation performance of HRV(heat recovery ventilator) with heat-pipe according to working fluid filling quantity and ventilation. Heat-pipe used in this study was designated separately to be applied to a ventilation system. The working fluid was R22, which was filled from 40 to 55 (%vol.) by 5(%vol.). Ventilation based on the front velocity was measured from 0.3 m/s to 1.5 m/s by 0.3 m/s intervals. Refrigerant filling quantity with the highest efficiency was found to depend on the ventilation. From this study the optimal refrigerant filling quantity in accordance with the ventilation of the detachable heat pipes was found experimentally.

• Korean Journal of Materials Research
• /
• v.5 no.1
• /
• pp.87-95
• /
• 1995

The effect of stuffing of TiN on the diffusion barrier property between A1 and Si was investigated. The stuffing of TiN was performed by annealing in a Nz ambient at $450^{\circ}C$ for 30min. By TEM analysis, it is identified that there are solid-free or open spaces of a b u t 10-20$\AA$ between the grains of asdeposited TiN. In the case of stuffed TiN, the width of solid-free or open spaces has been reduced to about 10$\AA$ or below. The combination of RBS and AES analyses showed that the asdeposited TiN had about 7at.% of oxygen, and that the stuffed TiN had about 10-15at.% of oxygen. The diffusion barrier test result shows that after annealing at $650^{\circ}C$ for lhour, the asdeposited TiN fails due to the formation of A1 spikes and Si pits in the Si substrate. However, in the case of stuffed TiN, there is no indication of Al spikes and Si pits at the same annealing condition. Thus, it is concluded that this stuffing of TiN significantly improves the diffusion barrier property of TiN between A1 and Si. It is considered that the stuffing effect results from the reduced diffusion through grain boundaries due to the reduced spacing of grain boundaries.