• Magazine of the Korea Concrete Institute
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• v.4 no.3
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• pp.157-166
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• 1992

해수환경하의 콘크리트 구조물은 동결융해의 반복에 의한 물리적인 침식과 해수중에 용존하는 각종의 이온들의 침투로 인한 화학적 침식에 의해 현저한 성능저하현상을 나타내는 것으로 알려져있다. 본 연구는 포졸란계 혼합재인 플라이 애쉬, 슬래그, 슬리카 흄과 폴리머계 혼합재인 Ethylene Vinyl Acetate(EVA), Styrene-Butadiene Rubber(SBR)를 사용하여 제조한 콘크리트 경화체의 해수환 경하에서 동결융해 저항성에 미치는 혼합재의 종류 및 첨가량의 영향, W/C의 영향을 비교 검토한 실험적 연구이다. 콘크리트의 동결융해 저항성을 위해서는 공기연행이 필수적이며, 공기연행시킨 경우 W/C가 낮을수록 동결융해 저항성이 우수하였다. 해수중에서의 동결융해 저항성은 슬래그분말을 첨가할 때 우수하였으며, 폴리머계 혼합재에서는 EVA가 우수한 결과를 나타내었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.865-870
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• 2008

The effects of exhaust gas recirculation (ECR) on smoke emissions in heavy duty diesel engine are numerically studied by using KIVA-3V CFD code. For the analysis, RNG k-$\varepsilon$ turbulence model was given as a governing equation, and mathematical models of Tab, Wave, Watkins-Park, Nagle-Strikland were applied to describe physical process of droplet breakup, atomization, wall impingement and smoke respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.215-216
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• 2010

This study investigated the development of high durability concrete under an oceanic region through the examination and comparison of the fundamental property and diffusion of chloride ion to apply a high durability admixture on the concrete.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1503-1504
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• 2015

배전용 케이블은 수트리 억제, 화재예방, 경제성 등을 고려하여 구조와 재질이 지속적으로 변경되고 있다. 변경되는 추세를 살펴보면 경제성 측면에서 도체의 재질은 동에서 알루미늄으로 변경되었고, 수트리 억제를 위해 절연체의 재질은 XLPE에서 TR-XLPE로 변경되었다. 또한 외피의 재질도 난연성을 강화하고 수분침투를 억제하기 위하여 난연성 PE로 개선하였다. 중성선도 외부반도전층 위에 올려진 구조에서 외피 내부로 들어가는 충실형 구조로 변경되었다. 이와 같이 외피구조가 변경되면서 외부반도전층의 두께가 증가되었고 이로 인해 접속재 시공시 삼각형 모양의 공극이 커지게 되었는데, 본 논문에서는 케이블의 외부 반도전층 두께 증가가 접속재 부분방전에 미친 영향을 고찰하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.140-141
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• 2000

금속으로 코팅한 광섬유는 폴리머로 코팅한 광섬유에 비해 여러 가지 장점을 가지고 있다. 금속 코팅 광섬유는 열적, 화학적 안정성이 높고 고온에서 사용할 수 있으며 수분 침투에 강하고 높은 굽힘 강도를 가진다. 또 납땜을 할 수가 있어서 광섬유 소자 패키징에 있어서 매우 유리하다$^{(1)}$ . 장주기 광섬유 격자는 WDM 용 필터, 온도 및 변형도 센서, 광섬유 증폭기의 이득 평탄화 필터에 많은 유용성을 가지고 있다. 광섬유 격자를 소자로 사용하기 위해서는 재 코팅이 필수적인데 금속은 좋은 대안이 될 것이다. 금속을 재 코팅 재료로 사용하기 위해서는 금속 코팅이 격자에 미치는 영향에 대한 연구가 요구된다. 광섬유 격자 쌍은 단일 장주기 격자에 비해 분해능이 좋아 센서 및 필터 등에 유용하여 본 연구에서는 광섬유 격자쌍 위에 은을 코팅하여 투과 스펙트럼에 미치는 영향을 알아보았다. (중략)

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10b
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• pp.44-58
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• 2001

FRP(Fiberglass Reinforced Plastic)관을 이용한 사면보강은 천공 후 그라우트재에 압력을 가하여 그라우트재의 천공홀 충전뿐만 아니라 지반으로의 침투주입 효과를 일으켜, 전체적인 보강력 증대를 기대하는 공법이다. 이런 특성을 설계에 반영하기 위해서는 구조재료인 FRP관 자체에 의한 지반보강효과 뿐만 아니라 그라우팅에 따른 지반강도의 증진효과를 정량적으로 평가하는 것이 선행되어야 하나 아직까지는 이에 대한 연구가 부족한 실정이다. 따라서 대상지반을 토사와 암반사면으로 구분하여 각각의 보강효과를 확인하고자 현장시험 및 수치해석을 실시하였으며, 이로부터 지반종류에 따른 보강특성과 합리적인 설계를 위한 설계인자를 추출하고자 하였다.

• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.477-484
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• 2004

As a part of durability improvement of concrete-structure, penetrating water repellency of liquid type is applied to concrete surface. Besides, a related standard is made recently, but the standard has been prescribe for initial settlement state of penetrating water repellency of liquid type, to the exclusion of performance variation depending time and outdoor environment factor. For measurement of performance variation, we measured the weight of outdoor exposure specimen every regular intervals and check a measured value against a measured value of different condition specimen. Moreover, after the application of penetrating water repellent, measured a adhesive strength in tension between cement-polymer modified waterproof coatings and surface of specimen. The applied penetrating water repellent is a emulsified silicon type with a deep penetration depth. In view of the results so far achieved, the more a Quantity of application and active solid content does get, the deeper penetrating water repellency of emulsion type Penetrate get longer and supplied moisture increase in quantity, a penetrating water repellency of liquid type penetrates more deep, but a quantity of water absorption increase gradually. Perhaps this result is caused by a reduction of active solid content on concrete surface, because active ingredient is moved into the concrete by dissolution.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.234-246
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• 2013

It was found that test piece heated rapidly by 3 kW microwave for 5 minutes satisfies the targeted temperature and the percentage of moisture content, and the highest rate of weight increase is obtained in case of 120 minute immersion in the mixture of phosphates and heterocyclic compounds, from the result of such analysis as: kiln drying schedule, flame retardent by flammability test, insect resistance by termites, and permeability of combined penetrant for the wood after assigning multifunctional finish by immersing conifer structural frame, which is used for the frame work of wooden house and indoor/outdoor finishing in flame retardant and insect repellent materials mixture with the remaining heat of microwave. In addition, after a test of flame retardent treated item, it was identified that every mixture of phosphates corresponds with the standards of flame retardent, and upon investigation of moritality of 7 days after putting termites, it was showed that test piece immersed in the mixture of phosphates and heterocyclic compounds has the best characteristics, showing over 96% of high moritality. From the analysis of inward permeability of combined penetrant for the wood, it was decided that excellent performance in the flame retardent and insect resistance of the wood revealed due to full penetration of combined penetrant as it was found that combined penetrant penetrated through the whole inner cells of the wood.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.4
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• pp.1-9
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• 1982

Variation of soil properties is studied by permeating injection of chemical grouts, such as cement type, water-glass type and acrylamide type, to the same soil samples with different densities. Moreover, injection tests using specially prepared equipments of 1.0 shot system and 1. 5 shot system are attempted to investigate permeating injection effects in highly compacted soil and in the presence of ground water. The main factor which causes the improvement of cut-off effect and shearing strength is the cohesion of soil. The strength in the loose state is fundamentally governed by the membrane cohesion, meanwhile, in the loose state is governed by the structural cohesion. Injection effects under the ground water flow is considerably decreased, and effective gelling ratio of approximate 45~80% is observed by variation of velocity and gel time, besides grading of injection materials has high relation with permeation and traveling length but has little relation with effective gelling ratio. Permeating injection effects, such as gelling scope, gelling strength in highly compaoted soil conditions can be confirmed by penetration resistance diagram and iso-strength curve.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.581-588
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• 2022

Purpose: This study is about offering ways of improving existing technical standards in order to propose how to deal with coal deep-seated fire and to increase effectiveness of wetting agent. Method: This study conducts infiltration experiment using eight tons of coal, three types of wetting agents and fire water. And this study analyzes domestic and international technical standards, overseas experimental cases. Result: It is found that two findings are identified; one is fire water cannot infiltrate into the coal due to high level of surface tension, and the other is three types of wetting agent can infiltrate into the coal to the depth of 5~25cm. Also, domestic wetting agent technical standards include measuring surface tension only and testing wood on extinguishing capacity test. On the other hand, this study found that deep-seated fire experiment using cotton, B-class fire test using heptane are used from abroad. Besides it is analyze that capillary rise test, sink test, contact angle measurement are conducted to increase effectiveness of wetting agent at the U.S. Bureau of Mines. Conclusion: Based on standards and cases of U.S. NFPA and Bureau of Mines, this study suggests that domestic technical standards should include adding a new test standard which measures infiltration directly.