• 한국지반공학회논문집
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• 제27권12호
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• pp.5-15
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• 2011

본 연구는 매립지의 최종복토층으로 사용되는 점토 혹은 지오멤브레인의 부등침하 및 기상조건변화에 의한 균열에 취약한 점을 고려하여 균열 발생시 자가형성된 물질로 인하여 균열치유 작용을 할 수 있는 SRSL(Self Recovering Sustainable Liner)의 매립지 최종복토층으로서의 적용성을 파악하였다. SRSL 기법은 2개의 층을 두어 상, 하부층 사이 계면에 불투수성 물질을 생성하는 동시에, 균열발생 시에도 2가지 성분이 다시 결합하여 불투수성 물질을 재형성하는 역할을 수행한다. SRSL의 최종복토층의로서의 적용성 파악을 위해서 실험실에서 연성벽체 투수시험기를 사용하여 투수 특성을 파악하였고 일축압축시험을 통하여 강도 및 강성 특성을 파악하였다. 또한 최종 복토층의 경우 환경적인 요인에 직접적으로 노출되어 있기 때문에 동결/융해 및 건조/습윤에 따른 SRSL의 투수 및 강도 특성 또한 알아보았다. 시험 결과, SRSL은 낮은 투수계수와 기준보다 높은 강도를 가진 매립장의 복토층 재료로 적합한 물질로 판단되며, 동결/융해 및 건조/습윤의 환경적인 영향에 대해서도 안정한 것으로 판명되었다.

• Corrosion Science and Technology
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• 제16권2호
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• pp.85-89
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• 2017

One of the most challenging issues in the oil and gas industry is corrosion assessment and management in subsea structures or equipment. At present, almost all steel pipelines are sensitive to corrosion in harsh working environments, particularly in salty water and sulphur ingress media. Nowadays, the most commonly practiced solution for a damaged steel pipe is to entirely remove the pipe, to remove only a localized damaged section and then replace it with a new one, or to cover it with a steel patch through welding, respectively. Numerous literatures have shown that fiber-reinforced polymer-based composites can be effectively used for steel pipe repairs. Considerable research has also been carried out on the repair of corroded and gouged pipes incorporated with hybrid natural fiber-reinforced composite wraps. Currently, further research in the field should focus on enhanced use of the lesser and highly explored hybrid-biocomposite material for the development in corrosion prevention. A hybrid-biocomposite material from renewable resource based derivatives is cost-effective, abundantly available, biodegradable, and an environmentally benign alternative for corrosion prevention. The aim of this article is to provide a comprehensive review and to bridge the gap by developing a new hybrid-biocomposite with superhydrophobic surfaces.

• 터널과지하공간
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• 제15권5호
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• pp.359-368
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• 2005

NATM 터널을 굴착하기에 토피가 너무 낮은 경우에는 보통 개착터널공법이 적용된다. 그러나 토피가 매우 낮거나 없는 계곡부에서 개착터널을 시공하기 위해서는 추가적인 두 곳의 갱구 형성과 복토가 이루어질 때까지 임시 사면에 대한 유지관리가 필요하다. 이런 경우에는 복토를 통해 토피를 확보한 후 터널을 굴착하는 방안이 유효하다. 이 연구는 터널 굴착이전에 소일시멘트로 복토한 후 굴착작업이 이루어진 대만고속철도 C240현장에 대한 사례 연구이다. 소일시멘트의 포틀랜드 시멘트 함유량은 $2\~4\%$이고, 1회 복토층의 두께는 $130\~250\;mm$ 범위가 되도록 시공하였다. 터널 굴착에 따른 소일시멘트 사면 및 터널내 최종 구조물인 콘크리트 라이닝에 대한 수치해석을 통해 안정성을 평가하였다.

• 한국지반공학회지:지반
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• 제13권4호
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• pp.5-12
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• 1997

현재, 하수 슬러지가 매립장에 주로 단순 매립되고 있는데, 이를 폐기물 매립장의 차수재 또는 복토재로 활용한다면 산업부산물의 재활용이라는 측면에서 큰 잇점이 있을 것이다. 이를 위하여 본 논문에서 하수 슬러지에 대한 다짐, 강도, 투수, 화학반응성 및 용출시험 등을 실시하여 매립장의 복토재 또는 차수재로서의 활용성을 검토하였다. 실험결과, 하수슬러지 혼합재는 벤토나이 트의 첨가량이 증가함에 따라 최대건조밀도는 증가하고 최적함수비는 감소하는 것으로 나타났다. 하수슬러지 혼합재의 강도는 벤토나이트의 첨가량이나 경과시간에 따라 증감효과가 크게 나타나지 않았다. 벤토나이트의 첨가량이 증가함에 따라 그리고 시간이 경과함에 따라 투수계수는 감소하였으며 투수계수가 1x10-7cm/sec가 되기 위한 벤토나이트의 첨가량은 약 40%정도로 나타났으며. 이는 차수재로서 하수슬러지를 활용한다면 벤토나이트 첨가량을 40%이상을 요구하며, 반면 복토재로 활용한다면 벤토나이트 첨가량이 20%이내임을 알 수있다. 하수슬러지 혼합재의 침출수와 반응성에 의한 투수특성 변화는 미약한 것으로 나타났다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.248-258
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• 2003

Finite element computations were carried out to study the indentation by rigid cone with half-angle of $70.3^{\circ}$ for 72 different combinations of elasto-plastic properties that cover the wide range of mechanical parameters of common engineering solid materials. The dimensional analysis and representative strain concept were used in the analysis. It was shown that for the same representative strain value, the loading curvature C can be formulated under two different forms, which are based on two alternative dimensionless functions. The present study's one is simpler than the other previously found by other authors using the similar approach. For a wide range of material's parameters, the hardness-modulus ratio should be a parabolic function of ${\sigma}E$, rather than a power law function earlier proposed.

• 한국환경과학회지
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• 제27권5호
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• pp.291-297
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• 2018

Vertical farming systems offer many advantages in urban spaces. They have also been proposed as an engineering solution to increase the productivity per unit area of cultivated land by extending crop production in the vertical dimension. However, soil water retention is a major constraint affecting the plant environment. This study analyzed the effects of growth environment of Tropaeolum majus and Fragaria spp., on the vertical farming system, by using four different types of cover material types including sphagnum moss (Control), a shading net (S.N.), multi-layered fabric (M.L.F.), and non-woven fabric (N.W.F.). The volumetric soil moisture contents and plant characteristics were investigated from May to September 2014. Plant materials were individually cultivated in hanging baskets measuring $30{\times}17{\times}17cm$, filled with a mixture of soil and perlite, and placed at 1.5m height. Each treatment was performed in quadruplicate and consisted of five plants, amounting to a total of 20 plants. The analysis indicated that different covers were associated with multiple functions and soil water retention improvements may have a positive impact on the vertical farming system. The difference in soil water retention increased in the following order: M.L.F. > Control > N.W.F. > S.N.. Furthermore, the differences in plant height and survival rate increased in the following order: M.L.F. > Control > N.W.F. > S.N. Therefore, M.L.F yielded satisfactory good response for the vertical farming system of cover materials. Our results clearly demonstrate that vertical spaces represent an attractive alternative to urban farming and suggest that further increases in yield may be achieved via different cover materials in vertical farming using hanging baskets.

• Structural Engineering and Mechanics
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• 제77권5호
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• pp.673-689
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• 2021

This paper addresses the efficiency of thermal insulation layers applied to protect structural elements strengthened by fiber-reinforced polymers (FRP) in the case of fire event. The paper presents numerical modeling and nonlinear analysis of reinforced concrete (RC) columns externally strengthened by FRP and protected by thermal insulation layers when subjected to elevated temperature specified by standard fire tests, in order to predict their residual capacity and fire endurance. The adopted numerical approach uses commercial software includes heat transfer, variation of thermal and mechanical properties of concrete, steel reinforcement, FRP and insulation material with elevated temperature. The numerical results show good agreement with published results of full-scale fire tests. A parametric study was conducted to investigate the influence of several variables on the structural response and residual capacity of insulated FRP-confined columns loaded by service loads when exposed to fire. The residual capacity of FRP-confined RC column was affected by concrete grade and insulation material and was shown to improve substantially by increasing the concrete cover and insulation layer thickness. By increasing the VG insulation layer thickness 15, 32, 44, 57 mm, the loss in column capacity after 5 hours of fire was 30%, 13%, 7% and 5%, respectively. The obtained results demonstrate the validity of the presented approach for estimation of fire endurance and residual strength, as an alternative for fire testing, and for design of fire protection layers for FRP-confined RC columns.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제12권3호
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• pp.27-34
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• 2006

Planning for the space of the Media Medical Department requires the details about the efficiency of the equipment and the operation in professional sector. For that, as designing, it is necessary to keep communicating with the experts on the technology and the officials from the company producing the equipment. One of the common concerns is not only how to insure enough room for the future extension and the upgrade of the equipment, as concerning the scale of the hospital, but the plan to cover movie cameras. As technology has been developed, despite the fact that machinery tend to be small, it can be possible to require continuously about the concerns of the scale because the camera taking body-picture tend to be much bigger and more complicated than before. Currently used diagnostic media techniques are divided by the method and the feature of the equipment such as Diagnostic X-ray, Ultrasound, CT, MRI, Angiography. The general and special photographing units which are used more than the other diagnostic parts, must be planned not for experiencing any inconvenience and unnecessary risks for the patients and must accept technical requirements. Also, it must be designed not to be seen as a clinic zone, as concerning the psychological stability of the patients. However, study of the general and special photographing units among the domestic general hospitals is insufficient. Also, as there is shortage of the material considering the development of the equipment, when planning, it's involving a lot of difficulties. Thus, this study has got a purpose on giving the basic material which is essential for further study, as suggesting the planning guidelines and the alternative plans for the general and special photographing units in a general hospital.

• 한국건설순환자원학회논문집
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• 제7권1호
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• pp.66-73
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• 2019

광산의 약 80%가 휴광 또는 폐광된 광산으로 대부분 적절한 환경처리시설 없이 방치되어 있다. 폐광산 주변 지역은 산성광산 배수와 침출수 유출 등의 문제가 발생되고 있으며, 이로 인한 지반 침하는 싱크홀 발생으로 안전사고를 유발시킬 수 있다. 본 연구에서는 기존 고로슬래그 미분말 기반 광산 차수재의 나노 실리카 및 실리카흄 대체율 변화에 따른 차수재의 기초 특성을 검토하기 위해 플로우, 압축강도, 흡수율, 기공특성, 수화특성을 실시하였다. 그 결과 나노실리카 및 실리카흄의 대체율이 증가할수록 나노실리카의 시험체는 실리카흄의 시험체보다 플로우, 압축강도가 증가하고 흡수율은 감소하였다. 기공특성의 경우 나노실리카 및 실리카흄 대체율이 증가할수록 기공량이 감소하는 것으로 나타났으며 특히 직경 10~1,000nm의 모세관 기공량이 감소하는 것으로 나타났다. 선 회절분석 및 SEM 측정은 Plain과 실리카흄 5% 대체 시험체와 비교할 경우 수화생성물의 피크 위치가 거의 동일하게 나타났다. 나노실리카 및 실리카흄의 사용은 광산 차수재의 수밀성 향상이 가능할 것으로 판단되며 경제성을 고려하여 적절히 사용한다면 광산 차수재의 재료로서 활용 가능할 것으로 판단된다.

• 무역상무연구
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• 제24권
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• pp.25-49
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• 2004

English contract law has traditionally taken the view that it is not the duty of the parties to a contract to give information voluntarily to each other. In English law, one of the principal distinctions between insurance contract law and general contract law is the existence of the duty of disclosure in insurance law. This article is, therefore, designed to analyse the scope or extent of the duty of disclosure and the remedy for breach of the duty in English marine insurance law. The main purpose of this article is also to seek the alternative remedy for the breach. The results of analysis are as following : First, the scope of the duty of disclosure is closely related to the test of materiality and the concept of a hypothetical prudent insurer. The assured is required to disclose only material circumstances subject to MIA 1906, s. 18(1). The test of materiality, which had caused a great deal of debate in English courts over 30 years, was finally settled by the House of Lords in Pan Atlantic and the House of Lords rejected the 'decisive influence' test and the 'increased risk' test, and the decision of the House of Lords is thought to accept the 'mere influence' test in subsequent case by the Court of Appeal. Secondly, an actual insurer is, in order to avoid contract, required to provide proof that he is induced to enter into the contract by reason of the non-disclosure of the assured. But this subjective test of actual inducement is somewhat meaningless in sense that English court takes the test of materiality as a starting point and assumes the presumption of inducement even in case of no clear proof on the inducement. Finally, MIA 1906, s. 18 provides expressly for the remedy of avoidance of the contract for breach of the duty of disclosure. This means rescission or retrospective avoidance of the entire contract, and the remedy is based upon a fairly crude 'all-or-nothing' approach. The remedy of rescission is too draconian from the point of view of the assured, because he can be deprived of all cover despite he is innocent perfectly. An inadvertent breach from an innocent mistake is as fatal as wilful concealment. What is, therefore, needed in English marine insurance law with respect to remedy for the breach is to introduce a more sophisticated or proportionate remedy ascertaining degrees of fault.