• Title/Summary/Keyword: 복합재 설계

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Current Status and Proposal of University Library Research Data Management Service: Focused on Science and Technology Specialized Universities (대학도서관 연구데이터 관리 서비스 현황 및 제안 - 과학기술특성화 대학을 중심으로 -)

  • Juseop Kim;Suntae Kim
    • Journal of the Korean Society for Library and Information Science
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    • v.57 no.3
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    • pp.279-301
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    • 2023
  • The data-driven research environment is rapidly changing. Accordingly, domestic university libraries are also preparing to establish and operate research data management services to support university researchers. This study was designed to propose a research data management service to support researchers in science and technology specialized university libraries. In order to propose the service, 11 universities specializing in science and technology were selected from overseas and domestic universities and their research data management services were analyzed. Key categories were derived from analysis results, research data management, electronic research notebooks, and RDM training. In particular, the 'research data management' category included DMP, data collection, data management, data preservation, data sharing and publishing, data reuse, infrastructure and tools. And it consists of RDM guides and policies. The results of this study will be helpful in introducing and operating research data management services in science and technology specialized university libraries.

Probabilistic Analysis and Design of the Spacing of Prefabricated Vertical Drains Considering Uncertainties in Geotechnical Property (지반 불확실성을 고려한 연직배수재 배치간격의 확률론적 해석과 결정)

  • Kim, Bang-Sig;Kim, Byung-Il
    • Journal of the Korean Geotechnical Society
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    • v.23 no.4
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    • pp.125-132
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    • 2007
  • The oedometer, radial CRS and Rowe cell tests, composite discharge capacity tests and smear effect tests are carried out to estimate the parameters for the reliability-based design of vertical drain method. Also the sensitivity analysis, the probabilistic and deterministic solutions of radial consolidation theory are presented. The result of probabilistic analysis was compared to that of deterministic analysis using the tested and estimated parameters. The results indicated that the drain spacing in the deterministic method is larger than that in the probabilistic method because the former does not consider the uncertainties in the geotechnical property. The divergence of two methods is dependent on the probability of achieving target degree of consolidation by a given time and the coefficient of variation (COV) of the coefficient of horizontal consolidation ($c_h$).

Practical discourse of civil democracy education in the elementary and the secondary school through the lense of competency education: based on human rights (역량교육을 통해 바라본 초·중등학교 민주시민교육의 실천적 담론: 인권을 중심으로)

  • Shin, Min-Hye
    • Journal of Digital Convergence
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    • v.20 no.5
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    • pp.813-817
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    • 2022
  • The purpose of the study was to suggest how and what human rights education goes with civil democracy education. Analysis of civil democracy education contents in the 2022 revised general education curriculum draft and that of the 2030 OECD Education project have been performed to find out what contents are necessarily included. Results are as follows: Firstly, human rights education needs to be adopted as an independent subject to be delivered with detailed and organized information. Secondly, actual experiences in diverse curricular and extracurricular activities need to be provided. Thirdly, a human rights-friendly atmosphere needs to be established to update teachers' perception and upgrade competency regarding human rights education. Lastly, it is expected that these activities facilitate adoption of human rights education curriculum into 2022 general education.

Development of a prefabricated rainwater infiltration storage block for reducing rainfall-runoff (우수유출저감을 위한 조립식 빗물 침투형 저류블록의 개발)

  • Koh, Byoung-Ryoun;Choi, Hee-Yong;Cha, Jung-Mann
    • Proceedings of the Korea Water Resources Association Conference
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    • 2020.06a
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    • pp.360-360
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    • 2020
  • 조립식 빗물침투형 저류블록은 우수유출 저감시설로, 황토 및 친환경 무기질 결합재를 이용하여 제작한 고강도 투수성 블록의 적층 및 요철에 의한 끼움식 조립에 의해 형성된 공간에 빗물을 저류하고, 저장된 빗물은 시간이 지남에 따라 지반으로 침투시키는 우수유출 저감용 빗물관리시설로, 집중강우 시 유출수가 발생하는 해당지역에 분산식으로 설치하여 국지적 호우 발생에 대처할 수 있으며, 지속적인 침투를 통한 지하수위 확보 및 가뭄현상의 저감은 물론, 미기후 조성과 건전한 물순환 구조 형성에 이바지하는 빗물관리기술이다. 본 기술은 집중형 대규모 빗물저류조의 적용상의 문제점과 단순저류의 한계성을 극복하고, 기존 침투시설의 낮은 침투능을 증대시키고자 저류기능과 침투기능을 동시에 확보하여 집중호우시 빠른 침투저류능을 향상시킨 조립식 빗물침투형 저류시설이다. 보다 구체적으로는 집중강우에 대한 방재적 측면과 함께 가뭄으로 발생하는 지하수위 저하 등에 친환경적으로 대응하기 위한 복합적인 빗물관리 기술로서, 빗물 유출저감과 함께 물순환 회복 및 저영향개발을 위한 각 지자체의 지침과도 부합될 수 있다. 또한, 콘크리트 제품의 환경적 문제점과 플라스틱 제품의 낮은 물성을 극복하였고, 시공 시에는 보다 현장상황에 맞게 가변적 형태로 적용이 가능한 단순조립 적층공법으로 공기단축에 탁월한 장점이 있으며, 유지관리 시에는 별도의 동력이 요구되지 않는 형태로 개발하였다. 조립식 빗물침투저류블록의 구조체를 이루는 단위 블록유닛은 투수성 소재로 제작되며, 상하부가 개방되어 있고 사각형의 내부에 힘을 받는 격벽과 전후벽이 상호 대응되는 요철로 형성되어 있으며, 단위블록 유닛 다수개가 수직수평으로 연속적으로 조립되어 규모의 제한, 형태의 제한이 없는 구조물 형성이 가능하다. 본 구조체의 저류공극율은 80%이상 확보 가능하며, 또한 블록자체의 투수율이 0.83mm/sec로서 순모래나 순자갈의 포화투수계수보다 투수율이 높아 침투저류 효율성이 높으며 시공 후 상부 토지는 자유롭게 활용 가능하다. 본 조립식 빗물 침투형 저류블록을 이용하여 저영향개발 계획, 우수유출 저감대책 수립, 빗물관리시설 계획시 기존의 시설들에 비하여 경제적, 효율적인 설계가 가능하다.

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A Study on the Structural Performance of Slab-column Joint at Flat Plate Structure Using ECC (고인성 시멘트 복합재를 활용한 플랫플레이트 구조의 슬래브-기둥 접합부 구조성능 연구)

  • Choi, Kwang-Ho;Park, Byung-Chun;Choi, Sung-Woo;Ryu, Deug-Hyun
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.209-216
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    • 2017
  • One of the important considerations in structural designing the flat plate system is ensuring the resistance to punching shear caused by axial loads and the ductile ability to follow horizontal deformation under earthquake. In this study, the ECC (Engineered Cementitious Composite) has been placed in the critical section zone of punching shear at slab-column joint to improve ductility and the advanced details of shear reinforced area nearby critical section zone has been developed using stud and steel fiber. The shear performance tests were performed on the specimens with parameters of fiber type mixed with ECC, stud and steel fiber set into the shear reinforced area in which the failure pattern, joint strength, displacement and strain of the specimen were compared and analyzed. The test results showed that the strength and ductility of specimens with ECC applied to joint were better than those of RC flat plate system. Also, the shear reinforcement effect of stud and the ductility improvement of steel fiber concrete were confirmed in the shear reinforcement area.

An Experimental Study on the Mechanical Properties of HPFRCCs Reinforced with the Micro and Macro Fibers (마이크로 및 매크로 섬유에 의해 보강된 고인성 시멘트 복합재료의 역학적 특성에 관한 실험적 연구)

  • Kim Moo-Han;Kim Jae-Hwan;Kim Yong-Ro;Kim Young-Duck
    • Journal of the Korea Concrete Institute
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    • v.17 no.2 s.86
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    • pp.263-271
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    • 2005
  • HPFRCC(High Performance Fiber Reinforced Cementitious Composite) is a class of FRCCs(Fiber Reinforced Cementitious Composites) that exhibit multiple cracking. Multiple cracking leads to improvement in properties such as ductility, toughness, fracture energy, strain hardening, strain capacity, and deformation capacity under tension, compression, and bending. These improved properties of HPFRCCs have triggered unique and versatile structural applications, including damage reduction, damage tolerance, energy absorption, crack distribution, deformation compatibility, and delamination resistance. These mechanical properties of HPFRCCs become different from the kinds and shapes of used fiber, and it is known that the effective size of fiber in macro crack is different from that in micro crack. This paper reports an experimental findings on the mechanical properties of HPFRCCs reinforced with the micro fiber(PP50, PVA100 and PVA200) and macro fiber(PVA660, SF500). Uniaxial compressive tests and three point bending tests are carried out in order to compare with the mechanical properties of HPFRCCs reinforced with micro fibers or hybrid fibers such as compressive strength, ultimate bending stress, toughness, deformation capacity and crack pattern under bending, etc.,

Numerical Study on Characteristics of Gas Leakage in an Underground Combined Cycle Power Plant (지하 복합발전 플랜트 내부의 가스 누출 특성에 대한 수치해석 연구)

  • Bang, Joo Won;Sung, Kun Hyuk;Ryou, Hong Sun;Lee, Seong Hyuk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.5
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    • pp.594-600
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    • 2016
  • The present study numerically investigated the gas leakage characteristics in a simplified underground combined cycle power plant. The effect of obstacles near a crack location on the gas concentration in the confined space was analyzed by using the lower flammable limit (LFL) of methane gas. When the jet flow was close to the vertical walls, the longitudinal leakage distance increased by about 60% (when an obstacles was present) compared to the case without any obstacle, because these obstacles prevented transverse flows. In addition, when an air filter was installed near to the trajectory of the gas flow, the longitudinal leakage distance was similar to the distance between the crack and obstacle, whereas the transverse leakage distance increased up to 8 times compared to the case without any obstacle. As the jet flow impacts on the obstacle and changes its direction, the gas flows recirculate. Therefore, it is necessary to consider the effect of the structure and facility locations on the trajectory of the jet flow to propose an accident prevention system in confined spaces.

Conductive Properties of Thermoplastic Carbon Fiber Reinforced Plastics Highly Filled with Carbon Fiber Fabrics and Conductive Carbon Fillers (탄소섬유 직물 및 전도성 탄소 필러가 고충진 된 열가소성 탄소섬유강화플라스틱의 전도 특성)

  • Kim, Seong Yun;Noh, Ye Ji;Jang, Ji-un;Choi, Seong Kyu
    • Composites Research
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    • v.34 no.5
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    • pp.290-295
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    • 2021
  • The application of lightweight structural composites to automobiles as a solution in line with global fuel economy regulations to curb global warming is recognized as a megatrend. This study was conducted to provide a technical approach that can respond to the issue of replacing parts that require conductive properties to maximize the application of thermoplastic carbon fiber reinforced plastics (CFRPs), which are advantageous in terms of repair, disposal and recycling. By utilizing the properties of the low-viscosity polymerizable oligomer matrix, it was possible to prepare a thermoplastic CFRP exhibiting excellent impregnation properties while uniformly mixing the conductive filler. Various carbon-based conductive fillers such as carbon black, carbon nanotubes, graphene nanoplatelets, graphite, and pitch-based carbon fibers were filled up to the maximum content, and electrical and thermal conductive properties of the fabricated composites were compared and studied. It was confirmed that the maximum incorporation of filler was the most important factor to control the conductive properties of the composites rather than the type or shape of the conductive carbon filler. Experimental results were observed in which it might be advantageous to apply a one-dimensional conductive carbon filler to improve electrical conductivity, whereas it might be advantageous to apply a two-dimensional conductive carbon filler to improve thermal conductivity. The results of this study can provide potential insight into the optimization of structural design for controlling the conductive properties of thermoplastic CFRPs.

An Investigation on the Long Term Durability of High-strength Shotcrete Using Field and Combined Deterioration Test (현장실험과 복합열화시험을 통한 고강도 숏크리트의 장기내구성 검토)

  • Ma, Sang-Joon;Choi, Jae-Seok;Ahn, Kyung-Chul;Kim, Sun-Myung;Kim, Dong-Min
    • Journal of the Korean Geotechnical Society
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    • v.22 no.10
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    • pp.77-91
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    • 2006
  • Domestic practices in shotcrete use have developed in many respects even now, but it still has issues about material, construction, quality standard and so on. In overseas, the construction using high strength shotcrete with $39.2{\sim}58.8 MPa$ of compressive strength is becoming common based on the shotcrete technology of high strength and durability. However, domestic shotcrete design strength is low at around 20.6 MPa of compressive strength and a long term durability is also insufficient. In this paper, field tests using high-quality additives and accelerators were performed to obtain the improvement of shotcrete strength and EFNARC standard was used to evaluate the field test results. In addition, deterioration test combined with the freezing-thawing and carbonation was also performed in order to investigate a long-term durability of high-strength shotcrete. As a result of the field test, the promotion ratio of early strength was $90{\sim}97%$ in case of using alkali-free accelerators. And the compressive strength of the shotcrete using Micro-silica fume was $45.2{\sim}55.8MPa$ and flexible strength was $5.01{\sim}6.66MPa$, so the promotion ratio of strength was $37{\sim}79%$ and $17{\sim}61%$ respectively. The promotion effect of strength by silica fine additives ratio of $7.5{\sim}10%$ for cement mass was much superior to the other cases. It was especially examined that using Micro-silica fume reduced deterioration due to mixed steel fiber and improved a long-term durability of shotcrete.

Shear Strength of Prestressed PC-CIP Composite Beams with Vertical Shear Reinforcement (전단 철근 보강된 프리스트레스 PC와 CIP 합성보의 전단강도)

  • Suh, Jung-Il;Park, Hong-Gun;Hong, Geon-Ho;Kang, Su-Min;Kim, Chul-Goo
    • Journal of the Korea Concrete Institute
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    • v.27 no.4
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    • pp.399-409
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    • 2015
  • Recently, the use of composite construction method using precast (PC) and cast-in-place (CIP) concrete is increased in modular construction. For PC members, pre-tensioning is used to improve efficiency of the structural performance. However, current design codes do not clearly define shear strength of prestressed PC-CIP composite members. In this study, 22 specimens were tested to evaluate shear strength of prestressed composite members with vertical shear reinforcement. The test variables were the area ratio of high-strength (60 MPa) to low-strength concrete (24 MPa), prestressing force of strands, shear span-to-depth ratio(a/d), and vertical shear reinforcement ratio. The test results showed the prestressing force did not completely restrain diagonal cracking of non-prestressed concrete in the web. Thus, the effect of prestress force was not insignificant in the effect for monolithic beams. The vertical shear strength and horizontal shear strength of the composite beams were compared with the strength predictions of KCI design method.