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Investigation of Aging Effect on Rheological Properties of Asphalt Binder in RAP Contained Mixture Design Process

  • Park, Kyung-Won;Rhee, Suk-Keun;Yoo, Ju-Yeol
    • 한국도로학회:학술대회논문집
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    • 2006.10a
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    • pp.105-114
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    • 2006
  • There are several methods determining an appropriate performance grade of virgin binder, which is re(erred as design binder, in RAP contained bituminous mixture design process. However, difficulties have been experienced in utilizing the methods in the field application in Korea, because SHRP binder test, the key tests to determine a design binder, requires well-trained personnel, high price equipment, and time consuming process. Thus, the study investigated the relationship among the binder aging level, RAP contents, and rheologica1 properties of binder. The study results provide mix designer with a simple method in selecting an appropriate grade of virgin binder.

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Vascular Endothelial Cadherin-mediated Cell-cell Adhesion Regulated by a Small GTPase, Rap1

  • Fukuhra, Shigetomo;Sakurai, Atsuko;Yamagishi, Akiko;Sako, Keisuke;Mochizuki, Naoki
    • BMB Reports
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    • v.39 no.2
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    • pp.132-139
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    • 2006
  • Vascular endothelial cadherin (VE-cadherin), which belongs to the classical cadherin family, is localized at adherens junctions exclusively in vascular endothelial cells. Biochemical and biomechanical cues regulate the VE-cadherin adhesive potential by triggering the intracellular signals. VE-cadherin-mediated cell adhesion is required for cell survival and endothelial cell deadhesion is required for vascular development. It is therefore crucial to understand how VE-cadherin-based cell adhesion is controlled. This review summarizes the inter-endothelial cell adhesions and introduces our recent advance in Rap1-regulated VE-cadherin adhesion. A further analysis of the VE-cadherin recycling system will aid the understanding of cell adhesion/deadhesion mechanisms mediated by VE-cadherin in response to extracellular stimuli during development and angiogenesis.

A modified tabu search for redundancy allocation problem of complex systems of ships

  • Kim, Jae-Hwan;Jang, Kil-Woong
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.2
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    • pp.225-232
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    • 2014
  • The traditional RAP (Redundancy Allocation Problem) of complex systems has considered only the redundancy of subsystem with homogeneous components. In this paper we extend it as a RAP of complex systems with heterogeneous components which is more flexible than the case of homogeneous components. We model this problem as a nonlinear integer programming problem, find its optimal solution by tabu search, and suggest an example of the efficient reliability design with heterogeneous components. In order to improve the quality of the solution of the tabu search, we suggest a modified tabu search to employ an adaptive procedure (1-opt or 2-opt exchange) to generate the efficient neighborhood solutions. Computational results show that our modified procedure obtains better solutions as the size of problem increases from 30 to 50, even though it requires rather more computing time. With some adjustment of the parameters of the proposed method, it can be applied to the optimal reliability designs of complex systems of ships.

Reliability Optimization for Multiple Multi-level Redundancy Allocation Problems using Genetic Algorithm (유전자 알고리듬을 활용한 혼합 다수준 리던던시 할당문제의 신뢰성 최적화)

  • Kim Ho-Gyun;Bae Chang-Ok;Yun Won-Yeong
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2006.05a
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    • pp.110-116
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    • 2006
  • 지금까지 대부분의 리던던시 할당문제(RAP: redundancy allocation problems) 관련 연구들에서는 최상위 수준에서의 시스템 리던던시보다는 최하위 수준인 부품의 리던던시를 고려하였다. 이는 최하위 수준에서의 리던던시가 최상위 수준의 리던던시보다 효과적이라고 알려진 일반적 원리 때문이었다. 최근 한 연구에서는 동일하지 않은 예비부품을 사용하여 리던던시를 실시하는 경우 직렬구조의 시스템에서도 일반적 원리와 다른 결과가 나타날 수 있음을 보이고, 시스템을 구성하는 모든 수준에서 리던던시가 가능한 다수준 리던던시 할당문제(MRAP: multi-level RAP)를 제시하였다. 그러나 MRAP는 모든 수준에서의 리던던시를 고려하지만 단지 한 수준을 선택하여 리던던시를 할 수 있다는 가정사항을 포함하고 있다. 본 연구에서는 MRAP의 이러한 가정사항을 완화하여 시스템을 구성하는 모든 수준에서 리던던시를 위한 수준을 복수로 선택 가능한 혼합 다수준 리던던시 할당문제(MMRAP: multiple MRAP)를 제시하고 모형화하며, 문제의 해법을 위한 유전자 알고리듬(GA: genetic algorithm)을 제시한다. 제시한 GA를 활용한 몇 가지 수치실험을 통해 모형이 기존의 RAP 경우보다 효과적임을 입증한다.

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Flow Regime Change Analysis using River Analysis Package (RAP를 이용한 금강유역 유황변화 분석)

  • Park, Sang-Young;Cheong, Tae-Sung;Kim, Jeong-Kon;Ko, Ick-Hwan
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.648-651
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    • 2007
  • 하천의 정상적인 기능을 회복시켜 하천 생태계 보전과 환경적으로 안정된 하천 조성이 이루어지도록 하기 위해서는 하천을 보다 자연스럽고 지속적으로 관리하기 위한 효율적인 환경유량의 관리가 필요하다. 본 연구의 목적은 수리구조물에 의한 하천유황 및 하천환경의 변화를 분석하는 기법을 제안하는데 있다. 이를 위하여 먼저, KModSim모델을 이용하여 금강수계에 위치한 대청댐과 용담댐의 운영 전후 가정조건하에서 1984년부터 2006년까지 22년간의 유량자료를 수통지점과 공주지점에 대하여 생산한 후, 환경유량 설정 도구로서 호주 eWater CRC에서 개발한 RAP(River Analysis Package)을 이용하여 금강유역의 유황변화를 통계적으로 분석하였다. 본 연구결과는 향후 수질, 서식처 등 하천환경 변화를 포함하여 하천의 건강성 평가를 위한 기초자료로 사용될 것이다.

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3D Rebar Placing and Drawing System (3차원 배근 설계 및 배근시공도 작성 시스템)

  • Lee, Byeong-Kwun;Kim, Chee-Kyeong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2010.04a
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    • pp.529-532
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    • 2010
  • 본 연구에서는 철근가격 급등과 배근시공도 작성 인력 부족에 대비하여 SDM# 제품군을 사용하여 이음/정착을 고려한 3차원 철근 배근 자동화 기술(RAP)로 철근 배근 자동생성 및 배근시공도 작성 시스템을 개발하였다. 최근 철근가격 급등으로 인한 공사원가상승/인건비 상승/배근시공도 작성 인력 부족 등의 기존현황의 문제점 등을 SDM# 제품군의 철근 배근 자동화 기술(RAP)을 이용하여 자동 철근배근/배근시공도 작성/정밀 골조물량 산출/인력절감/시공 정밀도 향상/골조 공사비 절감 등의 효과와 기존의 현장가공으로 인한 철근 손실률 8%를 공장가공을 적용함으로써 3% 수준으로 낮출 수 있어 5% 내외의 절감효과를 얻을 수 있다. 철근현장가공에서 공장가공 전환으로 골조물량 절감을 기대할 수 있고, 이음/정착/응력분포가 고려된 3차원 철근 배근 자동화 기술(RAP)을 이용하여 자동배근 알고리즘에 의한 배근시공도/가공도 작성 효율을 높이고, 기술 자립을 통해 건설시공 분야의 기술력 향상을 기대할 수 있다.

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On the Print Through of the paper prepared from red algae pulp (홍조류 종이의 인쇄 뒤비침에 관한 연구)

  • Lim, Soo-Man;Youn, Jong-Tae;Lee, Young-Sea;Seo, Yung-Bum
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2008.04a
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    • pp.129-134
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    • 2008
  • Properties of newly developed paper from Red Algae Pulp (RAP) were examined. The paper samples were prepared by mixing RAP fiber with wood fibers, HwBKP and SwBKP, to form a paper with $60g/m^2$ in weight. It was prepared in three to four different levels of refining degree and pressure so that it can reveal different bulk level in order to clearly compare the opacity at equivalent bulk for each furnish compositions. Printability of RAP fiber revealed superior effect on print through repression and initial ink absorption. Those properties are expected to improve further if printability improvement effect due to smoothness improvement is added.

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Isomeric Composition of Hydroperoxides Formed by Autoxidation of Adlay Lipid and Triglyceride (율무 지방빌의 자동산화에 의해서 형성된 Hydroperoxides 이성체 조성)

  • 한지숙;이숙희;최홍식
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.19 no.3
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    • pp.229-233
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    • 1990
  • The compositions of hydroperoxy fatty acid components of lipid in raw adlay powder(RAP) and processed adlay powder(PAP) stored at 35$^{\circ}C$ and PAP lipid and triglyceride(TG) autoxi야-zed 35$^{\circ}C$ were studied. During autoxidation the time taken to reach 100 of peroxide and 13-hydroperoxide isomers were the major hydroperoxy fatty acids found in oxidized adlay lipid. Lower levels of 8-. 10-, 11-, 12- and 16-hydroperoxide isomer were also observed. The composi-tions of hydroperoxy fatty acid componets obtained from sutoxidized RAP lipid and TG were similar to those of hydroperoxy fatty acid components is lipid extracted from stored RAP and PAP.

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A Study on the Performance of Recycled Asphalt Pavement using Hot Recycling Plant (재생 아스팔트 포장의 공용성능 연구)

  • Kim, In-Soo;Suh, Young-Chan
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.2
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    • pp.112-118
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    • 2011
  • The recycled asphalt concrete has gotten increasing attention due to the environmental issues. The volume of reclaimed asphalt has increased significantly for last few years because of city remodeling, pavement maintenance, utility excavation, and road widening. Considering the value of reclaimed asphalt, it is rather used for the recycled asphalt concrete than it is used for fill and cover up material instead of soil. This research will be a supplements incomplete issues from existing research results and suggests the quality control guideline for recycled asphalt concrete and upcoming laws. As the first step of research, the trial construction of RAP(Recycled Asphalt Pavement) performed in expressway construction sites. These trial construction sites have been checked every years. And another construction sites studied and selected for more deeper performance check of RAP. For this checks, we used automatic pavement survey equipment and computerized analysis tools. Also, DSR(Dynamic Shear Rheometer) was used for the fatigue life calculation of binder blends(RAP and virgin binder). As a consequence of this research, the application of recycled asphalt provides good enough quality for highway construction. The preceeding literatures reviewed shows that the asphalt rejuvenator are used in many countries but that type of chemical agent are not used in Korea. By using the data of trial construction and mix design in Chongwon-Sangju construction lane, the surface and base courses consisted with the 10% and 30% rap mix asphalt section maintains good performance for up to 7 years. Through the performance check and laboratory tests(DSR), the quality control and mixture's low temperature prevention are the important factor and chemical agent necessary for increasing the fatigue life of RAP binder.

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Determination of Dynamic Modulus of cold In-place Recycling Mixtures with Foamed Asphalt (폼드아스팔트를 이용한 현장 상온 재생 아스팔트 혼합물의 동탄성계수 결정)

  • Kim, Yong-Joo Thomas;Lee, Ho-Sin David
    • International Journal of Highway Engineering
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    • v.11 no.1
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    • pp.1-12
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    • 2009
  • A new mix design procedure for cold in-place recycling using foamed asphalt (CIR-foam) has been developed for Iowa Department of Transportation. Some strengths and weaknesses of the new mix design parameters were considered and modified to improve the laboratory test procedure. Based on the critical mixture parameters identified, a new mix design procedure was developed and validated to establish the properties of the CIR-foam mixtures. As part of the validation effort to evaluate a new CIR-foam mix design procedure, dynamic moduli of CIR-foam mixtures made of seven different reclaimed asphalt pavement (RAP) materials collected throughout the state of Iowa were measured and their master curves were constructed. The main objectives of this study are to provide: 1) standardized testing procedure for measuring the dynamic modulus of CIR-foam mixtures using new simple performance testing (SPT) equipment; 2) analysis procedure for constructing the master curves for a wide range of RAP materials; and 3) impacts of RAP material characteristics on the dynamic modulus. Dynamic moduli were measured at three different temperatures and six different loading frequencies and they were consistent among different RAP sources. Master curves were then constructed for the CIR-foam mixtures using seven different RAP materials. Based upon the observation of the constructed master curves, dynamic moduli of CIR-foam mixtures were less sensitive to the loading frequencies than HMA mixtures. It can be concluded that at the low temperature, the dynamic modulus is affected by the amount of fines in the RAP materials whereas, at the high temperature, the dynamic modulus is influenced by the residual binder characteristics.

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