• Title/Summary/Keyword: Replacement method

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The Characteristics of the Improvement of the Clayey soil in the Composite Ground with Sand Compaction Pile(SCP) using Unit-cell test (단위셀 시험을 이용한 SCP 공법 적용지반 점성토의 개량특성)

  • Lee, Dong-Hyun;Shin, Hyun-Young;Han, Sang-Jae;Kim, Soo-Sam
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.982-989
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    • 2005
  • In this study, a series of laboratory tests based on 'Unit-cell concept' are performed to investigate improvement characteristics of clay ground in sand compaction pile method. Settlement reduction characteristics of composite ground and improvement characteristics of clay part could be qualified. In these procedure, the new strain-compression index($C_{\epsilon}$) of composite ground are adopted to show compressibility of composite ground according to the area replacement ratio, which is similar to the compression index($C_c$) in pure clay ground. Also, using normalization of reduction of water content in composite ground to the initial water content, improvement characteristics of clay part are investigated.

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Optimal Mixture Proportion for High Performance Concrete Incorporating Ground Granulated Blast furnace Slag

  • Choi Jae-Jin;Kim Eun-Kyum;Yoo Jung-Hoon
    • Journal of the Korea Concrete Institute
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    • v.17 no.3 s.87
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    • pp.473-480
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    • 2005
  • In this study, a mix design for self compacting concrete was based on Okamura's method and concrete incorporated just a ground granulated blast furnace slag. Replacement ratio of slag is in the range of $20-80\%$ of cement matrix by volume. For the optimal self compactability in mixture incorporating ground granulated blast furnace slag, the paste and mortar tests were first completed. Then the slump flow, elapsed time of 500mm slump flow, V funnel time and filling height by U type box were conducted in concrete. The volume of coarse aggregate in self compacting concrete was in the range of $50-60\%$ to the solid volume percentage of coarse aggregate. Finally, the compressive and splitting tensile strengths were determined in the hardened self compacting concrete incorporating ground granulated blast furnace slag. From the test results, it is desirable for self compacting concrete that the replacement of ground granulated blast furnace slag is in the range of $40-60\%$ of cement matrix by volume and the volume of coarse aggregate to the solid volume percentage of coarse aggregate with a limit of $55\%$.

Therapeutic Use of Stem Cell Transplantation for Cell Replacement or Cytoprotective Effect of Microvesicle Released from Mesenchymal Stem Cell

  • Choi, Moonhwan;Ban, Taehyun;Rhim, Taiyoun
    • Molecules and Cells
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    • v.37 no.2
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    • pp.133-139
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    • 2014
  • Idiopathic pulmonary fibrosis (IPF) is the most common and severe type of idiopathic interstitial pneumonias (IIP), and which is currently no method was developed to restore normal structure and function. There are several reports on therapeutic effects of adult stem cell transplantations in animal models of pulmonary fibrosis. However, little is known about how mesenchymal stem cell (MSC) can repair the IPF. In this study, we try to provide the evidence to show that transplanted mesenchymal stem cells directly replace fibrosis with normal lung cells using IPF model mice. As results, transplanted MSC successfully integrated and differentiated into type II lung cell which express surfactant protein. In the other hand, we examine the therapeutic effects of microvesicle treatment, which were released from mesenchymal stem cells. Though the therapeutic effects of MV treatment is less than that of MSC treatment, MV treat-ment meaningfully reduced the symptom of IPF, such as collagen deposition and inflammation. These data suggest that stem cell transplantation may be an effective strategy for the treatment of pulmonary fibrosis via replacement and cytoprotective effect of microvesicle released from MSCs.

Study of Failure Mode and Static Behavio of Lightweight FRP Bridge Deck System (복합재료 교량 시스템의 정적거동 분석 및 파괴모드에 관한 연구)

  • Jung Woo-Young;Lee Hyung-Kil;An Byoung-Yun;Baek Sang-Hoon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.922-927
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    • 2006
  • There is a concern with worldwide deterioration of highway bridges, particularly reinforced concrete. The advantages of fibre reinforced plastic(FRP) composites over conventional materials motivate their use in highway bridges for replacement of structures. Recently, an FRP deck has been installed on a state highway, located in New York State, as an experimental project. In this paper, a systematic approach for analysis of this FRP deck bridge is presented. Multi-step linear numerical analyses have been performed using the finite element method to study the structural behavior and the possible failure mechanism of the FRP deck-superstructure system Deck's self-weight and ply orientations at the interface between steel girders and FRP deck are considered in this study. From this research, the results of the numerical analyses were corroborated with field test results. Analytical results reveal several potential failure mechanism for the FRP deck and truss bridge system The results presented in this study may be used to propose engineering design guideline for new and replacement FRP bridge deck structure.

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Resistance to Corrosion of Reinforcement of High Volume Fly Ash Concrete

  • Kwon, S.O.;Bae, S.H.;Lee, H.J.;Lee, K.M.;Jung, S.H.
    • Corrosion Science and Technology
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    • v.13 no.6
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    • pp.209-213
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    • 2014
  • Due to the increasing of interest about the eco-friendly concrete, it is increased to use concretes containing by-products of industry such as fly ash(FA), ground granulated blast furnace slag(GGBFS), silica fume(SF), and etc. Especially, these are well known for improving the resistances to reinforcement corrosion in concrete and decreasing chloride ion penetration. The purpose of this experimental research is to evaluate the resistance against corrosion of reinforcement of high volume fly ash(HVFA) concrete which is replaced with high volume fly ash for cement volume. For this purpose, the concrete test specimens were made for various strength level and replacement ratio of FA, and then the compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91, and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that the compressive strength of HVFA concrete was decreased with increasing replacement ratio of FA but long-term resistances against reinforcement corrosion and chloride ion penetration of that were increased.

Clinical Study of the Effect of Aprotinin for Hemostasis in Open Heart Surgery (개심술시 Aprotinin의 지혈효과에 관한 임상적 고찰)

  • 정성운;김종원
    • Journal of Chest Surgery
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    • v.32 no.4
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    • pp.364-367
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    • 1999
  • Background: The efficacy of the hemostasis of prophylactic aprotinin after cardiac valve replacement was evaluated from January 1994 to December 1996 at Pusan National University Hospital. Material and Method: In a randomized study, 20 patients received aprotinin(2${\times}$106 KIU as a loading dose for 30 minutes after anesthesia, 1${\times}$106 KIU for priming and 5${\times}$105 KIU/hr as a maintenance dose from the completion of loading dose till skin closure) and another 20 untreated patients served as controls. Result: Aprotinin produced a significant reduction in postoperative blood loss compared with controls and significantly decreased total exposure to allogenic blood products compared with the control group(p<0.05). Conclusion: We conclude that aprotinin effectively reduces postoperative blood loss and trasfusion in patient undergoing cardiac valve replacement.

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Use of a Valved-Conduit for Exclusion of the Infected Portion in the Prosthetic Pulmonary Valve Endocarditis

  • Jung, Joonho;Hong, You Sun;Lee, Cheol Joo;Lim, Sang-Hyun;Choi, Ho;Park, Soo-Jin
    • Journal of Chest Surgery
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    • v.46 no.3
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    • pp.208-211
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    • 2013
  • A 51-year-old male was admitted to the hospital with complaints of fever and hemoptysis. After evaluation of the fever focus, he was diagnosed with pulmonary valve infective endocarditis. Thus pulmonary valve replacement and antibiotics therapy were performed and discharged. He was brought to the emergency unit presenting with a high fever (> $39^{\circ}C$) and general weakness 6 months after the initial operation. The echocardiography revealed prosthetic pulmonary valve endocarditis. Therefore, redo-pulmonary valve replacement using valved conduit was performed in the Rastelli fashion because of the risk of pulmonary arterial wall injury and recurrent endocarditis from the remnant inflammatory tissue. We report here on the successful surgical treatment of prosthetic pulmonary valve endocarditis with an alternative surgical method.

Biomechanical characteristics of the distal filling effects in cementless femoral stem (무시멘트형 대퇴스템에서 원위부 압박 정도에 따른 생체역학적 특성)

  • Park, Sang-eok;Park, Jae-Won;Chae, Soo-Won
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.387-392
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    • 2000
  • In cementless total hip replacement(THR), an initial stability of the femoral component is important to long term fixation of femoral stem. The initial stability has close relationship with the relative displacement of prosthesis and spongy bone at the proximal of femur. After implantation of the prosthesis. the surrounding bone is partially shielded from load carrying and starts to resort. Stress shielding is the cause of the loss of proximal bone. Assessing stress distribution of femur is important to predict stress shielding. The initial stability and the stress shielding were investigated for two loading conditions approximating a single leg stance and a stair climbing. Three types of stems were studied by the finite element method to analyze the biomechanical effects of distal filling of cementless femoral stems, Three types of stems employed are a distal filling stem, a distal flexible stem, and a distal tapered stem.

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Food and Nutrition Students' Evaluation for Home Meal Replacement Quality Using Importance-Performance Analysis

  • Park, Kyung-Sook;Kim, Jong-Baek;Yang, Hoe-Chang
    • Journal of Distribution Science
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    • v.13 no.7
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    • pp.19-24
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    • 2015
  • Purpose - This study attempts to identify the attributes of home meal replacements (HMR) from the perspective of consumers as well as suggest some directions for HMR. Research Design, Data, and Methodology - For the research, food and nutrition professors were interviewed and surveys were completed using the revised Delphi method to identify attributes of HMR. Subsequently, a total of 140 food and nutrition students already aware of HMR were asked to rate the attributes in terms of importance and satisfaction. In addition, Importance-Performance Analysis (IPA) was conducted. Results - According to the analysis results, a total of seven key factors were deduced from the attributes ratings and the Kaiser-Meyer-Olkin (KMO) criteria, which is used to verify the appropriateness of the selection of the variables. Conclusion - The findings could be helpful in the future as reference data for HMR producers and distributors to assist in the diagnosis of the status of HMR. Additionally, the data may point to some areas that need greater attention in terms of production as well as marketing.

Results with Total Replacement of the Ascending Aorta and Reimplantation of the Coronary Arteries (대동맥관 폐쇄부전을 동반한 상행대동맥의 외과적 치료)

  • Ahn, Hyuk;Rho, Joon-Ryang
    • Journal of Chest Surgery
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    • v.24 no.4
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    • pp.352-356
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    • 1991
  • From April, 1981, to April, 1990, 20 male and 7 female patients ranging in age from 17 to 63, were operated on for aortic insufficiency with an aneurysm of the ascending aorta. Ten patients were in New York Heart Association functional class II, 7 in class III, and ten in class IV. The surgical treatment in all cases consisted of total replacement of the ascending aorta with composite graft containing a prosthetic aortic valve and reimplantation of the coronary arteries by an intermediate tube graft. In 15 patients an uncomplicated annulo-aortic ectasia existed, and in 12 an aortic dissection; three of the latter group were operated during the acute phase. 17 patients showed typical Marfan syndrome, and 3 patients showed severe ascending aortic aneurysm secondary to the aortic valve disease. The overall operative mortality was 7%[2 deaths]. Those 2 deaths occurred following emergency operation due to associated aortic dissection, but no death during elective operation. All survivors have been followed-up during a period ranging 1 to 108 month[average 34 months]. There was no late mortality. Among the survivors, clinical improvement is readily apparent[2,3 in class I, 2 in class II ]. In conclusion, the treatment of aortic insufficiency associated with an aneurysm of the ascending aorta by insertion of a composite graft and reimplantation of the coronary arteries through an intermediate Dacron tube is a reliable method with low mortality and excellent results.

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