• Title/Summary/Keyword: wrapping system

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Full-Scale Shaker Testing of Non-Ductile RC Frame Structure Retrofitted Using High-Strength Near Surface Mounted Rebars and Carbon FRP Sheets (고강도 표면매립용철근과 탄소섬유시트로 보강된 비연성 철근콘크리트 골조의 실물 진동기 실험)

  • Shin, Jiuk;Jeon, Jong-Su;Wright, Timothy R.
    • Journal of the Earthquake Engineering Society of Korea
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    • v.23 no.1
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    • pp.43-54
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    • 2019
  • Existing reinforced concrete frame buildings designed for only gravity loads have been seismically vulnerable due to their inadequate column detailing. The seismic vulnerabilities can be mitigated by the application of a column retrofit technique, which combines high-strength near surface mounted bars with a fiber reinforced polymer wrapping system. This study presents the full-scale shaker testing of a non-ductile frame structure retrofitted using the combined retrofit system. The full-scale dynamic testing was performed to measure realistic dynamic responses and to investigate the effectiveness of the retrofit system through the comparison of the measured responses between as-built and retrofitted test frames. Experimental results demonstrated that the retrofit system reduced the dynamic responses without any significant damage on the columns because it improved flexural, shear and lap-splice resisting capacities. In addition, the retrofit system contributed to changing a damage mechanism from a soft-story mechanism (column-sidesway mechanism) to a mixed-damage mechanism, which was commonly found in reinforced concrete buildings with strong-column weak-beam system.

Experimental behavior of eccentrically loaded RC slender columns strengthened using GFRP wrapping

  • Elwan, S.K.;Omar, M.A.
    • Steel and Composite Structures
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    • v.17 no.3
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    • pp.271-285
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    • 2014
  • This paper aims to examine the behavior of slender reinforced concrete columns confined with external glass fiber reinforced polymers (GFRP) sheets under eccentric loads. The experimental work conducted in this paper is an extension to previous work by the author concerning the behavior of eccentrically loaded short columns strengthened with GFRP wrapping. In this study, nine reinforced concrete columns divided into three groups were casted and tested. Three eccentricity ratios corresponding to e/t = 0, 0.10, and 0.50 in one direction of the column were tested in each group. The first group was the control one without confinement with slenderness ratio equal 20. The second group was the same as the first group but fully wrapped with one layer of GFRP laminates. The third group was also fully wrapped with one layer of GFRP laminates but having slenderness ratio equal 15. The experimental results of another two groups from the previous work were used in this study to investigate the difference between short and slender columns. The first was control one with slenderness ratio equal 10 and the second was fully wrapped and having the same slenderness ratio. All specimens were loaded until failure. The ultimate load, axial deformation, strain in steel bars, and failure mechanisms of each specimen were generated and analyzed. The results show that GFRP laminates confining system is less effective with slender columns compared with short one, but this solution is still applied and it can be efficiently utilized especially for slender columns with low eccentric ratio.

A Study on the Analysis Method to API Wrapping that Difficult to Normalize in the Latest Version of Themida (최신 버전의 Themida가 보이는 정규화가 어려운 API 난독화 분석방안 연구)

  • Lee, Jae-hwi;Lee, Byung-hee;Cho, Sang-hyun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.29 no.6
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    • pp.1375-1382
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    • 2019
  • The latest version of commercial protector, Themida, has been updated, it is impossible to apply a normalized unpacking mechanism from previous studies by disable the use of a virtual memory allocation that provides initial data to be tracked. In addition, compared to the previous version, which had many values that determined during execution and easy to track dynamically, it is difficult to track dynamically due to values determined at the time of applying the protector. We will look at how the latest version of Themida make it difficult to normalize the API wrapping process by adopted techniques and examine the possibilities of applying the unpacking techniques to further develop an automated unpacking system.

Application of a PERT-Type System on Work Management in Home-Delivered Meals Service Program for Elderly (가정배달 노인급식서비스 작업공정관리 모형개발을 위한 PERT-Type System의 적용)

  • 양일선;채인숙;유일근
    • Journal of Nutrition and Health
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    • v.34 no.6
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    • pp.701-714
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    • 2001
  • The purpose of this study was to apply a PERT-type system, a combination of the project evaluation and review technique(PERT) and critical path method(CPM) on the employees' work time management of flood preparation, assembly, transportation and cleaning in home-delivered meals program for elderly The resources allotment heuristic program was developed by considering the number of employees and cooking utilities, being limited resources of home- delivered meals program. This program could assign the employees to perform the works included in flood preparation, assembly, transportation ind cleaning. Critical path and activities ware identified by PERT-type system on the basic of work time investigation in five senior centers. Work sheets were invented to perform the work by the shortest path with flexible employees'maximum flow As a result of the work time investigation, the most prevalent activities were ones of preparation in center C and E. Besides, the preparation(over fifty percent) was the most proportion among flood preparation, assembly, transportation and cleaning in center C and E. Critical path and activities of 'C'center were cucumber in sauce preparation path and assembly, wrapping in assembly path and case delivery in transportation path. Critical path and activities of 'E'center were Pan-fried Potato Preparation Path and assembly, case covering, wrapping in assembly Path. The work sheet invented by the heuristic program and PERT-type system reduced the work completion time and man hours in both centers.

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Development of a Tractor Attached Round Bale Wrapper(II) - Manufacturing of proto-type bale wrapper and its performance test (트랙터 견인형 원형 베일 랩퍼의 개발(II) - 시작기의 제작 및 성능 평가 -)

  • Kim, H. J,;Park, K. K.;Myung, B. S.;Choi, J. S.;Kim, T. W.;Jang, C.;Hong, D. H.
    • Journal of Biosystems Engineering
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    • v.27 no.3
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    • pp.195-202
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    • 2002
  • In order to make a winter cereal wrap silage, a tractor attached round bale wrapper was developed locally. Its specific structure and various functions were reported in the last submitted paper. In this study a control system of bale wrapper combining with the actuators of various processes was developed to make round bale wrapper compatible in the field. Also. its performance was tested by making the rye round bale. The results can be summarized as fellow. 1. The field capacity of round bale wrapping was investigated around 0.5 ha/hr, and the operating time of bale wrapper was about 3 min for each 500kg round bale 2. Plastic film which has maximum elongation rate of 796% was stretched to 150∼170% of original length and was lessened to 80∼90% of original width. 3. In the quality test of bale produced by developed bale wrapper, there was no significant changes of moisture contents if it was wrapped more than 4 layers of 25 ㎛-plastic film. 4. Also. temperature of the wrapped bale was about 33$\^{C}$ in the beginning of fermentation and was stabled to 26∼29$\^{C}$ during one month or more storage. Therefore, wrapping performance of the developed bale wrapper was properly.

Effect of BFRP Wrapping on Seismic Behavior of Rectangular RC Columns (BFRP 보강이 직사각형 단면 철근콘크리트 기둥의 지진거동에 미치는 영향)

  • Lee, Hyerin;Cho, Junghyun;Lee, Seung-Geon;Lee, Su-Hyung;Hong, Kee-Jeung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.6
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    • pp.153-160
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    • 2020
  • Columns are one of the most critical parts of a structural system subjected to earthquake excitations. In this regard, extensive experimental studies have been conducted to evaluate the effect of fiber reinforced polymer (FRP) wrapping on the seismic performance of reinforced concrete (RC) columns. Among them, many studies focused on the behavior of circular or square RC columns strengthened with CFRP or GFRP sheets. Since the cross-sectional shape affects confinement by FRP wrapping, its strengthening effect and final damage pattern may differ with shapes. In this study, a series of cyclic tests was conducted to investigate the seismic behavior of rectangular reinforced concrete columns strengthened with basalt-based fiber reinforced polymer (BFRP) sheets and composite fiber panels. The result shows that the effect of strengthening is not significant, and it implies a little increase of confinement by BFRP sheets and composite fiber panels, which is considered partly due to the cross-sectional shape of the columns.

Development of Automatic Wrapping System for Several with a Wrapping Foil (WRAP FOIL을 이용하여 다수포장이 가능한 오이 자동포장기 개발)

  • Lee, Dae-Won;Kim, Hyun-Tae;Min, Byung-Ro;Kim, Woong;Sung, Si-Hong
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1998.10a
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    • pp.36-40
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    • 1998
  • 대부분의 과채류가 그러하듯이 신선도는 상품가치 판단기준의 가장 중요한 척도중에 하나이다. 현장에서 생산된 상태로 소비자에게 가장 빠른 유통경로를 통해서 공급되는 것이 가장 바람직하지만, 때로는 그렇지 못하는 경우도 생긴다. 따라서 가능하면 수확, 운반, 저장시에 신선도를 오래 유지할 수 있도록 만드는 것이 여러 가지 측면에서 유리하다. (중략)

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