• 제목/요약/키워드: replace cycle

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컨베이어 라인 변경시 U - 라인 설계의 효율적 방안 - K전자 사례를 중심으로 - (The Design of the U-Shaped Assembly Line to Replace Conveyor Systems)

  • 박승헌
    • 산업공학
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    • 제16권2호
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    • pp.240-247
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    • 2003
  • Generally, the assembly system relied on conveyor lines is efficient for mass production. But it is not efficient when the product types are often varying and their lot sizes are small. Especially, it is much inefficient for the assembly lines for the electronic products whose types are varying very often. This paper suggests the design of U-shaped assembly lines to replace the existing conveyor systems. The assembly line for the mini-cassette production is dealt with as a case study. The proposed procedure was successfully applied for the design of U-shaped lines. The developed method resulted in the improvement of the productivity such as the decrease of the man power and the cycle time, and the increase of the line utility.

공동주택 자재표준화를 위한 조립기준면 설계기준에 관한 연구 (A Study on the Design Guideline based Reference Plane for Standardization in Material of the Multi-family housing)

  • 박근수;임석호;지장훈
    • 한국주거학회:학술대회논문집
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    • 한국주거학회 2008년도 춘계학술발표대회 논문집
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    • pp.241-244
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    • 2008
  • This study focused on the checking of design guideline using concept of reference plane as a promoting tool in order to apply to practical affair in relation to material standardization in housing build. For this purpose, we above all defined the role of reference plane. After establishing structural type can correspond to planning module of building components and coordination condition, we did exemplicated the sub-detail of building components which be to detach according to design method using the concept of reference plane that be complexed with spacial territory and replace cycle of building component or material.

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자동차휠용 A356 알루미늄 합금의 주조조직이 피로특성에 미치는 영향 (Effect of Cast Microstructure on Fatigue Behaviors of A356 Aluminum Alloy for Automotive Wheel)

  • 송전영;박중철;안용식
    • 한국주조공학회지
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    • 제30권1호
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    • pp.46-51
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    • 2010
  • Recently, automotive industry is attempting to replace steels for automotive parts with light-weight alloys such as aluminum alloy, because of the growing environmental regulations governing exhaust gas and the engine effectiveness of a vehicle. The low cycle fatigue (LCF) and high cycle fatigue (HCF) properties as well as the microstructure and tensile property were investigated on the low pressure cast A356 aluminum alloy wheel, which was followed by T6 heat treatment. The cast microstructure of the alloy influenced significantly on the low cycle and high cycle fatigue behaviors. The rim part of cast aluminum alloy wheel showed higher low cycle and high cycle fatigue strength compared with the spoke part, which should be caused by higher cooling rate of rim part. The spoke part of the wheel showed coarser dendrite arm spacing (DAS) and wide eutectic zone in the microstructure, which resulted in the partial brittle fracture and lower fatigue life time.

실사용조건을 모사한 전차선 굽힘피로 특성평가 시스템개발 (Development of Bending Fatigue Test System for Trolley Line Simulating Real Conditions)

  • 강민성;안상수;구재민;석창성;이기원;조용현
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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    • pp.3059-3064
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    • 2011
  • A Trolley line is a very important equipment among electric railway equipments since it contacts directly with pantograph and supplies electricity on the electromotive. Such it was thought that a trolley line need not to consider fatigue since the replace cycle by wear is shorter than the replace cycle by fatigue breakage. But, the bending fatigue breakage accidents occurred several times at the Shinkansen trolley line in East Japan Railway Company. Therefore, in case of a new developed trolley line, the evaluation for bending fatigue life became more important, But, since there are not an authorized fatigue test method and a testing device for the trolley line, the quantitative evaluation is difficult. In this study, we analyzed the load and environment condition of trolley line used in the actual spot and the developed testing device that can evaluate bending fatigue properties of the trolley line as simulating the real condition. The bending fatigue test of the trolley line was achieved using the developed testing device and estimated the fatigue life of trolley line and also, established the fatigue test process.

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모터 회전 각도를 활용한 타이어 마모도 확인 기법 (Detection method for a tire wear using a motor rotation angle)

  • 서의성;장종욱
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2017년도 춘계학술대회
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    • pp.252-254
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    • 2017
  • 자동차 타이어는 차량을 운행하는데 있어 중요한 요소 중 하나이다. 타이어가 마모됨에 따라 자동차 제동거리가 늘어나고 슬립현상이 발생할 가능성이 크다. 따라서 주기적으로 타이어의 마모도를 확인하고 교체해주어야 한다. 기존에는 사람이 직접 마모도를 확인하여 타이어 교체여부를 판단하였다. 하지만 사람에 따라 기준이 다르기 때문에 교체 주기가 불분명해진다. 본 논문에서는 모터 회전각도를 활용한 타이어 마모도 확인 기법을 통해 명확한 교체주기를 마련한다. 명확한 교체주기가 정립됨으로써 타이어로 인한 차량 사고율이 줄어들 것으로 기대되기 때문에 모터 회전 각도를 활용한 타이어 마모도 확인 기법을 제안한다.

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초임계 이산화탄소 사이클을 이용한 연료 재순환 MCFC의 폐열회수 (Waste heat recovery of recirculated MCFC using supercritical carbon dioxide power cycle)

  • 이재윤;안지호;김동섭
    • 플랜트 저널
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    • 제15권2호
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    • pp.42-45
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    • 2019
  • 용융탄산염 연료전지는 폐열의 온도가 높아 하부 사이클을 구성하여 효율을 높일 수 있다. 이러한 목적으로 연료를 재순환하는 용융탄산염 연료전지에 하부 사이클로 증기 터빈 사이클을 적용한 선행 연구가 있었다. 본 연구는 하부 사이클을 증기 터빈 사이클에서 초임계 이산화탄소 사이클로 대체하는 것을 고려하였다. 그리고 출력을 비교하여 하부 사이클을 대체하는 것에 대한 검토를 하였다. 그 결과 현재 개발 단계의 초임계 이산화탄소 사이클의 출력은 증기 터빈 사이클보다 낮지만, 이론적으로 증기 터빈 사이클보다 출력이 더 커질 수 있음을 확인하였다. 만약 초임계 이산화탄소 사이클이 터빈의 등엔트로피 효율을 89%, 압축기의 등엔트로피 효율을 83%, 복열기의 유용도를 0.9의 수준으로 향상 시킨다면 증기 터빈 사이클과 동등한 출력을 낼 수 있다.

Various Alcohols as Electrolysis Suppressants in Zn-air Secondary Batteries

  • Yang, Soyoung;Kim, Ketack
    • Journal of Electrochemical Science and Technology
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    • 제9권4호
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    • pp.339-344
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    • 2018
  • The gelling agent used in Zn-air cells plays a role in improving battery life. It prevents the evaporation of water and diffusion of $Zn^{2+}$ ions away from the current collector. Additional functionality was incorporated by replacing some of the gelling agents with new materials. Alcohols with moderate viscosity, namely maltose, sucrose, poly ethylene glycol 600, and 2-hydroxyethyl cellulose, were used to replace some gelling agents in this work. Among these alcohols, poly ethylene glycol 600 and 2-hydroxyethyl cellulose improved the cycle life of full cells. This improved cycle life was attributed to the inhibition of water electrolysis and the improved cycle life of the anode.

Feasibility of combinational burnable poison pins for 24-month cycle PWR reload core

  • Dandi, Aiman;Lee, MinJae;Kim, Myung Hyun
    • Nuclear Engineering and Technology
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    • 제52권2호
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    • pp.238-247
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    • 2020
  • The Burnable Poison (BP) is very important for all Light Water Reactors in order to hold-down the initial excess reactivity and to control power peaking. The use of BP is even more essential as the excess reactivity increases significantly with a longer operation cycle. In this paper a feasibility study was conducted in order to investigate the benefits of a new combinational BP concept designed for 24-month cycle PWR core. The reference designs in this study are based on the two Korean fuel assemblies; 17 × 17 Westinghouse (WH) design and 16 × 16 Combustion Engineering (CE) design. A modification was done on these two designs to extend their cycle length from 18 months into 24 months. DeCART2D-MASTER code system was used to perform assembly and core calculations for both designs. A preliminary test was conducted in order to choose the best BP suitable for 24-month as a representative for single BP concept. The comparison between the results of two concepts (combinational BP concept and single BP concept) showed that the combinational BP concept can replace the single BP concept with better performance on holding down the initial excess reactivity without violating the design limitations.

초임계 CO2 발전시스템 소개 및 개발동향 (Introduction to supercritical CO2 power conversion system and its development status)

  • 이정익;안윤한;차재은
    • 한국유체기계학회 논문집
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    • 제17권6호
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    • pp.95-103
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    • 2014
  • During the international effort to develop the next generation nuclear reactor technologies, many new power cycle concepts were derived to improve efficiency and reduce the capital cost. Among many innovative power cycles, it was identified that the supercritical $CO_2$ (S-$CO_2$) Brayton cycle technology has a big potential to outperform the existing steam cycle and eventually replace it. The S-$CO_2$ cycle achieves high efficiency with very compact size, which is the ultimate advantage for a power cycle to have. The S-$CO_2$ cycle has a great potential not only for the future nuclear applications but also for general heat sources such as coal, natural gas, and concentrated solar. In this paper, a brief introduction to the S-$CO_2$ power cycle technologies will be first provided, and a short summary of current research and development status of the power cycle technology around the world will be followed. Especially the research works performed by KAIST, KAERI and several related research institutions in Korea will be reviewed in more detail, since they have recently developing a strong infrastructure to test these ideas by constructing a demonstration facility while producing many innovative ideas to improve and realize the concept.

Chemical Stability of Conductive Ceramic Anodes in LiCl-Li2O Molten Salt for Electrolytic Reduction in Pyroprocessing

  • Kim, Sung-Wook;Kang, Hyun Woo;Jeon, Min Ku;Lee, Sang-Kwon;Choi, Eun-Young;Park, Wooshin;Hong, Sun-Seok;Oh, Seung-Chul;Hur, Jin-Mok
    • Nuclear Engineering and Technology
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    • 제48권4호
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    • pp.997-1001
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    • 2016
  • Conductive ceramics are being developed to replace current Pt anodes in the electrolytic reduction of spent oxide fuels in pyroprocessing. While several conductive ceramics have shown promising electrochemical properties in small-scale experiments, their long-term stabilities have not yet been investigated. In this study, the chemical stability of conductive $La_{0.33}Sr_{0.67}MnO_3$ in $LiCl-Li_2O$ molten salt at $650^{\circ}C$ was investigated to examine its feasibility as an anode material. Dissolution of Sr at the anode surface led to structural collapse, thereby indicating that the lifetime of the $La_{0.33}Sr_{0.67}MnO_3$ anode is limited. The dissolution rate of Sr is likely to be influenced by the local environment around Sr in the perovskite framework.