• Title, Summary, Keyword: Cladding

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Mode Coupling within Inner Cladding Fibers

  • Lee, Byeong-Ha;Eom, Tae-Jung;Kim, Myoung-Jin;Paek, Un-Chul;Park, Tae-Sang
    • Journal of the Optical Society of Korea
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    • v.7 no.2
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    • pp.53-58
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    • 2003
  • We report the formation of inner cladding modes in the optical fiber having an inner cladding structure. The inner cladding layer located between the core- and the cladding- layers of a conventional fiber might have, so called, inner cladding mode(s). The brief history of the inner cladding fiber and the spectral properties of the inner cladding mode are presented. By utilizing fiber gratings, the spectral properties of the inner cladding mode formed in Dispersion Compensating Fiber (DCF) are discussed. It was observed that one resonant peak of a long-period fiber grating was not sensitive to the variation on the cladding surface. With a fiber Bragg grating, a small group of unusual resonant Peaks was observed between the main Bragg Peak and the series of usual Peaks resulted from the mode coupling to counter-propagating cladding modes. Within the DCF by using fiber gratings, it is noted, at least one mode can be coupled to the inner cladding mode and a few outer cladding modes are severely affected by the inner cladding of the fiber.

Out-of-pile Characteristics of Advanced Fuel Cladding (HANA alloys)

  • Park, Jeong-Yong;Park, Sang-Yun;Lee, Myung-Ho;Choi, Byung-Kwon;Baek, Jong-Hyuk;Kim, Jun-Hwan;Kim, Hyun-Gil;Jeong, Yong-Hwan;Kim, Gyu-Tae;Jung, Youn-Ho
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.423-424
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    • 2005
  • The performance of HANA claddings was evaluated in out-of-pile conditions. All the performance test results revealed that HANA claddings were superior to the reference claddings such as Zircaloy-4 and A-cladding. Corrosion resistance was improved by 60 to 70% compared to the commercial claddings. Creep, burst, tensile, LOCA, wear and microstructural properties were shown to be as good as the commercial claddings.

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Development of A Laser Cladding Process Monitoring System (I) -Extraction of optimal process variables (레이저클래딩 공정 모니터링 시스템 개발 (I) - 최적공정변수 추출)

  • 오기석;윤길상;조명우;김문기
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.89-92
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    • 2000
  • Laser claddmg 1s thc deposition of material on the surface of a part or workpiece. Cladding of metals produces a 100% dense metallurgically-bonded coating with minimal dilution for enhanced corrosion, abrasion and wear resistance. Despite of minimal heat Input and reduced processing time, cladding quality 1s affected by various process condition such as laser power and feed rate. Therefore, it is necessary to develop the momtoring and control methods of laser cladding process for the best cladding quality. In this paper, laser cladding monitoring system using CCD camera for measuring cladding pool shape, and photo-diode sensor for detecting optical signal emitted from the cladding front is introduced The variables extracted using this system can be apphed to control the laser cladding system to achieve the best claddmg results..

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Temperature Field and Cooling Rate of Laser Cladding with Wire Feeding

  • Kim, Jae-Do;Peng, Yun
    • Journal of Mechanical Science and Technology
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    • v.14 no.8
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    • pp.851-860
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    • 2000
  • Temperature field and cooling rate are important parameters to influence the properties of clad layer and the heat affected zone. In this paper the temperature field and cooling rate of laser cladding are studied by a two-dimensional time-dependent finite element model. Experiment has been carried out by Nd:YAG laser cladding with wire feeding. Research results indicate that at the beginning of cladding, the width and depth of melt pool increase with cladding time. The cooling rate is related to position, cladding time, cladding speed, and preheating temperature. The temperature near melt pool changes rapidly while the temperature far from melt pool changes slowly. With the increase of cladding time, cooling rate decreases. The further the distance from the melt pool, the lower the temperature and the slower the cooling rate. The faster the cladding speed, the faster the cooling rate. The higher the preheating temperature, the slower the cooling rate. The FEM results coincide well with the experiment results.

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Embrittlement Behavior of Zirconium Alloy in Quenching Heat Treatment (급랭 열처리시 지르코늄 합금의 취성 거동)

  • Kim, Jun Hwan;Lee, Jong Hyuk;Choi, Byoung Kwon;Jeong, Yong Hwan
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.4
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    • pp.216-222
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    • 2004
  • Study was focused on the quenching embrittlement property of Zircaloy-4 cladding simulated Loss Of Coolant Accident (LOCA) environment in terms of high temperature oxidation and phase transformation. Property in LOCA condition of advanced cladding that contained Nb element was also investigated. Claddings were oxidized at given temperature and given time followed by water quenching. The results showed that ${\beta}$ phase which formed at quenching stage has an influence on cladding property. In case of advanced cladding, Nb retards cladding oxidation, thus enhances quenching resistance.

Development and validation of a numerical model for steel roof cladding subject to static uplift loads

  • Lovisa, Amy C.;Wang, Vincent Z.;Henderson, David J.;Ginger, John D.
    • Wind and Structures
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    • v.17 no.5
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    • pp.495-513
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    • 2013
  • Thin, high-strength steel roof cladding is widely used in residential and industrial low-rise buildings and is susceptible to failure during severe wind storms such as cyclones. Current cladding design is heavily reliant on experimental testing for the determination of roof cladding performance. Further study is necessary to evolve current design standards, and numerical modelling of roof cladding can provide an efficient and cost effective means of studying the response of cladding in great detail. This paper details the development of a numerical model that can simulate the static response of corrugated roof cladding. Finite element analysis (FEA) was utilised to determine the response of corrugated cladding subject to a static wind pressure, which included the anisotropic material properties and strain-hardening characteristics of the thin steel roof cladding. The model was then validated by comparing the numerical data with corresponding experimental test results. Based on this comparison, the model was found to successfully predict the fastener reaction, deflection and the characteristics in deformed shape of the cladding. The validated numerical model was then used to predict the response of the cladding subject to a design cyclone pressure trace, excluding fatigue effects, to demonstrate the potential of the model to investigate more complicated loading circumstances.