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  • Title/Summary/Keyword: 손상코드

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Effect of Surface Modification of Polyester Cord on the Adhesion of SBR/Polyester (폴리에스터 코드의 표면개질 조건이 SBR/폴리에스터의 접착에 미치는 영향)

  • Park, Y.S.;Chung, K.H.
    • Elastomers and Composites
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    • v.42 no.2
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    • pp.75-85
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    • 2007
  • In this study, the new adhesion system was studied to improve the adhesion strength between polyester cord and rubber matrix. In order to enhance the adhesion strength through polyester cord's surface treatment, the NaOH solution was used. The NaOH solution concentrations of 0.03, 0.05, 0.1, 0.2, 0.5, 1 and 5 wt.% were used in surface modifying the polyester cord. The optimum condition showing the maximum adhesion strength of polyester cord with SBR compound containing bonding agent was at NaOH concentration of 0.05 wt.% with treatment time of 10 minutes. When the NaOH solution concentration was above 1 wt.%, the polyester cord due to the excess surface modification was damaged, and resulted in breakage during the adhesion test. Also, the adhesion strength between polyester and SBR could be improved by coating the polyester cord with triallylcyanurate(TC) adhesive. The drying condition of polyester cord coated with TC attributed to the adhesion strength. The maximum adhesion strength was obtained by using the polyester cord dried at 220C rather than dried at room temperature.

A Study on Cross-correlation Control Schemes on Walsh and Golay Codes Based on the Orthogonal Transformation and BER Performance Evaluation of Asynchronous CDMA System Using the Modified Codes (직교변환에 의한 Walsh 및 Golay 코드의 상호상관 제어방식과 수정된 코드를 사용한 비동기 CDMA 시스템의 비트오율 성능에 관한 연구)

  • Lee, Won-Chang;Kim, Myoung-Jin
    • Journal of the Institute of Convergence Signal Processing
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    • v.9 no.4
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    • pp.304-312
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    • 2008
  • Orthogonal codes like Walsh and Golay codes may have large correlation value when they are not synchronized, hence they are seldom used in asynchronous CDMA systems. Wysocki[1] showed that by multiplying the original Walsh-Hadamard matrix with an orthogonal transformation matrix the resultant matrix sustains orthogonality between row vectors and their cross-correlation can be reduced. Soberly and Wysocki[2] proposed similar scheme on Golay codes. This implies that using the proper orthogonal transformation cross-correlation of Walsh and Golay codes can be reduced, and the transformed codes can be used for user separation in the CDAM reverse link. In this paper we discuss cross-correlation related parameters which affect the performance of an asynchronous CDMA link, and we investigate the correlation properties of the transformed codes. When we designed orthogonal transformation matrices for Walsh and Golay codes, we minimized the maximum value of aperiodic cross-correlation of the codes (ACCmax) or the mean square value of the aperiodic cross-correlation(Rcc) with preserving the orthogonality of the modified codes. We also evaluate the asynchronous CDMA system that uses the transformed Walsh and Golay codes.

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Assessment of SCDAP Using the Full-Length High-Temperature FLHT-2 Test (FLHT-2 실험결과를 이용한 SCDAP코드 평가)

  • Park, Choon-Kyung;Park, Jong-Hwa;Yoo, Kun-Jung;Chae, Sung-Ki
    • Nuclear Engineering and Technology
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    • v.20 no.1
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    • pp.54-64
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    • 1988
  • This paper assesses the models in the SCDAP code using the results of the FLHT-2 test. Calculations show that the SCDAP correctly predicts Ire temperatures, oxidation front movement, overall hydrogen generation and peak generation rate, internal fuel rod pressure, and cladding rupture due to ballooning. A comparison of the calculated results with measured data shows that two phase level is underpredicted, and that radiation heat transfer and auto-catalytic reaction temperature of zircaloy are overpredicted. These models are recommended to be modified. The analysis also shows that the simulation of the gap in a fuel rod improves the code prediction on core damage progression.

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Numerical Evaluation of Excavation Damage Zone Around Tunnels by Using Voronoi Joint Models (Voronoi 절리모델에 의한 터널 주변 굴착손상권(EDZ)의 해석 사례)

  • Park, Eui-Seob;Martin, C. Derek;Synn, Joong-Ho
    • Tunnel and Underground Space
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    • v.18 no.5
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    • pp.328-337
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    • 2008
  • Quantifying the extent and characteristics of the excavation damage zone(EDZ) is important for the nuclear waste industry which relies on the sealing of underground openings to minimize the risk for radionuclide transport. At AECL's Underground Research Laboratory(URL) the Tunnel Sealing Experiment(TSX) was conducted and the tunnel geometry and orientation relative to the stress field had been selected to minimize the potential for the development of an EDZ. The extent and characteristics of the EDZ was measured using velocity profiling and permeability measurements in radial boreholes. The results from this EDZ characterization are used in this paper to evaluate a modeling fir estimating the extent of the EDZ. The methodology used a damage model formulated in the Universal Distinct Element Code and calibrated to laboratory properties. This model was then used to predict the extent of crack initiation and growth around the TSX tunnel and the results compared to the measured damage. The development of the damage zone in the numerical model was found to be in good agreement with the field measurements.

Determining Parameters of Dynamic Fracture Process Analysis(DFPA) Code to Simulate Radial Tensile Cracks in Limestone Blast (석회암 내 방사상 발파균열을 예측하기 위한 동적파괴과정 해석법의 입력물성 결정법에 관한 연구)

  • Kim, Hyon-Soo;Kang, Hyeong-Min;Jung, Sang-Sun;Kim, Seung-Kon;Cho, Sang-Ho
    • Explosives and Blasting
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    • v.31 no.2
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    • pp.6-13
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    • 2013
  • Recently, complaints or environmental problems caused by the noise and dust generated from crusher of the mine and quarry are emerging. Therefore mining facilities such as crushers and mills have been installed in an underground. In order to facilitate crusher equipments in the underground, excavation of large space is required and then the stability of the large space underground structure is an important issue. In this study, the blast experiments, which use a block of the limestone, are performed. Based on the blast experiments, the numerical model was prepared and simulated using dynamic fracture process analysis code(DFPA) with considering the rising time of applied borehole pressure and microscopic tensile strength variation. Comparing the non-dimensional crack length and no-dimensional tensile strength obtained from blast experiments and numerical analyses, the input parameters of DFPA code for predicting a radial tensile crack in limestone blasting were determined.

A Development of Small-diameter Composite Helical Spring for Reinforcement of Optical Fiber Jumper Cord (OJC) (광점퍼코드 (OJC) 보호용 미소 직경 복합재료 스프링 개발)

  • 윤영기;박성도;이연수;윤희석;이우일
    • Composites Research
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    • v.15 no.4
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    • pp.17-22
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    • 2002
  • Small diameter composite helical springs (CS) are developed using a hot plated mold for reinforcement of common optical fiber jumper cord (OJC). The outer diameters of the springs are about 2 ~ 3mm. These springs are inserted into the OJC to protect the damage of an optical fiber from the sudden lateral load. Two types of CS, Yarn type (Y-type) and Band type (B-type), are manufactured to compare the effectiveness for the damage protection. The experimental works were conducted to check the effect of the CS covered around OJC on the mechanical and optical properties. Experimental observations show a considerable effect on the flexural resistance, hence slowing down the deterioration of the optical power by the internal damage of the fiber. Obtained main results are as follows: (1) Y-type CS has better protection abilities to lateral loading than B-types. (2) Compared with bare OJC, CS-OJC has less power loss under the loading. (3) OJC covered with the composite coil spring has a possibility for a practical usage with full fruits.

A Boundary Element Analysis for Damage and Failure Process of Brittle Rock using ERACOD (FRACOD를 이용한 취성 암석의 손상 및 파괴에 대한 경계요소 해석)

  • ;Baotang Shen;Ove Stephansson
    • Tunnel and Underground Space
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    • v.14 no.4
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    • pp.248-260
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    • 2004
  • Damage in brittle rock due to stress increase starts from initiation of microcracks, and then results in failure by forming macro failure planes due to propagation and coalescence of these discrete cracks. Conventionally, continuum approaches using macro-failure criteria or a number of elasto-plastic models have been major solution to implement rock damage and failure. However, actual brittle failure processes can be better described in phenomenological approach if initiation and propagation of discrete fractures are explicitly considered. This study presents damage and failure process of rock using a boundary element code, FRACOD, which has been developed to model fracturing process of rocks. Through a series of numerical uniaxial compressive tests, the feasibility of the developed model was verified, and realistic rock failure process was reproduced considering scale effects in rocks. In addition, the fracturing process and the corresponding rock damage in the vicinity of deep shaft in rock mass were presented as an application of this approach. This approach will be expected to contribute to finding better engineering solutions for the analysis of stability problems in brittle rock masses.

Thickness Measurement of Pipe Using Tangential Radiography (Tangential Radiography를 이용한 배관의 두께 평가법)

  • Lee, S.S.;Kim, Young-H.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.18 no.3
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    • pp.205-210
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    • 1998
  • 이미 오래전부터 국내외에서 석유화학공장 등의 보온 배관에서 보온재를 벗기지 않고 배관의 부식 손상 및 잔존두께를 평가하는데 방사선투과시험법을 적용해 오고 있다. 그러나 배관 용접부의 결함 탐상에 관한 방사선투과법에 대한 국제 및 국내 코드는 이미 마련되어 있지만 배관의 두께와 내부에 존재하는 부착물(deposit) 등의 두께를 측정하는 것에 관련한 국제 및 국내 코드는 미비되어 시험 절차 및 시험 결과에 대한 시비가 근본적으로 존재할 수 밖에 없을 뿐만 아니라 표준화된 시험 기술의 미비로 현장에서 많은 시행착오를 동반하였다. 그러나 최근 이 시험법에 대한 관련 원안(protocol)을 확정하기 위해 각국에서 개별적으로 수행되었던 기존의 연구 결과들이 취합되고 있으며 부족한 부분들에 대한 연구가 국제 공동 연구 형식으로 이뤄지고 있다. 따라서 본 연구에서는 tangential radiography를 적용하여 보온된 배관의 잔존 두께를 평가할 수 있는 시험 방법을 제시하고자 하였다.

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Distributed Data Recording on the Optical Disks using LDPC Codes (광학 저장 매체상에 LDPC 코드를 이용한 데이터의 분산 기록 방법)

  • Kim, Tae-Woong;Ryu, Jun-Kil;Park, Chan-Ik
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.9
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    • pp.710-714
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    • 2009
  • Optical discs' capacity has increased. In case of Blu-Disc, it can store data up to 25 GB. Due to the large capacity, it can substitute tape devices for the use of backup. However, optical discs' surfaces are exposed so that it can lose data easily by exterior damages like scratches. Therefore additional reliability must be provided to maintain data for a long time. In this paper, we suggest a writing technique that gives optical discs additional reliability. Redundant data, generated by LDPC codes, are stored in disc along with the original data. These original data and redundant data are scattered over the disc to avoid losing a large part of data with one scratch. By deploying data with the distance that provides the reliability a user wants, we can enhance optical discs' reliability.

Risk Assessment Technique for Gas Fuel Supply System of Combined Cycle Power Plants (I) : Based on API RBI Procedures (복합화력발전의 가스연료 공급계통에 대한 위험도 평가 기법 연구 (I) : API RBI 절차에 기반한 위험도 평가)

  • Song, Jung Soo;Yu, Jong Min;Han, Seung Youn;Choi, Jeong Woo;Yoon, Kee Bong
    • Journal of Energy Engineering
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    • v.27 no.2
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    • pp.1-13
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    • 2018
  • The proportion of natural gas-fueled power generation is expanding due to the change of domestic energy policy pursuing reduction of dust and increasing clean energy consumption. Natural gas fuels used for the combined-cycle power plants and the district-heating power plants are operated at high temperature and high pressure in the fuel supply system. Accidents due to leakage of the gas such as fire and explosion should be prevented by applying risk management techniques. In this study, risk assessment was performed on the natural gas fuel supply system of a combined power plant based on the API RP 581 RBI code. For the application of the API RBI code, lines and segments of the evaluation target system were identified. Operational data and input information were analyzed for the calculations of probability of failure and consequence of failure. The results of the risk assessment were analyzed over time from the initial installation time. In the code-based evaluation, the gas fuel supply system was mainly affected by thinning, external damage, and mechanical fatigue damage mechanisms. As the operating time passes, the risk is expected to increase due to the external damage caused by the CUI(Corrosion Under Insulation).