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  • Title/Summary/Keyword: mechanical resistance

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Mechanical Properties of Zelkova Serrata Makino in Accelerated Weathering Test (촉진 열화 느티나무 부재의 역학적 특성)

  • Kim, Gwang-Chul;Park, Chun-Young
    • Journal of the Korea Furniture Society
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    • v.26 no.4
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    • pp.392-397
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    • 2015
  • This study was carried out to analyze the effects on mechanical properties of deteriorated wood member by outdoor condition. The surface color, mechanical properties and structural stability of traditional wooden structures, exposed in water and UV, could be changeable. For the purpose, accelerated weathering test based on outdoor condition was carried out. The weathering time levels were composed 0, 500, 1000, 1,500 and 2,000 hours and mechanical properties were evaluated on each specimen according to weathering time level. Bending properties were decreased on weathering but recovered after 1,000 hours. Fatigue and impact strength were decreased to 1,000 hours and did not changed since then. Abrasion resistance was minimized in 1,000 hours. This results could be utilized for effectively stability management of traditional wooden structures and members.

Electromagnetic Environment of Transmission Line Based on Full Parameter Online Estimation

  • Sun, Zidan;Zhou, Xiaofeng;Liang, Likai;Mo, Yang
    • Journal of Information Processing Systems
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    • v.16 no.2
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    • pp.394-405
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    • 2020
  • The parameters of transmission lines have an influence on the electromagnetic environment surrounding the line. This paper proposes a method based on phasor measurement unit (PMU) and supervisory control and data acquisition (SCADA) to achieve online estimation of transmission line full parameters, such as resistance, reactance and susceptance. The proposed full parameter estimation method is compared with the traditional method of estimating resistance independently based on SCADA system. Then, the electromagnetic environment is analyzed based on the different parameter estimation methods. The example results illustrate that online estimation of transmission line full parameters is more accurate in the analysis of electromagnetic environment, which further confirms its necessity and significance in engineering application.

Development of Intelligent Monitoring System for Welding Process Faults Detection in Auto Body Assembly (자동차 차체 제조 공정에서 용접 공정 오류 검출을 위한 지능형 모니터링 시스템 개발)

  • Kim, Tae-Hyung;Yu, Ji-Young;Rhee, Se-Hun;Park, Young-Whan
    • Journal of Welding and Joining
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    • v.28 no.4
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    • pp.81-86
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    • 2010
  • In resistance spot welding, regardless of the optimal condition, bad weld quality was still produced due to complicated manufacturing processes such as electrode wear, misalignment between the electrode and workpiece, poor part fit-up, and etc.. Therefore, the goal of this study was to measure the process signal which contains weld quality information, and to develop the process fault monitoring system. Welding force signal obtained through variety experimental conditions was analyzed and divided into three categories: good, shunt, and poor fit-up group. And then a monitoring algorithm made up of an artificial neural network that could estimate the process fault of each different category based on pattern was developed.

Corrosion and Corrosion Fatigue Characteristics of Artificially Sensitized STS 304 (STS304 열화재의 부식및 부 식피로특성)

  • Han, Ji-Won;Bae, Dong-Ho
    • Journal of the Korean Society of Safety
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    • v.25 no.6
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    • pp.28-33
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    • 2010
  • Stainless steel is useful material for various industrial facilities such as the nuclear and steam power plant and the heavy chemical industry due to its good corrosion resistance and mechanical properties. However, it has also a large problem that is sensitized in the welding process and its corrosion resistance and mechanical properties decreases by sensitization. Thus, corrosion and corrosion fatigue characteristics of artificially sensitized austenitic STS304 were investigated through the EPR test and corrosion fatigue test. Obtained results are as follows: 1) According to the sensitizing period increase, Cr deficiency layer is linearly expanded. 2) Degree of sensitization(Ia/Ir) proportionally increased with sensitizing period. However, after 4hrs, it showed constant value. 3) Cr-carbide(Cr23C6) in the grain boundary increased as sensitizing period increases until six hours. 4) corrosion fatigue strength of sensitized STS304 were remarkably reduced compare to non-sensitized ones.

The effect of buffing on particle removal in Post-Cu CMP cleaning (Post-Cu CMP cleaning에서 연마입자 제거에 buffing 공정이 미치는 영향)

  • Kim, Young-Min;Cho, Han-Chul;Jeong, Hae-Do
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.537-537
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    • 2008
  • Copper (Cu) has been widely used for interconnection structure in intergrated circuits because of its properties such as a low resistance and high resistance to electromigration compared with aluminuim. Damascene processing for the interconnection structure utilizes 2-steps chemical mechanical polishing(CMP). After polishing, the removal of abrasive particles on the surfaces becomes as important as the polishing process. In the paper, buffing process for the removal of colloidal silica from polished Cu wafer was proposed and demonstrated.

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Manufacturing and Characterization of Nano-composites with Chemically Functionalized Multiwalled Carbon Nanotubes (기능화된 다중벽 탄소나노튜브 복합재료의 제조 및 물성 평가에 대한 연구)

  • Park, Joo-Hyuk;Kim, Tae-Goo
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.126-131
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    • 2004
  • Chemically modified multiwalled carbon nanotubes with acids were incorporated into a epoxy matrix by in situ polymerization process, to improve the transfer of mechanical load through chemical bonds, which were demonstrated by infrared spectroscopy. And the mechanical properties of epoxy/carbon nanotube composites were measured to investigate the role of carbon nanotubes. The epoxy/carbon nanotube composites shows higher tensile strength and wear resistance than existing epoxy, with 1 or 2 wt. % addition of functionalized carbon nanotubes. The tensile strength with 7 wt. % carbon nanotibes is increased by a 28% and the wear resistance in exceptionally increased by an outstanding 100 times.

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Influence of Compositions of Sintered Ti-Ni Alloys on their Thermo-mechanical Properties

  • Kyogoku, Hideki;Ikeda, Tetsuya;Komatsu, Shinichiro
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.81-82
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    • 2006
  • This paper presents the influence of the compositions of sintered Ti-Ni alloys on their thermo-mechanical properties. The Ti-Ni alloys having various compositions from 50at%Ni to 51at%Ni were sintered using elemental Ti and Ni powders by a pulse-current pressure sintering equipment. The deformation resistance in stress-strain curves increased with an increase in Ni content. In the case of Ti-50at%Ni, tensile strength and elongation were more than 500 MPa and 7%, respectively. The increase in Ni content also makes the transformation temperatures lower. The deformation resistance at a test temperature change from 293K and 353K in isothermal tensile test increased with elevating test temperature.

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Effects of mixed contents of carbon nanoreinforcements on the impact resistance of epoxy-based nanocomposites

  • Ayatollahi, M.R.;Naeemi, A.R.;Alishahi, E.
    • Structural Engineering and Mechanics
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    • v.56 no.2
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    • pp.157-167
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    • 2015
  • The impact behavior of epoxy-based nanocomposites reinforced with carbon nano tube (CNT), carbon nano fiber (CNF) and mixed contents of these nanoparticles was investigated using Izod impact test. The results showed that while the impact strength of nanocomposites containing 1 wt% of CNT and 1 wt% of CNF increased 19% and 13% respectively, addition of mixed contents of these nanofillers (0.5-0.5 wt%) demonstrated higher improvement (21%) in the impact resistance. The trend of the results is explained on the basis of different fracture mechanisms of nanocomposites. Furthermore, the fracture surface of specimens and the dispersion state of nanoenhancers have been studied using scanning electron microscopy (SEM) photographs.

The Effect of Additive to Corrosion Resistance of Heavy Anti-Corrosive Paint (중방식 도료의 내식성에 미치는 첨가제의 영향)

  • Moon, Kyung-Man;Cho, Hwang-Rae;Lee, Myung-Hoon;Kim, Hyun-Myung;Lee, In-Won;Chun, Ho-Hwan
    • Journal of Ocean Engineering and Technology
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    • v.21 no.3 s.76
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    • pp.65-70
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    • 2007
  • There are many kinds of protection methods for marine structures, with varyingeconomical and environmental advantages. The coating protection method is being widely used in both continental and marine structures. In this study, by adding some additives, such as Zn powder(Zn), carbon black(CB) to epoxy anti-corrosive paint, the effect on the corrosion resistance was investigated throughan electrochemical method. The additive of Zn(20)+CB(10) showed the lowest passivity current density. Polarization resistance in both cyclic voltammogram and impedance measurement of an additive of Zn(20)+CB(10) was also the largest value, compared to other additives. Furthermore, rusting and bubbling was not observed on the surface of the test specimen with the additive of Zn(20)+CB(10), compared to other specimens. It is suggested that the corrosion resistance of the anti-corrosive paint can be improved by using some additives.

Measurement Criteria for Drag-Sled Type Slip Resistance Tester Based on Human Gait and Slip (인간의 보행 및 미끄러짐 특성에 기반한 끌기형 미끄러짐 저항 측정 조건)

  • Park, Jae-Suk;Kwon, Hyuck-Myun;Oh, Whan-Sup
    • Journal of the Korean Society of Safety
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    • v.27 no.5
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    • pp.179-184
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    • 2012
  • This study was performed to find out the measurement criteria of slip resistance from analysis of human gait and slips. Many kinds of slip resistance testers were developed based on mechanical friction testers. But, there are, as yet, no unambiguous slip resistance measurement methodologies and generally accepted safety criteria or safety thresholds for estimating slipping hazard exposures. Also, there are variety of measuring conditions between those testers. The measurement criteria should be tested within the range of human slipping conditions observed in biomechanical studies. It's results should clearly consider whether the devices reflect the human slipping conditions. In this study a dragsled type friction tester, which was constructed in accordance with ISO 15133 basically, was used. Test conditions were set in order to determine the range of measurement criteria. It is shown that drag velocity should be more than 1 m/s, acceleration be more than 10 m/s2, contact time be less than 0.1sec, and contact pressure be within 350~400 kPa.