• Title/Summary/Keyword: Artificial-Aging

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Evaluation of Ultrasonic Nonlinear Characteristics in Artificially Aged Al6061-T6 (인공시효된 Al6061-T6의 초음파 비선형 특성 평가)

  • Kim, Jongbeom;Lee, KyoungJun;Jhang, Kyung-Young;Kim, ChungSeok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.34 no.3
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    • pp.220-225
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    • 2014
  • Generally, the nonlinearity of ultrasonic waves is measured using a nonlinear parameter ${\beta}$, which is defined as the ratio of the second harmonic's magnitude to the power of the fundamental frequency component after the ultrasonic wave propagates through a material. Nonlinear parameter ${\beta}$ is recognized as an effective parameter for evaluating material degradation. In this paper, we evaluated the nonlinear parameter of Al6061-T6 which had been subjected to an artificial aging heat treatment. The measurement was using the transmitted signal obtained from contact-type transducers. After the ultrasonic test, a micro Vickers hardness test was conducted. From the result of the ultrasonic nonlinear parameter, the microstructural changes resulting from the heat treatment were estimated and the hardness test proved that these estimates were reasonable. Experimental results showed a correlation between the ultrasonic nonlinear parameter and microstructural changes produced by precipitation behavior in the material. These results suggest that the evaluation of mechanical properties using ultrasonic nonlinear parameter ${\beta}$ can be used to monitor variations in the mechanical hardness of aluminum alloys in response to an artificial aging heat-treatment.

Surface Characterization of Silicone Rubber for Outdoor Insulation by Measurement of Surface Voltage Decay

  • Youn, Bok-Hee;Huh, Chang-Su;Cho, Han-Gu
    • KIEE International Transactions on Electrophysics and Applications
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    • v.12C no.4
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    • pp.214-219
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    • 2002
  • The influence of ultraviolet (UV) irradiation and corona on the surface degradation of high temperature vulcanized (HTV) silicone rubber used for outdoor insulation through measuring surface voltage decay after corona charging, surface resistivity, contact angle and X-ray photoelectron spectroscopy (XPS) analysis was studied. The surface resistivity calculated by the surface voltage decay was compared with a value directly obtained from the three electrode method having the guard ring electrode. A good agreement between the two methods for surface resistivity was obtained. UV treated specimens showed the slower decrease of surface voltage decay, while the corona exposed specimens showed a dramatically faster decrease. Although both artificial treatments cause the same oxidative products, which was confirmed with XPS, we could distinguish the difference between the reactions of the two treatments by monitoring the surface voltage decay on corona-charged specimen. In addition, we could derive the specific surface states of the silicone rubber treated by accelerated artificial aging factors and the degradation process.

Effects of Surface Charges on Hydrophobicity and Surface Potential Decay with Various Surface States of Silicone Rubber for Outdoor Insulator (옥외용 실리콘 절연재료의 발수성에 미치는 표면전하의 영향과 표면 상태에 따른 표면전위 감쇠)

  • 연복희;박충렬;허창수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.8
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    • pp.678-686
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    • 2002
  • This paper presents the effects of accumulation of surface charges on hydrophobic level and the changes of surface potential decay with various artificial environment treatments on high temperature vulcanized (HTV) silicone rubber used for outdoor insulating material. For this study, the charging apparatus by corona discharge, in which grid electrode was installed between the main corona and ground electrode, was used. From this study, it was found that the accumulation of surface charges above a critical surface potential on silicone insulating materials could lead to the temporary loss of surface hydrophobicity. In addition, corona stress and water absorption stress increase the decay rate of surface charges of HTV silicone rubber, while ultraviolet (UV) stress causes longer decay time. We could conclude that the effects of surface charges on hydrophobicity level and the changes of surface state by various artificial treatments were found through a trend of surface potential decay.

Monitoring system technology of patients' lifestyles

  • Hahn, James
    • Korean Journal of Artificial Intelligence
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    • v.2 no.1
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    • pp.4-6
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    • 2014
  • These days, aging, the aged and patients rapidly increased to produce problems, for instance, rapid increase of demand on medical service, higher medical expenses, low quality of the elderly's lives, shortage of physicians and nurses, and others [1]. These days, not only IT technology but also medical technology has taken the lead in settlement of the problems. Patients see a doctor to be given medical treatment and service when they are sick to have difficulty. The study investigated lifestyle monitoring system of chronic disease patients to indicate variation depending upon time. The health care is likely to solve problems of the elderly and chronic disease patients and to satisfy desire of better life quality by living healthy life and to diagnose diseases and give medical treatment and to give solutions in accordance with changes of paradigm of medical services.

The comparison of maximum output power of PV module by solar cell breakage (PV 모듈에서 셀의 파손에 따른 전기적 출력 특성 비교)

  • Lee, Jin-Seob;Kang, Gi-Hwan;Park, Chi-Hong;Yu, Gwon-Jong;Ahn, Hyung-Gun;Han, Deuk-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.9-10
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    • 2007
  • In this paper, we investigated the effect of solar cell breakage on maximum output power of PV module. The test result using artificial light source didn't give any change in output power in case of crack near electrical ribbon. Also, there was a reduction in output power in case of increasing of crack area far from electrical ribbon. But, this experiment is under artificial light source test method. So, when such a PV module is outdoor for a long time, there would be problems on electrical output power and durability because of thermal aging phenomenon of solar cell breakage.

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Modeling the compressive strength of cement mortar nano-composites

  • Alavi, Reza;Mirzadeh, Hamed
    • Computers and Concrete
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    • v.10 no.1
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    • pp.49-57
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    • 2012
  • Nano-particle-reinforced cement mortars have been the basis of research in recent years and a significant growth is expected in the future. Therefore, optimization and quantification of the effect of processing parameters and mixture ingredients on the performance of cement mortars are quite important. In this work, the effects of nano-silica, water/binder ratio, sand/binder ratio and aging (curing) time on the compressive strength of cement mortars were modeled by means of artificial neural network (ANN). The developed model can be conveniently used as a rough estimate at the stage of mix design in order to produce high quality and economical cement mortars.

Data-Driven Approach for Lithium-Ion Battery Remaining Useful Life Prediction: A Literature Review

  • Luon Tran Van;Lam Tran Ha;Deokjai Choi
    • Smart Media Journal
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    • v.11 no.11
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    • pp.63-74
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    • 2022
  • Nowadays, lithium-ion battery has become more popular around the world. Knowing when batteries reach their end of life (EOL) is crucial. Accurately predicting the remaining useful life (RUL) of lithium-ion batteries is needed for battery health management systems and to avoid unexpected accidents. It gives information about the battery status and when we should replace the battery. With the rapid growth of machine learning and deep learning, data-driven approaches are proposed to address this problem. Extracting aging information from battery charge/discharge records, including voltage, current, and temperature, can determine the battery state and predict battery RUL. In this work, we first outlined the charging and discharging processes of lithium-ion batteries. We then summarize the proposed techniques and achievements in all published data-driven RUL prediction studies. From that, we give a discussion about the accomplishments and remaining works with the corresponding challenges in order to provide a direction for further research in this area.

Study on the Image-Based Concrete Detection Model (이미지 기반 콘크리트 균열 탐지 검출 모델에 관한 연구)

  • Kim, Ki-Woong;Yoo, Moo-Young
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.97-98
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    • 2023
  • Recently, the use of digital technology in architectural technology is gradually increasing with the development of various industrial technologies. There are artificial intelligence and drones in the field of architecture, and among them, deep learning technology has been introduced to conduct research in areas such as precise inspection of buildings, and it is expressed in a highly reliable way. When a building is deteriorated, various defects such as cracks in the surface and subsidence of the structure may occur. Since these cracks can represent serious structural damage in the future, the detection of cracks was conducted using artificial intelligence that can detect and identify surface defects by detecting cracks and aging of buildings.

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The Effect of Oxygen Absorbent on Aged Characteristics of Hanji during Biological Artificial Aging by Aspergillus versicolor and Penicillium polonicum (산소흡수제 처리가 Aspergillus versicolor와 Penicillium polonicum에 의한 한지의 생물열화 특성에 미치는 효과)

  • Jeong, Hye Young;Choi, Kyoung-Hwa;Park, Ji Hee;Seo, Jin Ho
    • 보존과학연구
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    • s.32
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    • pp.137-153
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    • 2011
  • Paper cultural heritages in museums and libraries are deteriorated by many biological factors like as fungi, insects, bacteria and rodents and get irreversibly damaged. Especially, paper components like as cellulose, hemicellulose, lignin, pectins, tannins, proteins and mineral additives are good nourishment for microorganism. Through some studies on fungi causing the aging of paper materials, Aspergilli (about 30%) and Penicilli (more than 30%) are the most common among 300 different kinds of microorganism that caused the biological aging of paper cultural heritages in museums and libraries. At present, various treatments are attempted to control the biodeterioration by these fungi. Especially, it is focused on the control of environmental factors such as humidity, temperature and oxygen. In this study, the oxygen absorbent was used to control oxygen, one of the these favorable conditions during the biological aging of Hanji by Aspergillus versicolor and Penicillium polonicum and then the effect on prevention in aging by this treatment was investigated. In result, the oxygen absorbent treatment had the good effect on prevention in aging during the biological aging by two species of fungi.

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Artificial Intelligence-based Leak Prediction using Pipeline Data (관망자료를 이용한 인공지능 기반의 누수 예측)

  • Lee, Hohyun;Hong, Sungtaek
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.7
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    • pp.963-971
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    • 2022
  • Water pipeline network in local and metropolitan area is buried underground, by which it is hard to know the degree of pipe aging and leakage. In this study, assuming various sensor combinations installed in the water pipeline network, the optimal algorithm was derived by predicting the water flow rate and pressure through artificial intelligence algorithms such as linear regression and neuro fuzzy analysis to examine the possibility of detecting pipe leakage according to the data combination. In the case of leakage detection through water supply pressure prediction, Neuro fuzzy algorithm was superior to linear regression analysis. In case of leakage detection through water supply flow prediction, flow rate prediction using neuro fuzzy algorithm should be considered first. If flow meter for prediction don't exists, linear regression algorithm should be considered instead for pressure estimation.