• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.239-244
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• 2022

In this study, the key parameters affecting the deterioration of each track type were derived based on field inspections and laboratory tests. The existing track deterioration model was limited to the ballasted tracks, and the deterioration evaluation of concrete tracks was insufficient. In this study, the laboratory test was performed to evaluate the performance and condition of track components to derive the deterioration factors reflecting the characteristics of various track structures. In addition, through analysis of track maintenance history data, parameters affecting track deterioration and maintenance were derived. The key parameters for presenting a track deterioration model based on the track performance of ballasted and concrete tracks through field inspection, track maintenance history data analysis, and performance test of track components using on-site specimens were identified as track support stiffness, Ballast gravel, track settlement and Resilience pad were presented.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.617-626
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• 2019

In this study, we investigated the petrographic characteristics and physical property of the Rock-carved Seated Buddha at Bugmireugam hermitage of Daeheungsa temple in Haenam. The Buddha Statue was carved on micrographic granite, and the rock was composed of the fine quartz encircled by orthoclase. The results of diagnosis for deterioration evaluation have shown a highly damage rate of black contaminants (8.4%) and crack index (6.6). The ultrasonic velocity have detected SW (slightly weathered) grade of weathering coefficient (mean 0.18). Various weathering factor on the surface of the Buddha Statue was affected by precious shelter, and physical property with ultrasonic was directly influenced by the structural characteristics and fissure of host rock.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.208-212
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• 2022

In this paper, we report the effects of temperature on the deterioration of graphite-based negative electrodes during the longterm cycling of lithium-ion batteries (LIBs). After cycling 75 Ah pouch-type LIB full cells at temperatures of 45℃ (45-Cell) and 25℃ (25-Cell) until their end of life, we expected to observe changes in the negative electrode according to the temperature. The thickness of the negative electrode of the cell was greater after cycling; that of the electrode of 45-Cell (144 ㎛) was greater than that of the electrode of 25-Cell (109 ㎛). Cross-sectional scanning electron microscopy analysis confirmed that by-products caused this increase in the thickness of the negative electrode. The by-products that formed on the surface of the negative electrode during cycling increased the surface resistance and decreased the electrical conductivity. Voltage profiles showed that the negative electrode of 25-Cell exhibited an 84.7% retention of the initial capacity, whereas that of 45-Cell showed only a 70.3% retention. The results of this study are expected to be relevant to future analyses of the deterioration characteristics of the negative electrode and battery deterioration mechanisms, and are also expected to provide basic data for advanced battery design.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.73-81
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• 1999

Measurements of ultrasonic signals caused by partial discharges were perlonnrl by using an ultrasonic measurement technique to diagnose the electrical treeing deterioration in an epoxy mold-type power transformer. We also examined the characteristics of tree growth, partial discharge magnitude and ultrasonic pulse number with the increase of the deterioration time. From these results, it was found that the shape of the tree was a branch-type, and the rates of the tree growth were examined when ac voltages of 16[kV] and 20[kV] were applied Ultrasonic pulse number and discharge magnitude were rapidly increased as the length of the tree grows after the middle stage of the deterioration time, and it appeared that ultrasonic pulse number was proportional to discharge magnitude. Attenuation, time-delaying and directivity characteristics of ultrasonic signals propagated into epoxy resin by using ultrasonic oscillation and receiving systems are also re[prted as a basic data of ultrasonic mesasurements in mold-type power transformer.former.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.143-149
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• 2022

As ESS safety issues increase recently, there is a need to more precisely monitor the temperature of the ESS. In this paper, DTS technology for temperature monitoring of ESS batteries is introduced and the temperature measurement principle is explained. The temperature of the battery module is measured using the DTS system, and the thermal deviation between battery cells inside the battery module is analyzed. In order to analyze how thermal imbalance affects the charging and discharging performance of the battery, an accelerated degradation test was conducted. Cycle life characteristics analysis, battery surface temperature change, and AC impedance characteristics were conducted to analyze how the performance of battery cells differs according to temperature conditions.

• Journal of the Korean Geotechnical Society
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• v.30 no.4
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• pp.21-34
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• 2014

This paper studies the time-dependent behaviors of tunnel and surrounding ground due to tunnel deterioration. In the first part, the literature on deterioration characteristics of tunnels was reviewed. In the second part, a numerical analysis was performed to investigate the behavior of concrete lining on the typical section of Korean high-speed rail tunnel (weathered rock) after determination of input variables related to deterioration impact. The result shows that the settlement at the crown of tunnel and surface ground increased up to 7.0% and 30.2% of the total settlements during construction stage, respectively, and the internal convergence reduction of 9.0 mm for concrete linings was generated within 30 years after completion of tunnel construction. Also the loosening height increased up to 2.55 times of tunnel height within 50 years, which is higher than that of Terzaghi's recommendation on ultimate state. Due to this process of extending zones, it is found that additional loads were applied to concrete lining with the axial stress about 3.20~3.66 MPa, which accelerates tunnel deterioration. Finally the quantitative design approach to evaluate time-dependent behavior of lining and surrounding ground due to tunnel deterioration was proposed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1651-1664
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• 2013

Precise analysis on deterioration processes of road pavements is not so simple matter due to severe uncertainty originated from a lot of explanatory variables engaged in. For those reasons, most analytical models for pavement deterioration prediction have often preferred to probabilistic approaches than deterministic models. However, the general probabilistic approaches that treat overall characteristics of population or entire sample would not be suitable for providing detail or localized information on their changing process. Considering the aspects, this paper aimed to suggest a stochastic disaggregation method to analyze the localized deterioration speeds and its variances changed by time and condition states. In addition, life expectancies and their uncertainty were estimated by probabilistic algorithm using the disaggregated stochastic process. For an empirical study, pavement inspection data (crack) accumulated from 2003 to 2010 from Korean national highway network was applied. This study can contribute to securing reliability of life cycle cost analysis, which is one of the primary analyses in road asset management, with much advanced deterioration forecasting functions. In addition, it would be meaningful trials as fundamental research for preventive maintenance strategy that demands essential understanding on changing process of the deterioration speed of pavement.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.188-198
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• 2013

Advancement toward aging society has presented the importance of house planning in consideration of the elderly, increasing the necessity of such planning. Therefore the importance of indoor design guideline for elderly houses has been stressed and the understanding of the aging in regard to this trend will create more mature spaces. In line with this trend the purpose of this study is to study the medical factors related with bathroom interior design guidelines of the existing elderly houses from the viewpoint of deteriorating physical functions due to aging process. In order to research the deterioration of physical functions due to aging literatures of medical and exercise physiology were used and concerning the existing bathroom design guidelines for the aged people, the guideline items of behavior facilitation, physiological maintenance and perceptual maintenance aspects out of Murtha & Lee's user benefit criteria(1976) related with physical functions were selected to research in relation with the knowledge about the deterioration phenomena of physical functions. Physical aging and deterioration aspects were classified from the viewpoint of musculoskeletal disorder, cardiovascular disorder, respiratory disorder, gastronomy disorder, urology disorder, somatosensory disorder, endocrine disorder, immune disorder, nervous disorder and skin diseases and these were utilized in interpreting total 100 items of bathroom design guideline. Because bathroom is the space where many physical movements are done, it had the closest relationship with the deterioration of musculoskeletal health in general and as bathroom is the space where people use water and feel the difference in temperature and moisture more than other spaces, deterioration of skin and somatosensory health had the next closest relationship. The result of this study revealed that regarding the deterioration of physical functions of the elderly people in aspect of their perceptibility as designers will design creatively and sincerely based on its relationship with nervous system in future, the result of this study will be used to develop better spatial designs efficiently to meet for the aging society.

• Congress of the korean instutite of fire investigation
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• 2010.06a
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• pp.66-81
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• 2010

In this study, we experimented and analyzed deterioration characteristics of outlets and power cord sets caused by poor contact. Electrical waveforms were measured according to load size and elapsed time. After that, surface structure and deteriorated characteristics of conductive materials and insulators were analyzed. We hope that the results will be applicable to electrical fire prevention and accidents analysis.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.339-339
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• 2002