• Title, Summary, Keyword: Degradation

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Analysis of Luminance Degradation characteristics of OLED using the Hotplate (핫플레이트를 이용한 OLED의 휘도열화특성 분석)

  • Kim, Yun-Cheol;Lee, Duek-Jung;Jang, Joong-Soon
    • Journal of Applied Reliability
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    • v.16 no.4
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    • pp.356-363
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    • 2016
  • Purpose: The purpose of this study is to propose efficiency of equipment testing the luminance degradation of OLED. Methods: The degradation model of Exponential model and Stretched exponential model is analyzed by goodness of fit test using calculated R-square. The degradation model having the higher R-square is finally selected. Scale parameter and Shape parameter using the selected degradation model is estimated. The activation energy and current density n using peck model among the accelerated model is estimated. the estimated parameters are analyzed by t-test. Results: The results of t-test show that the estimated parameters on chamber and hotplate are equal statistically. we can know the similarity of the luminance degradation rate and degradation pattern on chamber and hotplate. Conclusion: The result of the degradation test on chamber and hotplate is similar. when the accelerated degradation test on the panel of the OLED TV is performed, hotplate is requiring less samples, time and cost than chamber. so the accelerated degradation test on the panel of the OLED TV using the hoplate is efficient of time and cost.

Sequential microbial-photocatalytic degradation of imidacloprid

  • Sharma, Teena;Kaur, Manpreet;Sobti, Amit;Rajor, Anita;Toor, Amrit Pal
    • Environmental Engineering Research
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    • v.25 no.4
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    • pp.597-604
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    • 2020
  • In the present study, the application of sequential biological and photocatalytic process was evaluated as a feasible process for the degradation of imidacloprid (IMI) in soil. Photocatalysis was carried out as a post and pre-treatment to the biological process as Microbial Photocatalytic (MP) and Photocatalytic Microbial (PM), respectively, to enhance the degradation and mineralization of IMI in soil. By both the processes, there was an enhancement in the percentage degradation of IMI i.e 86.2% for PM and 94.6% for MP process. The obtained results indicate that MP process is apparently more efficient in degradation of IMI which was observed with 15 days of biological treatment followed by 18 h of photocatalytic degradation (15 d + 18 h). The present work also reveals that though the difference in terms of the degradation of IMI after 5 d + 18 h, 10 d + 18 h & 15 d+ 18 h of MP process is not drastic, yet significant variation has been observed in terms of mineralization that truly signifies the removal of IMI from the soil. The LC analysis has shown that the intermediates formed during MP process are more and smaller in comparison to PM process, which further provides evidence that MP process is better than PM process for effective degradation of IMI in soil.

Service Life Prediction of Components or Materials Based on Accelerated Degradation Tests (가속열화시험에 의한 부품·소재 사용수명 예측에 관한 연구)

  • Kwon, Young Il
    • Journal of Applied Reliability
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    • v.17 no.2
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    • pp.103-111
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    • 2017
  • Purpose: Accelerated degradation tests can speed time to market and reduce the test time and costs associated with long term reliability tests to verify the required service life of a product or material. This paper proposes a service life prediction method for components or materials using an accelerated degradation tests based on the relationships between temperature and the rate of failure-causing chemical reaction. Methods: The relationship between performance degradation and the rate of a failure-causing chemical reaction is assumed and least square estimation is used to estimate model parameters from the degradation model. Results: Methods of obtaining acceleration factors and predicting service life using the degradation model are presented and a numerical example is provided. Conclusion: Service life prediction of a component or material is possible at an early stage of the degradation test by using the proposed method.

A Case Study of Degradation Analysis for the Passenger Vehicles Shock Absorber (승용차량용 쇽업소버의 열화분석 사례연구)

  • Song, Hyun-Seok;Seo, Young-Kyu;Jung, Do-Hyun;Jang, Joong-Soon;Kim, Eunkyu;Park, Boo-Hee
    • Journal of Applied Reliability
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    • v.17 no.3
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    • pp.181-187
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    • 2017
  • Purpose: The purpose of this study is to estimate the lifetime of commercial passenger vehicles shock absorber using degradation test and data. Method: The degradation factor of shock absorber was determined to be a damping force using FMEA. Degradation test was performed on damping force under real world usage condition and analysed the degradation data. Results: To estimate the lifetime of shock absorber, a degradation model was developed and a numerical example was provided. Conclusion: Evaluation of the lifetime of commercial and military vehicles shock absorber will be possible by using the proposed degradation analysis method.

Modeling and Analysis of Accelerated Degradation Testing Data for a Solid State Drive (SSD) (Solid State Drive(SSD)에 대한 가속열화시험 데이터 모델링 및 분석)

  • Mun, Byeong Min;Choi, Young Jin;Ji, You Min;Lee, Yong Jung;Lee, Keun Woo;Na, Han Joo;Yang, Joong Seob;Bae, Suk Joo
    • Journal of Applied Reliability
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    • v.18 no.1
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    • pp.33-39
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    • 2018
  • Purpose: Accelerated degradation tests can be effective in assessing product reliability when degradation leading to failure can be observed. This article proposes an accelerated degradation test model for highly reliable solid state drives (SSDs). Methods: We suggest a nonlinear mixed-effects (NLME) model to degradation data for SSDs. A Monte Carlo simulation is used to estimate lifetime distribution in accelerated degradation testing data. This simulation is performed by generating random samples from the assumed NLME model. Conclusion: We apply the proposed method to degradation data collected from SSDs. The derived power model is shown to be much better at fitting the degradation data than other existing models. Finally, the Monte Carlo simulation based on the NLME model provides reasonable results in lifetime estimation.

The Degradation of Phenolic Compounds by Lignolytic Streptomyces strains (Lignin을 분해하는 Streptomyces strainsdop 의한 페놀화합물의 분해)

  • 김태전
    • Journal of Environmental Health Sciences
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    • v.26 no.3
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    • pp.86-91
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    • 2000
  • The purpose of this was to investigate the degradation efficiency of phenol compounds(catechol, ferulic acid, protocatechuic acid, syringic acid, vanillic acid) by Streptomyces halstedii scabies SAI-36, Streptomyces avendulas SA2-14, and Strptomyces badius(ATCC 39117, control group). The results were as follows: Catechol showed the degradation efficiency that is lower than 50% in three strains. Ferulic acid and vanillic acid showed high degradation efficiency of 98.8% and 94.5% respectively by Streptomyces lavendulas SA2-14. protocatechuic acid and syringicacid showed high degradation efficiency of 89.6% and 77.9%. The degradation efficiency of catechol by Streptomyces halstedii scabies SAI-36, Streptomyces lavendulas SA2-14 and Streptomyces badius(ATCC 39117) was low as 49.2%, 40.2% and 20.2% respectively. But the degradation of other phenolic compoumds except catechol by Streptomyces laven-dulas SA2-36 and Streptomyces badius(ATCC 39117). The results demonstrated that two experimental strains are superior ability to control group in degradation of phenol compounds and Streptomyces lavendulas SA2-14 was superior of two experimental strain. This results were consistent with previous research results that Streptomyces lavendulas SA2-14 was the best strain in degradation ability for lignin, decoloration abilities for variousdyes, and various enzyme production abilities. Therefore, it is suggested that lignin can be used as a indicator when selecting Actinomycetes for degradation of non-degradable materials such as phenol compounds.

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A Study on Electrochemical Evaluation Method of Toughness Degradation for 12%Cr Steel (II) (12%Cr강 인성열화도의 전기화학적 평가법에 대한 연구(II))

  • Kim, Chang-Hui;Seo, Hyun-Uk;Yoon, Kee-Bong;Park, Ki-Sung;Kim, Seoung-Tae
    • Proceedings of the KSME Conference
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    • pp.268-273
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    • 2001
  • Fossil power plants operated in high temperature condition are composed of components such as turbine, boiler, and piping system. Among these components, turbine blades made with 12%Cr steel operate at a temperature above $500^{\circ}C$. Due to the long term service, turbine blades experience material degradation manifested by change in mechanical and microstructural properties. The need to make life assessment and to evaluate material degradation of turbine blade is strongly required but in reality, there is a lack of knowledge in defining failure mechanism and fundamental data for this component. Therefore, in making life assessment of turbine blade, evaluation of material degradation must be a priority. For this purpose, evaluation of toughness degradation is very important. The major cause of toughness degradation in 12Cr turbine blade is reported to be critical corrosion pitting induced by segregation of impurity elements(P etc.), coarsening of carbide, and corrosion, but the of materials for in-service application. In this study, the purpose of research is focused on evaluating toughness degradation with respect to operation time for 12%Cr steel turbine blade under high temperature steam environment and quantitatively detecting the degradation properties which is the cause of toughness degradation by means of non-destructive method, electrochemical polarization.

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Species identification and microscopic structure of ancient wood excavated from the remains( II ) -Degradation of ancient woods- (출토고목재의 수종과 조직구조에 관한 연구( II ) -출토고목재의 부후형태-)

  • KANG, A. K.;PARK, S. J.
    • Journal of Conservation Science
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    • v.2 no.2
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    • pp.15-24
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    • 1993
  • To understand the morphological change of ancient woods, samples classified by cell type, burial environment and species were collected and observed using microscopy. Decay of wood by cell type could classified into two types. First, degraded secondary wall was formed granular residues in $S_2$ layer and was remained $S_3$ layer and compound middle lamella. Second, the cell wall was slightly degraded and cracked in secondary wall. A gradual thinning of cell wall was occured. The compound middle lamella was separated from secondary wall. The resistance of degradation is increased at vessels, parenchyma, and tracheid and wood fiber in the order named. The type of degradation by species could be classified into four types. Overall degradation type; the degradation of cell wall is usually heavy and the extent of degradation Varies by part of the same sample. Partial degradation type ; this type shows severely different decay type by part of the sample. Nondegraded cells were mixed with degraded cells on the same sample. Erose degradation type ; thinning of the cell wall was occoured and the degradation type was different by part. Slight degradation types ; secondary wall was slightly degraded, cracked and separated from compound middle lamella. Considering different type of burial environment, dry wood was similiar to sound wood and slightly decayed. Waterlogged and peat burial wood was heavilydecayed. Between species of under the same environment, decay type and extent were diferentiated from each other.

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Effect of Varous Physicochemical Factors on the Biodegradation of Explosive 2,4,6-Trinitrotoluene by Stenotropomonas maltophilia (Stenotrophomonas maltophilia에 의한 폭약 2,4,6-Trinitrotoluene의 생분해에 영향을 미치는 물리화학적 요인)

  • 김영진;이명석;조윤석;한현각;김승기;오계헌
    • KSBB Journal
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    • v.14 no.3
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    • pp.315-321
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    • 1999
  • The relationships between the explosive 2,4,6-trinitrotoluene (TNT) degradation by Stenotrophomonas maltophilia and several relevant physicochemical environmental parameters were examined. At neutral pH of the cultures, the degradation of TNT proceeded to completion, whereas only about 50% of TNT was utilized when the cultures were adjusted to acidic pH. The effect of various co-substrates (e.g., glucose, fructose, acetate, citrate, succinate) on the degradation of TNT by the test culture of S. maltophilia was evaluated. The results indicated that, among the various co-substrates studies, the test culture that received 2 mM fructose degraded 100 mg/L of TNT completely within 20 days of incubation at ambient temperature, whereas partial degradation of TNT was observed in the test culture with acetate, citrate, or succinate as a co-substrate, respectively. In fact, fructose was the best co-substrate for TNT degradation in this experiment. The effect of supplemented nitrogens [e.g., (NH$_4$)$_2$,SO$_4$, NH$_4$Cl. urea] on the TNT degradation was monitored. All supplemented nitrogens in this study were inhibitory to TNT degradation. Addition of 1% Tween80 accelerated TNT degradation, and showed complete degradation of TNT within 8 days of incubation. Addition of yeast extract resulted higher growth yields, based on turbidity measurement, but it inhibited TNT degradation.

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Quality of Service Parameters Estimation Model for Adaptive Bandwidth Service in Mobile Cellular Networks (적응형 서비스를 제공하는 이동통신망에서의 서비스 품질 척도 추정 모델)

  • Jung, Sung Hwan;Hong, Jung Wan;Lie, Chang Hoon
    • Journal of Korean Institute of Industrial Engineers
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    • v.33 no.1
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    • pp.153-163
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    • 2007
  • An adaptive framework paradigm where the bandwidth values of the ongoing calls vary according to the trafficsituations is one of the promising concepts for overcoming poor resource conditions due to handoffs in mobilecellular networks. However, quantifying the level of bandwidth degradation of the ongoing calls in an adaptiveframework is important in view of Quality of Service (QoS) Provisioning. Therefore we introduce new QoSparameters, the Degradation Degree Ratio (DDR), which represents the average portion of the degradationdegree during degradation pehod of a call, and the Degradation Area Ratio (DAR), which represents the averageratio of a call's degradation level considering both the period and the degree of degradation jointly in multi-levelbandwidth service. We also develop a new analytical model for estimating the QoS measures such as theDegradation Pehod Ratio (DPR), DDR and DAR. We show how to calculate the QoS measures and illustrate themethod by numerical examples. The proposed model can be used to determine the optimal parameter of theCAC scheme and analyze the sensitivity ofthe QoS parameters in adaptive networks.