• Title/Summary/Keyword: useful life-time

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Stochastic modelling fatigue crack evolution and optimum maintenance strategy for composite blades of wind turbines

  • Chen, Hua-Peng;Zhang, Chi;Huang, Tian-Li
    • Structural Engineering and Mechanics
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    • v.63 no.6
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    • pp.703-712
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    • 2017
  • The composite blades of offshore wind turbines accumulate structural damage such as fatigue cracking due to harsh operation environments during their service time, leading to premature structural failures. This paper investigates various fatigue crack models for reproducing crack development in composite blades and proposes a stochastic approach to predict fatigue crack evolution and to analyse failure probability for the composite blades. Three typical fatigue models for the propagation of fatigue cracks, i.e., Miner model, Paris model and Reifsnider model, are discussed to reproduce the fatigue crack evolution in composite blades subjected to cyclical loadings. The lifetime probability of fatigue failure of the composite blades is estimated by stochastic deterioration modelling such as gamma process. Based on time-dependent reliability analysis and lifecycle cost analysis, an optimised maintenance policy is determined to make the optimal decision for the composite blades during the service time. A numerical example is employed to investigate the effectiveness of predicting fatigue crack growth, estimating the probability of fatigue failure and evaluating an optimal maintenance policy. The results from the numerical study show that the stochastic gamma process together with the proper fatigue models can provide a useful tool for remaining useful life predictions and optimum maintenance strategies of the composite blades of offshore wind turbines.

Event-specific Detection Methods for Genetically Modified Maize MIR604 Using Real-time PCR

  • Kim, Jae-Hwan;Kim, Hae-Yeong
    • Food Science and Biotechnology
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    • v.18 no.5
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    • pp.1118-1123
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    • 2009
  • Event-specific real-time polymerase chain reaction (PCR) detection method for genetically modified (GM) maize MIR604 was developed based on integration junction sequences between the host plant genome and the integrated transgene. In this study, 2 primer pairs and probes were designed for specific amplification of 100 and 111 bp DNA fragments from the zSSIIb gene (the maize endogenous reference gene) and MIR604. The quantitative method was validated using 3 certified reference materials (CRMs) with levels of 0.1, 1, and 10% MIR604. The method was also assayed with 14 different plants and other GM maize. No amplification signal was observed in real-time PCR assays with any of the species tested other than MIR604 maize. As a result, the bias from the true value and the relative deviation for MIR604 was within the range from 0 to 9%. Precision, expressed as relative standard deviation (RSD), varied from 2.7 to 10% for MIR604. Limits of detections (LODs) of qualitative and quantitative methods were all 0.1%. These results indicated that the event-specific quantitative PCR detection system for MIR604 is accurate and useful.

On Improving the Object-Oriented Method for Real-Time System by Applying the SE Process (SE프로세스를 통한 객체지향 실시간시스템 개발 방법론의 개선에 관한 연구)

  • Lee, Byoung Gil;Lee, Jae Chon
    • Journal of the Korean Society of Systems Engineering
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    • v.2 no.2
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    • pp.21-26
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    • 2006
  • In modern systems technology, increasingly more systems are anticipated to operate in real-time environment. These systems are usually complex to implement since it is not easy to satisfy the real-time requirement for both hardware and software components simultaneously. In this paper, we first review an object-oriented development process that was proposed earlier for software-intensive real-time system using the Unified Modeling Language (UML). We then study how to improve the problems that the UML approach might have. Applying the systems engineering(SE) process yields useful results which include : 1) an improved requirements management over the whole system life-cycle ; 2) a detailed scenario on how to carry out the SE process ; and 3) a conversion process from the text-based requirements to the UML-based graphic ones.

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New Accelerated Life Test Plans for Weibull and Lognormal Lifetime Distributions (와이블과 대수정규 수명분포를 따를 때 새로운 가속수명시험 계획의 개발)

  • Seo, Sun-Keun
    • Journal of Applied Reliability
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    • v.14 no.3
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    • pp.182-190
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    • 2014
  • This paper presents new practical accelerated life test plans with different censoring times at three levels of stress for Weibull and lognormal lifetime distributions, respectively. The proposed plans are compared with the corresponding two-level statistically optimal plans and three-level compromise and practical plans. Computational results indicate that new practical plans have been more precise and effective than the existing three-level plans under a constraint of total testing time. In addition, a procedure to determine useful ALT plans is illustrated with a numerical example.

A Study on the Internet and Teenagers' Culture

  • Jang, Jung-Min;Cho, Hyun-Soo;Jung, Hye-Jung
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.3
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    • pp.511-523
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    • 2003
  • Internet has become an important part of teenagers' life and has changed the life style of teenagers. Internet can be an useful tool for educating teenagers and also can be misused as a cyberspace for social problems. Recognizing that teenagers spend most of their free time enjoying internet and they form their own new life culture, it is needed to develop practical strategies for maximizing the positive effect of internet on the teenagers' culture. The purpose of this research is to suggest a desirable way for forming teenagers' healthy internet-based culture. The research was conducted by the survey of teenagers in the city of Pyongtaek on their use of internet and their problems The survey shows that most of teenagers are using internet in order to release the stress and most of them are hooked on it. It also indicates that cyber police and volunteer groups should be formed to help the desirable teenagers' internet-based culture.

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Review of the coronary artery disease in terms of insurance medicine (관상동맥질환의 보험의학적 이해)

  • Lee, Sinhyung
    • The Journal of the Korean life insurance medical association
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    • v.32 no.2
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    • pp.33-38
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    • 2013
  • Coronary artery diseases are very important agenda in the insurance medicine. Insurance medicine is defined as using medical knowledge for insurance administration such as underwriting, claims, and customer satisfaction. This review article contains review of coronary artery disease in terms of insurance medicine. Estimation of extra-risks for acute myocardial infarction are MR of 349% and EDR of 41‰. In medical underwriting, individual life applicants can be assessed by Framingham's CHD risk assessment model. In claims, medical claims review is a useful method of consulting for claims staffs. Several diagnostic criteria of acute myocardial infarction are introduced in time. The universal definition of myocardial infarction by ESC/ACCF/WHF was demonstrated the most valuable predictor of 10-year mortality. Contents for State-Of-The-Art of the coronary artery disease are current antithrombotics. There are many novel anti-thrombotic agents such as ticagrelol, dabigatran, rivaroxaban, and pegnivacogin.

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SSR-Primer Generator: A Tool for Finding Simple Sequence Repeats and Designing SSR-Primers

  • Hong, Chang-Pyo;Choi, Su-Ryun;Lim, Yong-Pyo
    • Genomics & Informatics
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    • v.9 no.4
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    • pp.189-193
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    • 2011
  • Simple sequence repeats (SSRs) are ubiquitous short tandem duplications found within eukaryotic genomes. Their length variability and abundance throughout the genome has led them to be widely used as molecular markers for crop-breeding programs, facilitating the use of marker-assisted selection as well as estimation of genetic population structure. Here, we report a software application, "SSR-Primer Generator " for SSR discovery, SSR-primer design, and homology-based search of in silico amplicons from a DNA sequence dataset. On submission of multiple FASTA-format DNA sequences, those analyses are batch processed in a Java runtime environment (JRE) platform, in a pipeline, and the resulting data are visualized in HTML tabular format. This application will be a useful tool for reducing the time and costs associated with the development and application of SSR markers.

Isolation of the Arabidopsis Phosphoproteome Using a Biotin-tagging Approach

  • Kwon, Sun Jae;Choi, Eun Young;Seo, Jong Bok;Park, Ohkmae K.
    • Molecules and Cells
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    • v.24 no.2
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    • pp.268-275
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    • 2007
  • Protein phosphorylation plays a key role in signal transduction in cells. Since phosphoproteins are present in low abundance, enrichment methods are required for their purification and analysis. Chemical derivatization strategies have been devised for enriching phosphoproteins and phosphopeptides. In this report, we employed a strategy that replaces the phosphate moieties on serine and threonine residues with a biotin-containing tag via a series of chemical reactions. Ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO)-depleted protein extracts prepared from Arabidopsis seedlings were chemically modified for 'biotin-tagging'. The biotinylated (previously phosphorylated) proteins were then selectively isolated by avidin-biotin affinity chromatography, followed by two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). This led to the identification of 31 protein spots, representing 18 different proteins, which are implicated in a variety of cellular processes. Despite its current technical limitations, with further improvements in tools and techniques this strategy may be developed into a useful approach.

Proteome analysis: Salmoenlla enteritidis antigen proteins (Proteomics 기법을 이용한 Salmonella enteritidis의 항원 단백질 분석)

  • Park, Mi-rim;Shin, Yong-seung;Han, Dae-yong;Kim, Yong-hwan;Jung, Tae-sung;Lee, Hu-Jang;Lee, Eung-Goo;Kim, Jong-su;Kim, Eun-hee;Kim, Gon-Sup
    • Korean Journal of Veterinary Research
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    • v.44 no.1
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    • pp.57-64
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    • 2004
  • The common pathogen Salmonella enteirtidis (S. enteritidis) is the major cause of foodborne disease. Protein identification by peptide mass fingerprinting using the matrix-assisted laser desorption ionization time of fight (MALDI-TOF) mass spectrometry (MS) can analysis unambiguously identity the spots from 2-dimensional electrophoresis (2-DE) gel. In this report, we examined protein components from patterns of S. enteritidis proteins. In addition, antigens that are recognized by sera can be identified by immunoblotting. This study that 2-DE analysis of S. enteritidis yields useful information concerning S. enteritidis proteome, the results that have been obtained led to a more detailed understanding of Salmonella pathology and open further interesting fields for future work.

Molecular discrimination of Panax ginseng cultivar K-1 using pathogenesis-related protein 5 gene

  • Wang, Hongtao;Xu, Fengjiao;Wang, Xinqi;Kwon, Woo-Saeng;Yang, Deok-Chun
    • Journal of Ginseng Research
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    • v.43 no.3
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    • pp.482-487
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    • 2019
  • Background: The mixed-cultivation of different Panax ginseng cultivars can cause adverse effects on stability of yield and quality. K-1 is a superior cultivar with good root shape and stronger disease resistance. DNA markers mined from functional genes are clearly desirable for K-1, as they may associate with major traits and can be used for marker-assisted selection to maintain the high quality of Korean ginseng. Methods: Five genes encoding pathogenesis-related (PR) proteins of P. ginseng were amplified and compared for polymorphism mining. Primary, secondary, and tertiary structures of PR5 protein were analyzed by ExPASy-ProtParam, PSSpred, and I-TASSER methods, respectively. A coding single nucleotide polymorphism (SNP)-based specific primer was designed for K-1 by introducing a destabilizing mismatch within the 3' end. Allele-specific polymerase chain reaction (PCR) and real-time allele-specific PCR assays were conducted for molecular discrimination of K-1 from other cultivars and landraces. Results: A coding SNP leading to the modification of amino acid residue from aspartic acid to asparagine was exploited in PR5 gene of K-1 cultivar. Bioinformatics analysis showed that the modification of amino acid residue changed the secondary and tertiary structures of the PR5 protein. Primer KSR was designed for specific discrimination of K-1 from other ginseng cultivars and landraces. The developed real-time allele-specific PCR assay enabled easier automation and accurate genotyping of K-1 from a large number of ginseng samples. Conclusion: The SNP marker and the developed real-time allele-specific PCR assay will be useful not only for marker-assisted selection of K-1 cultivar but also for quality control in breeding and seed programs of P. ginseng.