Lifetime Estimation Method Research Articles

P‐92: Rapid and Non‐destructive Lifetime Estimation Method for LED Backlight Displays

AbstractIn this paper we will display a new method for measuring the temperature of a LED backlight display. Generally the LED junction temperature (Tj) is the key factor for lifetime estimation and it can be measured by the forward voltage variation when the LED is turned on under small driving current. Unfortunately the forward voltage measurement is a destructive and non‐direct method for the display and we can get only a few LED information. We found that by recording the Wp (peak wavelength) of the display spectrum, a non‐destructive LED backlight display lifetime evaluation method can be developed. By also, the lifetime of the display can be calculated simply.

Lifetime Evaluation of Oil-immersed Power Capacitor using Conversion Factor between Model Sample and Practical Equipment

In this paper, the lifetime estimation method was discussed in view of Weibull distribution. For the case of power capacitor, the conversion factor between model specimen and practical equipment can be calculated by using the ratio of the electrode edge length of them and the Weibull shape parameter of the normalized V-t data obtained from the model samples. The actual failure rate of the power capacitor with PP film/capacitor-paper composite dielectric system was found to agree well with the estimated failure rate from the model samples.

Mechanical Reliability(Life-Time) Estimation for 25.8kV Eco Solid Insulated Switchgear

In this paper, mechanical reliability(Life-time) estimation method for 25.8kV SIS(Solid Insulated Switchgear) has been studied. Recently enacted KEPCO's standard includes clause that have to submit a warrantable reliability data for life-time(over B10 25 years) of an epoxy-solid insulating material. Accordingly, this research was carried out on the ALT(Accelerated Life Test) and Life-Estimation method for SIS's insulating material. Mechanical life-time estimation for SIS's insulating material is to verify reliability for tensile creep & fatigue stress, which is the major mechanical stress of SIS. This study proved that SIS's reliability for mechanical stress and established that confidence for estimation results in further verification test.

Analysis of polymer electrolyte fuel cell performance by electrode polarization model

Abstract For development of polymer electrolyte fuel cell (PEFC) lifetime estimation method, a high accuracy PEFC electrode polarization model is required. An electrode polarization model which was previously proposed was verified. However, accuracy of the electrode polarization model was not enough to estimate PEFC performance under various conditions. A new high accuracy PEFC electrode polarization model has been developed based on electrochemical consideration and data observed at elevated pressures. In the cathode polarization model, effects of O 2 diffusion and H 2 O plugging have to be considered to obtain high accuracy for long-term operation. In addition, PEFC performance degradation was analyzed by the electrode polarization model. Main factors of PEFC performance degradation are OCV drop, the cathodic activation polarization, voltage drops by O 2 diffusion and H 2 O plugging.

Estimating the depth and lifetime of a fluorescent inclusion in a turbid medium using a simple time-domain optical method

A simple time-domain optical method for estimating the depth (d) and lifetime (tau) of fluorescent inclusions in a turbid medium is described. We demonstrate the method for depth and lifetime estimation of a fluorescent inclusion directly by fitting a monoexponential decay (tau(eff)) of the temporal position of the temporal point-spread function and the measurement of its maximum temporal position (t(max)). Since both of these measurements are intensity independent, this method provides a robust and efficient approach. This method is validated with experimental data.

A New Approach for Estimating the Life Expectancy of Optical Disk for Digital Archival Storage

In this study, we examine a lifetime estimation method for optical disks using the Eyring acceleration model and statistical analysis. The standardized life expectancy of an optical disk is defined as its minimum lifetime at a 95% survival probability and a 95% confidence level under disk conditions in terms of its degree of usage. We confirmed the capability of this method of estimating life expectancy by considering the stresses of temperature and relative humidity, and providing a confidence level.

高経年GISにおけるOリングの劣化特性

Owing to increasing number of highly aged GIS, the investigation of the remaining lifetimes of those systems are becoming more important. Because a lot of O-rings are used in GIS, the study of degradation mechanism and lifetime estimation method of O-ring is essential. In this paper, the information about O-ring degradation mechanism is described, and the statistical method for estimating the remaining lifetime of O-ring is proposed. The degradation of O-ring is mainly subject to chemical reactions triggered by oxygen. Because there are many factors influencing those chemical reactions, the dispersion of degradation rates of O-rings in GIS is very large. Consequently the statistical analysis is one of the effective techniques for lifetime estimation of O-rings in GIS.

Accelerated ageing test procedures for selective absorber coatings including lifetime estimation and comparison with outdoor test results

The possibilities and problems of durability tests of solar absorber coatings are discussed with respect to service lifetime estimation methods. Constant temperature tests in air as well as humidity and condensation tests have been carried out at different load levels on six commercially available solar absorber coatings (black chrome, black nickel, coloured stainless steel and nickel pigmented anodized aluminium). The results of the temperature tests have been used for a lifetime estimation based on Arrhenius relations. The estimated degradation behaviour and the changes of the spectral reflectance of the coatings after the accelerated indoor tests are compared with the results of outdoor tests under stagnation conditions. In this way, the influence and the importance of the particular degradation factors (temperature, humidity, pollutants, etc.), the specific sensitivity or stability of the tested coatings with respect to these degradation factors, and the applicability of the lifetime estimation method have been investigated.

A Method to Estimate the Lifetime of Solid Electrical Insulation

This paper describes a new statistical method of lifetime estimation of a solid electrical insulation using data from an accelerated aging test. The method simultaneously uses the maximum likelihood estimation and the Newton-Raphson methods. The novel aspect of this work is the introduction of a new threshold term in addition to well-known estimation techniques based on the inverse power model combined with the Weibull distribution. Thus, we can estimate the threshold value with a confidence interval. In order to reduce time and costs of voltage-lifetime test5, an accelerated testing procedure with type I censoring is considered.

長時間Ｖ‐ｔ特性における最適数学モデル選定と寿命推定の統計的方法

長時間Ｖ‐ｔ特性における最適数学モデル選定と寿命推定の統計的方法