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Long-term Reliability (long-term + reliability)
Selected AbstractsLong-term reliability in reporting of childhood pets by adults interviewed twice, 9 years apart.INDOOR AIR, Issue 2 2008Results from the European Community Respiratory Health Survey I First page of article [source] Long-term reliability and observer comparisons in the radiographic diagnosis of periapical diseaseINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2002O. Molven Abstract Aim The aim of this study was to evaluate and compare the long-term diagnostic consistency of two examiners, an endodontist and a radiologist, and to make comparisons with findings recorded by an observer with more recent scientific and clinical experience in endodontics. Methodology Three groups, each consisting of 20 full mouth series of intraoral radiographs, with 79, 93 and 85 endodontically-treated roots, respectively, were successively evaluated for periapical disease. Evaluations were at first performed separately by the three observers. Disagreement and difficult, borderline cases were subjected to joint evaluation. Intra- and interexaminer comparisons were made. For two of the observers the observations were compared with findings recorded several years before for the same cases in the same radiographs. Results The intra- and interobserver long-term reliability of the two original examiners resulted in 83% overall agreement, the kappa values were 0.54, 0.57 and 0.53. Comparisons between all three observers disclosed 82%, 85% and 86% agreement and kappa values 0.55, 0.58 and 0.60. The joint evaluations and decisions did not indicate a dominating influence from any of the observers. Conclusions The long-term reliability of the two original observers was judged as being satisfactory. All three observers judged the overall disease status of the material in the same way. The joint discussions of selected cases might reduce observer variation to an acceptable level, avoid a number of false recordings and increase the reliability and validity of the findings. [source] Fabrication of a Multilayered Low-Temperature Cofired Ceramic Micro-Plasma-Generating DeviceINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2006Amanda Baker Plasma technology is currently being used in innumerable industrial applications. Some of the common uses of this technology include surface cleaning and treatment, sputtering and etching of semiconductor devices, excitation source for chemical analyses, cutting, environmental cleanup, sterilization, and phototherapy. The harsh conditions that these devices must endure require robust refractory materials systems for their fabrication and reliability. Low-temperature cofired ceramic (LTCC) material systems provide a durable and cost-effective platform for the manufacture of such devices, and allow for possible integration into meso-scale microsystems. Our designs are based on RF microstriplines that capacitively couple and ionize small gas discharge sites over the top electrode. In this paper, we have built several iterations of this micro-plasma generating device using LTCC material systems. The impact of electrode ink selection and processing, lamination methods, dielectric layer thickness, and electrode design has been investigated. Several micro-plasma-generating devices were then evaluated for power requirements, output stability, and long-term reliability. [source] Reliability aspects of SiC Schottky diodesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2009Matthias Holz Abstract In recent years, silicon carbide (SiC) high-voltage power devices have gained an ever-increasing market share. The fast development of new device concepts and technologies, e.g. for SiC Schottky diodes, has led to devices with superior switching behaviour, which renders SiC power devices especially favourable for high-frequency applications. As of today, SiC devices enter various fields like, e.g. server power supplies, solar inverters, and drives. These applications pose quite different requirements not only on the electrical properties, but also on the long-term reliability of the devices. In this paper, we describe in detail how Infineon's SiC Schottky diodes excel the reliability requirements. We point out how material properties, device design and packaging technology affect the overall device reliability and how they can be optimized. In addition, we describe measurement results after stress tests that go far beyond standard stress tests according to JEDEC. E.g., we show that SiC devices can safely be operated at high voltage slopes of 120 V/ns. In addition, we show that the use of high performance die attach further improves the device properties and reliability. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] III-V concentrator solar cell reliability prediction based on quantitative LED reliability data,PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 6 2007Manuel Vázquez Abstract III-V Multi Junction (MJ) solar cells based on Light Emitting Diode (LED) technology have been proposed and developed in recent years as a way of producing cost-competitive photovoltaic electricity. As LEDs are similar to solar cells in terms of material, size and power, it is possible to take advantage of the huge technological experience accumulated in the former and apply it to the latter. This paper analyses the most important parameters that affect the operational lifetime of the device (crystalline quality, temperature, current density, humidity and photodegradation), taking into account experience on the reliability of LEDs. Most of these parameters are less stressed for a III-V MJ solar cell working at 1000 suns than for a high-power LED. From this analysis, some recommendations are extracted for improving the long-term reliability of the solar cells. Compared to high-power LEDs based on compound semiconductors, it is possible to achieve operational lifetimes higher than 105,hours (34 years of real-time operation) for III-V high-concentration solar cells. Copyright © 2007 John Wiley & Sons, Ltd. [source] U-Pb Age Determination for Seven Standard Zircons using Inductively Coupled Plasma,Mass Spectrometry Coupled with Frequency Quintupled Nd-YAG (, = 213 nm) Laser Ablation System: Comparison with LA-ICP-MS Zircon Analyses with a NIST Glass Reference MaterialRESOURCE GEOLOGY, Issue 2 2008Yuji Orihashi Abstract This paper evaluates the analytical precision, accuracy and long-term reliability of the U-Pb age data obtained using inductively coupled plasma,mass spectrometry (ICP-MS) with a frequency quintupled Nd-YAG (, = 213nm) laser ablation system. The U-Pb age data for seven standard zircons of various ages, from 28 Ma to 2400 Ma (FCT, SL13, 91500, AS3, FC1, QGNG and PMA7) were obtained with an ablation pit size of 30 ,m diameter. For 207Pb/206Pb ratio measurement, the mean isotopic ratio obtained on National Institute of Standards and Technology (NIST) SRM610 over 4 months was 0.9105 ± 0.0014 (n = 280, 95% confidence), which agrees well with the published value of 0.9096. The time-profile of Pb/U ratios during single spot ablation showed no significant difference in shape from NIST SRM610 and 91500 zircon standards. These results encouraged the use of the glass standard as a calibration standard for the Pb/U ratio determination for zircons with shorter wavelength (, = 213 nm) laser ablation. But 206Pb/238U and 207Pb/235U ages obtained by this method for seven zircon standards are systematically younger than the published U-Pb ages obtained by both isotope dilution,thermal ionization mass spectrometry (ID-TIMS) and sensitive high-resolution ion-microprobe (SHRIMP). Greater discrepancies (3,4% younger ages) were found for the 206Pb/238U ages for SL13, AS3 and 91500 zircons. The origin of the differences could be heterogeneity in Pb/U ratio on SRM610 between the different disks, but a matrix effect accuracy either in the ICP ion source or in the ablation-transport processes of the sample aerosols cannot be neglected. When the 206Pb/238U (= 0.2302) newly defined in the present study is used, the measured 206Pb/238U and 207Pb/235U ages for the seven zircon standards are in good agreement with those from ID-TIMS and SHRIMP within ±2%. This suggests that SRM610 glass standard is suitable for ICP-MS with laser ablation sampling (LA-ICP-MS) zircon analysis, but it is necessary to determine the correction factor for 206Pb/238U by measuring several zircon standards in individual laboratories. [source] VentrAssist Left Ventricular Assist Systems Long-Term In Vitro ReliabilityARTIFICIAL ORGANS, Issue 10 2009Alex Stonehouse Abstract Left ventricular assist systems (LVADs) are typically tested for long-term reliability by using a simulated human cardiovascular system. In this study, 13 VentrAssist (Ventracor Ltd, Chatswood, NSW, Australia) systems are tested in mock loops with the aim of demonstrating in vitro continuous operational reliability of the pump subsystem greater than 80% (60% confidence) over 1 year. As of July 9, 2007, the total time on test of all 13 mock loop pumps is 29.36 years. In vitro reliability of the VentrAssist LVAD blood pump is 96.7% (60% confidence) at 1 year. No failures have been seen over 4.5 years of test, and testing is ongoing. [source] | |||||||||||||