Long-Term Isothermal Aging Effects on Carbon Fabric-Reinforced PMR-15 Composites: Compression Strength

The design lifetime (30 years) of Ukrainian NPPs has already been expired or will be expired soon. One of the priority areas for the development of nuclear energy is long-term operation (LTO) based on the results of periodic safety review. At present, eleven Ukrainian NPP units are operated under LTO conditions, which in turn causes certain features of operation related to wear, fatigue and general aging of components and structures. An issue of aging management is considered one of the main factors to ensure the safety of a nuclear installation, both in the design lifetime and in the long-term operation. The primary purpose of aging management is to ensure the safety and maximum efficiency of operation through the implementation of technically and economically feasible measures aimed at timely detection and keeping of degradation of NPP components caused by aging within the limits. One way to determine the efficiency of implemented measures and aging management programs is to analyze operational experience and, in particular, analyze the number of NPP operational occurrences during the design and long-term operation period and that are directly related to the aging effects. This paper presents the results of the analysis of the events at Ukrainian NPPs caused by aging processes, compares the results of national and international experience.

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Atmospheric and Long-term Aging Effects on the Electrical Properties of Variable Thickness WSe2 Transistors

ACS Applied Materials & Interfaces ◽

10.1021/acsami.8b12545 ◽

2018 ◽

Vol 10 (42) ◽

pp. 36540-36548 ◽

Cited By ~ 10

Author(s):

Anna N. Hoffman ◽

Michael G. Stanford ◽

Cheng Zhang ◽

Ilia N. Ivanov ◽

Akinola D. Oyedele ◽

...

Keyword(s):

Electrical Properties ◽

Variable Thickness ◽

Aging Effects

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EXPERIMENTAL INVESTIGATION OF THE DURABILITY OF LOAD BEARING TIMBER-GLASS COMPOSITES UNDER THE EFFECTS OF ACCELERATED AGING

Journal of Green Building ◽

10.3992/1943-4618.14.2.45 ◽

2019 ◽

Vol 14 (2) ◽

pp. 45-59 ◽

Cited By ~ 2

Author(s):

Halet Almila Arda Buyuktaskin ◽

Mehmet Serkan Yatagan ◽

Gulseren Erol Soyoz ◽

Leyla Tanacan ◽

Morvarid Dilmaghani

Keyword(s):

Raw Materials ◽

Accelerated Aging ◽

Structural Elements ◽

Atmospheric Conditions ◽

Aging Effects ◽

Glass Composite ◽

Load Bearing ◽

Glass Composites ◽

Before And After

Although timber was used extensively as a structural material for traditional buildings in Turkey in the past, usage of structural timber decreased significantly over time and timber has been largely replaced by other materials. As timber is a natural, durable and sustainable material, it would be desirable to re-introduce timber structural elements to contemporary construction in a form that is appealing to industry. Timber-glass composite structural elements are potentially a good candidate for this purpose. To that end, a series of tests were conducted on load-bearing timber-glass composites in order to understand the long–term structural performance of the composite material under atmospheric conditions; to decrease the recurring cost of repair and maintenance; and to minimize the exhaustion of raw materials and energy. In this paper, the first part of this experimental work is presented, which focuses on the durability of timber-glass composite under the effects of accelerated aging, carried out on small-sized timber-glass composite specimens. Accelerated aging effects were observed under wetting-drying, freezing-thawing, UV effects, resistance to acids and high temperature. The mechanical strength of the timber-glass composite specimens before and after the effect of accelerated aging was measured by adhesion and shear strength tests and a comparative analysis of the results was carried out. The results of the experiments indicate that timber-glass composite is suitable to be used under protection from environmental conditions.

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Impact of isothermal aging on fine pitch BGA packages with Sn-Ag-Cu solder interconnects

International Symposium on Microelectronics ◽

10.4071/isom-2010-tp4-paper3 ◽

2010 ◽

Vol 2010 (1) ◽

pp. 000298-000305

Author(s):

Tae-Kyu Lee ◽

Weidong Xie ◽

Thomas R. Bieler ◽

Kuo-Chuan Liu ◽

Jie Xue

Keyword(s):

Thermal Cycling ◽

Microstructure Evolution ◽

Isothermal Aging ◽

Substrate Surface ◽

Solder Interconnects ◽

Surface Finishes ◽

Bga Packages ◽

Fine Pitch ◽

Solder Balls

The interaction between isothermal aging and long-term reliability of fine pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt%) solder ball interconnects are investigated. In this study, 0.4mm fine pitch packages with 0.3mm diameter Sn-Ag-Cu solder balls are used. Two different die sizes and two different package substrate surface finishes are selected to compare the internal strain impact and alloy effect, especially the Ni effect during thermal cycling. To see the thermal impact on the thermal performance and long-term reliability, the samples are isothermally aged and thermal cycled from 0 to 100°C with a 10minute dwell time. Based on weibull plots for each aging condition, the lifetime of the package reduced approximately 44% with 150°C aging precondition. The microstructure evolution is observed during thermal aging and thermal cycling with different phase microstructure transformations between electrolytic Ni/Au and OSP surface finishes, focusing on the microstructure evolution near the package side interface. Different mechanisms after aging at various conditions are observed, and their impacts on the fatigue life of solder joints are discussed.

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