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Aging Properties (aging + property)

Distribution by Scientific Domains
Polymers and Materials Science50%

Selected Abstracts

On the weak IFR aging of bivariate lifetime distributions

APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 3 2005
Maxim Finkelstein
Abstract A new notion of bivariate aging in a competitive risk framework is introduced. Aging properties of bivariate distributions are defined by aging properties of a series system with possibly dependent components. A case of exponential marginals is considered. Sufficient conditions for a weak IFR aging (weak DFR negative aging) are derived and a number of simple examples are considered. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Aging properties of the residual life length of k -out-of- n systems with independent but non-identical components

APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2004
Xiaohu Li
Abstract The k -out-of- n structure is a very popular type of redundancy in fault-tolerant systems, it has founded wide applications in industrial and military systems during the past several decades. This paper will investigate the residual life length of a k -out-of- n system with independent (not necessarily identical) components, given that the (n,k)th failure has occurred at time t,0. Behaviour of PF2, IFR, DRHR, DMRL, NBU(2) and NBUC classes of life distributions are derived in terms of the monotonicity of the residual life given the time of the (n,k)th failure. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Effect of ATH content on electrical and aging properties of EVA and silicone rubber blends for high voltage insulator compound

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007
M. A. Pradeep
Abstract The effect of trihydrated alumina (Al2O3, 3H2O) (ATH) filler in ethylene-vinyl acetate copolymer (EVA) and silicone rubber blends was investigated by performing a series of laboratory experiments to simulate different natural aging conditions. Samples with varying ATH content in a 50-50 blend of EVA and polydimethylsiloxane (PDMS) (silicone rubber, MQ) were tested to investigate the tracking resistance, resistance to UV radiation, corona, heat, and water immersion. Changes in surface resistivity, volume resistivity, and hydrophobic characteristics were evaluated for different compounds having ATH content. These exercises were mainly carried out to optimize the filler level. In immersed condition the water absorption increases with ATH content. The recovery of hydrophobicity, after aging by heat, is appreciable at higher ATH levels, than at lower ATH levels. The tracking and erosion resistance decrease as ATH content increases. When compounds containing different ATH content were subjected to corona treatment, the samples with higher ATH levels exhibited better results. All samples changed their color to a darker shade and there was an increase in the hydrophobicity, when subjected to UV radiation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3505,3516, 2007 [source]

Effect of montmorillonite on properties of styrene,butadiene,styrene copolymer modified bitumen

POLYMER ENGINEERING & SCIENCE, Issue 9 2007
Jianying Yu
Clay/styrene,butadiene,styrene (SBS) modified bitumen composites were prepared by melt blending with different contents of sodium montmorillonite (Na-MMT) and organophilic montmorillonite (OMMT). The structures of clay/SBS modified bitumen composites were characterized by XRD. The XRD results showed that Na-MMT/SBS modified bitumen composites may form an intercalated structure, whereas the OMMT/SBS modified bitumen composites may form an exfoliated structure. Effects of MMT on physical properties, dynamic rheological behaviors, and aging properties of SBS modified bitumen were investigated. The addition of Na-MMT and OMMT increases both the softening point and viscosity of SBS modified bitumens and the clay/SBS modified bitumens exhibited higher complex modulus, lower phase angle. The high-temperature storage stability can also be improved by clay with a proper amount added. Furthermore, clay/SBS modified bitumen composites showed better resistance to aging than SBS modified bitumen, which was ascribed to barrier of the intercalated or exfoliated structure to oxygen, reducing efficiently the oxidation of bitumen, and the degradation of SBS. POLYM. ENG. SCI., 47:1289,1295, 2007. © 2007 Society of Plastics Engineers [source]