Accelerated aging procedure

Accelerated stability tests using the emulsion volume index (EVI) Accelerated aging procedure in which an emulsion in a microhematocrit tube is subjected to centrifugal force EVI = (length of emulsion phase/lolul length of column) (% fal/0.9) x 100. A higher EVI indicates a more stable emulsion under the conditions of the test. 

Alkaline-deaddifying-agent effect on naturally aged cellulosic textiles abrasion resistance of fabrics, 151,152r,153,154f accelerated aging procedure, 146 aqueous-extract pH of fabrics, 149,150r,151... 

M. E Rocha, A. A. P. Mansur, and H. S. Mansur. FTIR investigation of UHMWPE oxidation submitted to accelerated aging procedure. Macroniolecular Symposia, 296 (1), 487-492 (2010). 

The most common test used to study the oxidation resistance of mbber compounds involves the accelerated aging of tensile dumbbell samples in an oxygen-containing atmosphere. Brown et al. [22] recently reviewed long-term and accelerated aging test procedures. The ASTM practices (D 454 (09.01) D 865 (09.01) D 2000 (09.01, 09.02) D3137 (09.01) D 572 (09.01) D 3676 (09.02) D 380 (09.02)) for these tests clearly state that they are accelerated tests and should be used for relative comparisons of various compounds and that the tests may not correlate to actual long-term... 

In the laboratory aging procedure (Johnson and Korcek, 1991), high temperature antioxidant capabilities were assessed at 160°C in a batch reactor using blow by components to accelerate oil degradation. The sample analyzed after five hours of accelerated aging of (MoDTC + ZDDP) without MPH, had lost its ability to reduce friction coefficient to below that which would be observed for a ZDDP - only system. The five hour sample from the mixture (MoDTC + ZDDP) containing added MPH still provided substantial friction reduction and the results are very similar to those observed for the fresh mixtures, p 0.05. 

A systematic investigation of intrinsic chemical stability was carried out on devices specially designed for high power applications [7]. For this purpose, accelerated ageing test procedures were developed for nc-DSCs and it turned out that, to first order, a separation can be made between the effects of visible light soaking, UV illumination and thermal treatment on long term stability. 

Environmental Tests. It is desirable to know the rate at which an adhesive bond will lose strength due to environmental factors in service. Strength values determined by short-term tests do not give an adequate indication of an adhesive s performance during continuous environmental exposure. Laboratory-controlled aging tests seldom last longer than a few thousand hours. To predict the permanence of an adhesive over a 20-year product life requires accelerated test procedures and extrapolation of data. Such extrapolations are extremely risky because the causes of adhesive bond deterioration are complex (see Sec. 15.2.2). Unfortunately no universal method has yet been established to estimate bond life accurately from short-term aging data. 

Several investigators have studied the effects of deacidification on paper. Flieder (7) evaluated several deacidification procedures using breaking length, fold, burst, tear, reflectance, opacity, pH, copper number, and ash as criteria of change. Accelerated aging for 72 h at 105 °C and for 4 h at 87°C and 60% relative humidity was employed as measures... 

In reviewing the literature on the effect of deacidification on paper, three important factors emerge (a) it is desirable to work with papers that are reproducible, well characterized, and similar in properties, both chemical and physical, to old papers (b) much more work needs to be done on the interaction of metals with the carboxyls in cellulose and (c) a standard procedure for accelerated aging that includes some moisture in the aging atmosphere is desperately needed. 

The series of observations outlined above have a number of implications for any program directed at preserving the quality of cellulosic materials. These can be categorized broadly as relating to three types of objectives (1) prevention of further deterioration, (2) recovery of some of the properties already lost through aging, and (3) the interpretation of accelerated testing procedures. 

Aging Procedures. All treated and/or washed samples were air dried and conditioned at 70 °F and 50% rh before being subjected to accelerated aging in humid (90 °C and 50% rh) or dry (100 °C) circulating-air ovens for 1, 2, 3, and 5 weeks. Prior to testing, the oven-aged samples were again conditioned at 70 °F and 50% rh. 

This section describes a methodical procedure that allows reliability issues to be approached efficiently. MEMS reveal specific reliability aspects, which differ considerably from the reliability issues of integrated circuits and macroscopic devices. A classification of typical MEMS-failure modes is given, as well as an overview of lifetime distribution models. The extraction of reliability parameters is a Tack of failures situation using accelerated aging and suitable models. In a case study, the implementation of the methodology is illustrated with a real-fife example of dynamic mechanical stress on a thin membrane in a hot-film mass-airflow sensor. 

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