This definition appears very frequently
The first condition requires the equipment to be in thermal equilibrium with the elevated temperature conditions of the test. The second condition requires that the aging regime at the tested temperature is the same or sufficiently similar to the aging regime at the extrapolated temperature to provide a valid result. For example, at high temperatures, melting or annealing may dominate aging, but at lower temperatures aging may take the form of embrittlement. Thus, the second condition requires a careful consideration of the component material transition temperatures. This paper will report on an effective approach developed for performing post-accident operating time extrapolations.