Degradation operational phenomena

Systems (4) and (5) have been applied successfully to potentiate human interferon production in diploid cell cultures in vitro 143 146). Superinduction may also be operative in vivo22,59. Whether priming is operative in vivo, has not been assessed yet. The superinduction phenomenon will be discussed below. Neither superinduction nor priming153 appear to act through increasing the resistance of poly(I) poly(C) to nucleolytic degradation. 

Non-oxide CMCs are susceptible to degradation by oxidation embrittlement that operates at intermediate temperatures, between 500 and 900°C. This is referred to as pest phenomenon by a few authors. The matrix cracks created upon loading become pathways for the ingress of oxygen into the material. The pyrocarbon interphase is consumed (oxygen reacts to form gaseous products) and the SiC fibers are degraded by oxidation,... 

Could a similar phenomenon occur in the melt Were thermotropic polymers possible They were possible, and indeed the number reported to date by academic and industrial researchers is nearly beyond count. In addition, as it later turned out, aromatic thermotropic polymers were found to offer a great many more useful properties than just their now well-known tensile capabilities. These polymers are injection moldable, albeit at temperatures in the vicinity of 400° C, a temperature not compatible with common melt-spinning equipment. The rate of thermal degradation of such a polyester at 400° C makes stable fiber production particularly difficult. Moreover, most conventional injection-molding equipment requires modification to operate at the high temperatures needed to ensure reasonable processing of this polymer. 

In the introduction, it is mentioned that the use of carbon-based catalyst support materials leads to major degradation mechanisms, which are occurring during fuel cell operation. The most common known and well-understood phenomenon is carbon corrosion. According to (15.1), carbon gets oxidized with water to CO2 [17]. 

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