Hygroscopic crust

The work by Boyer [50] was concerned with mullite refractories utilized in blast-furnace applications. The major reaction appeared to be K2C03 fluxing of the mullite-glass samples to form minor kaliophilite. Boyer described the reaction as a soft black hygroscopic crust confined to the... 

They act as proton donors and also have a hygroscopic (desiccating) action due to their avidity for water. The protective keratin layer of the skin is breached and coagulative necrosis occurs in the tissues with thrombosis of vessels. Proteins are precipitated with often liberation of heat (exothermic reaction) which adds to destrnction with formation of a crust stopping penetration of acid into the tissues. According to the acid, the scab on the skin will differ from brownish black scab for snlfnric acid (Fig. 4.55), yellow-brownish discoloration with hydrochloric acid, and an orange yellow dne to nitric acid [20] (Fig. 4.56). Assessment of the lesion depth is often difficult). 

Osmotic potentials of -84 to -115 atm, induced predominantly by salt incrustation (Follmann, 1967), do not drastically decrease the vitality of coastal lichens in Chile. In fact, these coastal lichens may profit by the hygroscopic nature of their salt crust. Until recently there have not been any studies on the effect of salt on water uptake and photosynthesis of lichens. Siegel and Daly (1968) found that the respiration of Cladonia rangi-ferina was unaffected by a 1 TV KCl solution and even showed some reactivation after being immersed in saturated LiCl solution (osmotic potential about -1000 atm). 

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