28200 str (129)

( IIAl'I ER III

Anomalous Vlscosltles. Blngham’s Equatlon, Appll-catlons to Palnts, Dentlfrlces, Solls, Ceramlcs, DrlllJng Muds, Tale, etc.

liii' industrial chemist deals very frequeijtJy willi materials which are not true fiuids, and which therefore show anomalous viscosities. The laws ot dólormalkm tur sucli inaterials lie between those applicable to lluids and solids. When the materiał in question is approxiinately liquid, and when the yiscosities can be conveniently measured, it is best to try lo modify Newton's assumption and, in the specjał case of capillary flow, I^Joiseuille's law. Trouton, and Trouton and Andrews, as early as 1904-1906, iuyestigated the relationship betweea Inter a ud thr ratę o i elongation of cylinders I pilch, a very viscous hquid, and found that the I viseosi(y was not COnstant, PLottujg flow-ratę I agaiiist lóudititf stress, i heir eurves are linear over I rifl bul u Iow stresu rangi, ihe straigbt linę, whet I eetiupojated, y/yes a smali intercept on the ęfeess mej*, I milion deser ihec the ratio of loadiog fta I || lale 0/ nhf.ur as the " ooeffi/dent of vifC0OE I harf jon." Thin is not fhe sarnę as viv/Aitv, ffaff: I looduif; 01 trinih: '.Utg not. the *arae iMfjg at I !§|learing strgfi, Therc bas becn much mć.owfef' I •tandlng a» to Mg meaning of thh coefftdect I 'hii^liam linds fimilar curves for many materii I When Ihcy ;u e forced through capillary tubes.

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