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The rank and anisotropy of anthracites: the indicating surface of reflectivity in uniaxial and biaxial substances
Author(s) -
Hevia V.,
Virgos J. M.
Publication year - 1977
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1977.tb01113.x
Subject(s) - anisotropy , reflectivity , rank (graph theory) , materials science , optics , principal axis theorem , mineralogy , particulates , character (mathematics) , coal , mathematics , physics , geometry , geology , chemistry , combinatorics , organic chemistry
SUMMARY Theoretical and empirical formulae are given which relate the principal reflectivities of uniaxial and biaxial substances to the mean values of random, maximum and minimum reflectivities measured on particulate samples. Instead of using values of R̄ a and R̄ a − R̄ c determined along the principal directions, a method is described for determining respectively: (a) coal rank through the mean random vitrinite reflectivity, and (b) the bireflectance using the difference between the mean random maximum and minimum reflectivities measured on particulate samples, irrespective of uniaxial or biaxial character.