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Official Journal of the Japan Wood Research Society

Table 4 Results of measurements of mean hardness values for sample C of beech wood

From: An attempt to unify the Brinell, Janka and Monnin hardness of wood on the basis of Meyer law

Beech 782 kg/m3

Sample C (h 9%)

Hardness measures (mean value ± standard error) (MPa)

Spherical (ball)

Cylindrical

Indenter diameter

D (mm)

New measure

HKb

Brinell

HB

New measure

HKc

Brinell type

HBc

10

44.0 ± 1.5

44.1 ± 1.3

45.2 ± 1.1

46.8 ± 2.4

15

41.3 ± 0.7

42.5 ± 1.2

42.7 ± 1.1

42.7 ± 1.2

30

42.5 ± 1.0

42.2 ± 1.9

42.8 ± 0.6

37.2 ± 1.8

Arithmetic mean

42.6 ± 1.4*

42.9 ± 1.0*

43.6 ± 1.4*

42.2 ± 4.8*

Average means

42.83 ± 0.57*

  1. *Standard deviation of the type sm−1 for m = 3 or m = 4 without the t-Student factor, but also without divisor \(\sqrt m\) for the standard error of the mean value.