Engineering Properties of Biomass - Engineering and Science of Biomass Feedstock Production and Provision - page 30

Fig. 2.4 Physical appearance of steam-exploded particles treated at different steam explosion
conditions. From left to right : ( a ) untreated Douglas Fir; ( b ) 200°C, 5 min; ( c ) 200°C, 10 min;
( d ) 220°C, 5 min; ( e ) 220°C, 10 min. Reprinted with permission from Lam PS, Sokhansanj S, Bi
XT, and Lim CJ.2012. Colorimetry applied to steam-treated biomass and pellets made from
western Douglas fir ( Pseudotsuga menziesii L.). Transactions of the ASABE 55(2): 673-678.
St. Joseph, Mich.: ASABE

Table 2.4 Multi-linear regression equations (MLR) between color parameters, chemical
composition, and elemental composition ( α = 0.01, number of replications = 2) a

Equation parameters
Intercept

Dependent variable L * a * b * R 2 F -Value p -Value

Elemental analysis with color
parameter

C 12.1038 1.2117 7.2308 −4.0882 0.97 261.06 <0.0001

H 0.0709 0.2654 1.602 −0.911 0.99 1093.07 <0.0001

O −0.8498 0.0633 0.3755 −0.212 0.97 258.9 <0.0001

Chemical composition with color
parameters
Lignin −252.71 8.5533 48.5518 −27.0467 0.97 210.67 <0.0001
Extractives 48.244 −0.6582 −3.7874 1.0474 0.99 660.38 <0.0001
a Reprinted with permission from Lam PS, Sokhansanj S, Bi XT, and Lim CJ.2012. Colorimetry applied
to steam-treated biomass and pellets made from western Douglas fir ( Pseudotsuga menziesii L.).
Transactions of the ASABE 55(2): 673-678. St. Joseph, Mich.: ASABE

lightness), a * (redness or greenness), and b * (yellowness or blueness). MLR models
were created from range-scaled factors of elemental composition, i.e., percentages
of C and H of the untreated and steam-treated samples at different treatment
temperature and time. By the use of range-scaled factors, differences in magnitude in