Effects of Some Wood Chip Properties on Pulp Quality
A series of TMP experiments were performed at CIPP’s TMP pilot plant, and some pulp properties were measured. By comparing chip and pulp properties, and using projections to latent structures (PLS) analysis, we were able to demonstrate that on-line CMS measurements can be used to predict some pulp properties. It should be pointed out that the focus of this paper is to show how CMS measurements can be used to predict some pulp properties. This prediction will suggest ways to control chip quality so as to ensure pulp quality. We tried to explain some important chip properties included in the measurements, but did not try to model them.
Determination of Moisture Content and Basic Density of Poplar Wood Chips under Various Moisture Conditions by Near-Infrared Spectroscopy
The potential of near-infrared (NIR) spectroscopy coupled with partial least-squares (PLS) regression was used to determine the moisture content and basic density of poplar wood chips. NIR spectra collected from the surface of wood chips were used to develop calibration models for moisture content and basic density predication, and various spectral preprocessing techniques were applied to improve the accuracy and robustness of the prediction models. The models were tested using totally independent sample sets and exhibited acceptable predictive performance for moisture content (coefficient of determination for prediction [R2p] = 0.98 and standard error of prediction [SEP] = 2.51 percent) and basic density (R2p = 0.87 and SEP = 17.61 kg m–3). In addition, the effect of moisture variations on prediction of basic density was investigated based on NIR spectra from wood chips under various moisture levels. The results demonstrated that broad absorption bands from water molecules, especially when free water exists in the cell lumen, overlap with informative signals related to wood properties and weaken the calibration relation between spectral features and basic density. Thus, maintaining wood chips in a low and even moisture state would help achieve reliable estimates of wood density by NIR analysis models.
Wood Fluorescence of Indigenous South African Trees
The fluorescence characteristics of South African hardwoods and their extracts were studied to determine their value in wood identification. Heartwood specimens and water and ethanol extracts of a1together 179 species representing 108 genera and 46 farnilies were exarnined in longwave ultraviolet light. Additional tests were conducted for the presence of Aluminium natural saponins. The findings of this research correspond with the current knowledge on wood fluorescence. The families Leguminosae, Rutaceae and Anacardiaceae showed positive fluorescence for the majority of their species. Platylophus trifoliatus is the only indigenous species with a positive reaction to the test for Aluminium. The froth test for natural saponins in wood has variable results, restricting its significance in wood identification. These results show that fluorescence is a useful characteristic in wood identification and may be applied as a rapid and easy test to verify certain identifications.