About: Appita Journal is an academic journal. The journal publishes majorly in the area(s): Pulp (paper) & Kraft process. It has an ISSN identifier of 1038-6807. Over the lifetime, 696 publication(s) have been published receiving 6664 citation(s).
Papers published on a yearly basis
01 Jan 1999-Appita Journal
TL;DR: In this paper, a new method was presented for estimating microfibril angle in wood by X-ray diffractometry, where the variance, S 2, of the azimuthal 002 (cellulose I) diffraction profile was shown to be related to micro-fibrils angle, μ, by a very simple approximate relationship: S 2 =μ 2 /2+σ 2, where σ is the standard deviation of micro-bibril orientation about μ.
Abstract: A new method is presented for estimating microfibril angle in wood by X-ray diffractometry. The variance, S 2 , of the azimuthal 002 (cellulose I) diffraction profile is shown to be related to microfibril angle, μ, by a very simple approximate relationship: S 2 =μ 2 /2+σ 2 , where σ is the standard deviation of microfibril orientation about μ. Advantages in interpretation flow from the principle of variance additivity, making possible the analysis of composite diffraction patterns accumulated over regions of wood with strongly varying microfibril orientation. Experimental advantages include insensitivity to fibre cross-section shape, the orientation of the fibre about its axis, and noise in the diffraction pattern.
01 Jan 2000-Appita Journal
TL;DR: SilviScan-2 was used to estimate and map microfibril angle (MFA) and density in twenty-nine 15-year-old Eucalyptus nitens trees as discussed by the authors.
Abstract: SilviScan-2 was used to estimate and map microfibril angle (MFA) and density in twenty-nine 15-year-old Eucalyptus nitens trees. Over 4000 MFA measurements were made at about 100/hour. Each measurement represented a weighted average for about 50000 fibres. After an initial decrease near ground level, density increased with height in the stem. MFA decreased with height in the stem, reached a minimum around 30 to 50% of tree height, then increased towards the top. In the radial direction, density first decreased for a few years, then increased towards the bark. MFA was in the range 20 to 30 degrees near the pith at all heights and generally decreased towards the bark over most of the height of the stem. The lowest MFA values (approx. 10 degrees) were found close to the bark at 30 to 50% of stem height. Both density and MFA varied more rapidly near ground level, increasing the uncertainty of correlations between breast-height properties and whole tree properties. On some samples, high-resolution (0.2 mm) MFA scans were performed to confirm an earlier finding that MFA is strongly inversely correlated with density over a few growth rings but not over larger distances. X-ray diffraction was also used for estimating the orientation of the fibres within the samples. The radial variation in fibre orientation generally decreased with distance from the ground. Breast-height sample properties were moderate to good predictors of whole tree properties. Better correlations were obtained using samples from 5.5 m. Whole tree average density and MFA were found to be uncorrelated, indicating that tree improvement strategies could be designed to simultaneously optimise these properties.
01 Jan 1995-Appita Journal
TL;DR: In this article, the tracheid cross-section dimensions of a 19 year old radiata pine tree were mapped for properties important to the pulp and paper industry: wood density, wall thickness, coarseness and wall thickness.
Abstract: Variation in tracheid cross-section dimensions has been mapped in a 19 year old radiata pine tree. An instrument recently developed for the rapid estimation of transverse tracheid dimensions was used for the analysis. Sixty radii (four directions at each of fifteen heights) were processed. Variation was mapped for properties important to the pulp and paper industry: wood density, tracheid perimeter, coarseness and wall thickness. In this tree, coarseness, wall thickness and density trends were approximately linear from pith to bark, and the rate of rise was similar at all sampling heights. As a result, variation of these properties in the three was approximately cylincrically symmetric. Average coarseness, density and wall thickness fell by 25% from the 0.8 metre level to the 20 metre level in the tree. Average tracheid perimeter was almost independent of sampling height. At breast height, coarseness rose by 86% from pith to bark (350 to 650 μg m -1 ), density rose by 45% (380 to 550 kg m -3 ) and wall thickness by 57% (2.1 to 3.3 μm). Unweighted breast height core properties for this tree were similar to volume-weighted whole tree properties above breast height. Correlations between properties such as coarseness and wall thickness were strong when ring averages or trends were considered, but poor within individual tree rings. Understanding of the mechanisms of short term regulation of tracheid properties should allow increased selectivity in the silvicultural and genetic control of individual properties
01 Jan 1995-Appita Journal
TL;DR: In this article, a method for providing a rapid estimate of pulpwood quality based on small samples using near-infrared spectroscopy has been examined, where three trees were drawn from three trees in ten provenances of Tasmanian Eucalyptus globulus.
Abstract: Near-infrared spectroscopy has been examined as a method for providing a rapid estimate of pulpwood quality based on small samples. The woods were drawn from three trees in ten provenances of Tasmanian Eucalyptus globulus. The measures of pulpwood quality were yield, soda charge at Kappa number 15, total lignin, and hot water and alkali solubles. The samples were divided to provide 24 which were used in obtaining the calibrations and six which served as unknowns. The calibrations were obtained by using standard. Norris and partial least squares regressions. Predictions of the various pulpwood quality measures were obtained with residual standard deviations in the range 0.8-2.6 units.
01 Jan 1996-Appita Journal
TL;DR: In this paper, the polysaccharides in a series of Eucalyptus globulus and E. nitens pulps were analyzed by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), following hydrolysis with sulfuric acid.
Abstract: The polysaccharides in a series of Eucalyptus globulus and E. nitens woods, and E. globulus pulps, were analysed by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), following hydrolysis with sulfuric acid. The technique was evaluated as a small-scale method for characterising mltiple samples of eucalyp woods. Acetyl groups and 4-0-methylgluronic acids (MeGUAs) associated with the hemicellulose, fraction were removed during acid hydrolysis and were determined separately. Acetyl and MeGUA results were combined with the hydrolysis results to enable calculation of cellulose and hemicelluloses contents for each sample. The cellulose content of the wood samples varied over the range 41-50% (E. globulus) and 36-44% (E. nitens), although the range of total polysaccharide contents was similar for both woods. Analysis of the pulp polysaccharides after enzymic hydrolysis showed that the pulps contained hexenuronic acids. The analyses for cellulose and hemicellulose content showed satisfactory precision, and gave values similar to those associated with gravimetric determination of cellulose and hemicelluloses. The hydrolysis-HPAECPAD method for carbohydrates is proposed as a better alternative to gravimetric techniques for exploring the relationship between the chemical composition of plantation eucalypt woods and their pulp yields and papermaking properties.
Related Journals (5)
Industrial Crops and Products
9.7K papers, 278.9K citations
ACS Sustainable Chemistry & Engineering
10.5K papers, 248.9K citations
8.9K papers, 526.1K citations
Industrial & Engineering Chemistry Research
36K papers, 1M citations
8.4K papers, 457.5K citations