PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 6, Number 2, 2019
scanning microscopy. The enthalpy changes accompanying the mixing of cationic PAMs with oxidized starch was determined using an isothermal titration calorimeter to see the molecular level interaction between PAM and starch in mixing. The addition of cationic PAM to oxidized starch solution made starch molecules stay on the paper surface rather than penetrating into the paper structure. Influence of fiber composition and drying conditions on the bending stiffness of paper, Ham, C.-H., Youn, H.J., & Lee, H.L., BioResources , 15(4), DOI: 10.15376/biores.15.4.9197-9211. Changes in thickness, elastic modulus, and bending stiffness were studied for handsheets prepared using different fiber compositions and dried under restraint or unrestraint conditions, when exposed to various humidity conditions. Four sets of experimental studies were carried out to investigate the effect of (1) different amounts of fines (or long fibers), (2) two-ply sheet forming, (3) high temperature restraint press drying, and (4) the use of recycled fibers on the thickness, elastic modulus, and bending stiffness. The results showed that thickness, elastic modulus, and bending stiffness changed depending upon the fiber composition, single or multi-ply forming, drying conditions, and recycling of fibers. Thickness change, restraint drying, and fiber hornification during recycling were the principal factors affecting the bending stiffness in cyclic humidity conditions. PULP Modelling of dewatering wood pulp in a screw press using statistical and multivariate analysis, El Idrissi, B., Loranger, É., Lanouette, R., Bousquet, J.P., and Martinez, M., BioResources , 15(3), DOI: 10.15376/biores.15.3.5899-5912 . Statistical modeling of a screw press was established by using an experimental design based on the screw rotational speed, the pulp feed consistency, the pulp feed suspension freeness, the inlet pressure, and the counter-pressure at the discharge end. The statistical models showed that the screw press outputs for each pulp could be predicted. When including all data in a global model to predict the outputs of the press for any pulp, a global statistical model was found not to be efficient by using just the five fixed parameters. The solution to this problem was to use a multivariate analysis to include more parameters, mainly about the fiber characteristics (crowding factor, fiber length, fiber width, and fines content). By including these fiber properties, the differences between each pulp were more properly analyzed. The multivariate analysis predicted the press outsets very well in a global model by using eight parameters instead of five. The R2 values of the multivariate prediction model were all higher than 0.70 and had the goodness of prediction (Q 2 ) higher than 0.60. TESTING Research review on devices and methods for rapid measurement of paper ash, Hu, L., Lu, X., & Ma, J., BioResources , 15(1), 2096-2110, DOI: 10.15376/biores.15.1.2096- 2110. The Chinese national standard for paper ash measurement cannot meet the requirements for accurate and rapid ash measurement in actual production and scientific research because of the long measuring time, tedious procedures, and large human error. This paper reviews some worldwide devices and methods for rapid measurement of paper ash, including ceramic fiber muffle furnace, microwave muffle furnace, the addition of ash adjuvant, dry samples method, direct combustion of paper samples, oxygen-enriched combustion method, chemical analysis method, and ray method, etc. The differences and relationships are identified among these devices and methods. By comparing the different ash measurement methods, the rapid ash analyzer based on X-ray technology has the obvious advantages of short measuring time and small error. Lastly, the present situation and the development potential of these devices and methods are discussed in this review.
Technical Abstracts
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