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A series of laboratory oxygen delignification were performed in this study at constant oxygen pressure and consistency to study the response of the pulp to the different process parameters, i.e. reaction temperature, reaction time, soda addition, and mechanical pretreatment, to the zero span tensile strength loss. The basic chemistry of the oxygen delignified pulps was under study including fiber charge, celluloses/hemicelluloses, and hexenuronic acid. The fiber structure such as curl, kink, fines, and fiber length were also discussed. NaOH charge can be reduced as much as 50 % by applying mechanical pretreatment to obtain the same level of selectivity at the oxygen delignification conditions described in this study.Mechanical pretreatment prior to oxygen delignification promoted a better selectivity for both Acacia mangium and MHW pulps. MHW kraft pulp did not show a significant extractive removal in all pretreatment methods during oxygen delignification. The ultrasonic pretreatment followed by filtering induced the best extractive removal among the other three methods.

The wicking properties of multi-ply paper samples with dissimilar plies were investigated. These materials exhibit wicking performance in excess of either of their individual plies. Samples were produced from a ply of softwood pulp and a ply of hardwood pulp of equal caliper and basis weight. The softwood sample possessed a larger average pore size, a fact verified via porometry. Samples of a single ply were also produced for comparison. The samples were tested using both upward and downward gravimetric wicking tests. There was no saturation gradient observed, however there was a variation in the degree of bulk expansion during wicking. Capillary pressure and permeability for the various sample types were determined from the results of these tests and compared. It is shown that the wicking performance of the two ply sample is comparable to that of a theoretical material with the capillary pressure of the hardwood ply but the permeability of the softwood ply. Wicking in two-ply samples was also observed in an NMR apparatus. This was used to determine that the hardwood ply leads during wicking, and observe the rate of saturation as well as bulk expansion. A third type of experiment tracked the transport of dyed water from one ply to the other, establishing the direction of fluid transport during wicking to be from the softwood ply to the hardwood ply. The theory is proposed, based on these results, that wicking in this type of material consists of a smaller pored leading ply that draws water from a more permeable larger pored material that acts as a moving reservoir.

The area of the digital image processing is getting more attention in the hope that it will increase the accuracy of any scientific measurements, such as in determining an object velocity, temperature, and size. While human vision is excellent to recognize and differentiate objects, it has been proven to be a poor tool when it comes to measure the object performance. One of many digital image processing applications is texture analysis whose purpose is to evaluate image patterns. The purpose of this dissertation is to investigate the use of texture analysis as a tool to micro fiber dispersion measurement. Micro fiber dispersion can be found in many applications such as in paper and industry powder engineering. Three cases related to micro fiber dispersion were investigated in this study. The first case was the experimental study of the dispersion in open water channel. Sets of synthetic fibers were put into water channel to simulate a process that can be found in papermaking industry. The research investigated the effect of three operating parameters: fluid velocity, fiber consistency, and fiber aspect ratio to fiber dispersion. Using two-factorial experimental design technique, the main and interaction effects of these parameters were evaluated. The study found that increasing fluid velocity, fiber aspect ratio, and consistency decreased the dispersion level. The study also found that the effect of individual parameters is more pronounced than the role of the interactive terms on the fiber flocculation. The second case considered was applying the fiber dispersion analysis to computer-synthesized images consisting of different arrangements of fibers. Four sets of sub-cases were presented. These sub-cases were divided based on the fiber-concentrated location and fiber distribution. The use of computer-synthesized images was found to be very useful to simulate real situation during fiber dispersion. The third case investigated the fiber distribution on a dry paper. Images for different types of paper were taken and evaluated to see the dispersion level of each type of paper. It was found that the current texture analysis was applicable to determine the dispersion level for dry papers. While three cases indicated that the texture analysis can be used to investigate the fiber dispersion, the texture analysis used here is not a perfect and universal method and may not be suitable to analyze other types of dispersions. The human vision will always be essential to determine if the texture analysis is applicable to any other problem.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed on Feb. 3, 2010). Includes bibliographical references (p. 38-42).

Thesis (M.D.S.)--University of Hong Kong, 2001. / Includes bibliographical references.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1940. / Includes bibliographical references (p. 75-77).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1951. / Includes bibliographical references (p. 221-223).

Thesis (Ph. D.)--Institute of Paper Science and Technology, 1989. / Includes bibliographical references (p. 169-177).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1966. / Includes bibliographical references (p. 102-106).