The objective of this project was to study systematically the NSSC-AQ pulping process in order to improve the penetration of anthraquinone and sodium sulfite in wood and to simulate the mass transfer and delignification processes. / In a heterogeneous reaction system, such as wood pulping, two main factors control the overall reaction rate: liquor penetration and chemical diffusion. As a first step, some wood characteristics affecting liquor impregnation were evaluated: 1) fiber hydraulic radius, 2) air, steam and water content, 3) wood elasticity and compressibility. Secondly, impregnation and pulping experiments were performed while varying the pre-steaming, compression and soaking time. Finally, experimental profiles were compared to computer simulated results. The two most commonly used species by the pulp industry were chosen for this study: 1) black spruce sapwood and heartwood as well as 2) trembloid poplar sapwood. / Impregnation of sulfite-AHQ liquor in wood blocks was simulated by a three-dimensional "Control Volume Finite Difference Method (CVFDM)". To de-couple the pressure and velocity fields, typical to convection-diffusion problems, a mass balance around individual control volume was performed using Poiseuille's capillary flow equation. The pulping kinetic differential equations were included into the CVFDM model to simulate a three-dimensional delignification pattern in the wood. / In general, the progression of the anthraquinone impregnation was slow and non-uniform in comparison to sulfite which penetrated rapidly and uniformly during pulping. Furthermore, delignification uniformity was related to the initial chemical profiles observed after impregnation. This confirms the importance of chemical pre-treatment for high yield pulping in order to minimize uneven delignification for chips thicker than 3mm. Results showed that, in most cases, computer simulated profiles were similar to experimental anthraquinone and sulfite impregnation patterns.

Microparticulate retention aids, consisting of a high molecular weight polymer used in conjunction with inorganic microparticles, are widely used to improve the process colloid retention in papermaking. Such additives are generally introduced to the paper stock prior to the web formation, so that fines and fillers are flocculated and retained into the forming web. This study investigated the mechanism of fines and filler retention under the high shear typical of papermaking. Retention and drainage were optimized using the newly built Laboratory Twin Former. The variables of interest include the concentrations of a cationic polyacrylamide polymer (CPAM) and bentonite, and their residence times with the furnish. The former variables provide information for optimal bridging efficiency between the furnish components, while the latter variables indicate the appropriate location for adding the retention aid to reach maximum retention. The experimental results indicated that the bridging theory well predicts a maximum retention when only CPAM is used. For the microparticulate system, a longer residence time of bentonite in the furnish is preferable so that the fines retention improves by allowing sufficient time for colloids coagulation and by promoting bentonite deposition on the polymer coated fines. We also studied the mechanism of fines retention and quantified the drainage rate at the jet impingement region, with and without retention aids. By individually varying the jet velocity and the jet angle, the two velocity components of the jet, i.e. VjetX and VjetY were controlled. The slice opening and the wire velocity were kept constant. For the range investigated, the drainage force proportional to V jetY had little effect on fines retention or drainage. A high shear impact on the wire by increasing the jet velocity, and consequently by augmenting VjetX relative to the wire speed, reduced the fines retention and restricted the drainage rate.

A new three-dimensional finite solid element (3D FE) model for dowel-type wood connections was developed using the concept of a beam on a nonlinear wood foundation, which addresses the intricate wood crushing behaviour under the connector in a dowel type connection. In order to implement the concept of wood foundation with solid elements, a 3D FE wood foundation model was defined within a prescribed foundation zone surrounding the dowel. Based on anisotropic plasticity material theory, the material model for the foundation zone was developed using effective foundation material constants that were defined from dowel-embedment test data. New 3D FE single nail connection models were developed that incorporated the wood foundation model. The 3D wood foundation model was justified and validated using dowel-embedment test data with a range of dowel diameters, from a 2.5-mm nail to a 25.4-mm bolt. The connection models provided successful results in simulating the characteristics of load-slip behaviour that were experimentally observed. Based on the success of the single nail connection models, several applications of the 3D FE connection models were investigated including statistical wood material models, bolted connection models and a multiple nail connection model. Throughout the application studies, discussion of the benefits and limitations of the new model approach using the 3D FE wood foundation are presented. Also, future areas of study are proposed in order to improve the 3D FE dowel-type wood connections models.

Floods are considered to be among of the deadliest, costliest and most common natural disasters. Rapid onset, catastrophic floods inundate the shore quickly and manifest as deep water with high velocities. The deep water and high velocities caused by these floods inflict great pressures and forces on the built and natural environments and pose a threat to human safety. Recent disasters such as Hurricane Katrina in the Southern United States and the Sumatra tsunami in the Indian Ocean have revealed that communities at risk require improved preparations for these types of dangerous events. Current building codes, design practices and disaster planning methods account for potential earthquake and wind loads on simple wood frame buildings typical of North American residential construction, however, flood impacts have not been considered in the same level of depth. The objectives of this research are to develop a theoretical model that describes flood impacts on wood frame residential buildings and relates building response to physical flood properties such as depth and velocity. This thesis provides a brief synopsis of previous approaches used to describe building response to flooding. An overview of the major loads caused by rapid onset flooding, along with a description of the structural system utilized in wood design to resist these forces is provided. The failure mechanisms considered and the model logic are described and applied to assess the response of a typical Canadian wood frame home to flood conditions that might be experienced in a rapid onset flood event like a tsunami. Building response results are discussed along with recommendations for future analysis and applications.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on February 28, 2008) Vita. Includes bibliographical references.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1989. / Includes bibliographical references (leaf 127).

Thesis (M.S.)--Oregon State College, 1937. / Typescript. Includes bibliographical references (leaves 126-129). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1991. / Typescript (photocopy). Includes bibliographical references (leaves 115-123). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 46-49). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 145-153). Also available on the World Wide Web.