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A method was developed for measuring the rate of leaching of lignin macromolecules from the fibre walls of unbleached kraft pulp fibres suspended in water. From a comparison of a theoretical analysis with experimental results, it was concluded that the leaching process was governed by a diffusion mechanism. Very low and widely polydisperse diffusion coefficients were observed for this system. The molecular weights of the leached lignins were found to increase with wash time. A comparison of the molecular dimensions with pore size indicated that a flat disk-like conformation, rather than a spherical conformation was appropriate for the lignin macromolecule. From 20(DEGREES) C to 70(DEGREES)C the change in the intrafibre diffusion coefficient with temperature varied directly as the ratio of the absolute temperature to the viscosity of water. Above 70(DEGREES)C there was a much larger dependence of the diffusion coefficient on temperature. The rate of leaching was also affected by the presence of electrolytes in the wash liquid; leaching was found to decrease with an increase in the ionic strength of the electrolyte. A conceptual model for this leaching effect is presented. The model offers a qualitative explanation for the experimental results noted above.

Graduation date: 1975

The main purpose of this study was to determine the effect of contour height on the passage ratio of pulp through screen apertures, and determine which operating variable has the greatest affect on screen performance. In addition, a freeness model was to be developed, in hopes of helping to predict the freeness drop between feed and accepts. The study was conducted at The University of British Columbia (UBC) using a laboratory scale pressure screen. Slot velocity, feed consistency and contour height were the changing variables. Samples were collected from which passage ratio, freeness, fibre length and coarseness were determined. From the studies conducted it was found that slot velocity had the greatest influence on the screen operation. As the slot velocity increased a greater force was applied to the fibre to help push it through the screen aperture. However, this increase in slot velocity decreases the fractionation ability (separation of fibres into different lengths) of the screen. The second most important variable was the contour height. The main function of the contour height is to disrupt the flow of thick stock at the wall of the screen and allow for unhindered movement of fibre to the screen wall. The greater the contour height is, the greater the passage ratio (pulp fibre passing through screen). However, there is a decrease in fractionation. The third most important factor was the feed consistency. At low feed consistencies there is less crowding in the screen. Less crowding leads to more loosely-formed flocs, which are easier for the contour height and the rotor to dissipate and thus leads to unhindered movement. Thicker feed stock has a negative effect on passage A Freeness model was developed that showed that freeness had a power law relationship to passage ratio. The passage ratio was raised to a constant B, which is a function of the contour height and the feed consistency.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Human adult dental pulp cells (DPSC) reside within the perivascular niche of dental pulp and are thought to originate from migrating cranial neural crest (CNC) cells. During development, CNC cells respond to the environmental cues to migrate and differentiate into the different cell types that contribute to the formation of craniofacial structures and the peripheral nervous system. The Eph family of receptor tyrosine kinases and their ligands, the ephrin molecules, play an essential role in the migration of neural crest cells during development and postnatal stem cell (SC) niche maintenance. "The present study demonstrated multiple Eph receptors expressed primarily on DPSC within the perivascular niche, while the surrounding pulp tissue expressed ephrin-B ligands. EphB/ephrin-B bi-directional signalling inhibited DPSC attachment and spreading, while DPSC migration was restricted through uni-directional ephrin-B1 activated EphB forward signalling in vitro. Furthermore, we observed that ephrin-B was down-regulated in diseased adult teeth compared to paired uninjured controls. Collectively, these studies suggest that EphB/ephrin-B molecules play a role in restricting DPSC attachment and migration in order to maintain DPSC within their SC niche under steady-state conditions. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1274738 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007

The purpose of this dissertation is to redress the literary academy’s view of Pulp Literature as an inconsequential form, which does not merit serious contemplation, or artistic recognition. Although it is true that recent literary criticism has attempted to elevate the importance of Pulp by positing it as the natural postmodern “other” to ‘high’ literature, the thesis demonstrates how this dichotomy has proven to be counter-productive to its aim. That is, although this theoretical approach does invite legitimate investigation of the form, many academics simply use this technique to reinforce their claims for the superiority of so-called ‘canonic’ texts. Therefore, rather than continuing along this downward path, this thesis focuses more on the subversive machinations of Pulp Literature as a social, economic, political, and theoretical force with its own strategies and agendas, opening with an investigation of the history of Pulp Literature as a cultural form. I argue that, from its very conception with the invention of the printing press in the fifteenth century, Pulp has always offered a radical alternative to the mainstream by providing a voice for the marginalised and the oppressed in the societies of the world. The thesis traces this political role as the aesthetic evolves into the new forms and technologies of a contemporary culture, where many academics still refuse to acknowledge Pulp as an important agent for the transmission of ideological views, and an impetus to instigate social change. The concluding arguments move away from the quantitative, to the more theoretically evaluative section of the thesis. This consists of a discussion of the conceptual boundaries surrounding the aesthetic of Pulp, broaching such subjects as literary evaluation, canonicity, and canon formation. This debate ultimately revolves around the question, ‘if literary theorists cannot ‘objectively’ determine what literary ‘quality’ is, then how can we hope to define Pulp?’ In an attempt to answer this question, the thesis juxtaposes the criteria of a number of literary theorists from this field of inquiry, namely, Thomas R. Whissen, Clive Bloom, Thomas J. Roberts, Harold Bloom, Andrew Calcutt and Richard Shephard, to formulate an aesthetic that is not only markedly different to their’s, but more significantly, one which situates Pulp Literature at the head of the literary academic table.

Thesis (M.S.)--Virginia Polytechnic Institute. / Also available via the Internet.

Thesis (B.A.Hons.) - Dept. of Politics, University of Adelaide, 1981. / Typescript (Photocopy).