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Gas hydrodynamics and mass transfer in low- and medium-consistency pulp suspensions in a retention towerIshkintana, Linda Kate 11 1900 (has links)
In the pulp and paper industry, the interaction between the gas, liquid, and solid phases occurring in various unit operations is often not clearly understood. Such multi-phase operations include flotation deinking (a separation process of paper fibres in the recycling process) as well as the delignification and bleaching operations in the kraft pulping process. Much of the design, operation, and optimization of such processing equipment are dependent upon past experience as well as trial-and-error methodologies.
Pulp fibre suspensions possess a complex and unique rheology. The unpredictability of the behaviour of pulp suspensions at any given mass concentration is due to the bonding between the fibres resulting in network formation (which depends on suspension consistency) with this interaction creating complexity in fluid flow in various unit operations.
This thesis describes the gas hydrodynamic behaviour and gas-liquid mass transfer characteristic in low- and medium-consistency pulp suspensions in batch operation. First, the hydrodynamic behaviour of the gas phase (air) in water and pulp suspensions having mass concentrations up to Cm = 7% is examined by visually observing and recording the bubble shape, size, and rise velocity in a rectangular channel. Results are obtained using a high-speed video camera. Second, the hydrodynamic behaviour is described in terms of the gas holdup along with axial and radial gas phase distributions in water and kraft pulp suspensions having mass concentrations between Cm = 0.5 and 9% in a batch-operated cylindrical bubble column. The gas holdup results are compared using three methods: the suspension height method, the pressure difference method, and the electrical resistance tomography (ERT) method. Finally, the volumetric gas-liquid mass transfer characteristic of air in water and kraft pulp suspensions having mass concentrations up to Cm = 4% is examined in the same bubble column in batch-operation using a dissolved oxygen probe.
Experimental results were comparable to that in literature for water and for pulp fibre suspensions having Cm < 2%. The presence of fibres had a significant effect on the gas holdup and mass transfer characteristic with results providing insight on the limitations that exist in industrial pulp unit operations.
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A survey of the pulp and paper industry in the state of Oregon in relation to land use /Spaur, George. January 1937 (has links)
Thesis (M.S.)--Oregon State College, 1937. / Typescript. Includes bibliographical references (leaves 126-129). Also available on the World Wide Web.
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Bacterial penetration into root canal dentineKhan, Ali Akbar. January 2007 (has links)
Thesis (M.D.S.)--University of Hong Kong, 2008. / Also available in print.
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A clinical and radiographic evaluation of the effect of calcium hydroxide in direct pulpal capping of exposed pulps in primary teethWeine, David M. January 1962 (has links)
Thesis (M.S.)--University of Michigan, Ann Arbor, 1962. / Typescript (photocopy). Includes bibliographical references (leaves 42-45). Also issued in print.
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The effect of Dycal® on bacterial metabolism and viability in deep carious lesionsKnight, G. William. Marchelya, Lawrence S. January 1981 (has links)
Thesis (M.S.)--University of Michigan, Ann Arbor, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 59-62). Also issued in print.
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Gas-liquid mass transfer in oxygen delignification systems /Krothapalli, Deep. January 2004 (has links)
Thesis (M.S.) in Chemical Engineering--University of Maine, 2004. / Includes vita. Includes bibliographical references (leaves 113-116).
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Application of secondary fluorescence to measure the kappa number of single fibers /Liu, Yue, January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [92]-97).
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Systemic tetracycline effect on endodontic cultures a thesis submitted in partial fulfillment ... in endodontics ... /Burke, Joseph Harold. January 1970 (has links)
Thesis (M.S.)--University of Michigan, 1970.
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On pulpectomies an experimental study in dogs with special reference to microangiography and histology /Strömberg, Torsten. January 1971 (has links)
Thesis--Karolinska Institutet, 1971. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 27-29).
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Systemic tetracycline effect on endodontic cultures a thesis submitted in partial fulfillment ... in endodontics ... /Burke, Joseph Harold. January 1970 (has links)
Thesis (M.S.)--University of Michigan, 1970.
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