The objectives of this study are: l. To determine the adequacy of markets for paper products. 2. To identify and quantify the costs of the factors affecting pulp and paper production. The available information indicates that adequate markets exist for paper produced in Utah. Chemicals, water, labor, and power are available at costs low enough not to prohibit pulp and paper production. An adequate, low priced supply of wood could be purchased from the United States Forest Service. Intermountain and national paper markets would enable a paper producer in Utah to take advantage of lower comparative transportation costs.

Pressure screens are used for contaminant removal and fibre length fractionation in the production of pulp and paper products. Axial variations and entry effects in the screen are known to occur and these variations have not been adequately quantified. This thesis describes a fundamental study of the axial variations of several factors that occur within an industrial pressure screen; namely, pulp consistency, fibre length distribution, rotor pressure pulse, and feed annulus tangential velocity. Axial variations of pulp consistency in the screen annulus and the accept chamber of the screen were studied using an internal radial sampling method. Localised pulp samples were taken and evaluated and common measures of screen performance such as fibre passage ratio and fractionation efficiency were calculated along the screen. Consistency generally increased along the length of the screen although under certain conditions the consistency toward the front of the screen was lower than the feed consistency. A two passage ratio model that incorporated forward and reverse passage ratio was derived to elucidate the flow of both fibre and fluid through the screen and their effects on overall screen performance. The passage of fibre through the screen decreased with screen length which generally had a positive effect on the fractionation efficiency toward the back of the screen. The passage of individual fibre length fractions was also studied and it was found that long fibre had a much lower passage than short fibre which caused the average fibre length in the annulus to increase. Rotor induced pressure pulse variations along the screen length were also investigated. The magnitude of the pressure pulse was significantly lower (up to 40 %) at the rear of the screen. The variation in pressure caused by the rotor is due to a Venturi effect and the shape of the rotor. The relative velocity of the fluid and the rotor, called the slip factor, also directly affects the size of the pressure pulse in the annulus. The slip factor decreases along the length of the screen due to the increase in tangential velocity of the fluid. Pressure pulse data was also used to estimate the instantaneous aperture velocity and back-flush ratio. The instantaneous aperture velocity was calculated to vary considerably from the superficial aperture velocity by up to 5 m/s in the forward direction and 10 m/s in the reverse direction. Computational Fluid Dynamics (CFD) was used to model tangential velocity changes in simplified screen annuli with axial through flow. For a smooth screen rotor the mean tangential velocity increased over the entire length of the annulus without reaching a maximum value. A step and bump rotor were modelled and the shape of the pressure pulses showed good agreement with experimentally measured pulses. The mean tangential velocity and the entrance length were found to be heavily dependant on the screen rotor used.

Thesis (M.S.)--Oregon State University, 1970. / Typescript. Mounted photographs. Includes bibliographical references (leaves 64-69). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 108-115). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1967. / Typescript (photocopy). Includes bibliographical references (p. 52-60). Also available on the World Wide Web.

No description available.

Thesis--Karolinska Institutet, 1971. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 27-29).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1956. / Includes bibliographical references (p. 110-113).

Thesis (Ph. D.)--University of Hong Kong, 1987.

The pulp organ is retained in the pulp chamber of teeth and maintains the biological and physiological vitality of the surrounding dentin. It works as a biosensor and generates secondary dentine and tertiary dentine to resist tooth abrasion and pathogenic stimuli (Zhang and Yelick, 2010). However, dental pulp is vulnerable to injury (Smulson and Sieraski, 1989). Most people experience some irreversible pulpal diseases during their lifetime. Hence, pulp regeneration is one of the research tasks in dentistry that attracts much attention. Stem cell transplantation is a plausible strategy for the regeneration of dental pulp organ. Dental pulp stem cells (DPSCs)derived from heavy or inflamed dental pulps have the natural advantage in pulp regeneration due to its dentinogenic potentiality (Huang et al., 2009). DPSCs are delivered into prepared root canal, which then differentiate into odontoblasts, fibroblasts, and other kinds of cells. It was shown that these transplanted DPSCs were able to produce dentin and formed a dentin-pulp like tissue both in vitro and in vivo(Huang, 2009).However, low survival rate of the transplanted cells is a common problem in pulp regeneration. Overexpression of Bcl-2 could enhance cell anti-apoptotic ability. Studies of many kinds of cell transplantation showed that a large number of cells died upon grafting and a large proportion of cell death seemed to have occurred due to apoptosis (Liu et al., 2013; Zhang et al., 2001).The aim of this study was to improve cell survival through making DPSCs overexpress lymphoma 2 (Bcl-2) protein.Bcl-2 is a proto-oncogene which playsa significant role in (anti) apoptosis. Former studies in the literature have provided evidences that overexpressing Bcl-2 could reduce cell apoptosis. However, this strategy has not been studied in the modification of DPSCs. In this study, DPSCs were isolated from discarded third molars of adults and manipulated to overexpressing Bcl-2. Proliferation of modified DPSCs was analyzed by static batch culture, CCK-8 test and BrdU based proliferation test. Apoptosis of modified DPSCs was analyzed by measuring DNA fragments in the cells. Modified DPSCs generated a higher maximum cell population during static batch culture and showed higher viability (the ratio of live cells to total cells). CCK-8 test showed that the population of modified DPSCs increased faster than control group cells and wild type cells. Modified DPSCs were not better than the other cells in proliferative ability, but had lower apoptosis level when culturing in serum free medium. Hence, overexpressing Bcl-2 could increase cell population, the mechanism is to help DPSCs survival rather than promote the proliferative ability of cells. / published_or_final_version / Dentistry / Master / Master of Philosophy