Magnesium oxide-based additives have been used in kraft recovery boilers to minimize deposit accumulation on superheater and generating bank tubes. Due to inconclusive results observed in boilers and claims made for additive effectiveness backed by little scientific evidence, only a few mills still use the additives for fouling control. A systematic study was performed to examine the effect of MgO-based additives on deposit accumulation and removal under controlled laboratory conditions, and to evaluate the additive effect in a kraft recovery boiler. The results show that while the additive coating has no effect on deposition, it could ease deposit removal if a coating greater than 5 µm can be applied on the tube surface effectively. Separate injection of additive and black liquor had insignificant effect on deposition and removal. Results of the field study show that the amount of additive collected on the tube is too small to have an impact.

Resin and fatty acids (RFA) are predominantly components of coniferous trees having the natural function of protecting against microbial damage. These compounds are released from wood during the pulping process and a fraction reaches the wastewater treatment system. RFA are acutely toxic to aquatic organisms at concentrations on the order of parts per million, and their presence has been linked to toxicity outbreaks in receiving waters following process upsets. The chronic toxicity of resin and fatty acids in complex effluent matrices is poorly understood. Furthermore, the role of hydrophobic, pulp-derived solids as a removal pathway from wastewater streams has not been comprehensively studied. The objectives of this dissertation have been to quantify the relationship between resin and fatty acid concentration and chronic toxicity and to determine the role of partitioning in the removal of these compounds from pulp mill wastewater streams. Field and laboratory studies were conducted to measure toxicity using the Microtox™ whole effluent toxicity and Ceriodaphnia dubia 7-day, survival and reproduction bioassays. One resin acid in particular, dehydroabietic acid, was found to account for a significant fraction of final effluent chronic toxicity. Dissolved and sorbed RFA concentrations were quantified by solvent extraction, methyl ester derivatization, and GC-FID analysis. Partitioning to suspended solids was found to be a major removal pathway for the RFA from the effluent treatment system. A kinetic model for flotation was applied and compared to experimental data. Flotation was found to be effective at selectively removing RFA bound to pulp-derived solids from pulp mill and bleach plant sewers at moderate to high pH.

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 (Ph. D.)--Institute of Paper Chemistry, 1939. / Includes bibliographical references (leaves : 52-53).

This work presents a novel means of producing thin-film light-emitting devices, functioning according to the principle of electroluminescence, using an inkjet printing technique. This study represents the first report of a light-emitting device deposited completely by inkjet printing. An electroluminescent species, doped zinc sulfide, was incorporated into a polymeric matrix and deposited by piezoelectric inkjet printing. The layer was printed over other printed layers including electrodes composed of the conductive polymer poly(3,4-ethylenedioxythiophene), doped with poly(styrenesulfonate) (PEDOT:PSS) and single-walled carbon nanotubes, and in certain device structures, an insulating species, barium titanate, in an insulating polymer binder. The materials used were all suitable for deposition and curing at low to moderate (<150°C) temperatures and atmospheric pressure, allowing for the use of polymers or paper as supportive substrates for the devices, and greatly facilitating the fabrication process. The deposition of a completely inkjet-printed light-emitting device has hitherto been unreported. When ZnS has been used as the emitter, solution-processed layers have been prepared by spin-coating, and never by inkjet printing. Furthermore, the utilization of the low-temperature-processed PEDOT:PSS/nanotube composite for both electrodes has not yet been reported. Device performance was compromised compared to conventionally prepared devices. This was partially due to the relatively high roughness of the printed films. It was also caused by energy level misalignment due to quantization (bandgap widening) of the small (<10 nm) nanoparticles, and the use of high work function cathode materials (Al and PEDOT:PSS). Regardless of their reduced performance, inkjet printing as a deposition technique for these devices presents unique advantages, the most notable of which are rapidity of fabrication and patterning, substrate flexibility, avoidance of material wastage by using drop-on-demand technology, and the need for only one main unit operation to produce an entire device.

This work presents a novel means of producing thin-film light-emitting devices, functioning according to the principle of electroluminescence, using an inkjet printing technique. This study represents the first report of a light-emitting device deposited completely by inkjet printing. An electroluminescent species, doped zinc sulfide, was incorporated into a polymeric matrix and deposited by piezoelectric inkjet printing. The layer was printed over other printed layers including electrodes composed of the conductive polymer poly(3,4-ethylenedioxythiophene), doped with poly(styrenesulfonate) (PEDOT:PSS) and single-walled carbon nanotubes, and in certain device structures, an insulating species, barium titanate, in an insulating polymer binder. The materials used were all suitable for deposition and curing at low to moderate (<150°C) temperatures and atmospheric pressure, allowing for the use of polymers or paper as supportive substrates for the devices, and greatly facilitating the fabrication process. The deposition of a completely inkjet-printed light-emitting device has hitherto been unreported. When ZnS has been used as the emitter, solution-processed layers have been prepared by spin-coating, and never by inkjet printing. Furthermore, the utilization of the low-temperature-processed PEDOT:PSS/nanotube composite for both electrodes has not yet been reported. Device performance was compromised compared to conventionally prepared devices. This was partially due to the relatively high roughness of the printed films. It was also caused by energy level misalignment due to quantization (bandgap widening) of the small (<10 nm) nanoparticles, and the use of high work function cathode materials (Al and PEDOT:PSS). Regardless of their reduced performance, inkjet printing as a deposition technique for these devices presents unique advantages, the most notable of which are rapidity of fabrication and patterning, substrate flexibility, avoidance of material wastage by using drop-on-demand technology, and the need for only one main unit operation to produce an entire device.

The Swedish Environment Protection Act (SEPA) was implemented in 1969 and constituted the first comprehensive Swedish regulation of industry-induced environmental externalities. In keeping with a longstanding corporatist tradition, Swedish policymakers aimed to establish a cooperative climate with industrial producers and instructed the regulatory authorities to strive to reach consensual agreements with affected firms. Despite such accommodations, the environmental adaptation of Swedish industrial production proceeded at a greater pace, during the 1970’s and 1980’s, than in most comparable countries, many of which had implemented seemingly more stringent environmental regulations than had Sweden. This thesis seeks to identify the firm level incentives behind this process, by examining the economic impact of the SEPA upon one of the more pollution-intensive branches of Swedish industrial production, the pulp and paper industry. Guided by previous research, an hypothesis is proposed in which the implementation of the SEPA came to aid the structural rationalization of this industry during the 1970’s and 1980’s, by inducing the exit of marginal, small-scale pulp and paper mills, thereby relaxing the prevailing competition over wood resources and available market space and creating more room for expansion within the surviving mills. As larger firms tend to operate larger mills, the hypothesized effects are suggested to have benefited large-scale producers within the industry, at the expense of their smaller rivals.   The findings of the thesis show that the economic effects of the SEPA were more severe for small as compared to large-scale mills and that regulatory requirements for pollution abatement did contribute to the shutdown of several small-scale mills during the 1970’s and 1980’s. No conclusive evidence could, however, be found for the validity of the thesis’ hypothesis as a whole, as these shutdowns were not predominantly administered by small-scale firms, as predicted by the hypothesis. Rather, the vast majority of these shutdowns were accounted for by some of the largest firms within the industry. Some tentative evidence was found, however, that the implementation of the SEPA may have benefitted certain large-scale producers within the industry, by facilitating acquisitions of smaller firms with valuable assets.

Diss. (sammanfattning) Stockholm : Tekn. högsk., 2004. / Härtill 7 uppsatser. I häftet felaktigt ISBN: KTH/FTP/R--2004/37--SE.

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 146-152). Also available in electronic format on the Internet.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references (p.97-102).