This thesis has been performed at Mondi kraft pulp and paper mill located in Sweden, Kramfors Dynäs due to the low return rate of condensate. Currently, the return rate is only at 65 - 75 %. This is problematic as the demineralization process is operating on full capacity and thus requires a reduced make-up water need. The production of demineralized water is an expensive process due to large requirements of chemicals and pump-energy, but also due to the cost of raw water and maintenance. Therefore the purpose of the work was to investigate the possibility to increase the condensate return rate and thus reduce the need of make-up water. The investigation was performed during normal production rates to simplify the interpretations. The steam and condensate system was mapped and extracted flows were identified, measured and marked on map. The extracted flows were investigated in more detail and characterized as either consumed in a process or lost to sewer or atmosphere. In the work, both minor and major improvements were investigated. Minor improvements are accomplished with small intervention measures and could be done with small or no investments costs. Major improvements require large investments costs and further investigations. Six different processes were found to constitute the total production of make-up water. These are the free blowing of excess steam, soot blowing steam, paper machine 6, de-aerating process in the feed water tanks, digester process and steam- & condensate leaks along the pipe network. Improvements with the category of minor were found to reduce steam and condensate consumption by 22 - 23 ton/h. This implies a reduction by 30 - 32 % of the added make-up water, including an annual financial benefit of 3,3 - 3,9 MSEK. Additionally 0,41 - 0,82 MSEK could be gained annually by improving the insulation on the cylinder dryer heads. The make-up water would be further reduced if insulation jackets and inspection programs were implemented on equipments along the steam lines. Two major improvements are recommended. The first major improvement involves elimination of the free blowing of excess steam. This could be accomplished by drying the bark before combustion. The added make-up water would be reduced by 25 % and with the possibility to sell the dried bark during low steam production. The second major improvement involves the digester process, where the consumptions of medium pressure steam could be reduced by replacing steam with liquor-steam from the strong liquor accumulator. Medium pressure steam could instead be converted into electricity by the turbine.

The effects of UV pretreatment on alkaline bleaching (EOP) wastewater from a kraft pulp and paper mill were investigated prior to anaerobic digestion (AD) in an upflow anaerobic sludge blanket (UASB) reactor. The aim was to enhance the methane production, increase the reduction of total organic carbon (TOC) and determine the best UV exposure time. The exposure time of 2.6 minutes partially degraded the organic material in the EOP wastewater since it generated higher biogas and methane production than the reference period, while it also increased the reductions of solved chemical oxygen demand (CODsol) and TOCsol. The exposure time of 16 minutes, on the other hand, did not show any significant improvement regarding increased biogas and methane production nor did it increase the reduction of CODsol. However, it did increase the reduction of TOCsol, but not to the same extent as the exposure time of 2.6 minutes. The presence of unwanted microbial growth in the system during the experiment might have affected the effectiveness of the UV pretreatment more during the exposure time of 16 minutes as the amount of growth was more substantial during this period of time. Furthermore, no optimal exposure time could be determined due to lack of time.

This research followed acetate carbon (C) uptake, metabolism, and fate through a typical modern Kraft pulp and paper mill AS system. Freshly collected mill biomass (AS floc suspensions) was placed under conditions representing four key phases of AS biotreatment: (1) initial acetate uptake by aerated starved AS; (2) ongoing acetate uptake; (3) aerobic metabolism of acetate-loaded AS in acetate-stripped effluent; and (4) anaerobic, settled biomass metabolism. Conditions mimicked the mill system as closely as possible. Acetate carbon uptake kinetics and conversion to CO2, growth products, PHB, and secreted metabolites in each of the four phases were measured. The role of PHB synthesis in the initial stripping of acetate from mill effluent and the PHB production potential of this mill AS were also investigated. / Results showed that acetate was rapidly taken up by high-affinity systems in the AS. During the initial exposure of mill-starved AS, acetate greatly stimulated AS-O2 uptake, and was quickly converted to PHB and CO 2. Upon depletion of available effluent acetate, as occurs in the downstream sections of the aeration tank, O2-uptake rates decreased and the acetate-C stored in AS-PHB was slowly released as CO2, and partly used for growth. Under secondary clarifier-like anaerobic conditions, the AS released virtually no CO2. However, substantial amounts of PHB were used for growth under anaerobic conditions and a small proportion of the original acetate C exited the cells as organic acids.

One of the problems encountered in paper converting is caused by the occurrence of "baggy webs", which essentially is when the tension profile of the paper web is uneven. In an area with low tension the paper is longer, which results in bagginess. The baggy parts can not usually be stretched to even out the tension of the paper web in a converting machine, with the result that runnability problems are likely to occur. The aim of the work described in this thesis was to investigate three particular stages in papermaking, namely drying, calendering and storage, and rank them according to their propensity for inducing baggy webs. The focus was placed on investigating the effects of uneven moisture and grammage profiles on the machine-direction strain difference profile. The largest strain difference occurred when there were systematic thick streaks throughout a reel that formed ridges. Stress relaxation during storage then gave rise to a difference in strain of 0.14% when the ridge height was around 2-3 mm. Thickness variations due to variations in grammage is also a source of moisture variation. A difference in moisture of 5% in the calendering stage resulted in strain differences of about 0.05-0.08%. These strain differences resulted in creases being formed as early on as in the calender nip when differences in both grammage and moisture content were present. Most creases appeared when the moisture difference was 2-8%. The difference in grammage could be large without creases being formed when no differences in moisture content were present. A moisture difference of about 5-6% during drying resulted in a strain difference of 0.1% measured on isotropic samples. The moist area turned into a tight streak when the moisture difference appeared at moisture contents higher than 25%. At moisture contents lower than 20%, on the contrary, the moist area turned into a slack streak. The conclusion drawn is that papermakers should concentrate first and foremost on eliminating variations in grammage, especially if these are systematic. This would also eliminate some variations in moisture content, which would solve more problems.

In this thesis I argue that science fiction is not a genre exclusively made up of written texts but a community or series of communities. I examine the science fiction community's engagement with questions of femeninity, masculinity, sex and sexuality over the past seventy years, that is from 1926 until 1996. My examination of this engagement is centred on the battle of the sexes, the lives of James Tiptree, Jr. and the Award named in Tiptree's honour. I make connections between contemporary feminist science fiction and the earliest pulp science fiction engagements with sex and sexuality.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Lorraine York. Includes bibliographical references (leaves 277-287).

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Lorraine York. Includes bibliographical references (leaves 277-287).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Dissertation (M.Sc. (Chemical engineering)) -- University of Pretoria, 2008. / Includes bibliographical references (p. 42-52)