Dissertations / Theses: 'Wood-pulp'

1

Poirier, Nicole A. "Displacement washing of wood pulp." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65442.

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2

Hosseinkhani, Marandi Behzad. "Assessment of wood pulp fibres using labelled enzymes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62914.pdf.

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3

Bennington, Chad Patrick Joseph. "Mixing pulp suspensions." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28622.

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Initiation and maintenance of motion within a pulp suspension is necessary for effective mixing. This requires imposition of forces greater than the network strength and depends on suspension rheology once motion begins. As pulp suspensions display non-Newtonian and solid-like behaviour, studies were conducted using profiled rotors which imposed stress within the body of suspensions contained in cylindrical devices. A concentric cylinder device capable of high torques (85 N-m) and high rotational speeds (524 rad/s) was built to study pulp suspension dynamic behaviour. Most work used a profiled rotor 0.1 m in diameter with baffled housings 0.13 and 0.22 m in diamter. The yield stress of low consistency pulp suspensions were measured with a Haake RV12 Ro-tovisco concentric cylinder viscometer. Semi-bleached kraft pulp was used throughout the study. Some tests were made with stone groundwood and thermomechanical pulps. Yield stress measurements were made for nylon and Spectra-900 fibre suspensions. The yield stress of pulp suspensions, ty, have been measured and correlated with mass concentration (Cm) and volumetric concentration (Cv) over the range 0.4 ≤ Cm(%) ≤ 33. It was found that because of increasing gas content that correlations developed using the mass concentration were inaccurate above approximately 20% Cm. Correlations developed using the volumetric concentration were accurate over the full range tested. For a West-Coast semi-bleached kraft pulp, ty(Pa) = 1.40CV(%)²ֹ⁷². Once rotor motion was initiated, pulp suspensions exhibited two distinct regimes of behaviour. The first was a tangential-cavity regime in which predominantly tangential motion grew to fill the chamber as shear rate increased. When motion reached the outer housing wall a flow transition occurred, likely triggered by flow interaction with the housing baffles. The subsequent post-transition regime was characterized by radial and axial flow that effectively mixed the suspension on both the macroscale and fibre-scale. The flow transition appeared to be what earlier workers reported as the onset of "fluidization". During tangential-cavity flow, phase segregation occurred. Gas present in the suspension collected around the rotor and reduced momentum transfer from the rotor to the suspension. This caused the torque for the pulp suspension to fall below that for water at the same rotational speed, and the cessation of flow development in the chamber. If sufficient momentum transfer was attained to initiate post-transition flow, the chamber contents became effectively mixed. The torque could still fall below that of water depending on the effective density of the suspension in the rotor vicinity.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

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4

Tunc, Mehmet Sefik. "Relationship between Alkaline Pulp Yield and the Mass Fraction and Degree of Polymerization of Cellulose in Pulp." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/TuncMS2003.pdf.

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5

Violette, Steven M. "Oxygen Delignification Kinetics and Selectivity Improvement." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/VioletteSM2003.pdf.

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6

Deshpande, Sagar Nandkumar. "Pre-hydrolysis of the Phenyl Glycosidic Bond in a Model Compound." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/DeshpandeSN2008.pdf.

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7

Lee, Oh-Kyu. "Mechanistic Studies of the Oxidation of Lignin and Cellulose Models." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/LeeO2002.pdf.

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8

Baker, Scott Alan. "Activated sludge biotreatability of pulp and paper bleach wastes : investigation of bleaching options." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/21647.

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9

Forde, Kohler Lois J. "The effects of ophiostoma piliferm on wood pulp : investigation." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/5982.

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10

Patterson, Shane. "The agronomic benefit of pulp mill boiler wood ash." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61322.pdf.

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11

Patterson, Shane, and University of Lethbridge Faculty of Arts and Science. "The agronomic benefit of pulp mill boiler wood ash." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2001, 2001. http://hdl.handle.net/10133/127.

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Land application of wood ash is becoming more appealing, as a disposable alternative, to landfilling options. It is estimated that 110,000 tonnes of wood ash is produced annually in Alberta by cogeneration systems, a large percentage produced in Central and Peace River Regions of Alberta. Alkaline (pH-13) properties and nutrient content of wood ash provides an alternative for the acidic and nutrient deficient soils within these regions. The objective of this field study was to determine the effect wood ash applications would have under field conditions on: the chemical and physical properties of soils; barley dry matter production; grain and seed yield of barley and canola; and the nutrient and metal uptake by crop tissue. Ash applications significantly increased dry matter and seed yield, improved crop nutrient quality, increased soil pH and improved soil nutrient availability, while not infringing on any environmental regulations.
xxiii, 142 leaves : ill. ; 28 cm.

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12

López-Dellamary, Fernando A. "Surface modification of pulp fibers with amino acids for Zwitterionic bonding /." Thesis, Connect to this title online; UW restricted, 1991. http://hdl.handle.net/1773/5568.

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13

Smith, Robert James. "Oxidative extraction of chlorinated pulp in a packed bed reactor." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/10265.

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14

Hsu, Chieh-Lung Jay. "Mass transfer and kinetics in oxygen delignification of wood pulp." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/10965.

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15

Scheepers, Gerhardus C. (Gerhardus Coenraad). "Enzymatic pitch control in the kraft pulping and bleaching of Eucalyptus spp." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51745.

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Thesis (MSc)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: The extractive materials in wood often cause pitch problems in pulp mills. During pulping and bleaching extractives are released from the wood and pulp and later stick to ceramic and metal parts, forming pitch deposits. Pitch deposits impair both product quality and production rates. It decreases the efficiency of pulp washing, screening, centrifugal cleaning, and refining, and can disrupt many paper machine operations. The deposits also break loose from equipment and cause spots in the final product. There are a few triggering mechanisms that induce pitch deposition. Hydrodynamic or mechanical shear can destabilise the colloidal pitch emulsion, causing pitch to agglomerate and deposits to form. Similarly, sudden temperature drops and/or pH shocks and/or the introduction of water hardness ions from fresh water inlets or showers can also cause pitch deposits by destabilising the colloidal pitch emulsion. Inorganic salts, such as calcium carbonate, can catalyse pitch deposition by acting as the building blocks for the sticky pitch. Calcium ions in the white water can react with fatty acids, forming insoluble, sticky calcium soaps. Triglycerides have also been shown to be a major contributor to pitch deposition in kraft pulping and bleaching mills. It forms a sticky deposit to which less sticky particles attach. To attain an improved understanding of pitch problems associated with the kraft pulping and bleaching of Eucalyptus spp., various analyses were done on wood- and pulp extractives and pitch from a South African kraft pulp mill. High molecular weight compounds (involatile) constituted a large portion of the extracts and pitch. Approximately 40% of volatile Eucalyptus grandis extract was f3-sitosterol, with fatty acids (22.8%) and triglycerides (15.5%) also making a substantial contribution. Fatty acid amides were a prominent fraction of pulp extracts from the latter stages of bleaching. The amides constituted 38.3% and triglycerides 10.1% to total volatile pitch deposits. Lipases hydrolyse triglycerides and could therefore help to reduce pitch problems. Consequently 381 filamentous fungi isolated from indigenous and commercial forests in South Africa were screened for lipase activity on tributyrin and Tween 80. Eight strains were selected and the tributyrin and Tween 80 assays were repeated by monitoring lipase activity over a seven-day period. The selected strains were also assayed for their activity toward p-nitrophenyl palmitate. Ophiostoma piliferum Cartapip 58™ and Phanerochaete chrysosporium BKM-F-1767, two strains known for respectively their biodepitching and biopulping ability, were' used as controls. A few of the strains compared well and even outperformed the control strains, indicating their potential for use in pitch control. The effect of pretreatment with the eight selected fungal strains on E. grandis wood- and pulp extractives was determined. Cartapip 58™ and P. chrysosporium BKM-F-1767 were used as control strains. Several of the strains compared well to the control strains in their ability to reduce the triglyceride content of wood extract. The South African isolate, white-rot fungus Phanerochaete psuedomagnoliae nom. prov., reduced triglyceride content significantly. Consequently it can act as an agent for both biopulping and biodepitching. The treated wood samples had a lower triglyceride content than the sterile controls. Consequently more triglycerides would be released into process waters by the sterile controls than the treated samples. The effect of commerciallipases on deposited brown stock pulp extract was also evaluated. The lipases did not reduce the triglyceride content of the deposited extract. The addition of lipases in pulping and bleaching processes would therefore not affect already deposited pitch.
AFRIKAANSE OPSOMMING: Die ekstrakstowwe van hout veroorsaak dikwels 'n neerslag tydens verpulping. Gedurende verpulping en bleiking kom ekstrakstowwe van die hout enpulp vry en kleef aan keramiek- en metaalonderdele. Gevolglik benadeel dié neerslag produkkwaliteit en produksietempo. Dit verlaag die effektiwiteit van pulpwas, sifting, sentrifugale skoonmaakprosesse en suiwering, en kan die werkverrigting van papiermasjiene ontwrig. Die neerslag kan ook later los breek en kolletjies op die finale produk veroorsaak. Verskeie meganismes kan die neerslag veroorsaak. Hidrodinamiese of meganiese wrywing kan die kolloïdale ekstrakstofemulsie destabiliseer en sodoende die ekstrakstof laat konglomereer en neerslaan. Op soortgelyke wyse veroorsaak skielike temperatuurverlaging en/of pH-skokke en/of die toevoeging van ione in varswater om waterhardheid te beheer ook die neerslag deur die kolloïdale ekstrakstofemulsie te destabiliseer. Anorganiese sout soos kalsiumkarbonaat kan neerslagvorming kataliseer omdat dit optree as bousteen vir die klewerige, sementagtige ekstrakstowwe. Kalsiumione in die proseswater kan ook reageer met vetsure om onoplosbare, klewerige kalsiumsepe te vorm. Dit is bewys dat trigliseriede een van die hoofoorsake is in die vorming van die neerslag tydens kraft verpulpingen bleikingprosesse. Om die neerslagreaksie wat met die kraft verpulping en bleiking van Eucalyptus spp. geassosieer word, beter te verstaan, is verskeie analises op hout- en pulpekstrakte asook die neerslag van 'n Suid-Afrikaanse kraft verpulpingsaanleg uitgevoer. Hoë molekulêre massa (nie-vlugtige) stowwe het 'n groot gedeelte van die ekstrakte en neerslag uitgemaak. Ongeveer 40% van die vlugtige Eucalyptus grand is ekstrak bestaan uit ~-sitosterol met vet sure (22.8%) en trigliseriede (15.5%) wat ook aansienlike bydraes lewer. Vetsuuramiede verteenwoordig 'n beduidende komponent van pulpekstrak by die laaste stadiums van bleiking. Die amiede het 38.3% en trigliseriede 10.1%tot die vlugtige fraksie van die neerslag bygedra. Lipases hidroliseer trigliseriede en kan dus help om neerslagprobleme te voorkom. Gevolglik is 381 filamentagtige fungi geïsoleer uit inheemse en kommersiële woude van Suid-Afrika en hul lipase-aktiwiteit op tributyrin en Tween 80 geëvalueer. Agt rasse is geselekteer en die tributyrin en Tween 80 toetse is herhaal deur lipase-aktiwiteit oor 'n sewe-dag periode te monitor. Die geselekteerde rasse is ook getoets vir lipase-aktiwiteit met p-nitrofenielpalmitaat. Ophiostoma piliferum Cartapip 58™ en Phanerochaete chrysosporium BKM-F-1767, twee rasse wat daarvoor bekend staan vir onderskeidelik hul vermoë om houtekstrakstowwe te verminder en te bioverpulp, is as kontroles gebruik. 'n Paar van die geselekteerde rasse het goed vergelyk en selfs beter presteer as die kontrolerasse; 'n aanduiding van hul potensiaal om neerslagreaksies te beheer. Die effek van voorafbehandeling met die agt geselekteerde fungi rasse op E. grandis hout- en pulpekstrak is vasgestel. Cartapip 58™ en P. chrysosporium BKM-F-1767 is gebruik as kontrolerasse. Verskeie rasse het goed vergelyk met die kontrolerasse in hul vermoë om die trigliseriedinhoud van die houtekstrak te verlaag. Die Suid-Afrikaanse isolaat, witverrottingswam Phanerochaete pseudomagnoliae nom. prov., het ook die trigliseried inhoud beduidend verminder. Gevolglik sou dit as 'n middel kon dien vir beide neerslagvoorkoming en bioverpulping. Die trigliseriedinhoud van die behandelde monsters was laer as dié van steriele kontroles. Gevolglik sal meer trigliseriede in proseswater vrygestel word deur die steriele kontroles as die behandelde monsters. Die effek van kommersiële lipases op ongebleikte kraft pulpekstrakneerslag is ook geëvalueer. Omdat lipases nie die trigliseriedinhoud van die neerslag kon verlaag nie sal die gebruik van lipases dus nie die ekstrakstofneerslag in verpulpings- en bleikingsprosesse beïnvloed nie.

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16

Trummer, Joseph A. "Characterization of lignin reactions in buffered solvent pulping." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/10275.

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17

Faass, George Steven. "Development of a solvent pulping process." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/10931.

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18

DeLange, Michael Ferron. "Quantitative C-13 NMR of poplar lignins obtained from neutral solvent pulping." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/11192.

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19

Fraser, Donald Scott. "Fate and effects of pulp mill effluent solids in the soil environment." The University of Waikato, 2007. http://hdl.handle.net/10289/2621.

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The pulp and paper industry in New Zealand annually produces over one hundred thousand dry tonnes of solid waste due to the treatment of pulp and paper mill effluents, the majority of which is currently landfilled. The New Zealand Waste Management Strategy (2002) has set a target for the diversion of commercial organic wastes from landfill to beneficial use to exceed 95% by 2010 . Effluents produced by softwood pulp mills, such as in New Zealand, contain high concentrations of naturally derived resin extractive compounds that are toxic to fish and other aquatic organisms. Improvements in waste water treatment technology has enabled the industry to meet rigorous discharge standards, however, this has resulted in an increase in the production of pulp mill effluent solids which require disposal. This has become an issue for the pulp and paper industry, especially as current landfill space is limited. Land application has been used for many years as a means of disposal of pulp mill wastes. While most studies investigating land application of pulp mill effluent solids have concluded that the risk posed to the environment is low, few have investigated the potential toxicity of these wastes to soil organisms, and these studies did not directly address the effects of resin extractive compounds. Resin extractives have been shown to be recalcitrant and to accumulate in anaerobic sediments. It is not known to what extent resin extractives are bioavailable or degradable in land applied Pulp mill effluent solids (PMES), or their potential to bioaccumulate in soil organisms. This PhD thesis research sought to extend the knowledge on the environmental fate and effects of pulp mill effluent wastes. It focused on terrestrial systems, which have not been well studied in this respect. Four chemically distinct softwood pulp mill effluent solids, a primary treatment solid and three secondary treatment biosolids, were used to investigate their effects on soil organisms and soil functions. An interdisciplinary approach was adopted, which incorporated three main areas of study, as follows: 1. A comprehensive resin extractives analysis of the pulp mill effluent solids undertaken so that effects on soil organisms and soil functions could be related to the resin extractives chemistry of the individual pulp mill effluent solids tested. 2. A battery of bioassays used to investigate the toxicity of the selected pulp mill effluent solids. 3. A field trial set-up to investigate how pulp mill effluent solids affected soil functions and also to investigate the decomposition of pulp mill effluent solids and of resin extractives in these solids. Three hypotheses tested were: I. Pulp mill effluent solids are toxic to soil organisms. II. Resin extractives in pulp mill effluent solids are recalcitrant in the terrestrial environment. III. Pulp mill effluent solids will cause significant measurable negative impacts on soil functional capacity. A wide range of resin extractives compounds were identified in pulp mill effluent solids, and concentrations of individual compounds varied widely between the different pulp mill effluent solids tested. During the two years after field application of the pulp mill effluent solids, resin extractives declined, however, decay rates of individual compounds were variable. The decay rate of compounds was influenced by the type of pulp mill effluent solids containing these compounds and not by the initial concentration of compounds. All compounds, including resin acids, degraded rapidly in the applied primary solid and in one of the applied biosolids, with average half-lives calculated ranging from three to twelve months. In the other biosolids, resin acids were recalcitrant with average half-lives calculated to be nearly ten years. Laboratory bioassays conducted on oats, earthworms and enchytraeid worms indicated that pulp mill effluent solids had low toxicity to these organisms. An aquatic bioassay organism, however, was acutely affected by aqueous extracts from pulp mill effluent solids. Earthworms were shown to bioaccumulate some resin extractive compounds to a limited extent, indicating that resin extractives were bioavailable in pulp mill effluent solids. Enchytraeid reproduction was reduced by exposure to some pulp mill effluent solids but this was not correlated to resin extractives concentration of the solids tested. Field applied pulp mill effluent solids significantly enhanced the fluxes of CO2 from the soil surface. When mass losses of pulp mill effluent solids carbon were taken into account, it was shown that these solids had little effect on soil respiration. Needle litterbags were placed above and below pulp mill effluent solids and in the litter horizon of a control treatment for 12 months. Needle litter decomposition was not significantly different between treatments, however, changes in enzyme activities were detected in litter beneath pulp mill effluent solids compared to control needle litter that had not been exposed to pulp mill effluent solids. The decomposition rate of field applied pulp mill effluent solids was slow, with half-lives extrapolated to be between five and twenty five years. The decomposition rate appeared to be influenced by the pools of carbon available for decomposition, with primary solids decaying significantly faster than biosolids due to a higher cellulose component. The conclusions of the PhD thesis research are, therefore, that generally, pulp mill effluent solids used in the study were demonstrated to be relatively benign and appear to pose a low risk to the terrestrial ecosystem when applied to soil. However, a cautious approach is still recommended to land application, based on the extensive evidence of disruption to aquatic ecosystems, and because pulp mill effluent solids will take many years to decompose and resin acids are recalcitrant in some pulp mill effluent solids. Further research is recommended to elucidate mechanisms of action by resin extractives in soil organisms and the ultimate fate of these compounds in the soil compartment.

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20

Nilsson, David. "Prediction of wood species and pulp brightness from roundwood measurements." Doctoral thesis, Umeå : Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-605.

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21

Persson, Erik. "Storage of spruce pulpwood : effects on wood and mechanical pulp /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-6090-5.pdf.

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22

Sequeira, Anna J. "Analysis of wood pulp extracts utilizing gas chromatography-mass spectroscopy." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39964.

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23

Mji, N. (Ntuthuzelo). "Pressurised hot water extraction of wood : three wood species prior to pulping." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50423.

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Thesis (MSc)--Stellenbosch University, 2005.
No english abstract available.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van warm water uitloging van houtspaanders by hoë temperature en onder hoë druk voor alkaliese verpulping te ondersoek. Warm water uitloging van houtspaanders onder druk voor alkaliese verpulping was baie belowend, aangesien dit ekstrakstowwe verwyder het wat andersins verteringschemikalieë sou opgebruik het en ook verbertede verpulpingstoestande meegebring het. Gedurende uitloging het die houtstruktuur verander agv die verwydering van die ekstrakstowwe. Dit het veroorsaak dat die houtstruktuur meer toeganglik geword het, en dit het gelei tot 'n verbeterde diffusie van die kookloog. Die versnelde kookloogdiffusie het 'n verbeterde en meer gelykmatige delignifikasie meegebring. Warm water uitloging by verhoogde druk is ondersoek vir drie houtsoorte nl. Eucalyptus grandis, Acacia mearnsii en Pinus patuia. 'n Twee-uur en 'n een-uur uitlogingstyd van die houtspaanders voorafgaande Kraft en soda-AQ verpulping is ondersoek.Vergelyk met 'n een-uur uitloging is daar gevind dat die twee-uur uitloging van die houtspaanders te drasties was, met 'n gevolg van 'n vermindering in pulpopbrengs, vesellengte en pulpsterkte. Die verlaging III pulpsterkte kon toegeskryf word aan polisaggariedafbreking. Die een-uur uitloging het 'n hoër opbrengs opgelewer as beide die kontrole (nie uitgeloogde houspaanders) en die twee-uur uitgeloogde houtspaanders. Die een-uur uitlogingsperiode het besonder goeie verpulpingsresultate vir die ekstrakstofryke Acacia mearnsii houtspaanders getoon, met 'n bykomstige verbetering in pulpsterkte eienskappe.

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24

Jackson, Linda C. "Neutral solvent pulping product characterization." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/11234.

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25

Sugiharto, Andoyo. "The effect of chemical and xylanese pretreatment on the quality of softwood kraft pulp bleached with CED sequence." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/25316.

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Sinden, Jane. "The electrokinetic aspect of cellulose fibres used in the papermaking process." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244904.

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27

Krothapalli, Deep. "Gas-liquid Mass Transfer in Oxygen Delignification Systems." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/KrothapalliD2004.pdf.

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28

Siddiqui, Nazia. "Characterization of Mechanically and Enzymatically Produced Cellulose Nanofibers from Wood Pulp." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/SiddiquiN2008.pdf.

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29

Niemi, Jan. "Online characterization of wood pulp : foundations for a photoacoustic sensing technique /." Luleå : Department of Computer Science and Electrical Engineering, Luleå University of Technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3012484.

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30

Wamugunda, B. G. "Economic feasibility of a second pulpmill in Kenya." Thesis, Canberra, ACT : The Australian National University, 1987. http://hdl.handle.net/1885/130491.

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Kenya's forestry has passed through a long exploitation phase which involved the removal of most of the usable timber species followed with the introduction of fast growing exotic species. These offer an assured industrial base because of fast growth rates and are now supporting 1 pulp and paper mill, 4 plywood mills, 3 match factories, 1 particle board mill, 300 sawmills and 1 fibreboard mill. Current production of softwoods exceeds the industrial requirements of the country and a proposal to establish a second pulpmill to utilise excess softwoods was presented to the government a few years ago. This proposal was rejected on the understanding that there are no wood supplies. At the same time the Development Plan [1983-88] has proposed a paper and pulpmill under the Lake Basin Development Authority to utilise bamboo. In addition there are plans for expanding the existing pulpmill from the present production of 49,000 tonnes of pulp to 60,000 tonnes per year. Webuye pulp and paper mill was set up with hopes for enormous benefits for the country in the form of foreign exchange savings and export earnings. It appears to be failing in this because of its heavy foreign debts, capital intensity and the efforts of trying to meet all the paper needs of the country, resulting in inefficient operations. The demand unsatisfied by Webuye cannot justify a second pulp mill which could only depend on a regional rather than a Kenyan market to realise enough economies of scale. Tanzania has established a large Kraft mill which is already in trouble over lack of markets, Malawi is planning a large mill to utilise its large supplies of pines and the region generally does not have as healthy a market for paper products as envisaged years ago. Pursuit of industries for their own sake has influenced many industries in Kenya in the past and a second pulpmill is seen as part of an international concert in industrial financing in some low income countries. Some of these industries have had little regard for the socio-economic conditions existing in the countries and have resulted in economic harm rather than the cure expected. The Kenyan economy is quite promising currently but most rural and urban poor continue to be marginalised by industries that do not take their lot into consideration. A second pulp mill for Kenya fails in improving the foreign exchange position, balance of payments, terms of trade, employment opportunities, contribution to equality and income distribution and most socio-economic "attributes" of industrialisation.

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31

Barzyk, David. "Topochemical and performance aspects of fiber oxidation." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/7010.

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32

Ashok, Kumar. "Passage of fibres through screen apertures." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30849.

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Passage of fibres suspended in water through apertures of dimensions greater than a fibre length and less than a fibre diameter has been examined at flow conditions approximating those in a pulp screen (large velocity parallel to the wall upstream of the aperture compared to the flow velocity within the aperture). Fibre behaviour was characterized in terms of three components: penetration of the leading tip into the aperture, rotation of the fibres on the downstream edge of the aperture, and fibre bending. Dimensionless numbers for each of these factors were derived from simple mass and force balances of fibres at an aperture entry. Experimental measurements of the magnitude of fibre passage were made on a single aperture located in a flow channel and in multiple apertures in a device simulating a commercial pulp screen in cross-section. For stiff fibres, it was found that fibre passage changed greatly with the ratio of fibre length to aperture width (L/W). When L/W was less than 2, the relationship between fibre passage and aperture velocity was approximately an exponential curve. The passage data correlated well with the penetration parameter. On the other hand, when L/W > 2, up to measured values of L/W = 6, the relationship between fibre passage and aperture velocity corresponded to a cumulative probability distribution curve. This latter behaviour, and the absence of a correlation with penetration and rotation parameters, was ascribed to contact between the tip of the rotating fibre and the upstream wall of the aperture. This was confirmed by experimental observations. Flexible long (L/W > 2) fibres showed behaviour between the two cases described above. The above observations were found to hold qualitatively for elevated concentrations up to a crowding factor of 4, multiple apertures, and the presence of pulses induced by a rotor of the type found in pulp screens. Accordingly, it appears that the findings are likely to hold in pulp pressure screens. An implication of this finding is that long stiff fibres may be best separated from short ones by choosing an aperture size such that L/W > 2 for the long fibre fraction and < 2 for the short fibre fraction.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

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33

Ji, Yun. "Kinetics and Mechanism of Oxygen Delignification." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/JiY2007.pdf.

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34

Sweeney, Renee Marie. "Investigation of the effect of neutral solvent pretreatment of tulip poplar on enzymatic hydrolysis." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/10013.

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35

Rodriguez, Reynaldo A. "Improving fiber yield by reducing pulping knots." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/10289.

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36

Agarwal, Niraj. "Modeling of continuous pulping /." Thesis, Connect to this title online; UW restricted, 1993. http://hdl.handle.net/1773/5564.

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37

Mortyn, Joel William. "Economic analysis of recovering solid wood products from western hemlock pulp logs." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/4912.

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The purpose of this research was to quantify what value could be gained from cutting solid wood products from old-growth western hemlock (Tsuga heterophylla (Raf.) Sarg.) logs that are used to produce pulp in British Columbia. These logs represent a significant portion of the resource and increasing their value recovery would be beneficial to the forest industry. One hundred and sixteen logs were sampled from the coastal and interior regions of British Columbia. Dimension and quality attributes were measured to enable estimates of gross and merchantable volume. Logs deemed likely to yield lumber were sawn with the aim of maximizing value recovery. The nominal dimension and grade of all lumber recovered was recorded. Margins and breakpoints at which sawing became profitable were calculated. Models to predict the volume of lumber and proportion of Clear grade lumber recovered (“C Industrial” grade at the interior mill, “D Select” grade at the coastal mill) were developed. Lumber recovery, especially Clear grade lumber, was significantly higher from logs from the coastal site. At current market prices, cutting lumber from these logs was profitable, with the highest margins achieved when chips were produced from the milling residue. It was not profitable to recover lumber from the interior logs regardless of whether chips were produced. The disparity between locations was attributed to differences between the logs, the sawmilling equipment, the sawyers’ motivations and the lumber grades. Between 60% and 67% of coastal logs and 13% to 21% of interior logs returned a profit, depending on whether chips were produced. Models were developed to better identify these logs using observable attributes. A linear model described the total volume of lumber recovered. Significant predictor variables in the model were the gross log volume, the average width of the sound collar and the stage of butt/heart rot at the large end. A second model predicted the proportion of Clear grade lumber. Regional models were developed to account for different Clear lumber grades between sawmills. Significant predictor variables were knot frequency, diameter at the large end, volume, length, taper and the width of the sound collar at the large end.

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38

Iwamoto, Shinichiro. "Nano-fibrillation of wood pulp for the utilization in optically transparent nanocomposites." Kyoto University, 2008. http://hdl.handle.net/2433/136610.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第13883号
農博第1698号
新制||農||954(附属図書館)
学位論文||H20||N4350(農学部図書室)
UT51-2008-C799
京都大学大学院農学研究科森林科学専攻
(主査)教授矢野浩之, 教授川井秀一, 教授杉山淳司
学位規則第4条第1項該当

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39

Widiatmoko. "Oxygen delignification process chemistry for Acacia." Thesis, Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-10212006-130331/.

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40

Dang, Zheng. "Pulp Pretreatments for Improved Selectivity and Extended Oxygen Delignification." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/DangZ2002.pdf.

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41

Hanley, Shaune J. (Shaune John). "Application of atomic force microscopy to cellulose, wood, kraft pulp fibres and paper." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40030.

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The surfaces of well characterised microfibrils from Ventricaria and Micrasterias denticulata (M.d.), wood sections, kraft pulp fibres and paper have been examined with both atomic force microscopy (AFM) and Tapping Mode atomic force microscopy (TM-AFM), under ambient conditions in both air and water. Artifacts and limitations inherent to these techniques in the study of microfibrils, pulp fibres and paper are discussed. AFM images of the surface of the highly crystalline cellulose microfibrils, Ventricaria and M.d., were obtained at molecular resolution under ambient conditions; the molecular images showed periodicities along the microfibril axis that correspond to those of the fibre and glucose unit repeat distances of cellulose, respectively. Images of the section surface of Black Spruce (Picea mariana) wood clearly show features of the underlying cell wall structure. The apparent lamellation, with periodicities from tens or nanometers down to 15 nm, were observed in radial sections of the middle secondary wall (S2). However, transverse sections of the same S2 layer did not show a lamellation independent of the knife direction. AFM images of unbeaten and beaten unbleached kraft pulp fibre surfaces indicate the orientation of the component microfibrils; fibrillar material attached to the surface of the beaten fibres was readily observed. Images from the scale of the fibre web down to the microfibril level in air and water show the dimensional changes of the paper surface and fibres. However, little or no change was seen at the microfibril level. The dimensions of the lamella in wood sections and the size of the microfibrils at both the surface of pulp fibres and the fibrillated material indicate that microfibrils as small as 1.5 nm across are present.

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42

Reme, Philip André. "Some effects of wood characteristics and the pulping process on mechanical pulp fibres." Doctoral thesis, Norwegian University of Science and Technology, Department of Chemical Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1774.

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The thesis comprises three parts: Existing methods for characterisation of fibre crosssections have been improved, and new methods have been developed. These methods have then been applied to study the effects of wood characteristics and the pulping process on mechanical pulp fibres. Links have been established between fibre structure and paper properties such as surface smoothness and light scattering coefficient.

New methods, based on SEM-images and image analysis, are described for providing cross-sectional fibre dimensions for large fibre populations, for wood tracheids (app. 60 000 tracheids in a wood trunk) and for processed pulp fibres (app. 1000 fibres per sample). The methods are suited e.g. for evaluation of changes in the fibre cross-sections from wood to the finished paper, or for mapping of fibre parameters within and between growth rings in a wood trunk. The treatment of data is discussed, showing how one may examine the changes in different groups of fibres (earlywood fibres, latewood fibres, split fibres) throughout a process.

It is known from the literature that groundwood-based paper is superior to TMP-based paper with respect to printability. Fibres from SGW and PGW-pulp were found to be much more split in the longitudinal direction than TMP-fibres at comparable freeness. Intact groundwood fibres had thicker walls than intact TMP-fibres, but nevertheless super calendered hand sheets made from groundwood fibres were less roughened by moistening than were TMP-based sheets. Both for groundwood pulps and for TMPpulps, it was shown that reduced fibre wall thickness and increased fibre splitting was beneficial for improved surface smoothness and opacity.

Latewood defibrate easier than earlywood during refining. In the case of grinding, there was no particular preference for earlywood or latewood to be defibrated. Reject refining of groundwood reject was, however, found to be very important for defibration of latewood-containing shives. Pulps made from a raw material with more compact fibres (high wall area to lumen area ratio) were found to defibrate easier, and contain less shives. It was found that refining tends to reduce wall thickness most on thickwalled parts of the fibre, thus causing a reduction of the wall thickness variation around the perimeter.

Earlywood fibres were found to be preferentially split during refining. Most fibre splitting occurs during the primary stage, while the fibres are firmly attached to chips or fibre bundles. Latewood fibre wall thickness decreases considerably more than earlywood fibre wall thickness during refining. It seems that choosing an appropriate raw material is more effective than using excessive energy on reducing the wall thickness of thickwalled fibres. Earlywood fibres became more flattened during refining compared to latewood fibres, possibly due to repeated compressions and relaxations in the refiner.

The energy consumption to a given freeness was found to be considerably larger for Scots Pine than for Norway Spruce. However, the fibre transverse dimensions did not differ much between Norway Spruce and Scots Pine. Pine pulps were far less developed than spruce pulps at similar energy level. A possible explanation for the large energy consumption may be that redistribution of extractives at the fibre surface could reduce friction in the refiner. This hypothesis should be further explored.

The results in this study improve the knowledge of which fibre parameters that matter for surface smoothness and opacity of wood-containing publication paper. Further, this study elucidates how important fibre parameters such as wall thickness and fibre splitting are altered during a refining process. The results may be utilized to identify possible ways of modifying the TMP-process in order to produce paper with improved surface smoothness and opacity.

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43

Suren, Aydin. "Scaling of black liquor in falling film evaporator." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/10147.

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44

Bakke, Bruce W. "Reduction of sulfur release through indigester oxidation in kraft pulping." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/11691.

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45

Liu, Yue. "Application of secondary fluorescence to measure the kappa number of single fibers /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/5478.

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46

Louro, Graça Maria Cabaço. "Modelo global para as fileiras silvo-lenhosas." Doctoral thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/3873.

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Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia
The production flows in the sector of wood construction and furniture, paper and paper board and that of wood, paper and paper board wrapping and packaging sector are analyzed. The macroeconomic indicators associated with them are characterized, showing their importance in the Portuguese national economy. The characteristics of the corresponding enterprises and workforce, as well as the main domestic and international market trends for the different phases of the productive cycle are described. The recent evolution of wood production from maritime pine (Pinus pinaster Aiton) and eucalyptus (Eucalyptus globulus) is described and analyzed in a context that takes in account their potential to supply raw material for wood based industries. The effect of forest fire regimes and cuts on wood availability is modeled, using National Forest Inventories data and wildfire statistics. The models were used in predictions of future wood availability under various fire scenarios. Models for the supply and domestic consumption of sawn wood, wood panels, wood pulp, and paper and paper board, based on econometric equations, were developed.

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47

Klein, Stephen Richard. "A regional analysis of supply in the Canadian pulp and paper sector." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24826.

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The purpose of this thesis was to analyse the supply of pulp and paper products in the three major producing provinces of Canada, namely British Columbia, Ontario and Quebec. A translog restricted profit function and its first partial derivatives were estimated using the iterative seemingly unrelated regressions procedure. Derived demand equations for energy, fibre, labour and supply equations for net market pulp, newsprint and 'other paper and paperboard", (net market pulp and 'all paper and paperboard' for British Columbia) were obtained with net supplies as a function of each input and output price. The success of the model in representing the industry was mixed. Derived demand own price elasticities were, in almost all cases, negative as expected a priori. Negative own price elasticities were also found in many end product supply functions suggesting a misspecification of the supply relationship. The unexpected supply function results bring up questions about the degree of competitiveness in pulp and paper markets, and thus the validity of using the perfectly competitive market assumption in empirical studies. Finally the model was evaluated in the context of using the results in a spatial equilibrium model of the North American pulp and paper sector.
Forestry, Faculty of
Graduate

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48

Hart, Peter W. "Formation and release of adsorbable organic halogens during kraft pulp bleaching." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/11219.

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49

Brancato, Adam Anthony. "Effect of progressive recycling on cellulose fiber surface properties." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26504.

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Thesis (Ph.D)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Sujit Banerjee; Committee Member: Frances Walsh; Committee Member: Peter Ludovice; Committee Member: Timothy Patterson; Committee Member: Yulin Deng. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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50

Fortin, Nathalie. "Molecular characterization of dechlorination potential in kraft pulp mill effluent treatment systems." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27317.

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Many low molecular weight chlorinated organic compounds produced by the pulp and paper industry during kraft bleaching of the wood pulp are toxic. Mass balance studies suggest that mineralization of chlorinated organics is occurring in pulp and paper mill wastewater treatment systems. To understand the nature of dechlorination activity, molecular tools such as oligonucleotide primers and corresponding DNA probes were developed to monitor the presence of microorganisms possessing key genes (dehalogenases) responsible for the degradation of chloroaliphatic organics in kraft pulp mill effluent treatment systems. Oligonucleotide primers designed from the coding sequence of known dehalogenases and a methane monooxygenase gene, which is known to catalyze dehalogenation reactions, were used for polymerase chain reaction (PCR) analysis, using genomic DNA extracted from dehalogenating bacterial isolates and total community DNA extracted from water and sediments of lagoon treatment systems. PCR amplification with dhlB oligonucleotide primers, designed from the haloacid dehalogenase of Xanthobacter autotrophicus, revealed the presence of dehalogenase genes in both aerated lagoons and stabilization basins. Similar results were obtained with mmoX primers designed from the methane monooxygenase gene of Methylococcus capsulatus. DNA sequence analysis of several PCR fragments showed significant similarity to known dehalogenase genes. The molecular tools developed in this study revealed the presence of different types of microorganisms with dechlorination potential in the microbial community of pulp mill effluents.

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Dissertations / Theses on the topic 'Wood-pulp'

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