Massatvätt är ett viktigt steg i kraft-processen, då kokkemikalierna kan återvinnas och återanvändas i processen, vilket minimerar belastningen på miljön. Det är ett viktigt steg innan blekning av massan, då en låg kemisk syre-förbrukning (COD) är viktigt för att minska förbrukning av blekningskemikalier. Dessutom kan massatvätt även eliminera andra oönskade material, såsom metaller eller extraktivämnen. Syftet med studien var att utvärdera av tvätt-effektivitet av industriell massatvätt. Målen var att jämföra industriell tvättning med extensiv tvättning, att undersöka kvaliteten av tvättvätskor med analystekniker och att undersöka befintliga metoder för att beräkna tvätt-effektivitet. Den experimentella fasen var indelad i provtvättning och tvätt-serier, utförda med olika tvättvätskor, uppehållstider och industriell och extensiv utspädningsfaktor. Provtvättningen gav resultat som möjliggjorde det att utveckla tvätt-metoden. Resultaten för tvätt-serien visade att den extensiva utspädningsfaktorn generellt gav bättre resultat och en mer effektiv tvätt, och att en tvättvätska med en temperatur på 80°C generellt gav bättre resultat. Ljusheten påverkades inte av utspädningsfaktorn och kappanalysen visade en väldigt liten skillnad jämfört med originalmassan. Utvärderingen av befintliga metoder för att beräkna tvätt-effektivitet indikerade att alla undersökta metoder kunde ge felaktiga resultat, men beräkningarna tillsammans med andra metoder såsom COD, konduktivitet och med flera borde ge industrin en god indikation på tvätt-effektiviteten / Pulp washing is an important step in the kraft process, as it allows for the cooking chemicals to be recovered and reused in the process, which also minimizes the environmental load to the subsequent stages. It is also important before the bleaching plant, as a low chemical oxygen demand (COD) carry-over is important to minimize the consumption of bleaching chemicals. Furthermore, washing can also remove other unwanted materials, such as metals or wood extractives. The aim of the study was to assess washing efficiency of industrial washing. The objectives were to compare industrial washing with extensive washing, to investigate the quality of wash liquors using analytical techniques and to examine existing methods for calculating washing efficiency. The experimental phase was divided into trial washing and washing series, conducted with different wash liquors, residence times and dilution factors (DF). The trial washing yielded results that allowed for the washing methodology to be improved. The results from the washing series indicated the extensive DF in general gave better results and provided a more efficient washing, and that a wash liquor of 80°C gave better results. Brightness was not affected by the dilution factor and kappa number analysis showed that there was a very slight difference compared to the original pulp. The evaluation of existing methods for calculating washing efficiency indicated that all investigated methods could give inaccurate results, but that the calculations together with other methods such as COD and conductivity should give the industry a good indication of the washing efficiency.

Dissertation submitted in fulfilment of the requirements for the Degree of Masters in Technology: Business Administration, Durban University of Technology, 2013. / Leadership is defined as a process by which an individual attempts to influence other group members towards achieving group goals. Leadership is also viewed as a process which people use to bring out the best in themselves and others. National culture is said to play a pivotal role in determining the effectiveness of leadership styles. Literature on leadership identifies transformational leadership, transactional leadership and laissez-faire leadership as the three common leadership styles in the current climate, with transformational leadership and transactional leadership being the most dominant. Literature suggests that an employee’s job satisfaction is strongly influenced by leadership style. Current leadership styles are related to job satisfaction by varying degrees. Several studies have indicated that transformational leadership results in higher levels of job satisfaction than transactional or laissez-faire leadership. The overall aim of the study was to investigate the relationship between leadership styles and employee job satisfaction levels within the organisation. A quantitative study was conducted to accomplish the objectives of the study. Questionnaires were administered to employees within the selected target population in the organisation. The data received were analysed using statistical packages. The results of the study show that there are statistically significant relationships between overall transactional leadership and job satisfaction, overall transformational leadership and job satisfaction and laissez-faire leadership and job satisfaction. However, two attributes of transformational leadership best explain job satisfaction. Intellectual stimulation contributed most to explaining job satisfaction, followed by individualised consideration. The remaining attributes of transformational leadership, transactional leadership and laissez-faire contribution to job satisfaction.

Die Entdeckung adulter dentaler Stammzellen eröffnete ein neues Forschungsfeld im Hinblick auf die Regeneration dentaler Gewebe. Bisher liegen nur wenige Studien vor, in denen das Genexpressionsprofil dentaler Stammzellen im Vergleich zu den Knochenmarkstammzellen analysiert wurde. Diese Untersuchungen wurden vorwiegend an Mischkulturen vorgenommen. Im Gegensatz dazu war es daher das Ziel der vorliegenden Arbeit, das Genexpressionsprofil einer bestimmten Stammzell-Population, nämlich der Stro1-positiven pulpalen mesenchymalen Zahnkeimstammzellen (Stro1+ZK) im Vergleich zu Stro1-positiven mesenchymalen Knochenmarkstammzellen (Stro1+BK), zu untersuchen. Die Genexpression beider Zelltypen wurde anhand von Microarrays ermittelt. Insgesamt gingen 22.454 Gene in die Auswertung ein, wovon bei einem konservativ festgesetzten Schwellenwert einer FDR≤1% 2730 Gene eine hochsignifikant differentielle Expression zeigten. Die Analyse dieser differentiell exprimierten Gene mithilfe der Programme „DAVID“ und „Ingenuity“ ergab, dass in den Stro1+ZK vermehrt Gene heraufreguliert sind, die mit Zellfunktionen wie beispielsweise Proliferationsregulation, der Zell-zu-Zell-Signalleitung und der Organisation des Zytoskeletts verknüpft sind. Die Stro1+BK hingegen exprimieren verstärkt Gene, die mit der Organisation der extrazellulären Knochenmatrix und Zell-Adhäsion assoziiert sind. Des Weiteren findet sich in diesen Zellen eine verstärkte Expression von Genen, die mit der Struktur- und Formgebung des Skeletts in Verbindung stehen. Trotz identischem Stammzellmarker-Typus (Stro1) weisen die untersuchten mesenchymalen Stammzelltypen stark unterschiedliche Hox-Gen-Signaturen auf. Dabei zeigt sich sowohl eine Variation in Anzahl und Art der Hox-Gene als auch in deren Expressionsmuster. Stro1+BK exprimieren verstärkter Hox-Gene der Cluster A bis D (HOXA-D), die Segment- und Positionsinformationen codieren. Hingegen sind in den Stro1+ZK die Hox-Gene BARX1, MSX1, MSX2, DLX1, DLX2, PAX9 und LEF1 hochreguliert, welche eine tragende Rolle in der Zahnentwicklung spielen. So ist z.B. bereits bekannt, dass Mutationen dieser Gene zu Fehlbildungen von Zähnen wie Aplasien oder Hypoplasien führen können. Die vorliegende Arbeit zeigt, dass insbesondere hinsichtlich der Hox-Gene signifikante Unterschiede zwischen den Stro1+ZK und Stro1+BK bestehen. Weiterführende Experimente zur Aufklärung der Funktionsweise von Genen, die in den Stro1+ZK von Bedeutung sein könnten, einschließlich deren Erforschung auf proteinbiochemischer und zellbiologischer Ebene, wären wünschenswert.

SCA Östrand implements an expansion of its current production of pulp. Today's 435 000 tonnes will be 900 000 tonnes when the new production line is put into operation in 2018. SCA Logistics, which is responsible for the storage and transportation of pulp would therefore like to know how much area that is currently storing pulp and if the existing surface is sufficient to cope with the increase in volume from SCA Östrand. If the surface is not enough, SCA Logistics want to know how much space will be needed to cope with the increase in volume. The study is a combined case study and design methodology. Through process mapping, various scenarios are being developed to implement the current status and future analysis where the purpose of the study can be determined by calculating the maximum area, volume and fill rate. Information has been obtained from printed literature, scientific papers, previous theses, and observations of the process in SCA Logistics in the port of Tunadal. Relevant data has been obtained from an external supervisor at SCA Logistics. The study provides answers to how much space is available at present time, the fact that the current surface will not be sufficient to cope with the increase in volume and a minimum of additional 5800 m2 surface area will be needed to store pulp on. / SCA Östrand genomför i dagsläget en expansion av dess nuvarande produktion av pappersmassa. Dagens 435 000 ton kommer dubbleras när den nya produktionslinjen tas i bruk 2018. SCA Logistics som ansvarar för lagring och transportering av pappersmassan vill således veta hur mycket yta som finns i nuläget att lagra pappersmassa på och om den befintliga ytan är tillräcklig för att klara av volymökningen från SCA Östrand. Om ytan inte räcker till, vill SCA Logistics veta hur mycket yta som kommer behövas för att klara av volymökningen. Studien är en kombinerad fallstudie och designmetodik. Genom en processkartläggning kommer olika scenarion tas fram för att genomföra en nuläges-och framtidsanalys där syftet med studien kommer bestäm-mas genom att beräkna maximal area, volym och fyllnadsgrad. Inform-ation införskaffas från tryckt litteratur, vetenskapliga artiklar, tidigare examensarbeten, samt processpromenader på SCA Logistics i Tunadals-hamnen. Relevant data erhålls från extern handledare på SCA Logistics. Studien ger svar på hur mycket yta som finns tillgängligt i nuläget, att denna yta inte kommer vara tillräcklig för att klara av volymökningen och ett minimum av ytterligare 5800 m2 behövs utöver den nuvarande ytan som finns tillgänglig.

No description available.

The production of pulp and paper is associated with the generation of large quantities of wastewater that has to be purified to avoid severe pollution of the environment. Wastewater purification in pulp and paper mills combines sedimentation, biological treatment, chemical precipitation, flotation and anaerobic treatment, and the specific combination of techniques is determined by the local conditions. Wastewater treatment generates large volumes of sludge that after dewatering can be incinerated and thus used for bio-energy production. Sludge is currently viewed as biofuel of poor quality due to its high water content, and some mills treat it solely as a disposal problem. Two strategies have been identified as feasible options to improve the energy efficiency of sludge management. One is drying using multi-effect evaporation followed by incineration. The other is anaerobic digestion of the wet sludge to produce methane. This thesis explores the energy balances of sludge management strategies in pulp and paper mills with special focus on anaerobic digestion. The first part consists of a system analysis, used to evaluate some wastewater treatment processes and sludge management, and the second part of empirical studies of anaerobic digestion of pulp and paper mill sludge. It was shown that the use of energy for aeration in aerobic biological treatment should be kept to the minimum required for acceptable quality of the processed water. Additional aeration for reduction of the generated sludge will only result in reduced energy generation in a subsequent methane generation stage. In the second part of the thesis, it is shown that anaerobic digestion is a feasible option for sludge management as it leads to production of high value biogas. Co-digestion with grass silage, cow/pig manure or municipal sewage sludge should then be used to counteract the low nitrogen content of pulp and paper mill sludge.

Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The distribution of different free chemical functional groups on wood and pulp fibres was determined by means of atomic force microscopy (AFM) with chemically modified tips. Because these functional groups show a higher affinity to similar groups on the substrate surface during scanning, AFM images were recorded using an additional digital pulsed-force mode (DPFM) controller. This allowed the distribution of the chemical components to be imaged and to a degree, also to be quantified. The investigated tip coatings showed different sensitivities towards the major chemical components present in wood fibres. These components were determined on spin-coated films as well as wood fibres. It was possible to make a clear distinction between cellulose and lignin in both cases. This technique could therefore be used to differentiate between cellulose and lignin present on pulp fibre surfaces and to confirm the successful removal of lignin by pulping. The chemical composition of wood fibres and fibre surfaces of several acacia and eucalyptus species, and hybrids originating from various growth sites in South Africa, are compared. The objective was to determine the differences in chemical surface composition due to genetics or site. The motivation for this was to eventually facilitate a tailor-made supply of wood for pulping which results in an optimal blend of fibres that can be pulped together with similar yields. This, however, first requires a sound knowledge of the fibre properties. The surface functionality on the single fibre level is a key property because it determines how good inter-fibre bonding will be when paper is formed, which in turn depends to a large degree on the amount of free hydroxyl groups that are available and therefore on the cellulose content on the fibre surface. The cellulose and lignin contents on the fibre surface were determined with chemical force microscopy (CFM), a variation of AFM. CFM involves the use of chemically modified tip using selected functional groups. Since, the general bulk composition of the fibre and the surface composition differ, both parameters were determined. Significant differences in the cellulose and lignin content on fibre surfaces were found, with regard to genotype and site, respectively. In some, but not all, cases the surface composition of wood fibres followed the bulk composition and differences were generally more pronounced. Differences due to genotype were significant, especially with regards to the surface lignin content - but variation due to site was also distinctly recognisable. This variation in surface functionality could be the reason why some pulpwood blends result in a lower pulp yield and different quality. / AFRIKAANSE OPSOMMING: Die verspreiding van verskillende vrye chemiese funksionele groepe op hout en pulpvesels is bepaal deur middel van atoomkragmikroskopie (AFM), met chemies-gemodifiseerde punte (tips). Omdat hierdie funksionele groepe 'n hoër verwantskap tot soortgelyke groepe op die substraat se oppervlak gedurende skandering toon, kan AFM-beelde wat met 'n addisionele digitalepulskragmodusbeheerstel bepaal word dit moontlik maak om die verspreiding van die chemiese komponente uit te beeld en tot op ‘n sekere vlak te kwantifiseer. Die ondersoekte punt-oppervlakmiddels het verskillende sensitiwiteite teenoor die hoof chemiese komponente in die houtvesels en spin-bestrykte films getoon. 'n Duidelike onderskeid kon in beide gevalle tussen sellulose en lignien gemaak word. Hierdie tegniek kon dus gebruik word om te onderskei tussen sellulose en lignien wat op die pulpveseloppervlak teenwoordig was en om die suksesvolle verwydering van lignien gedurende die pulpproses (pulping) te bevestig. In hierdie studie is die chemiese samestelling van houtvesels en die veseloppervlaktes van verskeie akasia en eucalyptus spesies, asook dié van gekruisde spesies wat van verskeie werfliggings in Suid-Afrika afkomstig is, vergelyk. Die doel was om te toets vir verskille in chemiese oppervlaksamestellings, wat veroorsaak kan word deur genetika of werf verskille, met die uiteindelike mikpunt om ‘n spesiaal-gemaakte voorraad van hout vir pulping te fasiliteer, wat kan lei tot 'n optimale mengsel van vesels wat saam gepulp kan word met soortgelyke opbrengs. Dit vereis natuurlik 'n goeie kennis van die veseleienskappe. Die oppervlakfunksionering van enkel vesels is ‘n kritiese eienskap omdat dit bepaal hoe goed interveselverbindings sal wees wanneer papier gevorm word. Dit hang tot ‘n groot mate af van die hoeveelheid vry hydroksielgroepe wat beskikbaar is en dus ook van die sellulose inhoud op die veseloppervlak. Die sellulose- en lignieninhoud op die veseloppervlak is bepaal met chemiese kragmikroskopie – 'n variasie van atoomkragmikroskopie. Omdat die algemene grootmaat samestelling van die vesel en die oppervlaksamestelling mag verskil, is altwee parameters bepaal. Beduidende verskille in die sellulose- en lignieninhoud, met betrekking tot genotipe en werfligging, op veseloppervlaktes is gevind. In sommige, maar nie alle, gevalle het die oppervlaksamestelling van houtvesels ooreengestem met die grootmaatsamestelling, en verskille was oor die algemeen meer beduidend. Verskille as gevolg van genotipe was beduidend, veral met betrekking tot die oppervlak lignieninhoud, maar variasie as gevolg van werfligging was ook duidelik herkenbaar. Hierdie variasie in oppervlakfunksionering kan die rede wees hoekom sommige pulp–hout mengsels lei tot 'n laer pulpopbrengs en verskille in kwaliteit.

No description available.

Thesis (PhD)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: White rot fungi are of interest in the paper and pulp industry because of their removal of lignin from wood. In this study over 600 Basidiomycete fungi were isolated from indigenous forests as well as from commercial Eucalyptus spp. and Pinus spp. plantations in South Africa. One hundred isolates were identified to genus level. Biochemical tests were done to screen the fungal cultures for characteristics that are favourable for biopulping, e.g. low cellulase activity with concomitant high activity of ligninolytic enzymes. Various Phanerochaete isolates with potentially high ligninolytic activity were identified. Although Phanerochaete chrysosporium Burds. has previously been isolated from the indigenous forest at Knysna in South Africa, this study showed that P. chrysosporium was a natural coloniser of wood chip piles in South Africa, indicating potential for application in industry. A possible new species of Phanerochaete, viz. Phanerochaete pseudomagnoliae nom. provo (strain PP25) from decayed wood collected in Stellenbosch, South Africa, was described and illustrated. It differs from previously described Phanerochaete species in having smaller basidiospares, and in the formation of few chlamydospores on malt extract agar but more on xylose containing media. The potential of using internal transcribed spacer DNA sequences (ITS) to infer phylogenetic relationships among species of the genus Phanerochaete was investigated. Consensus phylogenetic trees could be presented, but the presence of ambiguous aligning sequences within the ITS made inferring of phylogenetic relationships within the whole genus difficult. Fifty-five South African strains of P. chrysosporium were screened for lignin peroxidase (liP), manganese peroxidase (MnP) and glyoxal oxidase (GLOX) enzymes. Manganese peroxidase activity was quantified on agar media. The liP and GLOX activities of 13 selected strains, including control strains and P. pseudomagnoliae (PP25), were also quantified on agar media. Differences in MnP and GLOX activities existed among the strains. Preliminary biochemical characterisation of strain PP25 indicated that the most important difference was the apparent unique regulation of ligninolytic enzymes. Under low nitrogen, liP activity of the selected strains showed no significant variation, whereas strain PP25 had significantly increased liP levels under high nitrogen conditions. Restriction fragment length polymorph isms of the lignin and manganese peroxidase gene DNA fragments showed variability among strains, whereas there was probably only allelic variation for the glox gene DNA fragments. Previous research has indicated xylose oxidation activity within P. chrysosporium. To investigate whether GLOX can oxidise xylose, a purified recombinant GLOX (rGLOX) from P. chrysosporium BKM-F-1767 Burds. was used in this study. This rGLOX oxidised D-xylose and D-glucose (D-xylose > D-glucose) to produce H202. Xylose was oxidised to xylono-1 ,4-lactone with a 1:1 stoichiometric relationship between H202 produced and xylose used. Xylono-1,4-lactone was converted non-enzymatically to xylonate. This suggested that the furanose form of xylose, rather than the pyranose form, is a substrate of GLOX. The production of H202 and the removal of inhibitory compounds by GLOX could enhance ligninolytic activity. . To conclude, unique strains of P. chrysosporium have been isolated from South Africa with potential biotechnological use in paper manufacturing. The relationship of P. pseudomagnoliae nom. provo to other Phanerochaete species was evaluated and light was shed on the possible role of GLOX in lignin degradation. / AFRIKAANSE OPSOMMING: Witvrot swamme is van belang vir die papier en pulp industrie omdat hulle lignin vanaf hout kan verwyder. Meer as 600 Sasidiomiseet fungi, afkomstig vanaf inheemse woude asook kommersiële Eucalyptus spp. en Pinus spp. plantasies, IS geïsoleer. Een honderd isolate is tot op genusvlak geïdentifiseer. Die isolate is biochemies vir eienskappe wat voordelig vir "bioverpulping" kon wees, bv. die gelyktydige produksie van lae sellulosemaar hoë ligninolitiese ensiemaktiwiteit, getoets. Verskeie isolate met potensieel hoë vlakke van ligninolitiese aktiwiteit is verkry. Alhoewel Phanerochaete chrysosporium Surds. vantevore in die Knysna inheemse woud in Suid-Afrika geïsoleer is, het hierdie studie gewys dat P. chrysosporium natuurlik op hope houtblokkies voorgekom, met moontlike toepasing in die industrie. Isolaat PP25, geisoleer vannaf verrottende hout te Stellenbosch, Suid Afrika, is as 'n potensieel nuwe spesie van die genus Phanerochaete beskryf en as Phanerochaete pseudomagnoliae nom. provo benoem. Hierdie isolaat verskil van ander Phanerochaete-spesies daarin dat dit kleiner basidiospore vorm en nie klamydospore op moutekstrakagar produseer nie, maar wel op media wat xilose bevat. Die potensiaal van intern getranskribeerde spasieerder ONS opeenvolging vir die aflei van filogenetiese verhoudings tussen spesies van die genus Phanerochaete is ondersoek. Konsensus filogenetiese bome kon bepaal word, maar die teenwoordigheid van varieerbare areas het die afleiding van filogenetiese verwantskappe vir die hele genus bemoeilik. Vyf-en-vyftig Suid-Afrikaanse isolate van P. chrysosporium is vir die teenwoordigheid van lignienperoksidase- (liP), mangaanperoksidase- (MnP) en glioksaaloksidase (GLOX)-aktiwiteit getoets. Vlakke van MnP-aktiwiteit is op agarplate gekwantifiseer. Vlakke van LiP- en GLOX-ensieme op agarplate is vir 13 geselekteerde isolate, insluitend kontroles en ras PP25, gekwantifiseer. Aktiwiteit van MnP en GLOX het statisties betekenisvol tussen isolate verskil. Lignienperoksidase-aktiwiteit onder lae stikstof toestande het nie statisties betekenisvol van mekaar verskil nie. Onder hoë stikstof toestande het isolaat PP25 wel verhoogde liP-aktiwiteit getoon. Restriksie fragment polimorfismes van die lignien- en mangaanperoxidase-gene het variasie getoon, terwyl waarskynlik slegs alleliese variasie vir die glox geen waargeneem IS. Rekombinante GLOX (GLOX vanaf P. chrysosporium BKM-F-1767) het xilose en glukose (D-xilose > D-glukose) geoksideer met meegaande produksie van H202. Xilose is na xilono-1,4-laktoon geoksideer met 'n 1:1 stoigiometrie tussen H202-produksie en xilose verbruik. Xilono-1,4-laktoon is nieensiematies na xilonaat omgeskakel. Bogenoemde resultaat dui aan dat die furanose vorm van xilose die werklike substraat vir GLOX is. Deur die meegaande produksie van H202 en die verwydering van inhiberende produkte word lignoliese aangehelp. Ten slote, unieke P. chrysosporium rasse met potensiële gebruik in papiervervaardiging is in Suid-Afrika geisoleer. Die genetiese diversiteit van 'n nuwe spesie, P. pseudomagnoliae, is bepaal en nuwe lig is op die potensiële rol van GLOX in lignienafbraak gewerp.

published_or_final_version / Dentistry / Master / Master of Dental Surgery