O trabalho foi desenvolvido com o objetivo de caracterizar e estudar formas de tratamento de águas residuárias de indústrias de refino de óleo lubrificante e de recuperação de solventes. A fase preliminar teve por objetivo avaliar a biodegradabilidade do despejo combinado dessas duas indústrias. A segunda foi realizada em instalação piloto composta, basicamente, de uma unidade de arraste com ar/tanque de equalização, tanques de correção de pH e de aeração com tempos de detenção distintos, seguidos de tanques de sedimentação. Foram executados testes para avaliar a remoção de material solúvel em n-hexano do despejo da indústria de refino de óleo lubrificante e do efluente final. A unidade de arraste com ar difuso operando com subpressão de 15 mmhg a saída dos gases, vazão específica de ar de 20 ml/l min. E tempo de detenção de 5 dias foi eficiente na remoção de acetona, piridina, benzeno, tolueno, hexano, metil etil cetona e provavelmente solventes clorados. Não apresentou remoção significativa de álcoois, que foram eficientemente degradados no sistema biológico subsequente. Obteve-se remoções superiores a 90%, em termos de dbo e dqo, no processo biológico com tempos de detenção de 20 e 30 dias, e em torno de 80% para os demais. Os sistemas biológicos responderam bem as cargas transientes de solventes, exceto para o tolueno e o álcool isopropílico. / Traditionally, raw materials from solvent recovery and from reclaimed lubricating oil industries are considered hazardous solid waste. Consequently, the best control technology is incineration. This work was developed in order to characterize and to study ways of treating wastewaters from lubricating oil refinery and solvent recovery industries. The experimental part was divided in two phases. The preliminar step aimed to evaluate the biodegradability of combined wastewater from both industries. The second phase was basically carried out in a pilot plant composed by an air stripping unit/equalization tank, pH correction tanks and bioreactors with different retention times, followed by sedimentation tanks. Other than these assays, tests were performed to evaluate the removal of soluble material in n-hexane of the wastewater of the lubricating oil refinery industry and of the supernatant of the sedimentation tank after the bioreactor of 20 days retention.The buble aeration unit operating with a 15 mmHg suppresion to the gas exit, with a specific air flow of 20 mL/L.min. and with a retention time of 5 days was efficient to remove acetone, pyridine, benzene, toluene, hexane, methyl ethyl ketone and probably chlorinated solvents. There was no significative removal of alcohols, that were efficiently degraded in the subsequent biological system. BOD and COD removal efficiencies were better than 90% in the biological process with retention times of 20 and 30 days, and about 80% for the rest. The responses of biological systems to the transient inputs of solvents were well, except for toluene and isopropilic alcohol. Several physico-chemical processes for soluble material in n-hexane removal were studied. The only one to present effluent concentration under the legal limit was the addition of the sodium xylene-sulphonate base demulsifier to the supernatant of the sedimentation tank the bioreactor of 20 days retention.

<p>The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. The produced TMPs were thoroughly characterised in order to explain the effect of the chemical system on fibre development and to be able to propose a mechanism for the impact on refining energy reduction. The possibility to improve the optical properties by washing, chelating and sodium dithionite or hydrogen peroxide bleaching the treated pulps was evaluated.</p><p> </p><p>The results obtained in a pilot plant trial show that it is possible to significantly reduce the comparative specific energy consumption by approximately 20% and 35% at a freeness value of 100 ml CSF or a tensile index of 45 Nm/g by using 1% and 2% hydrogen peroxide respectively. The energy reduction is obtained without any substantial change in the fractional composition of the pulp, though tear strength is slightly reduced, as are brightness and pulp yield. No major differences between the reference pulp and the chemically treated pulps were found with respect to fibre length, width or cross-sectional dimensions. However, the acid hydrogen peroxide-treated pulps tend to have more collapsed fibres, higher flexibility, a larger specific surface area and a lower coarseness value. The yield loss accompanying the treatment is mainly a consequence of degraded hemicelluloses. It was also found that the total charge of the chemically treated pulps is higher compared to the reference pulps, something that may have influenced the softening behaviour of the fibre wall.</p><p> </p><p>A washing or chelating procedure can reduce the metal ion content of the chemically treated TMPs considerably. The amount of iron can be further reduced to a level similar to that of untreated pulps by performing a reducing agent-assisted chelating stage (QY) with dithionite. The discoloration cannot, however, be completely eliminated. The brightness decrease of the treated pulps is thus not only caused by higher iron content in the pulp, but is also dependent on the type of iron compound and/or other coloured compounds connected with the acid hydrogen peroxide treatment. Oxidative bleaching with hydrogen peroxide (P) is more effective than reductive bleaching with sodium dithionite in regaining the brightness lost during the energy reductive treatment. Using a QY P sequence, a hydrogen peroxide charge of 3.8% was needed to reach an ISO brightness of 75% for the chemically treated pulps. The corresponding hydrogen peroxide charge for the untreated TMP reference was 2.5%.</p><p> </p><p>The radicals generated in the Fenton reaction will probably attack and weaken/soften the available outer fibre wall layers. This could facilitate fibre development and consequently lower the electrical energy demand for a certain degree of refinement.</p>

<p>Neutralsulfitkokning av björk möjliggör ett högt utbyte av hemicellulosa, vilket bidrar positivt till flutingens egenskaper och minskar vedkostnaden. Neutralsulfitkoket ska avbrytas när delignifieringen nått tillräckligt långt för att veden ska kunna defibreras skonsamt med en rimlig energiinsats, men innan nedbrytningen av hemicellulosa hunnit accelerera. Syftet med detta examensarbete var att undersöka utbytets och malningens inverkan på NSSC-massans egenskaper.</p><p>En laboratoriestudie genomfördes där massan kokades till olika utbyten och maldes vid olika insatser. Resultatet av den studien användes sedan för att ställa om kokaren och raffinörerna på lämpligt sätt vid fabriksförsöken. Massaprover togs ut efter det andra kvarnsteget och skickades för analys. De mest väsentliga egenskaperna för fluting testades genom CCT (Corrugated Crush Test), CMT (Concora Medium Test) och SCT (Short Span Compression test) men övriga konventionella egenskaper testades likväl. En avgörande egenskap för fluting är också dess krypstyvhet som undersöktes på laboratorie genom isokrona kryptester. För att få en djupare förståelse för NSSC-massans egenskaper samt kokningens och malningens inverkan på dessa utfördes även fiberkaraktärisering.</p><p>Resultatet visar att styrkan på NSSC-massan kan påverkas genom att variera både utbytet och effekten i raffinörerna. För att åstadkomma en signifikant styrkeökning krävs ett lågt utbyte tillsammans med en hög effekt i raffinörerna. Kraftiga ändringar av dessa parametrar leder dessvärre till att papperets egenskaper förändras i den grad att körbarheten på maskin kan påverkas. Studien visar även att fluting som uppfyller dagens riktvärden kan framställas kostnadseffektivt genom ett högt utbyte i kokaren och en hög insats i raffinörerna. Samtidigt erhålls då en ljusare massa, vilket kan vara betydande i vissa fall. Krypmätningarna visar samtidigt att malningen i positiv bemärkelse påverkar krypstyvheten medan utbytets inverkan är mer svårtolkat. Ett allt för högt utbyte verkar dock vara negativt ur krypstyvhetssynpunkt.</p> / <p>Neutral sulphite cooking of birch enables a high yield of hemicelluloses. This contributes positively to the properties of the flute, reduces the amount of wood needed and hence the cost. The neutral sulphite cook is to be terminated when the delignification has gone sufficiently far so that the wood can be refined mercifully with a reasonable energy input, but before the delignification has gone so far that the degradation of hemicelluloses has started to accelerate. The objective with this thesis was to examine how yield and refining affects the properties of the NSSC pulp.</p><p>A laboratory study was performed where the pulp was cooked to different yields and then beaten with different energy inputs. The results from this study were then used to determine how to set the boiler and the refiners appropriately in the paper mill trials. Pulp samples were collected after the second refiner and were then sent for analysis. The most important properties for flute were tested through CCT (Corrugated Crush Test), CMT (Concora Medium Test) and SCT (Short Span Compression test). More conventional properties were tested as well. Another important property for flute, the creep resistance, was tested in the laboratory through isochronous creep tests. To get a deeper understanding of the properties of NSSC-pulp, along with the effects of cooking and refining, fiber characterization was also performed.The results indicate that it is possible to affect the strength properties on the NSSC pulp by varying both the yield and the energy input in the refiners. To accomplish a large increase in strength, a relatively low yield is needed, along with increased refining. Large changes of those parameters may unfortunately lead to changes in paper properties in such a way that the runability on the paper machine is affected.</p><p>The results also indicate that it is possible to manufacture flute in a more cost efficient way by lowering the H-factor in the boiler while increasing the degree of refining, still keeping the strength properties above the critical values.A pulp with a higher brightness is also acquired when running the mill this way, which can be important in some aspects. The creep studies indicate that increased refining has a positive effect on the creep resistance. It is harder to make conclusions about the impact of yield, but it seems as though all too high yields affects the creep resistance negatively.</p>

The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. The produced TMPs were thoroughly characterised in order to explain the effect of the chemical system on fibre development and to be able to propose a mechanism for the impact on refining energy reduction. The possibility to improve the optical properties by washing, chelating and sodium dithionite or hydrogen peroxide bleaching the treated pulps was evaluated.   The results obtained in a pilot plant trial show that it is possible to significantly reduce the comparative specific energy consumption by approximately 20% and 35% at a freeness value of 100 ml CSF or a tensile index of 45 Nm/g by using 1% and 2% hydrogen peroxide respectively. The energy reduction is obtained without any substantial change in the fractional composition of the pulp, though tear strength is slightly reduced, as are brightness and pulp yield. No major differences between the reference pulp and the chemically treated pulps were found with respect to fibre length, width or cross-sectional dimensions. However, the acid hydrogen peroxide-treated pulps tend to have more collapsed fibres, higher flexibility, a larger specific surface area and a lower coarseness value. The yield loss accompanying the treatment is mainly a consequence of degraded hemicelluloses. It was also found that the total charge of the chemically treated pulps is higher compared to the reference pulps, something that may have influenced the softening behaviour of the fibre wall.   A washing or chelating procedure can reduce the metal ion content of the chemically treated TMPs considerably. The amount of iron can be further reduced to a level similar to that of untreated pulps by performing a reducing agent-assisted chelating stage (QY) with dithionite. The discoloration cannot, however, be completely eliminated. The brightness decrease of the treated pulps is thus not only caused by higher iron content in the pulp, but is also dependent on the type of iron compound and/or other coloured compounds connected with the acid hydrogen peroxide treatment. Oxidative bleaching with hydrogen peroxide (P) is more effective than reductive bleaching with sodium dithionite in regaining the brightness lost during the energy reductive treatment. Using a QY P sequence, a hydrogen peroxide charge of 3.8% was needed to reach an ISO brightness of 75% for the chemically treated pulps. The corresponding hydrogen peroxide charge for the untreated TMP reference was 2.5%.   The radicals generated in the Fenton reaction will probably attack and weaken/soften the available outer fibre wall layers. This could facilitate fibre development and consequently lower the electrical energy demand for a certain degree of refinement.

The main objective of this thesis was to improve the understanding of some aspects on wood and fibre mechanics related to conditions in the thermomechanical pulping process. Another objective was to measure the power distribution between the rotating plates in a refiner.   The thesis comprises the following parts: –A literature review aimed at describing fracture in wood and fibres as related to the thermomechanical pulping process –An experimental study of fracture in wood under compression, at conditions similar to those in feeding of chips into preheaters and chip refiners –An experimental study of the effect of impact velocity on the fracture of wood, related to conditions of fibre separation in the breaker bar zone in a chip refiner –A micromechanical model of the deterioration of wood fibres, related to the development of fibre properties during the intense treatment in the small gap in the refining zone –Measurements of the power distribution in a refiner.   The fracture in wood under compression was investigated by use of acoustic emission monitoring. The wood was compressed in both lateral and longitudinal directions to predict preferred modes of deformation in order to achieve desired irreversible changes in the wood structure. It was concluded that the most efficient compression direction in this respect is longitudinal. Preferable temperature at which the compression should be carried out and specific energy input needed in order to achieve substantial changes in the wood structure were also given.   The fibre separation step and specifically the effect of impact velocity on the fracture energy were studied by use of a falling weight impact tester. The fracture surfaces were also examined under a microscope. An increase in impact velocity resulted in an increase in fracture energy. In the thermomechanical pulping process the fibres are subjected to lateral compression, tension and shear which causes the creation of microcracks in the fibre wall. This damage reduces the fibre wall stiffness. A simplified analytical model is presented for the prediction of the stiffness degradation due to the damage state in a wood fibre, loaded in uni-axial tension or shear. The model was based on an assumed displacement field together with the minimum total potential energy theorem. For the damage development an energy criterion was employed. The model was applied to calculate the relevant stiffness coefficients as a function of the damage state. The energy consumption in order to achieve a certain damage state in a softwood fibre by uniaxial tension or shear load was also calculated. The energy consumption was found to be dependent on the microfibril angle in the middle secondary wall, the loading case, the thicknesses of the fibre cell wall layers, and conditions such as moisture content and temperature. At conditions, prevailing at the entrance of the gap between the plates in a refiner and at relative high damage states, more energy was needed to create cracks at higher microfibril angles. The energy consumption was lower for earlywood compared to latewood fibres. For low microfibril angles, the energy consumption was lower for loading in shear compared to tension for both earlywood and latewood fibres. Material parameters, such as initial damage state and specific fracture energy, were determined by fitting of input parameters to experimental data. Only a part of the electrical energy demand in the thermomechanical pulping process is considered to be effective in fibre separation and developing fibre properties. Therefore it is important to improve the understanding of how this energy is distributed along the refining zone. Investigations have been carried out in a laboratory single-disc refiner. It was found that a new developed force sensor is an effective way of measuring the power distribution within the refining zone. The collected data show that the tangential force per area and consequently also the power per unit area increased with radial position. The results in this thesis improve the understanding of the influence of some process parameters in thermomechanical pulping related wood and fibre mechanics such as loading rate, loading direction, moisture content and temperature to separate the fibres from the wood and to achieve desired irreversible changes in the fibre structure. Further, the thesis gives an insight of the spatial energy distribution in a refiner during thermomechanical pulping.

Neutralsulfitkokning av björk möjliggör ett högt utbyte av hemicellulosa, vilket bidrar positivt till flutingens egenskaper och minskar vedkostnaden. Neutralsulfitkoket ska avbrytas när delignifieringen nått tillräckligt långt för att veden ska kunna defibreras skonsamt med en rimlig energiinsats, men innan nedbrytningen av hemicellulosa hunnit accelerera. Syftet med detta examensarbete var att undersöka utbytets och malningens inverkan på NSSC-massans egenskaper. En laboratoriestudie genomfördes där massan kokades till olika utbyten och maldes vid olika insatser. Resultatet av den studien användes sedan för att ställa om kokaren och raffinörerna på lämpligt sätt vid fabriksförsöken. Massaprover togs ut efter det andra kvarnsteget och skickades för analys. De mest väsentliga egenskaperna för fluting testades genom CCT (Corrugated Crush Test), CMT (Concora Medium Test) och SCT (Short Span Compression test) men övriga konventionella egenskaper testades likväl. En avgörande egenskap för fluting är också dess krypstyvhet som undersöktes på laboratorie genom isokrona kryptester. För att få en djupare förståelse för NSSC-massans egenskaper samt kokningens och malningens inverkan på dessa utfördes även fiberkaraktärisering. Resultatet visar att styrkan på NSSC-massan kan påverkas genom att variera både utbytet och effekten i raffinörerna. För att åstadkomma en signifikant styrkeökning krävs ett lågt utbyte tillsammans med en hög effekt i raffinörerna. Kraftiga ändringar av dessa parametrar leder dessvärre till att papperets egenskaper förändras i den grad att körbarheten på maskin kan påverkas. Studien visar även att fluting som uppfyller dagens riktvärden kan framställas kostnadseffektivt genom ett högt utbyte i kokaren och en hög insats i raffinörerna. Samtidigt erhålls då en ljusare massa, vilket kan vara betydande i vissa fall. Krypmätningarna visar samtidigt att malningen i positiv bemärkelse påverkar krypstyvheten medan utbytets inverkan är mer svårtolkat. Ett allt för högt utbyte verkar dock vara negativt ur krypstyvhetssynpunkt. / Neutral sulphite cooking of birch enables a high yield of hemicelluloses. This contributes positively to the properties of the flute, reduces the amount of wood needed and hence the cost. The neutral sulphite cook is to be terminated when the delignification has gone sufficiently far so that the wood can be refined mercifully with a reasonable energy input, but before the delignification has gone so far that the degradation of hemicelluloses has started to accelerate. The objective with this thesis was to examine how yield and refining affects the properties of the NSSC pulp. A laboratory study was performed where the pulp was cooked to different yields and then beaten with different energy inputs. The results from this study were then used to determine how to set the boiler and the refiners appropriately in the paper mill trials. Pulp samples were collected after the second refiner and were then sent for analysis. The most important properties for flute were tested through CCT (Corrugated Crush Test), CMT (Concora Medium Test) and SCT (Short Span Compression test). More conventional properties were tested as well. Another important property for flute, the creep resistance, was tested in the laboratory through isochronous creep tests. To get a deeper understanding of the properties of NSSC-pulp, along with the effects of cooking and refining, fiber characterization was also performed.The results indicate that it is possible to affect the strength properties on the NSSC pulp by varying both the yield and the energy input in the refiners. To accomplish a large increase in strength, a relatively low yield is needed, along with increased refining. Large changes of those parameters may unfortunately lead to changes in paper properties in such a way that the runability on the paper machine is affected. The results also indicate that it is possible to manufacture flute in a more cost efficient way by lowering the H-factor in the boiler while increasing the degree of refining, still keeping the strength properties above the critical values.A pulp with a higher brightness is also acquired when running the mill this way, which can be important in some aspects. The creep studies indicate that increased refining has a positive effect on the creep resistance. It is harder to make conclusions about the impact of yield, but it seems as though all too high yields affects the creep resistance negatively.

For paper producers, an understanding of the development of strength properties in the paper is of uttermost importance. Strong papers are important operators both in the traditional paper industry as well as in new fields of application, such as fibre-based packaging, furniture and light-weight building material. In the work reported in this thesis, three approaches to increasing paper strength were addressed: mixing different pulps, multilayering and reinforcement with man-made fibres. In specific: The effects of mixing Swedish softwood kraft pulp with southern pine or with abaca (Musa Textilis) were investigated. Handsheets of a softwood kraft pulp with the addition of abaca fibres were made in a conventional sheet former. It was seen that the addition of abaca fibres increased the tearing resistance, fracture toughness, folding endurance and air permeance. Tensile strength, tensile stiffness and tensile energy absorption, however, decreased somewhat. Still it was possible to add up to about 60% abaca without any great loss in tensile strength. As an example, with the addition of 30% abaca, the tear index was increased by 36%, while the tensile index was decreased by 8%. To study the effect of stratification, a handsheet former for the production of stratified sheets, the LB Multilayer Handsheet Former was evaluated. The advantage of this sheet former is that it forms a stratified sheet at low consistency giving a good ply bond. It was shown to produce sheets with good formation and the uniformity, evaluated as the variation of paper properties, is retained at a fairly constant level when the number of layers in the stratified sheets is increased. The uniformity of the sheets produced in the LB Multilayer Handsheet Former is generally at the same level as of those produced in conventional sheet formers. The effects of placing southern pine and abaca in separate layers, rather than mixing them homogeneously with softwood pulp were studied. Homogeneous and stratified sheets composed of softwood and southern pine or softwood and abaca were produced in the LB Multilayer Handsheet Former. It was found that by stratifying a sheet, so that a pulp with a high tear index and a pulp with a high tensile index are placed in separate layers, it was possible to increase the tear index by approximately 25%, while the tensile index was decreased by 10-20%. Further, by mixing a pulp with less conformable fibres and no fines with a pulp with more flexible fibres and fines, a synergy in tensile strength (greater strength than that predicted by linear mass fraction additivity) was obtained. The effects of stratifying sheets composed of softwood and abaca were compared to the effects of refining the softwood pulp. Homogeneous and stratified sheets composed of softwood with three different dewatering resistances and abaca were also produced in the LB Multilayer Handsheet Former. It was found that by stratifying the sheets the tear index was retained while the tensile index was increased by the refining. The effects of reinforcing softwood pulp of different dewatering resistances with man-made fibres with low bonding ability were also investigated. Man-made fibres (i.e. regenerated cellulose, polyester and glass fibres) were added in the amounts 1, 3, or 5 wt% to softwood pulp of three different dewatering resistances. It was found that with refining of a softwood pulp and subsequent addition of long fibres with low bonding ability the tensile-tear relationship can be shifted towards higher strength values. The bonding ability of the man-made fibres was evaluated by pull-out tests and the results indicated that, in relation to the fibre strength, regenerated cellulose (lyocell) was most firmly attached to the softwood network while the glass fibres were most loosely attached.

Measurements of process variations and particle morphology are widely employed in the pulp and paper industry. Two techniques with high potential, infrared thermography and microparticle characterisation, are mainly used qualitatively. Quantitative thermography requires knowledge of the emittance, a material property which has not been measured under many process-relevant conditions. Quantitative characterisation of microparticles, e.g. pulp fines and mineral fillers, requires the analysis of a large number of particles, which can be accomplished using flow microscopes. Flow microscopes for pulp analysis have had insufficient spatial resolution to resolve fines and fillers. Additionally, there has been a lack of methods which can differentiate between fines and fillers in a mixed suspension. State-of-the-art instruments for particle image analysis were evaluated and compared to laser diffractometry, a measurement method based on scattering by diffraction. Laser diffractometry was found to be highly sensitive to the complex refractive index of the particles, and especially to its change due to moisture absorption. A high-resolution imaging flow cytometer and a high-resolution fibre analyser were found to be complementary for characterisation of pure fines and fines/filler mixtures, and superior to laser diffractometry. A method for differentiating between fines and fillers in a suspension based on their autofluorescence and side-scattering was proposed and qualitatively evaluated. Furthermore, a method for measuring the directional and integrated emittance of paper was developed and its accuracy was determined. Measurements on a wide range of samples showed that the emittance of fibre-based materials vary significantly with wavelength, pulp type, observation angle, and moisture content. By applying measured quantitative values of the emittance, the thermal energy emitted by sack paper samples during mechanical deformation could be quantitatively calculated. The increase in thermal energy at the time of rupture was found to correlate well with the elastic share of the mechanical energy that was stored in the sample during its elongation. In summary, the results of this work have facilitated the use of quantitative microparticle analysis and infrared thermography for pulp and paper applications. / Mätningar av processvariationer och partiklars form och storlek utförs i stor skala inom massa- och pappersindustrin. Två mättekniker med stor potential, infraröd termografi och mikropartikel-karaktärisering, används mest kvalitativt idag. Kvantitativ termografi kräver att provets emittans är känd. Emittansen är en materialegenskap som inte har mätts för många förhållanden som är relevanta inom papperstillverkning. Kvantitativ karaktärisering av partiklar kräver att ett tillräckligt stort antal partiklar analyseras, något som kan göras med flödesmikroskop. Flödesmikroskop för mäldanalys har haft otillräcklig upplösning för att karaktärisera mikrometerstora partiklar, t.ex. fines och fyllmedel. Det har heller inte funnits någon metod som kan särskilja mellan fines och fyllmedel i en blandning. Högupplösta mätinstrument för bildbaserad mikropartikelkaraktärisering utvärderades och jämfördes med en laserdiffraktometer, en mätmetod baserad på ljusspridning genom diffraktion. Laserdiffraktometerns mätresultat påverkades starkt av det brytningsindex som antogs för provet, och hur brytningsindexet ändrades med fukthalt. En högupplöst bildbaserad flödescytometer och en högupplöst fibermätare konstaterades komplettera varandra vid mätningar av mäldens finmaterial. De var även pålitligare än laserdiffraktometern vid mätningar av organiskt finmaterial. En metod för att skilja mellan organiskt och oorganiskt finmaterial i en mäld baserat på deras autofluorescens och ljusspridning presenterades och utvärderades kvalitativt. En metod för att mäta den vinkelberoende och våglängdsintegrerade emittansen hos fiberbaserade material utvecklades och dess mätnoggrannhet utvärderades. Mätningar på ett stort antal prover visade att emittansen varierade betydligt med våglängd, mäldtyp, observationsvinkel, och fukthalt. Genom att använda den uppmätta emittansen kunde den termiska energin som frigjordes av ett säckpappersprov vid brottögonblicket beräknas. Denna energi korrelerade väl med den elastiska energi som lagrades i provet medan det töjdes, fram till tidpunkten för brottet. Sammanfattningsvis har resultaten av detta arbete möjliggjort kvantitativ användning av mikropartikel-karaktärisering och infraröd termografi i massa- och papperstillämpningar. / <p>QC 20160122</p>

This study was conducted with the aim of investigating the trends and determinants of South Africa’s sugar production and exports within the TFTA between 1996 and 2014. The specific objectives of the study were (1) to identify trends in South Africa’s sugar production and exports within the TFTA between 1996 and 2014; (2) to determine the drift rate in South Africa’s sugar exports within the TFTA between 1996 and 2014; (3) to investigate the correlation between South Africa’s sugar production and exports between 1996 and 2014; and (4) to determine the factors that affect production and exports in South Africa’s sugar industry in order to identify the industry’s major challenges and opportunities for sustained performance. The secondary data, obtained from the Economic Analysis and Agricultural Statistics Directorate of the Department of Agriculture, Forestry and Fisheries (DAFF), were used to meet the first three objectives of the study. The primary data, obtained by means of a survey questionnaire and interviews with key stakeholders, were used to meet the fourth objective of the study. A 7-point Likert scale was applied to indicate the degree to which each of the determining factors are perceived to affect the performance and resulting competitiveness of the sugar industry. The Johansen test and Porter’s Diamond Model were the analytical techniques used in the study. The results of the analysis of the secondary data revealed continued fluctuations in sugar production in South Africa between 1996 and 2014. On the basis of this, the researcher rejected the hypothesis that there is no trend in South Africa’s sugar production. It was therefore concluded that seasonal variations accounted for these fluctuations in the sugar industry. As determined using the Johansen test, drift rate variations came to 51%, indicating that there is potential for growth in South Africa’s sugar exports. This was confirmed by the results of the bivariate correlation between production and exports which clearly indicated a positive relationship between the two and prompted the researcher to accept the hypothesis that there is a positive relationship between the production and export of sugar. In determining the factors that influence South Africa’s sugar production and exports, a number of obstacles to competitiveness success were identified. With regard to sugar production, applying Porter’s Diamond model revealed that the major constraints experienced by respondents in the study area were the availability of skilled labour; cost of doing business; level of infrastructure development; cost of infrastructure; water availability; climatic conditions; soil quality; rainfall patterns; availability of financial services; access to credit; crime; and HIV/AIDS. In terms of exports, tariffs were found to be the major constraint along with certain of the abovementioned factors. While the majority of respondents view macroeconomic policy and trade policy as export constraints, South Africa’s labour, B-BBEE and competition policies are seen as neither constraining nor supportive. Product design; packaging; labelling and pricing; as well as the manager’s willingness to export; level of education and training; length of time in the business; experience; and language had a positive effect on competitive success. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

O trabalho foi desenvolvido com o objetivo de caracterizar e estudar formas de tratamento de águas residuárias de indústrias de refino de óleo lubrificante e de recuperação de solventes. A fase preliminar teve por objetivo avaliar a biodegradabilidade do despejo combinado dessas duas indústrias. A segunda foi realizada em instalação piloto composta, basicamente, de uma unidade de arraste com ar/tanque de equalização, tanques de correção de pH e de aeração com tempos de detenção distintos, seguidos de tanques de sedimentação. Foram executados testes para avaliar a remoção de material solúvel em n-hexano do despejo da indústria de refino de óleo lubrificante e do efluente final. A unidade de arraste com ar difuso operando com subpressão de 15 mmhg a saída dos gases, vazão específica de ar de 20 ml/l min. E tempo de detenção de 5 dias foi eficiente na remoção de acetona, piridina, benzeno, tolueno, hexano, metil etil cetona e provavelmente solventes clorados. Não apresentou remoção significativa de álcoois, que foram eficientemente degradados no sistema biológico subsequente. Obteve-se remoções superiores a 90%, em termos de dbo e dqo, no processo biológico com tempos de detenção de 20 e 30 dias, e em torno de 80% para os demais. Os sistemas biológicos responderam bem as cargas transientes de solventes, exceto para o tolueno e o álcool isopropílico. / Traditionally, raw materials from solvent recovery and from reclaimed lubricating oil industries are considered hazardous solid waste. Consequently, the best control technology is incineration. This work was developed in order to characterize and to study ways of treating wastewaters from lubricating oil refinery and solvent recovery industries. The experimental part was divided in two phases. The preliminar step aimed to evaluate the biodegradability of combined wastewater from both industries. The second phase was basically carried out in a pilot plant composed by an air stripping unit/equalization tank, pH correction tanks and bioreactors with different retention times, followed by sedimentation tanks. Other than these assays, tests were performed to evaluate the removal of soluble material in n-hexane of the wastewater of the lubricating oil refinery industry and of the supernatant of the sedimentation tank after the bioreactor of 20 days retention.The buble aeration unit operating with a 15 mmHg suppresion to the gas exit, with a specific air flow of 20 mL/L.min. and with a retention time of 5 days was efficient to remove acetone, pyridine, benzene, toluene, hexane, methyl ethyl ketone and probably chlorinated solvents. There was no significative removal of alcohols, that were efficiently degraded in the subsequent biological system. BOD and COD removal efficiencies were better than 90% in the biological process with retention times of 20 and 30 days, and about 80% for the rest. The responses of biological systems to the transient inputs of solvents were well, except for toluene and isopropilic alcohol. Several physico-chemical processes for soluble material in n-hexane removal were studied. The only one to present effluent concentration under the legal limit was the addition of the sodium xylene-sulphonate base demulsifier to the supernatant of the sedimentation tank the bioreactor of 20 days retention.