Modification of softwood kraft pulp by the addition of either polysulfide (PS) or sodium borohydride (NaBH4) has been shown to increase the pulp yield due to a higher retention of glucomannan.  The pulps with higher yield gave a paper with higher tensile index than reference pulp, especially at lower degrees of refining. The higher yield pulps also showed a greater porosity of the fibre wall, indicating an increase in the swelling potential of the fibres. This can lead to increased fibre flexibility and increased joint strength between the fibres and to the higher handsheet tensile index. However, the swelling increase associated with the higher hemicellulose content could also make dewatering more challenging because of the higher water retention of the pulp. The results of this study show however that the positive influence of the increase in yield (fewer fibres and a more open sheet structure) dominates over the negative influence of the higher hemicellulose content on the dewatering properties, especially at lower refining energy levels. Studies simulating full-scale tissue machine dewatering conditions showed that pulps with a higher yield and a higher hemicellulose content had a higher tensile index at the same dryness. Moreover, the same dryness level was achieved in a shorter dwell-time. A given tensile index was also achieved with less refining energy. Increasing the yield and hemicellulose content by the addition of either an oxidizing or a reducing agent in the softwood kraft pulping process thus has a potential for giving high quality fibres for tissue paper production with less refining energy and lower drying energy costs. / <p>Vid tidpunkten för framläggningen av avhandlingen var följande delarbeten opublicerade: delarbete 2 inskickat.</p><p>At the time of the defence the following papers were unpublished: paper 2 submitted.</p>

Abstract Bleaching is an essential process in chemical pulp production for better pulp brightness and longer life expectancy. However, it causes costs such as chemicals, energy, equipment, and loss of yield. Non-linear reactions and several process variables, with interactions, make large plants complicated to model and optimize. As an expensive process bleaching has been a natural target of optimization, but there is still the need to either improve these methods or consider the optimization problem from a new point of view. The aim of this thesis was to develop production optimization methods for pulp bleaching, so that they are practical, usable on-line, easy to tune, and transferable. According to our assumption, neural networks could provide a practical optimization method by combining analytical knowledge with real data. In this kind of problem, the load sharing concept, recognizing interactions in chemical usage and the serial multi-stage nature of the process can simplify the task. The related work in bleaching optimization was studied as well as multi-stage serial process solving in principle, related optimization methods and especially neural networks in optimization. The data were collected during normal mill operation and modeled using neural networks. Optimization was performed based on visualizing the neural network models. The results showed that backpropagation neural networks are capable of modeling parts of the bleach plant and also the entire bleaching operation to such an extent that they are useful in the optimization. The modeling and the tuning can be performed without a profound knowledge of the system, but the process is slower and less reliable. Moving a trained neural network to another mill is inadvisable. It is more reasonable just to transfer the knowledge of variables and network structure. The important factor in on-line production optimization is the stabilization of the disturbances and a well-controlled operation towards a more economical state. Generally, more than half of the total chemicals should be used in the first bleaching stage D0 and the remaining load should be divided so that the dosage at the D1 is about 30% higher than in the D2 stage.

Abstract Quality and economical requirements have raised evident need and interest in the industry to further develop continuous kraft cooking. A Kappa number, representing the cooking degree, is one of the few quality measures of cooking, and usually the only one measured on-line. Cooking degree is mainly controlled by temperature, chemical charge, and cooking time. Cooking conditions strongly depend on the packing degree of a chip column in the digester. At the same time, the packing of a chip column is affected by the cooking degree of chips. A typical problem is that the conditions and cooking degree in the process are not known. To achieve better control, more information about the cooking process is required. The aim of this thesis has been to more accurately describe the cooking conditions and phenomena in the digester scale. Conventional and Downflow Lo-Solids™ continuous cooking processes, producing both softwood and hardwood pulp, were investigated. Information achieved from measurements, and physical and chemical models describing chip scale phenomena, were utilised. Kappa number modelling was based on the use of an optimised and on-line adapted Gustafson's model. Modelling over grade change situations was accomplished by smoothly adjusting the model parameters as a function of temperature change profiles. Real-time profiles of cooking chemicals, temperature, and lignin and carbohydrates contents of chips within the processes were modelled. These real-time profiles were utilised in the modelling of the chip column's packing degree in the conventional process. Based on the developed models, blow-line Kappa numbers of both processes were predicted. By exploiting the prediction results, a new control strategy for the Kappa number was developed. In the strategy, set points for chemical charge and cooking temperature are iteratively solved by using only the developed prediction models of the blow-line Kappa number. It was shown that the modelled profiles of wood components and cooking chemicals can give new information regarding the continuous cooking processes. The modelling results are feasible in control purposes, and they also can support the operators' work. In the new control strategy, compared to the widely used H-factor based control, chemical concentrations can be more precisely taken into account.

No description available.

Denna uppsats analyserar den rytmiska strukturen i fyra dikter av Edith Södergran, två från hennes första diktsamling och två från hennes sista, postuma samling. Den rytmiska analysen utgår ifrån kognitiv metrisk teori och fokuserar på läsarens mentala upplevelse av rytmiska intryck. Dikterna granskas utifrån både ett mikro- och ett makroperspektiv där de individuella versradernas struktur såväl som den övergripande strofkonstruktionen är central.  Huvudsakliga begrepp i den rytmiska analysen är balans och kraft, tagna från George Lakoff och Mark Johnssons teori om perceptionsmönster. Här uppmärksammas dikternas regelbundenhet när det kommer till alternering av stavelsebetoning, versradens längd och möjligheten att upprätthålla stadig meter, där balans och obalans syftar till närvaron eller avsaknaden av symmetrier och kraft syftar till upplevelsen av rytmens tempo.  Uppsatsen utgår även ifrån rytmiska analysmetoder utvecklade av Reuven Tsur och Richard Cureton. Detta innebär att uppsatsen använder sig av begreppet gestalt, lånat från gestaltpsykologi, samt Curetons tre rytmiska komponenter, kallade meter, gruppering och prolongering. Gestalter syftar här på samlingar av enskilda enheter som uppfattas som helheter. Meter står för upplevelsen av slagkraftig, upprepande rytmik, gruppering för upplevda symmetrier i bl.a. stavelsedistributionen och prolongering för känslan av progression mot ett mål i dikten. Dessa begrepp används i uppsatsen för att tydliggöra dikternas rytmiska struktur i sin helhet, medan kraft och balans används för att beskriva den effekt som strukturerna har på läsaren.  Resultatet av analyserna är att de fyra dikterna använder stark variation och skiftningar mellan olika former och perceptionsmönster. Analysen uppmärksammar också att både de tidiga och de sena Södergrandikterna kan ses som rytmiskt komplexa och mångfacetterade. Analysen visar att Södergran har, både i sina tidigaste publicerade och i sina sista dikter, en vilja att konstant variera och komplicera läsarens upplevelse. De ord som bäst karaktäriserar de fyra dikternas rytmiska intryck är förändring och förnyelse.

Reliable energy storage systems are necessary in modern sustainable societies. Storing energy in a spinning flywheel is an old technology which is further investigated in this project. By examining the reactionary forces and friction loss for bearings in a flywheel system, using both MATLAB and Google Spreadsheets, conclusions about the systems design can be drawn. Out of the reactionary forces acting on the rotor, the gravitational force and the mechanical unbalance force proved to be the significant ones, while the gyroscopic reactionary force was relatively small. According to these calculations, to minimize the friction losses, a disc shaped flywheel should be constructed. In general smaller bearing of a chosen bearing type will cause less friction than a bigger bearing of the same type. The bearings also have to be strong and durable enough to meet the requirements of the application.

This thesis is further based on a literature study, in which I took part, where research on difficulties in understanding Newton's third law was compared. In order to investigate how physics teaching on this subject can be designed with a variation theory perspective, an intervention study inspired by a learning study was conducted. The study's object of learning was to develop the student's ability to describe how action and reaction change the object's motion in everyday situations. To fulfill the purpose of the work, the research questions were: What knowledge and understanding about force and motion did the students show pre- and post-teaching? What do the students need to discern in order to understand the object of learning of the intervention study? What patterns of variation enable the discernment of the learning object's critical aspects? The sample consisted of 41 students in year 6, divided into three classes. The data collection consisted of pre- and post-testing and analysis from three lessons. The critical aspects that emerged in the result were: discern that motion is explained by an imbalance of forces, discern that forces arise in interaction between two objects, discern that one of the objects can be the ground (for example a road), discern equality between the objects, human and "non-living”, in force situations and discern that friction is a type of force. Patterns of variation used were contrast, separation and generalization. The comparison between pre- and post-tests revealed that the students developed their knowledge and understanding of the study’s object of learning.

Description and assessment of technology-related concepts aiming at improving the energy conservation in residential buildings. Explanation of the method and discussion of the whole-year simulation results for SOFC micro-CHP systems and Stirling engines in relation with single-family houses of different thermal insulation standards. Benchmark with conventional energy supply systems. Computation of allowable investment costs / Beschreibung und Beurteilung unter technischen, ökonomischen und ökologischen Gesichtspunkten zweier technologiebasierter Maßnahmen zur Effizienzsteigerung der Energiebereitstellung im Gebäudesektor. Darstellung der verwendeten Methodik und der Simulationsergebnisse am Beispiel von SOFC-Brennstoffzellen-Heizgeräten und Stirling-Motoren in Relation mit Einfamilienhäusern verschiedener Dämmstandards. Vergleich mit herkömmlichen und etablierten Versorgungstechnologien Berechnung von anlegbaren Investitionskosten.

The technique to produce pulp has improved and become more complex throughout the years. The purpose of pulping is to liberate the wood fibers and it can be done in two ways, either by chemically or mechanically separating the fibers. This thesis will focus on the commonly used kraft pulping process for eucalyptus and especially on the impregnation stage and how it affects kappa number and alkali consumption. This is done by studying the alkali charge, impregnation time and temperature for the impregnation stage while maintaining constant cooking parameters. This project has shown that the impregnation temperature affects the alkali consumption more than the impregnation time. A correlation between alkali consumption in the impregnation and the kraft cook was seen. When the consumption is high in the impregnation stage, a lower consumption was observed in the cooking stage. / Tekniken för framställningen av trämassa har utvecklats och blivit mer komplex genom åren. Massaframsställningens syfte är att separera träfibrerna ifrån varandra vilket kan utföras på två sätt, antingen på kemisk eller mekanisk väg. Denna studie kommer att fokusera på den beprövade sulfatkokningen och då i synnerhet hur impregneringssteget påverkar kappa numret och alkali konsumtion. För att uppnå detta studeras basningen för alkalin, impregneringstid och temperatur under impregneringen samtidigt som de övriga parametrarna hålls konstanta. Detta projekt har visat att impregneringstemperaturen påverkar alkali konsumtionen mer än tiden den impregneras. Andra studier som exempelvis Weiping Ban and Lucian A. Lucia 2003 och Joni Lehto &amp; Raimo Alén 2013 har har också påvisat denna relation mellan alkali konsumtion och impregneringstemperaturen. Denna studie har även visat en alkali konsumtionstrend mellan impregneringen och sulfatkoket. När konsumtionen är hög under impregneringen så är den lägre i koket.

The purpose of this bachelor thesis was to investigate how charged groups within the pulp fibre affect the beatability and the strength of the papers. To obtain different levels of charges on the pulp it was carboxymethylated. The different pulp samples were beaten to different degrees to investigate how charges interact with the beating. A PFI-mill was used for the beating because of the relatively homogenous effect on the fibres and the low demand for pulp fibres for each beating. The influence of the amount of charged groups on the surface and bulk swelling, as a result of the beating process, was evaluated.   The fibres were then analysed in a Fibre tester and using a microscope to see what had happened to the fibre structure.  The results showed that the PFI-mill mainly affects the surface of the fibres. The beatability, defined as the swelling obtain for a specific energy input, was greatly increased by the introduction of charges. It was also shown that there is a possibility to replace some of the energy input in the mill with the introduction of charges to obtain the same swelling and strength.   Paper sheets were formed from the different samples and some mechanical properties were analyzed. It was shown that the strength was initially improved by the introduction of charges but the improvement was partially lost during the beating. At the highest rate of beating the difference in strength between the samples had disappeared. This can be explained by the fact that the fibres, from the sample with highest number of charges, were destroyed. Microscopic images showed that the fibre was delaminated and at some sites there were extreme balloon-like swellings / Syftet med detta examensarbete var att undersöka hur laddade grupper hos massafibrer påverkar malbarheten och styrkan hos de papper som tillverkats av dessa fibrer. För att skapa olika laddningsnivåer karboxymetylerades viss del av massan för att introducera laddade grupper, två delar av ursprungsmassan karboxymetylerades och en del användes som referensmassa.  De olika massaproverna maldes i olika nivåer för att undersöka hur laddningarna och malningen interagerade. En PFI-kvarn användes för att mala fibrerna då det endast krävs små mängder fibrer och denna typ av kvarn påverkar fibrerna relativt homogent. Fibrerna analyserades sedan i en Fibre tester och med ett mikroskop för att se vad som hade hänt med fiberstrukturen. Resultaten visade att en PFI-kvarn till största delen påverkar fibrernas yta.  Malbarheten, som definierades som den svällning som åstadkoms vid en viss energiinsats i form av malvarv i kvarnen, ökades markant då ytterligare laddningar fanns närvarande i fibrerna. Det visades också att det går att ersätta en del av malningen med introduktion av laddningar till fibrerna för att uppnå samma svällning och styrka. Pappersark tillverkades därefter av de olika massatyperna och några mekaniska egenskaper testades. Det visades att styrkan ökades initialt av introduktionen av laddningar men denna förbättring minskade vid malningen. Vid den högsta malgraden hade skillnaden mellan de olika massorna försvunnit. Det kan förklaras av att fibrerna, från den massatyp med mest laddningar, hade förstörts. På vissa ställen hade fibern helt delaminerats och extrema ballonglika svällningar fanns.