Swedish Nuclear Fuel and Waste Management Company, SKB, main mission is to manage and take care of the Swedish nuclear waste. The method chosen is to store the waste far down in the ground in capsules made of copper, which needs to be intact for 100 thousands years. Friction stir welding is used to seal the capsules, which causes oxidation due to heat, but is avoided by using gas protection. If this protection fails, SKB needs to be able to measure the thickness of the oxide to be able to determine if there is too much oxygen in the capsules, which can cause problems in the long run by making the capsules disintegrate and leaking nuclear waste. In this work different methods that SKB can use to measure the thickness of the copperoxide are examined. To find a method for thickness measurements several methods were examined through literature (Spectral-reflectance, Terahertz Time-Domain Spectroscopy, Laser absorption and usage of color). One of these was tested in practice, which was spectral-reflectance. Reference samples were manufactured with known oxide thickness to be used for callibration and teseting of the chosen instrument. The spectral-reflectance measurements were performed on the samples from the work which gave results that agreed with ellipsometry measurements that were made to verify the thickness of the oxides. Since spectral-reflectance worked on the samples and it is a non-contact and non-destructive method, it was the chosen method to be suggested to SKB.

This work investigates the development in microstructure and mechanical properties of roll leveled martensitic high strength structural steel by examinations of roll leveled strip sample and by the employment of roll leveling simulations. The aim of the thesis work is to generate inputs towards finite element method simulations and is performed at a cut to length line utilizing a pre-leveler and a roll leveler at SSAB. Roll leveled strip sample is extracted from a halted roll leveler with 13 roller setup. Mechanical properties are examined on the macroscopic scale by tensile testing and with Instrumented indentation testing on the microscopic scale. Microstructure examinations are conducted with electron backscatter diffraction and roll leveling simulations are performed with a micro bending machine. Tensile testing indicates a noticeable reduction in yield strength from pre-leveled strip portions and a negligible reduction in yield strength from roll leveling on a macroscopic scale in comparison to virgin strip material. Hardness testing in the thickness direction shows decreasing hardness on a microscopic scale. Microstructural examinations reveal a typical texture effect that can be related to hot rolling effect which remains unaffected even after roll leveling. Constant grain size in the top and bottom layers but larger grain size in the mid layer, and a shift in crystallographic orientation on the cross section is revealed by inverse pole figures. Roll leveling simulations with the bending machine on virgin and pre-leveled samples shows the Bauschinger effect as a result of alternating bending tests. Euler angle maps on these bend samples reveal that a large number of grains rotate at a certain degree with the first bend and grains retaining and maintaining their prior orientations with consecutive bends. There is an approximately 1:1 ratio in Euler angle change found for tensile and compression deformation modes. Generation of dislocations during bending simulations is found to differ between tensile and compressive deformation modes. Hardness examination on post bending samples is seen to decrease as a result of the alternating bending process and is discussed to be related to grain relaxation. Several future studies can be possible from the findings of this work which is proposed and discussed as further work. / Detta arbete undersöker utvecklingen i mikrostruktur och mekaniska egenskaper hos rullriktat martensitiskt höghållfast konstruktionsstål genom undersökning av rullriktat bandprov och genom rullriktningsimulering. Syftet med arbetet är att generera input till materialmodeller för finita element-simuleringar och utförs vid formatsträcka 4 hos SSAB i Borlänge. I detta arbete undersöks oriktat, förriktat och riktat band. Ett rullriktat prov extraheras från ett stoppat riktverk med 13 valsar. Mekaniska egenskaper på makronivå undersöks genom dragprovning och på mikronivå med nano-hårdhetsprovning. Mikrostrukturen undersöks med EBSD och rullriktningsimulering utförs med mikrobockningsmaskin. Dragprovning indikerar en märkbar minskning i sträckgräns på förriktade band och försumbar minskning i sträckgränsen på riktade band. Nano-hårdhetsprovning i tvärsnittet visar minskande hårdhet i mikroskopisk skala mellan oriktade, förriktade och riktade band. Mikrostrukturundersökningar avslöjar en varmvalsningseffekt som förblir opåverkad av rullriktningsprocessen och inkluderar en konstant kornstorlek i topp- och bottenlager men större kornstorlek i mellanskiktet samt förskjutning ikristallografisk orientering i bandens tvärsnitt. Rullriktningsimulering med bockningsmaskin på oriktade och förriktade böjprover visar Bauschinger-effekt som ett resultat av alternerande böjning. Euler-vinkelkartor på dessa böjprover avslöjar att en stor andel korn roterar en viss vinkel samt att korn återfår sin ursprungliga vinkel under efterföljande böjningar. Det råder ett nära 1: 1-förhållande i Euler-vinklar för drag- och kompression under bockning medan mängden felorienteringar visar sig skilja sig mellan drag- och kompressionsdeformationslägen. Generering av dislokationer under rullriktningssimulering visar sig skilja mellan drag och kompressionsdeformationslägen. Hårdhet på simuleringsprover ses minska som ett resultat av kontinuerlig bockningsprocess och föreslås uppstå som följd av en avslappningseffekt i korn. Flera framtida studier är möjliga från dessa fynd vilket diskuteras och föreslås som ytterligare arbete.

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There has been a high development of advanced composites with matrix systems of thermoset polymers in the aerostructure industry, but these thermosets can cause problems. Therefore, the aim of this project is to evaluate matrix systems made of thermoplastics, which has been done by theoretical studies. Thermoplastic composites have been developed lately because of a potential reduced costs and weight of the aircraft. Three thermoplastic polymers were chosen to be further investigated, based on process temperature requirements with a range of 200°C, 300°C and 400°C, from Saab Aerostructures.   Thermoplastic composites have a higher price range because of their advanced properties. It is difficult to reduce the price of raw materials and therefore it is considered easier to lower the costs in manufacturing processes. The result of the chosen thermoplastics was that Polyether-ether-ketone (PEEK) is a suitable material in composite matrices within the range of 400°C, because of their unusual high melt temperature and low glass transition temperature. For the temperature range of 300°C, Polyetherimide (PEI) was considered as a suitable polymer because of excellent properties similar to PEEK, but with a lower compressive strength. Polycarbonate (PC) was chosen for the temperature range of 200°C because of advantages like great impact strength and thermal stability.

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Lignin is the most abundant aromatic polymer of natural origin on earth. Currently, it is treated as a waste product of the paper production industry and is burnt as fuel to generate energy. Due to its renewable nature, it represents instead an optimum candidate to substitute non-renewable fossil-based feedstock for the production of plastic products. The present Thesis project deals with the development and characterization of a composite material, made of a lignin-based polymer matrix reinforced with glass fibers. The polymer blend used as matrix, composed of 50% by weight of lignin and 50% of DGEBA, once cured, was found to have a high gel content, corresponding to more than 97%. Moreover, it possesses a significant thermal stability: it starts to degrade at around 250 °C, it loses less than 5% of its weight up to 300 °C (of which 2% is water) and has its maximum degradation rate at 411 °C. Composites made of lignin-DGEBA matrix, reinforced with different contents of short glass fibers, from 10% to 60% of the matrix weight, were prepared. The developed composites showed a considerably decreasing porosity with increasing fiber content, up to the 50% glass fiber composite. In addition, from scanning electron microscopy images, a strong adhesion force between matrix and glass fibers was revealed.Furthermore, tensile tests showed that the produced composites have a good stiffness. In fact, the Young’s modulus varies from slightly more than 4 GPa of the 30% glass fiber composite to almost 5 GPa of the 50% composite, decreasing then in the 60% one. / Lignin är den mest vanliga aromatiska polymeren av naturligt ursprung på jorden. För närvarande behandlas den som en avfallsprodukt från pappersindustrin och används som bränsle för att generera energi. På grund av dess återvinnbarhet är den en optimal kandidat till att ersätta icke förnybar fossilbaserad råvara för produktion av plastmaterial. Det här projektet behandlar utveckling och karakterisering av ett kompositmaterial, med en ligninbaserad polymermatris förstärkt med glasfibrer. Polymeren som används som matris, består av 50 % lignin och 50 % DGEBA. Vid härdning uppvisar den en hög gel halt på mer än 97 %. Dessutom har den en betydande termisk stabilitet: Den börjar bryta ned först vid ca 250 °C, förlorar mindre än 5 % av sin vikt upp till 300 °C (varav 2 % är vatten) och har en maximal nedbrytningshastighet först vid 411 °C. Kompositprover med lignin-DGEBA-matris, förstärkt med olika mängd av korta glasfibrer, från 10 % till 60 % av matrisvikten tillverkades. Kompositerna visade en avsevärt minskande porositet med ökande fiberhalt, upp till 50 % glasfiberarmering. Resultat från SEM bilder visar en stark vidhäftning mellan matris och glasfibrer. Vidare visade dragprov av de framställda kompositerna en hög styvhet. E-modulen varierar från något mer än 4 GPa vid 30 % glasfiberkomposit till nästan 5 GPa av 50 % komposit, men minskar sedan något vid i 60 % inblandning.

Production of bio-oil from biomass is now becoming best substitute of fossil fuels in the transportation sector. Pyrolysis is one of the most promising route to produce bio-oil from biomass.  However, bio-oil needs to be upgraded due to presence of high percentage of oxygenated compounds. Catalytic fast pyrolysis is a very efficient way to produce and upgrade the bio-oil either it is in-situ or Ex-situ arrangement. This study presents the experimental investigation of fast pyrolysis of lignocellulosic biomass by ex-situ catalytic upgradation.  The whole process consists of four parts: biomass grinding and sieving, pyrolysis, ex-situ fixed bed and vapours quenching. The pyrolysis experiment has been performed with nitrogen with or without catalyst to investigate the yield of different products. The analysis of results shows that higher yield of gas is obtained from catalytic upgradation together with the low yield of oil. The more oxygen was removed into CO and CO2 from vapours due to more cracking reactions occurred on catalytic bed. The yield of oil was decreased in catalytic experiments, but it has relatively good energy content due to no water in viscous phase and low acid number. The char yield was same for non-catalytic and catalytic experiments. / Framställning av bioolja från biomassa är ett av de bästa alternativen som kan ersätta fossilabränslen i transportsektorn. Pyrolys är en av de mest lovande teknologierna för att framställabioolja från biomassa. Bioolja behöver dock uppgraderas på grund av en hög andeloxygenerade föreningar. Katalytisk snabbpyrolys är en effektiv metod för att producera ochuppgradera sådan bioolja, antingen genom in-situ eller ex-situ processuppställning. Denna studie presenterar en experimentell undersökning av snabbpyrolys av lignocellulosiskbiomassa kombinerat med ex-situ katalytisk uppgradering. Processen består av fyra delar:förbereda lämplig partikelstorlek av biomassa, pyrolys, ex-situ fastbädd och kondensering avångor. Pyrolysexperiment har genomförts med vätgas med och utan katalysator för attundersöka utbytet av olika pyrolysprodukter. Resultaten visar att en katalytisk uppgraderingger en ökad andel gasprodukt samt ett lågt utbyte av olja. Stor andel syre avlägsnades från oljansom CO och CO2 genom krackningsreaktioner i den katalytiska bädden. Oljeutbytet var lägrevid katalytiska experiment, men visade ett lovande energivärde pga en minskad andel vattensamt ett lägre syratal. Utbytet av kol var detsamma för katalytiska och icke-katalytiskaexperiment.

Ascending trees isn’t completely safe and includes somedangers. Scaling trees with an automated robot wouldminimise the risk of injury. This report describes how ademonstrator was constructed which purpose was to measuredistance while scaling an object. The demonstratorwas limited in its design in the sense that it would onlybe able to climb objects with no obstruction. It was also,due to budget constraints and weight restriction, limited inits power and therefore its ability to scale different objects.The entire demonstrator was initially constructed in a 3Denvironment. Parts of the demonstrator were then cut usinga laser cutter or a water jet cutter. Those parts whichcould not be created by cutting material were made using3D printers. By using an ultrasonic sensor the distance thedemonstrator had moved could be measured. The sensoralso helped with letting the demonstrator know how farup it currently was, allowing it to stop at the appropriateheight set by the operator. As a conclusion both methodsare sufficient for measuring distance but better resultswould be achieved if the demonstrator would be balanced.Using an ultrasonic sensor to measure distance proved towork well for short distances but was unreliable for greaterdistances. The method of counting cycles proved better forgreater distances but it would require higher friction betweenthe grapplers and the scaled surface to be a sufficientmethod. / Att klättra i träd kan vara farligt. Genom att automatiseraträdklättrandet med hjälp av en robot så kan man minimerarisken för skador. Den här rapporten beskriver hurman kan konstruera en prototyp som kan genomföra detta,samt mäta avståndet medan den genomför uppgiften.Prototypen tvingades bli begränsad i sin design på så visatt den endast kan klättra upp för träd som inte har någrahinder på vägen. Prototypen blev också, på grund av begränsningar i budgeten och dess vikt, begränsad i sin styrkaoch blev därför begränsad i dess möjlighet att klättraupp för andra objekt. Hela prototypen designades först ien 3D-miljö. Delar av prototypen skars ut med hjälp aven laserskärare eller en vattenskärare. De delar som intekunde skäras ut gjordes med hjälp av en 3D-printer. Genomatt använda en ultraljudssensor gick det att mäta avståndet som prototypen hade rört sig. Sensorn bidrog också till att prototypen kunde veta hur högt den rört sig, vilketmöjliggjorde för prototypen att stanna när den nått rätthöjd, som förbestämts av operatören. Slutsatsen som gjordesvar att båda metoderna är lämpliga, men resultatenhade varit bättre om modellen varit balanserad. Ultraljudssensornlämpade sig bättre för korta avståndsmätningar dåden inte visade sig vara tillförlitlig för längre avstånd, medandet för längre avstånd visade det sig bättre att användamekanisk mätning, men att den senare kräver bättre friktionmellan grepparmar och klätteryta.

In principle, most of the properties of solids can be determined by their electronic structures. So the understanding of electronic structures is essential. This thesis presents two classes of materials using ab initio method based on density functional theory. One is heavy metal compounds like Ta2AlC, ThO and the other one is hydrogen storage material namely MgH2 surfaces. The study of correlation and relativistic effects in Ta2AlC are presented. Based on our results, Ta2AlC is a weakly correlated system. Our study shows that the spin - orbital coupling does not play a very important role where as the other relativistic corrections such as mass velocity and Darwin terms have a significant effect on the electronic properties. The stability of rock salt like ThO has been proposed based on the first principle calculation. ThO can be stabilized under pressure. The driving force is the sd to f charge transfer in Th. We have investigated the energetics of hydrogen desorption from the MgH2 (110) and (001) surfaces. The doping of foreign metal elements and strain were used to reduce the dehydrogenation energy. The reduction in dehydrogenation energy is caused by the charge localization on the metal atoms which leads to destabilization and the weakening of metal - hydrogen bonds. / <p>QC 20130327</p>

No description available.