Biomass is an important source of energy and the most important fuel worldwide after coal, oil and natural gas. Biomass does not add carbon dioxide to the atmosphere as it absorbs the same amount of carbon in growing as it releases when consumed as a fuel. Its advantage is that it can be used to generate electricity with the same equipment or power plants that are now burning fossil fuels. However, the low energy density of the biomass requires developments and advances in conversion technologies in order to increase process efficiency and reduce pollution. One of the most promising converting methods for treatment of biomass and waste feedstock is gasification. In this study a highly preheated air/steam of temperatures >800oC is introduced to the gasifier which is fed with wood pellets’ feeding rate 40-50 kg/h. The system is redesigned to work as a continuous type updraft HTAG. The aim of the studies was to test the performance of an Updraft configuration in various operating conditions using Biomass (wood pellets) as the feedstock, and facing primarily technological difficulties and process limitations. Determining the Temperature distribution along the reactor and synthesis gas composition of the process are reported for various operating parameters. During the experiment it is observed that the introduction of more steam flow rate increases the LHV (lower heating value) of the synthesis gases. Three case studies (Case1, Case2, and Case3) are conducted, each case having different biomass feeding rate, steam flow rate and process air flow rate. The result show that the amount of LHV of gas varied from 3 to 4.2 MJ/Nm3, the H2: CO ratio is between 0.5-0.9 and the CO/CO2 ratio has range 1.0-1.7.  Case 3, in which 40 kg/h biomass feeding rate and 80 kg/h Steam flow rate is maintained gives High LHV, high H2/CO ratio and more CO/CO2 ratio among the rest case studies. Further improvement can be done within the reactor, increase in retention time and variation of more parameters can examine, in order to get the optimum result in future.

This report has been written to summarize my work, regarding a will to improve the manufacturing process of a support bracket used for cable ladders. The company concerned in the project have experienced several problems with severe cracking in a flange radius throughout the years of production. The main task has therefore been to identify the problem and to come up with some suggestions of how to avoid these issues ahead.  In order to evaluate the formability of the material used in production, flanging tests have been performed accompanied by finite element analysis in MSC Marc. The conditions of the cut edge subjected to cracking, as well as the cutting tool, have also been investigated by light optical microscopy (LOM), as well as by scanning electron microscopy (SEM).  The results show that the flanging operation in today's production of support brackets extensively exceeds the critical flanging ratio of the steel sheet material. As sheet material tends to adhere to the tool surfaces, issues due to galling can also be stated during manufacturing. In order to improve the production with respect to reliability and a more enhanced product, the company should consider solutions like changing the lubricant or focus on the options of applying a surface treatment on the cutting tool or a brand new tool made from high-quality steel grades, which should be a more sufficient solution in the long-term run. / Denna rapport har skrivits för att sammanfatta mitt arbete med syfte att förbättra tillverkningen av bärok som används till kabelstegar. Det i projektet berörda företaget har under årens lopp upplevt ett flertal problem med svår sprickbildning i en kragad radie. Huvuduppgiften har därför varit att identifiera vad som skulle kunna vara problemet, samt att komma fram till några förslag på hur dessa problem skulle kunna undvikas framöver.   Kragningstest, åtföljda av finita element analyser med hjälp av MSC Marc har utförts för att utvärdera arbetsmaterialets formbarhet. Skicket på den berörda klippkanten, liksom klippverktyget, har också studerats i såväl ljusoptiskt mikroskop (LOM) som svepelektronmikroskop (SEM).   Resultaten visar att kragningsoperationen i dagsläget avsevärt överskrider materialets kritiska kragningsförhållande. Problem med galling kan också fastställas då plåtmaterial tenderar att smeta fast på verktygsytorna under produktionsförloppet. För att förbättra tillverkningen med avseende på tillförlitlighet och en förbättrad produkt, bör företaget överväga lösningar såsom att byta smörjmedel eller att fokusera på en ytbehandling av klippverktyget eller att investera i ett helt nytt verktyg tillverkat av högkvalitativt verktygsstål vilket antagligen skulle vara den mest fördelaktiga lösningen på lång sikt.

New experimental information on the effect of Ni, Cu and Mn on the nitride precipitation temperature and the phase relations in the Fe-Cr-N system is presented. The samples were heat treated under flow of pure and mixed nitrogen gas at different temperatures. The microstructure was investigated by SEM and the nitrogen composition by LECO nitrogen analyzer. The phase equilibria between austenite and Cr2N nitride have been studied at 1173 K and 1373 K using the sealed capsule technique to measure the N activity and SEM-EDS to measure the chemical compositions of the individual phases followed by analysis using LECO nitrogen analyzer. Deviations from theoretical calculations which have been done by Thermo-Calc using the TCFE7 database were observed. E. g. Thermo-Calc predicted single phase austenite at higher Cr content in contrast to experiments which showed austenite and Cr2N nitride phases. Furthermore, the experimental data show slight changes on the extension of the single phase austenite field whereas the calculations show larger effects by addition of Ni, Cu and Mn.

Poly(trimethylene carbonate)–sodium bis(fluorosulfonyl)imide system shows a promising performance as polymer-in-salt electrolytes. The polymer electrolytes with salts concentration from 62% to 71% were tested through DSC, FTIR, EIS and constant current cycling. The solubility of the salts varies in different salts in PTMC. The variation of thermal properties of samples is significant even from the same polymer piece. The measurements show saturation at coordination between Na+ and carbonate groups and ion conductivity at high salt concentrations. Cells with hard carbon and sodium metal electrodes are more stable than cells with Prussian white and sodium metal electrodes during cycling. Cells with 71% salt concentration polymer electrolytes have a good specific capacity and the best stability at 60°C.

No description available.

This project concerns cemented carbides and the carbides that are formed when adding chromium. Cemented carbides are composites, often consisting of tungsten-carbide particles embedded in a cobalt-rich matrix, and are because of their extreme hardness used in for example cutting tools and drills. Chromium is sometimes added when making cemented carbides in order to lower the melting point, reduce grain growth and/or increase corrosion resistance. When adding chromium there is a risk of forming unwanted carbides such as M 23C6, M7C3and M3C2. It is therefore of great interest to know the stability of these carbides. The purpose of this work was to investigate the solubility of Co in M23C6 and M3C2by equilibrium studies. The aim was to produce samples equilibrated in the three-phase regions between liquid‐M23C6‐M7C3 and M3C2‐M7C3‐graphite, to study the solubility of Co in M23C6 and M3C2 respectively. Initial studies were performed at Sandvik Mining and Construction (SMC) to determine the compositions of the samples to be produced and temperatures for the heat treatments. The alloys were heat‐treated at 1450⁰C for three days and were thereafter investigated with LOM and XRD. The work was carried out in collaboration with Sandvik Mining and Construction (SMC). It was difficult to analyze the results with XRD since the intensity peaks in the diffractograms are close or overlapping for the M23C6 and M7C3 carbides. The solubility of Co in M23C6 could not be investigated accurately. The M3C2-M7C3‐graphite sample did not reach equilibrium in the three days of heat treatment. The conclusions that can be drawn from this project are that further work, using longer annealing times, has to be done in order to get more knowledge about the Co solubility in M23C6 and M7C3 carbides.

No description available.

As a part of the independent project in Material Engineering a bachelor thesis was done for thecompany Cogent Surahammars Bruk AB. The purpose of this project is to study productionand lab annealed samples of electric steel to find how magnetic and mechanical properties correlatesto grain size. To achieve this three samples with different compositions were annealedat temperatures within the range of 800 - 950 C. The grains were then analysed with lightmicroscopy, mechanical properties were studied with tensile testing, and lastly magnetic propertiesusing a “single sheet tester”. It was found that titanium has an impact on both mechanicaland magnetic properties. With the uncertainties of the project in mind the most probable causebeing hinderance of grain growth. The yield strength and tensile strength for all samples andtemperatures are within the requirements of the company. The three samples meet the criteriaof permeability and power losses differently. One composition seems to meet the requirements,and the other two exhibit inferior results.

No description available.

Nuclear power technology is currently experiencing a revolutionary development process and its utilization is researched and debated throughout the world whereas sustainability is one of the most important topics in the material science arena. Some components in a nuclear power plant are subject to an irradiating environment which will cause significant damage to the material over time. Thus, it is of utmost importance that the affected materials are well designed for enduring such conditions because of the extensive lifetime of a nuclear power plant. The highly energetic particles that are inherent with nuclear reactions will generate point defects in the microstructure of the material which will alter its macroscopic behavior. Managing heat is crucial in a nuclear power plant and therefore this thesis is devoted to modeling the degradation effect on the lattice thermal conductivity as a result of the point defects, and to establish the intervening relation. This is achieved by ab initio simulations on supercells where the quantum-mechanical forces are calculated with density functional theory and with the generalized gradient approximation for the exchange-correlation term. The phonon Boltz- mann equation is solved by linearization and by using the relaxation-time ap- proximation which allows the lattice thermal conductivity to be calculated for the model. The phonon band modes and the phonon density of states is examined as well. To date there are no reports currently found in the literature where this topicis approached with similar methods. / Kärnkraftsteknologin genomgår just nu en revolutionerande utvecklingspro- cess och dess användning debatteras över hela världen där hållbarhet är en av de viktigaste ståndpunkterna i materialvetenskapsområdet. Vissa komponenter i ett kärnkraftverk blir utsatta för en bestrålande miljö vilket orsakat stor skada på materialet över tid. Det är därför av högsta vikt att dessa material är desig- nade för att motstå sådana miljöer på grund av kärnkraftverkens långa livstid. De högenergetiska partiklarna som är förekommande vid kärnreaktioner gene- rerar punktdefekter i materialets mikrostruktur vilka ändrar de makroskopiska egenskaperna hos materialet. Värmehantering är kritiskt i ett kärnkraftverk och därför är detta arbete de- dikerat till att modellera effekten av försämring av värmeledningsförmågan i kristallgittret, som resultat av punktdefekterna, och att definiera sambandet. Detta uträttas genom ab initio simuleringar av superceller där de kvantmekaniska krafterna beräknas med täthetsfunktionalsteori med en generaliserad approximation av täthetsgradienten för den tillhörande utbytes- och korrela- tionstermen. Boltzmann ekvationen löses med hjälp av linjärisering och med en approximation av relaxationstiden vilket används för att beräkna värmeledningen i gittret för modellen. Fononernas band-moder och tillståndstäthet undersöks därtill. För närvarande finns det inga rapporter bland litteraturen där detta ämne behandlas med samma metoder.