A thermal barrier coating (TBC) is used as thermal protection of metallic components exposed to hot gas streams in e.g. gas turbine engines. Due to a high thermal expansion coefficient, low thermal conductivity, chemical- and thermal stability, yttria stabilized zirconia (YSZ) is the most widely used material for TBCs today. In the work presented in this master thesis an aqueous nitrate precursor solution was prepared and deposited on stainless steel substrates by spray pyrolysis to produce 8YSZ coatings (8 mol% of Y2O3 in ZrO2). The precursor solution concentration and deposition parameters, including set-point temperature and volume sprayed, were optimized to produce continuous and crack-free green coatings.The deposited green coatings were characterized by scanning electron microscopy, thermogravimetry and Fourier transform infrared spectroscopy to study the influence of substrate temperature on the microstructure of the green coatings. A substantial change in microstructure was observed for the green coatings in a certain temperature range indicating that a minimum deposition temperature was necessary to obtain crack-free green coatings.Heat treatment was necessary to decompose the nitrate species in the deposited film. During heat treatment, vertical cracks were introduced into the coatings due to the nitrate decomposition. The cracking behavior of the coatings was studied for different drying times and conditions, and it was found that the crack propagation can be controlled to obtain the preferred size and geometry of the cracks. Due to built-up stresses in the coating, which can exceed the fracture toughness of the material, it was found that there was a maximum film thickness achievable before spallation of the coating for a given precursor solution. Therefore, the possibility of spraying multi-layered coatings was investigated. The introduction of a second layer showed that it was possible to double the thickness of the coating.

A study of the effect of various amounts of manganese in solid solution on the recovery and recrystallization behavior of an AlMn-alloy, for different annealing conditions after different degrees of deformation (cold rolling) has been carried out. The alloy studied was a 3xxx-type model alloy with 0.5 wt% Fe, 0.15 wt% Si and 1.0 wt% Mn. The studies were a contribution to the MOREAL-project, where the main objective is to quantify and characterize the softening behavior of recyclable aluminium alloys, with small amounts of manganese, iron and silicon, as a basis to validate and further develop the ALSOFT-model. 5 variants of the AlMn-alloy, with respect to strain and homogenization, were prepared and further investigated.Based on electrical conductivity measurements the different amounts of Mn in solid solution, after the different homogenization (hom.) treatments, were estimated to be approximately 0.85 wt% (as cast), 0.55 wt% (hom. nr. 2) and 0.49 wt% (hom. nr. 3). The reductions of Mn in solid solution by hom. nr. 2 and hom. nr. 3 resulted in less concurrent precipitation and consequently a larger effective driving force for recovery and recrystallization. The high amount of Mn in solid solution for the as cast variants resulted in much concurrent precipitation. Concurrent precipitation was found to delay and suppress the recovery and recrystallization processes. At high annealing temperatures, with no (or little) concurrent precipitation occurring, the recrystallised grain structures were found to be homogeneous, fine grained and consisting of equiaxed grains. In these cases the recrystallised textures were found to be approximately random after a strain of 0.7, while they showed cube textures of weak and medium strength after a strain of 3.0. At low annealing temperatures, with concurrent precipitation occurring, the recrystallised grain structures were found to be inhomogeneous and coarse grained, with grains elongated in the rolling direction. In these cases the recrystallised textures were found to consist of P-textures and ND-rotated cube textures of medium and high strength.A high degree of deformation was found to increase the rate and degree of the recovery and recrystallization processes during the isothermal annealing procedures, and to result in fine recrystallised grain structures, consistent with the increased effective driving force for recovery and recrystallization. A high degree of deformation was also found to increase the rate and magnitude of precipitation during the isothermal annealing procedures.Non-isothermal annealing experiments were carried out to investigate if they could result in significantly different grain structures and textures compared to the isothermal annealing experiments. No significantly different results were achieved, only results directly comparable to the results from the isothermal annealing experiments.

The economical feasibility of commercial, single-junction solar cells is limited by high costs and limited efficiencies. New solar cell concepts and materials are sought to decrease the production costs and increase the efficiency. Intermediate band solar cells (IBSCs) show a promising concept for increased efficiency up to 46.77% as they employ three band gaps that can be matched to the solar spectrum to minimize fundamental losses. Doping of copper gallium disulphide (CuGaS2) with transition metals like Fe and Ni to high concentrations can theoretically form an intermediate band (IB), which for Fe doping gives nearly optimal band gaps for IBSC applications. Copper gallium disulphide is synthesized in an environmentally friendly, inexpensive and simple hydrothermal synthesis which may contribute to decreased costs of solar cell production.The hydrothermal synthesis is developed to produce copper gallium disulphide from copper(I) chloride (CuCl), gallium(III) chloride (GaCl3) and excess thiourea (Tu) (SC(NH2)2) in deionized water. The influence of varying synthesis parameters on product purity, yield and morphology has been investigated through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Energy dispersive X-ray spectroscopy (EDS) is used to investigate doping of copper gallium disulphide and identify particle morphologies formed by different phases. Formation of copper gallium disulphide proceeds through slow decomposition of Tu, driven by an equilibrium shift due to hydrogen disulphide (H2S) evolution and precipitation of sulphides like the intermediate phase digenite (Cu2-δS) into which Ga3+ ions are incorporated. An additional impurity of copper(II) sulphide (CuS) is commonly formed, and gallium(III) hydroxyoxide (GaO(OH)) forms at pH > 0.5. Products of high purity and yield are obtained at 250 °C with concentrations above 0.060 M copper(I) chloride and gallium(III) chloride with the complexing agent 1-pentanethiol, and 0.319 M without 1-pentanethiol. Introducing nickel(II) chloride (NiCl2) or iron(III) chloride (FeCl3) in the hydrothermal synthesis forms vaesite (NiS2) or iron pyrite (FeS2) impurities, respectively, and copper gallium disulphide is not doped to a desirable concentration for IB formation.Color variations in the products reveal off-stoichiometries which contribute to a wide range of particle and crystallite morphologies within each product. Yellow, stoichiometric copper gallium disulphide particles have been deposited on a Si(100) substrate and growth of a red, Ga-rich film was achieved with 1-pentanethiol. These products were subject to photoluminescence spectroscopy (PL) along with off-stoichiometric powders of doped and undoped products, but no luminescence was obtained, possibly due to high defect densities and non-radiative recombination. Dispersions of powders were also subject to absorption spectroscopy which indicate extensive scattering due to wide ranges of particle sizes. The morphology of powder products shows particularly large variations within and between the products. Nanoplate and pyramidal crystallites are produced through nucleation and growth to form network structures and polycrystalline spheres, rods and rose-like particles, which along with the crystallites have varying irregularities and sizes.

There are currently no standard test methods for testing the cathodic disbonding properties of organic coatings at temperatures above 100 C. There are several subsea oil and gas reservoirs with high temperatures, some as high as 200 C. The main goal of this work was the development of a new apparatus and testing procedure for high temperature cathodic disbonding, hereby referred to as HTCD (High Temperature Cathodic Disbonding).A test method for the cathodic disbonding of organic coatings from submerged steel subjected to high temperatures was studied. The test method requires the use of a specialized HTCD apparatus. In this test method, sample plates were mounted between two channels, one containing a hot (150 C) oil flow and the other containing a pressurized, cold, salt (3.5 % NaCl) water flow. Accelerated conditions made it possible to test the cathodic disbonding properties of several coatings in four weeks. Four weeks is a typical duration for coating prequalification tests. Several commercial coating products of different generic types provided by different manufacturers were tested. The results indicate that adequate coating products for high temperature underwater exposure are available.The required cathodic protection current for the samples tested in the HTCD apparatus was continuously monitored. No correlation between the required cathodic protection current and the extent of cathodic disbonding was observed.A long term test with more field like conditions and a duration of 400 days was performed. Low levels of disbonding for most of the tested products in the 400 day test made comparison to the accelerated tests difficult.An attempt was made to determine the oxygen diffusion coefficient of five coating products. The attempt was unsuccessful. The same method had previously been used to study coatings with a thickness of up to 300 micro m, the coatings studied in this work were between 600 micro-metres and 1200 micro-metres. It remains uncertain whether the chosen method can be used for coatings this thick.Results from electrochemical impedance spectroscopy, performed in a pressurized vessel, showed a large reduction in the ionic resistance of a submerged organic coating upon heating from 30 C to 150 C. This showed that elevated temperatures throughout the coating can reduce the ionic resistance to a level where even an intact coating is incapable of protecting the substrate. Studies of coating samples at ambient temperatures after exposure to higher temperatures showed that exposure to heat causes a lasting reduction in impedance. High impedances correlated with good performance in the HTCD tests.Investigation with a scanning electron microscope (SEM) provided images where the extent of the cathodic disbonding was clearly visible. Electron-dispersive X-ray spectroscopy (EDS) enabled the identification of oxides discovered at the holiday and beneath the disbonded coating. Zinc and calcium oxides were identified at and near the holiday; iron oxide was identified beneath the disbonded coating.

Tap hole refractories constitute critical parts of the refractory lining in submerged arc furnaces. For several hours every day, molten slag and metal flow through the tap hole calling for thorough selection of refractory materials able to withstand the intense thermal, corrosive and erosive conditions present in this area. Carbon-based refractories have shown excellent thermal properties and high strength, as well as low wettability towards process materials, and are therefore utilized in silicomanganese production furnaces both as side lining, in the hearth, and in the tap hole area. The aim of this investigation was to determine the compatibility of five refractory materials utilized in the tap hole area of an industrial silicomanganese furnace with two industrial silicomanganese slags: •Investigate the suitability of the selected refractory materials for confining the process materials during industrial production of silicomanganese alloys. •Identify critical refractory wear mechanisms upon slag-refractory interaction at industrial tapping temperatures.Compatibilities were investigated through 12 static crucible tests and two static plate tests in a vertical tube furnace redesigned during this investigation. Slag-refractory interaction was studied after two and four hours holding time at 1367°C ± 1.8°C, 1464°C ± 2.1°C and 1600°C - 0.6°C /+ 0.2°C. Holding temperatures were verified through the wire-bridge method at the melting points of gold and palladium. Visual inspection, as well as optical microscopy and SEM, were utilized to examine the samples after heat treatment.During compatibility experiments, dissolution of refractory matrix due to solubility of oxide refractory binder phases in silicomanganese slags was observed, as well as disintegration of refractory particles due to gas formation at slag-refractory interface, or expansion as a result of phase transformations in refractory material. Direct reduction of manganese oxide from slags and iron oxide present in refractories by carbon and silicon carbide was also observed. Establishment of partial slag-metal equilibriums between iron oxide and silicon metal originally present in slag was observed, as well as formation of silicon carbide at the slag-refractory interfaces. The latter may serve to protect the refractory from wear caused by slags.Based on observations of extensive interaction between silicomanganese slag sample I and ramming paste at 1600°C, the ramming paste investigated cannot be recommended for usage during tap block repair in an industrial silicomanganese furnace. Incipient electrode paste disintegration by slags and silicon carbide tap block – slag interaction were observed after compatibility tests at 1464°C, calling for further investigations of these refractory materials. Tap hole clay and carbon tap block showed minimal signs of interaction with process materials at 1464°C. Refractory porosity seemed to have a larger effect on refractory wear than refractory ash content. Contrary to industrial observations, silicomanganese slag sample I was more corrosive towards the ramming paste and electrode paste investigated than silicomanganese slag sample II.

The aim of this thesis was to create an understanding between the electrochemical performance of a porous Ni-CGO anode used in SOFC, and its microstructural parameters when subjected to redox-cycling. The anode samples were produced consisting of two different layers, and subjected to different number of redox-cycling. Their electrical resistance was measured using electrochemical impedance spectroscopy (EIS), and their parameters were obtained by analyzing cross-section images from the samples obtained by the focused ion beam (FIB) or from simulated 3D-models. A large increase of Ohmic resistance was observed after 3-4 redox-cycles, while there was only a slight increase of the polarization resistance. The high increase of the Ohmic resistance is believed to be due to the observed Ni-coarsening and the net increase of the anode volume due to oxidation of Ni to NiO and subsequently reduced back to Ni. Both the Ni-coarsening and the net volume expansion decrease the Ni connectivity which increases the Ohmic resistance. More electrons are also forced to go through the lower-conducting CGO phase, which increases the Ohmic resistance, though preventing a higher increase since it is connecting the isolated Ni grains together. The low increase of polarization resistance is believed to be due to the large pore-CGO interfacial area, which compensates for the decrease in triple-phase boundaries (TPB). The resolution of synthetic microstructures is not enough to capture constrictivity and tortuosity effects realistically. The dimensions of most of the bottle necks are below 100 nm and hence the size classes must be in the range of 10 nm, which is similar as the resolution of FIB-tomography.

A steady growing global demand for energy and rising greenhouse gas emissions has resulted in several initiatives from the European Union with the purpose of increasing energy efficiency. A part of this strategy is the introduction of energy performance certificates for buildings, containing a numerical primary energy indicator. Another instrument is to encourage an increased use of cogeneration. As a member of the European Economic Area agreement, these events also affect Norway. The main aim of the project was to investigate how various relevant parameters influence the primary energy factor of district heating when a combined heat and power (CHP) plant is the heat producing unit. The study was to be based on Norwegian conditions. To select relevant technologies, a mapping of existing and planned CHP facilities connected to district heating (DH) networks in Norway was carried out. The findings were that at present, there are nine steam cycle CHP plants connected to DH networks that are based on waste incineration, one steam cycle that is based on demolition wood and one reciprocating engine that is running on biogas. The installed electric capacity ranged from 0,3 MW to 22,8 MW and the annual district heating production from 1,5 GWh to 196 GWh. Based on this, it was decided to study steam cycle CHP plants further. Three different sizes were chosen: 2 MWel, 10 MWel and 25 MWel.In addition, the situation in Europe was looked into. Here, steam cycle and combined cycle were found to be the two most dominant CHP technologies. To have a different technology to compare with, a combined cycle with 22,7MWel capacity was also included in the study.By running plant simulations, the effects of part load operation, various district heating supply and return temperatures and different fuel types were quantified. STEAM Pro was utilised to design the steam cycle models, while GT Pro was used to design the combined cycle models. STEAM Pro was also used to perform design simulations for different temperature levels in the DH network and to study the effect of different types of fuels. To be able to investigate the part load performance of the plants based on a given district heating demand, the models from STEAM Pro and GT Pro was imported into Thermoflex and modified.Reducing the DH supply temperature from 120 to 80 °C and the return temperature from 80 to 35 °C in the 10 MW steam cycle plant increased the power efficiency by 25% and the power to heat ratio by 33%, but the total efficiency was only slightly increased. Variation of fuel, on the other hand, influenced the power efficiency and the total efficiency almost equally, and the power to heat ratio was hence left relatively unaltered. The results from the simulations at the defined full load conditions showed that power efficiency was more than twice as high for the combined cycle than for the steam cycle plants, and the power to heat ratio was almost four times higher for the CC plant. The total efficiency was approximately 10 % lower for the combined cycle than for the steam cycles.Performance also varied between the different sizes of steam cycles, and both boiler type and turbine size influenced power efficiencies and power to heat ratios. In contrast, the total efficiencies were close to equal. Part load had a great influence on power efficiency and power to heat ratio for all technology types. Especially at very low load levels, the power efficiency was considerably reduced. The combined cycle experienced a total fall in power efficiency of 40%, while the reduction varied from 60% to only 29% for the steam cycle plants. The part load total efficiency was only slightly reduced for all plants. Based on the part load simulations, annual efficiencies and power to heat ratios were calculated for different annual load distributions. The annual power to heat ratio and power efficiency was clearly influenced by changes in the annual load distribution pattern, while the effect was less notable for the annual total efficiencies. To calculate the primary energy factors, the total efficiency and power to heat ratio results from the CHP plant simulations were implemented in an excel tool developed by [16]. Some other modifications were also performed.The district heating primary energy factors (PEFDH) for the defined base case varied from 0,85 for the Combined Cycle* alternative to 1,4 for the 2 MW steam cycle plant. The base case was defined to have medium energy density(8 MWh/m). This was later found to not represent the actual Norwegian conditions, where the average energy density is closer to 4 MWh/m. When this energy density was used, the PEFDH for the 10 MW steam cycle plant increased 9,4%, from 1,38 to 1,51. This value is still considerably lower than the primary energy factor for the average electricity production in the Nordic countries, which is 2,16.It was found that the combined heat and power plant parameters had a significant influence on the primary energy factors. The power to heat ratio was particularly important when the power bonus method was utilised. One main conclusion is therefore that it is important that the performance indicators that are used for the CHP plant are realistic, and takes into account technology type, part load performance and what load duration curve the plant is subject to. In most of the cases studied, the fuel handling process and the use of additives contributed most to the primary energy losses related to the PEFDH, while the sum of primary energy losses was dominated by the losses occurring in the CHP plant and the fuel handling. Nevertheless, what process and parameters that could potentially improve the PEFDH most depended on technology and choice of allocation method. In all cases studied, pump work related to circulating the DH water and energy consumption related to ash transport, construction and dismantling of the CHP plant and DH pipes were negligible or close to negligible. Heat loss became a considerably more dominant primary energy loss contributor when a low energy density was assumed. In the end, the calculation of primary energy factors involves many choices that influence the results. It is therefore important that the calculation method becomes more standardised. As it is today, some processes are optional, for instance the use of additives. In this study, the use of additives had a non-negligible influence on the results. Furthermore, the CHP simulation results underlined the importance of taking type of CHP technology and operational conditions into account when calculating primary energy factors for this kind of systems.According to NS-EN 15316-4-5, the power bonus method is the allocation method that should be utilised when calculating primary energy factors for district heating. This makes the district heating primary energy factors extremely dependent on power to heat ratio and the choice of PEF for avoided electricity. If the amount of avoided electricity production in fact is smaller than the full amount of CHP production or if the PEF of the avoided electricity is lower than what is assumed, this might lead to a severe underestimation of the PEFDH. The ultimate goal with the use of primary energy is to encourage more efficient energy use. It is therefore important that the issues mentioned in the two paragraphs above are further studied and discussed as a part of exploring how a standard method should be designed to face this challenge.

Tatt for meg flere runder med forsøk og analyser. Tørking av muselever,-hjerte,-lunge,-nyre og -skjelett muskulatur ved +5ºC og -10ºC. Samt lagring ved +4ºC og -20ºC i fem måneder. Resultatene viste en sammenheng mellom lave temperaturer og høye verdier av RIN. De viste også en motsetning til tidligere resultater, med lavere RIN på prøver tørket ved +5ºC, samt uakseptable lave verdier ved lagring i kjøleskap. Dessuten var det en viss forskjell avhengig hvilket organ vi tørket og lagret.

Vannkraftlaboratoriet ønsker å bygge en testrigg for peltonturbiner som tilfredstiller kravene til IEC 60193. Den eksisterende riggen må oppgraderes og det må implementeres mulighet for måling av friksjonsmomentet. I denne oppgaven vil det designes, maskineres og installeres ny lagerbukk med mulighet for friksjonmåling. IEC 60193 gjennomgåes med hovedvekt på laboratorieutrustning og måleusikkerhet for å se hvilke krav som må tilfredstilles. Et komplett hilldiagram kjøres før og etter oppgraderingen og det gjøres usikkerhetsanalyser på resultatene. Videre sammenlignes og analyseres virkningsgradkurvene med og uten friksjonsmoment.Oppgraderingen av Testriggen viser seg å være en suksess. Den gir gode stabile målinger og tilfredstiller IECs krav til usikkerhet. Den står nå klar til å gi nøyaktige målingeresultater for videre forskning på peltonturbiner.

PramPack er en norsk oppstarstbedrift som ble startet av en kvinnelig gründer og to unge studenter i 2007, og som ble solgt til et større selskap i oktober 2010. Denne oppgaven er et case-studie av PramPack og de tre gründerne bak bedriften. Forfatteren av oppgaven var selv én av de tre gründerne. Noen av de viktigste årsakene bak PramPacks suksess presenteres og ses i lys av relevante teoretiske perspektiver: effectuation og bootstrapping. Suksessfaktorene som presenteres er basert på åpne intervjuer med personer som har vært nært tilknyttet bedriften, enten eksternt (eks. produsenter, kunder) eller internt (eks. oppstartsteamet, styret). Oppgaven har som hensikt å gi et detaljert inntrykk av hva det innebærer å starte en bedrift under de samme eller liknende omstendigheter som det PramPack-gründerne var i. De var studenter og hadde begrenset med erfaring, minimalt med penger og ingen kunnskap om den bransjen de skulle inn i. Det er forfatterens ønske og mål at oppgaven skal kunne hjelpe potensielle førstegangsentreprenører til å få et riktigere bilde av hva det å starte en bedrift innebærer.