Silicon quantum dots were synthesised wet-chemically by three different methods based on reduction of silicon tetrachloride with the reduction agents potassium naphthalide, sodium cyclopentadiene and the alkalide of potassium. The purpose of these quantum dots was to deposit them on a substrate in order to use them as down converters on top of photovoltaic solar cells for enhanced solar cell efficiency. One possible method for the formation of down converting layers is to incorporate quantum dots into silica thin films by deposition of quantum dots in an ethanol based silica sol, followed by spin coating. It is believed that when the quantum dots are water dispersible, this will make it easier to bind them to the silica network, and a good dispersion in the film is facilitated. The different hydrophilic functionalisations investigated were pentenoxy capping, oxidised pentenoxy capping, oxidised acrylic acid capping and ethanolamine capping. Challenges were encountered during the synthesis of water dispersible quantum dots, the most important were related to agglomeration and purification of the quantum dots. This was believed to be due to the tendency of hydrophilic surface groups to attract each other, interaction with the polar solvent and similar solubility characteristics of the quantum dots and the byproduct salts.Si quantum dots with hydrophobic octoxy capping were also synthesised. Dispersions of these quantum dots were deposited onto solid substrates followed by solvent evaporation. This was done to see whether it was possible to deposit the synthesised quantum dots by this simple approach, to investigate the fundamentals upon evaporation, the degree of agglomeration and the byproducts present in the quantum dot dispersions. It was found that agglomeration was very pronounced after the solvent had evaporated and that quite large amounts of byproducts were present in the final quantum dot dispersions. The most important reasons to this were believed to be too weak steric repulsive forces between the particles, too fast evaporation of the solvent and an insufficient purification procedure. For the use of Si quantum dots synthesised wet-chemically as down converters in solar cells, improvements of the particles are needed.

This work explores the hydrothermal synthesis of LaFeO3 (LFO) nanorods with a high aspect ratio. Synthesis of rod shaped LFO is a stepping stone to the synthesis of strontium doped LFO (LSF) nanorods with high aspect ratio. These LSF rods can be used to structure and increase the area of dense LSF oxygen permeable membranes, which can be applied in the partial oxidation of methane for the production of synthesis gas. Obtaining a larger surface area can increase the oxygen transport through the membrane when the transport is limited by surface exchange reactions. Increasing the oxygen transport is the objective of the work. LFO was attempted synthesised by a direct and a two-step synthesis. Product morphology and phase composition have been explored by the use of SEM and XRD. In the direct synthesis the effect of potassium hydroxide concentration, molar ratio of iron to lanthanum and synthesis duration were varied to investigate the effect of these parameters. LFO was not produced in the direct synthesis; the products consisted of La(OH)3 and Fe2O3. Since LFO was not obtained, a calculation exploring the temperature where LFO become more stable than La(OH)3 and Fe2O3 was performed. The calculations show that the transition temperature where LFO is thermodynamically favoured is close to the operating synthesis temperature. The small driving force for formation of LFO at a temperature close to the transition temperature is the reason why LFO have not formed in the direct syntheses.The two-step method consists of hydrothermal synthesis of La(OH)3 nanorods, which were covered by iron nitrate solution and attempted converted into LFO by a topochemical reaction. In the study performed, the rod structure is lost when the product is calcined at 400 ºC. LFO is not observed formed at this temperature, and LFO nanorods were therefore not obtained in the two-step synthesis.

Interest in renewable energy resources has increased in recent years, and solar cells are one of the areas that have been subject to intensive research. For solar energy to develop into a competitive alternative to fossil fuels, the ratio between cost and efficiency has to be reduced. One of the reasons for low efficiency is the optical losses due to reflection and poor absorption of the red and infrared segment of the light spectrum. Applying more ideal anti-reflection structures and a back-side diffraction layer to increase the path length of light would certainly constitute steps in the right direction. Diatoms, a type of algae, are one of nature's most efficient light harvesting structures. It is suggested that their nano- and microporous silica shell (frustule) possess optical properties that make them attractive options for increasing the efficiency of solar cells. This project aimed at studying the structural and optical properties of selected diatom species and investigating the potential for efficiency enhancements in solar cells through the incorporation of diatoms. Two different species,emph{Coscinodiscus wailesii} and emph{Coscinodiscus sp.}, were investigated through the use of a scanning electron microscope. They were found to have different structures, with the frustule of emph{Coscinodiscus sp.} as having a more regular pore pattern and a more complex structure consisting of several silica layers. The emph{Coscinodiscus sp.} structure was chosen as the foundation for modelling a diffraction grating in GD-Calc, a Matlab implemented simulation software based on rigorous coupled-wave analysis. The diffraction simulations were carried out both on the grating in air and on the grating incorporated in solar cell-like setups. The simulations demonstrated that the diatom structure diffracted light efficiently to higher orders. It was also shown that the anti-reflection structure provided low levels of reflection for a given set of geometric combinations. The back-side diffraction grating reflected light with efficiencies of 0.9, however, the level of diffraction to higher orders was below 0.1. This study shows that that diatom frustule exhibits interesting diffraction grating properties which should be investigated further, both for solar cell schemes and for other applications.

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Arbeidet med vakuuminnfesting for fjernstyrte undervannsverktøy har pågått siden våren 2011, som et samarbeid mellom LBO og studenter ved NTNU. I prosjektoppgaven ”Konsept for innfesting av fjernstyrte undervannsverktøy på flytende produksjonsinstallasjoner”, Holmgard & Låstad 2011, ble det utviklet et helhetlig konsept for innfesting og tilkomst til skroget på et lasteskip. Løsningen ble en rektangulær ramme med en robotarm for gjennomføring av vedlikeholdsarbeidet. Et vakuumsystem med sugekopper fungerte som innfesting.Denne masteroppgaven undersøker gjennomførbarheten til vakuumsystemet, gjennom videreutvikling og systematisk testing i en testrigg. Hovedfokuset lå i å teste innfestingskapasiteten til sugekopper under varierende forhold. Resultatene viste at innfestingskapasiteten i liten grad påvirkes av vann og moderat ruhet. Sugekoppene kan dermed dimensjoneres utfra oppgitte spesifikasjoner fra leverandørene. Det fremstod også hensiktsmessig å bruke vakuumtank som trykkakkumulator, da den fører til hurtigere innfesting, og lavere trykktap ved lekkasje.I tillegg til å gi svar på noen av spørsmålene LBO hadde, har vi gjennom oppgaven tilrettelagt for videre arbeid med vakuuminnfesting offshore. Testriggen og øvrig testutstyr kan benyttes til videreutvikling, og vi anbefaler LBO å gjennomføre ytterligere tester.

A team of 13 NTNU students have developed and built a car to compete in the Shell Eco-Marathon 2012 competition. This master project is a continuation of the specialization project done in the autumn semester 2011. Production started in February and the car was ready on the start line the 18th of May. Out of 22 competing teams in the battery-electric category, the DNV Fuel Figher 2 came in 5th place. The best result achieved was 163km/kWh which can be calculated into an equivalent of 1581km/liter of gasoline. This report includes the design and production process of all sub systems. In addition project management, system engineering, media and the race itself is described.

Denne bacheloroppgaven undersøker ulike vatteringsmaterialer anvendt i møbler, som videre er kombinert med hverandre på forskjellige måter, for å skape ny innovative og dekorative møbeloverflater. Slike materialkombinasjoner kan anvendes for å utvikle ulike teksturer og former med diverse kjensler og hardheter til møbelkledselen.De forskjellige miljø- og helsepåvirkninger av materialer anvendt i prøvene presenteres kort sammenfattet i samband med andre aspekter som brannsikkerhet, gjenvinnings muligheter, mulige sertifiseringer og fiberegenskaper med mer. Videre utsettes prøvene for tester, der deres kvaliteter, som holdbarhet og vaskbarhet undersøkes. Holdbarheten av prøvene testes av en standard holdbarhetstest på Materialtekniska Laboratoriet ved Linköpings Universitet. Materialers vaskbarhet testes ved å måle og registrere endringer etter hver vask. Med dette, registreres i tillegg de synlige endringene, samt forskjellene som kan kjennes på materialets struktur etter vasken. Varigheten av produksjonstid og prisforskjellene mellom de ulike materialkombinasjonene sammenlignes, i tillegg til vekten.Målet med denne avhandlingen er å utvide kunnskap om vatteringsmaterialer og hvordan deres egenskaper påvirker hverandre, slik at materialegenskaper kan mer bevisst anvendes og tilpasses for de tiltenkte anvendningsområdene og anvenderes ulike individuelle behov. De forskjellige materialegenskaper av prøvene er samlet og presentert i en synoptisk oversiktstabell.De mest fremragende materialprøver som dekker de fleste behov, viste seg å være polyestervadd og dun/fjær blanding. I tillegg til dun/fjær blandingen, er også de andre animaliske fibrene som hestehår og ull, materialer som har den beste naturlige brannmotstanden. Hestehår viste seg å være det materialet med minst negative helse- og miljøskadelige påvirkninger.