A test scheme to test micro-beams from diatom frustule has been developed. The method is capable of testing both complete beams and beams made from the individual layers of the frustule. The biosilica is shown to be a very brittle material with an average fracture stress of 336 +- 73 MPa and a flexural modulus of 5.72 +- 2.9 GPa. A comparison of the mechanical properties of the different layers has been performed and shows that the different structural parts greatly influence the overall mechanical properties. Additionally the mechanical properties of frustules that have undergone different chemical treatments have been investigated. The initial results indicate that the softer chemical treatment yields a stiffer biosilica. The challenges of computational modeling of biosilica has been discussed and initial FEM-modeling shows that the porous structure reduces the stiffness of the overall structure. Further development of a combined experimental and computational test scheme is suggested. In addition an AFM-study and nanoindentation tests were performed on the frustules.

1.1 Strukturen av den integrerte HT-vurderingen Konklusjonen av del én av denne oppgaven var at HT-vurderingen bør inngå som en parallell del av konseptutviklingen, som en integrert del av detaljdesignfasen og som et eget steg i form av to sjekklister. På denne måten vil integreringen av HT-vurderingen skje på en naturlig måte som gir ekstra fokus på HT i konseptutviklingen og som forsikrer at HT.komponenter vil virke godt med resten av produktet gjennom tett samarbeid i detaljutviklingsfasen. To sjekklister virker som kontrollpunkter etter første og andre fase. Resultatet av den første kan vise at HT ikke bør anvendes og utviklingen fortsetter som før. Den andre sjekklisten kontrollerer om de valgene man har gjort i konseptutviklingen er riktige. En generell firefases modell er valgt som mal for integreringen, slik at HT-vurderingen kan kombineres med de fleste andre utviklingsmetodikker. 1.2 Innholdet i HT-vurderingen 1.2.1 Sjekklistene Ved å undersøke primæregenskaper ved produktet og dets komponenter benyttes sjekklister for å vurdere om produktet sammenfaller med de sterke sidene ved HT. Ved å benytte en sjekkliste før konseptutviklingen har man mulighet til å finne et behov for HT tidlig i utviklingen. Sjekklisten etter konseptutviklingen benyttes for å kontrollerer om resultatet av konseptutviklingen ser ut til å gi god utnyttelse av HT. 1.2.2 Morfologisk tabell med fokus på ytelse Komponentene som best egner seg for HT avdekkes i første rekke gjennom bruk av en morfologisk tabell. De komponentene i det vinnende konseptet som krever HT tas med i en ny runde med konseptutvikling for HT-komponenter. 1.2.3 Designmetodikk for HT I konseptutviklingsfasen for HT-komponenter benyttes en designmetodikk for HT som baserer seg på tommelfingerreglene ”Kun bruk materiale der det er nødvendig”, ”Kun bruk additivt der det er nødvendig” og regelen om minimum 45 graders helning for å unngå støttestruktur. 1.2.4 Kriterier for god HT-design Kvaliteten av et utviklet HT-design kontrolleres og forbedres gjennom bruk av et sett med kriterier for som må oppfylles for at designet vil gi god utnyttelse av teknologien. Pliktkriteriene er generelle kriterier som er en fordel i alle tilfeller, og må innfris for å oppnå den beste utnyttelsen av teknologien. Ekstrakriteriene er de kriteriene som gir den økte ytelsen av produktet. Minst ett av disse kriteriene bør innfris for at utviklingen av teknologien skal være god. Pliktkriterier: - Lite materialsvinn/redusert maskinering - Enkel ettermaskinering - Minimal bruk av additiv tilvirkning Ekstrakriterier: - Skreddersøm - Avansert geometri - Lav vekt - Forenkler sammenstilling - Økt styrke

Control of growth and surface morphology of perovskite oxide thin films is essential for future electronic devices based on such materials. Uncommon crystallographic orientations, like (111), are particularly interesting in order to control domain formations, but have been shown to grow in a rough manner, because of their polar surfaces. This work aims to elucidate the growth mode of (111) oriented systems, to enable smooth surface structured films. We have investigated the growth of La_{0.7}Sr_{0.3}MnO_3 (LSMO) thin films by pulsed laser deposition (PLD) on (111)oriented SrTiO_3 (STO), characterized by AFM and x-ray diffraction. Substrate surface preparation has been optimized to yield uniform straight step-and-terrace surface structures, as well as the ability to tune the surface structure by different surface preparations. The film surface structure is observed to duplicate the substrate surface; hence, control of the film surface structure is obtained. A detailed description of the growth mode, from thin films of only a few mono layers to thick films of 70nm is presented. The growth mode is complex showing in principle an unstable growth. For the first 20 mono layers (2nm) a roughening transition from step-flow to layer-by-layer is observed. At higher thicknesses a second transition is seen, where the surface breaks up to a 3D surface structure. The critical thickness of the second transition is delayed by reducing the deposition temperature, as expected for strained surfaces, resulting in epitaxial thin films of step-and-terraces structure at least 70nm thick. The crystallinity of the films has been confirmed by XRD measurements. The transition to 3D growth is shown to initiate at the step-edges, and stabilizes with step-bunched steps. A speculative discussion of step-induced strain, and consequently the surface breakup is presented. Furthermore magnetic measurements by VSM in room temperature are presented. The saturation magnetic moment is measured to be $330 emu/cm^3$ at room temperature, which is 100 emu/cm3 larger than other reported values for LSMO/STO(111). The improved understanding of substrate preparation and growth mode in LSMO/STO(111) is important for further work on oxide interfaces, as we believe these results can be expanded to other (111) systems. The magnetic measurements give a preliminary indication that high quality films are necessary to exploit the full potential of these materials.

The objective of this project has been to develop the front suspension and certain parts of the in-wheel motor of NTNU’s new car for Shell Eco-marathon, as well as assisting other team members. NTNU has participated in the Urban Concept class in the European race every year since 2008, with one world record (2009), twice second place, and one failure (2010). The original PureChoice car (renamed DNV Fuel Fighter during the second year) was powered by hydrogen, but the power source was changed to battery this year as a team decision to avoid the pitfalls and challenges with working with a hydrogen fuel cell. Shell Eco-marathon 2012 moves the competition from the typical, smooth, race track to the city streets of Rotterdam. This requires a complete redesign of the suspension to handle the new type of road, since the previous designs have been completely rigid. By not only upgrading the suspension, but also building a completely new car body, new and better mounting points for the suspension could be made and realize fully damped suspension on all four wheels. The new motor specification also allowed the in-wheel motor to be made both lighter and more compact. This work is part of the collective work of more than ten engineering students at NTNU where I have been working towards an earlier delivery of a thesis than the rest of the team because of starting my thesis during the fall. My main responsibilities were in the beginning only the front suspension, with some shared responsibility of the rear suspension. After sketching and presenting a CAD model of how the new motor wheel could be constructed I also became much more involved with the design of the motor wheel which will be lighter and more compact than the previous inwheel motors. This report is divided into three sections – the first discusses the front suspension, the second discusses the mechanical motor design, and the third is a collection of appendices with technical data. All illustrations are self-made unless stated otherwise.

Primary silicon crystals grown from an Al-Si melt has been investigated by solidifying directionally and under electromagnetic field. The goal of this thesis was to increase the size of the primary Si crystals and to agglomerate the crystals to one part of the melt. If achieved, this could simplify the following acid leaching process that is necessary to collect the crystals from the melt. Seven experiments were conducted in a resistance furnace with directional solidification to investigate the agglomeration and size of the Si crystals. A mono-crystalline Si seed was added to the Al-Si melt in three of these experiments as an attempt to increase the crystal growth. The impact of stirring in the melt before solidification was investigated. Al-Si melt was directionally solidified without the aid of seed in three experiments. The silicon content in the alloy and pulling rate during solidification was varied in these experiments to find the appropriate Si crystal growth conditions. The growth of silicon crystals from a mono-crystalline Si seed without aluminium was performed to investigate the impact aluminium had on the seeded growth. One experiment was conducted in an induction furnace to investigate the influence electromagnetic force has on the agglomeration of primary Si crystals. Agglomeration of Si primary crystals was found not to be successful for either directional solidification or electromagnetic force method, as the crystals were not gathered to one part of the melt. The size of the primary Si crystals was not as large as expected and addition of mono-crystalline Si seed did not improve the crystal size. A single Si crystal was successfully grown from a mono-crystalline Si seed when there was no aluminium in the melt.

Atmospheric icing from supercooled droplets in the atmosphere can have catastrophic consequences for a number of man-made structures in regions with cold climate and at high altitude, resulting in accidents with both socioeconomic losses and loss of human lives. To mitigate the icing problem, active de-icing involving chemical, thermal and mechanical techniques have been developed to remove ice that has already accumulated. These techniques are sub-optimal, however, as they are plagued with problems such as high energy consumption, hazard to the environment, high economic costs, and need for frequent reapplication. This thesis takes a look at an entirely different approach, namely utilizing superhydrophobic surfaces to reduce or eliminate the accumulation and adhesion of ice from the outset. Much of the research in the field of superhydrophobicity has involved surfaces with open-cell structures, e.g. pillar-like surfaces and surfaces with bumps and valleys. It has been reported that surfaces with closed cells have a comparative advantage in that they are better at retaining their hydrophobic properties under pressure. This thesis investigates the wetting properties (which are often closely tied to icephobic properties) of closed-cell structures further, using LAMMPS simulations. The simulations show that wetting on these surfaces satisfies the well-known theories of Wenzel and Cassie-Baxter. However, on the small scale on which the simulations were carried out, the effect of tuning the roughness scale is not as predicted by theory. Furthermore, no comparative advantage against open-cell structures could be demonstrated for the closed-cell surfaces. A physical experiment was also carried out, in which the influence of water condensation on the dynamic behavior of water droplets on a nearly-superhydrophobic black silicon surface was tested. The results confirm a well-known problem: Condensation severely deteriorates the water repellency of hydrophobic surfaces. The literature review and experiments in this thesis shows that superhydrophobic surfaces have a great potential for use in anti-icing applications, demonstrating delayed freezing, reduced ice accumulation, and reduced ice adhesion. Nevertheless, major problems are yet to be solved, including deterioration of icephobicity due to mechanical damage, and reduced icephobicity in humid conditions.

Renewable energy production featuring silicon photovoltaic solar cells are of considerable interest to reduce pollution and related environmental changes. Improvements in efficiency along with reductions in cost are key elements to large scale implementation of this technology. Some suggested and attempted methods of improvements that deserves mentioning are: modifying the energy of incident light to better suit the existing band gap along with reduction in losses by applying surface texturing and nitride coatings. Looking to nature for inspiration reveals diatoms and their frustules having pore structures displaying excellent light harvesting abilities. Thus an implementation of such structural features with regards to solar cell improvements would be highly desirable. This thesis was aimed at performing modifications of diatom frustules surfaces by deposition of oxides known to possess properties of up and down-conversion of light as well as attempting to convert diatom frustules to silicon nitride replicas. Coating frustules with oxides possessing properties of up and down-conversion of light combines light harvesting properties of frustules with spectral modifications of incident light. This offers possibilities of solar cell improvements upon implementation. Nitriding of diatom frustules preserves structural features of the frustules and offers increased mechanical, chemical, thermal and anti-reflecting properties for possible solar cell use. Diatom frustules of the species Coscinodiscus wailesii and Coscinodiscus sp. were utilized in all experimental work during this thesis. An initial temperature exposure experiment was performed at temperatures ranging from 400oC-1200oC with increments of 200oC, to gage thermal response of the frustules. In another set of experiments diatom frustules were subjected to one, two and four dip coatings in one of two different precursor solutions. One solution consisted of erbium and yttrium chloride dissolved in a mixture of ethylene glycol and acetonitrile while the other solution consisted of manganese and zinc chloride dissolved in ethylene glycol and acetonitrile. Post dip coating, frustules were annealed at 800oC in normal atmosphere, decomposing chloride precursors to corresponding oxides. Nitriding of frustules was attempted by simultaneous metallothermic reduction in a purpose built reactor vessel where necessary nitrogen was supplied in the form of ammonia at 650oC and 800oC. Ammonia was generated by thermal decomposition of ammonium chloride mixed with calcium oxide. Post experiments, frustules were characterized by use of scanning electron microscope (SEM) featuring energy dispersive x-ray spectrometer (EDS), fluorescence microscopy, photoluminescence spectroscopy and Raman spectroscopy. Frustules in the temperature exposure experiment were found to display small changes to the pores at 600oC. At 800oC the changes were more severe and the changes were found to increase with increasing temperature until complete destruction of the pores along with visible external changes took place at 1200oC. For the coating experiments, no photoluminescent properties were found to exist for frustules coated once or twice. Frustules coated four times were found to display photoluminescent behavior for both types of coatings. Frustules subjected to four coatings with Zn/Mn solution were found to display more temperature related changes in the pores as compared to frustules coated four times with Y/Er solution. Frustules coated with Zn/Mn solution, were found to be contaminated by elevated levels of tin, possibly influencing both thermal and photoluminescent properties. Frustules subjected to simultaneous metallothermic reduction and nitriding at 650oC were found to suffer low conversion and thus only superficial nitride formation. Frustules nitrided at 800oC were found to display higher conversion to silicon nitride. The formed nitride was determined to be β-silicon nitride by Raman spectroscopy. The frustules were also found to contain elevated levels of reduced silicon, for the frustules nitrided at 800oC, this silicon was found to be a mixture of amorphous and nanocrystalline. The nanocrystalline silicon was found to have a crystalline size of ~2.2 nm.

En løsning for to hoved lager og en bunnplate for NOWITECH 10MW referanse turbinen er foreslått basert på dimensjonering i henhold til ekstremlaster. Ekstremlastene er basert på ekstrapolerte laster under vanlig strøm produksjon for normale og ekstreme turbulens forhold spesifisert i IEC61400-3:2008 - Design requirements for offshore wind turbines [1]. Bunnplaten består av to komponenter med en total vekt på 82.4 tonn, bunnplaten har hittil ingen yaw-løsning for overføring av laster til tårnet. Styrkeanalyser er utført basert med ekstremlastene og den høyeste von Mises spenningen ble funnet til å være 208,3MPa. En konfigurasjon av et kulelager og et dobbelt konisk rullelager ble valgt ut ifra SKF sin produktkalatog. Tilslutt er videre arbeid for bunnplaten diskutert.

AlGaAs nanowires (NWs) with axial GaAs inserts, grown with molecular beam epitaxy will be investigated with micro-photoluminescence spectroscopy, including CW and pulsed excitation at cryogenic and ambient temperatures.

Filament winding is a fabrication method for composite material structures, in which fibres are wound around a rotating mandrel. It is a versatile and dexterous process especially well-suited for creating and optimizing parts with a linear rotational axis. Products like pressure tanks, golf clubs or violin bows are commonly created using this technique. The winding itself is done through software solutions that generate a CNC program for the part in question. There are several such software solutions commercially available, all with different modes of operation and functionalities. However, they are also proprietary and offer little to no access into their inner logic. To optimise a part before production Finite Element Analysis software is often used. The part in question is modelled; material, forces and constraints are applied; and an analysis is run. Currently (June 2012), there are few options available for analysing filament wound products. Modelling a part with accurate filament winding layup generally has to be done manually, in a very time-consuming process. In this thesis, the author has performed a pilot study into the development of filament winding software. Software has been developed, capable of integrating both with a filament winding machine and with Finite Element Analysis software, and operating as a link between the two. The software has functionalities to extract geometrical variables from an Abaqus mandrel model; to write G codes and create a CNC program file; simulate a filament winding process in the Abaqus viewport; and, using a CNC program file, add accurate and corresponding layup to an Abaqus part. The main goal of this thesis, however, has been to create something that will serve as a basis from which others can continue development. The intention being that the software will be open source, so that anyone and everyone using it may change, improve and add on to it.