The aim of the thesis is to produce high grade silicon from off-grade materials like sculls and process slags from Elkem Thamshavn. The methods investigated are dense medium separation, optical separation, flotation and metallurgical separation by remelting. Dense medium separation trials are conducted using magnetite suspended in water and aim to find the suspension density where only one phase will float. Optical separation experiments are done to identify light intensity thresholds between refractories, silicon and slag. The viability of flotation without surface activators and at neutral pH are investigated by measuring the zeta potential of each phase. Remelting experiments are done, building on previous work by the author, with the aim of investigating whether adding CaO or MgO to the slag will increase the settling efficiency. No results were obtained in the DMS experiments, because the viscosity of the suspension increased to infinity before the density of either slag or silicon was reached. The flotation experiments showed that flotation is not viable at neutral pH without surface activators, as the zeta potential of slag and silicon is nearly identical. The optical separation experiments were a success. The product fraction had an average silicon content of 74 wt%, compared to 52 wt% in the original off-grade material, while the waste fraction contained 7.5 wt% silicon. The separation efficiency was best for coarser grains, which is the expected result based on theory. The remelting experiments concluded that adding CaO or MgO to the slag will increase the settling efficiency. This was established both by chemical analysis and by surface area analysis of slag samples from each experiment. MgO seemed to contribute more to the settling efficiency than CaO, but because of the large variance between samples, this is not conclusive. The quality of the produced silicon was unaffected or improved by adding CaO, but additions of MgO increased the magnesium content slightly.

ABSTRACT

The aluminium smelter at Hydro Sunndal has experienced problems with an unexpected increased loss of AlF3 from the electrolyte when using a certain quality of alumina. One hypothesis considered was that the fluoride loss was a direct result of unusually high HF formation when the quality was added to the cryolitic melt. This work has set out to study the HF formation potential of three different industrial alumina qualities. Alumina A was an alumina quality that worked well in the smelter. Alumina B was the alumina quality where the aforementioned drop in AlF3 was observed and alumina C, made by the same producer, controversially did not to exhibit the same loss at smelter. The present work has been divided into two parts: a characterisation section, where the aluminas have been characterised by techniques such as LOI, TGA, DSC and XRD, and an experimental section, where the industrial aluminas were added to a cryolitic melt. The HF formation and the corresponding H2O concentration were measured in-situ using a tunable diode laser during the alumina additions to the cryolitic melt. Through this work it has been found that both primary and secondary alumina A form less HF than alumina B and C. The LOI, TGA and XRD characterisation has shown that alumina B and C contain a substantial amount of gibbsite, whilst the gibbsite level in alumina A is negligible. A clear correlation between the quantity of moisture found through LOI characterisation and HF formation has been found. It has also been shown that all types of moisture found through LOI testing contribute to HF formation; both physisorbed and chemisorbed types, as well as structural hydroxyl. From the present work it cannot be explained why alumina B caused a drop in AlF3 in the electrolyte, whilst alumina C did not. One explanation postulated is that alumina C has better scrubber efficiency than alumina B. Examining this hypothesis has been outside the scope of this master work. If variations in scrubber efficiency for the two aluminas fail to explain the drop in AlF3, the solution may be found in parameters outwit the alumina quality e.g. weather conditions at the time of production or storage conditions at the calciner.

Si-nanowires are being introduced as an attempt to decrease the high recombination rate present in silicon based thin-film solar cells by employing radial pn-junctions instead of conventional planar pn-junctions. Previous publications have also shown an additional increase in the amount of absorbed light when covering a silicon-substrate in silicon nanowires which may result in a further increase in the total efficiency of a thin-film solar cell. Successful growth of Si-nanowires has earlier been performed by Chemical Vapour Deposition (CVD), employing gold (Au) as catalytic material. Au is a very stable catalytic material for nanowire growth but Au-residues are unwanted in solar cell applications, and the current experiment has therefore investigated aluminium (Al) as an alternative catalyst material. However, stable Al-catalysed growth has been proven to be difficult and is assumed to be mainly due to rapid oxidation of Al to Al2O3. Most of the nanowires were short, tapered and consisted of worm-like structures. Several unsuccessful in-situ NH3-based cleaning (CVD) processes were attempted. Tin (Sn) was also attempted as a protective coating for the Al-film in order to protect Al from exposure to air during sample transport, without any luck. As solar cells require both p-doped and n-doped sections in order to form pn-junctions, initial investigations were performed on the effect from the addition of dopant gases (B2H6 and PH3) on nanowire morphology. The addition of B2H6 to the gas flow seemed to have much larger effects than PH3 on the nanowire morphology compared to intrinsic nanowires. Both gases resulted in a continuous reduction in the average nanowire length with increasing dopant⁄SiH4 ratios, ultimately leading to a complete inhibition of nanowire growth. The highest usable dopant⁄SiH4 ratios before complete growth-inhibition were found to ~10^-3 for B2H6 and ~10^-1 for PH3. An undesirable tapering effect was also found when adding B2H6 to the gas-flow, resulting in radial growth of amorphous silicon on the nanowire walls already at the lowest dopant ratio (~10^-5). This may complicate the use of B2H6 as a dopant gas for p-type nanowires. Ignoring the fact that the addition of PH3 to the gas-flow reduces the nanowire growth rate PH3 may be assumed to be a good alternative for n-type doping of nanowires as no further effects on the nanowire morphology is observed. The actual implementation of dopant atoms into the nanowire structure may be determined by measuring the electrical resistivity in the nanowire, and a possible four-contact structure has been designed and partly optimized for this purpose. The contact structure has been designed in three layers where two of them are produced by photolithography while the smallest layer by electron-beam-lithography. Note that the structure has not been finalized because of time limitations. Some optimization of the four nanowire contacts remains as some final lift-off problems appeared, and is assumed to be related to either an incomplete development of the smallest features or an observed resist-bubbling because of high Titanium (Ti) deposition temperature. However, a robust three-point alignment procedure has been investigated and found useful for producing accurate contacts to single nanowires and leads to the conclusion of a promising structure.

Iron nanoparticles occur naturally in the environment, but their exposure increases dramatically due to the field of nanotechnology and –medicine. It is poorly understood how the intracellular cooperative mechanisms of submicron particles and microorganisms function on mammalian immune system. In this study, superparamagnetic iron oxide (SPIO) submicron particles will be used to benefit the research within environmental diseases, addressing the biocompatibility of these particles. The size-dependent effects in the immune system of two carboxyl coated SPIO particles with stated sizes 100 nm and 1 µm will be studied in vitro. It would be interesting to determine whether these particles were able to activate the inflammasome, but still, the precise molecular mechanisms for the activation remain unknown. In order to reveal the biocompatibility of these particles, tests were performed as a function of particle concentration ranging from 0.01 to 100 µg/mL using both whole blood and peripheral blood mononuclear cells (PBMC) isolated from healthy donors. The monocytes were first primed with Lipopolysaccharide from Escherichia coli 0111:B4 strain, followed by stimulation with increasing concentrations of the submicron particles. Flow cytometry on whole blood samples identified up-regulation of CD11b monocytes and granulocytes by the particles. In addition, Terminal Complement Complex analyses proved activation of the complement system. It is possible that the particles have been coated with C3b by the complement and phagocytized by the monocytes through CD11b/CD18 receptor. Cytokine secretion from monocytes and whole blood was measured with sandwich ELISA and Bio-plex. The smaller particles seemed to induce higher inflammatory responses than the larger ones. It was, however, interesting to find that the particles themselves caused secretion of active IL-1β without being primed in advance. The mechanisms of the NLRP3 inflammasome activation might be explained by ROS production due to iron imbalance in the cytoplasm. Toxicity of the particles was seen at 10 µg/mL, suggesting their potentially low biocompatibility above this concentration. However, it is suggested better biocompatibility of the silica coated 1 µm particles than the polysaccharide coated 100 nm particles.

Hovedmålet i masteroppgaven har vært å utforske nye gullkatalyserte reaksjoner og anvendelser av propargylestere og allenestere. Allen 14, ble syntetisert fra propargylbromid over to trinn, ved en kjent prosedyre. Kationiske gullkomplekser har en sterk alkynofil karakter som aktiverer alle typer π-systemer for nukleofilt angrep. Dette gjør allen 14 godt egnet som substrat i gullkatalyserte transformasjoner. E-Dien 22a-b, samt Z-dien 23a-b, ble syntetisert i en stereoselektiv gull(I)katalysert reaksjon. Dette er første gang diener har blitt fremstilt fra 2-substituerte allenestere, og det ble observert en høyere Z-selektivitet enn hva som tidligere har blitt observert for usubstituerte allenestere. Dien 22a og 23a ble isolert i et utbytte på henholdsvis 35% og 33% med et E/Z-forhold på 47:53. For dien 22b og 23b var E/Z-forholdet 52:48, og de ble isolert utbytter på 38% og 28%. Elektrofil addisjon til allen 14, etterfulgt av et 1,2-arylskift, ga aldehyd 25 i et utbytte på 45%. Tre nye forbindelser er blitt fremstilt ved en helt ny metode for gull(I)katalysert jodhydroksylering av allenestere. Vinyljodid 24 og 26 ble dannet i utbytter på henholdsvis 59% og 39%, mens omleiret produkt 27, ble isolert i et utbytte på 20%. Syklopropylforbindelse 28 ble syntetisert i en ny gull(I)katalysert ”tandem”-syklopropaneringsreaksjon, fra propargylester 4, i et utbytte på 34%.Fire nye syklopropylforbindelser 18a-b og 19a-b har blitt syntetisert. Disse er dannet i en sykliseringsreaksjon mellom vinylester 17 og propargylester 1b eller 4. Syklopropylforbindelse 18 og 19 er isolert i utbytter på henholdsvis 52% og 76%. Et kiralt NHC-basert gullkompleks 41 har blitt syntetisert, og testet som gull-ligand i syklopropanerings-reaksjon. Det ble funnet et enantiomert overskudd på 5% for cis-forbindelse 43a, og et enantiomert overskudd på 6% for trans-forbindelse 43b. Dette er første gang en kiral NHC-basert gullkatalysator er blitt testet i en gullkatalysert asymmetrisk syklopropaneringsreaksjon.

Et kiralt triazoliumbasert N-heterosykliskkarben-salt (NHC) 1 har blitt fremstilt fra L-fenylalanin 2 og fenylhydrazinhydroklorid 12 i en synteserute som går over fem trinn, og med et totalutbytte på 10%. NHC-salt 1 er blitt testet som organokatalysator i en sykliseringsreaksjon mellom aldehyd 4 og keton 5. Produktet, butyrolakton 6, ble dannet i et trans/cis-forhold på 59:41, og med et enantiomert overskudd på henholdsvis 10% og 19% for trans- og cis-forbindelse 6a og 6b.NHC-salt 1 ble testet som ligand i en gullkatalysert syklopropaneringsreaksjon. Gullkatalysator 15a og 15b ble syntetisert fra NHC-salt 1 og 16 ved hjelp av Ag2O og AuCl(Me2S) i et utbytte på henholdsvis 82% og 85%. Syklopropaneringsreaksjon mellom alkyn 18 og alken 19 ga syklopropylforbindelse 20 i et trans/cis-forhold på 41:59 for gullkatalysator 15a og 38:62 for gullkatalysator 15b. Gullkatalysator 15a ga et enantiomert overskudd på 8% og 6% for henholdsvis trans- og cis-forbindelse 20a og 20b. Gullkatalysator 15b ga et enantiomert overskudd på 10% og 9% for de samme forbindelsene. Dette er første gang en kiral triazolbasert NHC-gullkatalysator har blitt brukt i asymmetrisk syntese.

Prior to this project, a high throughput assay was developed in order to perform automated RNAi screens with siRNA- libraries targeting potential regulators of the G2 checkpoint. The libraries were covering the human kinases, phosphatases and DNA repair. The aim of this project was to validate the candidate hits from the phosphatome screen as possible G2 checkpoint regulators. To validate the candidate hits, esiRNAs were applied in order to down regulate the target proteins, and G2 checkpoint abrogation was assayed by flow cytometry analysis. To confirm that the assay did work, the effects of inhibiting WEE1 by the small molecule inhibitor, MK1775, were tested in both U2OS and U2OSp53 cells. Both the early and the late G2 checkpoint were tested for.WEE1 was a hit in the kinome screen, and a well-known regulator of the G2 checkpoint. The samples treated with MK1775, and 6Gy were showing a dose-dependent abrogation of the G2 checkpoint when stained for H3-p and analyzed by flow cytometry.In optimization experiments for esiRNA transfection, Effectene was chosen over Oligofectamine as the preferred transfection reagent. The transfection conditions which were decided to be the most efficient in down regulating the target protein were 5μL esiRNA and 10 μL Effectene. For the validation experiments it was focused on the two phosphatases SSH3 and PTPN7. Western blotting analysis showed that the protein level of SSH3 was reduced to less than 50% at two days following transfection with SSH3 esiRNA.The validation experiment did not show any abrogation of the G2 checkpoint by neither SSH3 nor PTPN7 in irradiated cells. More repetitions of the experiment are needed in order to validate- or reject these as false hits. However, the results from a whole-genome DNA damage response siRNA screen were recently published. Neither PTPN7 nor SSH3 were scoring in this screen. These facts are supporting the results that SSH3 and PTPN7 are false hits.

Dette prosjektet ble satt i gang på grunnlag av et ønske om en ny metode for analyse av flyktige forbindelser i marine oljer. En ønsker å se på hvilke flyktige forbindelser som finnes i oljen under normale forhold. Det er da viktig at det ikke dannes degraderingsprodukter som følge av metoden. Ved Short-Path Distillation, SPD, opereres det med lavt trykk, helt ned til 0,001 mbar. Dette gir en lavere fordampningstemperatur slik at flere, og tyngre forbindelser kan destilleres av oljen ved en lavere temperatur. Muligheten for å separere oksidasjonsprodukter fra marine oljer ved SPD og innvirkning av fødehastighet og oppholdstid på mengde forbindelser som destilleres av oljen er studert. Som råstoff ble sildolje produsert ved ulik prosess (termisk behandlet og hydrolysert) benyttet, i tilegg til en fiskeolje bestående av 12 til 15 % sild. I forprosjektet til denne oppgaven ble antioksidanten BHT identifisert i sildoljen produsert ved hydrolyseprosess. Sildoljen var ikke tilsatt antioksidanter. Det er derfor lagt vekt på å studere hvordan denne forbindelsen er havnet i oljen og i hvilken konsentrasjon den er tilstede. Råoljen samt retentat, destillat og kondensat etter separasjon i SPD er analysert ved mengde konjugerte forbindelser, peroksidverdi, anisidinverdi og GC-MS. Ut fra resultatene oppnådd i denne oppgaven kan det konkluderes med at Short-Path Distillation egner seg som metode for å separere de flyktige forbindelsene fra marine oljer. I tilegg til tyngre flyktige forbindelser kan muligens lettere forbindelser fanges ved å utstyre kolonnen med en mer effektiv kuldefelle og/eller en adsorbent før utgangen til vakuumpumpa. For kolonnen brukt i dette forsøket tyder resultatene på at oppholdstiden bør holdes mellom 16 og 22 sekunder. Dette tilsvarer fødehastighet på mellom 7.1 ml/min og 2,8 ml/min. De flyktige forbindelsene som er identifisert er hovedsakelig tyngre flyktige forbindelser (fra 9 til 27 karbon). Pristan utgjør den største toppen på GC-MS kromatogram i sildoljen. Denne forbindelsen samt fytol stammer mest sannsynelig fra degradering av α-tokoferol og karotenoider i fytoplankton og inkorporeres i lipidlaget til sild gjennom næringskjeden.Kilden til BHT i oljen er ikke funnet. Det er imidlertidig avkreftet av BHT kommer fra forhold under selve separasjonen eller enzymblanding tilsatt ved hydrolyse av oljen. Det er beregnet at sildolje produsert ved hydrolyseprosess inneholder minst 0,0017 mM BHT, dette tilsvarer 0,37 mg BHT/L olje. Mengden BHT i oljen er under den lovlige grensen for tilsetning av BHT i animalske oljer og fett.

This project looks at the capillary systems with salt water and oil that can be found in porous stones in oil reservoir. The interactions between the different phases and how salt concentration differences can move the oil. The first problem was to find how the water migrates from one side of an oil droplet to the other due to the concentration difference. This was discussed, but not experimentally verified. The reason for this is the high inaccuracy of the experiments and the lack of knowledge before starting. However, this project gives a lot of important knowledge about the problem, and good suggestions for improvements. It was experimentally confirmed that oil is moving due to the difference in salt concentration. From this, the diffusion coefficient was found and reported to be D = (1.08 ± 0.10) · 10−7 m2/s for glass capillary tubes of radius 0,70 mm and at 60oC, calculated from the phenomenological coefficient L that was found. It was also confirmed that the capillary force does not contribute significantly for this size of the tubes, and therefore L should be independent of the radius. The maybe most interesting result of the experiments and calculations is that the capillary force will contribute significantly to the total force and then also the movement of the oil droplet. This does not happen before the radius of the tubes where under 0,20 mm. The experiments and the estimates agreed well with the radius where the change happens.