Wide angle X-ray Scattering (WAXS) measurements of the layered synthetic silicatesodium fluorohectorite (NaFh) when exposed to pressurized carbon dioxideare reported. With a custom made sample holder placed on top of a coolingsystem, measurements of the NaFh were taken at diferent conditions for temperatureand pressure. The interlamellar spacing of the clay particles is observedto expand approximately 2:4Å in the 001-direction when the sample is held at -20 degrees Celsius and exposed to 15 bar of CO2 for over 9 days, indicating the intercalation of CO2. The d-spacing after intercalation is indistinguishable from the d-spacing of NaFh in the 1WL hydration state. The rate of intercalation process is reported to be dependent on the temperature and the pressure of CO2, with the decreaseof temperature and the increase of pressure beeing favorable for intercalatingCO2. Through various measurements the possibillity of water as the observedintercalated guest substance has been ruled out. Molecular models based onthe swelling free energy are proposed to explain some of the features observedin the experiment.

At nighttime the strongest source of radiation is the hydroxyl night glow. By measuringthe different lines within a band it is possible to calculate the temperature of the mesosphere more than 85km above ground. In order to do this a spectrometer system hasbeen calibrated and software has been developed. The software include a program tocontrol the spectrometer and automatically take data spectra through the night, and aprogram to process the result and calculate the temperature. Two measurements weredone, the (3,1) and (4,2) bands the night of 31. march 2011 and the (7,4) and (8,5)bands the night of 6. may 2011. Both of them were done at NTNU Trondheim (latitude: 63.4 degrees and longitude: 10.4 degrees). The temperature found was 201.85K+/− 3.55K for the (3,1) band, 205.11K +/− 17.94K for the (4,2) band, 199.63K +/−29.86K for the (7,4) band and 196.37K +/− 8.41K for the (8,5) band. Since the (7,4)and (8,5) bands were measured later than the (3,1) and (4,2) bands, they should becolder. The predicted temperature was also calculated using a program developed atThe British Antarctic Survey that uses the MSIS-E-00 [Picone et al., 2003] model for thebackground atmosphere. The predicted temperatures were 202.3K for the (3,1) band,201.7K for the (4,2) band, 176.5K for the (7,4) band and 176.4K for the (8,5) band. Thepredicted temperature and measured temperature are almost the same for the (3,1) and(4,2) bands while it is about 20-25K lower for the (7,4) and (8,5) bands.

The efficiency of multi crystalline silicon solar cells is around 17% but the theoretical limit is 33,7 %. Impurities and dislocations are the main sources for degradation of the solar cell efficiency, especially the combination. Dislocations are also responsible for plastic deformation of materials. To improve the solar cell efficiency it is important to reduce the dislocation density in the raw material for solar cells. The nucleation and multiplication of dislocations in wafer can be suppressed by doping it with a method called solid solute strengthening. In solar cells, the minority carrier lifetime, internal quantum efficiency and the solar cell efficiency are also affected by germanium despite although it is, electrically inactive in the silicon lattice. In this thesis I have studied how all these factors are affected by germanium with different experimental methods. The main goal is to conclude if germanium could be a cost effective dopant in future solar cell production.

The effects of wettability alterations in a 2D network model of a porous media has been studied. By changing the wetting properties of the reservoir through a developed wettability changing algorithm, previously immobile oil clusters in the network are re-mobilized, leading to significant changes in the steady state flow distribution of the model porous mediaThis caused de-stabilization of percolating and trapped clusters as the wettability was changed from an oil wet to a mixed wet system.A critical transition at a certain wetting angle, depending on the initial saturation and lattice size of the system was found. This indicating a possible phase transition from a percolating flow regime to a more uniform flow distribution through the network model. A link between changes in fractional flow and a percolation transition is also suspected, and using the theoretical framework of percolation theory, critical exponents were estimated.

We use the Shockley-Ramo (SR) theorem to calculate terminal currents in single photon excited APDs. A unified notation for the SR theorem is introduced, and we derive the theorem in those particular ways found useful for displaying its limits of applicability. Furthermore some analytically solvable examples that clarify the implications of the theorem have been studied. Finally, some tests with this method on an APD have been carried out, using an existing Monte Carlo code, and the results are discussed.

This thesis will consider two different theories, and apply variational techniquesto each, in order to investigate their true ground states and the possibility ofsymmetry breaking.A scalar field theory is modified by introducing a variational mass-parameter,which also serves as a regularization. The effective potential is calculated to twoloops, and a variational calculation is done to find the extrema of the potential.Secondly, the model of Wess and Zumino is modified by removing the re-strictions on the particle masses. The vacuum energy is then calculated to twoloops, and a variational calculation is performed with the renormalized massesas parameters, in order to determine the true ground state of the theory.It is discovered that the scalar field theory does not develop any symme-trybreaking groundstates, as was predicted by Coleman and Weinberg. Thenon-renormalization and vanishing vacuum energy of the Wess-Zumino model isverifed to two-loop order. Furthermore, it is discovered that the modified Wess-Zumino model has several groundstates which are more energetically favouredthan the supersymmetric state, in which supersymmetry is strongly broken.This may begin explain, if they exist, why we do not see any supersymmetricpartners in our accelerators.

Abstract:In this thesis we will consider different thermal field theories, and derive an equation of state for deconfined matter.This equation of state will be used in the Tolman-Oppenheimer-Volkoff (TOV)-equations to calculate the mass andradius of quark stars.Firstly, a scalar field with a four-point interaction is studied at finitie temperature, and the validity of the perturba-tive expansion is discussed. The pressure is calculated to fifth order.Secondly, QED and QCD are studied at finite chemical potential and zero temperature, and an equation of state fordegenerate quark matter is derived.Next, general relativity is discussed, and Einstein’s field equations as well as the TOV-equations are derived.These last equations are used to model dense stars with different equations of state, and finally the equation describingdeconfined matter is used to determine the mass-radius relationship for quark stars with different central pressures.The results obtained in this thesis indicate in which range of masses and radii quark stars could be observed, andit is discussed how the models used here could be improved and made more realistic.

Experiments on oil droplets made of silicone oil and sodium-fluorohectorite (Na-Fh) clay particles suspended in castor oil were performed. The electric field (E-field)-induced structuring of clay particles placed inside the droplet was studied using two optical microscopes with optical paths normal to one another. This configuration allowed for simultaneous observation of the droplet behavior from both a front view (optical path perpendicular to E-field lines) and a side view (optical path parallel to E-field lines). Prior to the application of the electric field, the Na-Fh particles were randomly dispersed inside and on the surface of the silicone oil droplet. The isotropic distribution in zero field was confirmed by adjusting the focus on the microscope and examining the intersection between the clay particles and focus plane. The application of direct current (DC) electric fields initiated clay particle movement inside the drop and the formation of a ribbon pattern consisting of short particle chains oriented parallel to the E-field direction. The ribbon formation rate displayed a linear E-field dependence and viscous flow inside the droplet seemed to govern the particle structuring. The viscous flow inside the drop was briefly studied together with the phenomenon of droplet rotation appearing at strong DC E-fields. The clay particles behaved differently when an alternating current (AC) E-field was applied. AC E-fields (with frequency equal to 200 Hz) produced chain patterns throughout the drop and parallel to the E-field direction. In both the AC and DC E-field, the particle alignment was time-dependent, and after the application of the E-fields, clay particles slowly spread out and clustered in the bottom of the drop. Settling experiments were also performed and revealed that the stress exerted by the surrounding castor oil on the settling silicone oil droplet was reduced by a factor approximately equal to 1.8 when 1 % Na-Fh clay particles were added. The stability and length of oil-water droplets with smectite clay particles formed in an oval microfuidic T-junction and by using the cross-flow shear method have also been studied. Clay particles were found to affect the length of the formed droplets when the flow rate ratio (dispersed phase flow rate/ continuous flow rate} were larger than 1, but large variations in droplet length and measurement errors make it difficult to conclude whether the effect is systematic or not. The variation in droplet length was generally observed to increase when clay particles were added to the continuous phase (dist. water) and when the flow rate ratio was increased. Surface tension measurements performed with the Du Noüy ring method revealed that the distilled water had some impurities that may have interacted with the clay particles. The pendant drop method was later used to perform surface tension measurement of pure dist. water with or without clays exposed to air or oil. Adding clay particles to the water did not change the surface tension considerably. However, droplet lengths measured at the end of the microfluidic chip showed that clay particles might need more time to affect droplet properties.

3xxx aluminiumslegeringer har Mangan som hovedlegeringselement, og får sin styrke fra plastisk bearbeidelse. 3xxx legeringer har tidligere blitt ansett for å oppnå neglisjerbare endringer i hardhet og styrke som følge av presipitering av dispersoider.Denne masteroppgaven tar for seg hardhetsutvikling ved lave homogeniseringstemperaturer i fire 3xxx Al-Mn-Fe-Si legeringer som følge av presipitering av dispersoider. Legeringene ble homogenisert ved forskjellige temperaturer og holdetider. Utvikling av antallstetthet, gjennomsnittlig ekvivalent diameter og volumfraksjon av dispersoider er koblet til blant annet elektrisk ledningsevne, hardhetsmålinger og strekktesting. Oppgaven belyser teoretiske utregninger av volumfraksjoner, i tillegg til eksperimentelle målinger av disse gjort ved hjelp av transmisjons- elektronmikroskopi (TEM). Scanning elektronmikroskopi (SEM) og NanoSight partikkelanalyse har blitt brukt for å undersøke pulver ekstrahert fra aluminiumsmatrix. Den gjennomsnittlige diameteren av dispersoidene ble sammenlignet med resultater fra TEM-statistikk, disse ble ansett for å være konsistente med hverandre. Identifisering av en konstituent partikkelfase og en silisiumfase ble utført ved hjelp av diffraksjon, disse ble sammenlignet med faser som allerede var kjente legeringen. Det konkludert at økende volumfraksjon av dispersoider førte til en økning i styrke for alle legeringene. En homogen distribusjon av dispersoider i fast løsning, der dispersoidene var relativt små med kort gjennomsnittlig avstand mellom hver partikkel, ga størst effekt.Det ble klart etter flere undersøkelser at en økning av Mn i fast løsning resulterte i en klart minkende elektrisk ledningsevne, samtidig var legeringene med høyt Mn og Si innhold de ledende i presipitering av dispersoider ved økende holdetid.

In this thesis, we examine the antideuteron spectra from annihilations of dark matter in the form of Weakly Interacting Massive Particles (WIMPs). The so-called coalescence model is commonly used to describe the production of antideuterons. This model can be applied directly within a Monte Carlo simulation, but traditionally, approximations have been made that allow coalescence to be applied to the produced nucleon energy spectra after the simulation is done. The traditional approach is based on the assumption that the nucleons produced have isotropically distributed momenta, and is still commonly used today.We find that the assumption of isotropy does not hold; the final state particles from WIMP annihilations are confined in jets, something which increases the antideuteron yield. This effect is missed by the traditional approach, and using the direct implementation of the coalescence model leads to an order of magnitude enhancement of the antideuteron yield. Furthermore, we find that incorrect treatment of input gauge bosons as on-shell particles in Monte Carlo generators lead to underestimates of the antideuteron flux from WIMP annihilations into gauge bosons. This effect is particularly important when using the traditional application of the coalescence model.We also consider the contributions to the antideuteron spectrum from higher order annihilation processes, and find that for the lightest MSSM neutralino as WIMP candidate, these contributions are likely to become important for neutralino masses in the TeV range.