This project investigates the propagation of ultra-high energy cosmic raynuclei and protons. A simulation of the propagation subjecting the particlesto energy losses due to cosmological redshift as well as interactions with theextra-galactic background radiation seeks to find the initial conditions at thesource which give the best results on Earth compared to the observations ofthe Pierre Auger Observatory (PAO).The results agree with previous works of the same kind that a chemicalcomposition of medium-weight fits the observed air shower data best. Thestarting conditions which gave the best results for the air shower characteristics<Xmax> and RMS(Xmax) were dN/dE proportional to E^{-alpha} with alpha = 1.6 for an initial chemical composition of 25% nitrogen and 75% silicon. Other combinations of themedium-weight nuclei also yielded similar results.No starting conditions could accommodate both the observed dN/dE and theair shower data simultaneously. Other works indicate that this might beimproved by the implementation of extra-galactic magnetic fields, but it couldalso indicate that the error margins in the observed data are underestimated

In this thesis we study the phase diagram of quantum chromodynamics in an effective low-energy theory at zero baryon chemical potential but finite temperature and isospin density. We investigate pion condensation at finite temperature and isospin chemical potential $mu_I$ in two different approximation schemes of the linear sigma model; the Large-$N$ and Hartree approximations at leading order. While being a simple model, the linear sigma model allows for phase transitions of both the first and second order, as well as crossover transitions at the physical point. The large-$N$ approximation yields results typical for mean-field approaches, including a second order phase transition with critical exponent $nu = frac{1}{2}$. At the physical point we find that pion condensation occurs below a threshold temperature $T_c(mu_I)$ only for $mu_I geq m_pi$. Due to the symmetry of the $O(N)$ expansion, the large-$N$ approximation also obeys Goldstone's theorem, yielding a massless Goldstone mode in the pion condensed phase.By contrast, we find a large violation of Goldstone's theorem in the Hartree approximation, with the Goldstone mode achieving a mass of $200 ~hbox{MeV} approx 1.4~ m_pi$. It is possible that the Hartree approximation's violation of symmetry makes the Goldstone mode tachyonic at low temperatures. However, it appears that the Hartree approximation yields a phase structure much more similar to what has been found in lattice studies, with a first order phase transition at high isospin densities and crossover transitions at lower densities. We have only been able to study the Hartree approximation under the condition that either the chiral condensate or the pion condensate is zero, however, and accurate probing of the phase diagram at the physical point is therefore not possible.

The aim of this thesis is to study the effects of particle precipitation on O3 and OH caused by a moderate geomagnetic storm in late July 2009. The basis is data retrieved over Antarctica from the Odin and Aura satellites for an eleven day period. Vertical profiles were extracted from scans at the limb every 165 Km (Aura) and 500 Km (Odin) covering latitudes on the SH extending to 82 S.Geographical variability of O3 and sparse satellite coverage made it difficult to observe storm effects on a latitudinal/longitudinal scale. Zonal means post-storm show a considerable drop of ozone (30-50 %) below 80 Km, and a distinct increase (50 %) at altitudes above 80 Km.Comparison of the zonal means of O3 and OH reveal high concordance between areas of rising hydroxyl and areas of ozone depletion, suggesting that the increase of OH production during the storm is the main cause of O3 depletion. The extent of the O3 and OH changes occur from geomagnetic latitudes greater than 60 S and extend into the polar regions.The zonal means indicate that the OH causes the initial O3 loss, and then hydroxyl disappears rapidly. The O3 remains depleted for four days descending in the polar vortex suggesting contribution from other species (NOx). Time series binned around geomagnetic latitude 62 S were compared with ground-based microwave observations from the Troll station, Antarctica. The two data sets are consistent, showing ozone losses in the order 30-50 % and a gradual poleward descent of this depletion.

In this thesis the results from simulations of a tandem intermediate band solar cell are presented and discussed. Renewable energy sources have become increasingly important, because of global environmental concerns. To make the solar cell technology more viable as an energy source, the study of how to increase the solar cell efficiency is important. The intermediate band solar cell (IBSC) has been introduced as a cell with potential to enhance the efficiency of the conventional single-junction cell. IBSCs have limiting efficiencies of 63.3%. This limit can be further increased by combining two different IBSCs in a tandem cell or combining an IBSC with a conventional single-junction cell. The principle of detailed balance is used to find the limiting efficiencies for possible band gap combinations. Similar analysis of the intermediate band tandem cell has been done previously for black-body radiation. In this thesis the reference AM1.5 spectra have been used, and concentration levels of 1, 100 and 1000 suns. During the work, a model of the intermediate band solar cell, single-junction cell and the complete tandem cell have been coded in Matlab.The tandem intermediate band solar cell will have six different band gaps and is hence comparable with a six single-junction tandem cell. Tandem cells with combinations of a single-junction cell and an intermediate band solar cell, having in total four different band gaps, have also been simulated.In addition to a higher maximum efficiency, the tandem IBSCs are found to have large ranges of useful band gap energies. Semiconductor materials not considered for the single-junction cell or the single intermediate band cells are viable for making tandem IBSCs.The main results in this thesis conclude that the four terminal tandem IBSC has a maximum efficiency of 54.93% for 1 sun, 62.74% for 100 suns, and 67.23% for 1000 suns. These maximum efficiencies are about 11% higher than that of a single IBSC under the same conditions. The maximum efficiencies for the other tandem cells are all higher than that of a single IBSC, with an increase from 1.50% to 9.05%. A wide range of main band gap combinations for the four terminal tandem cells give high efficiencies, but the range is strongly reduced for the two terminal tandem cell. For variations in the band gaps away from their optimal values, the efficiency is affected mostly by variation of the sub-band gap of the top IBSC.

Vanntrevekst er en av de viktigste grunnene til elektrisk havari i h&#248;yspenningskabler.Vanntr&#230;r begynner &#229; vokse n&#229;r den relative fukten(RH) i kabelisolasjonenoverstiger 70 %RH. Det er derfor viktig &#229; holde en lav fuktigheti kabelisolasjonen s&#229; lenge som mulig. Svelleband har som funksjon &#229; hindreaksiell vanninntrenging, men bruk av svelleband senker &#242;g den radielle &#248;kningenav fukt i kabelisolasjonen. Transport av vann i kabelisolasjonen ogsvellebandet blir styrt av transportegenskapene til materialene.Det ble brukt to polymermaterialer i denne oppgaven; En termoplastiskpolyuretan som blir brukt som kappemateriale og et isolerende svelleband.Polyuretan har blitt karakterisert tidligere, mens karakteriseringen av svellebandethar v&#230;rt ufullstendig.Svellebandet ble derfor karakterisert ved hjelp av et tilpasset m&#229;leoppsett.Beregnet diffusjonskoeffisienten viste en sterk ulinearitet ved 30-40 %RH, somikke er blitt beskrevet tidligere, mens l&#248;seligheten er i overensstemmelse medtidligere resultat.Svellebandet ble delt i to og svellepulverpartiklene ble studert med mikroskop.Det ble tatt bilde av svellepulverpartiklene ved &#248;kende relativ fuktog projisert areal ble m&#229;lt. Den m&#229;lte &#248;kningen i m&#229;lt volum viste ikke enoverensstemmelse med den beregnede endringen i diffusjonskoeffisienten. Metodensom er brukt i mikroskoperingen har store kilder til usikkerhet, somkan minimeres ved &#229; se p&#229; svellepulver i l&#248;s form.En numerisk modell for fuktinntrenging i kabelsystemet ble verifisert vedhjelp av en forenklet eksperimentell modell av det lagdelte isolasjonssystemeti h&#248;yspenningskabler. Ved hjelp av en spesialkonstruert testcelle kan en seom den numeriske modellen stemmer overens med faktisk m&#229;lte data.L&#248;selighet og diffusjonskoeffisientene til svellebandet ble lagt til i den numeriskmodellen og simuleringen ble sammenliknet med m&#229;lte fuktopptaksdata.Modellen viser god overensstemmelse med m&#229;lte data for fuktigheterunder ca 37 %RH, f&#248;r den numeriske modellen viser lavere fukt enn m&#229;lingene.Forskjellen mellom m&#229;lte data og numeriske beregninger er aldri st&#248;rreenn 8 %RH.Numeriske beregninger gjort med data fra m&#229;leoppsett for karakteriseringav transportegenskaper til kabelmaterialer stemmer godt overens medm&#229;lte data for det samme systemet. Dette indikerer en god karakteriseringav konsentrasjonsavhengig fuktopptak i polymeriske kabelmaterialer.

We re-derive an algorithm used to calculate solutions for the edge-colouring and dimer problems for planar graphs. The theoretical background for this includes Pfaffian and then as Grassmann Integrals. We develop a new algorithm which is slightly faster and not restricted to planar graphs, and use this new algorithm to find results for small square, hexagonal and kagome grids. The new algorithm is generalised to a larger class of counting problems.Vi forklarer en algoritme for &#229; finne l&#248;sninger til dimer- of kant-fargeleggingsproblemet for flate grafer. Den teoretiske bakgrunnen for algoritmen inkluderer Pfaffianen og Grassmann integraler. Vi lager en ny algoritme som er litt raskere og fungerer utenom flate grafer, og bruker denne for &#229; finne resultater for firkant, sekskant of kagome gitre. Den nye algoritmen blir generalisert til en sto rre klasse telle problem.

When discussing how instruments work and how performers play them, the matter can be viewed from the standpoint of the musician or the scientist. In an attempt to bridge the gap between what science and musical experience know, acoustical methods are used to analyze trombone performance. The results provide a visual description of musical factors in trombone performance. Glissandi, sustained notes, transients, crescendos and decrescendos are studied through measurements of envelopes, spectra and spectral centroids for 9 players of different experience level. The analysis is done with the use of a Matlab toolbox for Music Information Retrieval (&lt;i&gt;MIRtoolbox&lt;/i&gt;). The results shed light on previous studies on trombone performance, and give insight into the matter from a performance perspective. The discussion is focused on combining acoustic theory with musical expertise in order to better understand the full model of trombone performance. Further on, the effect of auditory feedback deprivation upon trombone performance is investigated. Eight trombonists, out of whom four were experienced professionals, and four amateurs, played musical pieces from notation and from memory. In addition, they performed a pitch-bending exercise (lipping). They did this under two playing conditions: A: With a masking noise of 95 dB on headphones, to completely remove auditory feedback from the instrument, and B: Without masking. Measurements of timing and RMS energy yielded statistically significant effects of auditory feedback deprivation on some amateur players, but not on professionals. The results indicate a correlation between musical experience and dependency on auditory feedback. A reason for this is suggested to be a more developed &#147;inner ear.&#148; It is also found that the effects of auditory feedback deprivation were greater for music performed from notation than music performed from memory. This is in agreement with Finney and Palmer (2003), who found that auditory feedback deprivation affects learning conditions, but not retrieval. Previous studies have concluded with no significant effects of auditory feedback deprivation upon keyboard performance (Gates and Bradshaw, 1974; Banton, 1995; Finney, 1997). In this study, observed tendencies towards disruption of performance in pitch bending exercises are found. Many players also failed to hit the correct resonant mode in the performance from notation, and some played &#145;out of tune.&#146; This suggests that auditory feedback deprivation has a more disturbing effect upon trombone performance than in the case of keyboard performance. A likely explanation for this result is that brass instruments provide the player with the possibility of producing several notes for one position or fingering, thus also the possibility of producing a wrong note. In lip-reed instruments, tuning and timbre are controlled by the player, which also introduces more room for disruption of performance. Slight differences on expressiveness in performance, tempo and dynamics were also observed, extending the findings of Repp (1999), who found small, but statistically significant results of auditory feedback deprivation upon expressive keyboard performance.

This report concerns preliminary studies of fingering and fracturing in gelling materials, with the aim of identifying how the phenomena of fingering transitions into fracturing as the breaking medium gradually becomes more solid-like.

The subject of this thesis is the study of the creation of fault lines in a random lattice, provoked by the successive failure of optimal paths. Using the recently developed Optimal Path Cracked model, we investigate how central characteristics of the successive optimal paths evolve as the lattice breaks down, and how this progression of characteristics depends on the magnitude of disorder imparted on the lattice. We then see how the OPC model, while originally proposed in the context of the shortest path problem, can be generalized to alternate optimal path problems, namely the minimax problem and the widest path problem. It is shown that for a given lattice, the minimax OPC is equal to the the backbone of the shortest OPC. The widest path OPC, although constituting a distinct object on any lattice, is shown to scale with lattice size in the same manner as the minimax OPC and the backbone of the shortest path OPC; with the fundamental process behind it being closely related to the minimax OPC process. Lastly, we explain the connection between the OPC process and a variety of other phenomena which have previously been shown to exhibit similar scaling behavior. We show how the OPC process for the widest path problem can be reduced to the shortest path problem on the dual lattice using the limit of very high disorder, the so-called ultrametric limit, and how an algorithm based on invasion percolation can be used as a quicker method of finding an OPC.

In this master thesis, thin lms of ZnO doped with various cobalt concentra-tions have been grown using Pulsed Laser Deposition (PLD). This growthtechnique is preferred because it is able to grow thin lms from a targetmaterial without changing the elemental ratios from the target. The targetsusing during deposition are sintered pellets of ZnO doped with cobalt, withdoping concentrations of 10, 20 and 30 %.The material was chosen because of its potential for Intermediate BandSolar Cells (IBSC). IBSC is a new concept which aims to create solar cellswhich have higher eciencies than the solar cells available today. From de-tailed balance theory, the concept of intermediate band solar cells shows apotential of a 86 % eciency limit under perfect conditions, which is remark-able compared to the conventional silicon solar cell devices on the markettoday with a eciency limit of 41 %.A series of ZnO thin lms of 10, 20 and 30 % cobalt concentration weredeposited by PLD on a sapphire substrate. These lms were, together with asimilar series containing 1,2 and 5 % cobalt concentration deposited on bothsilicon and sapphire substrates, characterized using Scanning Electron Mi-croscopy (SEM), Energy Dispersive X-ray (EDX) Microanalysis, X-ray Pho-toelectron Spectroscopy (XPS), Hall measurements, X-ray diraction (XRD)and optical transmission spectroscopy.In addition, an attempt to make Schottky diodes of the cobalt dopedZnO thin lms and a p-IB-n junction using GaN:Mg and ZnO:Al as the p-and n- emitter was done. These intermediate band solar cell devices weregoing to be studied by recording dark and illuminated current-voltage (I-V)characteristics.The focus in the study has been to determine which cobalt doping con-centration gives the desired properties for use of ZnO:Co in an intermediateband solar cell device, and to study how a solar cell device with an inter-mediate band material can be realized. The experiments were carried outat NTNU NanoLab, NTNU Department of Physics, NTNU Department ofElectronics and Telecommunications and SINTEF Oslo.Optical transmission spectroscopy and XPS showed that the cobalt inthe ZnO:Co lms were Co2+. This indicates that cobalt is substituting forzink in the ZnO lattice. XRD showed the crystal structure to be c-orientedwith reasonable order. The carrier concentration in the ZnO:Co lms were inthe order of 1018- 1019, decreasing with increasing cobalt concentration. Theresistivity in the samples increased with increasing doping concentration.Investigation of the GaN:Mg wafer showed that it did not have the desiredproperties for device fabrication as it showed n-type conductivity insteadof p-type. The Schottky diodes made of Au-ZnO:Co and Pt-ZnO:Co did not show diode behavior because of surface states in ZnO:Co making ohmiccontacts.