• Angle Dependent Reflectance and Performance of Solar Cells and Absorbers 

      Jordheim, Øystein (Master thesis; Mastergradsoppgave, 2018-05-14)
      In this thesis, the reflectance was measured for angles from 10 deg to 80 deg for different n-type silicon based solar cells and for solar absorbers. The measurements were done with unpolarized, p polarized and s polarized light. The reflectance results show that both the solar cells and solar absorbers perform well under small variation from perpendicular angle well but as the angle of incidence ...
    • Baneberegninger for støv rundt Sola, Vega og Fomalhaut 

      Stamm, Johann Immanuel (Master thesis; Mastergradsoppgave, 2018-05-14)
      Observasjoner av Vega og Fomalhaut tyder på at de har støvbelter rundt seg. Avstanden fra stjerna er rundt 0,2 astronomiske enheter (AE) og størrelsen til støvpartiklene varierer fra noen nanometer til noen mikrometer. Slikt støv fins også i solsystemet. Denne oppgaven handler om å beregne banen til slike støvpartikler etter danning. Det antas at støvet påvirkes av tre krefter: gravitasjon, ...
    • A comparative study of algorithms for blind source separation in the instantaneous linear mixture model 

      Thon, Kevin (Master thesis; Mastergradsoppgave, 2007-06-22)
      This thesis discusses some of the many techniques for performing blind source separation. Its focus is on the theoretical concepts that allow for the problem to be solved. It starts with presenting the EM algorithm, which is the method underpinning many of the algorithms that are presented later in the thesis. Some of the established methods are presented, and we proceed to devolop source separation ...
    • A comparison between optical and SAR classification results for thin sea ice in Storfjorden 

      Quigley, Cornelius (Master thesis; Mastergradsoppgave, 2017-05-31)
      According to the scientific consensus, the Arctic is currently in a state of unprecedented change. In recent years, climate change has been identified as the main cause of Arctic sea ice decline. For this reason, the need to have access to timely and cost effective data is of great importance. Remote sensing via Earth orbiting satellites offers extensive data coverage in areas that are typically ...
    • A detection theoretical approach to digital communications using autoregressive process shift keying 

      Anfinsen, Stian Normann (Master thesis; Mastergradsoppgave, 2001-03-10)
      I klassisk digital kommunikasjon overføres en bitstrøm gjennom en kanal ved å modulere parametrene til en deterministisk bærebølge. Noen kjente eksempler er amplitudemodulasjon (AM), frekvensmodulasjon (FM) og fasemodulasjon (PM). Mottakeren estimerer parametrene til det informasjonsbærende signalet og bruker en deteksjonsregel til å klassifisere den mottatte bølgeformen som en av flere mulige ...
    • Drift wave turbulence and zonal flows 

      Meyer, Ole Hauke Heinz (Master thesis; Mastergradsoppgave, 2012-11-15)
      Anomalously large radial transport levels in fusion devices is commonly believed to be the cause of small-scale edge localized electrostatic drift wave turbulence. We review the basic drift wave instability mechanism and show how poloidally elongated structures can self-consistently emerge from the small-scale turbulent motions through envelope modulation governed by the cubic nonlinear ...
    • Effect of permanent magnets on plasma confinement and ion beam generation in a double layer helicon plasma source 

      Varberg, Erik (Master thesis; Mastergradsoppgave, 2016-06-01)
      The work described in this thesis was carried out to investigate how additional permanent magnets (PM) could affect the confinement and ion beam generation in a plasma which expands from a helicon source. PMs added to a plasma source systems has been shown to provide an increased plasma confinement, but is not widely used. This inexpensive and cheap method of using PMs which does not require any ...
    • Estimation of Neutral Densities in the Thermosphere 

      Stock, Will (Master thesis; Mastergradsoppgave, 2017-05-17)
      Ionospheric energy balance is studied with incoherent scatter radar measurements that allow the estimation of neutral density and temperature from a statistical inversion problem. This method has been successfully studied at low latitudes using data over several years to make a robust model. This has not been done within the high latitude auroral regions and there are many factors that can complicate ...
    • Filament motions in magnetized plasmas 

      Enikeev, Mikhail (Master thesis; Mastergradsoppgave, 2018-02-08)
      Interchange motions of magnetized plasmas due to either a non-uniform magnetic field or a gravitational field lead to charge polarization within a filamentary structure and set up convection. In this project we have provided a clear derivation of the two-field model equations that describe these filament motions. We have also derived an energy theorem for small amplitude oscillations. We have ...
    • Fotoelektriske observasjonar av stjerneokkultasjonar ved måneranda 

      Høydalsvik, Stein (Master thesis; Mastergradsoppgave, 1980-01)
      Analyser av okkultasjonskurvene frå fotoelektriske observasjonar viser at ein stor del av dei observerte stjernene er dobbelstjerner. Okkultasjonsteknikken kan lett åtskilje stjerner som har ein vinkelavstand større enn 0",01 og under gunstige tilhøve kan oppløysinga vere 0",001. I tillegg kan analysen av observasjonen gje vinkeldiameteren til stjerna dersom han er større enn 0",001. Utfrå ...
    • Frequency-dependent magnetizability 

      Anelli, Marco (Master thesis; Mastergradsoppgave, 2010-11-15)
      This work discusses the theory of the magnetizability. The magnetizability is a molecular property defined as the second-order perturbation of the energy in the presence of an external magnetic field. When the magnetic field is static, perturbation and multipole theories lead to an origin-independent expression for the magnetizability, whereas for a frequency-dependent magnetic field its expression ...
    • The harmonizable representation of complex-valued nonstationary random processes 

      Hindberg, Heidi (Master thesis; Mastergradsoppgave, 2005-06-14)
      In this thesis we study the second-order statistical moment functions that characterizes complex-valued harmonizable processes. A real-valued harmonizable process has four Hermitian second-order functions. These functions are equivalent representations of the second-order statistical quantities of the process. For a complex-valued harmonizable process, however, we need the complementary functions ...
    • The impact of Arctic late summer sea ice variability on mid-latitude autumn and winter weather. 

      Stoll, Patrick (Master thesis; Mastergradsoppgave, 2015-11-18)
      The influence of Arctic summer sea ice area on autumn and winter climate in the extra-tropic Northern hemisphere is investigated. During the last decades, the Arctic has warmed more than twice the global average rate, a phenomenon called the Arctic Amplification (AA). AA involves a remarkable decrease of the Arctic sea ice cover and a decrease of the latitudinal temperature gradient. Both are supposed ...
    • Investigation of inflammatory response of macrophages and trophoblasts using structured illumination microscopy 

      Singh, Rajwinder (Master thesis; Mastergradsoppgave, 2017-05-15)
      Approximately 800 women die from pregnancy or childbirth-related pregnancy complications around the world every day. One of the major reasons for these complications is inflammation following infection. Approximately 40% cases of preterm births occur due to microbial invasion in the genitourinary track. During inflammation, macrophages present at the feto-maternal junction release an increased amount ...
    • Investigation of the ion composition in the topside ionosphere at solar maximum using incoherent scatter technique 

      Shulha, Maryna Oleksiivna (Master thesis; Mastergradsoppgave, 2016-05-15)
      The aim of this study was to investigate the altitudinal and diurnal variations of light ion densities in the topside ionosphere during the 23rd and 24th solar maximums. This made it possible to understand the behavior of the ion composition after extended solar minimum and compare how it differs from the preceding solar maximum. The observed variations are compared with estimates of empirical (IRI) ...
    • Investigations of ionospheric disturbances using coherent HF instrumentation 

      Reznychenko, Artem (Master thesis; Mastergradsoppgave, 2016-05-15)
      This work is based on long term monitoring the HF signal data at 9.996 MHz at mid-latitudes from the short radio-path Moscow-Kharkiv and at high-latitudes from the longer radio-path Moscow-Tromso for 2013. The HF signal transmitter is the radio station RWM in Moscow, Russia. The receiver stations are located in Tromso (Norway) and Kharkiv (Ukraine). Using intensity and the Doppler frequency shift ...
    • Kara-Siberian sea ice anomaly and its impact on the atmosphere 

      Balafkan, Nozhan (Master thesis; Mastergradsoppgave, 2018-05-15)
      The behavior of the autumn and winter weather pattern over Europe and Eurasia was investigated during two periods of high and low ice concentration in September over the Kara-Siberian sea. A statistically significant anomalous energy flux from the east Siberian sea to the atmosphere was detected during October of low ice years. Furthermore, an anomalous behavior in the atmospheric circulation was ...
    • Laser diagnostics of the mesospheric magnetic field. Understanding remote laser magnetometry in northern Norway 

      Serrano, Alessandra (Master thesis; Mastergradsoppgave, 2017-05-15)
      This thesis outlines initial motivations and propositions for the Mesospheric Optical Magnetometry (MOM) project, using lidar equipment at ALOMAR observatory in northern Norway to initiate a novel technique for measuring Earth’s magnetic field at approximately 90 km altitude. Included is an in-depth discussion of the physical phenomena within Earth’s mesospheric sodium layer, relevant atomic physics, ...
    • Long-range memory in Earth surface temperatures: spatial scale dependence and land-sea differences 

      Fredriksen, Hege-Beate (Master thesis; Mastergradsoppgave, 2013-05-15)
      The use of long-range memory models as a description of the noise in Earth surface temperatures has increased the recent years, and as a measure of the persistence for such time series we have the Hurst exponent. It is known that sea surface temperatures are more persistent than land temperatures, and that global temperatures are more persistent than local temperatures. We also know that the persistence ...
    • Low-frequency noise power spectrum density characterizing of SiGe HBTs 

      Qi, Peng (Master thesis; Mastergradsoppgave, 2006-06-06)
      The main purposes of this thesis are the Low-Frequency Noise measurement of Silicon-Germanium Heterojunction Bipolar Transistors and its Power Spectrum Density Characterizing. The new generation 375 GHZ SiGe HBTs were measured in this work. We show that most of PSDs of the new generation SiGe HBTs have very ”bumpy” spectra which is contributed by GR noise sources. We investigated their basic ...