Institutt for fysikk og teknologi: Nye registreringer
Viser treff 1201-1220 av 1400
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"Numerical modeling of microwave interactions with sea ice"
(Master thesis; Mastergradsoppgave, 2014-06-02)Remote sensing is a key instrument for monitoring sea ice surface properties over large areas. Synthetic Aperture Radar (SAR) as well as Real Aperture Radar (RAR) are two types of radars that are extensively used in this context and measure the backscatter of the surface that they illuminate. Backscattering of waves from rough surfaces is complicated and depends, among other things, on the roughness ... -
Undersjøiske skred i Balsfjorden, Nord-Norge: egenskaper og sammensetning
(Master thesis; Mastergradsoppgave, 2014-06-02)Batymetridata, høyoppløselige seismisk data samt en sedimentkjerne fra indre Balsfjorden, Troms, nord-Norge, har blitt analysert for å undersøke sedimentasjonsprosesser i løpet av Holocen, med spesiell fokus på undersjøiske rasavsetninger. Hovedvekt av denne oppgaven ligger på analyse av den 8,67 m lange sedimentkjernen JM11-001-PC. Dette inkluderte beskrivelse av sedimentoverflate og røntgen ... -
Detection of avalanche debris fields in high resolution SAR imagery
(Master thesis; Mastergradsoppgave, 2014-06-02)During the winter of 2013, Northern Norway saw several large avalanche episodes that caused closed roads and loss of human lives. On Senja and Kval\o ya two large avalanches were reported and images from RADARSAT-2 were ordered in ultrafine mode with the goal of detecting these large avalanches in SAR images. Later that year another two images were ordered from RADARSAT-2 that were be used as reference ... -
Ocean modeling in Northern Norway: A tidal verification study
(Master thesis; Mastergradsoppgave, 2014-06-02)The coast of Northern Norway has for the first time been modeled using an unstructured grid. The modeling is done using two separate grids of different resolution, and the model data is compared to measurements done along the coast to verify its performance for both the fine and coarse grid. The model is a 2-D depth integrated model of tidal circulation with bottom friction. The data have been ... -
Focused fluid flow through the gas-hydrate stability zone on the Vestnesa Ridge, offshore W-svalbard
(Master thesis; Mastergradsoppgave, 2014-07-17)Abstract: Numerous unburied seafloor pockmarks are related to current methane-leakage at Vestnesa Ridge (~79° N), west of Svalbard. About 50 km long and 1-3 km wide, Vestnesa Ridge is a 1-2 km thick sediment drift to the north of the active Molloy transform – on the eastern spreading segment. With its crest at 1200-1300 m depth, the ridge is located on young (<19.6 Ma) oceanic crust. The entire ... -
Polar low trajectories in the Nordic Seas 1999-2013: a statistical analysis using kernel density methods
(Master thesis; Mastergradsoppgave, 2014-06-02)Polar lows are mesoscale cyclones of high intensity, frequently occurring in the Nordic Seas during the winter season. They usually form in baroclinic zones, for instance in regions near ice edges, and they are often maintained by organized convection. Polar lows are characterized by severe weather conditions like heavy snowfall, strong winds, icing and large sea waves. In addition to forecasting ... -
A Simple and Extendable Segmentation Method for Multi-Polarisation SAR Images
(Conference object; Konferansebidrag, 2013)This work presents a simple feature-based multi-channel SAR segmentation method that produces good, smooth, fast and robust results for image segmentation and interpretation. A basic set of six features produce good class distinction for general applications, and the method is easily extendable with new features and for multi-source data fusion. Optional steps of sub-sampling and Markov Random ... -
Optical Trapping, Levitation and Tracking of Microparticles Using Waveguides
(Master thesis; Mastergradsoppgave, 2014-06-02)Microparticles are trapped by optical forces created by the evanescent field present on the surface of an optical waveguide. An optical waveguide loop with an intentional gap is used to propel and stably hold the trapped particles. The particles are trapped in the gap of the loop by counter-diverging fields. Simulations indicate that particles trapped in the gap on a strip waveguide will be levitated. ... -
Simulating and characterizing carbon based solar thermal absorbers
(Master thesis; Mastergradsoppgave, 2014-05-16)The main objective of this project is to determine and characterize the optical and structural properties of carbon nanotube (CNT) coated aluminum substrates to facilitate better understanding regarding their suitability for solar absorption. In this way, it may be possible to utilize this material to produce improved and more efficient spectrally selective solar thermal absorbers in solar thermal ... -
Origin and accumulation mechanism of shallow gas accumulations in the SW Barents Sea
(Master thesis; Mastergradsoppgave, 2014-06-02)Events associated with shallow gas accumulations are reported all over the Norwegian continental shelf. These accumulations are potentially dangerous geo-hazards related to drilling activity, but they can also be of economic interest if the accumulated volumes are large. Petroleum in the Barents Sea has been influenced by the late periods of uplift and erosion creating a complex province. The exact ... -
Time-lapse seismic interpretation of injected CO2 plume at the Sleipner Field, North Sea
(Master thesis; Mastergradsoppgave, 2014-06-02)One of the methods to cope with the increase of emitted greenhouse gases has been to capture CO2 gas from a point source and storing it within the Earths subsurface; “Carbon Capture and Storage” (CCS). Since 1996, Statoil and its partners have injected CO2 into a saline aquifer called the Utsira formation located in the North Sea. About 0.9Mt of CO2 is injected into the formation yearly, with a ... -
Quantifying influence of local air pollution on measurements in Ny-Ålesund and at the Zeppelin station
(Master thesis; Mastergradsoppgave, 2014-06-02)In order to keep the scientific significance of the Ny-Ålesund station on Svalbard as the key place for the monitoring of background air it is needed to assess the influence from local human activities on the air quality. Whether research and tourist activity continues to grow or restrictions to be implied the change of impact may affect air chemistry data quality. Therefore the identification of ... -
Power potential of Rystraumen, Norway
(Master thesis; Mastergradsoppgave, 2014-03-14)The maximum power potential of the tidal current Rystraumen close to Troms , Norway, is assessed both theoretically and from a depth-integrated numerical model (FVCOM). For the theoretical estimate of the maximum power potential, the topography is simplified to the situation in which the channel connects a large basin, unaffected by the energy extraction, to a closed bay. A set of governing equations ... -
On the relation between type-II ion outflow and naturally enhanced ion acoustic lines in the polar ionosphere
(Master thesis; Mastergradsoppgave, 2013-11-15)In this work we investigated the relation between type-II ion outflows and NEIALs. Currently, several ion outflows acceleration mechanisms and NEIALs generation theories have been proposed. In the first part of this thesis we review the most important works regarding these two processes. In the second part we present the results of our analysis, together with some unexpected events which were not ... -
Type-I ion outflow from the high latitude ionosphere
(Master thesis; Mastergradsoppgave, 2013-11-15)The aim of this thesis is to study type-I ion outflows in the high latitude ionosphere. Type-I ion outflows are characterized by strong perpendicular electric fields, enhanced and anisotropic ion temperatures and low electron densities below 300 km, indicating small amounts of hard particle precipitation. We scanned data from the EISCAT Madrigal database over a period of 10 years (January 2000 - ... -
Elemental Abundances in the Fast Solar Wind Emanating from Chromospheric Funnels
(Journal article; Tidsskriftartikkel; Peer reviewed, 2010)We carry out a model study to determine whether a funnel-type flow geometry in the solar wind source region leads to sufficiently fast hydrogen flow to offset heavy element gravitational settling and can thus explain why solar wind abundances are not much smaller than photospheric abundances. We find that high first ionization potential (FIP) elements are more susceptible to gravitational settling ... -
Simultaneous observations of a Mesospheric Inversion Layer and turbulence during the ECOMA-2010 rocket campaign
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)From 19 November to 19 December 2010 the fourth and final ECOMA rocket campaign was conducted at Andøya Rocket Range (69 N, 16 E) in northern Norway. We present and discuss measurement results obtained during the last rocket launch labelled ECOMA09 when simultaneous and true common volume in situ measurements of temperature and turbulence supported by ground-based lidar observations reveal ... -
Ultrasonic properties of all-printed piezoelectric polymer transducers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)The ability of producing ultrasonic transducers from screen-printing has been explored experimentally, through printing and characterization of a large number of transducers. In an allprinted test design, 124 transducers with four different electrode sizes ranging from 1 to 4.9 mm2, were printed layer-by-layer on a high performance polyethyleneimine polymer. Inks from ferroelectric and conductive ... -
Enhanced EISCAT UHF backscatter during high-energy auroral electron precipitation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)Natural enhancements in the backscattered power of incoherent scatter radars up to 5 orders of magnitudes above the thermal backscatter are sometimes observed at high latitudes. Recently observations of enhancements in the backscattered power including a feature at zero Doppler shift have been reported. These enhancements are limited in altitude to tens of kilometers. The zero Doppler shift ... -
Observations of HF-induced instability in the auroral E region
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)Enhancements were observed in backscattered radar power during an ionospheric heating experiment from two distinct altitude regions in the auroral E region above Tromsø. For the experiment the EISCAT Tromsø heater was operated with O mode and X mode alternated at 4.04 MHz, close to the 3rd electron gyroharmonic. Ion-line data recorded with the EISCAT UHF radar reveal different temporal ...