Institutt for fysikk og teknologi: Recent submissions
Now showing items 1121-1140 of 1407
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Stochastic modelling of intermittent fluctuations in the scrape-off layer: Correlations, distributions, level crossings, and moment estimation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05)A stochastic model is presented for intermittent fluctuations in the scrape-off layer of magnetically confined plasmas. The fluctuations in the plasma density are modeled by a super-position of uncorrelated pulses with fixed shape and duration, describing radial motion of blob-like structures. In the case of an exponential pulse shape and exponentially distributed pulse amplitudes, predictions are ... -
Effects of substorm electrojet on declination along concurrent geomagnetic latitudes in the northern auroral zone
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-02)The geomagnetic field often experiences large fluctuations, especially at high latitudes in the auroral zones. We have found, using simulations, that there are significant differences in the substorm signature, in certain coordinate systems, as a function of longitude. This is confirmed by the analysis of real, measured data from comparable locations. Large geomagnetic fluctuations pose ... -
Delt situasjonsforståelse under søk og redning i nordområdene
(Research report; Forskningsrapport, 2016-05-03)Prosjektets mål er å bidra til økt kunnskap om hvordan etablere delt situasjonsforståelse mellom sentrale aktører innen SAR i Nordområdet. Prosjektgruppa har arbeidet ut ifra en menneske-teknologi-organisasjon (MTO) tilnærming og hvor vi har sett på <br>1) menneskelige og organisatoriske faktorer og <br>2) tekniske faktorer som virker inn på etableringen av delt situasjonsforståelse mellom aktører.<br> ... -
A Brief Look at the Performance of PV in Norway
(Master thesis; Mastergradsoppgave, 2016-12-15)In the past years the Norwegian PV market has grown substantially. The importance of data on how PV systems perform in Norway is therefore also increasing. In this thesis several Norwegian PV systems are analyzed mainly in terms of annual specific yields. The systems are located in western and southeastern Norway and near horizontal, tilted and vertical modules are looked at. Results show pretty ... -
Scanning acoustic microscopy—A novel noninvasive method to determine tumor interstitial fluid pressure in a xenograft tumor model
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-22)Elevated tumor interstitial fluid pressure (TIFP) is a prominent feature of solid tumors and hampers the transmigration of therapeutic macromolecules, for example, large monoclonal antibodies, from tumor-supplying vessels into the tumor interstitium. TIFP values of up to 40 mm Hg have been measured in experimental solid tumors using two conventional invasive techniques: the wick-in-needle and the ... -
Amplitude and size scaling for interchange motions of plasma filaments
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-07)The interchange dynamics and velocity scaling of blob-like plasma filaments are investigated using a two-field reduced fluid model. For incompressible flows due to buoyancy, the maximum velocity is proportional to the square root of the relative amplitude and the square root of its cross-field size. For compressible flows in a non-uniform magnetic field, this square root scaling only holds ... -
Wind speed and direction predictions by WRF and WindSim coupling over Nygårdsfjell
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)In this study, the performance of the mesoscale meteorological Weather Research and Forecast (WRF) model coupled with the microscale computational fluid dynamics based model WindSim is investigated and compared to the performance of WRF alone. The two model set-ups, WRF and WRF-WindSim, have been tested on three high-wind events in February, June and October, over a complex terrain at the ... -
Interpreting sea surface slicks on the basis of the normalized radar cross-section model using RADARSAT-2 copolarization dual-channel SAR images
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-24)A simple automatic multipolarization technique for discrimination of main types of thin oil films (of thickness less than the radio wave skin depth) from natural ones is proposed. It is based on a new multipolarization parameter related to the ratio between the damping in the slick of specially normalized resonant and nonresonant signals calculated using the normalized radar cross-section model ... -
Wind resource assessment using mesoscale modelling. A case study at the potential wind farm site Rieppi
(Master thesis; Mastergradsoppgave, 2016-06-01)The growing wind power industry, increased occurrence of extreme weather, and the need for becoming independent of fossil fuels motivate the research on accurate simulation of near-surface wind. The aim of this study is wind resource assessment at the potential wind park site Rieppi, using two on-site measurement masts, simulations from the Weather Research and Forecasting (WRF) model, and ERA-Interim ... -
Numerical computations of turbulent motions in magnetized plasmas
(Master thesis; Mastergradsoppgave, 2016-05-18)Intermittent fluctuations and turbulence-induced transport of magnetically confined fusion plasmas are investigated by numerical computations. A reduced fluid model describing the evolution of plasma pressure and electric drift vorticity in a two-dimensional plane perpendicular to the magnetic field is derived. A numerical simulation code implemented on graphical processing units is presented. We ... -
Sensitivity to pressure and methane of a cryptophane-A doped polymer
(Master thesis; Mastergradsoppgave, 2015-12-15)The principle focus of this thesis is the characterization of an on-chip methane sensor based on a waveguide interferometer. It incorporates cryptophane-A molecules in the waveguide cladding to enhance sensitivity and selectivity towards methane. First, the sensor was characterized for sensitivities to ambient conditions, in particular its temperature and pressure sensitivity. The measurement ... -
Rib waveguides for trapping and transport of particles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-23)Rib waveguides are investigated as an alternative to strip waveguides for planar trapping and transport of microparticles. Microparticles are successfully propelled along the surface of rib waveguides and trapped in the gap between opposing rib waveguides. The trapping capabilities of waveguide end facets formed by a single and opposing waveguide geometries are investigated. The slab beneath a rib ... -
An evaluation of International Reference Ionosphere electron density in the polar cap and cusp using EISCAT Svalbard radar measurements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-13)Incoherent scatter radar measurements are an important source for studies of ionospheric plasma parameters. In this paper the EISCAT Svalbard radar (ESR) long-term database is used to evaluate the International Reference Ionosphere (IRI) model. The ESR started operations in 1996, and the accumulated database up to 2012 thus covers 16 years, giving an overview of the ionosphere in the polar cap and ... -
Integrated Monitoring of Mola mola Behaviour in Space and Time
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-05)Over the last decade, ocean sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of fine-scale (< 10 m) behaviour of sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both the movements and the contextual environment ... -
Retrieval of sodium number density profiles in the mesosphere and lower thermosphere from SCIAMACHY limb emission measurements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-28)An algorithm has been developed for the retrieval of sodium atom (Na) number density on a latitude and altitude grid from SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) limb measurements of the Na resonance fluorescence. The results are obtained between 50 and 150 km altitude and the resulting global seasonal variations of Na are analyzed. The retrieval approach ... -
Time-lapse seismic analysis of focused fluid flow on the Vestnesa Ridge
(Master thesis; Mastergradsoppgave, 2016-06-01)The Vestnesa Ridge is a large sediment drift at water depths of 1200-1300 meter and is the northernmost known gas hydrate province that exists along the Arctic continental margin. Several pockmarks connected to vertical fluid flow features are present at the crest of the Vestnesa Ridge. The fluid flow pierce through the gas hydrate stability zone and interrupt the bottom simulating reflection (BSR) ... -
Depositional environments of the Upper Triassic Snadd Formation on the Loppa High, SW Barents Sea
(Master thesis; Mastergradsoppgave, 2016-06-01)This thesis has focused on the depositional environments of the Upper Triassic Snadd Formation. This formation covers the time-period Ladinian to early Norian with multiple marine regressions and transgressions, resulting in depositional environments ranging from offshore marine shelf to a coastal plain. A 3D seismic dataset and its correlating well have been studied and a refined seismic stratigraphic ... -
Repeatability of P-Cable 3D seismic data
(Master thesis; Mastergradsoppgave, 2016-05-31)The use of 4D time-lapse seismic data is a viable technology for monitoring fluid changes in the subsurface using conventional data, e.g. reservoir exploitation and CO2 storage. In this master thesis, the potential for using high-resolution P-Cable 3D seismic data for 4D time-lapse studies has been evaluated. The P-Cable 3D seismic system is a versatile, lightweight system which employs 24 short ... -
Seabed depressions in the Ingøydjupet Trough and their relation to buried canyons on the Loppa High, Barents Sea
(Master thesis; Mastergradsoppgave, 2016-06-13)Large seabed depressions in the Ingøydjupet Trough have previously been interpreted to be formed by sub-glacial melt-water. However, fluid migration and gas expulsion occur over large parts of the Barents Sea, which are frequently associated with seabed depressions. This thesis studies how the seabed depressions are related to sub-surface canyons on the southern part of the Loppa High, SW Barents ... -
Renewable Energy Resources: A Case Study on Asko Nord AS
(Master thesis; Mastergradsoppgave, 2016-06-01)Asko Nord AS i a business located in Ramfjorden just outside of Tromsø. In this theses, their potential to produce electricity from renewable resources at their location is investigated. Wind around the building is to find suitable locations for wind turbines, and to estimate the wind at the wind turbines. The calculations show that in a feasible estimate the wind is able to produce 439 kwh ...