Fakultet for naturvitenskap og teknologi: Nye registreringer

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    • Computational Fluid Dynamic Analysis of the Tesla Turbine 

      Strand, Cathrine; Eidesen, Hans-Kristian; Khawaja, Hassan Abbas (Conference object; Konferansebidrag, 2016-12-08)
      Serbian-born inventor Nikola Tesla invented the Tesla turbine and patented it in 1913. The Tesla turbine is unique in the sense that it does not have any blades, also referred to as “bladeless turbine”. The working was based on the establishment of the fluid boundary layer. The original Tesla turbine consisted of multiple smooth discs. With the passage of flow, a boundary layer establishes and skin ...

    • Study of Materials’ Impact Properties for Arctic Marine Structures 

      Xue, Hui; Khawaja, Hassan Abbas; Moatamedi, Mojtaba; Kwon, Young; Sun, Zhiheng (Conference object; Konferansebidrag, 2016-12)
      It is well understood that sea ice is one of the biggest problems for the safety and reliability of ships and marine structures operating in the Arctic. Specially designed ships, also known as ‘icebreakers’, are usually used to clear ice to make way for merchant and cruise ships. Even then, the ship’s staff must be extremely careful with speed and steering. Heavy impacts of ice result in fatigue and ...

    • Study of Ice Adhesion Behavior of SK One Component Polyurethane 

      Xue, Hui; Khawaja, Hassan Abbas; Moatamedi, Mojtaba; Sun, Zhiheng (Conference object; Konferansebidrag, 2016-12)
      Ice adhesion causes many serious problems such as aircraft accidents, navigational issues on ships, and power loss on wind turbines. These challenges are mainly associated with the acute behavior of ice adhesion. The ice adheres when water seeps into the microscopic pores of the material substrate and freezes, thereby, forming an interlocking mechanism. Therefore, surface roughness has a significant ...

    • Marketing structures and strategies of Nordic SME’s: A Norwegian case study 

      Ayele, Yonas Zewdu (Conference object; Konferansebidrag, 2016-10-10)

    • Wind speed and direction predictions by WRF and WindSim coupling over Nygårdsfjell 

      Bilal, Muhammad; Birkelund, Yngve; Solbakken, Kine (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 ...

    • Complete genome sequence of Halomonas sp. R5-57 

      Williamson, Adele Kim; De Santi, Concetta; Altermark, Bjørn; Karlsen, Christian; Hjerde, Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      The marine Arctic isolate Halomonas sp. R5-57 was sequenced as part of a bioprospecting project which aims to discover novel enzymes and organisms from low-temperature environments, with potential uses in biotechnological applications. Phenotypically, Halomonas sp. R5-57 exhibits high salt tolerance over a wide range of temperatures and has extra-cellular hydrolytic activities with several ...

    • Interpreting sea surface slicks on the basis of the normalized radar cross-section model using RADARSAT-2 copolarization dual-channel SAR images 

      Dmitry V., Ivonin; Skrunes, Stine; Brekke, Camilla; Ivanov, A. Yu. (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 ...

    • A polarizable continuum model for molecules at spherical diffuse interfaces 

      Di Remigio, Roberto; Mozgawa, Krzysztof; Cao, Hui; Weijo, Ville; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-22)
      We present an extension of the Polarizable Continuum Model (PCM) to simulate solvent effects at diffuse interfaces with spherical symmetry, such as nanodroplets and micelles. We derive the form of the Green’s function for a spatially varying dielectric permittivity with spherical symmetry and exploit the integral equation formalism of the PCM for general dielectric environments to recast the solvation ...

    • Wind Energy at Nygårdsfjellet – Norway. Wind field characterization and modelling 

      Bilal, Muhammad (Doctoral thesis; Doktorgradsavhandling, 2016-11-25)
      The research focuses on the characterization of wind flow over complex terrain of Nygårdsfjell and numerical wind flow modelling. In the context to research focus, the main contributions of this research thesis are within the following areas: Characterization of wind flow at the Nygårdsfjell wind farm, situated in the arctic circle in Norway. Wind data is collected from the anemometers installed on ...

    • Granskingsdilemmaer i tilsyn og kommisjon. En komparativ dokumentanalyse av Statens havarikommisjon for transport og Petroleumstilsynet 

      Krogsæter, Stig (Mastergradsoppgave; Master thesis, 2016-09-23)
      I denne oppgaven gjør jeg en komparativ dokumentanalyse av Statens havarikommisjon for transport (SHT) og Petroleumstilsynet (Ptil). Den undersøker hvordan rekke granskingsdilemmaer påvirker granskinger, ved å forklare hvordan disse dilemmaene påvirker granskingenes læringspotensial. Dilemmaene knytter seg til granskingenes mandat, metodikk og forklaringsmodell, uavhengighet, forebyggingstiltak samt ...

    • Ice sheet dynamics in the Brunt Basin, Weddell Sea, Antarctica, since the last glacial period 

      Sørli, Simon Helle (Master thesis; Mastergradsoppgave, 2016-11-15)
      High-resolution swath bathymetry, TOPAS sub-bottom profiles and four gravity cores from the Brunt Basin, southeastern Weddell Sea in Antarctica, were analysed with the purpose of reconstructing the ice sheet dynamics since the last glacial. Data collection was carried out by the British Antarctic Survey (BAS) and data analyses were carried out in a collaboration between the Department of Geosciences ...

    • Bretilbaketrekningshistorie og landformer foran Steindalsbreen, Lyngen, Troms 

      Nilsen, Carina (Master thesis; Mastergradsoppgave, 2016-06-15)
      Steindalen er lokalisert sør på Lyngenhalvøya, i Troms fylke. Steindalsbreen er en av de lettest tilgjengelige breer i området. Dette gjør breen til et yndet turmål, men det gjør det også lettere å studere en bre på nært hold. Undersøkelse av Steindalsbreen har foregått ved hjelp av feltturer til området, ved å studere foto og flybilder over området og ved å sammenstille data samlet over mange år, ...

    • Wind resource assessment using mesoscale modelling. A case study at the potential wind farm site Rieppi 

      Blæsterdalen, Torgeir (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 

      Decristoforo, Gregor (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 

      Ingvaldsen, Martin (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 ...

    • RAM Analysis of Oil and Gas Production Facilities Operating in the Arctic offshore: Expert Judgements and Operating Conditions 

      Naseri, Masoud (Doctoral thesis; Doktorgradsavhandling, 2016-08-31)
      The Arctic offshore has a sensitive environment and is associated with a range of harsh operating conditions with considerable year-round variations. Such conditions can adversely affect the reliability, availability, and maintainability (RAM) of oil and gas (O&G) production facilities in different ways. One of the main challenges in RAM analysis of Arctic offshore O&G facilities is the lack of ...

    • Carbon Nanotube Spectrally Selective Solar Thermal Absorbers 

      Chen, Zhonghua (Doctoral thesis; Doktorgradsavhandling, 2016-10-04)
      The main objectives of this work were to investigate a) the feasibility of depositing multi-walled carbon nanotubes (MWCNTs) homogeneously on metal substrates by electrophoresis and b) the performance of MWCNT coatings as spectrally selective absorbers. Stable aqueous MWCNT suspensions were prepared and employed in electrophoretic deposition (EPD) of MWCNT coatings on aluminum substrates. The surface ...

    • Improving Latency in Mobile/Cloud Applications 

      Pettersen, Robert Molund (Doctoral thesis; Doktorgradsavhandling, 2016-08-25)
      Smartphones are becoming comparable to desktop computers in terms of computational power, and offer diverse applications ranging from social media and gaming, to multimedia and banking. A particular class of mobile applications, mobile/cloud applications, are tightly coupled with the cloud. While executing on the mobile device, they communicate frequently with the cloud for crucial functionality. Use ...

    • Machine Learning using Principal Manifolds and Mode Seeking 

      Myhre, Jonas Nordhaug (Doctoral thesis; Doktorgradsavhandling, 2016-10-14)
      A wide range of machine learning methods have taken advantage of density estimates and their derivatives, including methodology related to principal manifolds and mode seeking, finding use in a number of real applications. However, research concerned with improving density derivative estimation and its practical use have received relatively limited attention. Also, the fact that the derivatives ...

    • Simplified Representation of Degradation, Inspection and Maintenance in a Strategic Decision Support Tool for Offshore Wind Operation and Maintenance 

      Hussain, Azeem (Master thesis; Mastergradsoppgave, 2016-08-09)
      The global demand for energy is increasing in the current scenario of industrial development and offshore wind energy has a great potential to become a key player specifically in Europe’s renewable energy future. Naturally the flow of wind in offshore environments is more consistent and also the average wind velocity is higher than onshore. However, the cost of electricity generated from offshore ...