Fakultet for naturvitenskap og teknologi: Nye registreringer
Viser treff 3361-3380 av 5336
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Geometry and kinematic evolution of ductile shear zones in the Ersfjord Granite (1.79 Ga), West Troms Basement Complex: A Svecofennian accretionary thrust system
(Master thesis; Mastergradsoppgave, 2018-11-26)The Ersfjord Granite is a 1.79 Ga felsic intrusion in the geological region of West Troms Basement Complex (WTBC). Its intrusion history and evolution relative to surrounding Neoarchean TTG-gneisses has until now been poorly understood, providing the basis for this thesis. The present study focuses on internal deformation structures in the granite, as well as the nearby Gråtind Migmatite, in order ... -
Climate controlled sedimentary processes in the Riiser Larsen Sea offshore Queen Maud Land, Antarctica
(Master thesis; Mastergradsoppgave, 2018-11-29)Multi-proxy analysis of gravity core PS56/029-1 have been performed in order to describe sedimentary processes and dynamics under pelagic, turbiditic and contouritic influences. The purpose is to reconstruct climate-controlled environmental change in the Riiser Larsen Sea, Antarctica, through past glacial/interglacial cycles. The gravity core was retrieved during expedition ANTARKTIS XVII/2 of R/V ... -
A refined late-Cryogenian – Ediacaran Earth history of South China: phosphorous-rich marbles of the Dabie and Sulu orogens
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-02)The late-Cryogenian – Ediacaran geological framework for South China is constructed principally from sedimentary successions preserved in the central and western regions of the Yangtze Block. New stratigraphic and carbonate-carbon isotope data allow us to extend that framework into the exhumed HP-UHP subduction complexes of the eastern Dabie and Sulu orogens that separate the South and North China ... -
Derivation of vertical wavelengths of gravity waves in the MLT-region from multispectral airglow observations
(Journal article; Tidsskriftartikkel; Peer reviewed; Preprint; Manuskript, 2018-03-06)<p>We present the derivation of gravity wave vertical wavelengths from OH airglow observations of different vibrational transitions. It utilizes small phase shifts regularly observed between the OH(3-1) and OH(4-2) intensities in the spectra of the GRIPS (GRound-based Infrared P-branch Spectrometer) instruments, which record the OH airglow emissions in the wavelength range from 1.5 μm to 1.6 μm ... -
Kayas identitet og valgets kval
(Chronicle; Kronikk, 2017-08-21)<i>Ingress</i>: Det Kayas identitet viser oss er for det første at for å redusere utslippene må vi gjøre noe med befolkningsveksten og/eller en eller flere av de tre intensitetene. -
Heterocyclic cellular lipid peroxidation inhibitors inspired by the marine antioxidant barettin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-22)The marine environment remains a rich source for the discovery and development of novel bioactive compounds. The present paper describes the design, synthesis and biological evaluation of a library of small molecule heterocyclic mimetics of the marine 2,5-diketopiperazine barettin which is a powerful natural antioxidant. By mainly focusing on the influence from the brominated indole and heterocyclic ... -
Methane at Svalbard and over the European Arctic Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-05)Methane (CH<sub>4</sub>) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH<sub>4</sub> sources is essential for effective climate change mitigation. Here we report observations of the CH<sub>4</sub> mixing ratios measured at the Zeppelin Observatory (Svalbard) in the Arctic and aboard the research vessel (RV) Helmer Hanssen ... -
Development of strategic asset management planning in the petroleum industry
(Tidsskriftsartikkel; Journal article; Tidsskriftartikkel; Peer reviewed, 2017)<i>Purpose</i> – Due to the certain risk carried in offshore petroleum installations, the integrity of these installations needs to be maintained at all times. Thus, asset integrity management (AIM) needs to be formulated and monitored to achieve the integrity objective. The purpose of this paper is to study the practices and progression of strategic AIM planning in the petroleum industry. ... -
Comment on“The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-30)<p><i>Introduction</i>: The discussed area has been investigated since the 1960s. Scientists of the Norwegian Polar Institute, the Cambridge scholar environment, the University of Münster and others have mapped, described, interpreted and contributed to the discussion through decades. Very little of this is reflected in the paper by Braathen, Osmundsen, Maher, and Ganerød, (2018). A discussion of ... -
Scenario-based modelling of the potential for solar energy charging of electric vehicles in two Scandinavian cities
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-19)In order to contribute to the reduction of greenhouse gas emissions, electric vehicles (EVs) should be charged using electricity from renewable energy sources. This paper describes a study of photovoltaics (PV) utilization for EV charging in two Scandinavian cities: Tromsø in Norway and Uppsala in Sweden, with the objective to evaluate self-sufficiency and self-consumption. The suitable areas ... -
Advancing Segmentation and Unsupervised Learning Within the Field of Deep Learning
(Doctoral thesis; Doktorgradsavhandling, 2018-10-19)Due to the large improvements that deep learning based models have brought to a variety of tasks, they have in recent years received large amounts of attention. However, these improvements are to a large extent achieved in supervised settings, where labels are available, and initially focused on traditional computer vision tasks such as visual object recognition. Specific application domains that ... -
CFD modelling of pressure and shear rate in torsionally vibrating structures using ANSYS CFX and COMSOL Multiphysics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018)This paper discusses numerical methodologies to simulate micro vibrations on a nontrivial torsionally oscillating structure. The torsional structure is the tip of a viscosity-density sensor using micro vibrations to measure the fluid properties. A 2D transient simulation of the fluid domain surrounding the tip of the sensor has been conducted in ANSYS CFX and COMSOL Multiphysics software. ANSYS CFX ... -
Terrenganalyse og 3D snøskredsimuleringer for plassering av radar for snøskredvarsling
(Master thesis; Mastergradsoppgave, 2018-10-09)Etter flere ulykker knyttet til snøskred på Europavei 8 i Lavangsdalen i Troms de siste årene, har Statens vegvesen gått inn for å bedre skredsikringen langs den 18 km lange dalen. Hovedformålet med denne masteroppgaven er å komme med innspill til hensiktsmessig plassering av automatiske overvåkningsanlegg for snøskred ved fire avgrensede strekninger langs vegen: Hestvollan, Sarasteinen, Stortinden ... -
OBS Data Analysis to Quantify Gas Hydrate and Free Gas in the South Shetland Margin (Antarctica)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-25)The presence of a gas hydrate reservoir and free gas layer along the South Shetland margin (offshore Antarctic Peninsula) has been well documented in recent years. In order to better characterize gas hydrate reservoirs, with a particular focus on the quantification of gas hydrate and free gas and the petrophysical properties of the subsurface, we performed travel time inversion of ocean-bottom ... -
Ice‐rafting patterns on the western Svalbard slope 74–0 ka: interplay between ice‐sheet activity, climate and ocean circulation
(Journal article; Tidsskriftartikkel, 2018-11-14)The distribution of ice‐rafted detritus (IRD) is studied in three cores from the western Svalbard slope (1130–1880 m water depth, 76–78°N) covering the period 74–0 ka. The aim was to provide new insight into the dynamics of the Svalbard–Barents Sea Ice Sheet during Marine Isotope Stages (MIS) 4–1 to get a better understanding of ice‐sheet interactions with changes in ocean circulation and climate ... -
Rigidity of 2-step carnot groups
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-19)In the present paper we study the rigidity of 2-step Carnot groups, or equivalently, of graded 2-step nilpotent Lie algebras. We prove the alternative that depending on bi-dimensions of the algebra, the Lie algebra structure makes it either always of infinite type or generically rigid, and we specify the bi-dimensions for each of the choices. Explicit criteria for rigidity of pseudo Hand <i>J</i>-type ... -
Reconstructing the Paleoproterozoic sulfur cycle: Insights from the multiple sulfur isotope record of the Zaonega Formation, Karelia, Russia
(Doctoral thesis; Doktorgradsavhandling, 2018-11-08)Earth’s oxygen-rich atmosphere and its capacity to sustain complex life is the most paramount feature that distinguishes Earth from all other planets. The irreversible oxygenation of atmosphere occurred about half way through Earth’s history at ~2.3 Ga (the Great Oxidation Event – GOE) when for the first-time photosynthetic oxygen production surpassed the consumption by chemical reactions allowing ... -
Thermography and tensile tests of steel samples. Study of material properties and internal friction effects
(Master thesis; Mastergradsoppgave, 2018-06-01)The thesis presents analysis of material properties and internal effects in steel samples, with varying temperatures. Uniaxial tensile tests were conducted in both room temperature and low temperatures, to generate graphical measures of the mechanical properties. The steel samples were monitored with thermography throughout the course of the tensile tests, to investigate the heat generation associated ... -
Friction tests on polyurethane and concrete. Rolling friction tests and sliding friction tests on anti-abrasion polyurethane, anti-seepage polyurethane and concrete.
(Master thesis; Mastergradsoppgave, 2018-06-01)The climate in arctic areas of the world is a challenge for airports. Snow and ice accumulates on the runways, forcing airports to close for snow clearing. Pilots need to know that the friction is at a respectable level before they land, and may have to return if not. This thesis looked at a polymer called polyurethane, and if this material could be used as a new runway material, considering both ... -
Oil Spill Preparedness and Response in the Arctic. The effect of low temperature on oil spill response operations in the Arctic with respect to overall equipment effectiveness
(Master thesis; Mastergradsoppgave, 2018-06-02)Effectiveness is an important term in oil spill response operations. Literature often relate to the level of effectiveness connected to either mechanical containment and recovery, in-situ burning or chemical dispersant application. The term effectiveness in oil spill response operations can be related to existing theory and the perspective of Overall Equipment Effectiveness (OEE). The perspective ...