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norskBlar i tittel Fakultet for naturvitenskap og teknologi
Viser treff 1440-1459 av 4753
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F-region electron heating by X-mode radiowaves in underdense conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2009) -
Facile Supramolecular Engineering of Porphyrin cis Tautomers: The Case of β-Octabromo-meso-tetraarylporphyrins
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-02)A porphyrin cis tautomer, where the two central NH protons are on adjacent pyrrole rings, has long been invoked as an intermediate in porphyrin tautomerism. Only recently, however, has such a species been isolated and structurally characterized. Thus, single-crystal X-ray structure determinations of two highly saddled free-base porphyrins, β-heptakis(trifluoromethyl)-meso-tetrakis(p-fluorophenyl)porphyrin, ... -
Factorisation patterns of division polynomials
(Journal article; Tidsskriftartikkel; Peer reviewed, 2004-05)The choice of an elliptic curve for the implementa- tion of an elliptic curve cryptosystem requires count- ing the number of points on such a curve over a fi- nite field. An improvement of Schoof’s algorithm for counting the number of rational points on an ellip- tic curve defined over a finite field takes advantage of some factor of the division polynomials. In this paper, we study the ... -
Factors controlling the net ecosystem production of cryoconite on Western Himalayan glaciers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-07)In situ experiments were conducted to determine the net ecosystem production (NEP) in cryoconite holes from the surface of two glaciers (Patsio glacier and Chhota Shigri glacier) in the Western Himalaya during the melt season from August to September 2019. The study aimed to gain an insight into the factors controlling microbial activity on glacier surfaces in this region. A wide range of parameters, ... -
Factors influencing the time required to don thermal protective immersion suits correctly
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-10)The cold environment in polar regions introduces additional challenges when abandoning passenger vessels and offshore facilities. The International Maritime Organization Polar Code requires vessels operating in polar regions to be equipped with approved thermal protective immersion suits (TPIS) that can be donned unassisted within 120 s. As time is critical during an evacuation, quantifying the Net ... -
Failure intensity of offshore power plants under varying maintenance policies
(Journal article; Peer reviewed; Tidsskriftartikkel, 2019-01-06)System reliability of an offshore power plant with several gas turbine engines is analyzed in this study to understand the failure intensity of a selected gas turbine engines under varying maintenance activities. A set of event data of a selected gas turbine engine is considered to identify system failure intensity levels, where unknown maintenance actions were implemented (i.e. various repairs ... -
FAIR+E pathogen data for surveillance and research: lessons from COVID-19
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-21)The COVID-19 pandemic has exemplified the importance of interoperable and equitable data sharing for global surveillance and to support research. While many challenges could be overcome, at least in some countries, many hurdles within the organizational, scientific, technical and cultural realms still remain to be tackled to be prepared for future threats. We propose to (i) continue supporting global ... -
Familiarisering av dekksoffiserer om bord på offshore-forsyningsfartøy. En case-studie
(Master thesis; Mastergradsoppgave, 2014-06-01)Oppgaven tar for seg familiarisering av dekksoffiserer om bord på offshore-forsyningsfartøy. Valg av tema for oppgaven ble gjort på bakgrunn av funn fra Batalden og Sydnes (2014) sin studie av ulykkesårsaker i britisk farvann. ISM-koden stiller krav til at rederiene utarbeider sikkerhetsstyringssystemer, dette som et ledd i IMO sitt arbeid med å øke sikkerheten til sjøs. Batalden og Sydnes (2014) ... -
Families of Gröbner Degenerations, Grassmannians and Universal Cluster Algebras
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-10)Let V be the weighted projective variety defined by a weighted homogeneous ideal J and C a maximal cone in the Gröbner fan of J with m rays. We construct a flat family over A<sup>m</sup> that assembles the Gröbner degenerations of V associated with all faces of C. This is a multi-parameter generalization of the classical one-parameter Gröbner degeneration associated to a weight. We explain how our ... -
FANet: A Feedback Attention Network for Improved Biomedical Image Segmentation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-25)The increase of available large clinical and experimental datasets has contributed to a substantial amount of important contributions in the area of biomedical image analysis. Image segmentation, which is crucial for any quantitative analysis, has especially attracted attention. Recent hardware advancement has led to the success of deep learning approaches. However, although deep learning models are ... -
Faraday rotation fluctuations of MESSENGER radio signals through the equatorial lower corona near solar minimum
(Journal article; Peer reviewed; Tidsskriftsartikkel, 2016-12-26)Faraday rotation (FR) of transcoronal radio transmissions from spacecraft near superior conjunction enables study of the temporal variations in coronal plasma density, velocity, and magnetic field. The MESSENGER spacecraft 8.4 GHz radio, transmitting through the corona with closest line-of-sight approach 1.63–1.89 solar radii and near-equatorial heliolatitudes, was recorded soon after the deep ... -
Fast and slow components of interstadial warming in the North Atlantic during the last glacial
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-13)The abrupt nature of warming events recorded in Greenland ice-cores during the last glacial has generated much debate over their underlying mechanisms. Here, we present joint marine and terrestrial analyses from the Portuguese Margin, showing a succession of cold stadials and warm interstadials over the interval 35–57 ka. Heinrich stadials 4 and 5 contain considerable structure, with a short ... -
Fast estimation of ocean background reflectivity in synthetic aperture radar images
(Master thesis; Mastergradsoppgave, 2015-06-02)Several ship detection algorithms have been developed over the years, where some of the most commonly used are the constant false alarm rate (CFAR) algorithms. There are challenges to the existing algorithms, both when it comes to processing time and difficult scene situations, such as heterogeneous ocean clutter and multiple targets. Existing algorithms that are equipped to handle situations ... -
Faster decline and higher variability in the sea ice thickness of the marginal Arctic seas when accounting for dynamic snow cover
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-04)Mean sea ice thickness is a sensitive indicator of Arctic climate change and is in long-term decline despite significant interannual variability. Current thickness estimations from satellite radar altimeters employ a snow climatology for converting range measurements to sea ice thickness, but this introduces unrealistically low interannual variability and trends. When the sea ice thickness in the ... -
Faszination Nano-Staubteilchen im Kosmos - Astronomie als Puzzle
(Conference object; Konferansebidrag, 2018) -
FAT: A framework for automated regression testing of protocol stacks
(Master thesis; Mastergradsoppgave, 2003-12-15)Software systems today are becoming larger and more complex, resulting in a growing need for good and efficient testing routines. An approach used by several software developers is to automate the test process. Test automation has the benefits that it reduces the time of the testing process and that automated tests are more accurate and precise than manual tests. <br /><br /> Manufacturers who ... -
The Fate of Nanodust near the Sun - Comparison of Sputtering and Sublimation lifetimes during CMEs
(Conference object; Konferansebidrag, 2018)The dust environment in the inner Solar system has not been probed so far, but ESA’s Solar Orbiter (2020) and NASA’s Parker Solar Probe (2018) are about cross the inner solar system. From [1] we expect a layer of trapper Nanodust around the Sun. [2] investigated the interaction of grains with the Solar wind. But what is the dust’s fate when they are struck by a Coronal Mass Ejection (CME). Are they ... -
The fate of plastic in the ocean environment – a minireview
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-14)The presence of plastics in the marine environment poses a threat to ocean life and has received much scientific and public attention in recent years. Plastics were introduced to the market in the 1950s and since then, global production figures and ocean plastic littering have increased exponentially. Of the 359 million tonnes (Mt) produced in 2018, an estimated 14.5 Mt has entered the ocean. In ... -
Fatigue Awareness. Introducing fatigue awareness devices as a part of FRMS in an airline
(Master thesis; Mastergradsoppgave, 2016-06-01)Fatigue has become more of broad and current interest, and has been claimed to be a contributing factor in several aviation accidents and incidents (European Cockpit Association, 2010; Flin, 2008). The International Air Transport Association (ICAO) changed one of their annexes in 2012, allowing fatigue risk management systems (FRMS) instead of prescriptive flight time limitations. From 2018 there ... -
Fatigue i norsk flygeledertjeneste
(Master thesis; Mastergradsoppgave, 2022-05-31)Det siste århundre har det vært stort fokus på forskning, om fatigue. Allerede i 1990 så satte FAA fatigue som en av de store årsakene man måtte bekjempe for å gjøre luftfarten trygg. Etter dette har det blitt gjennomført mye forskning blant piloter. Forskning frem til i dag har hatt lite fokus på fatigue blant flygeledere. Derfor har denne masteroppgaven sett på fatigue blant flygeldere, og hvordan ...
