Now showing items 827-846 of 1261

    • The optical afterglow and host galaxy of GRB 000926 

      Fynbo, J.U.; Østensen, R.; Gorosabe, J.; Solheim, Jan Erik; Dall, T.H.; Hjorth, J.; Pedersen, H.; Andersen, M.I.; Møller, P.; Holland, S.; Smail, I.; Kobayashi, N.; Rol, E.; Vreeswijk, P.; Vrba, F.; Burud, I.; Jensen, B.L.; Henden, A.; Thomsen, B.; Canzian, B.; Castro Cer´on, J.M.; Castro-Tirado, A.J.; Cline, T.; Goto, M.; Greiner, J.; Hanski, M.T.; Hurley, K.; Pursimo, T.; Lund, N.; Tanvir, N.; Terada, H. (Journal article; Tidsskriftartikkel, 2001-04-11)
      We present the discovery of the Optical Transient (OT) of the long–duration gamma-ray burst GRB 000926. The optical transient was detected independently with the Nordic Optical Telescope and at Calar Alto 22.2 hours after the burst. At this time the magnitude of the transient was R = 19.36. The transient faded with a decay slope of about 1.7 during the first two days after which the slope increased ...
    • Optical nanoscopy of tissue sections 

      Villegas Hernandez, Luis Enrique (Master thesis; Mastergradsoppgave, 2018-05-28)
      The study of organ tissues, namely, histology, is essential for clinical medicine, as it allows the identification of a wide range of diseases. Traditionally, two major techniques, optical and electron microscopy, have been used for morphological observation of tissue sections. Optical microscopy (OM) allows for fast-acquisition high-throughput imaging, at the expense of diffraction-limited resolution ...
    • Optical Remote Sensing of Oil Spills by using Machine Learning Methods in the Persian Gulf: A Multi-Class Approach 

      Evenseth, Martin H. (Master thesis; Mastergradsoppgave, 2023-06-15)
      Marine oil spills are harmful for the environment and costly for society. Coastal areas are particularly vulnerable since they provide habitats for organisms, animals and marine ecosystems. This thesis studied machine learning methods to classify thick oil in a multi-class case, using remotely sensed multi-spectral data in the Persian Gulf. The study area covers a large area between United Arab ...
    • Optical transport, lifting and trapping of micro-particles by planar waveguides 

      Helle, Øystein Ivar; Ahluwalia, Balpreet Singh; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-03)
      Optical waveguides can be used to trap and transport micro-particles. The particles are held close to the waveguide surface by the evanescent field and propelled forward. We propose a new technique to lift and trap particles above the surface of the waveguides. This is made possible by a gap between two opposing, planar waveguides. The field emitted from each of the waveguide ends diverge fast, away ...
    • Optical trapping and propulsion of red blood cells on waveguide surfaces 

      Ahluwalia, Balpreet Singh; Mccourt, peter anthony; Huser, Thomas Rolf; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
    • Optical trapping in air on a single interference fringe 

      Schäpers, Aaron; Hellesø, Olav Gaute; Fick, Jochen (Journal article; Tidsskriftartikkel, 2023)
      Stable and reproducible trapping in air of 1 µm and 500 nm dielectric particles has been realized using a dual beam optical fiber tweezers with cleaved commercial single mode fibers. The influence of the interference fringes of the two coherent and counter-propagating trapping beam is investigated by controlling the fringe visibility. Optical trapping on a series of upto10 fringes or trapping on ...
    • Optical Trapping, Levitation and Tracking of Microparticles Using Waveguides 

      Helle, Øystein Ivar (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. ...
    • OptiJ: Open-source optical projection tomography of large organ samples 

      Vallejo Ramirez, Pedro P.; Zammit, Joseph; Vanderpoorten, Oliver; Fergus, Riche; Blé, Francois-Xavier; Zhou, Xiao-Hong; Spiridon, Bogdan; Valentine, Christopher; Spasov, Simeon E.; Oluwasanya, Pelumi W.; Goodfellow, Gemma; Fantham, Marcus J.; Siddiqui, Omid; Alimagham, Farah; Robbins, Miranda; Stretton, Andrew; Simatos, Dimitrios; Hadeler, Oliver; Rees, Eric J.; Ströhl, Florian; Laine, Romain F.; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-30)
      The three-dimensional imaging of mesoscopic samples with Optical Projection Tomography (OPT) has become a powerful tool for biomedical phenotyping studies. OPT uses visible light to visualize the 3D morphology of large transparent samples. To enable a wider application of OPT, we present OptiJ, a low-cost, fully open-source OPT system capable of imaging large transparent specimens up to 13 mm tall ...
    • An Optimal Decision-Tree Design Strategy and Its Application to Sea Ice Classification from SAR Imagery 

      Lohse, Johannes; Doulgeris, Anthony Paul; Dierking, Wolfgang Fritz Otto (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-03)
      We introduce the fully automatic design of a numerically optimized decision-tree algorithm and demonstrate its application to sea ice classification from SAR data. In the decision tree, an initial multi-class classification problem is split up into a sequence of binary problems. Each branch of the tree separates one single class from all other remaining classes, using a class-specific selected feature ...
    • Optimal sizing and placement of Electrical Vehicle charging stations to serve Battery Electric Trucks 

      Isaksen, Ole-André (Master thesis; Mastergradsoppgave, 2023-06-01)
      For Norway to reach the emission limits in the Paris Agreement, a substantial amount of CO2 must be reduced. Road traffic alone accounts for a high percentage of the total emissions during 2021. This thesis will focus on electrifying the transport sector and analyzing charging infrastructure for heavy-duty electric vehicles. New charging infrastructure for heavy-duty Electric Vehicles (EVs) provides ...
    • Optimization of a polymer layer highly doped with Cryptophane-A for methane sensing 

      Yadav, Mukesh (Master thesis; Mastergradsoppgave, 2017-05-15)
      The main objective of this thesis is to optimize the thickness of sensitive polymer layer highly doped with Cryptophane-A for methane pre-concentration and to make the existing sensor more stable and selective towards methane. In recent years, methane detection has become a hot topic due to the strong impact of methane on the global warming and the climate change. There has also been rising ...
    • Optimization of wind turbine location in urban environment 

      Hågbo, Trond-Ola (Master thesis; Mastergradsoppgave, 2017-06-01)
      Making energy clean, reliable and readily available is essential for fighting climate change and to supply an ever-rising global power demand. The aim of the study is to identify optimal locations for a wind turbine to be joined to a small-scale hybrid system at the main campus of UiT – The Arctic University of Norway. To identify feasible areas for maximizing electric power production, techniques ...
    • Optisk resonans i mikrokuler av glass med høy brytningsindeks 

      Husabø, Bjarne Janson (Master thesis; Mastergradsoppgave, 2009-06-15)
      I denne oppgaven har vi sett på effekten av lys som kobles fra en bølgeleder inn i optiske mikrokuler av høyindeksglass. Vi har studert Q-faktorer, og funnet at disse er lavere for kuler omgitt av vann enn tørre kuler, men at forskjellen er mindre enn mellom individuelle kuler. Vi har observert høyere ordens resonanser i kuler med større diameter. Vi har også forsøkt å utnytte resonans til å flytte ...
    • Optiske bølgeledere av silisium-rik nitrid for manipulering av mikro- og nanopartikler 

      Nermo, Thomas (Master thesis; Mastergradsoppgave, 2007-06-01)
      Målet med denne oppgaven er å karakterisere bølgeledere av silisium-rik nitrid, SiRN, med hensyn på koblingstap, propagasjonstap, tall på modi og feltfordeling. Det skal gjøres forsøk på å redusere tapet mest mulig ved å prøve ut forskjellige måter å koble inn lys og forbedre kuttingen av bølgelederene. Det skal også gjøres forsøk på å finne tykkelse og brytningsindeks på bølgelederene ved hjelp av ...
    • Organization of the magnetosphere during substorms 

      Zivkovic, Tatjana; Rypdal, Kristoffer (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      The change in degree of organization of the magnetosphere during substorms is investigated by analyzing various geomagnetic indices, as well as interplanetary magnetic field z-component and solar wind velocity x-component. We conclude that the magnetosphere self-organizes globally during substorms, but neither the magnetosphere nor the solar wind become more predictable in the course of a substorm. ...
    • Origin and accumulation mechanism of shallow gas accumulations in the SW Barents Sea 

      Kjerkreit, Kristian (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 ...
    • Oscillations:Linear theory and applications in AFM 

      Olukan, Tuza Adeyemi; Santos, Sergio; Elsherbiny, Lamia; Chiesa, Matteo (Research report; Forskningsrapport, 2022)
      The theory of oscillations can be studied from a mathematical point of view in terms of differential equations. The differential equation is written and then the solution or solutions worked out and mathematically analysed. Provided physical, economic, social, or other phenomena can be modelled in terms of equivalent differential equations, the solutions and results are applicable to all phenomena ...
    • Outlier classification using autoencoders: Application for fluctuation driven flows in fusion plasmas 

      Kube, Ralph; Bianchi, Filippo Maria; LaBombard, Brian; Brunner, Dan (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-16)
      Understanding the statistics of fluctuation driven flows in the boundary layer of magnetically confined plasmas is desired to accurately model the lifetime of the vacuum vessel components. Mirror Langmuir probes (MLPs) are a novel diagnostic that uniquely allow us to sample the plasma parameters on a time scale shorter than the characteristic time scale of their fluctuations. Sudden large-amplitude ...
    • Outlier classification using Autoencoders: applications for fluctuation driven flows in fusion plasmas 

      Kube, Ralph; Bianchi, Filippo Maria; LaBombard, Brian; Brunner, Dan (Conference object; Konferansebidrag, 2018)
    • Overview: Recent advances in the understanding of the northern Eurasian environments and of the urban air quality in China-a Pan-Eurasian Experiment (PEEX) programme perspective 

      Lappalainen, Hanna K.; Petäjä, Tuukka; Vihma, Timo Pekka; Räisänen, Jouni; Baklanov, Alexander; Chalov, Sergey; Esau, Igor; Ezhova, Ekaterina; Leppäranta, Matti; Pozdnyakov, Dmitry; Pumpanen, Jukka; Andreae, Meinrat O.; Arshinov, Mikhail; Asmi, Eija; Bai, Jianhui; Bashmachnikov, Igor; Belan, Boris; Bianchi, Federico; Biskaborn, Boris; Boy, Michael; Bäck, Jaana; Cheng, Bin; Chubarova, Natalia; Duplissy, Jonathan; Dyukarev, Egor; Eleftheriadis, Konstantinos; Forsius, Martin; Heimann, Martin; Juhola, Sirkku; Konovalov, Vladimir; Konovalov, Igor; Konstantinov, Pavel; Köster, Kajar; Lapshina, Elena; Lintunen, Anna; Mahura, Alexander; Makkonen, Risto; Malkhazova, Svetlana; Mammarella, Ivan; Mammola, Stefano; Mazon, Stephany Buenrostro; Meinander, Outi; Mikhailov, Eugene; Miles, Victoria; Myslenkov, Stanislav; Orlov, Dmitry; Paris, Jean-Daniel; Pirazzini, Roberta; Popovicheva, Olga; Pulliainen, Jouni; Rautiainen, Kimmo; Sachs, Torsten; Shevchenko, Vladimir; Skorokhod, Andrey; Stohl, Andreas; Suhonen, Elli; Thomson, Erik S.; Tsidilina, Marina; Tynkkynen, Veli-Pekka; Uotila, Petteri; Virkkula, Aki; Voropay, Nadezhda; Wolf, Tobias; Yasunaka, Sayaka; Zhang, Jiahua; Qiu, Yubao; Ding, Aijun; Guo, Huadong; Bondur, Valery; Kasimov, Nikolay; Zilitinkevich, Sergej; Kerminen, Veli-Matti; Kulmala, Markku (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-06)
      The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topics of the research agenda. These two geographical ...