Now showing items 21-40 of 4765

    • NordVulk 1974-2024 

      Sturkell, Erik; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2024)
      Nordisk Vulkanologisk Institut, senare känt som Nordisk Vulkanologisk Center (NordVulk) på Island fyller 50 år 2024. Tyvärr sammanfaller jubileet med att NordVulk upphör i sin nuvarande form och en lång och framgångsrik era med nordisk vulkanologisk forskning på Island tar slut. Här berättar vi lite om NordVulks historia och bifogar några korta anekdoter från livet där.
    • Glacial-interglacial sedimentation control on gas seepage exemplified by Vestnesa Ridge off NW Svalbard margin 

      Rasmussen, Tine Lander; Nielsen, Tove (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-08)
      Vestnesa Ridge is built-up of thick contourites mainly deposited during the last ∼5 million years. Methane leaks from deep gas reservoirs creating pockmarks on its crest, and which have been the focus of numerous studies. Sedimentation patterns in relation to the pronounced changes in oceanography and climate of the last glacial-interglacial cycles and its possible impact of seepage of gas have ...
    • New cold seep sites on the continental slope southwest to Svalbard 

      Bellec, Valerie Karin; Chand, Shyam; Knies, Jochen Manfred; Bjarnadóttir, Lilja Rún; Lepland, Aivo; Sen, Arunima; Thorsnes, Terje (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-09)
      We discovered seafloor features such as bacterial mats and carbonate crusts typical for active methane seeps on the continental slope southwest of Svalbard. These features are associated with two main northwest-southeast trending morphological structures that are oriented parallel to the regional continental slope. Both structures occur at c. 800 m water depth, at the boundary between the Storfjorden ...
    • Beyond the Oberbeck-Boussinesq and long wavelength approximation 

      Held, Markus; Wiesenberger, Matthias (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-22)
      We present the first simulations of a reduced magnetized plasma model that incorporates both arbitrary wavelength polarization and non-Oberbeck–Boussinesq effects. Significant influence of these two effects on the density, electric potential and <i><b>E</i></b> × <i><b>B</i></b> vorticity and non-linear dynamics of interchange blobs are reported. Arbitrary wavelength polarization implicates so-called ...
    • DFT and electrochemical study on some iron(III) complexes with 2-hydroxybenzophenones 

      Chiyindiko, Emmie; Langner, Ernst H.G.; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-17)
      The synthesis, identification and electrochemical behaviour iron(III) complexes containing different 2-hydroxybenzophenone ligands are reported. The first reduction of the tris(2-hydroxybenzophenone)iron(III) complexes follow the same trend as that of the free, uncoordinated ligands and bis(2-hydroxybenzophenone)copper(II) complexes. The first reduction of the iron(III) complexes occur at a potential ...
    • Quantifying Intramolecular Basis Set Superposition Errors 

      Pitteloud, Quentin Grégoire; Wind, Peter Ariaan; Jensen, Stig Rune; Frediani, Luca; Jensen, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-18)
      We show that medium-sized Gaussian basis sets lead to significant intramolecular basis set superposition errors at Hartree–Fock and density functional levels of theory, with artificial stabilization of compact over extended conformations for a 186 atom deca-peptide. Errors of ∼80 and ∼10 kJ/mol are observed, with polarized double zeta and polarized triple zeta quality basis sets, respectively. Two ...
    • Analysis of time series of polarimetric sea ice signatures observed in fast ice it the Belgica Bank area 

      Eltoft, Torbjørn; Johansson, Malin; Lohse, Johannes; Ferro-Famil, Laurent (Journal article; Tidsskriftartikkel, 2023-10-20)
      The CIRFA-Cruise 2022 with <i>RV Kronprins Haakon</i> to the north-eastern coast of Greenland in the period April 22nd to May 9th 2022 was organised to perform measurements and make observations which allow for validation of sea ice remote sensing information and forecast products resulting from work in the Centre for Integrated Remote Sensing and Forecasting for Arctic Operations(CIRFA), a Centre ...
    • Characterizing vegetation and return periods in avalanche paths using lidar and aerial imagery 

      Peitzsch, Erich H.; Martin-Mikle, Chelsea; Hendrikx, Jordy; Birkeland, Karl; Fagre, Daniel (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-14)
      Snow avalanches are a hazard and ecological disturbance across mountain landscapes worldwide. Understanding how avalanche frequency affects forests and vegetation improves infrastructure planning, risk management, and avalanche forecasting. We implemented a novel approach using lidar, aerial imagery, and a random forest model to classify imagery-observed vegetation within avalanche paths in southern ...
    • Influence of a rigid backstop on the flow pattern during thrusting of the supracrustal Balsfjord Series of the North Norwegian Caledonides 

      Höpfl, Stephan Maximilian; Konopásek, Jiří; Sláma, Jiří (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-17)
      The Caledonian evolution of the low–medium grade Balsfjord Series (Troms, Northern Norway) is characterized by four sets of deformation structures that developed progressively during burial and exhumation from underneath the high-grade Nakkedal and Tromsø nappe complexes. The Balsfjord Series commonly displays top-to-the SSE–SE directed movement during the development of the main metamorphic fabric ...
    • Persistence of Holocene ice cap in northeast Svalbard aided by glacio-isostatic rebound 

      Farnsworth, Wesley Randall; Ingólfsson, Ólafur; Brynjólfsson, Skafti; Allaart, Lis; Kjellman, Sofia Elisabeth; Kjær, Kurt H.; Larsen, Nicolaj K.; Macias-Fauria, Marc; Siggaard-Andersen, Marie-Louise; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-29)
      The deglaciation of the Svalbard-Barents Sea Ice Sheet was driven by relative sea-level rise, the incursion of North Atlantic waters around Spitsbergen, and increasing summer insolation. However, ice retreat was inter rupted by asynchronous re-advances that occurred into high relative seas, during a period associated with warm regional waters and elevated summer temperatures. Better understanding ...
    • Distinguishing Mineral Oil Slicks from Low Wind Areas using Rapid Repeat Synthetic Aperture Radar Imagery 

      Quigley, Cornelius Patrick; Johansson, Anna Malin Kristin; Jones, Cathleen Elaine; Holt, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-18)
      A method for differentiating marine oil slicks from radar-dark, low wind areas in open water using rapid repeat SAR imagery is reported. The study uses data acquired by the airborne UAVSAR L-band SAR instrument, imaging the Coal Oil Point seep field near Santa Barbara, California. Time-series of images from three different days are analyzed, all containing both verified oil slicks and low wind zones. ...
    • Real-Time Change Detection with Convolutional Density Approximation 

      Ha, Synh Viet-Uyen; Nguyen, Tien Cuong; Phan, Hung Ngoc; Ha, Hoai Phuong (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-02)
      Background Subtraction (BgS) is a widely researched technique to develop online Change Detection algorithms for static video cameras. Many BgS methods have employed the unsupervised, adaptive approach of Gaussian Mixture Model (GMM) to produce decent backgrounds, but they lack proper consideration of scene semantics to produce better foregrounds. On the other hand, with considerable computational ...
    • On uniqueness of submaximally symmetric parabolic geometries 

      The, Dennis (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-24)
      Among (regular, normal) parabolic geometries of type (<i>G,P</i>), there is a locally unique maximally symmetric structure and it has symmetry dimension dim(<i>G</i>). The symmetry gap problem concerns the determination of the next realizable (submaximal) symmetry dimension. When <i>G</i> is a complex or split-real simple Lie group of rank at least three or when (<i>G,P</i>) = (<i>G<sub>2</sub></i>, ...
    • Preservice and inservice teachers’ views on digital tools for diverse learners in mathematics education 

      Meaney, Tamsin Jillian; Huru, Hilja Lisa; Kvivesen, Mona (Journal article; Tidsskriftartikkel; Peer reviewed, 2023)
      Although teachers are expected to use digital tools in their mathematics teaching in many countries, little is known about preservice and inservice teachers’ digital competence, especially in relationship to specific groups of school students. Results from a survey of 394 preservice teachers and 61 inservice teachers, at three Norwegian institutions, provide information on how they considered different ...
    • Investigation and analysis of the ‘cold’ sensation relation with respect to associated parameters: wind velocity, ambient temperature, humidity, and irradiance 

      Nadem Leyli, Amir (Master thesis; Mastergradsoppgave, 2019-07-15)
      The Arctic is considered as one of the regions in the world with various resources including oil and gas. Many industries are moving further up north to this area or new industries are being established. Technologies and industries in the Arctic have many challenges regarding the harsh cold climate. One of the main challenges which is of importance in this thesis is human exposure to the cold that ...
    • Assessing resilience in mechanical systems: an industrial perspective 

      Nouri Qarahassanlou, Ali; Ali, Rahimazar; Dina, Khanzadeh (Journal article; Tidsskriftartikkel; Peer reviewed, 2024)
      Purpose - Resilience as a novel concept has attracted the most attention in the management of engineering systems. The main goal of engineering systems is production assurance and increasing customer satisfaction which depends on the suitable performance of mechanical equipment. “A resilient system is defined as a system that is resistant to disruption and failures and can recover itself and returns ...
    • Assessing resilience in mechanical systems: an industrial perspective 

      Nouri Qarahassanlou, Ali; Rahimazar, Ali; Khanzadeh, Dina (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-12)
      Purpose - Resilience as a novel concept has attracted the most attention in the management of engineering systems. The main goal of engineering systems is production assurance and increasing customer satisfaction which depends on the suitable performance of mechanical equipment. “A resilient system is defined as a system that is resistant to disruption and failures and can recover itself and returns ...
    • Correlation between Wettability and Dissolution of Calcite in Ion-Free Water 

      AlMahri, Mariam; Lu, Jin-You; Chen, Shih-Wen; Olukan, Tuza Adeyemi; Yang, Thomas Chung-Kuang; Alhassan, Saeed; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-13)
      Calcite, a prevalent mineral in the earth’s crust, plays a pivotal role in various geological and industrial processes, including carbon sequestration, water treatment, and enhanced oil recovery. Understanding how wettability (a crucial surface property influenced by the interaction between calcite and surrounding fluids) affects calcite’s dissolution is essential for optimizing these processes. We ...
    • Tracing Subducted Carbonates in Earth's Mantle Using Zinc and Molybdenum Isotopes 

      Wang, Jian; Tang, Gong-Jian; Tappe, Sebastian; Li, Jie; Zou, Zongqi; Wang, Qiang; Su, Yu-Ping; Zheng, Jian-Ping (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-23)
      Although carbonates are the primary form of carbon subducted into the mantle, their fate during recycling is debated. Here we report the first coupled high-precision Zn and Mo isotope data for Cenozoic intraplate basalts from western China. The exceptionally high δ<sup>66</sup>Zn values (+0.39 to +0.50‰) of these lavas require involvement of recycled carbonates in the mantle source. Variable ...
    • Efficient palladium-catalyzed electrocarboxylation enables late-stage carbon isotope labelling 

      Batista, Gabriel M. F.; Ebenbauer, Ruth; Day, Craig S.; Bergare, Jonas; Neumann, Karoline; Hopmann, Kathrin Helen; Elmore, Charles; Rosas-Hernandez, Alonso; Skrydstrup, Troels (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-22)
      Carbon isotope labelling of bioactive molecules is essential for accessing the pharmacokinetic and pharmacodynamic properties of new drug entities. Aryl carboxylic acids represent an important class of structural motifs ubiquitous in pharmaceutically active molecules and are ideal targets for the installation of a radioactive tag employing isotopically labelled CO<sub>2</sub>. However, direct isotope ...