Browsing USN Open Archive by Author "Bjerketvedt, Dag"

Now showing items 1-20 of 43

    • An experimental investigation of rapid boiling of CO2 

      Tøsse, Sindre; Vågsæther, Knut; Bjerketvedt, Dag (Journal article; Peer reviewed, 2014-09-27)
      Storage of pressurized liquified gases is a growing safety concern in many industries. Knowledge of the thermodynamics and kinetics involved in the rapid depressurization and evaporation of such substances is key to the ...

    • An experimental study of temperatures in cloud from release of flashing liquid CO2 in 3m long channel. 

      Adhikari, Amrit; Gaathaug, André Vagner; Bjerketvedt, Dag; Vågsæther, Knut (Journal article; Peer reviewed, 2014)
      Flashing of the liquid CO2 is an accidental hazards that may occurs in many industrial sector such as, process industries, carbon capture and storage projects, crude oil extraction process etc. Sometimes the accidental ...

    • Analysis of DNA polymorphism in wild populations of herb-Paris (Paris quadrifolia L., Trilliaceae) from Lithuania and Norway. 

      Jogaitė, Vaida; Lazutka, Juozas R.; Naujalis, Jonas; Stapulionyte, Asta; Odland, Arvid; Bjerketvedt, Dag (Journal article; Peer reviewed, 2006)
      Analysis of random amplified polymorphic DNA (RAPD) was used to determine genetic diversity within the populations of herb-Paris plant from Lithuania and Norway. RAPD analyses have shown 21.9 ± 5.2% of polymorphic loci in ...

    • Are trampling effects by wild tundra reindeer understudied? 

      Heggenes, Jan; Odland, Arvid; Bjerketvedt, Dag (Journal article; Peer reviewed, 2018)
      Grazing and trampling by the wide-ranging wild tundra reindeer may have major top down landscape effects by causing vegetation changes. Grazing, as the collective effect of eating, trampling, defecation, and urination, has ...

    • Blitzfotografering av bevegelige objekter gjennom mikroskop 

      Bjerketvedt, Dag (Journal article, 1981)
      Ordinary microscopes can be adapted to fully automatic photomicroscopes for use with flash. An automatic small film camera with an autodynamic flash and extra equipment for microphotography is necessary. The camera's ...

    • Boiling liquid expanding vapour explosion in CO2 small scale experiments 

      Bjerketvedt, Dag; Egeberg, Kjersti; Ke, Wei; Gaathaug, André Vagner; Vågsæther, Knut; Nilsen, Sandra Hennie (Journal article; Peer reviewed, 2011-04)
      Carbon capture and storage systems require handling large volumes of high pressure CO2. Having thorough knowledge of the related hazards is essential, as is knowing how to prevent, detect, control and mitigate accidents. ...

    • CFD-Simulations of inhomogeneous H2-air explosions 

      Aghaabbasi, Omid (Master thesis, 2021)
      Since demands for energy resources increase globally in recent years due to growth of application consumption, finding alternative resources for traditional fossil fuels raises. These current fuels are diminishing continuously ...

    • Detonation propagation in stratified reactant layers 

      Gaathaug, André Vagner; Bjerketvedt, Dag; Lundberg, Joachim; Vågsæther, Knut (Journal article; Peer reviewed, 2017)
      A numerical investigation of detonation propagation in stratified reactant layers is presented in this paper. It is baesed on the reactive Euler equations using a two step chemical kinetics approach. The numerical simulations ...

    • Effect of alternative fuel properties on NOx reduction 

      Axelsen, Ernst Petter; Tokheim, Lars-André; Bjerketvedt, Dag (Conference report, 2002)
      Today we see a substantial increase in the use of alternative fuels in the cement industry. The prospect of reduction in fuel costs and the environmental benefits of waste to energy conversion are the driving forces. For ...

    • Energy recovery from wastes : experience with solid alternative fuels combustion in a precalciner cement kiln 

      Tokheim, Lars-André; Gautestad, Tor; Axelsen, Ernst Petter; Bjerketvedt, Dag (Conference report, 2001)
      Today virtually all cement clinker burning processes take place in rotary kilns. A mixture of calcareous and argilaceous materials is heated to a temperature of about 1450 °C. In this process decarbonation followed by ...

    • Estimation of lichen biomass with emphasis on reindeer winter pastures at Hardangervidda, S Norway 

      Odland, Arvid; Sandvik, Sylvi M.; Bjerketvedt, Dag; Myrvold, Linn L. (Journal article; Peer reviewed, 2014)
      Quantification of lichen abundance is important for management of reindeer populations. We measured dry lichen biomass in 876 micro plots (16.5 cm - 16.5 cm) systematically sampled within 219 vegetation plots (2 m - 2 m) ...

    • Evaporation characteristics during decompression of liquified CO2 from a conical-shaped vessel 

      Ibrahim, Osama Kabbashi M.; Hansen, Per Morten; Bjerketvedt, Dag; Vågsæther, Knut (Peer reviewed; Journal article, 2021)
      Safe transport of pressurized CO2 requires a profound knowledge of the processes' effect during the phase transition on catastrophic failure of a tanker filled with liquid CO2. This study presents experimental results and ...

    • Experimental investigation and simulation of ignition of fuel-air clouds with fuel mixtures of hydrogen and hydrogen-carrying fuels 

      Tkachenko, Anna (Master thesis, 2021)
      Hydrogen is playing an increasingly important role as the world moves to a low-carbon energy system, but combustion properties of this gas are very different from other hydrogen-carrying fuels that can lead to difficulties ...

    • Experimental Study of Gas Explosions in Hydrogen Sulfide-Natural Gas-Air Mixtures 

      Gaathaug, André Vagner; Bjerketvedt, Dag; Vågsæther, Knut; Nilsen, Sandra Hennie (Journal article; Peer reviewed, 2014-08-21)
      An experimental study of turbulent combustion of hydrogen sulfide (H2S) and natural gas was performed to provide reference data for verification of CFD codes and direct comparison. Hydrogen sulfide is present in most crude ...

    • Experimental study of primary atomization characteristics of sonic air-assist atomizers 

      Sikka, Raghav; Vågsæther, Knut; Bjerketvedt, Dag; Lundberg, Joachim (Journal article; Peer reviewed, 2021)
      The present study compares two twin-fluid atomizer concepts based on the airflow (shock waves) pattern obtained through shadowgraph imaging for atomization of water with a low air/water pressure supply. The research work ...

    • Experimental Study of the Initial Flame Propagation of Premixed H2-air Explosion in a Channel 

      Rai, Kanchan; Bjerketvedt, Dag; Sommersel, Ole Kristian (Conference object; Peer reviewed, 2009-07)
      This paper presents results from experiments on flame propagation in inhomogeneous and homogeneous hydrogen-air mixtures at 1 atm in a channel. The objective of the present work is to study the ininitial phase of the flame ...

    • Experiments with flame propagation in a channel with one obstacle and premixed H2-air 

      Gaathaug, André Vagner; Bjerketvedt, Dag; Vågsæther, Knut (Conference object; Peer reviewed, 2009-07)
      This abstract presents experimental results of flame propagation in a square channel with a single obstacle. The background for the experimental study was to investigate how a flame propagated when and after the flame ...

    • Explosion characteristics for Li-ion battery electrolytes at elevated temperatures 

      Henriksen, Mathias; Vågsæther, Knut; Lundberg, Joachim; Forseth, Sissel; Bjerketvedt, Dag (Peer reviewed; Journal article, 2019)
      Li-ion batteries are used in electronic devices and electric cars, yet they create safety concerns due to the possibility of the release of combustible materials. The electrolyte, one of the main components in a Li-ion ...

    • Herbivore grazing—or trampling? Trampling effects by a large ungulate in cold high- latitude ecosystems 

      Heggenes, Jan; Odland, Arvid; Chevalier, Tomas; Ahlberg, Jörgen; Berg, Amanda; Larsson, Håkan; Bjerketvedt, Dag (Journal article; Peer reviewed, 2017)
      Mammalian herbivores have important top-down effects on ecological processes and landscapes by generating vegetation changes through grazing and trampling. For free-ranging herbivores on large landscapes, trampling is an ...

    • Kartlegging av snøbare rabber og vinterbeite i Brattefjell- Vindeggen 

      Hjeltnes, Arne; Bjerketvedt, Dag; Odland, Arvid; Tien Bui, Dieu; Heggenes, Jan (Skriftserien fra Høgskolen i Sørøst-Norge;17, Research report, 2018-01-11)
      Her gis en underveis-rapport om arbeidet med å utvikle en metode for å estimere tilgjengelige vinterbeiteressurser for villrein, i hovedsak basert på fjernanalyse (satellittbilder og ortofoto), supplert med feltregistreringer ...