Recent additions

  • Estimating the impact of indoor relative humidity on SARS-CoV-2 airborne transmission risk using a new modification of the Wells-Riley model 

    Aganovic, Amar; Bi, Yang; Cao, Guangyu; Drangsholt, Finn; Kurnitski, Jarek; Wargocki, Pawel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-23)
    A novel modified version of the Wells-Riley model was used to estimate the impact of relative humidity (RH) on the removal of respiratory droplets containing the SARS-CoV-2 virus by deposition through gravitational settling and its inactivation by biological decay; the effect of RH on susceptibility to SARS-CoV-2 was not considered. These effects were compared with the removal achieved by increased ...
  • Optimization of a mixed refrigerant based H2 liquefaction pre-cooling process and estimate of liquefaction performance with varying ambient temperature 

    Jackson, Steven; Brodal, Eivind (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-24)
    Hydrogen used as an energy carrier can provide an important route to the decarbonization of energy supplies, but realizing this opportunity will require both significantly increased production and transportation capacity. One route to increased transportation capacity is the shipping of liquid hydrogen, but this requires an energy-intensive liquefaction step. Recent study work has shown that the ...
  • Atmospheric Contamination of Coastal Cities by the Exhaust Emissions of Docked Marine Vessels: The Case of Tromsø 

    Zubiaga, Asier; Madsen, Synne; Khawaja, Hassan; Boiger, Gernot (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-03)
    Docked ships are a source of contamination for the city while they keep their engine working. Plume emissions from large boats can carry a number of pollutants to nearby cities causing a detrimental effect on the life quality and health of local citizens and ecosystems. A computational fluid dynamics model of the harbour area of Tromsø has been built in order to model the deposition of CO2 gas emitted ...
  • Ventilation design conditions associated with airborne bacteria levels within the wound area during surgical procedures: a systematic review 

    Aganovic, Amar; Cao, Guangyu; Fečer, Tomáš; Ljungqvist, Bengt L.; Lytsy, Birgitta; Radtke, Andreas; Reinmüller, Berit; Traversari, Roberto A.A.L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-26)
    Without confirmation of the ventilation design conditions (typology and airflow rate), the common practice of identifying unidirectional airflow (UDAF) systems as equivalent to ultra-clean air ventilation systems may be misleading, but also any claims about the ineffectiveness of UDAF systems should be doubted. The aim of this review was to assess and compare ventilation system design conditions for ...
  • Havforskningsinsituttets rådgivning for menneskeskapt støy i havet - Kunnskapsgrunnlag, vurderinger og råd for 2021 

    Sivle, Lise Doksæter; Forland, Tonje Nesse; de Jong, Karen; Kutti, Tina; Zhang, Guosong; Wehde, Henning; Grimsbø, Endre (Research report; Forskningsrapport, 2021-01-11)
    Havforskningsinstituttet gir råd for alle operasjoner til havs som involverer bruk av lydkilder som kan påvirke marine økosystemer. Dette inkluderer vitenskapelige undersøkelser, undersjøiske sprenginger, operasjoner knyttet til utbygging til havs, og seismiske og elektromagnetiske undersøkelser i forbindelse med petroleumsvirksomhet. Det er nå også inkludert råd i forbindelse med utbygging av ...
  • Strain Wave Analysis in Carbon-Fiber-Reinforced Composites subjected to Drop Weight Impact Test using ANSYS® 

    Andleeb, Zahra; Malik, Sohail; Khawaja, Hassan; Antonsen, Ståle; Hassan, Taimur; Hussain, Ghulam; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-11)
    Composite materials are becoming more popular in technological applications due to the significant weight savings and strength these materials offer compared to metallic materials. In many of these practical situations, the structures suffer from drop impact loads. Materials and structures significantly change their behavior when submitted to impact loading conditions as compared to quasi-static ...
  • Numerical conservative solutions of the Hunter–-Saxton equation 

    Grunert, Katrin; Nordli, Anders Samuelsen; Solem, Susanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-21)
    In the article a convergent numerical method for conservative solutions of the Hunter–Saxton equation is derived. The method is based on piecewise linear projections, followed by evolution along characteristics where the time step is chosen in order to prevent wave breaking. Convergence is obtained when the time step is proportional to the square root of the spatial step size, which is a milder ...
  • Atmospheric Contamination of Coastal Cities by the Exhaust Emissions of Docked Marine Vessels: the case of Tromsø 

    Zubiaga, Asier; Madsen, Synne; Khawaja, Hassan; Boiger, Gernot (Journal article; Tidsskriftartikkel, 2021-08-04)
    Docked ships are a source of contamination for the city while they keep their engine working. Plumes emissions from large boats can carry a number of pollutants to the nearby cities causing a detrimental effect on the life quality and health of local citizens and ecosystems. A computational fluid dynamics model of the harbour area of Tromsø has been built in order to model the deposition of CO2 gas ...
  • Modeling of Pressure and Temperature Profiles for the Flow of CO2 through a Restriction 

    Leyli, Amir Nadem; Jackson, Steven; Khawaja, Hassan; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-19)
    CO<sub>2</sub> emissions due to massive industrialization have led to several environmental issues. Carbon Capture and Storage (CCS) is one of the most important technologies that can be used to reduce anthropogenic CO<sub>2</sub> emissions worldwide. CCS projects mainly involve three processes: carbon capture, transportation, and storage. In the transportation process, the modeling of the flow in ...
  • Recognizing Potential of LiDAR for Comprehensive Measurement of Sea Spray Flux for Improving the Prediction of Marine Icing in Cold Conditions - A Review 

    Dhar, Sushmit; Khawaja, Hassan (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-06)
    Marine icing phenomenon depends on multiple variables like vessel characteristics and uncertain factors like environmental parameters, developing an accurate model for its forecasting, evaluation, and estimation is very challenging. Commonly, most severe ice accretion is caused due to sea spray. The past attempts to measure impinging sea spray flux were carried out on specific parts of the spray ...
  • Path planning and collision avoidance for autonomous surface vehicles I: a review 

    Vagale, Anete; Oucheikh, Rachid; Bye, Robin Trulssen; Osen, Ottar Laurits; Fossen, Thor I. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-29)
    Autonomous surface vehicles are gaining increasing attention worldwide due to the potential benefits of improving safety and efficiency. This has raised the interest in developing methods for path planning that can reduce the risk of collisions, groundings, and stranding accidents at sea, as well as costs and time expenditure. In this paper, we review guidance, and more specifically, path planning ...
  • Path planning and collision avoidance for autonomous surface vehicles II: a comparative study of algorithms 

    Vagale, Anete; Bye, Robin Trulssen; Oucheikh, Rachid; Osen, Ottar; Fossen, Thor I. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-06)
    Artificial intelligence is an enabling technology for autonomous surface vehicles, with methods such as evolutionary algorithms, artificial potential fields, fast marching methods, and many others becoming increasingly popular for solving problems such as path planning and collision avoidance. However, there currently is no unified way to evaluate the performance of different algorithms, for example ...
  • Frequency Support of Fast-Multi-Energy Storage Systems in Low Rotational Inertia Scenarios 

    Ersdal, Anne Mai; Acosta Montalvo, Martha Nohemi; Gonzalez-Longatt, Francisco; Torres, José Luis Rueda; Palenski, Peter (Peer reviewed; Chapter, 2020-11-10)
    Modern power systems are increasing the connection of power electronic converters (PECs), and new inertia-less technologies displace the synchronous generation units. Therefore, the total rotational system inertia is reduced, creating new problems related to the system frequency control and stability. Several mechanisms to enable the PECs with frequency sensible control loops have been proposed in ...
  • Sensitivity Analysis and Case Studies for CO2 Transportation Energy Consumption 

    Jackson, Steven (Journal article; Tidsskriftartikkel; Peer reviewed, 2020)
    The transportation of CO2 is important to all Carbon Capture and Storage (CCS) projects. Both the infrastructure costs – compressors, pipelines, tanker ships, etc. – and the energy consumed in the compression or liquefaction of CO2 are significant. Understanding how the size, capacity and energy consumption of transportation alternatives varies between projects is therefore important. Modelling ...
  • Optimization study of heat pumps using refrigerant blends – Ejector versus expansion valve systems 

    Brodal, Eivind; Eiksund, Oddmar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-19)
    This article investigates tap water heating systems to highlight an ongoing debate. Some report that CO2-based transcritical heat pumps with an ejector have the best coefficient of performance (COP), while others report that blend-based refrigerant systems (without an ejector) are better. In the literature, however, these systems are only compared with conventional heat pump designs, and not against ...
  • Conjugate Heat Transfer Model Based on SIMPLE and Coupled Energy and Heat Equations 

    Leyli, Amir Nadem; Andleeb, Zahra; Khawaja, Hassan; Messahel, Ramzi; Kanna, Rajesh; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-28)
    In this study, a numerical weak coupling strategy for the modeling of a conjugate heat transfer phenomenon is considered. Where the incompressible Navier-Stokes equations are solved using the Semi-Implicit Method for Pressure Linked Equations (SIMPLE) as a first step, and then the heat conduction equation for solid is solved in a second step considering the convective velocity field resulting from ...
  • Influence of seasonal mesoscale and microscale meteorological conditions in Svalbard on results of monitoring of long-range transported pollution [poster] 

    Dekhtyareva, Alena; Holmén, Kim; Maturilli, Marion; Hermansen, Ove; Graversen, Rune (Conference object; Konferansebidrag, 2018)
    The Zeppelin Observatory is an atmospheric monitoring station located on the northwest coast of Spitzbergen island, in the Svalbard archipelago. The station provides background air composition, meteorological and climatological data for numerous research projects. The observatory is located on a mountain ridge in a region with complex topography that affects local atmospheric circulation ...
  • Fluid-Structure Interaction (FSI) of Aquaculture Net Cages [poster} 

    Myrli, Odd Einar; Khawaja, Hassan (Conference object; Konferansebidrag, 2018)
    The number of good sites in less exposed locations for aquaculture farming is limited. Trends are now that the fish cages are increasing in both width and depth as well as more weather-exposed locations, are taken into use. As the net cages continue to increase in size, so does the material costs. The design of the sea cages should be modified for safe and reliable use in remote offshore locations. ...
  • Multiphysics Analysis of Contact Pressure Profile of Airless tires as compared to Conventional Tires 

    Ludvigsen, Søndre; Andleeb, Zahra; Khawaja, Hassan; Moatamedi, Mojtaba; Alzahabi, Basem (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-15)
    The harsh climate of the Arctic has always posed significant challenges to car drivers. The severe loss in traction due to snow and icing on the roads has led to an increased risk of collisions. The purpose of this work is to replace the conventional air-filled tire with a non-pneumatic tire to improve the grip in the Arctic conditions. The grip obtained for tires is determined by the weight of the ...
  • CFD modelling of pollutant transport 

    Madsen, Synne; Khawaja, Hassan (Conference object; Konferansebidrag, 2018)
    With the increase of the human activities in the Arctic, including land and sea, is resulting in higher release of pollutants to the environment. These pollutants can be categorised as gases released in the air such as carbon dioxide, sulphur dioxide, NOx, etc., and waste released in seas such as chemical toxins, microplastic, etc. This work presents a computational fluid dynamics (CFD) study ...

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