Recent additions

  • 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 ...
  • IR THERMOGRAPHY in Multiphysics Applications 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2018)
    It is seen that Infrared (IR) thermography is becoming one of the very popular and effective methods in the industry as well as research and development sectors. IR thermography being a remote non-contact/non-destructive means of testing is perfectly suitable for tests in extreme environments. In addition, it is fast, reliable and detailed. Due to the advantages offered by IR thermography, it is ...
  • Is Thorium a Viable Nuclear Fuel? [poster] 

    Khawaja, Hassan; Moatamedi, Mojtaba; Tehrani, Ali (Conference object; Konferansebidrag, 2018)
    Thorium was discovered in 1829 by the Norwegian mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder. Thorium is more abundant in nature than Uranium. It is fertile rather than fissile, and can only be used as a fuel in conjunction with a fissile material such as recycled plutonium. Thorium fuels can breed ...
  • Infrared Thermography (IRT) of Conjugate Heat Transfer (CHT) Problem and Comparison with Multiphysics Model 

    Khawaja, Hassan; Moatamedi, Mojtaba; Alzahabi, Basem (Conference object; Konferansebidrag, 2018)
    This work presents a problem undergoing conjugate heat transfer (CHT). Conjugate heat transfer problems are common is domestic heating/cooling, industrial heat exchangers, cooling of electronics (e.g. PC fans). It is to be noted that in conjugate heat transfer problems, the convection part of the heat transfer is dominated. In the given study, a hypothetical case is built where a heat source (a ...
  • Sound waves in fluidized bed using CFD–DEM simulations 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2018)
    The seminar is about modelling sound waves in a fluidized bed using CFD–DEM numerical simulations. The presented case includes the application of appropriate initial and boundary conditions to reproduce bed phenomena and the effect of varying the bed height. The results of the simulations matched those from the literature. The pressure and particle velocity profiles obtained feature oscillatory ...
  • Detection, Identification and Size distribution of micro-plastic particles 

    Varughese, Bindu Sara; Edvardsen, Kåre (Conference object; Konferansebidrag, 2017)
    Pollution by micro-plastic in ecosystems is one of the major problems we are facing now, especially in marine environment. Many studies are going on the detection of different micro substances that pollute our environment. Micro-plastics are among the more frequent pollutants of the sort in aquatic ecosystems. There have been some studies earlier on methodologies to detect and identify micro-plastic ...
  • Solution of Pure Scattering Radiation Transport Equation (RTE) using Finite Difference Method (FDM) (poster) 

    Khawaja, Hassan; Moatamedi, Mojtaba (Conference object; Konferansebidrag, 2018)
    Radiative transfer is the physical phenomenon of energy transfer in the form of electromagnetic radiation. The propagation of radiation through a medium is affected by absorption, emission, and scattering. Radiative Transfer Equation (RTE) have been applied in a many subjects including atmospheric science, astrophysics, nuclear, optics, remote sensing, etc. Analytic solutions for RTE exist for simple ...
  • 25-years Svalbard data record reveals change in long-range transport of sulphur agents to the warming Arctic 

    Dekhtyareva, Alena (Conference object, 2019)
    Current study investigates the 25-years seasonal trend in the concentration of SO2and non-sea salt SO42-and compares observed changes with the evolution in emission of sulphur agents in primary source regions of anthropogenic aerosols and alteration in characteristics of air masses transporting pollutants to Svalbard.
  • Cold Technology Applications of Infrared Thermography (IRT) 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2019)
  • Multiphysics Study of Infrared Thermography (IRT) Applications 

    Andleeb, Zahra; Malik, Sohail; Hussain, Gulam; Khawaja, Hassan; Roemer, Jakub; Boiger, Gernot; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-19)
    The paper reviews thermographic and vibrothermography applications such as cold climate operations, determine the temperature profile of steel samples under tensile testing and perform composites Non-Destructive Testing (NDT). This review paper discusses studies, where IR thermography has been used effectively in research and development projects at the UiT The Arctic University of Norway and AGH ...

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