Recent additions

  • Determining Thermal Properties of Polyurethane by Solving the Heat Equation and IR Imaging 

    Norum, Hans-Kristian; Andleeb, Zahra; Khawaja, Hassan; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-27)
    All materials have different and unique thermal properties that determine how the temperature changes when a material is subjected to a temperature difference. This study was intended to investigate the thermal properties of a polymer called Polyurethane, focusing on anti-seepage and anti-abrasion polyurethane. The thermal conductivity and heat transfer coefficient of cold polyurethane specimens ...
  • Dihedral Group D4—A New Feature Extraction Algorithm 

    Sharma, Puneet (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-04)
    In this paper, we propose a new feature descriptor for images that is based on the dihedral group D<sub>4</sub>, the symmetry group of the square. The group action of the D<sub>4</sub> elements on a square image region is used to create a vector space that forms the basis for the feature vector. For the evaluation, we employed the Error-Correcting Output Coding (ECOC) algorithm and tested our model ...
  • Multiphysics based Modal and Harmonic Analysis of Axial Turbines 

    Khawaja, Hassan; Andleeb, Zahra; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-15)
    The presented work discusses the vibration behavior of an axial turbine, analyzed using the finite element method (FEM) using commercial software ANSYS®. The turbine was modeled as a 2-D plate type of structure discretized with 4-noded shell 63 elements to save computational time. Constraints were applied keeping in view the actual operating conditions. The turbine was modeled with more than one FE ...
  • A systematic review of operating room ventilation 

    Sadrizadeh, Sasan; Aganovic, Amar; Bogdan, Anna; Wang, Cong; Afshari, Alireza; Hartmann, Anne; Croitoru, Cristiana; Khan, Amirul; Kriegel, Martin; Lind, Merethe; Liu, Zhijian; Melikov, Arsen; Mo, Jinhan; Rotheudt, Hansjörg; Yao, Runming; Zhang, Yixian; Abouali, Omid; Langvatn, Håkon; Sköldenberg, Olof; Cao, Guangyu (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-18)
    Ventilation systems are the primary way of eliminating airborne pathogenic particles in an operating room (OR). However, such systems can be complex due to factors such as different surgical instruments, diverse room sizes, various staff counts, types of clothing used, different surgical types and duration, medications, and patient conditions. OR ventilation should provide a thermally comfortable ...
  • Thermoelastic Investigation of Carbon-Fiber Reinforced Composites using Drop Weight Impact Test 

    Andleeb, Zahra; Malik, Sohail; Khawaja, Hassan; Nordli, Anders Samuelsen; Antonsen, Ståle; Hussain, Ghulam; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-28)
    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 ...
  • Multiphysics Analysis of Ice-Polyurethane Adhesion under Flexural Loading using FEM Analysis 

    Eidesen, Hans-Kristian; Andleeb, Zahra; Khawaja, Hassan; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-26)
    This paper presents the Finite Element Analysis (FEA) Multiphysics technique, applied to study the strength of ice adhesion between the surface of polyurethane and ice. The theoretical study of this work is based on the Euler-Bernoulli beam theory that is used to solve a four-point bending problem to give the correlation of displacements with load and longitudinal stresses. The physical samples were ...
  • Windtech – A Sensory Device for ‘Cold’ Sensation Measurements 

    Leyli, Amir Nadem; Khawaja, Hassan; Antonsen, Ståle; Swart, Daniel Kristoffer (Journal article; Tidsskriftartikkel, 2021-12-21)
    Windtech device is a novel tool for measuring the sensation of the ‘cold’. Cold poses numerous challenges for industrial operations, human survival, and living convenience. The impact of the cold is not possible to be quantified just based on temperatures; however other factors such as wind speed, humidity, irradiance have to be taken into consideration. Efforts have been made to develop combined ...
  • 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 ...

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