Blar i tittel Artikler, rapporter og annet (automasjon og prosessteknologi)

Viser treff 149-163 av 163

    • 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 ...

    • Towards a Framework for Noctilucent Cloud Analysis 

      Sharma, Puneet; Dalin, Peter; Mann, Ingrid (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      In this paper, we present a framework to study the spatial structure of noctilucent clouds formed by ice particles in the upper atmosphere at mid and high latitudes during summer. We studied noctilucent cloud activity in optical images taken from three different locations and under different atmospheric conditions. In order to identify and distinguish noctilucent cloud activity from other objects ...

    • Transient Model of an RSW System with CO2 Refrigeration – A Study of Overall Performance 

      Brodal, Eivind; Jackson, Steven; Eiksund, Oddmar (Journal article; Peer reviewed; Tidsskriftartikkel, 2017-11-07)
      Refrigerated seawater (RSW) cooling using CO2 based refrigeration is a relatively new technology that shows promising performance in cold climates. For being a refrigerant CO2 has a low global warming potential (GWP) and is therefore recognized as an environmentally friendly alternative if the unit is competitive on energy efficiency. However, RSW systems with CO2 have a significant reduction in ...

    • A two-component nonlinear variational wave system 

      Nordli, Anders Samuelsen; Aursand, Peder Kristian (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-14)
      We derive a novel two-component generalization of the nonlinear variational wave equation as a model for the director field of a nematic liquid crystal with a variable order parameter. The equation admits classical solutions locally in time. We prove that a special semilinear case is globally well-posed. We show that a particular long time asymptotic expansion around a constant state in a moving ...

    • UA and pinch point temperature difference modeling — Finding the best heat exchanger schemes 

      Brodal, Eivind; Jackson, Steven; Hailu, Getu (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-28)
      Process models using simplified heat exchanger (HE) models are often analyzed using methods based on derivatives or optimization procedures, where even small numerical errors can cause algorithms to fail. This article explores the use of numerical approximations for calculating pinch temperature and UA-value, including novel high-order polynomial methods using equidistant and Chebyshev grids. The ...

    • Understanding Physical Properties of Fresh Water and Marine Ice using Multiphysics Modelling and Infrared Thermography 

      Khawaja, Hassan (Conference object; Konferansebidrag, 2023)
      Ice has unique physical properties, which tend to vary depending on how, where, and when it forms. In the presented work, we looked deeper into various physical properties of ice. In one of the studies, we focused on studying the ice adhesion on two types of polymers; polyurethane (PU) and polyvinyl-chloride (PVC). It revealed interesting behaviors with a viable potential for roads/highways coated ...

    • Using Deep Learning Methods for Segmenting Polar Mesospheric Summer Echoes 

      Domben, Erik Seip; Sharma, Puneet; Mann, Ingrid (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-31)
      Polar mesospheric summer echoes (PMSE) are radar echoes that are observed in the mesosphere during the arctic summer months in the polar regions. By studying PMSE, researchers can gain insights into physical and chemical processes that occur in the upper atmosphere—specifically, in the 80 to 90 km altitude range. In this paper, we employ fully convolutional networks such as UNET and UNET++ for ...

    • Using Infrared Thermography and Multiphysics Modelling to Investigate Ice 

      Khawaja, Hassan (Conference object; Konferansebidrag, 2022)

    • Validation of air ventilation in tunnels, using experiments and computational fluid dynamics 

      Myrvang, Torgeir; Khawaja, Hassan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      The study presented in this paper concerns the ventilation system inside tunnels. The ventilation system is responsible for the removal of exhaust gases produced by vehicles and for providing a clear view throughout the tunnels in routine operations and in the event of fire. The ventilation system has several stages, which are equipped with one or more fans and can be activated together or separately. ...

    • 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 ...

    • What is Multiphysics? Definition and Examples 

      Khawaja, Hassan Abbas (Conference object; Konferansebidrag, 2023-11)

    • Why collaboration is necessary for research in academia? 

      Khawaja, Hassan (Conference object; Konferansebidrag, 2022-05-23)

    • Windtech Technology - Measuring Cold Exposure via Conjugate Heat Transfer 

      Khawaja, Hassan (Conference object; Konferansebidrag, 2020)
      Windtech technology is based on a novel patented technique of measuring cold exposure (UK Patent Office Application Number: 1914757.8, titled: Measuring cold exposure, dated: 11th October 2019). In this technology, the cold is measured via the response of an electrical heater exposed to environmental elements such as ambient temperature, wind, humidity, and irradiance. In this technology, the heater ...

    • 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 ...

    • Zonal modeling of air distribution impact on the long-range airborne transmission risk of SARS-CoV-2 

      Aganovic, Amar; Cao, Guangyu; Kurnitski, Jarek; Melikov, Arsen; Wargocki, Pawel (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-28)
      A widely used analytical model to quantitatively assess airborne infection risk is the Wells-Riley model which is limited to complete air mixing in a single zone. However, this assumption tends not to be feasible (or reality) for many situations. This study aimed to extend the Wells-Riley model so that the infection risk can be calculated in spaces where complete mixing is not present. Some more ...