Now showing items 59-78 of 103

    • Multiphysics Simulation of Infrared Signature of an Ice Cube 

      Khawaja, Hassan Abbas; Rashid, Taimur; Eiksund, Oddmar; Broadal, Eivind; Edvardsen, Kåre (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-29)
      This paper presents numerical methodologies to simulate the Infrared (IR) signature of an ice cube. The ice was frozen in a cold environment (-28<sup>o</sup>C) and allowed to have uniform temperature throughout. It was then taken out and let to warm at room temperature conditions by means of natural convection. A 3D transient heat equation is solved using three different methodologies. In the first ...
    • Multiphysics Study of Forced Convection Conjugate Heat Transfer (CHT) Problem 

      Leyli, Amir Nadem; Moatamedi, Mojtaba; Alzahabi, Basem (Journal article; Peer reviewed, 2019)
      This paper 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.<p> In the given study, a hypothetical case is built where a heat source (a ...
    • Multiphysicsbased Condition Monitoring of Composite Materials 

      Xue, Hui; Sharma, Puneet; Khawaja, Hassan Abbas (Conference object; Konferansebidrag, 2015-12-10)
      Composites are increasingly being used in products such as: automobiles, bridges, boats, drillships, offshore platforms, aircrafts and satellites. The increased usage of these composite materials and the fact that the conditions pertaining to their failure are not fully understood makes it imperative to develop condition monitoring systems for composite structures. <br>In this work, we present a ...
    • Multivariate analysis of Co, Fe and Ni leaching from tailings following simulated temperature change 

      Fu, Shuai; Lu, Jinmei; Yuan, Fuqing (Journal article; Peer reviewed, 2018)
      A series of column leaching experiments were performed to understand the leaching behavior of Co, Fe and Ni in Ballangen mine tailings. Multivariate statistical approaches to evaluate potential risk variations in leachate quality and identifies temperature effects on their leaching behavior. Results from column leaching test indicated that the mobility of showed higher temperature may encourage ...
    • Nettverksorganisasjoners betydning for kunnskapstilgang og innovasjon 

      Underthun, Anders; Svare, Helge; Gausdal, Anne Haugen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-04)
      I denne artikkelen undersøker vi om regionale innovasjonsnettverksorganisasjoner (RINOer) bidrar til bedre kunnskapstilgang og innovasjon. Hvilke organiserte aktiviteter eller funksjoner i RINOen er i så fall relevante? Og i hvilken grad påvirker andre kjennetegn ved RINOene eller bedriftene som deltar, et slikt utfall? Bedriftene i studien rapporterer at RINO-deltakelsen har bidratt positivt både ...
    • A New Introductory Course in the Engineering Education at the University of Tromsø 

      Gjengedal, Arne Ketil; Schive, Tor (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      In 2011 a new national curriculum for the education of engineers was established in Norway. The objective of the curriculum is to ascertain that engineering education is professionally oriented, integrated, research-based and has a high academic standard. Institutions are instructed to facilitate a holistic approach to the engineering profession, which integrates social science, technology, science ...
    • Oil spill emergency preparedness in the Russian Arctic : a study of the Murmansk region. 

      Ivanova, Maria (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      The issue of oil spill emergency response in north-west Russia has become increasingly important following a substantial increase in maritime transport and major offshore developments in Russian waters. This study is an initial effort to outline the public and private agencies and organizations involved in handling oil spills in the Murmansk region and the structure of the oil spill emergency response ...
    • On RAM performance of production facilities operating under the Barents Sea harsh environmental conditions 

      Naseri, Masoud; Barabady, Javad (Peer reviewed, 2016-05-19)
      Oil and gas (O&G) industry is expanding its activities into Arctic offshore, where is characterised with severe operating conditions and less-developed infrastructure. Such conditions affect the reliability, availability, and maintainability (RAM) of offshore O&G plants, operations, and activities through different scenarios. Plant RAM analysis provides key information for decision-making on, for ...
    • Optimization of Pure-Component LNG Cascade Processes with Heat Integration 

      Eiksund, Oddmar; Brodal, Eivind; Jackson, Steven (Journal article; Tidsskriftartikkel, 2018-01-15)
      Liquefaction of natural gas is an energy-intensive process in which the energy efficiency depends on the number of compressors stages and the heat integration scheme. The aim of the study is to systematically evaluate process performance of pure component cascade processes, present optimized designs for all relevant numbers of compression stages and compare energy consumption between processes with ...
    • 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 ...
    • Overcoming Barriers to Proactive Response in Slow-onset Disasters 

      Staupe-Delgado, Reidar (Research report; Forskningsrapport, 2019)
      Disasters differ markedly in their speed of manifestation, which in turn greatly affects how researchers as well as authorities interpret and respond to them. In theory, disasters with a gradual and creeping onset are easier to manage than sudden and unexpected ones. However, the unfortunate reality is that hazards with a slow-onset are often ignored, left smouldering in the background, while their ...
    • Oxidative stress in two tropical species after exposure to diesel oil 

      Sardi Sulvarán, Adriana Eva; Sandrini-Neto, Leonardo; da S. Pereira, Leticia; Silva de Assis, Helena; Martins, Cesar C.; Lana, Paulo Da Cunha; Camus, Lionel (Peer reviewed, 2016-08-03)
      Recent offshore petroleum exploration has increased the risks of oil spills worldwide. We investigated biomarker responses to diesel oil exposure in two tropical and subtropical species, the clam Anomalocardia flexuosa and the polychaete Laeonereis culveri. Animals were exposed to oil-spiked sediment at two different concentrations (0.5 L and 1.0 L m−2). Activities of antioxidant enzymes catalase ...
    • Performance of an Ultrasonic Imaging System Based on a 45-MHz Linear PVDF Transducer Array: A Numerical Study 

      Brodal, Eivind; Melandsø, Frank; Jacobsen, Svein Ketil (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      New designs of high-resolution ultrasonic imaging systems that operate in the 30–100MHz region, for example, those based on linear transducer systems, are currently being investigated for medical purposes. Acoustic waves with frequencies in this range can detect microscopic structures in human tissue but will typically only penetrate a few mm because of large attenuation. However, this is sufficient ...
    • A practical guideline for human error assessment: A causal model 

      Ayele, Yonas Zewdu; Barabadi, Abbas (Peer reviewed; Konferansebidrag; Conference object, 2017-12-12)
      Abstract: To meet the availability target and reduce system downtime, effective maintenance have a great importance. However, maintenance performance is greatly affected in complex ways by human factors. Hence, to have an effective maintenance operation, these factors needs to be assessed and quantified. To avoid the inadequacies of traditional human error assessment (HEA) approaches, the application ...
    • Prediction of the long-term performance of green liquor dregs as a sealing layer to prevent the formation of acid mine drainage 

      Mäkitalo, Maria; Lu, Jinmei; Maurice, Christian; Öhlander, Björn (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-08)
      One of the mining industry's main concerns is the management of waste rock and tailings generated by sulfide ore extraction. Upon exposure of atmospheric oxygen, iron sulfides oxidize generating acidity. Infiltrating water form a metal-rich acidic leachate called acid mine drainage (AMD), that can cause serious environmental problems. Green liquor dregs (GLD) is a material that resists the passage ...
    • Probability mapping of scarred myocardium using texture and intensity features in CMR images 

      Kotu, Lasya Priya; Engan, Kjersti; Skretting, Karl; Måløy, Frode; Ørn, Stein; Woie, Leik; Eftestøl, Trygve (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The myocardium exhibits heterogeneous nature due to scarring after Myocardial Infarction (MI). In Cardiac Magnetic Resonance (CMR) imaging, Late Gadolinium (LG) contrast agent enhances the intensity of scarred area in the myocardium. In this paper, we propose a probability mapping technique using Texture and Intensity features to describe heterogeneous nature of the scarred myocardium in Cardiac ...
    • Review of Peltier and Resistive Heating Elements through Infrared Imaging 

      Taimur, Madiha; Rashid, Taimur; Khawaja, Hassan Abbas (Conference object; Konferansebidrag, 2016-12-08)
      The study includes the review of the heating elements to develop the fundamental understanding. The heating elements to be investigated are Peltier and Resistive types. Both have different working principles and they are used in various industrial applications for cooling and heating purposes. The Infrared (IR) wavelength is emitted by each object at a temperature above absolute zero. IR light is ...
    • Review of the phenomenon of fluidization and its numerical modelling techniques 

      Khawaja, Hassan Abbas (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-24)
    • Review of the Phenomenon of Ice Shedding from Wind Turbine Blades 

      Xue, Hui; Khawaja, Hassan Abbas (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-29)
      Wind power is a sustainable source of energy. However, there are certain challenges to be overcome. One of the operational challenges is the phenomenon of ice shedding. Icing happens on wind turbine blades in cold regions. When ice grows to a certain size, it separates from the wind turbine blades resulting in the phenomenon of ice shedding. This phenomenon is of significantly dangerous for equipment ...
    • Risikostyring i kommuner? 

      Nilsen, Aud Solveig (Research report; Forskningsrapport, 2013)