Recent additions

  • Feasibility study for utilization of solar energy in the arctic areas 

    Tamrakar, Stutee; Mustafa, Mohamad; Riise, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
    This research investigates a solar thermal system and a solar photovoltaic system which produces local energy, by incoming solar radiation, to meet the energy consumption demand of a residential building in the arctic region. The study on the use of the solar systems in the arctic areas is rare and often doubted. So, to analyze the potential of solar energy, a study case of an existing building block ...
  • Embeddings of weighted generalized Morrey Spaces into Lebesgue Spaces on fractal sets 

    Samko, Natasha Gabatsuyevna (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-19)
    We study embeddings of weighted local and consequently global generalized Morrey spaces defined on a quasi-metric measure set (X, d, μ) of general nature which may be unbounded, into Lebesgue spaces Ls(X), 1 ≤ s ≤ p < ∞. The main motivation for obtaining such an embedding is to have an embedding of non-separable Morrey space into a separable space. In the general setting of quasi-metric measure ...
  • PD+ based trajectory tracking of the underactuated quadrotor platform using dual quaternions 

    Johansen, Tor-Aleksander; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-29)
    We address the problem of state feedback trajectory tracking of the underactuated quadrotor platform in the dual quaternion framework through a PD+ tracking controller. The control law negates the need of generating a desired attitude trajectory as the translational error is mapped directly onto the rotational actuators through a virtual frame. More precisely, we show uniform practical asymptotic ...
  • Blending functions based on trigonometric and polynomial approximations of the Fabius function 

    Olofsen, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
    Most simple blending functions are polynomials, while more advanced blending functions are, for example, rational or expo-rational fractions. The Fabius function has the required properties of a blending function, but is a nowhere analytic function and cannot be calculated exactly everywhere on the required domain. We present a new set of trigonometric and polynomial blending functions with the shape ...
  • Finite element method application of ERBS triangles 

    Kravetc, Tatiana (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11)
    In this paper we solve an eigenvalue problem on a circular membrane with fixed outer boundary by using a finite element method, where an element is represented as an expo-rational blending triangle. ERBS triangles combine properties of B-spline finite elements and standard polynomial triangular elements. The overlapping of local triangles allows us to provide a flexible handling of the surface while ...
  • CFD modelling of pollutant transport from a docked marine vessel: Multiphysics 2019 [poster] 

    Madsen, Synne; Asier, Zubiaga; Khawaja, Hassan; Boiger, Gernot (Conference object; Konferansebidrag, 2019)
    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 ...
  • Qualitative visualization of the development of stresses through infrared thermography 

    Stange, Even; Andleeb, Zahra; Khawaja, Hassan (Journal article; Peer reviewed, 2019)
    In this work, the IR thermography was used to study the steel specimens (DIN 50125 Standard) undergoing the tensile tests. The tensile tests were performed using GUNT® Hamburg Universal Material Tester. The tensile specimens were clamped, and the test force was applied using a hand-operated hydraulic system. A dial gauge measured the elongation of the specimens. Using the WP 300.20 system for data ...
  • Non-parametric Linear Technique for Measuring the Efficiency of Winter Road Maintenance in the Arctic Area 

    Hatamzad, Mahshid; Polanco Pinerez, Geanette (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-05)
    Improving the performance of Winter Road Maintenance (WRM) can increase the traffic safety and reduce the cost as well as environmental impacts. This study evaluates the efficiency of WRM technique, named salting, in the Arctic area by using Data Envelopment Analysis (DEA), which is a non-parametric linear method to measure the efficiencies of decision-making units (DMUs) based on handling multiple ...
  • Multidimensional Hardy-type inequalities on time scales with variable exponents 

    Fabelurin, Olanrewaju O; Oguntuase, J. A.; Persson, Lars Erik (Journal article; Peer reviewed, 2019)
    A new Jensen inequality for multivariate superquadratic functions is derived and proved. The derived Jensen inequality is then employed to obtain the general Hardy-type integral inequality for superquadratic and subquadratic functions of several variables.
  • Ventilation and environmental control of underground spaces: A short review 

    Li, Angui; Kosonen, Risto; Melikov, Arsen; Yang, Bin; Olofsson, Thomas; Sørensen, Bjørn Reidar; Zhang, Linhua; Cui, Ping; Han, Ou (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-13)
    More and more underground spaces were used in 21st century because of rapid urbanization, traffic problems, etc. Underground city, metro, tunnel, mine, industrial and agriculture engineering, civil air defence engineering need large underground spaces. Underground spaces with different thermal, ventilation and lighting environments may cause comfort, health and safety problems. Concrete problems ...
  • Optimization of the CO2 Liquefaction Process-Performance Study with Varying Ambient Temperature 

    Jackson, Steven; Brodal, Eivind (Journal article; Peer reviewed, 2019-10-22)
    In carbon capture utilization and storage (CCUS) projects, the transportation of CO2 by ship can be an attractive alternative to transportation using a pipeline, particularly when the distance between the source and usage or storage location is large. However, a challenge associated with this approach is that the energy consumption of the liquefaction process can be significant, which makes the ...
  • Multiphysics study of infrared thermography (IRT) applications 

    Andleeb, Zahra; Ilyas, Muhammad; Khawaja, Hassan; Moatamedi, Mojtaba (Conference object; Konferansebidrag, 2019-12)
    Infrared thermography is the science of detecting infrared energy emitted from an object, converting it to apparent temperature, and producing images of that radiation, called thermograms. Infrared thermography means "beyond red temperature image". IR thermography being a remote non-contact/non-destructive means of testing is perfectly suitable for tests in extreme environments. Also, it is fast, ...
  • Best Venue to Disseminate Multiphysics Research 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2019-12)
    Multiphysics analysis has been developed over the recent past to better represent the behaviour of complex processes by the use of simultaneous modelling of a number of systems. This development is driven by the industrial need to further the understanding of real physical phenomena in order to develop and design safer and more efficient products which are environmentally friendly. Such analyses ...
  • The International Conference of MULTIPHYSICS 2020 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2019-12)
    Multiphysics analysis has become increasingly important in recent years due to demand in design and understanding of complex systems. The objective of the conferences is to share and explore findings on mathematical advances, numerical modelling and experimental validation of theoretical and practical systems in a wide range of applications.
  • The FlexNett Simulator 

    Bremdal, Bernt Arild; Tangrand, Kristoffer (Journal article; Peer reviewed, 2019)
    This paper documents research conducted in the Norwegian FLEXNETT project.<br>It describes a new tool that was developed to study the future impact of prosumers with PV panels on the grid in Norway and the potential energy flexibility that lies with residential prosumers. Systematic use of energy flexibility can be an important instrument for managing peak loads and voltage problems in weak power ...
  • Local energy markets as a solution for increased energy efficiency and flexibility 

    Ilieva, Iliana; Bremdal, Bernt Arild; de la Nieta Lopez, A.A.S.; Simonsen, S.H. (Journal article; Peer reviewed, 2019)
    With increasing share of distributed renewable energy resources in the grid and arising energy consumer awareness on environmental challenges new market models are sought where energy can be traded in an efficient and end-user centric way. This trend, together with the increasing consciousness on the benefits of local consumption and production has given rise to an increased focus on local energy ...
  • 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 ...
  • IR Thermography of Steel Specimens undergoing Tensile Tests 

    Stange, Even; Khawaja, Hassan (Conference object, 2018-12-13)
    In this work, the IR thermography was used to study the steel specimens (DIN 50125 Standard) undergoing the tensile tests. The tensile tests were performed using GUNT® Hamburg Universal Material Tester. The tensile specimens were clamped, and the test force was generated using a hand-operated hydraulic system. A dial gauge measured the elongation of the specimens. Using the WP 300.20 system for data ...
  • Surface Functionalization of Carbon Nanotubes for Energy Applications 

    Berber, Mohamaed; Hafez, Inas H.; Mustafa, Mohamad Y. (Peer reviewed; Chapter, 2018-05-05)
    Carbon nanotubes (CNTs) are receiving a great deal of attention as a catalyst support for different energy applications, due to their high surface area and high conductivity. Recent literature studies have shown that the application of CNTs mainly depends on their surface functionalization process. Typically, pristine CNTs (as produced) have no functional groups, which is usually considered as an ...
  • Droplet distribution spectrum effects on dry ice growth on cylinders 

    Sokolov, Pavlo; Virk, Muhammad (Journal article; Peer reviewed, 2019-01-06)
    A detailed parametric analytical study along with a series of viscid multiphase numerical simulations of ice accretion were performed in comparison with experimental data of ice accretion on a 30 mm diameter cylinder. The study was performed for droplet distribution spectra, Langmuir (A-J), in addition to an experimental droplet distribution obtained in an icing tunnel.<br>Analysis shows that droplet ...

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