• A field study of atmospheric icing analysis in a complex terrain of the high north 

      Rashid, Taimur; Mughal, Umair Najeeb; Mustafa, Mohamad; Virk, Muhammad Shakeel (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-12)
      Analyses of atmospheric icing events hold the key for computing the significant parameters leading to icing load calculations. In the cold regions of the high north, atmospheric icing loads on structures become important when it comes to design and safety of infrastructures. Furthermore, icing load calculations over a certain period of time provide a vital input for designers to improve the ...
    • Numerical investigation of vibration and dynamic pressure of a vertical axis wind turbine 

      Erchiqui, Fouad; Souli, M; Moatamedi, Mojtaba; Albahkali, E (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-12-31)
      In the environmental field, the problems of vibration reduction have become a major preoccupation, particularly on the noise generated by the acoustic radiation pressure produced by wind turbines. This paper is aimed at presenting the investigation on the application of FEM element method for study the acoustic radiation pressure produced by vertical-axis wind turbine. For this initiative, we ...
    • Using Mutual Charge Scheme to Measure Salinity of Ice 

      Mughal, Umair Najeeb; Nikumbh, Bhushan (Journal article; Peer reviewed; Tidsskriftartikkel, 2015)
      For offshore measurements in Cold Regions, salinity of ice is also a critical parameter (together with many other parameterssuchasicingtype,load,icingrateandmeltingrate)to be identified in order to optimize the performance of anti/de icing systems. Although there are some available sensory solutions in the market to measure real time salinity levels of water, however there are still not many real ...
    • Matrix factorization of multivariate Bernstein polynomials 

      Dalmo, Rune (Journal article; Peer reviewed; Tidsskriftartikkel, 2015)
      Ordinary univariate Bernstein polynomials can be represented in matrix form using factor matrices. In this paper we present the definition and basic properties of such factor matrices extended from the univariate case to the general case of arbitrary number of variables by using barycentric coordinates in the hyper-simplices of respective dimension. The main results in the paper are related to the ...
    • Shock Tube. Detail overview of equipment and instruments in the shock tube experimental setup 

      Khawaja, Hassan Abbas; Kapaya, Juma; Moatamedi, Mojtaba (Book; Bok, 2015)
      The shock tube is a device in which a normal shock wave is produced by the interaction of fluids at significantly high-pressure difference. The shock tube is comprised of two sections known as driver and driven sections. These two sections are interacted with the high-speed valve or a bursting disc. When the interaction happens, a shock wave forms almost instantaneously and propagates into the driven ...
    • A note on the best constants in some hardy inequalities 

      Persson, Lars Erik; Samko, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Abstract. The sharp constants in Hardy type inequalities are known only in a few cases. In this paper we discuss some situations when such sharp constants are known, but also some new sharp constants are derived both in one-dimensional and multi-dimensional cases.
    • Optimization of long-term performance of municipal solid waste management system: A bi-objective mathematical model 

      Yu, Hao; Solvang, Wei Deng; Li, Shiyun (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015)
      Management of municipal solid waste has becoming an extremely important topic for any urban authorities in recent years due to the rapidly increasing solid waste quantity and potential environmental pollution. In this paper, a bi-objective dynamic linear programming model is developed for decision making and supporting in the long-term operation of municipal solid waste management system. The proposed ...
    • Time scale Hardy-type inequalities with ‘broken’ exponent p 

      Oguntuase, James A; Fabelurin, Olanrewaju O; Adeagbo-Sheikh, Abdulaziz G; Persson, Lars Erik (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-01-16)
      In this paper, some new Hardy-type inequalities involving ?broken? exponents are derived on arbitrary time scales. Our approach uses both convexity and superquadracity arguments, and the results obtained generalize, complement and provide refinements of some known results in literature
    • Torque and Axial Loading Physics for Measuring Atmospheric Icing Load and Icing Rate 

      Mughal, Umair Najeeb; Virk, Muhammad Shakeel (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-01-31)
      Measuring icing load and icing rate are important parameters for an atmospheric icing sensor. A new icing sensor has recently been designed and developed at Narvik University College for measuring atmospheric icing rate, icing load and icing type. Unlike the existing atmospheric icing sensors commercially available in market, which uses the axial loading for measuring icing load and icing rate, this ...
    • Charge Transfer Scheme for Atmospheric Ice Sensing 

      Mughal, Umair Najeeb; Virk, Muhammad Shakeel; Rashid, Taimur (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-01-31)
      The atmospheric icing parameters are being measured nowadays with the aid of more customized yet limited commercial equipment. The parameters include atmospheric ice detection, icing load and icing rate. The robustness of such equipment is usually under scrutiny when it comes to cold/harsh environment operations. This phenomenon was experienced consistently by the atmospheric Icing Research Team at ...
    • Investigation of the Structure of Airflow Behind a Porous Fence Aided by CFD Based Virtual Sensor Data 

      Mustafa, Mohamad; Xu, Yizhong (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-28)
      Physical experiments have difficulties to thoroughly investigate the full structure of air flow behind a porous fence. Physical measurement sensors have their limitations of data acquisitions in turbulent air flow. Computational Fluid Dynamics (CFD) technique provides an infinite number of virtual sensors that allows producing quantitative CFD based virtual sensors data for users. In this paper, ...
    • Ownership Identification of Reindeer Calf Using Wireless Sensor Networks (WSN) 

      Mustafa, Mohamad (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-10)
      This paper presents a technique for identifying the ownership of new-born reindeer claves using wireless sensor networks (WSNs), which is an important tool that can be used to acquire useful information about animals’ activities and movements. Reindeer are semi wild and they give birth while in the wild. Although reindeer cows usually carry identification tags or signs of their owners, it is ...
    • Singularly perturbed spectral problems with Neumann boundary conditions 

      Piatnitski, Andrey; Rybalko, A; Rybalko, V (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-09-07)
      The paper deals with the Neumann spectral problem for a singularly perturbed second-order elliptic operator with bounded lower order terms. The main goal is to provide a refined description of the limit behaviour of the principal eigenvalue and eigenfunction. Using the logarithmic transformation, we reduce the studied problem to an additive eigenvalue problem for a singularly perturbed Hamilton–Jacobi ...
    • Some new Hardy-type inequalities for Riemann-Liouville fractional q-integral operator 

      Persson, Lars Erik; Shaimardan, Serikbol (Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-09-24)
      We consider the q-analog of the Riemann-Liouville fractional q-integral operator of order n∈Nn∈N. Some new Hardy-type inequalities for this operator are proved and discussed.
    • Estimation of upward radiances and reflectances at the surface of the sea from above-surface measurements 

      Kleiv, Øyvind; Folkestad, Are; Høkedal, Jo; Aas, Eyvind; Sørensen, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-02)
      During 4 field days in the years 2009–2011, 22 data sets of measurements were collected in the inner Oslofjord, Norway. The data consist of recordings of spectral nadir radiances in air and water as well as spectral downward irradiance in air. The studied wavelengths are 351, 400, 413, 443, 490, 510, 560, 620, 665, 681, 709 and 754 nm. The water-leaving radiance and the reflected radiance at the ...
    • A new discrete Hardy-type inequality with kernels and monotone functions 

      Kalybay, Aigerim; Persson, Lars Erik; Temirkhanova, Ainur (Peer reviewed; Journal article; Tidsskriftartikkel, 2015-10-06)
      A new discrete Hardy-type inequality with kernels and monotone functions is proved for the case 1<q<p<∞1<q<p<∞. This result is discussed in a general framework and some applications related to Hölder’s summation method are pointed out.
    • A note about frequencies being close or amplitudes being small in frequency analysis 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-10)
      In an earlier paper, an alternative method for how to solve the frequency analysis problem was offered. The object of the present paper is to bring about how to handle situations where the frequencies are close to each other or there is an amplitude that is really small.
    • A case study to estimate thermal conductivity of ABS in Cold Climate Chamber 

      Mughal, Umair Najeeb; Makarova, Marina; Virk, Muhammad Shakeel; Polanco Pinerez, Geanette (Journal article; Peer reviewed; Tidsskriftartikkel, 2015-10-22)
      Non steady state thermal conductivity of ABS was estimated using an analytical approach in a Cold Climate Chamber at ?10?C and ?14?C. Two hollow cylinders of ABS of varying thickness were used to estimate the conductivity. The material was porous but the porosity was unknown. This paper is a case study to understand, if it is reasonable to estimate the thermal conductivity using the analytical varying ...
    • Atmospheric ice accretion on non rotating vertical circular cyliner 

      Virk, Muhammad Shakeel; Mughal, Umair Najeeb; Polanco, Geanette (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-22)
      Study of atmospheric ice accretion on a non-rotating vertical circular cylindrical object was carried out at dry and wet ice conditions. Both numerical and experimental techniques were used during this study. 3D numerical study was carried out using computational fluid dynamics based approach, whereas experimental study was carried out at Cryospheric Environmental Simulator ‘CES’ in Shinjo, Japan. ...
    • Encapsulated Water Hammer: Theoretical/Experimental Study 

      Polanco, Geanette; Virk, Muhammad Shakeel; Mughal, Umair Najeeb; Victor, Sojo; Jose, Da Paixao; Antonio, Vidal; Orlando, Aguillon (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-22)
      Water hammer phenomenon involves the transformation of kinetic energy in pressure energy, this transformation occurs as the fluid conditions change inside the pipe in quite a short time. Industry requires to affront frequent flow interruptions in pipe systems due to the closing of valves or stopping of pumping equipment. This phenomenon can initiate serious damages like destruction of the pipe system ...