Viser treff 101-120 av 166

    • Hvordan kommuniserer lærere med elevene i teknologiprosjekter? 

      Lysne, Dag Atle; Esjeholm, Bjørn Tore (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-14)
      Inquiry-based methods have been seen as important for developing science in school. There are good reasons why the work of designing various technological devices in technology should also be part of inquiry-based methods. If so, it requires that the teachers have an exploratory approach in communicat-ing with students. In this paper, we analyze the communication between teachers and students in six ...
    • Finite element simulation of ductile fracture in polycrystalline materials using a regularized porous crystal plasticity model 

      Khadyko, Mikhail; Frodal, Bjørn Håkon; Hopperstad, Odd Sture (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-18)
      In the present study, a hypoelastic–plastic formulation of porous crystal plasticity with a regularized version of Schmid’s law is proposed. The equation describing the effect of the voids on plasticity is modified to allow for an explicit analytical solution for the effective resolved shear stress. The regularized porous crystal plasticity model is implemented as a material model in a finite element ...
    • Poly[2,2′-(4,4′-bipyridine)-5,5′-bibenzimidazole] functionalization of carbon black for improving the oxidation stability and oxygen reduction reaction of fuel cells 

      Berber, Mohamed R.; Mustafa, Mohamad Y. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-20)
      The rapid oxidation of carbon black (CB) is a major drawback for its use as a catalyst support in polymer electrolyte fuel cells. Here, we synthesize poly[2,20 -(4,40 -bipyridine)-5,50 -bibenzimidazole] (BiPyPBI) as a conducting polymer and use it to functionalize the surface of CB and homogenously anchor platinum metal nanoparticles (Pt-NPs) on a CB surface. The as-prepared materials were ...
    • Modelling Multi-layer Hydronic Radiators 

      Chen, Liguo; Sørensen, Bjørn Reidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-30)
      This report simulates Purmo type C22 and C33 radiators with both standard calculation and heat transfer method with help of Matlab/Simulink. Simulation results are presented to describe the radiators’ thermal performances with different simulation strategies. The deviations between two different calculation methods are identified and the heat transfer radiator model can be improved with more ...
    • Green Building in the Arctic Region: State-of-the-Art and Future Research Opportunities 

      Ravasio, Lucrezia; Sveen, Svein-Erik; Riise, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-10)
      The concept of Green Building refers to environmentally friendly constructions with the target of minimizing the impact on the natural environment through sustainable and efficient use of resources over their life cycle. Since modern buildings are large contributors to global energy consumption and greenhouse gas emissions, policies and international strategies intended to reduce the carbon footprint ...
    • Green Buildings in the Arctic region: a literature review 

      Ravasio, Lucrezia; Riise, Raymond; Sveen, Svein-Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-30)
      Green Buildings are defined as environmental-friendly buildings aimed at minimizing the impact on the natural environment through a sustainable and efficient use of resources over their life-cycle. This is, perhaps, a recently-introduced building concept that is increasingly gaining attention due to the policies and strategies intended to reduce the carbon footprint of conventional buildings, which ...
    • Ship resistance analysis using CFD simulations in Flow-3D 

      Deshpande, Sujay; Sundsbø, Per-Arne; Das, Subhashis (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-19)
      While designing the power requirements of a ship, the most important factor to be considered is the ship resistance, or the sea drag forces acting on the ship. It is important to have an estimate of the ship resistance while designing the propulsion system since the power required to overcome the sea drag forces contribute to ‘losses’ in the propulsion system. There are three main methods to calculate ...
    • Parametric Sensitivity of CSTBRs for Lactobacillus casei: Normalized Sensitivity Analysis 

      Das, Subhashis; Calay, Rajnish K; Chowdhury, Ranjana (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-18)
      In this paper, a sensitivity analysis of a continuous stirred tank bioreactor (CSTBR) was conducted to determine a parametrically sensitive regime. The growth of a lactic acid bacterium, namely, <i>Lactobacillus casei</i>, in a pH-controlled CSTBR was considered as a process model. Normalized objective sensitivities of the minimum pH were determined with respect to input parameters. A generalized ...
    • Product Inhibition of Biological Hydrogen Production in Batch Reactors 

      Das, Subhashis; Calay, Rajnish K; Chowdhury, Ranjana; Nath, kaustav; Eregno, Fasil (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-12)
      In this paper, the inhibitory effects of added hydrogen in reactor headspace on fermentative hydrogen production from acidogenesis of glucose by a bacterium, Clostridium acetobutylicum, was investigated experimentally in a batch reactor. It was observed that hydrogen itself became an acute inhibitor of hydrogen production if it accumulated excessively in the reactor headspace. A mathematical model ...
    • Fremtidens bygningsmaterialer 

      Gjerde, Klaus (Master thesis; Mastergradsoppgave, 2019-06-07)
      Bakgrunnen for oppgaven har vært å undersøke fremtidige bygningsmaterialer. Her er isolasjonsmaterialer og konstruksjonsmaterialer som betong, stål og massivtre gjennomgått. Det har i tillegg vært gjennomført et caseprosjekt hvor gjenbrukspotensialet for en bygning brukt i caseprosjektet har blitt vurdert. Videre ble livsløpsvurderinger for bygningen i caseprosjektet vurdert opp mot en tilsvarende ...
    • Kontroll av FDVU-dokumentasjon og sammenheng med byggskader. Modell for kontroll av forvaltning-, drift-, og vedlikeholdsdokumentasjon i byggesaker, samt en vurdering av sammenheng mellom byggeskader og manglende eller ufullstendig FDVU-dokumentasjon 

      Alsen, Aleksander (Master thesis; Mastergradsoppgave, 2019-06-07)
      Missing or incomplete documentation for management, operation, and maintenance can become a problem in relation to both cost and quality. This thesis presents demands and responsible roles in given such documentation and uses the new standard SN/TS 3456:2018 Documentation for management, operations, maintenance and development (FDVU-documentation) to prepare a checklist/control-form for this ...
    • Construction professionals’ perspectives on drivers and barriers of sustainable construction 

      Tokbolat, Serik; Karaca, Ferhat; Durdyev, Serdar; Calay, Rajnish K (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-05)
      With the associated environmental challenges and unsustainable patterns of construction, there is also notable awareness and willingness among the state bodies to adopt sustainability measures and practices in Kazakhstan. This study explores the drivers of and barriers inhibiting the adoption of sustainability paradigm in the construction context of Kazakhstan. The drivers and barriers were validated ...
    • Numerical study on the ventilation performance of a livestock house built in porous panels in Cold Regions 

      Mustafa, Mohamad; Xu, Yizhong; Calay, Rajnish K; Sørensen, Bjørn Reidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11)
      This paper presents a numerical prediction on the assessment of natural ventilation on a livestock house built in porous panels, aided by Computational Fluid Dynamics techniques. A typical climatic environment in Cold Regions was taken into consideration. The ventilation performances have been assessed by the distribution of indoor air velocity, turbulence intensity and local mean age of air through ...
    • Numerical study on the ventilation performance of a livestock house built in porous panels in Cold Regions 

      Xu, Yizhong; Mustafa, Mohamad; Calay, Rajnish K; Sørensen, Bjørn Reidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      This paper presents a numerical prediction on the assessment of natural ventilation on a livestock house built in porous panels, aided by Computational Fluid Dynamics techniques. A typical climatic environment in Cold Regions was taken into consideration. The ventilation performances have been assessed by the distribution of indoor air velocity, turbulence intensity and local mean age of air through ...
    • 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 ...
    • 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 ...
    • 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 ...
    • Effekt av basaltfiber for betongkvalitet = Effect of basalt fiber for quality of concrete 

      Ha, Duy Quang (Master thesis; Mastergradsoppgave, 2019-06-27)
      The need of concrete is getting more and more, experts have researched new materials to improve the good properties of concrete. Basalt fiber is a new additive in the concrete industry, so researches on basalt fiber concrete is not many. Previous research results have shown positive effects of basalt fiber on the mechanical strengths of the concrete. This task is performed by experiments to confirm ...
    • Samspillskontrakter – en vei å forene ulike interesser 

      Nielsen, Håvard Johannes (Master thesis; Mastergradsoppgave, 2019-06-27)
      Samspill i norsk bygg- og anleggsbransje øker i omfang. Hensikten med samspillsmodellene er å sørge for mer innovasjon i byggeprosjekter, samtidig som modellen skal motivere til kostnadseffektive løsninger. Tema for denne oppgaven er hvordan samspill kan nyttiggjøres i byggeprosjekter, og hvilke utfordringer og fordeler samspill kan medføre for byggherre. Oppgaven tar også for seg karakteristiske ...
    • Spesifikke energiforsyningskonsepter i Smart Arctic Building 

      Li, Lin (Master thesis; Mastergradsoppgave, 2019-06-27)
      I oppgaven utredes det spesifikk energiforsyningskonsepter og energikombinasjoner som gir lavest energibruk. Oppgaven ser på to eldre lavboligblokker som ligger i Beisfjordveien 88 og 90, som eies av Ofoten Midt-Troms Boligbyggerlag. Bygget har i dag lite isolasjon, og elektrisk energiforsyning som medfører stort varmetap og høyt energiforbruk på ca. 216 kWh/m2. Rehabiliteringen av blokker omfatter ...