• A first-principles Study of epitaxial Interfaces between Graphene and GaAs 

      Marthinsen, Astrid (Master thesis, 2014)
      Epitaxial interfaces between graphene and GaAs(111) have been investigated through a first-principles study using density functional theory (DFT). The GaAs(111) surface at the interface is assumed to be 2x2 reconstructed ...
    • Aging of Si3N4-bonded SiC Sidewall Materials in Hall-Héroult Cells: Material Characterization and Computer Simulation 

      Wang, Zhaohui (Doktoravhandlinger ved NTNU, 1503-8181; 2010:229, Doctoral thesis, 2010)
      Si3N4-bonded SiC materials have become the state-of-the-art sidewall block materials used in aluminium electrolysis cells. Despite its outstanding properties, the material properties degradate in the cell over time. The ...
    • Anode gas measurement during aluminium electrolysis 

      Sjøen, Rebecca V. (Master thesis, 2019)
      Gassanalyse ble gjennomført under aluminiumselektrolyse hvor en FTIR-gassmåler ble brukt. Laboppsettet ble lagd på en slik måte at det skulle minimere tilbakereaksjonen og Boudouard-reaksjonen. Hovedfokuset var å studere ...
    • Are MXenes Suitable as Cathode Material for Rechargeable Mg Batteries? 

      Kaland, Henning; Hadler-Jacobsen, Jacob; Fagerli, Frode Håskjold; Wagner, Nils Peter; Wang, Zhaohui; Selbach, Sverre Magnus; Vullum-Bruer, Fride; Wiik, Kjell; Schnell, Sondre Kvalvåg (Peer reviewed; Journal article, 2020)
      MXenes, a type of two-dimensional transition metal carbide/nitride, have received significant attention for electrochemical storage applications. With substantial capacities predicted for Mg ions, MXenes have been considered ...
    • Autopsy of refractory lining in anode kilns with open and closed design 

      Brandvik, Trond; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article, 2018)
      Aluminosilicate refractory lining constitutes a major part of anode baking kilns, and during anode baking the lining is exposed to harsh conditions which limits the lifetime. Here, autopsies of refractory linings from both ...
    • C-TiB2 Composite Inert Cathode Material by Spark Plasma Sintering 

      Håberg, Audun (Master thesis, 2018)
      TiB2 has been considered a potential inert, wettable cathode material for aluminum reduction cells for a long time. An important characteristic of TiB2 as a cathode material, is its excellent wetting properties towards ...
    • Carbon cathode wear in aluminium electrolysis cells 

      Senanu, Samuel; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2019)
      Autopsies of six spent potlinings with different carbon cathode block grades, amperage regimes and cell technologies were conducted at three separate smelters to reveal possible mechanisms causing cathode wear. Microstructure ...
    • Carbon Cathode Wear in Aluminium Electrolysis Cells 

      Senanu, Samuel; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Peer reviewed; Journal article, 2019)
      Autopsies of six spent potlinings with different carbon cathode block grades, amperage regimes and cell designs were conducted at three separate smelters to reveal possible mechanisms causing cathode wear. The microstructure ...
    • Cathode Wear Based on Autopsy of a Shutdown Aluminium Electrolysis Cell 

      Senanu, Samuel; Schøning, Christian; Rørvik, Stein; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2016)
      To investigate cathode wear, an autopsy of a shutdown aluminium electrolysis cell was conducted. The original lining consisted of a fully impregnated and graphitized carbon block and the cell was shut down after 2461 days ...
    • Cathode Wear in Aluminium Electrolysis Cells 

      Senanu, Samuel (Doctoral theses at NTNU;2019:317, Doctoral thesis, 2019)
      The increasing global demand for aluminium has resulted in growing production of aluminium metal through increased production capacity and improvement of the electrolysis technology. This has caused a development towards ...
    • Cathode Wear in Electrowinning of Aluminum Investigated by a Laboratory Test Cell 

      Wang, Zhaohui; Nobakhtghalati, Saeid; Støre, Anne; Solheim, Asbjørn; Tschöpe, Kati; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2016)
      The lifetime of an aluminum electrolysis cell is mainly determined by the cathode wear, especially for high amperage cells utilizing graphitized carbon cathodes. The cathode wear mechanisms are, however, complex and still ...
    • Degradation of Refractory Lining in Carbon Anode Baking Furnaces 

      Brandvik, Trond (Doctoral theses at NTNU;2019:340, Doctoral thesis, 2019)
      Primary aluminium metal is produced by electrochemical reduction of Al2O3 at ~960 ºC, during which large amounts of carbon anodes are consumed. The anodes are thus constituting an important part of the production process. ...
    • Development of an adaptive bilateral filter for evaluating color image difference 

      Wang, Zhaohui; Hardeberg, Jon Yngve (Journal article; Peer reviewed, 2012)
      patial filtering, which aims to mimic the contrast sensitivity function (CSF) of the human visual system (HVS), has previously been combined with color difference formulae for measuring color image reproduction errors. ...
    • Diffusion of alkali metals in the first stage graphite intercalation compounds by vdW-DFT calculations 

      Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor; Selbach, Sverre Magnus (Journal article; Peer reviewed, 2015)
      Diffusion of alkali metal cations in the first stage graphite intercalation compounds (GIC) LiC6, NaC6, NaC8 and KC8 has been investigated with density functional theory (DFT) calculations using the optPBE-vdW van der Waals ...
    • Direct Method for Producing Scandium Metal and Scandium-Aluminium Intermetallic Compounds from the Oxides 

      Martinez, Ana Maria Cuellar; Osen, Karen Sende; Gudbrandsen, Henrik; Sommerseth, Camilla; Wang, Zhaohui; Darell, Ove (Journal article; Peer reviewed, 2018)
      The electrochemical de-oxidation process, also called FFC-Cambridge process, has been proposed previously to produce reactive metals and their alloys through reduction of their metal oxides. The process works by introducing ...
    • Evaluating the smoothness of color transformations 

      Aristova, Anna; Wang, Zhaohui; Hardeberg, Jon Yngve (Proceedings of SPIE;7866, Journal article; Peer reviewed, 2011)
      Multi-dimensional look up tables (LUTs) are widely employed for color transformations due to its high accuracy and general applicability. Using the LUT model generally involves the color measurement of a large number of ...
    • Formation of aluminium carbide in Hall-Héroult electrolysis cell environments 

      Novák, Bronislav; Ratvik, Arne Petter; Wang, Zhaohui; Grande, Tor (Journal article; Peer reviewed, 2018)
      The formation and dissolution of aluminium carbide under conditions similar to the chemical and electrochemical environments in the Hall-Héroult process were studied in laboratory cells, including cells with reversed ...
    • Formation of Carbon Build-Up on the Flue Wall of Anode Baking Furnace 

      Wang, Zhaohui; Rørvik, Stein; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2017)
      A hard carbon build-up layer often forms on the flue wall surface in anode baking furnaces. The layer accumulates over thermal circles and needs to be mechanically removed regularly to ensure sufficient space for the anodes ...
    • Investigation of Spent Refractory Lining in an Anode Baking Furnace 

      Brandvik, Trond; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2017)
      The refractory lining in anode baking furnaces is exposed to harsh chemical environment and thermal cycling. Spent refractory lining from an anode baking furnace after 4000 days in operation was investigated. Variation in ...
    • Solvent-Controlled Charge Storage Mechanisms of Spinel Oxide Electrodes in Mg Organohaloaluminate Electrolytes 

      Wang, Lu; Wang, Zhaohui; Vullum, Per Erik; Selbach, Sverre Magnus; Svensson, Ann Mari; Vullum-Bruer, Fride (Journal article; Peer reviewed, 2017)
      Considering the improved safety, reduced cost, and high volumetric energy density associated with Mg batteries, this technology has distinct advantages for large-scale energy storage compared to other existing battery ...