Browsing Institutt for fysikk by Author "Walmsley, John"
Now showing items 1-13 of 13
-
Copper enriched by dealloying as external cathode in intergranular corrosion of aluminium alloy AA6005
Kumari, Shilpa; Wenner, Sigurd; Walmsley, John; Lunder, Otto; Nisancioglu, Kemal (Journal article; Peer reviewed, 2019)The purpose of this work is to understand the role of Cu in the propagation mechanism of IGC on extruded alloy AA6005-T5. The constituent Cu segregates as a Cu-rich nanolayer, together with the formation of a solute depleted ... -
Evaluation of ORR active sites in nitrogen-doped carbon nanofibers by KOH post treatment
Muthuswamy, Navaneethan; Buan, Marthe Emelie Melandsø; Walmsley, John; Rønning, Magnus (Journal article; Peer reviewed, 2018)Oxygen reduction on N-doped carbon nanomaterials is believed to take place at either N-centered active sites (C-Nx) or Fe-centered active sites (Fe-Nx). In this work the origin of the oxygen reduction on nitrogen-doped ... -
Evaluation of Reoxidation Thresholds for γ-Al2O3-Supported Cobalt Catalysts under Fischer - Tropsch Synthesis Conditions
Tsakoumis, Nikolaos; Walmsley, John; Rønning, Magnus; van Beek, Wouter; Rytter, Erling; Holmen, Anders (Journal article; Peer reviewed, 2017)Size-dependent phenomena at the nanoscale influence many applications, notably in the science of heterogeneous catalysis. In cobalt-based Fischer–Tropsch synthesis (FTS), the size of Co nanoparticles (NPs) dictates to a ... -
High Temperature Decomposition of Methane on Quartz Pellets
Lindgaard, Henrik (Master thesis, 2015)This work has shown that pure methane, when exposed to quartz at a temperatures of 900°C and 1000°C, cracks and deposits carbon at a near constant rate. The deposition rates for the individual temperature levels were shown ... -
Investigation of Co2AlO4/CeO2 Catalyst for N2O Abatement using Electron Microscopy Techniques
Berntsen, Ørjan Uteng (Master thesis, 2014)A N2O abatement catalyst of a Co2AlO4 active phase and CeO2 support phase has been investigated using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and scanning electron microscopy ... -
Methane activation on bimetallic catalysts: properties and functions of surface Ni-Ag alloy
Dam, Anh Hoang; Wang, Hongmin; Dehghan-Niri, Roya; Yu, Xiaofeng; Walmsley, John; Holmen, Anders; Yang, Jia; Chen, De (Peer reviewed; Journal article, 2019)The paper presents a fundamental study of the properties and functions of well‐defined Ni−Ag surface alloys in methane decomposition and steam reforming, aiming at providing a better understanding of the principle for ... -
Nanostructural Analysis of Co-Re/γ-Al2O3 Fischer-Tropsch Catalyst by TEM and XRD
Dehghan-Niri, Roya; Tsakoumis, Nikolaos E.; Voronov, Alexey; Holmen, Anders; Holmestad, Randi; Vullum, Per Erik; Borg, Øyvind; Rytter, Erling; Rønning, Magnus; Walmsley, John (Journal article; Peer reviewed, 2022)A rhenium promoted Fischer-Tropsch (FT) cobalt catalyst supported on γ-Al2O3 has been investigated by Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD), before and after reduction. Electron diffraction, ... -
Optical response of rectangular array of elliptical plasmonic particles on glass revealed by Mueller matrix ellipsometry and finite element modeling
Walmsness, Per Magnus; Brakstad, Thomas Vågenes; Svendsen, Brage Bøe; Banon, Jean-Philippe Armand; Walmsley, John; Kildemo, Morten (Peer reviewed; Journal article, 2019)We report here on the optical response of elliptical gold particles arranged in a rectangular lattice on glass and probed at non-normal incidence in reflection using spectroscopic Mueller matrix ellipsometry in the energy ... -
Photoemission spectroscopies and their application in solid state and material physics
Mazzola, Federico (Doctoral thesis at NTNU;2016:97, Doctoral thesis, 2016)Understanding the electronic properties of solid state systems is of fundamental importance to all matter. In particular, understanding and tailoring the properties of bound electrons in materials is an indispensable step ... -
Precipitation in an extruded AA7003 aluminium alloy: Observations of 6xxx-type hardening phases
Lervik, Adrian; Marioara, Calin Daniel; Kadanik, Maria; Walmsley, John; Milkereit, Benjamin; Holmestad, Randi (Journal article; Peer reviewed, 2019)Precipitation behaviour in an industrially extruded AA7003 alloy has been studied using Transmission Electron Microscopy (TEM) together with Differential Scanning Calorimetry (DSC). Air Cooling (AC) after solution heat ... -
Progress in Understanding Initiation of Intergranular Corrosion on AA6005 Aluminum Alloy with Low Copper Content
Kumari, Shilpa; Wenner, Sigurd; Walmsley, John; Lunder, Otto; Nisancioglu, Kemal (Journal article; Peer reviewed, 2019)As part of an extensive research program to study recent, unexpected intergranular corrosion (IGC) on 6xxx series aluminum alloys (AlMgSi), this paper investigates the mechanism of initiation and early propagation of IGC ... -
Structural properties of Ge doped multicrystalline Silicon wafers and Solar cells
Lilliestråle, Johan Carl Åke (Master thesis, 2012)The efficiency of multi crystalline silicon solar cells is around 17% but the theoretical limit is 33,7 %. Impurities and dislocations are the main sources for degradation of the solar cell efficiency, especially the ... -
X-ray absorption, X-ray diffraction and electron microscopy study of spent cobalt based catalyst in semi-commercial scale Fischer-Tropsch synthesis
Tsakoumis, Nikolaos; Dehghan-Niri, Roya; Rønning, Magnus; Walmsley, John; Borg, Øyvind; Rytter, Erling; Holmen, Anders (Peer reviewed; Journal article, 2014)Calcined, reduced and spent Co-Re/γ-Al2O3 catalysts for Fischer–Tropsch synthesis (FTS) were characterized and compared. Co-K-edge and Re-LIII-edge X-ray absorption near edge structure (XANES), X-ray powder diffraction ...