Browsing NTNU Open by Author "Åstrand, Per-Olof"
Now showing items 1-20 of 31
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A multiscale modelling of 2-aminoethanol (MEA) within the Python-ecosystem
Laurila, Kristine Inga Qing (Master thesis, 2024)En multiskala modelleringsmetode har blitt brukt for å studere referansemolekylet, 2-aminoetanol (MEA), i "etter-forbrenning fangst av karbondioksid" (PCC), med håp om å øke innsikten i konformasjonsstabilitet, ... -
Breakdown mechanisms in dielectric liquids for high voltage applications. - An experimental study on the propagation of 2nd mode streamers in dielectric liquids.
Willmann, Håkon Nilsen (Master thesis, 2018)Dielectric oils are frequently used as an insulating medium in high-voltage components such as transformers, capacitors and cables. Improving their insulating systems are essential to improving their performance. Dielectric ... -
Cerman: Software for simulating streamer propagation in dielectric liquids based on the Townsend–Meek criterion
Madshaven, Inge; Hestad, Øystein Leif Gurandsrud; Åstrand, Per-Olof (Peer reviewed; Journal article, 2021)We present a software to simulate the propagation of positive streamers in dielectric liquids. Such liquids are commonly used for electric insulation of high-power equipment. We simulate electrical breakdown in a needle–plane ... -
Chemical Bonding and Electronic Properties of the Co Adatom and Dimer Interacting with Polyaromatic Hydrocarbons
Mahmoodinia, Mehdi; Åstrand, Per-Olof; Chen, De (Journal article, 2015)The density functional calculations presented here elucidate the nature of the interaction between the Co atom and dimer with a polyaromatic hydrocarbon (PAH). The results are analyzed in terms of structural, electronic, ... -
Complex Frequency-Dependent Polarizability through the π → π* Excitation Energy of Azobenzene Molecules by a Combined Charge- Transfer and Point-Dipole Interaction Model
Haghdani, Shokouh; Davari, Nazanin; Sandnes, Runar; Åstrand, Per-Olof (Journal article; Peer reviewed, 2014)The complex frequency-dependent polarizability and π → π* excitation energy of azobenzene compounds are investigated by a combined charge-transfer and point-dipole interaction (CT/PDI) model. To parametrize the model, we ... -
Conductivity and capacitance of streamers in avalanche model for streamer propagation in dielectric liquids
Madshaven, Inge; Hestad, Øystein Leif Gurandsrud; Unge, Mikael; Hjortstam, Olof; Åstrand, Per-Olof (Journal article; Peer reviewed, 2019)Propagation of positive streamers in dielectric liquids, modeled by the electron avalanche mechanism, is simulated in a needle–plane gap. The streamer is modeled as an RC-circuit where the channel is a resistor and the ... -
Datadrevet Prediksjon av Båndgap for Multielement Krystallinske Materialer
Fjeldstad, Christopher Devik (Master thesis, 2019)Denne oppgaven undersøker bruken av datadrevet modellering for estimering av båndgap i multielement krystallinske materialer. Modellene ble utviklet gjennom bruk av lineære og ikke-lineære maskinlæringsalgoritmer på et ... -
Efficacy of commercial lithium-sulphur batteries versus commercially available lithium-ion batteries by proxy of electrochemical comparison
Korsbøen, Christoffer (Bachelor thesis, 2021)Litium-svovelbatterier (LSB) har blitt et område av interesse for ytterligere forbedring av litiumionbatteri (LIB) -teknologi. Gjennom stor teoretisk kapasitet og tilgjengelighet av råmateriale er LSB teknologi et mulig ... -
Electronic Structure, Stability, and Chemical Reactivity of Transition-Metal Catalysts Supported by Graphene Nanomaterials
Mahmoodinia, Mehdi (Doctoral theses at NTNU;2017:353, Doctoral thesis, 2017)Graphene, a 2D monolayer of graphite, has emerged as a novel material in many areas, such as catalysis and energy storage devices. Because of fascinating properties, such as remarkable surface area, superior electric ... -
Entropy Models and their Predictions of Phase Stability for High-Entropy Alloys
Hellerslia, Torje I. (Bachelor thesis, 2024)En ny kategori av legeringer ble foreslått i 2004, med sin distinksjon om at de har høy konfigurasjonell entropi. I den opprinnelige artikkelen pekte forfatterne på nettopp nettopp denne entropi-termen som stabiliserings ... -
Evolution of Carbon Nanofiber-Supported Pt Nanoparticles of Different Particle Sizes: A Molecular Dynamics Study
Cheng, Hong-ye; Zhu, Yi-An; Chen, De; Åstrand, Per-Olof; Li, Ping; Qi, Zhiwen; Zhou, Xing-Gui (Journal article, 2014)Molecular dynamics simulations employing the ReaxFF reactive force field have been carried out to analyze the structural evolution of fishbone-type carbon nanofiber-supported Pt nanoparticles, with particle size ranging ... -
Field-dependent molecular ionization and excitation energies: Implications for electrically insulating liquids
Davari, Nazanin; Åstrand, Per-Olof; Unge, Mikael; Lundgaard, Lars Esben; Linhjell, Dag (Journal article; Peer reviewed, 2014)Themolecular ionization potential has a relatively strong electric-field dependence as compared to the excitation energies which has implications for electrical insulation since the excited states work as an energy sink ... -
Geometrical flexibility of platinum nanoclusters: impacts on catalytic decomposition of ethylene glycol
Mahmoodinia, Mehdi; Trinh, Thuat; Åstrand, Per-Olof; Tran, Quang Khanh (Journal article; Peer reviewed, 2017)Catalytic decomposition of ethylene glycol on the Pt13 cluster was studied as a model system for hydrogen production from a lignocellulosic material. Ethylene glycol was chosen as a starting material because of two reasons, ... -
Influence of Carbon Support on Electronic Structure and Catalytic Activity of Pt Catalysts: Binding to the CO Molecule
Mahmoodinia, Mehdi; Åstrand, Per-Olof; Chen, De (Journal article, 2016)Single-atom catalysts, especially with single Pt atoms, exhibit potentially improved catalytic activity as compared to metal clusters and metal surfaces. Here, the atop and bridged bondings of the CO molecule on the Pt/C ... -
Lithium ion-water clusters in strong electric fields: A quantum chemical study
Daub, Christopher David; Åstrand, Per-Olof; Bresme, Fernando (Journal article, 2015)We use density functional theory to investigate the impact that strong electric fields have on the structure and energetics of small lithium ion–water clusters, Li+·nH2O, with n = 4 or 6. We find that electric field strengths ... -
Local electric field factors by a combined charge-transfer and point-dipole interaction model
Davari, Nazanin; Haghdani, Shokouh; Åstrand, Per-Olof; Schatz, George C. (Peer reviewed; Journal article, 2015)A force-field model for the local electric field as a linear response to a frequency-dependent external electric field is presented based on a combined charge-transfer and point–dipole interaction (CT-PDI) force-field model ... -
Local Field Factors and Dielectric Properties of Liquid Benzene
Davari, Nazanin; Daub, Christopher David; Åstrand, Per-Olof; Unge, Mikael (Journal article; Peer reviewed, 2015)Local electric field factors are calculated for liquid benzene by combining molecular dynamic simulations with a subsequent force-field model based on a combined charge-transfer and point-dipole interaction model for the ... -
Modeling the transition to fast mode streamers in dielectric liquids
Madshaven, Inge; Åstrand, Per-Olof; Hestad, Øystein Leif Gurandsrud; Unge, Mikael; Hjortstam, O. (Chapter, 2017)A simplified model for photoionization, modeling fast streamer propagation, is combined with an existing model for slow streamers, based on electron avalanches. Transitions from fast mode to slow mode, and from slow mode ... -
Optical rotation from coupled cluster and density functional theories
Haghdani, Shokouh (Doctoral theses at NTNU; 2018:31, Doctoral thesis, 2018)Chiral compounds are of fundamental importance in medical chemistry, biochemistry, and industry. Optical rotation, which is one of the most well-known optical responses of chiral molecules to an electromagnetic field, is ... -
Parametrization of a classical force field model (CT-PDI) for the calculation of molecular polarizablities
Skovereng, Sivert (Master thesis, 2023)To parametriseringer av en klassisk elektrostatisk modell for polariserbarheten er blitt gjennomført. Parametriseringene er gjennomført på et stort sett av små organiske molekyler, med mange vanlige funksjonelle grupper. ...