Sökning: "Effective interaction energy"

Visar resultat 21 - 25 av 141 avhandlingar innehållade orden Effective interaction energy.

  1. 21. Modelling and Simulation of Reactor Pressure Vessel Failure during Severe Accidents

    Författare :Peng Yu; Weimin Ma; Walter Villanueva; Sevostian Bechta; Florian Fichot; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RPV failure; thermo-fluid-structure coupling; creep modelling; melt pool heat transfer; severe accident; CFD; FEA; transIVR;

    Sammanfattning : This thesis aims at the development of new coupling approaches and new models for the thermo-fluid-structure coupling problem of reactor pressure vessel (RPV) failure during severe accidents and related physical phenomena. The thesis work consists of five parts: (i) development of a three-stage creep model for RPV steel 16MND5, (ii) development of a thermo-fluid-structure coupling approach for RPV failure analysis, (iii) performance comparison of the new approach that uses volume loads mapping (VLM) for data transfer with the previous approach that uses surface loads mapping (SLM), (iv) development of a lumped-parameter code for quick estimate of transient melt pool heat transfer, and (v) development of a hybrid coupling approach for efficient analysis of RPV failure. LÄS MER

  3. 22. The interaction of hydrogen with metallic glass

    Författare :Johan Bylin; Gunnar K. Pálsson; Ralph H. Scheicher; Gabriella Andersson; Astrid Pundt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; metallic glass; hydrogen; thin film; density functional theory; stochastic quenching; molecular dynamics; x-ray diffraction; pair distribution function; neutron reflectometry; volume expansion; elastic hydrogen-hydrogen interaction; dipole force tensor; electronic structure; optical conductivity; resistivity; optical transmission; x-ray photoelectron spectroscopy; thermodynamic driving force; Gibbs free energy; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : Combining theoretical ab initio calculations with high-purity thin film sample synthesis and in situ measurements is a compelling way to bridge the gap in our understanding concerning hydrogen in metallic glasses, which is the primary work of this dissertation thesis. The main emphasis has been on how hydrogen affects the structure of metallic glasses, and how those changes influence not only the electronic properties of the amorphous metals but also their thermal stability. LÄS MER

  4. 23. Sea Level Compensation System for Wave Energy Converters

    Författare :Valeria Castellucci; Rafael Waters; Ronan Costello; Uppsala universitet; []
    Nyckelord :Ocean energy; Tides; Linear generator; Point absorber; Offshore experiment; Hydro-mechanic modeling; Power absorption; Control system; Communication system; Measurement system; Lysekil research site; Wave Hub.;

    Sammanfattning : The wave energy converter developed at Uppsala University consists of a linear generator at the seabed driven by the motion of a buoy on the water surface. The energy absorbed by the generator is negatively affected by variations of the mean sea level caused by tides, changes in barometric pressure, strong winds, and storm surges. LÄS MER

  5. 24. Phase-field modeling of surface-energy driven processes

    Författare :Klara Asp Grönhagen; John Ågren; Suzana Fries; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Phase-field method; surface energy; solute drag; solid-state sintering; multicomponent multiphase flow; wetting; liquid-phase sintering; spinodal decomposition; CALPHAD; Materials science; Teknisk materialvetenskap;

    Sammanfattning : Surface energy plays a major role in many phenomena that are important in technological and industrial processes, for example in wetting, grain growth and sintering. In this thesis, such surface-energy driven processes are studied by means of the phase-field method. LÄS MER

  7. 25. Tailoring the magnetic order in mesoscopic spin systems

    Författare :Henry Stopfel; Vassilios Kapaklis; Hjörvarsson Björgvin; Unnar Arnalds; John Cumings; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; artificial spin ice; magnetic nano-structures; mesoscopic spin systems; mesospins; model systems; Shakti; Saint George; interaction modifier; engineering of energy-landscape; multiple energy-scales; Fysik; Physics;

    Sammanfattning : Mesoscopic spin systems can be designed and fabricated using modern nano-fabrication techniques. These systems can contain large numbers of patterned ferromagnetic elements, for which the shape will generally determine their effective mesospin dimensionality. LÄS MER