Sökning: "wave field excitation"

Visar resultat 1 - 5 av 34 avhandlingar innehållade orden wave field excitation.

  1. 1. On Ground and Structural Vibrations Related to Railway Traffic

    Författare :Johan O. Jonsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wave propagation; wave field excitation; soil structure interaction; structural vibration; ground vibration; traffic vibration;

    Sammanfattning : The continuous development and integration of railway infrastructure, especially within urban areas, can cause ground and building vibrations to reach levels that bring discomfort to people. The growing risk of damage to buildings located in areas prone to ground vibration should not be underestimated. LÄS MER

  3. 2. Prediction of random vibration using spectral methods

    Författare :Fredrik Birgersson; KTH; []
    Nyckelord :Spectral finite element method; distributed excitation; turbulent boundary layer measurements; random vibration; spectral super element method; wave expansion difference scheme; fluid-structure interaction;

    Sammanfattning : Much of the vibration in fast moving vehicles is caused bydistributed random excitation, such as turbulent flow and roadroughness. Piping systems transporting fast flowing fluid isanother example, where distributed random excitation will causeunwanted vibration. LÄS MER

  4. 3. On the Antenna-Channel Interactions: A Spherical Vector Wave Expansion Approach

    Författare :Andres Alayon Glazunov; Andreas F. Molisch; Michael A. Jensen; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antenna-channel interactions; wireless channels; MIMO; Antennas; propagation; spherical vector waves;

    Sammanfattning : The main focus of this thesis is the analysis of the interactions between antennas and channels where electromagnetic fields play a central role. Our goal has been to devise a general framework to enable a clear separation of the properties of the propagation channel from the influence of the antennas at the same time as it provides a common ground for a joint characterization of their properties. LÄS MER

  5. 4. Interaction between Electromagnetic Waves and Localized Plasma Oscillations

    Författare :Jan-Ove Hall; Thomas Leyser; Jan Trulsen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; space physics; plasma physics; radio waves; ionospheric modification; density depleations; field-aligned irregularities; lower hybrid solitary structures; lower hybrid cavities; Z mode waves; magnetosonic waves; scattering; mode conversion; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). LÄS MER

  7. 5. A Play of Light and Spins: Excitation and Detection of Non-linear Magnetization Dynamics using Light

    Författare :Shreyas Muralidhar; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spin waves; laser-induced magnetization dynamics; Brillouin light scattering; Spin Hall nano-oscillators; neuromorphic computing; Ising machines;

    Sammanfattning : The excitation and detection of magnetization dynamics play key roles in the field of spintronics and magnonics. In this thesis, we investigate a contactless method of exciting nonlinear magnetization dynamics using a femtosecond pulsed laser, and study the same with a Brillouin Light Scattering (BLS) microscope. LÄS MER