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Particles and Radiation
Published in Rob Appleby, Graeme Burt, James Clarke, Hywel Owen, The Science and Technology of Particle Accelerators, 2020
Rob Appleby, Graeme Burt, James Clarke, Hywel Owen
In general, radiation damping is the phenomenon of the reduction of some charge's oscillation amplitude due to the emission of radiation. For example, in the classical description of an electron orbiting an atomic nucleus, the (classical) emission of radiation by the charge would cause it to spiral inwards into the nucleus in some time t∼10−8 s. In particle accelerators, the term is used to describe the effect of what is basically a quantum phenomenon; it arises particularly in the context of electron storage rings, an important case we describe here.
Nanoparticle Plasmon Waveguides
Published in Sergey I Bozhevolnyi, Plasmonic, 2019
Radiation damping is caused by a direct radiative decay route of the coherent electron oscillation into photons,10 and is the main cause of the weakening of the strength of the dipole plasmon resonance as the particle volume increases.11 Thus, despite the fact that an increase in particle volume decreases the strength of the non-radiative decay pathway (namely absorption), a significant broadening of the plasmon resonance sets in.
Soil–structure Interaction and Vertical-horizontal Coupling Effects in Buildings Isolated by Friction Bearings
Published in Journal of Earthquake Engineering, 2022
SSI effects are further classified as a kinematic interaction effect and an inertial interaction effect (Kausel 2010). In the kinematic interaction effect, the free-field earthquake motion, i.e. the motion of the ground when no building exists, is modified at the building site due to the rigidity of the foundation at or below the ground surface. This interaction can be neglected if the foundation dimensions are small compared to the wavelength of the ground motion (ATC and CUREE, 2012; Clough and Penzien 2003). The inertial interaction effect occurs when inertial forces caused by the vibration of the superstructure deform the soil under the structure, which in turn affects the vibration of the superstructure. The deformation of soil also propagates vibration energy, which adds damping to the system. This damping is referred to as radiation damping. Note that this damping is an addition to the hysteretic damping, which comes from the hysteretic behavior due to nonlinear deformation of the soil.
Structural damage identification incorporating uncertain boundary flexibility by ensemble couple sparse coding classification method
Published in European Journal of Environmental and Civil Engineering, 2021
Maryam Vahedi, Faramarz Khoshnoudian, Milad Fallahian, Fariba Shadan
One of the common methods that can be used to investigate the SSI effects is the substructure approach in which the soil structure interaction problem is partitioned into distinct parts that are combined to formulate the complete solution (National Institute of Standards and Technology, 2012). In this method, a dynamic impedance matrix, representative of the dynamic response of the soil-foundation system has to be calculated. The removal of energy from the system is referred to as radiation damping. Viscous dampers can be introduced to take into account the radiation damping. The coefficients of the viscous dampers are proportional to the wave velocity of the soil and the foundation geometry. The compliance of soil foundation corresponds to a stiffness value which can be modelled by springs. Stiffness properties can be combined with radiation damping properties as a complex impedance function.