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- Hanson, G. W., et al.
(författare)
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Electromagnetic absorption mechanisms in metal nanospheres: Bulk and surface effects in radiofrequency-terahertz heating of nanoparticles
- 2011
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:12
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Tidskriftsartikel (refereegranskat)abstract
- We report on the absorption of electromagnetic radiation by metallic nanoparticles in the radio and far infrared frequency range, and subsequent heating of nanoparticle solutions. A recent series of papers has measured considerable radio frequency (RF) heating of gold nanoparticle solutions. In this work, we show that claims of RF heating by metallic nanoparticles are not supported by theory. We analyze several mechanisms by which nonmagnetic metallic nanoparticles can absorb low frequency radiation, including both classical and quantum effects. We conclude that none of these absorption mechanisms, nor any combination of them, can increase temperatures at the rates recently reported. A recent experiment supports this finding.
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2. |
- Hanson, Hans, et al.
(författare)
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Implications of Morphodynamic Time-Scale for Coastal Protection
- 2005
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Ingår i: Coastal Engineering 2004, Vols 1-4. - : World Scientific Publishing Company. ; , s. 2620-2632
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Konferensbidrag (refereegranskat)abstract
- As reported in several studies, even though properly designed, it is possible that groin systems not only cause down-drift beaches to erode, but also contribute to the generation of rip currents. These rip currents run along the updrift side of the structure, moving sediment offshore where it may be, at least in part, lost from the system. It is well known that the directionality of the incident waves is a central factor for the shoreline response to groins. Until now, however, this directionality has been characterized only by the ratio of net transport rate Q(n) to gross transport rate Q(g). In this study it is concluded that the phase lag between the forcing and the morphodynamic response is another key factor responsible for these offshore losses. Based upon this, a relaxation time for open-coast systems and a non-dimensional morphodynamic response factor for groin compartments are introduced as new design parameters for groin systems. These parameters provide an indication about the time it takes for the morphodynamic system to adjust to a change in the hydrodynamic forcing conditions.
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