The goals of this project are to utilize shipborne remote sensing to understand the scattering and attenuation process of ocean waves interacting with ice. A dedicated nautical X-band radar on a vessel would be used to follow the propagation of waves into the marginal ice zone (MIZ) and observe the attenuation and scattering of wave modes from the floating ice as well as estimate surface wind a...

In this work, the problem of Rayleigh wave propagation is considered in the context of the theory of thermoelastic diffusion. The formulation is applied to a homogeneous isotropic thermoelastic half space with mass diffusion at the stress free, isothermal, isoconcentrated boundary. Using the potential functions and harmonic wave solution, three coupled dilatational waves and a shear wave is obt...

BACKGROUND Prior research has suggested a weaker parasympathetic antagonism of sympathetic effects on the heart in type A (coronary-prone) men. To confirm this phenomenon and extend our understanding of it, we investigated the effects of prior muscarinic blockade on the electrocardiogram T wave and other cardiovascular and neuroendocrine responses to isoproterenol in type A and type B (non-coro...

A unified theory of sound propagation in saturated marine sediments is developed on the basis of a linear wave equation, which includes a new dissipation term representing internal losses arising from interparticle contacts. This loss mechanism, which shows a ‘‘memory’’ or hysteresis, is proposed as being responsible for the acoustic properties of sediments. To accommodate the memory, the loss ...

Seismic attenuation measurements provide a powerful tool for sampling mantle properties. Laboratory experiments provide calibrations at seismic frequencies and mantle temperatures for dry meltfree rocks, but require 10210 extrapolations in grain size to mantle conditions; also, the effects of water and melt are not well understood. At the same time, body wave attenuation measured from dense bro...

This paper mainly introduces the Wideband 5-bit MMIC digital attenuator with high precision. Firstly, the theories of basic GaAs digital attenuator MMIC’s configurations are searched. Secondly, every possible configuration is contrasted, subsequently, appropriate topology is selected for each stage. This attenuator has been realized by 0.5!m GaAs pHEMT process. Simulation results of the digital...

Multiple scattering of waves induces bulk effects such as attenuation and anisotropy that are important in seismology, optics, medical imaging, and other fields involving propagation in disordered media. We report here measurements of ultrasonic surface wave propagation in a strong-scattering, quasiperiodic medium consisting of a grooved surface of aluminum. Using noncontacting optical methods ...

Dislocations in solids contribute to anelastic attenuation, relaxation of the shear modulus, transient creep, and steady state flow. These properties of the mantle may therefore be related. The glide and climb of dislocations appear to have the appropriate time constants to explain seismic wave attenuation and mantle viscosity, respectively. The dislocation density of the mantle depends on the ...

Contrary to the traditional view, seismic attenuation in Biot's theory of uid-saturated porous media is due to viscous damping of local (not global) pore-uid motion. Since substantial inhomogeneities in uid permeability of porous geological materials are to be expected, the regions of highest local permeability contribute most to the wave energy dissipation while those of lowest permeability do...

Compressional waves in heterogeneous permeable media suffer attenuation fiom both scattering and induced pore scale flow of the viscous saturating fluid. Stochastic medium theories are used to describe scattering on multiple length scales, and are validated by numerical examples using a dual length scale sedimentary sequence taken from a producing oil reservoir. The highly variable permeability...