This paper investigates the feasibility to use an electrodynamic loudspeaker to determine viscoelastic properties of sound-absorbing materials in the audible frequency range. The loudspeaker compresses the porous sample in a cavity, and a measurement of its electrical impedance allows one to determine the mechanical impedance of the sample: no additional sensors are required. Viscoelastic prope...

Using Biot's theory, a set of boundary conditions is presented for wave transmission and reflection at the contact surface between an elastic medium (fluid or solid) and a fluid-saturated porous solid (Biot medium). The analysis shows the continuity of the normal component of the density energy flux vectors across the contact surfaces, so that total energy is preserved. Energy reflection and tr...

This study explores heat diffusion effects inmicro-channel heat sinks intended for electronic cooling applications. Detailed analytical models are constructed for heat sinks havingmicro-channels with rectangular, inverse trapezoidal, triangular, trapezoidal, anddiamond-shaped cross sections. Solutions are presented for both monolithic heat sinks and heat sinks with perfectly insulating cover pl...

In this paper we determine the velocity, the energy, and estimate writhe and twist helicity contributions of vortex filaments in the shape of torus knots and unknots (as toroidal and poloidal coils) in a perfect fluid. Calculations are performed by numerical integration of the Biot-Savart law. Vortex complexity is parametrized by the winding number w given by the ratio of the number of meridian...

Expanding upon an observation of Hou [Math. Comp., submitted], exact desingularizations are presented of the Euler equations in two and three dimensions for which the singularity within the Biot-Savart integrand is reduced by one order. The reformulated equations are then solved numerically using either the point vortex method or the vortex blob method. The increased smoothness of the Biot-Sava...

Seismoelectric phenomena in sediments arise from acoustic wave-induced fluid motion in the pore space, which perturbs the electrostatic equilibrium of the electric double layer on the grain surfaces. Experimental techniques and the apparatus built to study the conductivity dependence of the electrokinetic (EK) effect are described and outcomes for studies in loose glass microspheres and medium-...

Biological resources are the basis of much of this Nation’s prosperity. The wise stewardship of these riches affects current and future generations and, therefore, must be rooted in decisions based on the best information available. Because of the rapid growth of all content on the Internet, there is a corresponding increase in online biological information of all types. However, the sheer volu...

In this work, we present a comprehensive study of several partitioned methods for the coupling of flow and mechanics. We derive energy estimates for each method for the fully discrete problem. We write the obtained stability conditions in terms of a key control parameter defined as a ratio of the coupling strength and the speed of propagation. Depending on the parameters in the problem, give th...

[1] A model has been developed to calculate the perturbed magnetic field at various ground-based magnetometer sites using the output of the ionospheric currents from the Lyon-Fedder-Mobarry Global MHD code. The model uses the computed ionospheric currents and the height dependence of the electrojet current above the ground, by evaluating the penetration depth of the precipitating energetic elec...

It is shown that in the initial phase there are two basic types of similar folding of multiother. The dominant wave length obtained in foldlayered structures, referred to here al folding of ing of the second kind is the same as derived the first and second kind. denending on the orevapr&iously (Biot, 1961) assuming the incompetent lence of over-all flexure or hear. K simple Lory layers to act a...