We demonstrate that a homogeneous porous medium composed of sedimentary particles develops channels due to curvature driven growth of fluid flow coupled with an increase in porosity. While the flux is increased linearly, the evolution of porosity is observed to be intermittent with erosion occurring at the boundaries between low and high porosity regions. Calculating the spatial distribution of...

Recent studies of ultrasound (US) methods for targeted drug delivery and nonviral gene transfection revealed new, advantageous possibilities. These studies utilized US contrast agents, commonly stabilized microbubbles, to facilitate delivery and suggested that US delivery resulted from cell sonoporation, the formation of temporary pores in the cell membrane induced by US. Using voltage clamp te...

New data from observations of asteroid mutual perturbation events, observations of asteroid satellites, and spacecraft encounters have revolutionized our understanding of asteroid bulk density. Most asteroids appear to have bulk densities that are well below the grain density of their likely meteorite analogs. This indicates that many asteroids have significant porosity. High porosity attenuate...

Porous sol-gel silica monoliths are prepared using PMMA nanoparticles, 60 nm in diameter, as sacrificial templates. The pore-structure of the calcined pellets is investigated through nitrogen adsorption to assess the evolution of the porosity when varying the amount of porogen. The latex templated monoliths present a well defined spherical extrinsic porosity and an intrinsic microporosity due t...

OBJECTIVE To evaluate the clinical outcomes with the use of a dual-porosity expanded polytetrafluoroethylene implant for midfacial rejuvenation. DESIGN An institutional review board-approved retrospective chart review was conducted of all patients who underwent implantation with the dual-porosity expanded polytetrafluoroethylene implant between 2001 and 2005. RESULTS A total of 170 patients...

In this work we present measurements of permeability, effective porosity and tortuosity on a variety of rock samples using NMR/MRI of thermal and laser-polarized gas. Permeability and effective porosity are measured simultaneously using MRI to monitor the inflow of laser-polarized xenon into the rock core. Tortuosity is determined from measurements of the time-dependent diffusion coefficient us...

We investigated four acrylic cement preparation techniques for their effects on cement porosity: hand mixing, pressurization in a pneumatic pistol, centrifugation, and vacuum mixing. All the techniques were tested on three types of cement with different viscosity characteristics. The best results were obtained with vacuum mixing using a newly designed experimental system, yielding porosity redu...

[1] We present a model for the study of the effect of rheological hysteresis on compaction in sedimentary basins, when surface loading and unloading occurs. When compaction is slow (sedimentation rate is large and/or permeability is small), the hysteresis has little effect on the basal compaction layer, but in the more realistic case where compaction is fast (i.e., sedimentation is slow and/or ...

Results and Conclusion: The analysis results show that the cracking deflection of the prestressed, concrete beams increases with the increase in the porosity of the grouting material of the beams under different load forms. By contrast, under the same porosity grouting material, the cracking deflection of the symmetrical loads is larger than that of the uniform and concentrated loads. As the po...