We will present calculations and experiments on the effect of porosity on the shock wave attenuation, dynamic strength and fragment distribution of porous, brittle materials. These results are part of our developing theory of porosity effects on impact processes in solar system materials. We will also examine the effects of porosity on crack propagation in ice and comet analog materials. The st...

In this paper we report on a thermoelectric generator (TEG) using thermal isolation provided by a thick porous Si layer locally formed on the Si wafer and thermocouples composed of p-doped polycrystalline Si/Al. The "hot" contacts of the thermocouples lie on the porous Si layer, while the "cold" contacts lie on bulk crystalline Si. A housing was also designed and fabricated in order to transfer...

Calcium phosphate ceramics are widely used as bone substitutes since they are biocompatible and bioactive. Given that their chemical composition is close to natural bone, calcium phosphate ceramics are promising bone substitute materials in orthopaedics, maxillofacial surgery and dentistry. Hydroxyapatite (HA) and tricalcium phosphate (TCP) are the most commonly used calcium phosphates, because...

The viscosity of natural rhyolitic melt from Lipari, Aeolian Islands and melt-bubble emulsions (30^50 vol% porosity) generated from Lipari rhyolite have been measured in a concentric cylinder rheometer at temperatures and shear rates in the range 925^1150‡C and 1033^1031:2 s31, respectively, in order to better understand the dependence of emulsion shear viscosity on temperature and shear rate i...

1 ABSTRACT The continuous casting process is a widely used technique in modern steel plants. However, it is a complicated process that is not well understood. The objective of this research is to model the porosity and macrosegregation due to shrinkage related effects and solid deformation in the continuous casting of steel. Solid phase movements due to bulging and variable roll gap are modeled...

We present a series of numerically calculated plate height and flow resistance data obtained for an idealized chromatographic support mimic with variable bed porosity (0.3 </= epsilon </= 0.9), yielding a unique insight into how the main chromatographic performance parameters can be expected to vary with the external bed porosity, unbiased by any differences in molecular diffusivity or retentio...

An electrochemical etching technique has been developed that provides continuous control over the porosity of a porous silicon layer as a function of etching depth. Thin films with engineered porosity gradients, and thus a controllable gradient in the index of refraction, have been used to demonstrate broadband antireflection properties on silicon wafer and solar cell substrates. A simulation w...