Low density metallic foams of consistent controlled morphology offer improved unique material and mechanical properties, yet they have eluded traditional metallurgical engineering methods. A new method to produce metallic foam through a thermo-plastic expansion process has been discovered and characterized with microtomography. The new foaming process enables porosities unachievable through tra...

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...

We compare the quantitative microstructural properties of Berea Sandstone with stochastic reconstructions of the same sandstone. The comparison is based on local porosity theory. The reconstructions employ Fourier space ltering of Gaussian random elds and match the average porosity and two-point correlation function of the experimental model. Connectivity properties of the stochastic models dii...

Concentric layers of weathered materials around core-stones show the porphyritic biotite granite to experience sequential, but gradational, changes in visible features, textures and mineralogy as it transforms from ‘rock’ into ‘soil’. The start with opening-up grain boundaries micro-cracks (stage 1) followed by their dark brown staining 2) subsequent alteration (to sericite clay minerals) groun...

The present study reveals that the conventional notion that thermal contact resistance increases with porosity does not necessary hold. It is proved through a mechanistic robust model that, under specific circumstances, the porosities of two contacting bodies attain a critical value beyond which the contact resistance counter-intuitively drops. The model focuses on micro porous layers (MPLs) co...

In this work, we study, from the numerical point of view, a type III thermoelastic model with double porosity. The thermomechanical problem is written as linear system composed hyperbolic partial differential equations for displacements and two porosities, parabolic equation thermal displacement. An existence uniqueness result recalled. Then, perform its priori error analysis approximating resu...

In this paper a new macroscopic k-ε model is developed and validated for turbulent flow through porous media for a wide range of porosities. The morphology of porous media is simulated by a periodic array of square cylinders. In the first step, calculations based on microscopic v2 − f model are conducted using a Galerkin/Least-Squares finite element formulation, employing equalorder bilinear ve...

Abstract: Ball mills are used in the last stage of ore processing for grinding raw materials. Forged 70Cr2 alloy steel and Austempered Ductile Iron (ADI) balls are materials from which grinding balls are made for Sarcheshmeh Copper Plant (SCP) ball mills. In the present study wear and impact properties of these two kinds of balls have been investigated. Some balls randomly were selected as ...

UNLABELLED The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-...