We study the average velocity of crack fronts during stable interfacial fracture experiments in a heterogeneous quasibrittle material under constant loading rates and during long relaxation tests. The transparency of the material (polymethylmethacrylate) allows continuous tracking of the front position and relation of its evolution to the energy release rate. Despite significant velocity fluctu...

In this paper the determination of the spacewise dependent material property coefficients and the function solution in both steady and unsteady diffusion problems are analysed. For a one-dimensional quasi-heterogeneous material with square-root harmonic conductivity it is shown that a single measurement of the conductivity and the flux on the boundary is sufficient to determine uniquely the unk...

We explore the advantage of using genetic algorithms for the automated design of a small satellite passive thermal control. The control law is a layout of heterogeneous material patches covering the satellite surface. We tested our candidate material patch solutions with a finite element method simulation of the satellite thermal conditions during direct sun light orbit. We found that the metho...

The determination of the hydraulic properties of heterogeneous soils or porous media remains challenging. In the present study, we focus on determining the effective properties of heterogeneous porous media at the Darcy scale with an analysis of their uncertainties. Preliminary, experimental measurements of the hydraulic properties of each component of the heterogeneous medium are obtained. The...

This research presents temperature distribution and thermal strain of functionally graded material cylinders with varying thickness and temperature-dependency properties that are subjected to heat fluxes in their inner and outer layers. The heterogeneous distribution of properties is modeled as a power function. Using first-order temperature theory and the energy method, governing equations are...

in the present study, the synthesis of diethylene triamine supported on cellulose biopolymer as a biodegradable solid basic heterogeneous catalyst was suggested. then, the applicability of the synthesized catalyst cellulose bonded n-propyl diethylene triamine (cbpdeta) was tested for the synthesis of oxindole derivatives, an important class of potentially bioactive compounds. a various series o...

the aim of this study is to investigate the nucleation of new grains by necklacing mechanism during dynamic recrystallization (drx). the material used is 316 stainless steel. in order to modeling the deformation behavior during hot rolling, one-hit compression tests were performed at temperature range of 950-1100 °c with strain rates of 0.01-1s-1. the result shows that at the temperature of 100...

In the existing finite element head models (FEHMs) that are constructed from medical images, head tissues are usually segmented into a number of components according to the interior anatomical structure of the head. Each component is represented by a homogenous material model. There are a number of disadvantages in the segmentation-based finite element head models. Therefore, we developed a non...

Stochastic analysis of random heterogeneous media provides information of significance only if realistic input models of the topology and material property variations are used. This work introduces a framework to construct such input stochastic models for the topology, thermal diffusivity and permeability variations in heterogeneous media using a data-driven strategy. Given a set of microstruct...

The as-grown surfaces of 6H SiC seed crystals grown by the Lely method have been characterized by visible light microscopy and atomic force microscopy. The surfaces were then used to seed the sublimation growth of SiC at 2300'C, in 650 torr of Ar, with a gradient of 8 °C/cm. Repeated observations of the seed surface structure after predetermined intervals in the growth reactor demonstrated that...