We describe a technique for improving the classification of fragmented cues for cracks. Evidence propagation on Bayesian networks represent search within the context of each cue. The algorithm was applied to a data-set of cracks, and results demonstrate that contextual classification of the cues leads to significantly improved error rates.

A fascinating class of patterns, often encountered in nature as wiggling cracks on rocks, dried out fields and tectonic plates, is produced by the fracture of solids 1. Here we report the observation and modeling of an unusual type of patterns consisting of spiral cracks within fragments of a thin layer of drying precipitate. We find that this symmetry-breaking cracking mode arises naturally no...

An important article by Ben Fine and Laurence Harris entitled 'Controversial Issues in Marxist Economic Theory' appeared in the last Socialist Register. I t has an integrated structure and is free from the Fundamentalist habit of settling debates by quoting huge chunks of Marx, in appeal to divine authority. For these and other reasons it cannot simply be brushed aside. It demands a reply, both...

The objective of this research program is to develop microwave scattering techniques for obtaining quantitative information about the characteristic dimensions of surface cracks in metals. Work carried out during the past year has emphasized experimental techniques. The use of an IF bridge and a nearfield dielectric probe to improve the sensitivity of our 100-GHz eddy-current measurement system...

We study the genesis and the selective propagation of complex crack networks induced by thermal shock or drying of brittle materials. We use a quasistatic gradient damage model to perform large-scale numerical simulations showing that the propagation of fully developed cracks follows Griffith criterion and depends only on the fracture toughness, while crack morphogenesis is driven by the materi...

We calculate elastic moduli and viscosities for media containing strongly interacting in-plane shear cracks. The cracks are randomly oriented or aligned, with equal length or a logarithmic size distribution. Our results from both a boundary element and a finite-element method suggest that the average moduli are best approximated by a differential, self-consistent model (DEM). Thus crack-tocrack...

We study pattern selection of cracks in directionally drying fractures by analyzing the experimental systems recently devised by C. Allain and L. Limat. [Phys. Rev. Lett. 74, 2981 (1995).] Proposing a simple picture of crack formation, we clarify the mechanism of how cracks array regularly and find that the interval between neighboring cracks is proportional to the 2/3 power of the cell thickne...

Abstract Previous research has indicated that the surface wave transmission (SWT) method can be used to measure the depth of a single surface-breaking crack in concrete. In this paper, the authors extend the SWT method to evaluation of distributed cracks in concrete. First, scattering field of surface waves caused by distributed cracks in concrete was investigated using numerical simulation. Se...

Fracture mechanics/technology is a key science and technology for the design and integrity assessment of the engineering structures. However, the conventional fracture mechanics has mostly targeted a limited size of cracks/defects, say of from several hundred microns to several tens of centimeters. The author and his group has tried to extend that limited size and establish a new version of fra...

Background and Aim:Root canal preparation with rotary instruments may cause dentinal cracks leading to tooth fracture. The aim of this study was to compare three different rotary systems ProTaper, RaCe and Niti Tee on formation of dentinal cracks following root canal preparation. Materials and Methods: In this experimental study, 50 extracted mandibular first molars were selected. Teeth having ...