Seismic curvature gradient is a useful third-order geometric attribute that has demonstrated its value for subsurface structure analysis, especially fracture detection in fractured reservoirs. However, most recent efforts have been primarily focused on predicting fracture intensity by this attribute; and little has been published on applying it to predict most likely fracture orientation, which...

Hip fractures may result in severe morbidity and mortality among elderly patients. Many risk factors for hip fracture have been identified, including cognitive impairment. The authors used the Mini-Mental State Examination (MMSE), a screen test for cognitive impairment, as the study material for their hip fracture survey. The authors hypothesized that certain subdomains would have a strong asso...

Azimuthally-dependent P-wave AVO (amplitude variation with offset) responses can be related to open fracture orientation and have been suggested as a geophysical tool to identify fracture orientation in fractured oil and gas reservoirs. A field experiment recently conducted over a fractured reservoir in the Barinas Basin (Venezuela) provides data for an excellent test of this approach. Three li...

The submicroscopic morphology of magnesian calcite skeletal units of echinoids, revealed by scanning electron microscopy, was compared with crystal orientation data obtained by x-ray methods and with macroscopic morphology. The Perischoechinoidea and the Euechinoidea differ with regard to the shapes of their trabeculae. Nearly all plates and spines are single crystals. A variety of diJfferent d...

Toughening mechanisms based on the presence of collagen fibrils have long been proposed for mineralized biological tissues like bone and dentin; however, no direct evidence for their precise role has ever been provided. Furthermore, although the anisotropy of mechanical properties of dentin with respect to orientation has been suggested in the literature, accurate measurements to support the ef...

The strength and fracture behavior of Saxidomus purpuratus shells were investigated and correlated with the structure. The shells show a crossed lamellar structure in the inner and middle layers and a fibrous/blocky and porous structure composed of nanoscaled particulates (~100 nm diameter) in the outer layer. It was found that the flexure strength and fracture mode are a function of lamellar o...

Composite materials have important assets compared to traditional materials. They bring many functional advantages: lightness, mechanical resistance and chemical, etc. In the present study we examine the effect of a circular central notch and a precrack on the tensile fracture of two woven composite materials. The tensile tests were applied to a standardized specimen, notched and a precarcked (...

Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and pr...

This research focuses on fracture networks in sedimentary rocks within the Umbria-Marche fold-and-thrust belt in the Northern Apennines, Italy. The aim of this research is twofold, namely to correlate the geometry of fracture networks with tectonic position and lithology and to correlate the orientation of fracture networks with the origination of a fold-and-thrust structure. The fold-and-thrus...