Materials are often characterized in terms of their toughness, though more than one definition of toughness exists. Likely the most widely recognized means of defining material toughness, denoted here as τ, is by the area under the stress strain curve from a tensile test. Another important feature describing the nature of materials is that property known as brittleness, which has for a long tim...

Chang 8 oil deposit, developed in Hohe and Jihe oil fields at the southern Yi-Shan Slop of Ordos Basin, is regarded as a kind of typical sand reservoir formation with super-low porosity, poor permeability, strong anisotropy as well as locally natural faults and fractures. The previous studies believed that matrix reservoir has a good permeability, whereas fracture reservoir has a reverse manner...

A new experimental method aiming to the characterization of self-affine rough surfaces is presented. Based on a three dimensional reconstruction of the relief from stereo pairs obtained with a scanning electron microscope, it allows a non-destructive quantitative analysis of fracture surfaces, with a xy and z resolution only slightly lower than the original images. The roughness index of the fr...

We correlate the experimentally measured fracture toughness of 24 metals and ceramics to their quantum mechanically calculated brittleness parameter. The brittleness parameter is defined as the ratio of the elastic energy density needed to spontaneously break bonds in shear versus in tension, and is a primitive-cell property. Under 300 GPa hydrostatic pressure, the model predicts that diamond h...

Abstract Brittleness is a crucial parameter of rock mass and the key indicator in engineerings, such as rockburst prediction, tunnelling machine borehole drilling, hydraulic fracturing. To solve problem using present brittleness indexes, existing indexes were firstly summarised this paper. Then, index (BL), which considers ratio stress drop rate increase peak stress, was proposed. This new has ...

The term software architecture (SA) intuitively denotes the high level structures of a software system. It can be defined as the set of structures needed to reason about the software system, which comprise the software components and connectors, their relations and properties. Nowadays SA has become an important factor in the process of software development and the researches mainly focus on th...

Software flexibility is one of the properties that indicate if the software is easy to change. Flexible software can easily adapt to user requirement and/or environment changes during the software development period or after the software is deployed. In this paper, we introduce two new concepts, flexible change and FleXible Point( FXP). Associated with the flexible point, a set of flexibility i...