The reliability of structures observed with electron microscope techniques represents a general problem in ultrastructure research . Obviously, every technique employed will have its limitations . Unfortunately the limitations are incompletely understood, and the eventual image obtained by electron microscopy deviates to an unknown extent from reality . The experimental approach to this problem...

2014 The phospholipid bilayer is the basic structure of biological membranes as well as a suitable model of a two-dimensional system. Defects within these bilayers are studied electron microscopically by application of the freeze fracture method Topological and non-topological defects can be distinguished The first type is analysed in terms of the homotopy theory. Two defect systems, an Abelian...

1.0 Introduction Hydraulic fracturing, the process of initiation and propagation of a crack by pumping fluid at relatively high flow rates and pressures, is one of several techniques for creating cracks in rock. Fractures in the earth's crust are desired for a variety of reasons, including enhanced oil and gas recovery, re-injection of drilling or other environmentally sensitive wastes, measure...

Hydraulic fracturing is a phenomenon in which cracks propagate through the porous medium due to high pore fluid pressure. Hydraulic fracturing appears in different engineering disciplines either as a destructive phenomenon or as a useful technique. Modeling of this phenomenon in isothermal condition requires analysis of soil deformation, crack and pore fluid pressure interactions. In this paper...

12 We report on laboratory experiments designed to investigate the effect of 13 dynamic stressing on permeability of fractured rock. Berea sandstone samples 14 were fractured in-situ under triaxial stresses of 10's of MPa, and deionized 15 water was forced through the incipient fracture under conditions of steady and 16 oscillating pore pressure. We find that dynamic stresses produced by pore 1...

This paper presents a fast method that computes deformations with fracturing of an object using a hierarchical lattice. Our method allows numerically stable computation based on so-called shape matching. During the simulation, the deformed shape of the object and the condition of fracturing are used to determine the appropriate detail level in the hierarchy of the lattices. Our method modifies ...

Computed tomographic (CT) scanning offers a simple, fast, and accurate study of complex maxillofacial trauma especially in the patient with multiple injuries. At the time of CT brain scanning, the facial bones can be scanned with only minimal extra time. High-resolution scanning provides excellent bony detail equal to or better than complex-motion tomography with the advantage of better contras...