Fractures matrix interaction

The rate of flow between fluids in fractures and in the rock matrix is a crucial factor for transport and reaction in fractures. For consistency with the formulation for flow between fractures and matrix used in the Yucca Mountain Project, the reactive surface area for minerals in unsaturated fractures has been related to the fracture-matrix interaction area based on a modified form of the Active Fracture Model (Liu et al., 1998 Sonnenthal el al., 2003). In this way, the wetted surface area for mineral-water reactions is consistent with that for flow and diffusion. 

Simulated and measured concentrations of conservative species in the fractures, such as chloride, are much lower than in the initial matrix pore water, indicating that fracture-matrix interaction has been negligible. However, reactive species, such as silica and potassium show significant effects of reaction with fracture-lining silicate minerals. 

Because the chemical changes are so closely tied to the TH processes and fracture-matrix interaction, modeling several chemical components provides an independent method for validating and refining TH models (e.g., the Active Fracture Model for fracture-matrix interaction and the dualpermeability method). The methodology developed for the THC model of the DST can then be applied with more certainty to long-term predictions of nuclear waste repository performance. 

Nonlinear (fynamic processes such as episodic and preferential flow, hinneling and divergence of flow pa, transient flow behavior, nonlinearity, film flow along fracture suites, intrafracture water dripping, entrapped air, fracture-matrix interaction, and pore-throat effects. 

An important consideration is the effect of filler and its degree of interaction with the polymer matrix. Under strain, a weak bond at the binder-filler interface often leads to dewetting of the binder from the solid particles to formation of voids and deterioration of mechanical properties. The primary objective is, therefore, to enhance the particle-matrix interaction or increase debond fracture energy. A most desirable property is a narrow gap between the maximum (e ) and ultimate elongation ch) on the stress-strain curve. The ratio, e , eh, may be considered as the interface efficiency, a ratio of unity implying perfect efficiency at the interfacial Junction. 

After pyrolysis, the carbon body is further densified by liquid pitch, resin impregnation, or CVD. Studies were undertaken to understand the role of the matrix, pores, and cracks, and fiber-matrix interactions in this material as it is stressed. The intent was to determine whether processing differences could alter the fracture behavior and possibly improve the physical characteristics ... 

From these results, it is clearly shown that particle size is one of the major parameters controlling the CaC03/PP composite fracture toughness. Surface treatment contributes to better particle dispersion, and also to lower particle - matrix interaction [24]. 

Although several excellent reviews analyze the effect of whisker addition on the mechanical behavior of ceramics [4, 5, 24], this review focused on the effect of phase chemistry on whisker-matrix interactions and on the relationships among the chemistry of the ceramics components, their grain morphologies, and their fracture toughnesses. 

Static fracture of the composite materials with thermoplastic matrix and unidirectional reinforced with short fibres H.L. Cox firstly treated, a case of fibre/matrix interaction, of elastic/elastic type, without taking in consideration the fibre ends. He found the fracture s determinant component is that characterised by the smallest/weakest deformation [1276]. This approximate... 

B. Beck, An Investigation of Adhesive/Adherend and Fiber/Matrix Interactions , Part B, SEM/ESCA Analysis of Fracture Surfaces , NASA Report NAGl-127, January 1983. 

A silane-coupling agent improves the suitability of jute fibers as a reinforcing material. The reaction mechanism of silane treatment of jute fibers and silane treated jute-PP composites is shown in Scheme 7.2. Silane treatment of the jute fibers increased the fiber-matrix interaction through a condensation reaction between hydrolyzed silane and hydroxyl groups of jute cellulose. During the fracture process of silanized composites, the jute fibers were broken without complete... 

Another aim of this research was to achieve a good bonding between the nanotubes and the matrix. A load transfer between them can only be achieved with a sufficiently good bonding, which should result in an improvement of the fracture mechanical properties. TEM provides a possibility of obtaining useful qualitative information concerning the nanotube-epoxy matrix interaction. 

An understanding of the mechanisms responsible for stress transfer provides the basis for prediction of the stress-strain curve of the composite and its mode of fracture (ductile vs. brittle). Such understanding and quantitative prediction may also serve as a basis for developing composites of improved performance through modification of the fibre-matrix interaction. This might be achieved, for example, through changes in the fibre shape, or treatment of the fibre surface. 

The fracture behaviour and mechanical properties of the composites are generally influenced by the interfacial structure or the fibre/matrix interactions. The nonlinear behaviour in the L-D curve and the pull-out of the fibre from the matrix without plastic deformation have demonstrated experimentally that the weak bonding between the fibres and by the van der Waals force allows the shear sliding deformation at tiie interface. The weak interaction between the... 

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