Griffith approach

For a weaker (stronger) axial CF the excited 4Tig term splits into a 4A2g and 4 g pair, and we need to return to the Weissbluth-Griffith approach. The ZFS interaction matrix of the form... 

Continuing in this line of thought, Williams (34) has suggested a useful formulation of the Griffith approach. He suggested viewing Yc as a compilation of effects. That is. 

Finally it is worth noting that the Griffith approach, Eq. (11.10), can be reconciled with Eq. (11.2) by assuming that p is on the order of lOro, where tq is the equilibrium interionic distance (see Prob. 11.3). In other words, the Griffith approach implicitly assumes that the flaws are atomically sharp, a fact that must be borne in mind when one is experimentally determining ATp. for a material. 

The cohesive tensile stress (ss T/10) is smaller than the cohesive strength in shear, in which case the solid can sustain a sharp crack and the Griffith approach is valid. 

An alternative way of expressing the Griffith approach is to equate the energy differential of the mechanical terms with that associated with the creation of new surface, i.e.. 

In the Irwin approach, as with the Griffith approach, strength is found to depend on a combination of a material property (intrinsic) and a flaw size (extrinsic). In the linear elastic fracture mechanics approach, however, the material property is T or R and it has a component that depends on the microstructure of the material. Thus, if the mechanisms that increase T for a material can be identified, an approach is available to increase the reliability of brittle materials. It is this philosophy that has been a major driving force in the recent production of ceramics with higher strengths and toughnesses than had previously been considered possible. 

In the Griffith approach, the failure condition (uniaxial tension) is defined in terms of the energy [/ of a system and the crack size c. Write down a mathematical expression for this failure criterion. 

Thi.s alternative view is consistent with the notion that the surface-energy term in the Griffith approach [12] is replaced by a term incorporating the surface energy and the energy dissipated by plastic deformation [15]. 

Griffith derived a similar equation using an energy balance approach, equating stored energy with the energy required for crack propagation ... 

Griffiths B (1992) Scaling-up of animal cell cultures. In Freshney RI (ed) Animal cell culture A practical approach. Oxford University Press, Oxford, p 47... 

Mewhinney JA, Griffith WC, Muggenburg BA. 1980. Proposed retention model for human inhalation exposure to 241Am02. In International Radiation Protection Society, ed. Radiation protection A systemic approach to safety Proceedings of the 5th Congress of the International Radiation Protection Society, Jerusalem, March 1980. New York Pergamon Press, 615-618. 

Hsu and Graham (1961) took into consideration the bubble shape and incorporated the thermal boundary-layer thickness, 8, into their equation, thus making the bubble growth rate a function of 8. Han and Griffith (1965b) took an approach similar to that of Hsu and Graham with more elaboration, and dealt with the constant-wall-temperature case. Their equation is... 

Norton KL, Lange AJ, Griffiths PR. A unified approach to the chromatography-FTIR interface GC-FTIR, SFC-FTIR and HPLC-FTIR with subnanogram detection limits. HRC-J. High Resolut. Chromatogr. 1991 14 225-229. 

If animal testing is required, a full-scale Draize test may not be necessary given the background established in the beginning of the tier approach. For instance, the compound could be tested in a single sentinel animal to obtain confirmation of in vitro data. In addition, other modifications could be used, such as the administration of appropriate anesthetics to the test animals, or the use of the low-volume Draize modification (Falahee et al., 1982 Freeberg et al., 1984 Griffith, 1987). 

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