Thomsen parameter

In sediments, lamination creates macroscopic anisotropy, which results from an alternating change of the elastic properties of thin layers the effect of the intrinsic or bulk layer anisotropy, particularly for the shale/clay, and fracturing, can be superimposed. Table 6.13 shows some values for Thomsen parameters for sedimentary rocks. 

TABLE 6.13 Values for Thomsen Parameters for Some Sedimentary Rocks... 

In a systematic study, Wang (2002) published experimental results of the elastic properties (all five tensor components) and Thomsen parameters on a total... 

The calculated tensor elements allow studies of anisotropy as well as of the velocity ratio Vp/Vs- Figure 6.36 gives an example of forward calculation for the shear wave anisotropy (Thomsen parameter y) as a function of fracture porosity and aspect ratio. Clearly expressed is the strong influence of aspect ratio on anisotropy. Such studies can help to interpret and understand shear wave splitting effects. 

FIGURE 6.36 Hudson s model—calculated shear wave anisotropy (Thomsen parameter y) as a function of porosity and aspect ratio a (curve parameter). Input parameters are for the solid material (calcite) ls = 54 GPa, /is=31 GPa, and for the fluid (water) fi = 2.2 GPa. 

Thomsen, M.B., Matz, J., Volders, P.G. and Vos, M.A. (2006) Assessing the proarrhythmic potential of drugs current status of models and surrogate parameters of torsades de pointes arrhythmias. Pharmacology el Therapeutics, 112, 150-170. 

J. S. Thomsen, Li. Mosekilde, and E. Mosekilde Quantification of remodeling parameter sensitivity - assessed by a computer simulation model, Bone 1996, 19 505-511. 

K. Thomsen, Aqueous electrolytes model parameters and process simulation, Ph.D. Thesis, Department of Chemical Engineering, Technical University of Denmark, 1997,... 

Sorensen PB, Mogensen BB, Carlsen L, Thomsen M (2000) The influence of partial order ranking from input parameter uncertainty. Definition of a robustness parameter. Chemosphere 41 595-601... 

A number of different values for the A and B parameters have been proposed in the literature, as recently reviewed by Reich, Thomsen, and Maultzsch (17). We typically use A = 223.5 cm /nm and B= 12.5 cm (18), as illustrated in Table 13.1. When the sample contains bundles, accurate estimates can only be obtained if intertube physical interactions are considered, since a significant upshift of the RBM is observed for nanotubes in bundles, with respect to isolated nanotubes (19). 

Thomsen, L.L., Sargent, J.M, Williamson, C.J., and Elgie, A.W. (1998). Nitric oxide synthase activity in fresh cells from ovarian tumour tissue relationship of enzyme activity with clinical parameters of patients with ovarian cancer. Biochem. Pharmacol. 56, 1365-1370. 

For the transverse isotropic material, Thomsen (1986) defined the following parameters ... 

TABLE 6.14 Elastic Stiffness Components and Anisotropy Parameters for Jurassic Shale Thomsen s Confinine Elastic Stiffness (GPa) Parameters ... 

For Jurassic shale (total clay 57-59 vol.%), Hornby (1995a,b) determined the elastic stiffness components and Thomsen s parameters as a function of the confining pressure (Table 6.14). Increasing pressure results in a moderate decrease of compressional anisotropy (c) and a stronger decrease of shear anisotropy (y). 

TABLE 6.15 Elastic Stiffness, Thomsen s Parameters, and Clay Content from Woodford Shale... 

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