Relaxation model

The procedure we followed in adapting the relaxation model to experimental findings immediately suggests how to handle the discrepancies between the model and experiment in the case of creep ... 

DiCarlo, J. A., Creep Stress Relaxation Modeling of Polycrystalline Ceramic Fibers, NASA, 1994. 

IX. POLYMER-SOLVENT INTERACTIONS FROM THE ELECTROCHEMICALLY STIMULATED CONFORMATIONAL RELAXATION MODEL... 

Given the specific, internuclear dipole-dipole contribution terms, p,y, or the cross-relaxation terms, determined by the methods just described, internuclear distances, r , can be calculated according to Eq. 30, assuming isotropic motion in the extreme narrowing region. The values for T<.(y) can be readily estimated from carbon-13 or deuterium spin-lattice relaxation-times. For most organic molecules in solution, carbon-13 / , values conveniently provide the motional information necessary, and, hence, the type of relaxation model to be used, for a pertinent description of molecular reorientations. A prerequisite to this treatment is the assumption that interproton vectors and C- H vectors are characterized by the same rotational correlation-time. For rotational isotropic motion, internuclear distances can be compared according to... 

Two different approaches have been followed to calculate the lineshapes within a relaxation model. According to a phenomenological approach based on the modified Bloch equations [154, 155], the intensity distribution of the theoretical Mossbauer spectrum may be written as [156] ... 

Fig. 23. Mossbauer spectra of Fe(J-mph)NO between 84 and 319 K. Solid lines result from a fit by a two-state relaxation model based on the stochastic theory of lineshapes. According to Ref. [164]...

Fig. 37. Fe-M6ssbauer spectra of [Fe(mtz)g](PF6)2 at 213 and 243 K. Solid lines represent spectra calculated on the basis of a relaxation model inclusive of texture. According to Ref [174]...

Table 15. Rate constants Ichl fot the spin-state transition in [Fe(mtz)6](PF5)2 derived on the basis of a relaxation model ...

Fig. 6.5 Mossbauer spectra of NH4Fe(S04)2-12H20 at 4.2 K and with the indicated magnetic fields applied parallel to the y-ray direction. The lines indicate fits in accordance with a theoretical relaxation model [19, 29]. The bar diagrams indicate the theoretical line positions in the case of infinitely fast relaxation. (Adapted from [29] copyright 1973 by Springer-Verlag)...

Fig. 6.8 Mossbauer spectra of deoxy-myoglobin, obtained in applied fields of 2 T (left) and 6.2 T (right) at temperatures of 4.2, 10, 15, 20, 30 and 50 K (from bottom to top). The solid lines were calculated using a relaxation model. (Reprinted from [34] copyright 1994 by Springer-Verlag)...

Other models have also been proposed, such as a relaxation model by Bauer et al. (1978) and a mechanistic model by Re ocreaux (1977). The readers are referred to these references for details. 

Figure 15 shows that the RR quantum direct relaxation model fits successfully the RY semiclassical relaxation one. Other computations that are not given here lead to the conclusion that such a result is generally met when ... 

Fig. 2 The Mossbauer spectra obtained during the initial heating, left, and initial cooling, right, of [Fe(HB(pz)3)2] and fitted with a relaxation model. Data obtained in part from [30]...

Upon cooling, see Fig. 2, the observed Mossbauer spectra of [Fe(HB (pz)3)2] are very different from those observed upon the initial heating. Indeed, the dramatic difference is immediately apparent through a comparison of the 380 and 400 K spectra shown in Fig. 2 for the initial heating and initial cooling. The spectra shown in this figure are very typical of rapid relaxation on the Mossbauer effect time scale between the high-spin and the low-spin iron(II) states. As a consequence, all of the Mossbauer spectra of [Fe(HB(pz)3)2] obtained above 295 K were fitted with a relaxation model de-... 

A transported PDF extension of the Hamelet model can be derived in a similar manner using the Lagrangian spectral relaxation model (Fox 1999) for the joint scalar dissipation rate. 

The spectral relaxation model of the scalar dissipation rate in homogeneous turbulence. Physics of Fluids 7, 1082-1094. 

III. Test of the Adam-Gibbs Relaxation Model for Glass Formers Based on the Heat-Capacity Data of 1,3,5-Tri-a-Naphthylbenzene. 

Figure 9.15 Dielectric function of water at room temperature calculated from the Debye relaxation model with r = 0.8 X 10 11 sec, eQcl = 77.5, and e0l, = 5.27. Data were obtained from three sources Grant et al. (1957), Cook (1952), and Lane and Saxton (1952).

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