Compliance dynamic

Williams and Ferryf measured the dynamic compliance of poly(methyl acrylate) at a number of temperatures. Curves measured at various temperatures were shifted to construct a master curve at 25°C, and the following shift factors were obtained ... 

Static compliance is usually higher than dynamic compliance because there is time for volume and pressure equilibration between the lungs and the measuring system. The measured volume tends to increase and the measured pressure tends to decrease, both of which act to increase compliance. Compliance is often plotted on a pressure-volume graph. 

Where D" is the loss compliance or the out-of-phase component of the dynamic compliance. The rate is given by... 

A summary of analytic expressions obtained in this manner for all the viscoelastic functions is presented in Table 4 and 5 for the linear and cubic arrays. The well-known phenomenological analogy (8) between dynamic compliance and dielectric permittivity allows the formal use of Eqs. (T 5), (T 6), and (T 11), (T 12) for the dielectric constant, e (co), and loss, e"(co), of the linear and cubic arrays, respectively (see Table 6). The derivations of these equations are elaborated in the next section and certain molecular weight trends are discussed. 

Explication of the Tables and Discussion of Molecular Weight Trends Linear Array. The reduced dynamic compliance of an assembly of linear macromolecules is, according to theory (11),... 

FIG. 13.92 Birefringence An as a function of the dynamic compliance E 1 = 5 for various polyester tire yarns. 

It should be pointed out that m is positive, and its value lies in the range 0 < m < 1. Following analogous procedures, the retardation and relaxation spectra can be obtained from dynamic relaxation and dynamic compliance functions, respectively. The pertinent equations can be found in Ref. 1. 

The inversion of transform (5.3.2) and the determination of L (t ), when the analytical dependence Y j is known, have been considered previouslyThe results were based on the well-known inversion equations of Kirkwood and Fuoss (see also Ref. ) establishing a relationship between L(t ) and the corresponding dynamic compliance function Z(ico). Indeed, the reduced complex dynamic compliance corresponding to a distribution L j) is given by... 

The proposed method of data treatment has two advantages (1) It allows assessment of the status of blend miscibility In the melt, and (11) It permits computation of any linear viscoelastic function from a single frequency scan. Once the numerical values of Equation 20 or Equation 21 parameters are established Che relaxation spectrum as well as all linear viscoelastic functions of the material are known. Since there Is a direct relation between the relaxation and Che retardation time spectra, one can compute from Hq(o)) the stress growth function, creep compliance, complex dynamic compliances, etc. 

In followup experiments, the pulmonary effects of JP-8 inhalation in mice were evaluated (Robledo and Witten 1998 Robledo et al. 2000 Wang et al. 2001). Groups of C57BL/6 and B6.A.D. (Ahrd/Nats knockout) mice were exposed 1 hr/day for 7 days to ambient air or aerosolized JP-8 at 0-118 mg/ m3. JP-8 vapor was also present however, the concentration of the vapor in the exposure atmosphere was not reported. Exposure had no effect on dynamic compliance or resistance. Lung epithelial permeability, as determined with 99mTcDTPA, was affected in C57BL/6 mice exposed at 50 and 113... 

Figure 3-6. Frequency dependence of the complex dynamic compliance for the Voigt model.

When two compartments have different time constants due to differences in resistance or compliance, gas can be flowing out of one at the same time as it is flowing into the other. This pendelluft phenomenon reduces effective tidal volume results in frequency dependence of dynamic compliance and resistance measurements, and again makes prediction of aerosol distribution in the presence of disease highly complex (269) (Fig. 18). 

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