the effect of mixing on rheological behavior of 6% wt epoxy-clay nanocomposites was studied. the mixing processes were carried out by low shear mixer, homogenizer and ultrasonic and combination of different mixing techniques at medium and maximum power. all these methods led to intercalated structure. the xrd results showed that the ultrasonic has the best effect on dispersion while a low shear...

the molecular weight distribution of 4 commercial isotactic polypropylene (ipp) samples was estimated using rheological data. the dynamic moduli data, obtained from rheological measurements in linear viscoelastic region was used for calculation of relaxation time spectrum, h(τ) and then shear relaxation modulus, g(t). finally, applying thimm kernel function and relaxation modulus data in genera...

Efficient numerical finite-element analysis of creeping concrete structures requires the use of Kelvin or Maxwell chain models, which are most conveniently identified from a continuous retardation or relaxation spectrum, the spectrum in turn being determined from the given compliance or relaxation function. The method of doing that within the context of solidification theory for creep with agin...

The macroscopic viscoelastic behavior of collagen gel was studied through relaxation time distribution spectrum obtained from stress relaxation tests and viscoelastic constitutive modeling. Biaxial stress relaxation tests were performed to characterize the viscoelastic behavior of collagen gel crosslinked with Genipin solution. Relaxation time distribution spectrum was obtained from the stress ...

Historically, it has always been understood that the relaxation spectra of linear viscoelastic materials are continuous. Nevertheless, because of their ease of implementation computationally, delta function recovery methods have been and continue to be important, even though they do not generate continuous approximations. Derivative based recovery techniques were popular in the precomputer days...

We describe the spectra and pseudospectra of continuous time and discrete time waveform relaxation operators. Since the spectrum of the finite-interval waveform relaxation operator is only a singleton, the spectrum of the infinite-interval operator is typically used to describe the behavior of waveform relaxation algorithms. Here, we show that the pseudospectrum is a more useful tool for analyz...

We have obtained the continuous radio frequency spectrum of water molecule relaxation using carbon nanotubes (CNT) as a high-speed nanoprobe. Three sets of characteristic time scales are clearly identified. Two sets are attributed to the electric-field-driven polarization of water molecules bound to CNTs and the collective relaxation of water layers in the vicinity of CNTs, respectively. The th...

Two-dimensional vector fields undergoing a Hopf bifurcation are studied in a Liouville-equation approach. The Liouville equation rules the time evolution of statistical ensembles of trajectories issued from random initial conditions, but evolving under the deterministic dynamics. The time evolution of the probability densities of such statistical ensembles can be decomposed in terms of the spec...