The rheological response of polyisobutylene (PIB) solutions in Decalin and a related standard fluid Sl has been charac~~zed in dynamic oscillatory flow, step strain, step-shear rate and steady shear using a Rheometrics RDSII rheometer. The time dependence represented as a discrete spectrum of relaxation times and the strain dependence characterized as an exponential damping function have been p...

The dynamics of a heteropolymer chain in solution is studied in the limit of long chain length. Using functional integral representation we derive an effective equation of motion, in which the heterogeneity of the chain manifests itself as a time-dependent excluded volume effect. At the mean field level, the heteropolymer chain is therefore dynamically equivalent to a ho-mopolymer chain with bo...

Colloidal suspensions that are out of thermodynamic equilibrium undergo physical aging wherein their structure evolves to lower the free energy. In aqueous suspension of Laponite, physical aging accompanies increases of elastic and viscous moduli as a function of time. In this work, we study temporal evolution of elastic and viscous moduli at different frequencies and observe that freshly prepa...

A quasi-linear viscoelastic law with a continuous relaxation spectrum describing triaxial constitutive behaviour of heart muscle tissue is presented. The elastic response of the viscoelastic law is anisotropic, while the relaxation behaviour is assumed isotropic. The law is designed for a biphasic description (fluid-solid) of the myocardial tissue. Biaxial and uniaxial stress-strain curves from...

The present series of three consecutive papers develops a general theory for linear and fmite solid viscoelasticity. Because the most important object for nonlinear studies are rubber-like materials, the general approach is specified in a form convenient for solving problems important for many industries that involve rubber-like materials. General linear and nonlinear theories for non-isotherma...

Abstract Given a commutative semiring with compatible preorder satisfying version of the Archimedean property, asymptotic spectrum, as introduced by Strassen (J. reine angew. Math. 1988), is an essentially unique compact Hausdorff space together map from to ring continuous functions. Strassen’s theorem characterizes relaxation that asymptotically compares large powers elements up subexponential...

A weighted parallel factor analysis (W-PARAFAC) model is applied to excitation-emission matrix (EEM) fluorescence spectra of carbamate pesticides to aid with calibration in the presence of Raman scattering. Traditional PARAFAC inefficiently models the Raman scattering, resulting in prediction and calibration errors when a significant background is present. Four different weighting strategies we...

The buildup dynamics of a homogeneously broadened continuous-wave Ti:sapphire laser is experimentally investigated for the first time to our knowledge. The average output power of the laser exhibits relaxation oscillation behavior initially and approaches the steady-state value in -20 ,s. Concurrently, the longitudinal-mode spectrum evolves from a multicluster spectral distribution (tentatively...

Nuclear magnetic resonance cross-relaxation spectroscopy maps the proton solidstate NMR spectrum onto the proton water NMR signal of aqueous heterogeneous materials ( Z-3). Application of a relatively long, low-intensity RF pulse, off resonance from the water Larmor frequency but within the linewidth of the solid, partially saturates the nuclear magnetism of the solid protons. Magnetic cross re...

since the elderly population is increasing rapidly in developing countries which may decrease the physical activity and exercise and in turn could affect the elderly’s quality of life, this study aimed to investigate the effect of progressive muscle relaxation on the elderly’s quality of life in iran. in a randomized clinical trial, participants were randomly divided into intervention and contr...