Recently singular solutions have been discovered in purely elongational flows of visco-elastic fluids. We surmise that these solutions are the mathematical structures underlying the so-called birefringent strands seen experimentally. In order to facilitate future experimental studies of these we derive a number of asymptotic results for the scaling of the width and extension of the near-singula...

The FENE dumbbell model consists of the incompressible NavierStokes equation for the solvent and the Fokker-Planck equation for the polymer distribution. In such a model, the polymer elongation cannot exceed a limit √ b which yields all interesting features of solutions near this limit. This work is concerned with the sharpness of boundary conditions in terms of the elongation parameter b. Thro...

The effect of stress diffusivity is examined in both the Oldroyd-B and FENE-P models of a viscoelastic fluid in the low Reynolds (Stokes) limit for a 2D periodic time-dependent flow. A local analytic solution can be obtained when assuming a flow of the form u =Wi (x, y), whereWi is the Weissenberg number. In this case the width of the birefringent strand of the polymer stress scales with the ad...

We consider a dilute suspension of dumbbells joined by finitely extendible nonlinear elastic connector evolving under the classical Warner potential , . The solvent consideration is modelled compressible Navier–Stokes system defined on torus with d = 2, 3 coupled Fokker–Planck equation (Kolmogorov forward equation) for probability density function dumbbell configuration. prove existence unique ...

Senile plaques (SPs) and neurofibrillary tangles (NFTs) are hallmark pathologies accompanying the neurodegeneration involved in Alzheimer's disease (AD), for which beta-amyloid (Abeta) peptide is a major constituent of SPs. Our laboratories previously developed the hydrophobic, fluorescent molecular-imaging probe 2-(1-(6-[(2-[(18)F]fluoroethyl)(methyl)amino]-2-naphthyl)ethylidene)malononitrile ...

A thin filament model is used to analyze the stability of a viscoelastic thread subject to uniaxial stretching. Linear stability analysis is carried out for a number of different constitutive models, namely the Johnson–Segalman, Giesekus, Phan–Thien Tanner, and FENE–CR. Our analysis shows that stability is controlled by the competing effects of surface tension which is destabilizing and axial n...

We have implemented the log-conformation method for two-dimensional viscoelastic flow in COMSOL, a commercial high-level finite element package. The code is verified for an Oldroyd-B fluid flowing past a confined cylinder. We are also able to describe the well-known bistability of the viscoelastic flow in a crossslot geometry for a FENE-CR fluid, and we describe the changes required for perform...

Fengycin, a lipopeptidic antibiotic, is synthesized nonribosomally by five fengycin synthetases (FenC, FenD, FenE, FenA, and FenB) in Bacillus subtilis F29-3. This work demonstrates that these fengycin synthetases interlock to form a chain, which coils into a 14.5-nm structure. In this chain, fengycin synthetases are linked in the order FenC-FenD-FenE-FenA-FenB by interactions between the C-ter...