The dynamics of elastocapillary thinning in high molecular weight polymer solutions are reexamined using high-speed digital video microscopy. At long times, the evolution of the viscoelastic thread deviates from self-similar exponential decay and the competition of elastic, capillary, and inertial forces leads to the formation of a periodic array of beads connected by axially uniform ligaments....

The present note deals with large time properties of the Lagrangian trajectories of a turbulent ow in IR 2 and IR 3. We assume that the ow is driven by an incompressible time-dependent random velocity eld with Gaussian statistics. We also assume that the eld is homogeneous in space and stationary and Markovian in time. Such velocity elds can be viewed as (possibly innnite dimensional) Ornstein-...

In this paper, we perform a careful numerical study of nearly singular solutions of the 3D incompressible Euler equations with smooth initial data. We consider the interaction of two perturbed antiparallel vortex tubes which was previously investigated by Kerr in [14, 17]. In our numerical study, we use both the pseudo-spectral method with the 2/3 dealiasing rule and the pseudo-spectral method ...

Electrospun polymer jets are imaged for the first time at an ultra-high rate of 10,000 frames per second, investigating the process dynamics, and the instability propagation velocity and displacement in space. The polymer concentration, applied voltage bias and needle-collector distance are systematically varied, and their influence on the instability propagation velocity and on the jet angular...

We analyze the collective modes of high-temperature QCD in the case when there is an anisotropy in the momentum-space distribution function for the gluons. We perform a tensor decomposition of the gluon self-energy and solve the dispersion relations for both stable and unstable modes. Results are presented for a class of anisotropic distribution functions which can be obtained by stretching or ...

A picosecond time-resolved IR-UV pump-probe spectroscopic study was carried out for the intramolecular vibrational energy redistribution of the OH/OD stretching vibration of isolated phenol and its isotopomers in supersonic beams. The time evolution due to IVR showed a significant isotope effect; the OH stretch vibration showed a single exponential decay and its lifetime is greatly lengthened u...

The recently developed single molecule force spectroscopy enables the detailed study of the mechanisms of protein unfolding and refolding under a stretching force. It has revealed many signatures of complexity of the underlying energy landscape that were previously overlooked in bulk experiments. For example, the broad distribution of unfolding times of the protein ubiquitin has been suggestive...

A recently developed methodology for the calculation of the dynamic heat capacity from simulation is applied to the east Ising model. Results show stretched exponential relaxation with the stretching exponent, beta, decreasing with decreasing temperature. For low temperatures, the logarithm of the relaxation time is approximately proportional to the inverse of the temperature squared, which is ...

The origin and sustenance of large scale galactic magnetic fields has been a long standing and controversial astrophysical problem. Here an alternative to the “standard” α−Ω mean field dynamo and primordial theories is pursued. The steady supply of supernovae induced turbulence exponentiates the total field energy, providing a significant seed mean field that can be linearly stretched by shear....

Differential dynamic microscopy (DDM) was used to investigate the diffusive dynamics of nanoparticles of diameter 200-400 nm that were strongly confined in a periodic square array of cylindrical nanoposts. The minimum distance between posts was 1.3-5 times the diameter of the nanoparticles. The image structure functions obtained from the DDM analysis were isotropic and could be fit by a stretch...