Structural Properties of Two-Dimensional Polymers

We present structural properties of two-dimensional polymers as far as they can be described by percolation theory. The percolation threshold, critical exponents and fractal dimensions of clusters are determined by computer simulation and compared to the results of percolation theory. We also describe the dependence of the typical cluster structures on the reaction rate.Comment: 7 pages, LaTeX with RevTeX and epsf styles and PostScript figures included (uuencoded shell archive), TVP-93051

Exponential distributions of collective flow-event properties in viscous liquid dynamics

We study the statistics of flow events in the inherent dynamics in supercooled two- and three-dimensional binary Lennard-Jones liquids. Distributions of changes of the collective quantities energy, pressure and shear stress become exponential at low temperatures, as does that of the event "size" $S\equiv\sum {d_i}^2$. We show how the $S$-distribution controls the others, while itself following from exponential tails in the distributions of (1) single particle displacements $d$, involving a Lindemann-like length $d_L$ and (2) the number of active particles (with $d>d_L$).Comment: Accepter version (PRL

Two-way coupling of FENE dumbbells with a turbulent shear flow

We present numerical studies for finitely extensible nonlinear elastic (FENE) dumbbells which are dispersed in a turbulent plane shear flow at moderate Reynolds number. The polymer ensemble is described on the mesoscopic level by a set of stochastic ordinary differential equations with Brownian noise. The dynamics of the Newtonian solvent is determined by the Navier-Stokes equations. Momentum transfer of the dumbbells with the solvent is implemented by an additional volume forcing term in the Navier-Stokes equations, such that both components of the resulting viscoelastic fluid are connected by a two-way coupling. The dynamics of the dumbbells is given then by Newton's second law of motion including small inertia effects. We investigate the dynamics of the flow for different degrees of dumbbell elasticity and inertia, as given by Weissenberg and Stokes numbers, respectively. For the parameters accessible in our study, the magnitude of the feedback of the polymers on the macroscopic properties of turbulence remains small as quantified by the global energy budget and the Reynolds stresses. A reduction of the turbulent drag by up to 20% is observed for the larger particle inertia. The angular statistics of the dumbbells shows an increasing alignment with the mean flow direction for both, increasing elasticity and inertia. This goes in line with a growing asymmetry of the probability density function of the transverse derivative of the streamwise turbulent velocity component. We find that dumbbells get stretched referentially in regions where vortex stretching or bi-axial strain dominate the local dynamics and topology of the velocity gradient tensor.Comment: 20 pages, 10 Postscript figures (Figures 5 and 10 in reduced quality

Hostile mood and social strain during daily life: A test of the transactional model.

Hostility is a multidimensional construct related to cardiovascular (CV) disease risk. Daily hostile mood and social interactions may precipitate stress-related CV responses in hostile individuals. Purpose: Determine whether trait cognitive hostility best predicts daily hostile mood and social interactions relative to other trait hostility factors and explore the temporal links between these daily measure

Grand-canonical solution of semiflexible self-avoiding trails on the Bethe lattice

11 pages, 7 figures11 pages, 7 figures11 pages, 7 figure

Tuning of emission color for blue dendrimer blend light-emitting diodes

Published versio

Portfolio Vol. I N 2

Wiley, Thomas R. In the Cathedral, Mexico City . Picture. 2. Whitehead, Richard Jr. Izzy was a Lady, After All . Prose. 3. Beckham, Adela. Rain on a March morning . Poem. 6. Beckham, Adela. Heaven . Poem. 6. Deane, Dorothy. Temptation . Poem. 6. Kellogg, Elizabeth. Gruess Dich Gott . Prose. 7. Nadel, Norman. The Duchess . Poem. 8. Dick, Pewilla. The Sligo Fisherman . Prose. 9. Deane, Dorothy. Against the Winter . Poem 12. Flory, Doris Jean. A problem . Poem 12. Travis, Paul Bough. My First View of the Congo Forest . Picture. 13. Bellows, George. Stag at Sharkey\u27s . Picture. 13. B.C.W. Aspiration . Poem. 14. Stewart, John. On Record . Prose 14. Sweitzer, Harry J. Playing Around . Prose. 15. Ellsberg, Edward. Book Parade: Hell on Ice . Prose. 15. B.C.W. End of Winter . Poem. 16. Wiley, Thomas R. End of Winter . Picture. 16. Deeter, Robert. Television, How, Where, and When . Prose. 17. Brush, Jane. Love A La Mode . Poem. 20. Brush, Jane. Radio! . Poem. 20. Brush, Jane. Backward Glance . Poem. 20. Brush, Jane. Homo Paradoxus . Poem. 20. Brush, Jane. The Sardonic Slant . Poem. 20. Brush, Jane. Baths . Prose. 20. Wilson, Gordon. Brushword . Cartoon. 20