Biomedical subjects

RS Maier

Publications and source records attributed to RS Maier.

7 recordsLinked to original sources

PubMed2000

How an anomalous cusp bifurcates in a weak-noise system

The pattern of activated trajectories in a symmetric double well system without detailed balance may contain cusps and other singularities, similar to the caustics of geometrical optics. We derive a scaling law and nonpolynomial "equations of state" that govern the bifurcation of an anomalous cusp (a cusp coinciding with the saddle) into conventional cusps. The bifurcation is reflected in the system quasipotential, much as a phase transition is reflected in the free energy of a thermodynamic system. The anomalous cusp is analogous to a nonclassical critical point. Besides showing how critical phenomena occur in noise-perturbed systems, our results extend classical catastrophe theory.

Journal Article↗

PubMed1999

Simulation of Flow in Bidisperse Sphere Packings.

Simulation methods were used to construct bidisperse, random sphere packings and to calculate fluid velocities in the pore spaces under a uniform pressure gradient. Based on these calculations, the Kozeny-Carman (KC) relation was found to hold for monodisperse and bidisperse sphere packings (r(1)/r(2) = 2.6) over a range of compositions and Reynolds numbers, using the same KC parameter value (C = 5). These results are consistent with a stronger observation about the similarity of the pore-size and flow distributions. Pore-size distributions were Gaussian for all the simulated packings, and for all bidisperse mixtures and Reynolds numbers examined, the normalized longitudinal velocity distribution collapses onto an exponential distribution when scaled by the mean velocity. Copyright 1999 Academic Press.

Journal Article↗

PubMed1996