Some superadditivity results in the torsion problem for multiply connected cross sections

In this note we prove strong superadditivity properties of the stress function in the elastic torsion problem for multiply connected regions. The results are extended to associated Green's functions and other domain functions.     

Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

The rate constant for the reaction of Br + O₃ → BrO + O₂ has been measured at four temperatures from 234 to 360 K by the technique of discharge flow coupled with resonance-fluorescence detection of bromine atoms. The measured rate constants obey the Arrhenius expression k = (9.45 ± 2.48) × 10^?12 exp(-659 ± 64/T) cm³/molec·sec (one standard deviation). The results are compared with two previous studies, one of which utilized the flash-photolysis–resonance-fluorescence technique and the other utilized the discharge-flow–mass-spectrometric technique. The result is also discussed from a theoretical point of view.     

Dynamic properties of materials

Summary Bentonite and stockalite clay-water systems were strained sinusoidally in shear over a wide strain range. The hysteresis loops were shown to vary from an almost straight line (elastic system) to a ferromagnetic type loop (plastic system) as the energy of oscillation was increased. The normalised dynamic modulus-strainwork plots were shown to be very similar to those observed in carbon black-elastomer and carbon black-paraffin systems.

---

Zusammenfassung Über einen weiten Dehnbereich werden Bentonit- und Stockalit-Wasser-Systeme einer sinusförmigen Dehnbeanspruchung ausgesetzt. Die Hystereseschleifen variieren mit wachsender Schwingungsenergie von einer geraden Linie (elastisches System) bis zu einer Art ferromagnetischer Schleife (plastisches System). Die normierten dynamischen Modul-Dehnungsarbeit-Diagramme sind bei den Ruß-Elastomer- und Ruß-Paraffin-System beobachteten sehr ähnlich.

---

---

Paper presented at the British Society of Rheology Conference. held at Shrivenham, from 9th–12th September, 1968.     

Configuration space Faddeev calculations

The triton ground-state wave function calculated using the Reid soft-core potential is displayed in configuration space. Both the S-state and D-state Schrödinger wave function components and the Faddeev amplitudes from which they are constructed are plotted. Specific features resulting from the tensor nature of the two-body force and from the strong short-range repulsion of the potential are discussed. Comparisons with corresponding functions generated by the Malfliet-Tjon s-wave potential model are made. Several intuitive features of the Schrödinger wave function are discussed.     

Blow-up and decay criteria for a model of chemotaxis

For a system of equations introduced by Jäger and Luckhaus (1992) [6] as a model of chemotaxis, the questions of blow-up and global existence criteria are investigated. Specifically, for a convex region, a lower bound for the blow-up time is derived if the solution blows up, and explicit criteria to ensure non-blow-up are determined.     

Some uniqueness and continuous dependence theorems for nonlinear elastodynamics in exterior domains

AMS (MOS) Nos. 73C50, 73C15; 35B30, 35M05

Uniqueness and Höolder continuous dependence upon the initial data of the null solution to the initial boundary value problem of nonlinear hyperelasticity are proved for exterior domains subject to mild asymptotic behaviour on the displacement, velocity and stress components. The strain-energy is not required to be locally sign-definite although at sufficiently large spatial distances it must be non-negative. Other limitations imposed on the strain-energy become identically satisfied upon reduction to the linear theory.     

Electrophoresis of ssDNA through nanoelectrode gaps from molecular dynamics: impact of gap width and chain length

Molecular dynamics simulations were performed to study the translocation of single-stranded (ss) DNA through the nanoscale gap between the nanoscale electrodes of a proposed genomic sequencing device. An applied electric field forces the ssDNA to move in the direction of the nanoscale gap in platinum electrodes. A series of simulations utilizing eight different nanoscale gap distances as well as seven different nucleotide chain lengths were performed to determine the impact of these variables on the overall design of the sequencing device and the translocation behavior of ssDNA. The results clearly indicate a threshold value of the gap width below which the ssDNA will readily enter and traverse the nanoscale gap. Translocation velocities obtained for various chain lengths were consistent with simulated bulk data; however, successful translocation was inconsistent, possibly related to the sample's affinity for the metal electrodes. An attempt at overcoming this barrier was made through the implementation of shaped electrodes as well as pre-threading of the ssDNA sample.