Evidence for an elongated (>60 ion skin depths) electron diffusion region during fast magnetic reconnection

Observations of an extremely elongated electron diffusion region occurring during fast reconnection are presented. Cluster spacecraft in situ observations of an expanding reconnection exhaust reveal a broad current layer ( approximately 10 ion skin depths thick) supporting the reversal of the reconnecting magnetic field together with an intense current embedded at the center that is due to a super-Alfvénic electron outflow jet with transverse scale of approximately 9 electron skin depths. The electron jet extends at least 60 ion skin depths downstream from the X-line.     

Stability of a stationary steam-water front in a porous medium

The instability of a plane front between two phases of the same fluid (steam and water) in a porous medium is considered. The configuration is taken to be initially stationary with the more dense phase overlying the less dense phase. The frontal region is assumed sharp, so that macroscopic boundary conditions can be utilized. This assumption precludes the existence of dispersion instabilities. The stabilizing influence of phrase transition as well as the implication of different macroscopic pressure boundary conditions on the stability of the front are discussed and illustrated.     

The effect of volume relaxation on elastohydrodynamic lubrication

In elastohydrodynamic lubrication (EHD) three important non-Newtonian effects arise. These are volume viscoelasticity, shear viscoelasticity, and the variation of viscosity with shear rate. All these effects tend to decrease the shear stress or traction.In this paper the effect of volume relaxation of EHD is examined using experimental viscosity data obtained in a simple viscometric flow. It is shown that the viscosity of a fluid during EHD is unlikely to reach its equilibrium value. Approximations to the viscosity as a function of time lead to the conclusion that volume and shear viscoelasticity have effects which are of the same order of magnitude and will be difficult to separate except by an exact knowledge of the shear rate and pressure profiles.     

Applications of d.c. argon plasma emission spectroscopy to saline waters: a study of enhancement effects

A commercially available d.c. argon plasma emission spectrometer was used to determine transition metals (3d and 4d) and also Be in salt and brackish water. The effects of salinity on the enhancement of emission intensities of the analyte lines were studied using an empirical approach combined with statistical analysis. One set of experiments deals with the effects of trace metal concentration and salinity on the relative emission intensities of 14 elements using a completely randomized experimental design, i.e. the sequence in which the 48 treatment combinations (12 levels of salinity and 4 levels of metal concentration) were measured was determined by randomization, with the results evaluated by an analysis of variance program. The second set deals with the effect of relative enhancement to salinity on selected ion and atom emission line pairs for various elements at 100 and 50% salinity relative to fresh water (0% salinity). These results are analyzed by a stepwise linear multiple regression analysis program using selected parameters of theoretical interest. It was discovered that the differences in relative enhancement for ion—atom emission line pairs for 100% salinity could be predicted basically with two variables. A coefficient of determination of 95% was achieved by employing the energy of transition for the atomic line and the number of unpaired d-electrons in the lower atomic state.