Update on testing the isotropy of the properties of gamma-ray bursts

Previously, we proposed a novel method to inspect the isotropy of the properties of gamma-ray bursts (GRBs), such as their duration, fluences and peak fluxes at various energy bands and different time-scales, complementary to existing studies of the spatial distribution of GRBs by other authors. The method was then applied to the Fermi Gamma-ray Burst Monitor (GBM) Burst Catalog containing 1591 GRBs. Except for one particular direction where we noticed some hints of violation from statistical isotropy, the rest of the data showed consistency with isotropy. In this work, we apply our method, with some minor modifications, to the updated Fermi GBM data sample containing 2266 GRBs, which is thus ∼40 per cent larger. We also test two other major GRB catalogues: the Burst And Transient Source Experiment (BATSE) Current GRB Catalog of the Compton Gamma Ray Observatory (CGRO), containing ∼2000 bursts, and the Swift Burst Alert Telescope (BAT) GRB Catalog, containing ∼1200 bursts. The new results using the updated data are consistent with our previous findings and we find no statistically significant anisotropic feature in the observed properties of these samples of all GRBs.

Anisotropic Thermal Transport in Magnetic Fluids

The inhomogeneous morphology of magnetic fluid may appear in the presence of an external magnetic field, which shows the structure controllability of magnetic fluid and will lead to anisotropic thermal transport inside the magnetic fluid. Based on the microstructure of magnetic fluid and considering the effect of nanolayer, a model for the thermal conductivity of the magnetic fluid has been developed. The anisotropic thermal transport inside the magnetic fluid is investigated by the present method. The results show that in the presence of an external magnetic field the particles form chainlike clusters along the magnetic field direction, which leads to an increment in the thermal conductivity along the field direction and little change in the thermal conductivity perpendicular to the magnetic field direction. The thermal conductivity of magnetic fluid presents an anisotropic feature. With the increase of the magnetic field strength the chainlike clusters in the magnetic fluid becomes more obvious and the anisotropic feature of heat conduction in the fluids becomes more evident. Comparisons show that the results predicted by the present method are well coincident with the experimental data.

Effect of Plasma Spraying Parameters on Anisotropic Feature of the Mechanical Property of Plasma Sprayed Al2O3 Coating

The effects of the plasma spraying parameters on the strength of an Al2O3 coating were investigated by changing the input electrical power to the plasma torch, the spray distance and the Al2O3 powder size as the spraying parameters. The anisotropic feature of the coating strength is also discussed. The strength of the Al2O3 coating in a direction perpendicular to a substrate plane was dominated by the layered structure of Al2O3 splats, and was affected by all the parameters. The strength of the coating in a direction parallel to the substrate plane was not affected by the input electrical power. The strength of the former was lower than that of the latter, in the coating containing many cracks. The anisotropy of the coating strength would be caused by the cracks propagating along the lines of the laminated layer.