[1] We present a statistical analysis of the time evolution of ground magnetic fluctuations in three (12–48 s, 24–96 s and 48–192 s) period bands during nightside auroral activations. We use an independently derived auroral activation list composed of both substorms and pseudo‐breakups to provide an estimate of the activation times of nightside aurora during periods with comprehensive ground ma...

There has been increasing evidence that at least some GRBs are emission beamed. The beamed GRB afterglow evolution has been discussed by several authors in the ultra-relativistic case. It has been shown that the dynamics of the blast wave will be significantly modified by the sideways expansion, and there may be a sharp break in the afterglow light curves under certain circumstances. However, t...

[1] A new method has been developed that models the changes a wave-formed rippled sediment bed undergoes as it is actively evolving between two given equilibrium states due to a change in surface wave conditions. The transient analysis of rippled beds has received very little attention within the literature. Dynamic changes within ripple parameters have implications for the estimation of flow d...

In this paper, the correlation of reflection loss measured by an ultrasonic shear wave reflection method and the microstructure in cement-based material is investigated. Three cement pastes (Portland cement type I) with different water-cement ratios (0.35, 0.50 and 0.60) cured at 25 °C were examined. The ultrasonic shear wave reflection factor (WRF) was measured by the wave reflection technique...