While transmitted from down-hole to the surface, the combined signal is inevitably contaminated by various kinds of noise, which may have much bigger amplitudes or much higher frequencies than that of the encoded signal, so the received signal should be processed to pick out useful components.
Yesterday, a coalition of city, state and federal officials announced that money would now be spent to try to clean up a different type of transportation: privately owned harbor ferries, which are much bigger and are starting to appear with much more frequency around the city.
The intensity of occurrence may not be high enough to cause a serious hazard but the frequency of the events is in much bigger concern.
Because of the higher frequency of the 2D line, a much bigger shift between 10 and 40 cm–1 is observed.
"The results of the increased frequency and intensity of extreme weather-related events are having a much bigger impact in poor countries than in the US or Europe".
It was observed that there was a 25 53% drop in natural frequencies of the damaged slab compared to the undamaged slab, with a much bigger drop for the lower modes.
Comparing with the vibration of bottom, the frame shows the high frequency vibration (more than 50 Hz), which lead to the acceleration of frame's center is much bigger than the bottom's center in time history.
