These factors are the buried depth of the pipe, the detecting frequency of the GPR, the material of the pipe and the spacing of the measured points.
Michael McAlpine, a nanotechnology engineer at Princeton University, recently created a bionic ear by 3D-printing flexible electronics and cartilage; it can detect frequencies that no biological ear, human or other, can hear.
As mentioned before, the Gibbs artefact is created by restoring the amplitude of the detected frequencies, while setting the amplitudes of undetectable frequencies to zero.
Not required to have prior knowledge of existing harmonics, Prony analysis detects frequencies, magnitudes, phases, and especially damping factors of exponential decaying or growing transient harmonics.
The Rivet Joints, a derivative of the old Boeing 707 passenger plane, are SIGINT (Signals Intelligence) aircraft equipped with all sorts of antennae and sensors to eavesdrop on enemy transmissions and detect frequencies used by radio and radars, pinpointing where the emissions come from.
Johnston organs are precisely tuned to detect frequencies of 250 300 Hz, which includes the wing beat frequency.
The youngest zebrafish detected sounds up to 200 Hz (versus 2 kHz in our catfish), while older zebrafish detected frequencies up to 4 kHz.
The detected frequencies between M and S forms (0.6 3.9%) are similar to those (0.3 5.6%) estimated or found previously [17], [37], [38], [39].
Smallest juveniles revealed lowest auditory sensitivity and were unable to detect frequencies higher than 2 or 3 kHz; sensitivity increased in larger specimens by up to 40 dB, and frequency detection up to 6 kHz.
However, when cross-pollination was detected, frequencies varied considerably between individual hth mutant plants.
