To survey a subterranean structure, first measurement data according to a first electromagnetic survey technique and second measurement data according to a second, different electromagnetic survey technique are received. In particular embodiments, a composition including a carbon source, such as coal, is subjected to addition of energy, such as high energy reactive milling, producing a milling product enriched in hydrogenated tetrahedral amorphous diamond-like carbon compared to the coal. The first AC line is provided on the circuit board and connects the first terminal and the switching unit. The sensor data provides position and velocity data for objects proximate thereto. The sensing assembly also includes an extension member extending between the base and the sensor assembly. These check valves may employ a reed to control vapor flow or a spring and plate to control flow.