Abstract:
A method for moving seismic streamers or acoustic energy sources through water in marine geophysical operations. The equipment can be deployed or retrieved from one or more vessels, and two or more tow vehicles maneuver seismic streamers through the water independently of a seismic vessel. Manned or unmanned tow vehicles can tow the streamers ahead of, behind, or to the side of a seismic vessel, or can form an array independent of the seismic vessel. Tow vehicles can be located at both ends to change the tow direction. The invention is particularly useful in customizing an array configuration, in reorienting the array at the end of each survey line, and permits deployment of receivers and sources in different combinations. By decoupling the tow vehicles and streamers from the source vessel, turning time at the survey region borders and the possibility of streamer entanglement is significantly reduced.
Abstract:
A high frequency cathode heater supply for a microwave source includes a SMPS inverter and an isolation transformer having a primary winding arranged to be powered by the SMPS inverter, a monitor winding passing through primary core assemblies of the primary winding and a secondary winding arranged for connection to the cathode heater. A current monitor is arranged to monitor a current in the primary windings. Signal processing modules are arranged to receive a first input signal from the monitor winding indicative of a voltage across the cathode heater and a second input signal from the current monitor indicative of a current through the cathode heater. The signal processing modules are arranged to output a control signal to the SMPS inverter to control power supplied to the cathode heater dependent on a monitored resistance of, or monitored power supplied to, the cathode heater as determined from the first input signal and the second input signal.
Abstract:
A high frequency cathode heater supply for a microwave source includes a SMPS inverter and an isolation transformer having a primary winding arranged to be powered by the SMPS inverter, a monitor winding passing through primary core assemblies of the primary winding and a secondary winding arranged for connection to the cathode heater. A current monitor is arranged to monitor a current in the primary windings. Signal processing modules are arranged to receive a first input signal from the monitor winding indicative of a voltage across the cathode heater and a second input signal from the current monitor indicative of a current through the cathode heater. The signal processing modules are arranged to output a control signal to the SMPS inverter to control power supplied to the cathode heater dependent on a monitored resistance of, or monitored power supplied to, the cathode heater as determined from the first input signal and the second input signal.
Abstract:
A system and method of displaying presentation slides. In one aspect, the system and method provides presentation slides based on a user request for information. Both the request information and the slides are associated with identifiers. A set of slides is chosen by determining whether there are any corresponding identifiers between the request for information and the presentation slides. The slides are also chosen such that the set of slides does not include any slides associated with identifiers which are a proper subset of the identifiers of any other slide in the set.