Abstract: A cervical ripening system includes a balloon catheter and a fluid pump. The fluid catheter has a balloon portion configured to pass through a cervix when contracted and to engage and pressure a uterine side of the cervix when expanded by fluid. The fluid pump is in fluid flow communication with the balloon portion of the catheter and is configured to selectively expand and contract the balloon portion of the balloon catheter by alternately pumping fluid into and out of the balloon portion of the balloon catheter to repetitively increase and decrease pressure on the uterine side of the cervix to simulate natural uterine contractions.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminals are connectable to a single phase AC power source, and connect directly to two output terminals of the converter. The phase converter has a storage capacitor, three active half bridge modules connected to the storage capacitor and a controller. Two modules connect to the input terminals and charge the storage capacitor. The other module connects to a third output terminal. The controller switches the module connected to the third output terminal and one of the other modules to generate and shape a second phase and a resultant third phase.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminals are connectable to a single phase AC power source, and connect directly to two output terminals of the converter. The phase converter has a storage capacitor, three active half bridge modules connected to the storage capacitor and a controller. Two modules connect to the input terminals and charge the storage capacitor. The other module connects to a third output terminal. The controller switches the module connected to the third output terminal and one of the other modules to generate and shape a second phase and a resultant third phase.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminals are connectable to a single phase AC power source, and connect directly to two output terminals of the converter. The phase converter has a storage capacitor, three active half bridge modules connected to the storage capacitor and a controller. Two modules connect to the input terminals and charge the storage capacitor. The other module connects to a third output terminal. The controller switches the module connected to the third output terminal and one of the other modules to generate and shape a second phase and a resultant third phase.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminals are connectable to a single phase AC power source, and connect directly to two output terminals of the converter. The phase converter has a storage capacitor, three active half bridge modules connected to the storage capacitor and a controller. Two modules connect to the input terminals and charge the storage capacitor. The other module connects to a third output terminal. The controller switches the module connected to the third output terminal and one of the other modules to generate and shape a second phase and a resultant third phase.

Abstract: A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations.

Abstract: A regenerative variable frequency drive includes an active converter connected to a DC bus that is connected to a first inverter that converts DC power to variable frequency, three phase AC power, and variable frequency, three phase AC power to DC power, and to a second inverter that converts DC power to three phase AC sine wave power. The converter converts single phase AC power to DC power and DC power to single phase AC power, and maintains a selected voltage on the DC bus. The converter has an active rectifier and a controller that drives the rectifier with a pulse width modulation according to a hybrid voltage switching scheme that switches the rectifier according to a unipolar voltage switching scheme through most of each cycle and switches the rectifier according to a bipolar voltage switching scheme around each zero crossing.

Abstract: A regenerative variable frequency drive includes an active converter connected to a DC bus that is connected to a first inverter that converts DC power to variable frequency, three phase AC power, and variable frequency, three phase AC power to DC power, and to a second inverter that converts DC power to three phase AC sine wave power. The converter converts single phase AC power to DC power and DC power to single phase AC power, and maintains a selected voltage on the DC bus. The converter has an active rectifier and a controller that drives the rectifier with a pulse width modulation according to a hybrid voltage switching scheme that switches the rectifier according to a unipolar voltage switching scheme through most of each cycle and switches the rectifier according to a bipolar voltage switching scheme around each zero crossing.

Abstract: A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations.

Abstract: In electrical resistivity tomography and electrical impedance tomography, interference effects of the metal well casing can be reduced by disposing measurement electrodes in the form of conductive bands around a region of primary insulation on the well casing. Secondary insulation can be provided longitudinally adjacent the primary insulation to further reduce the interference effects. Parameters of the primary and secondary insulation may be determined using finite element methods. The conductive band electrode can connect to a wire of a multi-strand cable using a novel takeout arrangement. Novel measurement methods are also described.

Abstract: A regenerative variable frequency drive includes an active converter connected to an inverter. The converter has a filter capacitor, an inductor, two half bridges, bus bars that connect to the inverter and bus capacitors. The converter converts single phase AC power to DC power and DC power to single phase AC power, boosts the AC power, reduces input line harmonics, maintains input current in phase with utility voltage in order to achieve near unity power factor, and maintains constant DC voltage between the bus bars.

Abstract: Methods and systems for determining an LPG fuel output characteristic of an LPG injector. The output characteristic of the LPG can be determined by calculating a total mass of LPG injected into a canister of known volume by the injector during a plurality of open/closed cycles of the injector. The pressure differential and temperature in the canister can be used in the calculation of total LPG mass along with a gas constant of the LPG and the volume of the canister. The total LPG mass can then be used to determine the mass of LPG injected by the injector during each open/closed cycle.

Abstract: A fuel system for supplying LPG fuel, the system including a fuel storage tank and a fuel transfer tank. A first pump pushes fuel to a vehicle engine from the transfer tank and excess fuel from the engine is returned to the storage tank or the transfer tank. A second pump pulls fuel from the storage tank into the transfer tank when a fluid level within the transfer tank falls below a certain level. A method of providing LPG fuel to the engine of a vehicle.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminals are connectable to a single phase AC power source, and connect directly to two output terminals of the converter. The phase converter has a storage capacitor, a charging circuit for controlled charging the storage capacitor and an output circuit for controlled discharge of the storage capacitor to provide single phase AC power to a third output terminal. The charging circuit controls input to the storage capacitor to provide a sinusoidal input current and to step up the voltage to the storage capacitor. The output circuit provides output power to the third output terminal of a predetermined phase and amplitude, relative to the other two output terminals, to result in balanced three phase AC power at the three output terminals.

Abstract: A phase converter that converts single phase AC electric power to balanced three phase AC power. Two input terminal connected to the output of a single phase AC power source connect directly to two output terminals of the converter. The phase converter has two serially connected storage capacitors with a common connection, a charging circuit for controlled charging the storage capacitors and an output circuit for controlled discharge of the storage capacitors to provide single phase AC power to a third output terminal. The charging circuit controls input to the storage capacitor to provide a sinusoidal input current and to step up the voltage to the storage capacitors. The output circuit provides output power to the third output terminal of a predetermined phase and amplitude, relative to the other two output terminals, to result in balanced three phase AC power at the three output terminals.