Abstract: A pulsed high voltage power supply for use in a radiography system includes a high voltage step up transformer having a primary winding with first and second ends and a secondary winding connected to a radiation source. The power supply further includes a low voltage power source coupled to the first end of the primary winding and a switching circuit coupled to the second end of the primary winding. The switching circuit generates a switching signal having a series of pulses such that each pulse from the series of pulses causes the high voltage step up transformer to generate a high voltage pulse across the first and second electrodes to form a series of substantially uniform high slew rate high voltage pulses across the first and second electrodes of the radiation source.

Abstract: A pulsed high voltage power supply for use in a radiography system includes a high voltage step up transformer having a primary winding with first and second ends and a secondary winding connected to a radiation source. The power supply further includes a low voltage power source coupled to the first end of the primary winding and a switching circuit coupled to the second end of the primary winding. The switching circuit generates a switching signal having a series of pulses such that each pulse from the series of pulses causes the high voltage step up transformer to generate a high voltage pulse across the first and second electrodes to form a series of substantially uniform high slew rate high voltage pulses across the first and second electrodes of the radiation source.

Abstract: A pulsed high voltage power supply for use in a radiography system includes a high voltage step up transformer having a primary winding with first and second ends and a secondary winding connected to a radiation source. The power supply further includes a low voltage power source coupled to the first end of the primary winding and a switching circuit coupled to the second end of the primary winding. The switching circuit generates a switching signal having a series of pulses such that each pulse from the series of pulses causes the high voltage step up transformer to generate a high voltage pulse across the first and second electrodes to form a series of substantially uniform high slew rate high voltage pulses across the first and second electrodes of the radiation source.

Abstract: A method of preventing or retarding a combustible object from burning includes the steps of mixing water with a superabsorbent polymer ("SAP") to form one at least partially hydrated SAP, and applying the at least partially hydrated SAP to the combustible object, before or after combustion. In another embodiment, an article of manufacture includes a SAP, that is prehydrated, or hydrated at a later time, is useful for preventing a combustible object from burning, or for providing a human fire shield or preventing penetration of extreme heat or fire to a firefighter or other animal.

Abstract: Improved thyristor voltage switching circuits for connecting an a.c. voltage across a load are characterized by means for protecting the thyristors when in the off state against line voltage transients of an amplitude in excess of breakdown voltages thereof.In one embodiment of the invention, the thyristors are triacs connected in series to increase their overall voltage withstand capability. In another embodiment, circuitry is connected to sense the voltage between anode and cathode terminals of triacs, and to apply a signal to gate terminals thereof to render the triacs conductive whenever the anode to cathode voltage is in excess of the breakdown voltage. In this manner, surge currents are conducted across the entire junction areas of the triacs as compared with point areas, and destruction of the triacs is prevented.

Abstract: A circuit for switching a voltage between a pair of terminals by means of a thyristor, preferably a silicon controlled rectifier (SCR), connected at its anode to one of the terminals and at its cathode to the other terminal, is characterized by a control switch connected with a normally open contact thereof between the gate and the anode of the SCR, and with a normally closed contact controlling the voltage at the gate of the SCR. With the control switch in its normal or "off" condition, the SCR is nonconductive and the voltage at the gate thereof is controlled independently to adjust the voltage at which the SCR would be turned on by a rapidly increasing voltage between the terminals, i.e., to adjust its dv/dt withstand capability. With the switch in its "on" condition, the gate is disconnected from control voltage and connected to the anode of the SCR, thereby to minimize the gate current required to render the SCR conductive.