Abstract: A method of shutting down operation of a fuel cell system comprising a fuel cell stack, the method comprising the sequential steps of: i) ceasing a supply of fuel to the fuel cell stack; ii) closing a shut-off valve on an exhaust line in fluid communication with a cathode system of the fuel cell system, the cathode system comprising a cathode fluid flow path passing through the fuel cell stack; iii) pressurising the cathode system with an air compressor in fluid communication with a cathode air inlet port in the fuel cell stack; and iv) ejecting water from the cathode flow path.

Abstract: A method of starting operation of a fuel cell system which includes at least a fuel cell stack. the method includes opening an anode inlet valve to allow fuel to enter an anode volume of the fuel cell stack; then operating an air compressor in fluid communication with a cathode air inlet of the fuel cell stack to allow air to enter a cathode volume of the fuel cell stack; monitoring the temperature of the cathode inlet and/or outlet and operating a water injection system to inject water into the cathode volume once the temperature of fluid passing through the cathode inlet and/or outlet exceeds a preset level, wherein a current drawn from the fuel cell stack is limited to prevent a voltage measured across one or more cells in the fuel cell stack from falling below a first voltage threshold.

Abstract: An electrochemical fuel cell having an anode, an ion transfer membrane and a cathode has liquid water delivered to the fluid flow channels within the cathode so as to maintain a relative humidity of 100% throughout the fluid flow channels. A calibration method and apparatus is described for determining an optimum quantity or range of quantities of liquid water to be delivered to the cathode fluid flow channels under varying operating conditions. An operating method and apparatus is described that ensures an optimum quantity of liquid water is delivered to the cathode fluid flow channels under varying operating conditions.

Abstract: A fuel cell assembly provides for the delivery of fluid into a channel of a fluid flow field plate in alternating flow directions through the channel for delivery of the fluid to a membrane-electrode assembly. The fuel cell includes a fluid flow field plate having a channel for delivery of fluid to a membrane-electrode assembly, the channel having a first inlet/outlet port communicating therewith and a second inlet/outlet port communicating therewith; and a fluid delivery system connected to the fluid flow field plate adapted for bi-directional delivery of fluid into the channel of the fluid flow field plate.

Abstract: This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest.

Abstract: A method of enabling functional blocks for a controller includes encrypting a purchase code for a functional block of the controller based upon a unique controller identification number and an identifier number of the functional block. The purchase code is decrypted to obtain a decrypted controller identification number and a decrypted functional block identifier number. The functional block of the controller is enabled when the decrypted controller identification number is equal to the unique controller identification number and the decrypted functional block identifier number is equal to the functional block identifier number.

Abstract: This invention provides a method of broadcasting including the steps of providing a broadcast signal in a central frequency band of an FM radio channel; providing a first plurality of sub-carriers in an upper sideband of the FM radio channel; providing a second plurality of sub-carriers in a lower sideband of the FM radio channel; modulating a first group of the first plurality of sub-carriers with a complementary punctured convolution coded encoded version of program material; modulating a first group of the second plurality of sub-carriers with the complementary punctured convolution coded version of the program material; and transmitting the broadcast signal, the first group of the first plurality of sub-carriers and the first group of the second plurality of sub-carriers. In an all-digital version of the invention, the central frequency band may include a plurality of sub-carriers transmitted at a lower power level than that of the sub-carriers in the upper and lower sidebands.

Abstract: This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest.

Abstract: This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest.

Abstract: An apparatus for obstructing a standardized test form from view of all but the test taker. The apparatus permits a test taker to see the necessary portions of the answer sheet but obstructs and obscures the view of answer marks from shallow angles or from a distance.