Abstract: Apparatus and methods for regulating methanol concentration in a direct methanol fuel cell system without the need for a methanol concentration sensor. One or more operating characteristics of the fuel cell, such as the potential across the load, open circuit potential, potential at the anode proximate to the end of the fuel flow path or short circuit current of the fuel cell, are used to actively control the methanol concentration.

Abstract: A method and apparatus for water management in a direct oxidation fuel cell system includes a direct oxidation fuel cell, including: a housing surrounding an anode, a cathode, a protonically conductive electronically non-conductive membrane electrolyte disposed between the anode and the cathode, a current collector, and a gas-permeable liquid-impermeable membrane disposed on a side of the cathode opposite the electrolyte. Excess water accumulation is removed from an area between the membrane electrolyte and the gas-permeable liquid-impermeable membrane by a pressure differential generated, preferably by a pump. The pressure differential draws air to the surface of, into, or through the cathode diffusion layer. The pump can be driven by the electricity generated by the fuel cell.

Abstract: A fuel cell which provides improved performance during a cold start. Several embodiments are provided to enable the controlled introduction of fuel into the cathode of the fuel cell such that oxidation occurs, heat is released and the temperature of the fuel cell is raised. Such fuel may be introduced into the cathode directly or may be introduced into the anode and allowed to crossover an electrolytic membrane. Alternatively, the fuel may be directed through a special conduit which allows oxidation of some of the fuel as it flows through.

Abstract: Apparatus for non-contact determination of wafer resistance of a semiconductor wafer includes a first sensor element, separated from a surface of the wafer by a first air gap, for capacitively coupling an AC drive signal into a portion of the wafer. A second sensor element, separated from the surface of the wafer by a second air gap, capacitively couples an AC output signal out of the wafer portion. An inductor, in series connection with the sensor elements is included in the sensor/wafer circuit. A frequency of the AC drive signal is automatically tuned to a resonant frequency at which capacitance impedance of the first air gap and of the second air gap is canceled by inductive impedance of the inductor. A voltage value of the drive signal required to drive an AC current signal of fixed magnitude through the wafer portion is automatically determined. The voltage value provides a measure of wafer resistance.

Abstract: An enclosed direct oxidation fuel cell system is provided. The system is sealed with one or more layers of a plastic enclosure that conforms directly to the shape of the fuel cell system. The enclosure is substantially comprised of one or more layers of materials that are non-reactive with the fuel substance used in the fuel cell. In accordance with one aspect of the invention, one of the materials is a plastic film material that provides a good seal to substantially prevent liquids from escaping from the system. Yet, the enclosure is lightweight and conforms substantially to the exterior body of the fuel cell system so that it adds little or no bulk to the fuel cell system. The enclosure also prevents water from leaking out of the system. The enclosure materials may include color-changing properties so that in the event of a leak, it is visually apparent that liquid is in contact with the enclosure.

Abstract: For a direct oxidation fuel cell system in which the source fuel is diluted with a diluting fluid prior to entering the fuel cell generally, and for a Direct Methanol Fuel Cell System (DMFC) in which the methanol source fuel is diluted with water, the dielectric constant of the fuel mix comprising the source fuel and the diluting fluid is measured to determine the relative proportions of source fuel and diluting fluid within this fuel mix. This measurement may then be used in a feedback loop to control the subsequent mixing of the source fuel with the diluting fluid, and in particular, to adjust the mix in the event the fuel mix is too rich or too dilute as compared to a desired mixing proportion. Additionally, a second dielectric constant measurement is used to determine the source fuel level of a fuel tank providing source fuel to the fuel cell. Finally, an optional telecommunications link is used to automatically order a source fuel refill when the source fuel runs low.

Abstract: A direct oxidation fuel cell which rapidly increases output power in response to demand. A conduit and valve arrangement allows neat or concentrated fuel to be introduced directly into anode flow field plate effectively bypassing the normal, time-consuming fuel flow path and eliminating the accompanying delay. A controller senses the demand for power and opens or closes the valves as appropriate. In alternative embodiments, neat or concentrated fuel is supplied directly to the anode diffusion layer or a protonically conductive membrane.

Abstract: A direct methanol fuel cell (DMFC) system in which, in response to changes in the output power level of the cell, the concentration of methanol supplied to the anode is actively regulated. As a result, cross-over of methanol through the cell's membrane electrolyte is minimized, and operating efficiency is maintained over a wide dynamic range of output power levels.

Abstract: A fuel cell system including a housing defining an anode chamber and a cathode chamber and including a catalyst, a protonically conductive but electronically non-conductive membrane positioned between the anode chamber and the cathode chamber, a mixing chamber, a fuel chamber in fluid communication with the mixing chamber, and a first conduit having a first end connected to the anode chamber and a second end connected to the mixing chamber. The first conduit directs a fuel-water solution from the mixing chamber to the anode chamber. The system also includes a second conduit having a first end connected to the anode chamber and a second end connected to the mixing chamber, where the second conduit directs effluent from the anode chamber to the mixing chamber. A coalescing surface provided with at least one of said conduits collects effluent gas produced by said fuel cell.

Abstract: A Read-Modify-Write operation in a RAID system is done by separating the writing of new data and the writing of new parity, so that they are not done in parallel. This allows recovery to be performed at all stages, without requiring the excessive use of non-volatile cache, and minimizing the amount of time a span has to be locked. The invention accomplishes this by allowing one of the recoveries to be a recovery to the old data, before the write, with a signal to the host that the write operation failed in such a recovery situation, requiring the host to resend the data. This speeds up the entire operation while minimizing the use of resources while only requiring that in the rare instances of a failure during a particular part of the Read-Modify-Write, the host needs to resend the data.

Abstract: Apparatus for non-contact determination of wafer resistance of a semiconductor wafer includes a first sensor element, separated from a surface of the wafer by a first air gap, for capacitively coupling an AC drive signal into a portion of the wafer. A second sensor element, separated from the surface of the wafer by a second air gap, capacitively couples an AC output signal out of the wafer portion. An inductor, in series connection with the sensor elements is included in the sensor/wafer circuit. A frequency of the AC drive signal is automatically tuned to a resonant frequency at which capacitance impedance of the first air gap and of the second air gap is canceled by inductive impedance of the inductor. A voltage value of the drive signal required to drive an AC current signal of fixed magnitude through the wafer portion is automatically determined. The voltage value provides a measure of wafer resistance.

Abstract: A direct methanol fuel cell (DMFC) system is provided with a pump for pumping methanol into the cell. The pump is driven by carbon dioxide produced by the electro-chemical reaction at the anode of the fuel cell. Because the amount of CO2 generated is proportional to the power generated by the cell, and thus the amount of fuel demanded by the cell, the pump is self-regulating. The system may be integrated using microelectro-mechanical system fabrication techniques.

Abstract: A fuel cell system including a housing defining an anode chamber and a cathode chamber and including a catalyst, a protonically conductive, but electronically non-conductive membrane positioned between the anode chamber and the cathode chamber and a first vent, a fuel chamber in gaseous communication with the anode chamber via a first valve, a liquid chamber in gaseous communication with the anode chamber via a second valve, and a mixing chamber having a second vent. The mixing chamber is in gaseous communication with the anode chamber via a third valve and receives fuel from the fuel chamber through a fuel valve, liquid from the liquid chamber via a liquid valve, and liquid effluent from the anode chamber via a liquid effluent valve. The mixing chamber also provides a fuel mixture to the anode chamber via a fuel mixture valve. Using effluent gases, the present invention drives fluids between elements of the fuel cell system.

Abstract: A direct methanol fuel cell (DMFC) system is provided with a pump for pumping methanol into the cell. The pump is driven by carbon dioxide produced by the electrochemical reaction at the anode of the fuel cell. Because the amount of CO2 generated is proportional to the power generated by the cell, and thus the amount of fuel demanded by the cell, the pump is self-regulating. The system may be integrated using microelectromechanical system fabrication techniques.

Abstract: A water management system for a fuel cell having an anode chamber including a fuel, a cathode chamber in fluid communication with an oxidizing agent, and a proton conducting membrane electrolyte separating the chambers. The system includes a gas plenum, a first valve for controlling a first flow of a gas from the anode chamber into the gas plenum, and a second valve for controlling a second flow of the gas collected by the gas plenum into the cathode chamber. The first valve is opened allowing the first flow while the second valve is closed between the gas plenum and the cathode chamber so that effluent gas is collected in the gas plenum. When the amount of the effluent gas in the gas plenum reaches a predetermined value, the first valve is closed and the second valve is opened to allow the second flow.

Abstract: A method for determining labels for video fields by identifying the state of the field is disclosed. Some examples of a video field's state include the origin of the field as film or video, its relative location with respect to edit points, and in the case of film-originating material, the location within the standard sequential pattern which results from converting film to video. To determine the label of a video field, the conditional probability distribution for a particular sequence of states given the entire video sequence is calculated. This may be optimized by using dynamic programing to maximize the conditional probability function and thus the labels. To determine the conditional probability, first the joint probability distribution is determined for the observed video fields and the states. This joint probability is calculated by creating a data model and a structure model for the video sequence.

Abstract: A method and apparatus for water management in a direct oxidation fuel cell system includes a direct oxidation fuel cell, including: a housing surrounding an anode, a cathode, a protonically conductive electronically non-conductive membrane electrolyte disposed between the anode and the cathode, a current collector, and a gas-permeable liquid-impermeable membrane disposed on a side of the cathode opposite the electrolyte. Excess water accumulation is removed from an area between the membrane electrolyte and the gas-permeable liquid-impermeable membrane by a pressure differential generated, preferably by a pump. The pressure differential draws air to the surface of, into, or through the cathode diffusion layer. The pump can be driven by the electricity generated by the fuel cell.

Abstract: Apparatus and methods for regulating methanol concentration in a direct methanol fuel cell system are provided. The apparatus and methods do not require a methanol concentration sensor. One or more operating characteristics of the fuel cell, such as the potential across the load, open circuit potential or potential at the anode proximate to the end of the fuel flow path, are used to actively control the methanol concentration.

Abstract: This invention presents a method and apparatus for controlling the operating point, i.e. the output voltage or current, of a fuel cell to a desired value, efficiently transferring the available fuel cell power to a rechargeable battery and load, and isolating the fuel cell from the battery and load. Active control of the operating point of the fuel cell allows for optimized power output and fuel cell efficiency. This invention uses feedback from the input to regulate the input voltage or current. The output of the DC-DC converter either charges the battery or helps the battery supply the load, and is maintained equal to the battery voltage as the output of the DC-DC converter is directly connected to the battery.

Abstract: A method and apparatus for oxygen management in a direct oxidation fuel cell system is provided. The oxygen management apparatus forces oxygen (typically from ambient air) into the cathode chamber of the fuel cell to facilitate the flow of oxygen across the cathode face of the fuel cell. It does so by utilizing the carbon dioxide already produced in the chemical reaction on the anode chamber of the cell. In a first embodiment of the invention, a turbine assembly is placed in fluid communication with the anode chamber of the fuel cell. The turbine assembly is driven when the carbon dioxide produced at the anode chamber flows over the blades of a first turbine (which is referred to herein as “the vent turbine”). The vent turbine is attached to a drive shaft that is used to cause a second turbine (or fan) to draw oxygen (generally from ambient air) into the cathode chamber of the fuel cell. This drawn-in air forces oxygen over the cathode of the fuel cell.