Abstract: A method for automated diagnosis of faults in a system containing repairable parts is performed by selecting a set of faults representing all known failures which can occur among the parts of the system, characterized by symptom data representing the expected passing or failing results for tests applied at selected test locations in the system, generating a fault/symptom matrix of the set of faults mapped to the expected passing and failing results for the selected test locations, then performing actual tests one or more test locations and correlating the actual passing or failing test results to the fault/symptom matrix in order to identify a suspect list of faults. Additional tests may be performed until the suspect list cannot be reduced further. For efficiency, the tests are selected according to which have most diagnostic significance. The design data for the parts of the system are captured and the fault/symptom matrix is preprocessed for diagnostic efficiency and speed during run time.

Abstract: The integrated electrochemical/chemical oxygen generating system of the invention includes a water electrolyzer combined with a chemical oxygen generating subsystem which converts hydrogen from the electrolyzer to a decomposable oxygen source such as hydrogen peroxide. The total oxygen output of such a system is greater than that possible from the electrolyzer alone while safely disposing of the electrochemically generated hydrogen.

Abstract: A gas detecting and measuring device and method highly selective for the detection of certain gases is described. The gas detector is capable of detecting and measuring a gas which can be electrochemically oxidized or electrochemically reduced at a voltage of between about 0.6 and 1.5 volts relative to a standard hydrogen electrode. The gas detecting and measuring device and process are highly selective for the oxides of nitrogen (NO.sub.x) and chlorine. The gas detecting device utilizes a hydrated, solid polymer electrolyte ion transporting membrane in electrical contact with an improved catalytic graphite sensing electrode. For detecting an oxidizable gas such as nitric oxide (NO), an improved graphite anode in contact with the solid polymer electrolyte is used with a cathode and a reference electrode as an electrochemical cell, and for detecting a reducible gas such as chlorine (Cl.sub.2) or nitrogen dioxide (NO.sub.

Abstract: A compact electrochemical gas sensing cell is described for detecting gases such as carbon monoxide, NO.sub.2, alcohol vapors, etc. The cell is characterized by temperature stability during zero-air operation so that background current with no gas flow is eliminated or minimized. This cell utilizes a hydrated, solid polymer electrolyte having reference, sensing and counter electrodes mounted on the surface thereof with one side of the membrane being flooded with distilled water to provide self-humidification of the cell by water vapor transport across the membrane. A potentiostatic circuit is utilized to control the potential on the sensing circuit and also to maintain a fixed potential difference between the reference and the sensing electrodes. In addition, the chemical, electrochemical, and thermal characteristics of the sensing and reference electrodes are matched so that the sensor is highly temperature invariant during zero-air operation.

Abstract: A compact electrochemical gas sensing cell is described for detecting gases which are either immediately dangerous to health such as carbon monoxide, NO.sub.2, etc., or represent a social or public welfare risk. The latter area, for example, may require determining alcohol breath content of a driver of a motor vehicle. The cell uses a hydrated, solid polymer electrolyte which has sensing and reference electrodes positioned on one side of the solid polymer electrolyte membrane and a counter electrode positioned on the other side. One side of the hydrated SPE membrane is flooded with distilled water so that incoming gases are brought to essentially 100% relative humidity by rapid vapor phase water transport across the membrane, thereby eliminating the need for external humidification in the form of bubblers and the like. An ionically conductive hydrated SPE bridge is formed on one side of the membrane and is located spatially to provide a low resistance path between the reference and sensing electrodes.