Abstract: A fuel cell system is operated with the fuel supply pressure greater than the oxidant supply pressure to the fuel cell. This gives improved performance particularly when the fuel cell system is closed on the fuel side. The magnitude of fuel overpressure may be varied in accordance with variations in the fuel cell operating parameters.

Abstract: A fuel cell system is operated with the fuel supply pressure greater than the oxidant supply pressure to the fuel cell. This gives improved performance particularly when the fuel cell system is closed on the fuel side. The magnitude of fuel overpressure may be varied in accordance with variations in the fuel cell operating parameters.

Abstract: A composite membrane for use in a fuel cell membrane electrode assembly comprises a porous polymeric substrate and an impregnant partially filling the substrate such that the substrate comprises a first region having pores substantially filled with the impregnant, and a second substantially porous region. The impregnant comprises a cation exchange material. The cation exchange material covers one surface of the substrate in a dense surface layer, contiguous with the first region of the substrate. The substrate has greater than 10% residual porosity, and the composite membrane is substantially gas impermeable and has at least one substantially porous major surface.

Abstract: A composite membrane for use in a fuel cell membrane electrode assembly comprises a porous polymeric substrate and an impregnant partially filling the substrate such that the substrate comprises a first region having pores substantially filled with the impregnant, and a second substantially porous region. The impregnant comprises a cation exchange material. The cation exchange material covers one surface of the substrate in a dense surface layer, contiguous with the first region of the substrate. The substrate has greater than 10% residual porosity, and the composite membrane is substantially gas impermeable and has at least one substantially porous major surface.

Abstract: A hand-held surgical apparatus with supporting equipment comprising a mechanism for producing a pressurized jet of fluid which is sufficiently energetic to fragment diseased human and animal tissue without damaging adjacent healthy tissue. Preferably the apparatus includes a jet of fluid which impinges obliquely onto the operative area such that diseased tissue underneath overlying healthy tissue may be fragmented, especially finger-like extensions from tumorous growths of the skin. The jet rotated about a generally vertical axis such that the points of impact of the water from the jet upon the operative area describes circular patterns, thereby effectively and quickly distributing fragmenting energy over a wide operative area. A supporting vacuuming apparatus for aspirating effluent or expended fluid and fragmented tissue from the operative site.

Abstract: This invention is directed to a method and apparatus for drilling horizontal holes in geological strata from a vertical position. The geological structures intended to be penetrated in this fashion are coal seams, as for in situ gasification or methane drainage, or in oil-bearing strata for increasing the flow rate from a pre-existing well. Other possible uses for this device might be for use in the leaching of uranium ore from underground deposits or for introducing horizontal channels for water and steam injections.

Abstract: Rock drilling method and apparatus utilizing high pressure water jets for drilling holes of relatively small diameter at speeds significantly greater than that attainable with existing drilling tools. Greatly increased drilling rates are attained due to jet nozzle geometry and speed of rotation. The jet nozzle design has two orifices, one pointing axially ahead in the direction of travel and the second inclined at an angle of approximately 30.degree. from the axis. The two orifices have diameters in the ratio of approximately 1:2. Liquid jet velocities in excess of 1,000 ft/sec are used, and the nozzle is rotated at speeds up to 1,000 rpm and higher.

Abstract: A hydromechanical drilling tool which combines a high pressure water jet drill with a conventional roller cone type of drilling bit. The high pressure jet serves as a tap drill for cutting a relatively small diameter hole in advance of the conventional bit. Auxiliary laterally projecting jets also serve to partially cut rock and to remove debris from in front of the bit teeth thereby reducing significantly the thrust loading for driving the bit.