Abstract: A product and the process for preparing the same to improve the moisture resistance properties of epoxidized TGMDA and DGEBA resin systems by chemically incorporating chromium (III) ions therein without impairing the mechanical strength properties of the resins.

Abstract: An optical proximity sensor for optically detecting an object within a predetermined detection volume. More specifically, an optical proximity sensor is disclosed having an illuminator assembly including an illuminator lens (55) and a plurality of light-emitting diodes (53) located at first predetermined positions along the focal plane (54) of the illuminator lens (55). A detector assembly including a detector lens (65) and a plurality of photodiodes (60) located at second predetermined positions along the focal plane of the detector lens (65) is also provided. The two lenses are spaced apart a predetermined distance in accordance with the configuration of the light-emitting diodes (53) and the photodiodes (60) in order to define a predetermined detection volume. Each light-emitting diode has a corresponding photodiode, and their relative positions on their respective focal planes determine the detection volume defined by their overlapping fields of view.

Abstract: The object of the invention is to provide a low compression turbocharged diesel engine in which the turbocharger can be operated independently of the engine to power auxiliary equipment. As shown in FIG. 1, fuel and air are burned in a catalytic combustor 17 to drive the turbine wheel of turbine section 11a which is initially caused to rotate by starter motor 9. By opening flapper valve 26, compressed air from blower section 11b is directed to catalytic combustor 17 when it is heated and expanded, serving to drive the turbine wheel and also to heat the catalytic element 32 shown in FIG. 2. To start engine 10, valve 26 is closed, combustion is terminated in catalytic combustor 17, and valve 20 is then opened to utilize air from blower 11b for air driven motor 21. When engine 10 starts, the constituents in its exhaust gas react in the catalytic element 32 and the heat generated provides additional energy for the turbine section 11a.

Abstract: A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are processed so that the light output can be correlated to bacteria in the sample and system "noise" can be substracted from the readings.A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction. The light output is correlated with bacteria present. A standard and a blank are also processed so that the light output can be correlated to bacteria in the sample and system "noise" can be subtracted from the readings.

Abstract: A high voltage multijunction solar cell comprises a plurality of discrete voltage generating regions, or unit cells, which are formed in a single semiconductor wafer (10) and are connected together so that the voltages of the individual cells are additive. The unit cells comprise doped regions of opposite conductivity types (30, 32) separated by a gap. The method includes forming V-shaped grooves (16) in the wafer and thereafter orienting the wafer so that ions of one conductivity type can be implanted in one face (e.g., 16a) of the groove while the other face (e.g., 16b) is shielded. A metallization layer (22) is applied and selectively etched away to provide connections between the unit cells.

Abstract: An intrusion monitoring system includes an array of seismic sensors, such as geophones, arranged along a perimeter to be monitored for unauthorized intrusion as by surface movement or tunnelling. Two wires lead from each sensor to a central monitoring station. The central monitoring station has three modes of operation. In a first mode of operation, the output of all of the seismic sensors is summed into a receiver for amplification and detection. When the amplitude of the summed signals exceeds a certain predetermined threshold value an alarm is sounded. In a second mode of operation, the individual output signals from the sensors are multiplexed into the receiver for sequentially interrogating each of the sensors. Again, if the output from any one of the sensors exceeds a certain predetermined threshold value, a stop pulse is generated which stops the multiplexer at that sensor.

Abstract: A low cost coating protects metallic base system substrates from high temperatures, high gas velocity ovidation, thermal fatigue and hot corrosion. The coating is particularly useful for protecting vanes and blades in aircraft and land based gas turbine engines.A lacquer slurry comprising cellulose nitrate containing high purity silicon powder is sprayed onto the superalloy substrates. The silicon layer is then aluminized to complete the coating.The Si-Al coating is less costly to produce than advanced aluminides and protects the substrate from oxidation and thermal fatigue for a much longer period of time than the conventional aluminide coatings. While more expensive Pt-Al coatings and physical vapor desposited MCrAlY coatings may last longer or provide equal protection on certain substrates, the Si-Al coating exceeded the performance of both types of coatings on certain superalloys in high gas velocity oxidation and thermal fatigue.

Abstract: A controlled in situ etch-back technique is disclosed in which an etch melt 17 and a growth melt 18 are first saturated by a source-seed crystal 15 and thereafter etch-back of a substrate 14 takes place by the slightly undersaturated etch melt, followed by LPE growth of a layer by the growth melt, which is slightly supersaturated.

Abstract: The impact resistance of flame retardant composites, especially thermoplastic molding compounds containing over 60% hydrated mineral filler such as Al(OH).sub.3 or Mg(OH).sub.2 is improved by coating the filler with 1 to 20% of an elastomer. The composite will fail by crazing or shearing rather than by brittle fracture. A well bonded elastomeric interphase results by utilizing acidic substituted resins such as ethyl-hexyl acrylate-acrylic acid copolymers which bond to and are cross-linked by the basic filler particles. Further improvement in impact resistance is provided by incorporating 1 to 10% of a resin fiber reinforcement such as polyvinyl alcohol fibers that decompose to yield at least 30% water when heated to decomposition temperature.

Abstract: This invention is concerned with improving high temperature evaporation-condensation heat-transfer devices which have important and unique advantage in terrestrial and space energy 5 processing. The device is in the form of a heat pipe 10 comprising a sealed container or envelope 12 which contains a capillary wick 14.The temperature of one end of the heat pipe is raised by the input of heat from an external heat source 16 which is extremely hot and corrosive. A working fluid 18 of a corrosive alkali metal, such as lithium, sodium, or potassium transfers this heat to a heat receiver 20 remote from the heat source.In accordance with the invention the container 12 and wick 14 are fabricated from a superalloy containing a small percentage of a corrosion inhibiting or gettering element. Lanthanum, scandium, yttrium, thorium, and hafnium are utilized as the alloying metal.

Abstract: A mechanism 10 for diverting the flow in a wind tunnel from the wing 20 of a model being tested therein. The wing 20 is mounted on the wall 30 of a tunnel. A diverter plate 11 is pivotally mounted on the tunnel wall 30 ahead of the model. An actuator 18 fixed to the tunnel is pivotally connected to the diverter plate 11, by plunger 15. When the model is about to become unstable during the test the actuator 18 moves the diverter plate from the tunnel wall to divert flow about the wing and change the effective sweep angle thereof maintaining stable model conditions. The diverter plate is then retracted to enable normal flow.

Abstract: This invention is concerned with improving the efficiency of thermionic energy converters. The invention is particularly directed to the reduction of plasma losses in these converters.This beneficial technical effect is achieved by internal distribution of tiny shorted cesium diodes driven by the thermal gradient between the primary emitter (10) and the collector (12). Specifically, the tiny, shorted diode distribution (14) comprises protrusions of the emitter material (16) from the main emitter face (18) which contact the main collector face (22) thermally but not electrically. The main collector ends (20) of the protrusions are separated from the main collector by a thin layer of insulation (24), such as aluminum oxide.The diode effect will increase with the use of metals that adsorb cesium less readily for the main emitter ends of the tiny protrusions and metals that adsorb cesium more readily for the main collector ends of the protrusions.

Abstract: A mechanism 10 for constraining models 20 or sections thereof being wind tunnel tested which is deployed at the onset of aeroelastic instability, to forestall destructive vibrations in the model. The mechanism includes a pair of arms 11a and 11b pivoted to the tunnel wall 30 and straddling the model. Rollers 12a and 12b on the ends of the arms contact the model, and are pulled together against the model by a spring 17 stretched between the arms. An actuator mechanism 18 swings the arms into place and back as desired.

Abstract: A noise suppressor for installation on the discharge or aft end of a turbo fan engine. Within the suppressor are fixed annular airfoils which are positioned to reduce the relative velocity between the high temperature fast moving jet exhaust and the low temperature slow moving air surrounding the same. Within the suppressor nacelle is an exhaust jet nozzle which constrains the shape of the jet exhaust to a substantially uniform elongate shape irrespective of the power setting of the engine. Fixed ring airfoils within the suppressor nacelle therefore have the same salutary effects irrespective of the power setting at which the engine is operated.