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A NEW METHOD OF LASER BEAM STEERING USING OPTICALLY CONTROLLED VOLUME DIFFRACTION GRATINGS IS PRESENTED. THIS CONCEPT HAS THE POTENTIAL FOR STEERING A LASER BEAM OVER A WIDE FIELD-OF-VIEW IN A RANDOM ACCESS FASHION AT HIGH SPEED.A METHOD IS INVESTIGATED FOR AUTOMATICALLY CONTROLLING THE SPACING AND ORIENTATION OF THE DIFFRACTION GRATING TO MAINTAIN HIGH EFFICIENCY OVER A WIDE FIELD-OF-VIEW. THE DI ...

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USE OF A SENSOR TO MEASURE THE OCULAR PULSE OF AIRCRAFT PILOTS UNDER STRESSFUL CONDITIONS, CAN PROVIDE THE BASIS FOR A COMPUTER CONTROLLED SYSTEM TO AUTOMATICALLY OR OTHERWISE LOSING CONTROL. BASIC NON-INVASIVE TESTS NORMALLY USED TO ESTIMATE AN INDIVIDUAL'S CIRCULATORY SYSTEM DO NOT PROVIDE ADEQUATE INDICATION OF CRITICAL PHYSIOLOGICAL "BREAK" POINTS. THE PRIMARY TECHNICAL OBJECTIVES IN PHASE I I ...

UNDER STEDILY REPEATED CYCLIC LOADING IMPOSED BY LIVE LOADS, FATIGUE CRACKS IN BRIDGES CAN BE INITIATED AT SMALL DEFECTS. BECAUSE DEFECTS CAN ELIMINATE THE INITIAL STAGE OF CRACK GROWTH, THE FATIGUE LIFE IS GREATLY REDUCED, ESPECIALLY IF FRACTURE IS CONTROLLED BY CRACK INITIATION. THEREFORE, THE FATIGUE CRACK GROWTH PROCESS IS REDUCE TO CRACK PROPAGATION AND UNSTABLE CRACK GROWTH. FATIGUE STUDIES ...

THIS RESEARCH ADDRESSES TECHNIQUES AND MATERIALS FOR ON-ORBIT MAINTENANCE AND REFURBISHMENT OF THERMAL CONTROL SURFACE COATINGS USED ON LONG-LIFE SPACECRAFT. IN MANY CASES, CONSERVATIVE ASSUMPTIONS ON THE EFFECTS OF LONG-TERM DEGRADATION HAVE DRIVEN THE DESIGN OF SPACECRAFT THERMAL SYSTEMS TOWARD OVER CAPACITY WHICH RESULTS IN WEIGHT, SIZE, COMPLEXITY, AND COST PENALTIES. IF CRITICAL SURFACES COUL ...

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A SPARK DISCHARGE DEVICE IS CONSIDERED AS A SENSOR FOR WATERVAPOR CONTAMINATION OF HIGH PRESSURE HELIUM GAS COOLANT IN HTGR'S (HIGH TEMPERATUE GAS REACTORS). IT IS NECESSARY TO CAREFULLY MONITOR WATER VAPOR LEVELS SINCE MORE THAN A FEW PARTS PER MILLION ADVERSELY AFFECTS REACTOR GRAPHITE STRUCTURES AND FUEL ASSEMBLIES. THE TECHNIQUE WOULD EMPLOY OPTICAL DETECTION OF HYDROXYL (OH) OR ATOMIC OXYGEN ...

DURING THE PRELAUNCH CHECKOUT OF THE SPACE SHUTTLE, IT IS CONTINUALLY FLUSHED WITH DRY N(2) IN ORDER TO PREVENT THE BUILDUP OF AN EXPLOSIVE CONCENTRATION OF THE H(2) AND O(2) PROPELLANTS DUE TO LEAKAGE. IN ORDER TO DETECT ANY POSSIBLELEAKS, THE FLUSHING GAS IS CONTINUOUSLY SAMPLED TO MAKE SURETHAT THE H(2) AND O(2) CONCENTRATIONS ARE BELOW 500 PARTS PER MILLION. A MASS SPECTROMETER IS PRESENTLY US ...