A high voltage is applied to an arc gap adjacent to a test specimen to develop a succession of high-frequency arc discharges. Those high frequency arc discharges generate pulses of ultrasonic energy within the test specimen without requiring the arc discharges to contact that test specimen and without requiring a coupling medium between those arc discharges and that test specimen. Those pulses can be used for detection of flaws, for measurement of certain properties of the test specimen, and for measurement of stresses within that test specimen. GRAPHITE-REINFORCED ALUMINUM COMPOSITE AND METHOD OF PREPARING THE SAME Graphite-reinforced aluminum composite material is prepared by coating high strength, high modulus, and low density graphite fiber with nickel, aligning the coated fibers between and in contact with aluminum sheets in a stacked array, and bonding the array into an integral body by application of heat and pressure. The resulting diffusion-bonded composite shows favorable mechanical properties, the graphite fibers remaining intact during the preparation process. Damaging reactions at the graphite surface are prevented by the protective nickel coating. The graphite-reinforced material prepared by the above method can be subjected to shaping or forming operations without breaking the fibers. MICROWAVE POWER TRANSMISSION SYSTEM WHEREIN LEVEL OF TRANSMITTED POWER IS NASA Case No. MFS-21470-1 Canada, France, Germany, Great Britain, Japan, Address inquiries to: Marshall Space Flight Cente [Corresponding to U.S. Patent No. 3,795,910] This invention is a microwave, wireless, power transmission syster in which the transmitted power level is adjusted to correspond wit power required at a remote receiving station in which deviations i power load produce an antenna impedance mismatch causin variations in energy reflected by the power receiving antenn employed by the receiving station. The variations in reflecte energy are sensed by a receiving antenna at the transmitting station and used to control the output power of a power transmitter. REFRACTORY PORCELAIN ENAMEL PASSIVE CONTROL COATING FOR HIGH TEMPERATURE ALLOYS NASA Case No. MFS-22324 Australia, Canada, France, Germany, Great Britain, Address inquiries to: Marshall Space Flight Center Attn: Patent Counsel Mail Code: A&PS-PAT [Corresponding U.S. Patent Application Pending] Many coating materials have been developed in the space program. This coating is an excellent thermal coating for exposed surfaces. These coatings have low solar absorptance and a high emittance to provide effective protection from solar radiation, reentry heating, dust, salt spray, etc. The coating of this invention meets these requirements and is easily cleanable and will maintain its physical integrity after severe thermal cycling. It is made up of a high-refractory-content boroaluminum silicate glass frit containing zirconium oxide, lithium fluoride, alkali metal and alkaline earth oxide-flux, zinc oxide and a submicron disperse phase of cubicstabilized zirconium oxide. GPO 879-257 |