Abstract: Low thermal expansion ceramics of essentially 100 percent cordierite solid solution are prepared by the devitrification of a glass frit compact having the nominal composition in weight percent 16 percent MgO, 30 percent Al.sub.2 O.sub.3, 54 percent SiO.sub.2. These ceramics exhibit adequate density and strength and are useful for example in the fabrication of gas turbine engine components such as rotor vanes and heat exchangers.

Abstract: In europium-activated alkaline earth mixed halide x-ray phosphor compositions the addition of minor amounts of yttrium significantly reduces afterglow or persistance. A syngeristic effect upon the reduction of afterglow is observed when both yttrium and lithium additives are both included. Additions of other rare earths and alkali metals are not effective to reduce afterglow. The effective amount of Y is from about 0.001 to about 0.1 moles of yttrium per mole of host. When lithium is used in conjunction with yttrium, about 0.001 to about 0.1 moles of lithium per mole of host is used.

Abstract: A mixture of from 5% to 95% by weight of calcium tungstate and from 5% to 95% of europium activated barium fluorochloride exhibits brightness and x-ray absorption characteristics superior to that which would be predicted from the foregoing properties of the individual phosphors. Intensifying screens employing the above mixtures have a speed in excess of the commercially available intensifying screens using the present calcium tungstate x-ray phosphors.