The invention illustrates and describes a method and apparatus for eliminating the noise and debris of explosive welding techniques. This is accomplished by placing the explosive in a complete enclosure so that both the sound and debris of the explosion are contained in the enclosure. The welding is accomplished by the explosive pressure applied through the wall of the enclosure to the pieces to be joined. The novelty of the invention is in eliminating the safety hazards and detrimental psychological effects of the loud noises and scattering of debris which result from use of unconfined explosive welding while maintaining the inherent simplicity of the technique. BACTERIAL ADENOSINE TRIPHOSPHATE AS A NASA Case No. GSC-11092-2 Great Britain, France, Canada, Address inquiries to: Goddard Space Flight Center Attn: Patent Counsel Mail Code: 204 Greenbelt, MD 20771 [Corresponding U.S. Patent-Application Pending] A method is provided for determining bacterial levels in urine samples, which method depends on the quantitative determination of bacterial adenosine triphosphate (ATP) in the presence of non-bacterial adenosine triphosphate. After the removal of nonbacterial ATP, the bacterial ATP is released by cell rupture and is measured by an enzymatic bioluminescent assay using an enzyme obtained from the firefly. A method of coating pigment particles is described for preventing degradation and discoloration by ultraviolet light. The chemical species utilized serve as recombination sites for the electrons and holes produced by the radiation. The chemical species selected for a particular pigment should be one equivalent such that stable oxidation stages are formed differing by one electronic charge. Zinc oxide pigments coated with ferri- and ferrocyanide are discussed as an example. *Patent rights in the United States are held by Stanford Research Institute. Foreign patent rights are available for licensing from NASA. A stored charge device of the general type designated as an MNOS field-effect transistor, has its operation improved by embedding a thin metal layer between two insulating films used in the transistor. The embedded metal layer technique is also used to provide a two-terminal thin-film stored charge device, consisting of a "metalinsulator-embedded metal-insulator-metal", sandwich structure which can be used in high-density memory arrays. This invention describes an improved solar cell of increased efficiency. The invention comprises a p-type GaAs crystal adjoining an n-type Ga1-xAly As crystal to form a p-n junction. The value of x varies linearly in the n-type crystal from x-0 at the junction of the two crystals to x = .7 at the opposite surface of the n-type crystal. Hence, when the said opposite surface of the n-type crystal is exposed to solar radiation, energy is delivered by the p-n junction more efficiently than it is delivered by prior p-n junction type solar cells. |