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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Homogeneous semiinfinite dielectric substitution for finite plasma scab studied as means to simplify impedance analysis of aperture antenna radiating in inhomogeneous plasma medium
Coordination of substituted pyridine N-oxides with oxovanadium /IV/ cations, noting stoichiometric variations with changes
Synthesis of linear, double-chain, ladder polymers from substituted tetraphosphonitriles
Synthesis of linear, double-chain ladder polymers from substituted tetraphosphonitriles
Synthesis of linear, double chain ladder polymers from substituted tetraphosphonitriles
Synthesis of linear, double chain, ladder polymers from substituted tetraphosphonitriles
Preparation and dielectric properties of gadolinium substituted barium sodium niobate mixed crystals
Discussing REDUCE system and approach to substitution in design of symbolic mathematics system
Design and development of gravity substitute workbench using electrostatic and aerodynamic principles
Deleterious mutations and neutral substitutions, discussing molecular evolution model for DNA and proteins
Partial configurational thermodynamic functions of interstitial species in ternary solid solutions containing substitutional and interstitial solute atoms
Ternary solid solutions with substitutional and interstitial solute atoms, developing statistical mechanical interaction model
Modes alternative to general aviation and the substitutability of telecommunications technology in lieu of intercity travel are reviewed.
Absolute total electron-detachment cross sections and relative elastic-scattering cross sections are presented for collisions of H(-) or D(-) with He, Ne, Ar, and N2 for collision energies ranging from about 2 eV up to 100 eV. Special emphasis has been given to the effect of isotopic substitution. It was found that, with the exception of the helium target, the results cannot be in accord with a model using a localized complex potential. On the other hand, the results for H(-) or D(-) with He are in excellent agreement with predictions based on previous (local complex potential) analysis of differential elastic-scattering measurements.
Failure detection and substitution of a spare module is provided in a system having a plurality of phase staggered modules connected in parallel to deliver regulated voltage from an unregulated source. Phase control signals applied to the active converter modules are applied to the spare module through NOR gates associated with and disabled by the power output of respective modules such that failure of any one enables its phase control signal to be applied to the spare module, thus controlling the spare module to operate in the phase position of the failed module. A NAND gate detects when any one active module fails and enables a gate in the spare module, thus activating the spare module.
Ceramics such as silicon nitride and silicon carbide are currently receiving a great deal of attention as potential materials for advanced gas turbine engines. The primary advantage offered by ceramics is their high temperature capability which can result in turbine engines of improved efficiency. Other advantages when compared to the nickel and cobalt alloys in current use are raw material availability, lower weight, erosion/corrosion resistance, and potentially lower cost. The use of ceramics in three different sizes of gas turbine engines is considered; these are the large utility turbines, advanced aircraft turbines, and small automotive turbines. The effects of material substitutions are reviewed in terms of engine performance, operating economy, and secondary effects.
The synthesis of partially hydroxy-substituted phosphazene prepolymers amenable to processing into cellular, flexible polyurethane foams was investigated. Factors determined include (1) the environment of the hydroxyl group; (2) the ease of the hexachlorocyclotriphosphazene polymerization; (3) the nature of the nonreactive substituents; and (4) the mode of introduction of the hydroxyl entity. The specific approaches taken, the rationale of the selections made, and the results are discussed.
New proposal shows sprayed coal powder formed by extrusion of coal heated to plastic state may be inexpensive substitute for carbon black. Carbon black is used extensively in rubber industry as reinforcing agent in such articles as tires and hoses. It is made from natural gas and petroleum, both of which are in short supply.