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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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We describe a genome compiler which complies s-expressions to machine code, resulting in significant speedup of individual evaluations over standard GP systems.
The problem of tuning trajectory determination models for interplanetary navigation is a complex task requiring an intensive search of multiple dynamical and nondynamical models that yield trajectory solutions with minimal errors.
The Nanoelectronic Modeling Tool (NEMO) is a general-purpose quantum device design and analysis tool based on a fundamental non-equilibrium electron transport theory.
In recent years, pressure to reduce the costs of interplanetary missions has led to a heighted emphasis on designing missions with shorter flight times, smaller launch vehicles, and simpler flight systems.
Material variations on an atomic scale enable the quantum mechanical functionality of devices such as resonant tunneling diodes (RTDs), quantum well infrared photodetectors (QWIPs), quantum well lasers, and heterostructure field effect transistors (HFETs).
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Regolith thickness distribution at Lunar Orbiter sites, correlating thickness directly with cratering density
A simple model of interacting complex systems of species is tested to assess the binding behavior of monomeric nucleic acid and protein components during evolution. Nine representative amino acids are immobilized by the formation of an amide linkage on a prepared chromatographic support. Selective binding of ribonucleoside 5-phosphates in these amino acids is achieved under standardized conditions, and a site-binding model is derived to characterize the binding. It is shown that the binding behavior of the reactants during nucleic acid-protein interactions depends on the nature of the base and the amino acid. The results of the study are assessed as useful for the interpretation of more complex nucleic acid-protein systems and of their role in the evolution of the cell.
Experimental investigation of the key question of the origin of life concerning the chronological order in the primordial sequence of nucleic acid, protein, and cell. It is pointed out that, when viewed against the background of experiments on the selective reaction of basic homopolyamine acids with mononucleotides (Lacey and Pruitt, 1969; Woese, 1968), the experiments made help to establish a basis for understanding how information originally flowed from proteins to nucleic acids.
Discussion of the problem of lunar crater genesis in the light of some considerations prompted by lunar and Martian crater similarities. By analogy with the moon, Martian craters seem both to vary in initial shape according to the energy of the impact that formed them and to have been modified subsequently by endogenic and surface processes. A proposed model for the geologic development of large Martian and lunar craters outlines a time-dependent sequence of events. Craters which have undergone rapid isostatic adjustment on the moon have distinctive morphologies and occur preferentially along mare basin-upland margins.