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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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Ethylene oxide concentration, humidity, time, and temperature parameters for large decontamination chamber
Absorption of pyrimidines, purines, and nucleosides by copper, nickel, cobalt, and iron montmorillonite
Spectra study and line classification of ions in fluorine I isoelectronic sequence from Sc XIII to C XXI
Impurity profiles and energy band diagram for cuprous sulfide-CdS heterojunction based on capacitance, Hall and electron microprobe measurements
Red, blue and no bias light effects on spectral response of copper sulfide-cadmium sulfide cell, using model incorporating photoconductive layer
A method is proposed for overcoming current difficulties in measuring atomic order parameters of nonrefractory metals when using the field-ion microscope (FIM). Near stoichiometric CuAu and Cu3Au were tested by means of this method. Images of substantially fully ordered CuAu and Cu3Au thus obtained are presented and discussed.
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Normalized differential and integral electron-impact cross sections are presented for elastic scattering and for specified excitation levels of atomic copper at 20 and 60 eV. For some excitation levels, an unexpectedly large cross section was found, which at certain angular and energy ranges surpasses the cross section for elastic scattering.
Nickel foils of nominal thickness 0.1 and 1 micron have been resistively evaporated onto copper-foil substrates of thickness 25 and 2.5 microns. In depositions in which the pressure was as high as 0.00001 torr, the deposited nickel was not shiny and appeared granular in a 100x microscope. Foils evaporated in higher vacuums were shiny, but became granular if heated to 500 C in oxygen at pressures greater than 0.000005 torr, or in carbon dioxide at pressures greater than 0.0000005 torr. This phenomenon has been interpreted as recrystallization. Foils heated to 500 C at pressures of hydrogen above 0.0003 torr exhibit cracking characteristic of hydrogen embrittlement. The bimetallic foils curled concave toward the nickel during evaporation, consistent with a connected-island form of film growth.
Cortical-evoked potentials were recorded from human subjects performing an auditory detection task with confidence rating responses. Unlike earlier studies that used similar procedures, the observation interval during which the auditory signal could occur was clearly marked by a visual cue light. By precisely defining the observation interval and, hence, synchronizing all perceptual decisions to the evoked potential averaging epoch, it was possible to demonstrate that high-confidence false alarms are accompanied by late-positive P3 components equivalent to those for equally confident hits. Moreover the hit and false alarm evoked potentials were found to covary similarly with variations in confidence rating and to have similar amplitude distributions over the scalp. In a second experiment, it was demonstrated that correct rejections can be associated with a P3 component larger than that for hits. Thus it was possible to show, within the signal detection paradigm, how the two major factors of decision confidence and expectancy are reflected in the P3 component of the cortical-evoked potential.
Tests show that Gold-Copper-Nickel alloy is compatible with ammonia systems. Joining tubes by brazing has advantages such as reducing chances of excessive grain growth in base metal, saving weight, and cleanliness.
Several samples of iron, copper, and magnesium doped lithium niobate were tested to determine their storage properties which would be applicable to an optical data storage system and an integrated optics data preprocessor which makes use of holographic storage techniques. The parameters of interest were the diffraction efficiency, write power, write time, erase time, erase energy, and write sensitivity. Results of these parameters are presented. It was found that iron doped lithium niobate samples yielded the best results in all parameters except for a few percent higher diffraction efficiency in copper doped samples. The magnesium doped samples were extremely insensitive and are not recommended for use in holographic optical data storage and processing systems.
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In continuation of single-conductor studies, quench onset data of quasi-steady operation are reported for a Formvar-coated composite (Nb48Ti/Cu) in bundle geometry (conductor thickness about 0.2 cm, approximately square cross section). Overall thermal conductances of the heater simulation technique applied are of the order 0.1 W/(sq cm-K), comparable to single-specimen results, around 4 K and below the lambda transition in agreement with model predictions. Considerable deterioration, however, occurs below 3 K and down to the lambda temperature during operation in near-saturated He I. Consequences for magnets of intermediate energy density are discussed with emphasis on the modifications necessitated by coatings.
Molecular dynamics was used to study the structure, dispersion and short-time behavior of ten-atom clusters adsorbed onto amorphous and crystalline substrates, in which the cluster atoms differed from the substrate atoms. Two adatom-substrate model systems were chosen; one, in which the interaction energy between adatom pairs was greater than that between substrate pairs, and the other, in which the reverse was true. At relatively low temperature ranges, increased dispersion of cluster atoms occurred: (a) on the amorphous substrate as compared to the FCC(100) surface, (b) with increasing reduced temperature, and (c) with adatom-substrate interaction energy stronger than adatom-adatom interaction. Two-dimensional clusters (rafts) on the FCC(100) surface displayed migration of edge atoms only, indicating a mechanism for the cluster rotation and shape changes found in experimental studies.
The Electrodynamics of the Middle Atmosphere research project encompasses the design of a microprocessor-controlled payload and the launch of up to eight small superpressure balloons in the 1982-1984 period. The primary payload instrument will measure the vector electric field from dc to 10 kHz, and the payloads will include instruments measuring local ionization, electrical conductivity, magnetic field, and temperature and pressure fluctuations. In addition, optical lightning will be recorded. The simultaneous measurement of these stratospheric parameters by several balloons, for periods extending over several solar rotations, will allow the study of electrical coupling between atmosphere and magnetosphere, of global current systems, and of global response to solar flares and magnetospheric storms.