Fluorescence decay of rare-earth ions in crystals.
Decay of fluorescent transitions excited by monochromatic radiations for most rare earths in hexagonal lanthanum chloride and other lattices
TRANSITION PROBABILITY↗
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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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Preparation and properties of positive temperature coefficient thin-film thermistors.
Sputtering, slurry and doctor-blade techniques for depositing thin thermistor films of lanthanum- doped barium-strontium-titanate for bolometer application
BARIUM TITANATE↗
New Satellite Structure of Nd (super 3 super plus) Ions in Rare-Earth Trichlorides
Nd ion satellite structure in neodymium and lanthanum trichlorides, noting dependence on host lattice and impurities
Cohen, E.↗
Decay of super 136 La and super 134 La.
Lanthanum isotopes beta decay, analyzing excitation of near spherical daughter nuclei of barium isotopes
Fessler, T. E.↗
A study of environmental effects upon particulate radiation-induced absorption bands in spacecraft thermal control coating pigments.
Simulated solar wind environment effects on zinc oxide/potassium silicate and lanthanum oxide/ potassium silicate spacecraft thermal control coating pigments
Douglas, N. J.↗
Averaging by relaxation and the dynamic Jahn-Teller effect
Strontium chloride lanthanum ion system with dynamic Jahn-Teller effect, indicating isotropic EPM spectrum resulting from averaging by relaxation
Boatner, L. A.↗
Promising catalyst for auto exhaust
Lanthanum cobalt oxide as potential auto exhaust catalyst from studies of activity in gas phase
Libby, W. F.↗
Measurements of the ionization probability of Cu and LaB6 simulated micrometeors
Micrometeor mass data from radiometer measurements, detailing Cu and lanthanum hexaboride ionization probability
Becker, D. G.↗
Study of impact cratering in lunar-like materials
Electrostatically accelerated microparticles are used to perform simulated micrometeoroid impact cratering experiments in oligoclase. Impact craters were obtained using iron, lanthanum hexaboride, and silicon as the projectile materials. Each particle material was impacted at normal incidence and at 30 and 60 deg oblique angles. Tabular data for all impacts are presented and central crater pit diameter normalized to particle diameter and the total spall diameter normalized to particle diameter are plotted vs impact velocity for nine particle/angle combinations and three crystal orientations. Impact crater characteristics are photodocumented as a function of impact velocity for the nine particle/angle combinations and three crystal orientations in oligoclase and at fixed impact velocity for six other minerals.
Roy, N. L.↗
Measurement of radiation exposure of astronauts by radiochemical techniques
A cosmic radiation dose to the Apollo 17 crew of 1.3 R was calculated from the specific activities of Na-24 in their postflight urine specimens. The specific activities of K-42, Cr-51, Co60, and Sb-124, introduced by injection into the astronauts, are extremely high in these specimens. The Fe-59 and Cs-137 levels are also reported and appear to be normal. The concentrations of Na, K, Rb, Cs, Ca, Sr, Ba, Cr, Fe, Co, Ag, Au, Zn, Cd, Hg, Sn, As, Sb, Se, Br, Sc, La, Sm, Eu, Tb, Hf, Ta, and Th were measured in urine specimens from the Apollo 17 astronauts by neutron activation analysis. Strontium, barium, gold, cadmium, lanthanum, samarium, europium, terbium, thorium, and tin are reported for the first time. The concentrations or excretion rates of bromine and the alkali metals exhibit singificantly reduced postflight levels and are generally lower than values observed for previous missions. Chromium concentrations reflect radiochromium injections.
Brodzinski, R. L.↗
Estimate of contribution of jet aircraft operations to trace element concentration at or near airports
Samples of ASTM type A jet fuel were analyzed for trace-element content by instrumental neutron activation techniques. Forty-nine elements were sought. Only ten, aluminum, gold, indium, lanthanum, titanium, vandium, barium, dysprosium, tellurium, and uranium, were observed at levels above the detection limits encountered; of these only aluminum, titanium, and barium were present at concentrations greater than 0.1 ppm. Estimates of exhaust gas concentrations are made, and the ambient contribution at or near airports is calculated by using the Los Angeles International Airport dispersion model. It is shown that the ambient contribution is about an order of magnitude below typical urban levels for virtually all elements sought.
Fordyce, J. S.↗
Physics of sub-micron cosmic dust particles
Laboratory tests with simulated micrometeoroids to measure the heat transfer coefficient are discussed. Equations for ablation path length for electrically accelerated micrometeoroids entering a gas target are developed which yield guidelines for the laboratory measurement of the heat transfer coefficient. Test results are presented for lanthanum hexaboride (LaB sub 6) microparticles in air, argon, and oxygen targets. The tests indicate the heat transfer coefficient has a value of approximately 0.9 at 30 km/sec, and that it increases to approximately unity at 50 km/sec and above. Test results extend to over 100 km/sec. Results are also given for two types of small particle detectors. A solid state capacitor type detector was tested from 0.61 km/sec to 50 km/sec. An impact ionization type detector was tested from 1.0 to 150 km/sec using LaB sub 6 microparticles.
Roy, N. L.↗
Estimate of contribution of jet aircraft operations to trace element concentration at or near airports
Samples of ASTM type A jet fuel were analyzed for trace element content by instrumental neutron activation techniques. Forty-nine elements were sought. Only ten, aluminum, gold, indium, lanthanum, titanium, vanadium, barium, dysprosium, tellurium, and uranium, were observed at levels above the detection limits encountered; of these only aluminum, titanium, and barium were present at concentrations greater than 0.1 ppm. Estimates of exhaust gas concentrations are made, and the ambient contribution at or near airports is calculated by using the Los Angeles International Airport dispersion model. It is shown that the ambient contribution is about an order of magnitude below typical urban levels for virtually all elements sought.
Fordyce, J. S.↗
Color to black-and-white converter
Lanthanum-modified lead zirconate titanate ceramic plate, when sandwiched between pair of conventional light polarizers, forms electrically controlled coverter for television camera. Assembly can be used with camera at remote site to enable camera to transmit color or black and white signal on command.
Perry, W. E.↗
Mossbauer effect in dilute iron alloys
The effects of variable concentration, x, of Aluminum, Germanium, and Lanthanum atoms in Iron lattice on various Mossbauer parameters was studied. Dilute binary alloys of (Fe-Al), (Fe-Ge), (Fe-Al) containing up to x = 2 a/o of the dilute constituent were prepared in the form of ingots and rolled to a thickness of 0.001 in. Mossbauer spectra of these targets were then studied in transmission geometry to measure changes in the hyperfine field, peak widths isomer shifts as well as the ratio of the intensities of peaks (1,6) to the intensities of peaks (2,5). It was shown that the concept of effective hyperfine structure field in very dilute alloys provides a useful means of studying the effects of progressively increasing the solute concentration on host lattice properties.
Singh, J. J.↗
Solid state electro-optic color filter and iris
The electro-optic properties of lanthanum-modified lead zirconate titanate (PLZT) ferroelectric ceramic material are evaluated when utilized as a variable density and/or spectral filter in conjunction with a television scanning system. Emphasis was placed on the development of techniques and procedures for processing the PLZT disks and for applying efficient electrode structures. A number of samples were processed using different combinations of cleaning, electrode material, and deposition process. Best overall performance resulted from the direct evaporation of gold over chrome electrodes. A ruggedized mounting holder assembly was designed, fabricated, and tested. The assembly provides electrical contacts, high voltage protection, and support for the fragile PLZT disk, and permits mounting and optical alignment of the associated polarizers. Operational measurements of a PLZT sample mounted in the holder assembly were performed in conjunction with a television camera and the associated drive circuits. The data verified achievement of the elimination of the observed white-line effect.
Source record↗
Research investigation of the physical interactions and phenomena associated with hypervelocity sub-micron particles
Signals from impact ionization plasmas were studied as a means of performing microparticle composition analysis. Impact ionization signal response was measured in a time-of-flight (TOF) system for lanthanum hexaboride, carbonyl iron, and aluminum microparticle impacts on a tantalum target, primarily in the 1 - 8 km/s velocity range. Oscilloscope photographs of representative ion TOF signal response are given for each material studied. Graphs and histograms are presented of the total charge collected as well as the charge collected in each observed ion mass group. Data show that ion signals consist primarily of the lower ionization potential elements over the 1 - 8 km/s range.
Roy, N. L.↗
Investigation of metal hydride materials as hydrogen reservoirs for metal-hydrogen batteries
The performance and suitability of various metal hydride materials were examined for use as possible hydrogen storage reservoirs for secondary metal-hydrogen batteries. Lanthanum pentanickel hydride appears as a probable candidate in terms of stable hydrogen supply under feasible thermal conditions. A kinetic model describing the decomposition rate data of the hydride has been developed.
ONISCHAK↗