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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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At least 199 records · Page 11

Protective coatings for chromium alloys.

Ductile metal clads and coatings of silicides, aluminides and noble metals to protect Cr alloys against nitrogen embrittlement and air oxidation

Grisaffe, S. J.↗

High-temperature nickel-brazing alloy

Gold-nickel brazing alloy, with 5 percent indium added to depress the melting point, is used for brazing of nickel-clad silver electrical conductors which operate at temperatures to 1200 deg F. Alloy has low resistivity, requires no flux, and is less corrosive than other gold-nickel, gold-copper alloys.

Powell, A. H.↗

Explosive cord

Device, jetcord, is metal-clad linear explosive of sufficient flexibility to allow forming into intricate shapes. Total effect is termed ''cutting'' with jetcord consistently ''cutting'' a target of greater thickness than can be penetrated. Applications include sheet metal working, pipe cutting and fire-fighting.

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CRT image recording evaluation

Performance capabilities and limitations of a fiber optic coupled line scan CRT image recording system were investigated. The test program evaluated the following components: (1). P31 phosphor CRT with EMA faceplate; (2). P31 phosphor CRT with clear clad faceplate; (3). Type 7743 semi-gloss dry process positive print paper; (4). Type 777 flat finish dry process positive print paper; (5). Type 7842 dry process positive film; and (6). Type 1971 semi-gloss wet process positive print paper. Detailed test procedures used in each test are provided along with a description of each test, the test data, and an analysis of the results.

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Evaluation of 2 possible further developments of the UK in-flight radiation warning meter for SSTS

A mass reduction of the moderator and the response to the nucleon flux, responsible for the tissue-star component of the total-dose equivalent rate using a high atomic number material, are discussed. Radiation situations at SST cruising altitudes (approximately 20 km) due to solar proton flares were simulated in the stratosphere and on the ground. Actual stratospheric situations due to galactic cosmic radiation with a limited range of quality factor values (2-4) were encountered during slow ascents by balloons to 36 km. Synthetic situations obtained from high and low energy acclerator radiations were used to obtain radiation distributions having a larger range of quality factor values (11/2-9) than experienced in the stratosphere. The measurements made in these simulations related to the directly ionizing, neutron and tissue-star components of dose-equivalent rate. Due to the restricted range of neutron spectra encountered in the stratosphere, a significant mass reduction of the moderator by 4 kg was made, with the moderator clad with cadmium or some other slow neutron absorber.

Wilson, I. J.↗

Evaluation, construction and endurance testing of compression sealed pyrolytic boron nitride slot insulation

A high-temperature statorette, consisting of an iron-27 percent cobalt magnetic lamination stack and nickel-clad silver conductors, was tested with pyrolytic boron nitride slot insulation. Temperatures were measured in each test to determine characteristics of slot linear heat conductance from statorette conductors. Testing was carried out to temperatures of approximately 1500 F in a vacuum environment of 10-8 torr. Three assemblies were built and tested, each having a different room temperature slot clearance. The final statorette assembly was subjected to a 100-hour vacuum aging test at 1400 F followed by 25 thermal cycles. Temperature data from the three assemblies showed that decreasing slot clearance and increasing compression loading did enhance heat transfer. The temperature difference between slot and lamination at 1400 F increased 4 F during the thermal aging and an additional 10 F during the 25 thermal cycles.

Grant, W. L.↗

Fabrication and test of a space power boiler feed electromagnetic pump. Part 1: Design and manufacture of pump

A three-phase helical induction electromagnetic (EM) pump has been designed and built. This pump was designed for use as the boiler-feed pump of a potassium Rankine-cycle space electric power system. The pump is constructed of high temperature materials including a T-111 duct, Hiperco 27 magnetic material, nickel clad silver conductor wire, and a completely inorganic insulation system. The pump is designed to deliver 3.25 lb/sec potassium at 1000 F with a developed head of 240 psi while being cooled by 800 F NaK. At these conditions, the overall pump efficiency is expected to be 18%.

Gahan, J. W.↗

Modification of codes NUALGAM and BREMRAD, Volume 1

The NUGAM2 code predicts forward and backward angular energy differential and integrated distributions for gamma photons and fluorescent radiation emerging from finite laminar transport media. It determines buildup and albedo data for scientific research and engineering purposes; it also predicts the emission characteristics of finite radioisotope sources. The results are shown to be in very good agreement with available published data. The code predicts data for many situations in which no published data is available in the energy range up to 5 MeV. The NUGAM3 code predicts the pulse height response of inorganic (NaI and CsI) scintillation detectors to gamma photons. Because it allows the scintillator to be clad and mounted on a photomultiplier as in the experimental or industrial application, it is a more practical and thus useful code than others previously reported. Results are in excellent agreement with published Monte Carlo and experimental data in the energy range up to 4.5 MeV.

Steyn, J. J.↗

Some observations on uranium carbide alloy/tungsten compatibility

Chemical compatibility between both pure and thoriated tungsten and uranium carbide alloys was studied at 1800 C for up to 3300 hours. Alloying with zirconium carbide appeared to widen the homogeneity range of uranium carbide, making additional carbon available for reaction with the tungsten. Reaction layers were formed both by vapor phase reaction and by physical contact, producing either or both UWC2 and W2C, dependent upon the phases present in the starting fuel alloy. Formation of UWC2 results in slow growth of the reaction layer with time, while W2C reaction layers grow rapidly, allowing equilibrium to be reached in less than 2500 hours at 1800 C. The presence of a thermal gradient had no effect on the reactions observed nor did the presence of thoria in the tungsten clad.

Phillips, W. M.↗

Out-of-core Evaluations of Uranium Nitride-fueled Converters

Two uranium nitride fueled converters were tested parametrically for their initial characterization and are currently being life-tested out of core. Test method being employed for the parametric and the diagnostic measurements during the life tests, and test results are presented. One converter with a rhenium emitter had an initial output power density of 6.9 W/ sq cm at the black body emitter temperature of 1900 K. The power density remained unchanged for the first 1000 hr of life test but degraded nearly 50% percent during the following 1000 hr. Electrode work function measurements indicated that the uranium fuel was diffusing out of the emitter clad of 0.635 mm. The other converter with a tungsten emitter had an initial output power density of 2.2 W/ sq cm at 1900 K with a power density of 3.9 W/sq cm at 4300 h. The power density suddenly degraded within 20 hr to practically zero output at 4735 hr.

Shimada, K.↗

Studies of thermionic materials for space power applications

Service life tests of LC-8 and LC-9 carbide-fueled thermionic converters are discussed. Post operational tests of the converters to show emitter diametric change, microstructures of cladding and fuel, and analysis of fuel composition are described. The fabrication and performance of high temperature thermocouples used in the test procedures are included.

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In-pile and out-of-pile testing of a molybdenum-uranium dioxide cermet fueled themionic diode

The behavior of Mo-UO2 cermet fuel in a diode for thermionic reactor application was studied. The diode had a Mo-0.5 Ti emitter and niobium collector. Output power ranged from 1.4 to 2.8 W/cm squared at emitter and collector temperatures of 1500 deg and 540 C. Thermionic performance was stable within the limits of the instrumentation sensitivity. Through 1000 hours of in-pile operation the emitter was dimensionally stable. However, some fission gases (15 percent) leaked through an inner clad imperfection that occurred during fuel fabrication.

Diianni, D. C.↗