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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

A Historical Review of Cermet Fuel Development and the Engine Performance Implications

This paper reviews test data for cermet fuel samples developed in the 1960's to better quantify Nuclear Thermal Propulsion (NTP) cermet engine performance, and to better understand contemporary fuel testing results. Over 200 cermet (W-UO2) samples were tested by thermally cycling to 2500 deg (2770 K) in hydrogen. The data indicates two issues at high temperatures: the vaporization rate of UO2 and the chemical stability of UO2. The data show that cladding and chemical stabilizers each result in large, order of magnitude improvements in high temperature performance, while other approaches yield smaller, incremental improvements. Data is very limited above 2770 K, and this complicates predictions of engine performance at high Isp. The paper considers how this material performance data translates into engine performance. In particular, the location of maximum temperature within the fuel element and the effect of heat deposition rate are examined.

Ceramic Nuclear Fuel↗
NASA NTRS1990

Ambient Pressure Test Rig Developed for Testing Oil-Free Bearings in Alternate Gases and Variable Pressures

The Oil-Free Turbomachinery research team at the NASA Glenn Research Center is conducting research to develop turbomachinery systems that utilize high-speed, high temperature foil (air) bearings that do not require an oil lubrication system. Such systems combine the most advanced foil bearings from industry with NASA-developed hightemperature solid-lubricant technology. New applications are being pursued, such as Oil- Free turbochargers, auxiliary power units, and turbine propulsion systems for aircraft. An Oil-Free business jet engine, for example, would be simpler, lighter, more reliable, and less costly to purchase and maintain than current engines. Another application is NASA's Prometheus mission, where gas bearings will be required for the closed-cycle turbine based power-conversion system of a nuclear power generator for deep space. To support these applications, Glenn's Oil-Free Turbomachinery research team developed the Ambient Pressure Test Rig. Using this facility, researchers can load and heat a bearing and evaluate its performance with reduced air pressure to simulate high altitude conditions. For the nuclear application, the test chamber can be purged with gases such as helium to study foil gas bearing operation in working fluids other than air.

Bauman, Steven W.↗
NASA NTRS1994

The strong Bell inequalities: A proposed experimental test

All previous experimental tests of Bell inequalities have required additional assumptions. The strong Bell inequalities (i.e. those requiring no additional assumptions) have never been tested. An experiment has been designed that can, for the first time, provide a definitive test of the strong Bell inequalities. Not only will the detector efficiency loophole be closed; but the locality condition will also be rigorously enforced. The experiment involves producing two Hg-199 atoms by a resonant Raman dissociation of a mercury dimer ((199)Hg2) that is in an electronic and nuclear spin singlet state. Bell inequalities can be tested by measuring angular momentum correlations between the spin one-half nuclei of the two Hg-199 atoms. The method used to make these latter measurements will be described.

Fry, Edward S.↗
NASA NTRS1971

Space shuttle: Static stability and control investigation of the NR-GD/C delta wing booster (B-15B-1) and a Reusable Nuclear Stage (RNS) M = 0.6 - 4.96

Experimental aerodynamic investigations were made in the NASA/MSFC 14 x 14 inch trisonic wind tunnel on a NR-GD/C 0.0031 scale model delta wing booster (B-15B-1) and reusable nuclear stage (RNS). Three basic configurations were tested: (1) the B-15B-1 booster alone, (2) the RNS alone, and (3) the booster with the RNS mounted piggyback. Six component force and moment data were recorded for each of these configurations over an angle of attack range from -16 deg to 4 deg at zero degrees sideslip, and over an angle of sideslip range from -10 deg to 10 deg at zero and -6 degrees angle of attack. The configurations were tested over a Mach number range of 0.6 to 5.0 with a nominal Reynolds number of 6.5 million per foot except for Mach 1.2 and 3.0 where the Reynolds number were 12.4 million and 4.4 million per foot respectively.

Allen, E. C.↗
NASA NTRS1972

The heavy particle hazard, what physical data are needed?

The physical data required to evaluate the radiation hazard from heavy galactic cosmic rays to astronauts on extended missions are discussed. The spectral characteristics, nuclear interaction parameters, and track structure of particles are emphasized. The data on the lower energy portion of the differential spectrum of the iron group and nuclear fragmentation in tissue and aluminum are tested, and results are shown.

Curtis, S. B.↗
NASA NTRS1973

Experimental and analytical study of one- and two-component flows in spherical chambers

A study was conducted to evaluate techniques for obtaining high inner-gas concentrations in a spherical cavity for application to the open-cycle gaseous-core nuclear rocket. The study included flow visualization tests with water and gases as the working fluids, calculations of the streamline distribution, and calculation and measurement of the inner-gas concentration with air and Freon-11 as the inner-stream gases. The cavity shape, the outer-stream injection conditions, the turbulent transport coefficients, and the buoyancy effects were found to affect the inner-stream flow patterns.

Johnson, B. V.↗
NASA NTRS1974

Performance of the electrical controls for the Mini-Brayton system

The design theory and performance of a breadboard of the proposed Mini-Brayton electrical control system is presented. The Mini-Brayton is a nuclear isotope powered dynamic power conversion system. Testing was performed with an electronic simulation of a turbine alternator. Data on the voltage regulation, speed control, power consumption, reliability and transient response are presented for the breadboard.

Birchenough, A. G.↗
NASA NTRS1982

Neutral hydrogen in elliptical galaxies with nuclear radio sources and optical emission lines

An H I detection survey of eleven elliptical galaxies with powerful nuclear radio sources was conducted, using the 305 m antenna of Arecibo Observatory, to test the hypothesis that large H I mass is conductive to the formation of nuclear radio sources in elliptical galaxies. The H I was detected in emission in UGC 09114 and was possibly detected in absorption in UGC 06671. Observations of the remaining galaxies were not sensitive enough to support or refute the hypothesis. Data was combined from other H I surveys and spectroscopic surveys to search for correlations of H I mass with other galactic properties and environmental conditions. Strong correlations of (O II) lambda 3727 emission with H I content and with nuclear radio power were found. The latter two properties may simply indicate, respectively, whether a significant amount of gas is available to be ionized and whether energy is provided by nuclear activity for ionization. No dependence of H I content on optical luminosity or on degree of isolation from other galaxies was found.

Dressel, L. L.↗
NASA NTRS1988

Safety research of insulating materials of cable for nuclear power generating station

The polymers PE, EPR, PVC, Neoprene, CSP, CLPE, EP and other similar substances are frequently used as insulation and protective covering for cables used in nuclear power generating stations. In order to test these materials for flame retardation, environmental resistance, and cable specifications, they were given the cable normal test, flame test, chemical tests, and subjected to design analysis and loss of coolant accident tests. Material was collected on spark tests and actual experience standards were established through these contributions and technology was accumulated.

Lee, C. K.↗
NASA NTRS1988

High power density electrodes for AMTEC

Trilayer tungsten/platinum electrodes have provided dramatic improvements in stable power densities in alkali metal thermoelectric converters (AMTEC) experimental cells. The specific power density required to achieve a system conversion efficiency of approximately 15 percent or more with temperatures appropriate to space nuclear power sources is examined. Thus, if the observed power densities are sustained for thousands of hours, prototype AMTEC space nuclear power systems can be designed and tested.

Bankston, C. Perry↗
NASA NTRS1989

Space radiation studies

Two Active Radiation Dosimeters (ARD's) flown on Spacelab 1, performed without fault and were returned to Space Science Laboratory, MSFC for recalibration. During the flight, performance was monitored at the Huntsville Operations Center (HOSC). Despite some problems with the Shuttle data system handling the verification flight instrumentation (VFI), it was established that the ARD's were operating normally. Postflight calibrations of both units determined that sensitivities were essentially unchanged from preflight values. Flight tapes were received for approx. 60 percent of the flight and it appears that this is the total available. The data was analyzed in collaboration with Space Science Laboratory, MSFC. Also, the Nuclear Radiation Monitor (NRM) was assembled and tested at MSFC. Support was rendered in the areas of materials control and parts were supplied for the supplementary heaters, dome gas-venting device and photomultiplier tube housing. Performance characteristics of some flight-space photomultipliers were measured. The NRM was flown on a balloon-borne test flight and subsequently performed without fault on Spacelab-2. This data was analyzed and published.

Source record↗
NASA NTRS2000

A Bridge Health Monitoring Method Using the Hilbert-Huang Transform: A Case Study

We have developed a new method for nondestructive instrument method to monitor the health of a bridge. This new method is based on a transient test load and simple data collection. The nuclear of the method is the new invented nonstationary and nonlinear time series analysis method, the Empirical Mode Decomposition and Hilbert Spectral Analysis. The final decision on the health of the bridge structure is based on the nonlinear characteristic of the data, and on the comparison between the free and the forced vibration frequencies. Thus this alternative method enjoys many advantages: (1) no a priori data required, (2) simple data collection, and (3) minimum traffic disruption. Results from a case study of the Shing-Nan Bridge in Hou-Wei will be reported.

Huang, Norden E.↗
NASA NTRS1998

Discovery of Associated Absorption Lines in an X-Ray Warm Absorber: Hubble Space Telescope Observations of PG 1114+445

The unified picture of X-ray/UV absorbers offers a unique opportunity to probe the nuclear environment of active galactic nuclei. To test the unified absorber scenario and to understand the physical properties of the absorber, we obtained the first UV spectrum of PG 1114+445 using the Hubble Space Telescope (HST) Faint Object Spectrograph. PG 1114+445 is known to have an X-ray ionized ('warm') absorber,so that UV absorption is predicted. The HST spectrum clearly shows strong UV absorption lines due to Lyalpha, C iv, and N v, blueshifted by approximately 530 km s(exp -1) with respect to the quasar redshift. Since both X-ray and UV absorbers are rare in radio-quiet quasars, these observations argue strongly that the X-ray and UV absorbers are closely physically related. perhaps identical. We place constraints on the parameters of the absorber and conclude that the mass outflow rate is comparable to the accretion rate in PG 1114+445.

Mathur, Smita↗
NASA NTRS2001

Discovery of Associated Absorption Lines in an X-Ray Warm Absorber: Hubble Space Telescope Faint Object Spectrograph Observations of MR 2251-178

The presence of a 'warm absorber' was first suggested to explain spectral variability in an X-ray spectrum of the radio-quiet quasi-stellar object (QSO) MR 2251-178. A unified picture, in which X-ray warm absorbers and 'intrinsic' UV absorbers are the same, offers the opportunity to probe the nuclear environment of active galactic nuclei. To test this scenario and understand the physical properties of the absorber, we obtained a UV spectrum of MR 2251-178 with the Faint Object Spectrograph on board the Hubble Space Telescope (HST). The HST spectrum clearly shows absorption due to Lyalpha, N v, and C IV, blueshifted by 300 km s(exp -1) from the emission redshift of the QSO. The rarity of both X-ray and UV absorbers in radio-quiet QSOs suggests these absorbers are physically related, if not identical. Assuming the unified scenario, we place constraints on the physical parameters of the absorber and conclude the mass outflow rate is essentially the same as the accretion rate in MR 2251-178.

Monier, Eric M.↗