Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “dioxide”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Cost analysis of carbon dioxide concentrators

Methodology and cost estimating relationships, for flight-type and prototype CO2 concentrators, have been developed and presented. A validity check was made by comparing the molecular sieves system considered here and that developed for Skylab. The system evaluated here is twice the size of the Skylab system and is also more complex as it desorbs CO2 thermally and stores it in an accumulator. The cost estimates developed were found to be approximately 50 to 70% higher than the actual cost of the Skylab unit.

Yakut, M. M.↗
NASA NTRS1973

Uranium dioxide fuel cladding strain investigation with the use of CYGRO-2 computer program

Previously irradiated UO2 thermionic fuel pins in which gross fuel-cladding strain occurred were modeled with the use of a computer program to define controlling parameters which may contribute to cladding strain. The computed strain was compared with measured strain, and the computer input data were studied in an attempt to get agreement with measured strain. Because of the limitations of the program and uncertainties in input data, good agreement with measured cladding strain was not attained. A discussion of these limitations is presented.

Smith, J. R.↗
NASA NTRS1973

Power supply for carbon dioxide lasers

An improved ac power supply for a CO2 laser which eliminates the need for ballast resistors to excite a stable discharge is disclosed. The method involves the connection of an inductance in front of the rectifier. This procedure provides a nondissapative positive resistance effect for cancelling the negative differential resistance exhibited by the tube at frequencies below 2 KHz. Such an inductance setup also increases the efficiency of the system.

Schiffner, G.↗
NASA NTRS1973

Liquid carbon dioxide and the Martian polar laminae

One of the most important findings of the Mariner 9 mission was the existence of a set of apparent stacked layers in both the north and south polar regions of Mars. The total thickness of the laminated terrain is approximately several kilometers. Because the Martian atmosphere is composed largely of CO2 and because the frost point of CO2 is known to be reached in both polar regions, it has been assumed that the volatiles in the bright laminae are in appreciable part condensed CO2, although condensed H2O, and a CO2-H2O clathrate are also possible. As long as the ratio of CO2 to H2O is large, the physical properties will be dominated by the CO2.

Sagan, C.↗
NASA NTRS1972

Production of O/1S/ from photodissociation of carbon dioxide.

The production efficiency was measured with the aid of a method based on the detection of the OI (5577 A) 'green' line. A sodium salicylate screen was used to monitor the intensity of the photons. Measurements at each of several individual wavelengths are conducted. The relative production efficiencies are shown in a graph. The absolute scale for the efficiency was determined in essentially the same way as in the Cameron band work reported by Lawrence (1972).

Lawrence, G. M.↗
NASA NTRS1973

Hydrogen depolarized carbon dioxide concentrator performance improvements and cell pair structural tests

The investigations and testing associated with the CO2 removal efficiency and voltage degradation of a hydrogen depolarized carbon oxide concentrator are reported. Also discussed is the vibration testing of a water vapor electrolysis cell pair. Performance testing of various HDC cell pairs with Cs2CO3 electrolyte provided sufficient parametric and endurance data to size a six man space station prototype CO2 removal system as having 36 HDC cell pairs, and to verify a life capability exceeding six moths. Testing also demonstrated that tetramethylammonium carbonate is an acceptable HDC electrolyte for operating over the relative humidity range of 30 to 90 percent and over a temperature range of 50 to 80 F.

Huddleston, J. D.↗
NASA NTRS1973

A listing of wavenumbers and intensities of carbon dioxide absorption lines between 12 and 20 micrometers

A listing is given of the wavenumber, intensities at 300, 275, 250, 225, 200 and 175 k and energy of the lower state of CO2 absorption lines between 12 and 20 microns. They are ordered by wave-number and include 19 bands of C-12(O-16)2, 4 bands of C-13(O-16)2, 2 bands of C-12-O-16-O-18 and 1 band of C-12-O-16-O-17. The vibrational and rotational constants and the band intensities used to calculate the line parameters are tabulated.

Drayson, S. R.↗
NASA NTRS1974

Electrical heating tests of uranium dioxide external fuel configuration at emitter temperature of 1900 K

Testing of two fuel clad specimens for thermionic reactor application is described. The annular UO2 fuel was clad on both sides with tungsten; heat rejection was radially inward. The tests were intended to study inner clad stability, fuel redistribution, and fuel melting problems. The specimens were tested in a vacuum chamber using electron bombardment heating. Fuel structural changes were studied using periodic gammagraphs and posttest metallography. The first specimen test was terminated at 50 hours because of a braze failure. The second specimen was tested for 240 hours when an outer clad leak developed due to a tungsten-water reaction. The fuel developed numerous cracks on cooldown but the inner clad remained dimensionally stable. The fuel cover gas did not impede the rate of fuel redistribution. Posttest examination showed the fuel had not melted during operation.

Diianni, D. C.↗
NASA NTRS1972

High resolution spectroscopic measurements of carbon dioxide and carbon monoxide

A modified 1.83 meter Jarrell-Ash spectrometer is reported. The instrument was double passed and achieved a resolution of 0.05 cm at 15 micrometers. An integrating voltmeter was used to optimize the available integration time. Data were obtained in the 15 micrometer and 4.3 micrometer band of CO2 and the 4.6 micrometer and 2.3 micrometer bands of CO. The data are summarized and examples of typical spectra are given. All the data are stored on IBM cards.

Chaney, L. W.↗
NASA NTRS1974

Evaluation of a Liquid Amine System for Spacecraft Carbon Dioxide Control

The analytical and experimental studies are described which were directed toward the acquisition of basic information on utilizing a liquid amine sorbent for in use in a CO2 removal system for manned spacecraft. Liquid amine systems are successfully used on submarines for control of CO2 generated by the crew, but liquid amines were not previously considered for spacecraft applications due to lack of development of satisfactory rotary phase separators. Developments in this area now make consideration of liquid amines practical for spacecraft system CO2 removal. The following major tasks were performed to evaluate liquid amine systems for spacecraft: (1) characterization, through testing, of the basic physical and thermodynamic properties of the amine solution; (2) determination of the dynamic characteristics of a cocurrent flow absorber; and (3) evaluation, synthesis, and selection of a liquid amine system concept oriented toward low power requirements. A low weight, low power system concept was developed. Numerical and graphical data are accompanied by pertinent observations.

Breaux, D. K.↗
NASA NTRS1973

Photoionization of carbon dioxide

Investigation of the mechanism for dissociative ionization of CO2 on the basis of measurements of the yields of photoions from CO2. It is found that at photon energies immediately above the molecular ionization limit of 13.773 plus or minus 0.002 eV the photoion yield curve exhibits a number of closely spaced peaks in a pattern not resembling Rydberg series. Two fragment ions, O(+) and CO(+), are observed as products of dissociative ionization. The yield of O(+) follows a weak, oscillatory curve from the thermochemical threshold at 19.07 eV to 19.39 eV, where a sudden increase in O(+) yield is observed exactly at the onset of the state CO2(+)/C 2 Sigma g (+)/, indicating predissociation of this state of the molecular ion. The magnitude of the jump in O(+) yield at 19.39 eV suggests that this predissociation is the principal mechanism for dissociative ionization.

Mcculloh, K. E.↗
NASA NTRS1974

Dual photon effects in nitrogen dioxide photolysis

A previous study demonstrated two-photon consecutive absorption as being the most probable mechanism for the photodissociation of NO2 using a pulsed ruby laser at 6943 A. Additional data discussed here confirmed this and also examined an associated phenomenon, that of multiphoton induced fluorescence. The dissociation of NO2 by ON-O bond cleavage requires 3.4 eV, while the laser energy corresponds to 1.785 eV. The pooling of the energy of two photons would give more than enough energy to dissociate the NO2 into NO + O. Several mechanisms including (1) simultaneous absorption of two photons; (2) reaction of two singly excited NO2; (3) reaction of a singly excited NO2 with a ground state NO2; and (4) consecutive absorption of two photons were examined.

Hakala, D.↗
NASA NTRS1974

Climatic variations on Mars. II - Evolution of carbon dioxide atmosphere and polar caps

The long-term variations in the atmospheric pressure and the polar cap temperature of Mars resulting from the obliquity oscillations are discussed. In performing these calculations, the assumption is made that the atmosphere is in equilibrium with perennial CO2 ice deposits at the north pole, as is proposed by Leighton and Murray (1966). If heat transport by the atmosphere is neglected, the temperature of CO2 ice at the poles ranges from about 130 K to about 160 K, the corresponding atmospheric pressure rising from a few tenths of a millibar to about 30 mbar, respectively. The neglect of atmospheric heat transport probably underestimates the peak pressure. Because the altitude of the south cap is about 2 km higher than that of the north cap, CO2 ice is unstable there and will migrate to the north cap at a rate of about 10 g/sq cm yr, the implication being that the south residual cap is water ice. A simplified model of the annual polar caps and pressure fluctuations is also presented.

Ward, W. R.↗