SEARCH · Engineering Papers

Results for “co2”

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.

SourceResearch connectionFrom yearThrough year

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

At least 1,477 records · Page 82

All sources NASA NTRS DOE OSTI

NASA NTRS1981

Band parameters of N2O and CO2 determined by whole band analysis

Whole band analysis, a method of obtaining band parameters from spectra by nonlinear least squares fitting of calculated to observed spectra, has been applied to bands of N2O and CO2. The retrieved N2 broadened widths of the 02(0)00 - 00(0) and 12(0)0 - 00(0)0 bands of N2O suggest that the air broadened widths on the AFGL listing are about 10% high. The intensities and (C-12)(O-16)2 broadened widths of the 20002-00001 and 21102-01101 bands of (C-12)(O-16)(O-18) and the 20002-00001 band of (C-12)(O-16)(O-17) have also been determined.

Hawkins, R. L.↗

NASA NTRS1982

Analysis of CO2 bands near 2600 per cm

The parameters of three bands of CO2 near 2600 per cm have been determined by the nonlinear least squares method of whole-band analysis. Careful modeling of the effect of the Fourier transform spectrometer on the spectrum has made it possible to reduce the difference between the observed and calculated spectra to values close to the estimated noise in the experimental spectrum. In particular, it is found necessary to model the effects of phase error even though these are difficult to observe in the experimental spectra.

Hoke, M. L.↗

NASA NTRS1982

Rotational analysis of CO2 bands near 4 microns

The band constants of CO2 bands near 2600 per cm have been estimated by the nonlinear least squares method and spectral curve fitting. The synthetic spectra calculated from these constants predict experimental values accurately and give very similar values for the line positions (to within 0.003 per cm for all but the weakest lines).

Hoke, M. L.↗

NASA NTRS1982

A theoretical investigation of gaseous absorption by water droplets from SO2-HNO3-NH3-CO2-HCl mixtures

A physical-chemical model is developed and used to investigate gaseous absorption by water droplets from trace gas mixtures. The model is an extension of that of Carmichael and Peters (1979) and includes the simultaneous absorption of SO2, NH3, HNO3, CO2, and HCl. Gas phase depletion is also considered. Presented results demonstrate that the absorption behavior of raindrops is strongly dependent on drop size, fall distance, trace gas concentrations, and the chemical and physical properties of the constituents of the mixture. In addition, when gas phase depletion is considered, the absorption rates and equilibrium values are also dependent on the precipitation rate itself. Also, the trace constituents liquid phase concentrations may be a factor of six or more lower when gas depletion is considered then when the depletion is ignored. However, the hydrogen ion concentration may be insensitive to the gas phase depletion.

Adewuyi, Y. G.↗

NASA NTRS1982

The role of convective model choice in calculating the climate impact of doubling CO2

The role of the parameterization of vertical convection in calculating the climate impact of doubling CO2 is assessed using both one-dimensional radiative-convective vertical models and in the latitude-dependent Hadley-baroclinic model of Lindzen and Farrell (1980). Both the conventional 6.5 K/km and the moist-adiabat adjustments are compared with a physically-based, cumulus-type parameterization. The model with parameterized cumulus convection has much less sensitivity than the 6.5 K/km adjustment model at low latitudes, a result that can be to some extent imitiated by the moist-adiabat adjustment model. However, when averaged over the globe, the use of the cumulus-type parameterization in a climate model reduces sensitivity only approximately 34% relative to models using 6.5 K/km convective adjustment. Interestingly, the use of the cumulus-type parameterization appears to eliminate the possibility of a runaway greenhouse.

Lindzen, R. S.↗

NASA NTRS1984

Discharge Extracts Oxygen From CO2

Process under development supplies oxygen for life support in hazardous environments. Prototype CO2 reactor vessel produces oxygen from carbon dioxide at expense of about 100 watt-hours of electricity per liter of gas reduced. Design changes to improve efficiency include narrowing gap between walls to operate at lower voltages and increasing area of one electrode while decreasing area of other to reduce capacitance.

Luce, R. S.↗

NASA NTRS1982

A blackbody radiation-pumped CO2 laser experiment

Thermal radiation from a high temperature oven was used as an optical pump to achieve lasing from CO2 mixtures. Laser output as a function of blackbody temperature and gas conditions is described. This achievement represents the first blackbody cavity pumped laser and has potential for solar pumping.

Christiansen, W. H.↗

NASA NTRS1982

Transmission of CO2 in the atmosphere of Venus for the spectral region near 7 microns

The transmission in the 7-micron 'window' of Venus was calculated for a 7-layer model atmosphere. The synthetic spectra show that radiation from the layer 20-30 km above the surface would reach the top of the atmosphere between 6.2 and 7.0 microns if there were no absorption besides the isotopic CO2 bands; for the 7.0- to 8.2-micron region, the radiating level would be located 40-50 km above the surface of Venus. The brightness temperature for the entire region is 430 K; for the above two regions it is 494 and 341 K, respectively.

Young, L. G.↗

NASA NTRS1983

Experimental comparison of heterodyne and direct detection for pulsed differential absorption CO2 lidar

A pulsed dual-wavelength dual-CO2-laser differential-absorption lidar (DIAL) system has been developed which permits simultaneous heterodyne and direct detection of the same lidar returns. This system has been used to make an experimental comparison of the SNRs and statistical and temporal characteristics of the DIAL returns from several topographic targets. These results were found to be in general agreement with theory and were used to quantify the relative merits of the two detection techniques. The measured parameter values were applied to an analytical treatment to predict system trade-offs for the remote sensing of atmospheric species, with application to both path-averaged and range-resolved measurements.

Killinger, D. K.↗

NASA NTRS1983

Marine biological controls on atmospheric CO2 and climate

It is argued that the ocean is losing N gas faster than N is being returned to the ocean, and that replenishment of the N supply in the ocean usually occurs during ice ages. Available N from river and estruarine transport and from rainfall after formation by lightning are shown to be at a rate too low to compensate for the 10,000 yr oceanic lifetime of N. Ice sheets advance and transfer moraine N to the ocean, lower the sea levels, erode the ocean beds, promote greater biological productivity, and reduce CO2. Ice core samples have indicated a variability in the atmospheric N content that could be attributed to the ice age scenario.

Mcelroy, M. B.↗

NASA NTRS1983

Blackbody-pumped CO2 laser experiment

Christiansen, W. H.↗

NASA NTRS1983

Production of O(-) from CO2 by dissociative electron attachment

Dissociative electron attachment cross-section measurements for the production of O(-) from CO2 are performed using a crossed target-beam - electron-beam collision geometry and a quadrupole mass spectrometer. The relative flow technique is used in determining the absolute values of the cross sections. The attachment energies corresponding to the five cross-section maxima are given. They are 4.4 + or - 0.1, 8.2 + or - 0.1, 13.0 + or - 0.2, 16.9 + or - 0.2, and 19.4 + or 0.2 eV. Also given are the cross sections at these maxima: 1.43 x 10 to the -19th sq cm, 4.48 x 10 to the -19th sq cm, 8.1 x 10 to the -21st sq cm, 8.1 x 10 to the -21st sq cm, and 1.2 x 10 to the -20th sq cm, respectively.

Orient, O. J.↗

NASA NTRS1983

Diffusive separation of binary mixtures of CO2-H2 in a sonic-orifice expansion

The separation of binary gas mixtures of carbon dioxide and hydrogen in sonic-orifice-generated free jets is investigated over a source Reynolds number range of 100 to 3000 using the well-known electron beam fluorescence technique. The lighter species, hydrogen, is chosen as the minor species in order to examine the extent of the validity of Sherman's first-order diffusive separation theory for large separation. The diffusive separation of mixtures containing approximately 2, 5, and 20 percent hydrogen in carbon dioxide is investigated by experimentally determining the relative number densities of the two species as a function of centerline axial distance within the free jets. Sherman's diffusive separation theory is applied to the jets using axial Mach number profiles which were a combination of experimental and analytical results for gamma = 1.40 expansions. The gamma = 1.40 expansion is shown to approximate the CO2-H2 expansion quite well, and the calculated separation agrees remarkably well with the experimentally determined values.

Mccay, T. D.↗

NASA NTRS1983

Coherent CO2 lidar systems for remote atmospheric measurements

Several examples of applications of coherent CO2 Doppler lidar systems are summarized to illustrate the potential of these systems. The applications discussed include the use of continuous-wave systems for detecting and tracking aircraft wake vortices, transverse velocity measurements, and measurements of mass flow rates of high stack emissions. The use of pulsed coherent lidars is illustrated by applications involving the measurement of thunderstorm gust fronts, the measurement of wind profiles, and clear air turbulence detection. Following a summary of previous efforts, some current programs are reviewed. These include investigations into two-dimensional wind field measurements, atmospheric backscatter measurements, transverse velocity measurements, and the feasibility of space operations.

Bilbro, J. W.↗

NASA NTRS1984

Development of a global model for atmospheric backscatter at CO2 wavelengths

Several areas of research which contribute to the development of a global model for atmospheric backscatter at CO2 wavelengths are discussed briefly. A computer program was written which fits a bimodal log-normal model to an aerosol size distribution. A ten-layer atmospheric model used to study the effect of gravitational sedimentation on aerosol particle size distribution was expanded by incorporating the transport effect due to vertical diffusion. Future research directions are outlined.

Source record↗

NASA NTRS1984

Development of a global model for atmospheric backscatter at CO2 wavelengths

The effect of aerosol microphysical processes on the backscatter from an aerosol plume undergoing long-range atmospheric transport was studied. A numerical model which examines the effects of coagulation and sedimentation on an aerosol size distribution is under development and the initial results for a single homogeneous layer were obtained. Use was made of the SAGE/SAM II data set to study the global variation of aerosol concentration and, hence, to predict the variation of Beta sub CO2. Computer programs were written to determine the mean, median, and the probability distribution of the measured aerosol extinction as a function of altitude, latitude and geographical conditions. The first data sets analyzed in this way are under study. Data was used to study aerosol behavior over the U.S.A. and the Pacific Ocean.

Kent, G. S.↗

NASA NTRS1983

Stratospheric temperature profile from balloon-borne measurements of the 10.4-micron band of CO2

The technique of nonlinear least squares spectral curve fitting has been used to derive the stratospheric vertical temperature profile from balloon-borne measurements of the 10.4 micron band of CO2. The spectral data were obtained at sunset with the approximately 0.02 per cm resolution University of Denver interferometer system from a float altitude of 33.5 km near Alamogordo, New Mexico, on 23 March 1981. The r.m.s. deviation between the retrieved temperature profile and correlative radiosonde measurements is 2.2 K.

Rinsland, C. P.↗

NASA NTRS1984

Evidence for speckle effects on pulsed CO2 lidar signal returns from remote targets

A pulsed CO2 lidar was used to study statistical properties of signal returns from various rough surfaces at distances near 2 km. These included natural in situ topographic materials as well as man-made hard targets. Three lidar configurations were used: heterodyne detection with single temporal mode transmitter pulses, and direct detection with single and multiple temporal mode pulses. The significant differences in signal return statistics, due largely to speckle effects, are discussed.

Menzies, R. T.↗