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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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NASA NTRS1989

Acoustic temperature profile measurement technique for large combustion chambers

Measurement of times of flight of sound waves can be used to determine temperatures in a gas. This paper describes a system, based on this principle, that is capable of giving the temperature profile in a nonisothermal gas volume, for example, prevalent in a large furnace. The apparatus is simple, rugged, accurate, and capable of being automated for process control applications. It is basically an acoustic waveguide where the outside temperature profile is transferred to a chosen gas contained inside the guide.

Venkateshan, S. P.↗
NASA NTRS1989

Nonequilibrium shock layer temperature profiles from arc jet radiation measurements

Shock layer temperature profiles are obtained through analysis of radiation from shock layers produced by a blunt body inserted in arc jet flow. Spectral measurements have been made in a nitrogen flow of 54.4 gm/s at an enthalpy of 8.72 MJ/kg. Vibrational temperatures for N2+ are obtained by matching spectral regions from arc jet spectra with spectra generated using the NEQAIR code. Temperature profiles obtained from the radiation layers show a vibrational temperature higher than the rotational temperature near the front of the shock and both temperatures decrease as the flow approaches the body. The spectral measurements are made and analysis completed for four distances, from the surface of the blunt body. The corresponding shock layer thickness is approximately 3.6 cm. Although the shock layer appears to be in thermal nonequilibrium, the measured rotational temperature approaches the single temperature results of viscous shock layer calculations at this test condition.

Blackwell, Harvel E.↗
NASA NTRS1989

Vertical aerosol structure of Neptune - Constraints from center-to-limb profiles

New center-to-limb (CTL) equatorial region profiles of Neptune have been extracted from spatially well-resolved images. The 8900-A CTL profile entails the presence of material above the 5-mbar level whose optical depth is less than 0.5. CH4-band data admit of thin scattering hazes in the 0.4-1.5 bar pressure level, although optical depths must be lower than 0.05; so thin a haze falls short of the reflected flux at 6340 A, thereby implying the presence of another scattering layer deeper than 1.5 bars. A good fit to the observed reflectivity is obtained by a bright cloud layer with an optical depth of 3.0.

Hammel, H. B.↗
NASA NTRS1989

Analysis of wind profile temporal variability

The modulus of the maximum wind change is used here to assess wind change at the Shuttle launch site at Kennedy Space Center. Empirical and theoretical distributions of the maximum wind change are presented, and the effect of wind profile smoothing on wind change distributions is analyzed. The capability of wind profile systems to measure extreme wind change is described.

Adelfang, Stanlay I.↗
NASA NTRS1989

Electron density profiles in the background of LF absorption during Forbush-decrease and PSE

Based on the simulation of different Forbush decrease and particle precipitation effects in the D region, electron density profiles in the mid-latitudes the ionospheric absorption of low frequency (LF) radio waves was determined. The absorption variations at different frequenceis are strongly affected by the shape of the electron density profile. A structure appears which sometimes resembles the letter S (in a sloping form). Both the height (around 70 to 72 km) and the depth of the local minimum in the electron density contribute to the computed absorption changes of various degree at different frequencies. In this way several observed special absorption events can be interpreted.

Satori, G.↗
NASA NTRS1989

Computed profiles of the solar C I multiplets at 1561 and 1657 A

A nine-level atomic model is presented for C I lines synthesis in the sun. All the atomic parameters are based on recent experimental and theoretical data. Profiles of the multiplets at 1561 and 1657 A are computed from a model of the solar chromosphere. The sensitivity of the results to changes in the atomic parameters is examined. Partial frequency redistribution must be included in these lines to obtain agreement between calculated and observed profiles.

Mauas, Pablo J.↗
NASA NTRS1989

Thematic Mapper laser profile resolution of Holocene Lake limit, Great Salt Lake Desert, Utah

The limit of Great Salt Lake's maximum expansion onto the floor of the Great Salt Lake Desert during Holocene time is marked by a break in slope which is clearly depicted in terrain models which merge Thematic Mapper (TM) multispectral scanner data and Aerial Profiling of Terrain System (APTS) laser profile data. Mean elevations of APTS-coincident TM pixels are strongly correlated with reflectance in TM Bands 5 and 7 when and where sufficient moisture contrasts among terrain components are high. TM-APTS models and field surveys place the highest Holocene standing water at an elavation of 4221 ft (1286.7 m).

Merola, John A.↗
NASA NTRS1989

Mars Mission profile options and opportunities

Mars Mission profile options and mission requirements data are presented for earth-Mars opposition and conjuction class round-trip flyby and stopover mission opportunities. The opposition class flyby and sprint mission uses direct transfer trajectories to and on return from Mars. The opposition-class stopover mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg in order to reduce the propulsion requirement associated with the opposition-class mission. The conjuction-class mission minimizes propulsion requirements by optimizing the stopover time at Mars. Representative interplanetary space vehicle systems are sized to compare and show sensitivity of the initial mass required in low earth orbit to one mission profile option and mission opportunity to another.

Young, Archie C.↗
NASA NTRS1989

Instrument description of the airborne microwave temperature profiler

The microwave temperature profiler (MTP) is a passive microwave radiometer installed in the NASA ER-2 aircraft and used to measure profiles of air temperature versus altitude. It operates at 57.3 and 58.8 GHz, where oxygen molecules emit thermal radiation. Brightness temperature is measured at a selection of viewing elevation angles every 14 s. MTP was the only remote sensing experiment aboard the ER-2 during the Airborne Antarctic Ozone Experiment. This paper describes hardware, calibration, and performance aspects of the MTP.

Denning, Richard F.↗
NASA NTRS1989

Profiles of nitric oxide in the upper stratosphere

Results are presented from NO measurements obtained with a chemiluminescent NO detector and an in situ ozone instrument aboard high altitude balloons launched at Air sur L'Adour and Gap, France. NO profiles were obtained between 35 and 40 km in the late morning of September 17, 1987 and the early afternoon of June 18, 1988. The average NO concentration was 9 ppbv at 35 km, increasing with altitude to 11.5 ppbv at 40 km. The difference in the temperature profile significantly contributes to the observed change in the NO concentration.

Kondo, Y.↗
NASA NTRS1990

Velocity profiles of high-excitation molecular hydrogen lines

Profiles of three lines of molecular hydrogen near 2.2 microns, originating from widely spaced energy levels, have been measured at a resolution of 32 km/s at Peak 1 in the Orion molecular outflow. The three lines, 1 - 0 S(1), 2 - 1 S(1), and 3 - 2 S(3), are found to have identical profiles. This result rules out any significant contribution to the population of the higher energy levels of molecular hydrogen at Peak 1 by fluorescence, and is generally consistent with emission from multiple J-type shocks.

Moorhouse, A.↗
NASA NTRS1990

Line profiles and the kinematics of the narrow-line region in Seyfert galaxies

High signal-to-noise ratio and long-slit CCD spectra at about 100 km/sec resolution have been obtained for six high-ionization Seyfert galaxies. By subtracting the stellar absorption features with the aid of continuum templates, and using deblending techniques, the asymmetry indices of a number of optical emission-line profiles were measured, spanning a wide range in both ionization potential and critical density in each galaxy. The fundamental problem of the cloud-motion direction in the narrow-line region (NLR) has been studied, using these measurements and on the assumption that the preponderance of blueward profile asymmetries requires radial motion as well as a source of extinction. Simple and spherically symmetric NLR simulations are performed to demonstrate that infall and outflow models can be distinguished by comparing asymmetry indices as a function of ionization potential and critical density.

De Robertis, M. M.↗
NASA NTRS1990

Observations of gamma-ray line profiles from SN 1987A

Fully resolved gamma-ray line observations from the decay of Co-56 in SN 1987A are presented. Data are from the first two balloon flights of the Gamma-Ray Imaging Spectrometer. On day 433 (after the initial optical sighting) the 847 and 1238 keV lines from Co-56 were observed at 2.3 and 4.3 sigma significance. On day 613, the lines at 847, 1238, and 2599 keV were observed at 4.6, 3.4, and 1.9 sigma, respectively. The combined significance for the three-line complex in both flights is 7.8 sigma. Gaussian profiles yield acceptable least-squares fits to the lines. The line profiles are centered on the red side of the rest energy with typical velocity dispersions of about 3500 km/s FWHM, consistent with an optically thin source, but the line intensities are less than about 30 percent of those produced by the 0.075 solar mass of Co-56 determined from the bolometric light curve.

Tueller, J.↗
NASA NTRS1990

Global three-dimensional constituent fields derived from profile data

The success of three-dimensional simulations of stratospheric constituent variability depends critically on the initialization of the constituent fields within the global model. This paper describes a technique for generating global three-dimensional fields from vertical constituent proflies. The technique uses potential vorticity (q) and potential temperature (theta) to map the profiles onto the global domain. The profiles used here are obtained from a two-dimensional model calculation that reproduces the relationship between theta, q, N2O and O3 observed during the Airborne Arctic Stratospheric Expedition. The method is verified by comparison with satellite data, aircraft data, and model simulations.

Douglass, Anne R.↗
NASA NTRS1990

Determination of optimum fin profile for a zero-G capillary drained condenser

This paper presents the analytical formulation and numerical results for heat transfer in a high heat flux condenser that relies on capillary flow along shaped fins (Gregorig surfaces) and a drainage network embedded in the condenser walls. Results are shown for a variety of fin profile shapes in order to show the geometric trade-offs involved in seeking a maximum effective heat transfer coefficient for the fin. Predictions of the model show excellent agreement with previously reported measurements for steam. Based on this work, a profile has been selected for a 2 kW ammonia condenser currently under development for use in space. In that design the fin half width is 0.5 mm and the model predicts a heat transfer coefficient referred to the base of the fin of 9 W/sq cm deg C for a heat flux of 10/W sq cm at the base.

Mccormick, John A.↗
NASA NTRS1990

An algorithm for retrieving water vapor profiles in clear and cloudy atmospheres from 183 GHz radiometric measurements - Simulation studies

The latent heat represented by atmospheric water vapor is extremely important to the energetics of the earth system. Future satellites (NOAA and DMSP) will carry microwave radiometers designed to measure the profile of water vapor globally. The problem of retrieving water vapor from the measurements is highly nonlinear even in clear atmospheres and the addition of clouds only makes it more so. In this paper, an algorithm with several novel features, which will retrieve water vapor profiles from microwave radiometric measurements even in the presence of clouds, is developed. Simulations with this algorithm show a vertical resolution on the order of 3 km and that clouds are well handled in many, but not all, circumstances. The most surprising result is that clouds can actually improve the vertical resolution of the retrieval.

Wilheit, Thomas T.↗
NASA NTRS1990

Comparison of ozone profiles from ground-based lidar, electrochemical concentration cell balloon sonde, ROCOZ-A rocket ozonesonde, and Stratospheric Aerosol and Gas Experiment satellite measurements

A series of coordinated atmospheric ozone profile measurements was made during October and November 1988. Only SAGE II measurements made within 1000 km of both of the ground, sites were considered for this intercomparison study. It was found that, at least for the time of year of the study, SAGE II measurements agreed only when they were made much closer than 1000 km (less than 500 km) from the other sites, and this is explained in terms of the large latitudinal gradient observed in the ozone concentration profile. Agreement to 5 percent was seen between the instruments, over the altitude range from 20 to 50 km, when the measurements were made close together in both time and space.

Mcdermid, I. S.↗
NASA NTRS1990

Unusual infrared line profiles in the post-asymptotic giant branch star HD 56126

Brackett series lines with very broad inverted P Cygni and shell-like profiles have been detected toward the post-AGB star HD 56126. These profiles suggest that an active phase of mass loss has begun recently in this star. The star has had at least one previous episode of intense mass loss, attested to by its strong far-infrared emission. HD 56126 is also known for having a broad emission feature at 21 microns. The unidentified emission bands at 3.3 and 3.4 microns are also present in the spectrum of HD 56126, but the near-infrared spectrum provides little help in establishing the carrier of the 21 microns band.

Kwok, S.↗