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At least 973 records · Page 54

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NASA NTRS1979

Thick ceramic coating development for industrial gas turbines - A program plan

A program plan on a NASA-Lewis funded program is presented, in which effectiveness of thick ceramic coatings in preventing hot corrosion and in providing thermal insulation to gas turbine engine components are to be investigated. Preliminary analysis of the benefit of the thermal insulating effect of this coating on decreasing cooling air and simplifying component design appears very encouraging. The program is in the preliminary stages of obtaining starting materials and establishing procedures. Numerous graphs, tables and photographs are included.

Vogan, J. W.↗

NASA NTRS1979

Rates of the reactions of 1, 1, 1-trichloroethane /methyl chloroform/ and 1, 1, 2-trichloroethane with OH

Highly purified samples of the two chlorocarbons, trichloroethane and methyl chloroform, were reacted with OH over the temperature range of 278 to 460 K in a discharge-flow system with resonance flourescence detection of OH. Attention is given to the data obtained at various temperature levels and to the graph of Arrhenius' diagram. It is determined that the methyl chloroform reaction was slower and its temperature dependence somewhat steeper than the earlier measurements had indicated, probably due to the presence of faster reacting olefinic impurities in prior studies. Implications for stratospheric ozone reductions by C10-sub-x catalysis and for tropospheric OH-budget are briefly discussed.

Jeong, K.-M.↗

NASA NTRS1979

Convergent perturbation analysis of intense coherent multiphoton interactions

Use has been made of flow graphs to deduce Feenberg perturbation expansions for radiative interactions. It is demonstrated that these expansions can in certain cases be summed to provide closed form expressions for the molecular response. In particular, it is shown that the coherent state response can be obtained by the summation of a continued fraction perturbation expansion for the harmonic oscillator. Anharmonicity in the lower levels is treated and its shown to introduce Rabi flopping identifiable with multiphoton transitions among isolated tightly coupled subsystems of levels. Relevance to laser induced multiphoton excitation and energy level shift calculations in the presence of a strong field are also discussed.

Gower, M. C.↗

NASA NTRS1979

C IV resonance line profiles in O stars

Graphs of normalized fluxes derived from objective-prism spectra (from the S-019 experiment on Skylab), and C IV profiles are presented. The C IV resonance profile, when studied with respect to bolometric magnitude and effective temperature, reveals mass loss conditions without requiring precise mass loss rates. There is a clear trend in the C IV feature toward more fully developed P Cygni profiles at higher luminosities, and a significant velocity shift in the C IV absorption down to bolometric magnitude approximately equal to -7.7.

Parsons, S. B.↗

NASA NTRS1980

A microprocessor based high speed space-borne packet switch

The design and performance evaluation of a single microprocessor based packet switch for use on-board a satellite are presented. The primary design criterion is to maximize the system throughput. A number of protocols and their impact on the switch design are discussed. Stem and processor hardware architectures are described. The flow charts of the software required to accomplish the essential functions are presented and modification needed for use in a multisatellite network are also indicated. Maximum throughput attainable is calculated, desirable characteristics of microprocessors for this application are pointed out. A queue theoretic model of the packet switch has been developed. Analytical relationships of the average waiting times and the queue sizes at the queues and the overall average response time with the various design parameters of the switch have been obtained. A number of graphs showing the effect of variation in the number of input and output lines, data rates, destination functions, speed of output lines and some other design parameters on the performance of the switch are presented and discussed.

Arozullah, M.↗

NASA NTRS1980

Soft X-ray observations of the binary sigma Cr B with HEAO-1

The detection of X-ray emission in the 0.15-2 keV band from the vicinity of the radio-emitting binary star HD 146361 in the binary system sigma-Corona Borealis, with low-energy detectors of the HEAO A-2 experiment, is reported. Graphs are presented that show plots of count rate versus scan angle in half-degree bins, that are obtained from the superposition of the 13 source scans. Attention is given to source position and identification as well as to the energy spectrum of the source.

Agrawal, P. C.↗

NASA NTRS1980

The Copernicus ultraviolet spectral atlas of Iota Herculis

An ultraviolet spectral atlas is presented for the B3 IV star Iota Herculis, which has been scanned from 999 to 1467 A by the Princeton spectrometer aboard the Copernicus satellite. From 999 to 1422 A the observations have a nominal resolution of 0.05 A. At the longer wavelengths the resolution is 0.1 A. The atlas is presented in graphs. Lines identified in the spectrum are also listed.

Upson, W. L., II↗

NASA NTRS1980

New results from old data - Lunar photometric anomalies in Wildey and Pohn's 1962 observations

The anomalies in V magnitude in photometric data on lunar features obtained by Wildey and Pohn (1964) are analyzed in the three colors of their UBV observations. The data have been averaged with respect to phase and graphed, and deviations from the average have been tabulated for each color. Sigma equal to or exceeding 3 for V, B-V, and U-B measures are shown on table. These variations are found to be similar to the much larger body of observations of lunar transient phenomena (LTP). The data for 25 features with 25 observations each show that in terms of individual measures the frequency of anomalies is approximately 3%, similar to frequencies obtained in other analyses of LTP data.

Cameron, W. S.↗

NASA NTRS1980

Prediction of fiber composite mechanical behavior made simple

A convenient procedure is described for the determination of the mechanical behavior (elastic properties and failure stresses of angleplied fiber composite laminates using a pocket calculator. The procedure consists of simple equations and appropriate graphs of (plus or minus theta) ply combinations. The procedure can handle all types of fiber composites including hybrids. The versatility and generality of the procedure is illustrated using several step-by-step numerical examples.

Chamis, C. C.↗

NASA NTRS1980

Crater densities on the satellites of Mars

The density of craters larger than 1 km in diameter has been determined for the entire surface of Phobos, and half that of Deimos. Densities of craters as small as 10 m on Phobos and 5 m on Deimos have been measured for small areas of the satellites. On both objects, crater densities are similar and yield plots which have slopes close to -1.9 on both incremental and cumulative log-log graphs. These densities are close to those expected to obtain under equilibrium conditions. They are also near the maximum predicted, based on the fragmentation lifetimes of the two objects: that is, the densities are near to the maximum possible before such objects are likely to suffer an impact severe enough to disrupt them. While the observed crater densities cannot be converted to absolute ages in any rigorous fashion, they can be understood if the flux at Mars has been similar to that at the Moon and if the surfaces that we see today generally date back to the end of the period of heavy bombardment some 4 billion years ago. It is extremely unlikely that the surfaces are younger than 1 billion years. There are no large areas on Phobos for which crater densities differ by more than a factor of 3 from the average.

Thomas, P.↗

NASA NTRS1980

Forbidden lines of np/q/ ions. I - Detailed balance and line intensity ratios

The detailed balance equations are solved in the ground state terms of 37 ions of C, N, O, Ne, Mg, Si, S and Fe; atomic data for 235 transitions of these ions are tabulated, and 14 line ratios of q = 2,4 ions and eight line ratios of q = 3 ions are graphed. Forbidden emission lines of these ions are in the far and near UV, visible, and near and far IR regions of the spectrum. In addition, detailed calculations of the relative populations of the levels of the ground state are presented as a function of temperature and density.

Kafatos, M.↗

NASA NTRS1979

Temporal studies of compact galactic X-ray sources

Advances in X-ray astronomy due to temporal studies are discussed. Attention is given to X-ray temporal variability categorized into periodic, quasi-periodic, and chaotic. Approximately 95% of all known X-ray sources exhibit chaotic variability, in which there is no apparent pattern or periodicities. The orbits of seven binary X-ray sources are presented, along with empirical findings of neutron star masses. In addition, the interior structure of a supergiant star, HD 77581, is investigated by attempting to measure its apsidal motion. Graphs are provided for the power density spectrum of 4U 1626-67, GX301-2 Doppler delay data, and empirically determined error contours for the mass and radius of four companions stars in X-ray binary systems.

Rappaport, S.↗

NASA NTRS1979

Comments on TEC trends

The paper comments on published and projected thermionic-energy-conversion (TEC) performance trends. This commentary includes graphs and an appendix relating TEC performance parameters, plots of predicted and actual TEC trends, a figure relating projected cost of electricity to overall efficiency for TEC topping, and a discussion of the implications of these relationships.

Morris, J. F.↗

NASA NTRS1982

Economic Evaluation of Single-Family-Residence Solar-Energy Installation

Long-term economic performance of a commercial solar-energy system was analyzed and used to predict economic performance at four additional sites. Analysis described in report was done to demonstrate viability of design over a broad range of environmental/economic conditions. Report contains graphs and tables that present evaluation procedure and results. Also contains appendixes that aid in understanding methods used.

Source record↗

NASA NTRS1982

Manifold Insulation for Solar Collectors

Results of computer analysis of effects of various manifold insulation detailed in 23-page report show that if fluid is distributed to and gathered from array of solar collectors by external rather than internal manifold, effectiveness of manifold insulation has major influence on efficiency. Report describes required input data and presents equations that govern computer model. Provides graphs comparing collector efficiencies for representative manifold sizes and insulations.

Source record↗

NASA NTRS1982

Predicting the Strengths of Angle-Plied Laminates

Simplified convenient procedure has been developed that can be used to determine elastic and strength properties of angle-plied laminates. Method is suitable for use with pocket calculator. Consists of simple equations and graphs of ply combinations from most frequently used composites. Procedure makes use of well-known transformation equations, ply stress influence coefficients, and ply uniaxial composites including interply and intraply hybrids.

Chamis, C. C.↗

NASA NTRS1980

Illustration of year-to-year variation in wheat spectral profile crop growth curves

Data previously compiled on the year to year variability of spectral profile crop growth parameters for spring and winter wheat in Kansas, Oklahoma, and the Dakotas were used with a profile model to develop graphs illustrating spectral profile crop growth curves for a number of years and a number of spring and winter wheat segments. These curves show the apparent variability in spectral profiles for wheat from one year to another within the same segment and from one segment to another within the same year.

Gonzalez, P.↗

NASA NTRS1980

FBI fingerprint identification automation study. AIDS 3 evaluation report. Volume 2: Technical feasibility

The results of this effort are presented in a manner for use by both the AIDS 3 Operational and Economic Feasibility subtasks as well as the Development of Alternative subtask. The approach taken was to identify the major functions that appear in AIDS 3 and then to determine which technologies would be needed for support. The technologies were then examined from the point of view of reliability, throughput, security, availability, cost and possible future trends. Whenever possible graphs are given to indicate projected costs of rapidly changing technologies.

Mulhall, B. D. L.↗