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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 217 records · Page 12

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NASA NTRS1975

Pressure Contact Sounding Data for NASA's Atmospheric Variability Experiment (AVE 3)

The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 41 stations participating in the AVE III measurement program that began at 0000 GMT on February 6 and ended at 1200 GMT on February 7, 1975. Soundings were taken at 3-hour intervals during a large period of the experiment from most stations within the United States east of about 105 degrees west longitude. Methods of data processing, change in reduction scheme since the AVE II pilot experiment, and data accuracy are briefly discussed. An example of contact data is presented, and microfiche cards of all the contact data are included in the appendix. The AVE III project was conducted to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales of-motion interrelationships.

Fuelberg, H. E.↗

NASA NTRS1977

An improved lunar moment of inertia determination - A proposed strategy

A strategy for determining an improved lunar moment of inertia is proposed. An improved uncertainty in the lunar inhomogeneity parameter could reduce the core density error from 4.20 gr/cu cm to 0.1 gm/cu cm for the case of a lunar density model having a 300 km core radius. The current error of 0.0025 for the lunar inhomogeneity parameter is mostly due to the uncertainties in the C20 and C22 gravity harmonics. An optimum reduction strategy for obtaining an order of magnitude improvement in the gravity estimates is based on covariance analyses of Doppler data. The long-arc reduction method is shown to provide better results than the short-arc technique, and the use of an orbit with a 7000 km semimajor axis along with certain terms of up to degree and order eight is recommended.

Ananda, M. P.↗

NASA NTRS1978

Comparison of ozone concentrations obtained from Skylab eclipse and ozonesonde measurements

The satellite eclipse technique of ozone measurement is evaluated to determine its accuracy and resolution. The method of obtaining ozone concentrations from ground-based observations of eclipsing satellites is described, the theory of this method is outlined, and the data reduction procedure is summarized. It is shown that the satellite eclipse technique successfully measures the vertical distribution of ozone from 15 to 40 km with precisions ranging from + or - 12% between 20 and 35 km and + or - 25% at both 15 and 40 km. The ozone profile is found to be in good agreement with in situ measurements obtained from an ozonesonde launched near the eclipse tangent point at local sunset, the percent differences being less than 14% from 20 to 40 km.

Mcdougal, D. S.↗

NASA NTRS2014

Compositional Diversity of the Vestan Regolith Derived from Howardite Compositions and Dawn VIR Spectra

Howardite, eucrite and diogenite meteorites likely come from asteroid 4 Vesta [1]. Howardites - physical mixtures of eucrites and diogenites - are of two subtypes: regolithic howardites were gardened in the true regolith; fragmental howardites are simple polymict breccias [2]. The Dawn spacecraft imaged the howarditic surface of Vesta with the visible and infrared mapping spectrometer (VIR) resulting in qualitative maps of the distributions of distinct diogenite-rich and eucrite-rich terranes [3, 4]. We are developing a robust basis for quantitative mapping of the distribution of lithologic types using spectra acquired on splits of well-characterized howardites [5, 6]. Spectra were measured on sample powders sieved to <75 μm in the laboratories of the Istituto di Astrofisica e Planetologia Spaziali and Brown University. Data reduction was done using the methods developed to process Dawn VIR spectra [4]. The band parameters for the ~1 and ~2 μm pyroxene absorption features (hereafter BI and BII) can be directly compared to Dawn VIR results. Regolithic howardites have shallower BI and BII absorptions compared to fragmental howardites with similar compositions. However, there are statistically significant correlations between Al or Ca contents and BI or BII center wavelengths regardless of howardite subtype. Diogenites are poor in Al and Ca while eucrites are rich in these elements. The laboratory spectra can thus be directly correlated with the percentage of eucrite material contained in the howardites. We are using these correlations to quantitatively map Al and Ca distributions, and thus the percentage of eucritic material, in the current regolith of Vesta.

Mittlefehldt, D. W.↗

NASA NTRSDate not supplied

Microwave Interrogation of Woven Straps under Light Loading for Inflatable Applications

NASA uses woven straps for restraint layers in inflatable structures. This work investigates the use of microwaves to measure low level loading in the woven straps. More specifically, microwaves from a linearly polarized antenna are used to investigate four straps composed of Vectran and Kevlar with ratings of 6,000 lbs and 12,000 lbs of force. The straps are all lightly loaded from 2kg to 10kg in 2kg increments. The spectral centroid (SC) technique has been used for the dimensionality reduction method to evaluate the microwave data. The SC method was used to reduce the data from 10001 points to a single point that corresponds to the amount of load on the strap.

Microwave↗

NASA NTRS1982

Photogrammetric aspects of remapping procedures

Photogrammetric control generation is discussed. Techniques in remote sensing data reduction are described. Emphasis is placed on methods of rectification of aerial photography and frame photography. Examples of multispectral band scanner data that were processed are presented.

Mikhail, E. M.↗

DOE OSTI2024

Archetype-based Redshift Estimation for the Dark Energy Spectroscopic Instrument Survey

We present a computationally efficient galaxy archetype-based redshift estimation and spectral classification method for the Dark Energy Survey Instrument (DESI) survey. The DESI survey currently relies on a redshift fitter and spectral classifier using a linear combination of principal component analysis–derived templates, which is very efficient in processing large volumes of DESI spectra within a short time frame. However, this method occasionally yields unphysical model fits for galaxies and fails to adequately absorb calibration errors that may still be occasionally visible in the reduced spectra. Our proposed approach improves upon this existing method by refitting the spectra with carefully generated physical galaxy archetypes combined with additional terms designed to absorb data reduction defects and provide more physical models to the DESI spectra. We test our method on an extensive data set derived from the survey validation (SV) and Year 1 (Y1) data of DESI. Our findings indicate that the new method delivers marginally better redshift success for SV tiles while reducing catastrophic redshift failure by 10%–30%. At the same time, results from millions of targets from the main survey show that our model has relatively higher redshift success and purity rates (0.5%–0.8% higher) for galaxy targets while having similar success for QSOs. These improvements also demonstrate that the main DESI redshift pipeline is generally robust. Additionally, it reduces the false-positive redshift estimation by 5%–40% for sky fibers. We also discuss the generic nature of our method and how it can be extended to other large spectroscopic surveys, along with possible future improvements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS1974

A data reduction technique and associated computer program for obtaining vehicle attitudes with a single onboard camera

A detailed discussion of the application of a previously method to determine vehicle flight attitude using a single camera onboard the vehicle is presented with emphasis on the digital computer program format and data reduction techniques. Application requirements include film and earth-related coordinates of at least two landmarks (or features), location of the flight vehicle with respect to the earth, and camera characteristics. Included in this report are a detailed discussion of the program input and output format, a computer program listing, a discussion of modifications made to the initial method, a step-by-step basic data reduction procedure, and several example applications. The computer program is written in FORTRAN 4 language for the Control Data 6000 series digital computer.

Bendura, R. J.↗

NASA NTRS1978

Effect of sampling rate and record length on the determination of stability and control derivatives

Flight data from five aircraft were used to assess the effects of sampling rate and record length reductions on estimates of stability and control derivatives produced by a maximum likelihood estimation method. Derivatives could be extracted from flight data with the maximum likelihood estimation method even if there were considerable reductions in sampling rate and/or record length. Small amplitude pulse maneuvers showed greater degradation of the derivative maneuvers than large amplitude pulse maneuvers when these reductions were made. Reducing the sampling rate was found to be more desirable than reducing the record length as a method of lessening the total computation time required without greatly degrading the quantity of the estimates.

Brenner, M. J.↗

NASA NTRS2024

Development of a Data Fusion Methodology for Lineload Aerodynamic Databases for a Launch Vehicle during Liftoff and Transition

The need for databases for the distributed loading on launch vehicles during the early portion of flight necessitates the use of expensive computational flows in regimes where wake effects dominate. While also being expensive, this is a regime that computational tools tend to historically have problems simulating accurately. To help tackle this problem, a method of data fusion to combine computational results to wind tunnel derived force and moment data is developed. Using this method, significant reduction in computational costs and increases in confidence of the final product is possible and has been used to generate several databases for the Space Launch System (SLS) at NASA. While the full details of database generation are not part of this work, the crucial method at its core is developed here. Two SLS geometries are used throughout the work to demonstrate the techniques. These are two of the larger geometries and represent both planned crewed missions to the Moon as well as potential cargo missions to deep space. The method uses principal component analysis (PCA) to generate a reduced ordered model (ROM) to help fill in the full parameter space. Other similar techniques are explored, but were not found to have a significant result on the predictions of the ROM. Because the full number of components are kept to generate the model, this lack of difference is expected. This method is then extended to ensure that predicted surfaces match trusted force and moment data derived from wind tunnel testing. This extension is done by setting up a constrained optimization problem in order to minimize the deviation from the surface resolved computational data while still integrating to the desired values. When generating the constrained optimization problem, a weighting factor to balance these competing needs is introduced. The work compares previously introduced weighting terms from similar work to the proposed terms and shows that the previously used terms do not have as desirable behavior in this flow regime. This method is then expanded by developing a technique to incorporate uncertainty quantification into the developed data fusion methodology. This expansion takes a two pronged approach. One examines transferring the uncertainties in the force and moment database and characterizes how those adjustments change the predicted lineloads. The second looks at model form error and looks how rebuilding the model using slightly different data changes the predictions. These two terms are then combined in order to create an uncertainty model that takes both effects into account. The limitations of the proposed methods is then discussed as well as possible techniques to address these shortcomings.

Launch Vehicles↗

DOE OSTI2024

Data Analytics for Catalysis Predictions: Are We Ready Yet?

Catalysis informatics has received tremendous attention in recent years as a tool to design catalysts and discover unique descriptors that capture the relationships between chemical properties and catalytic performance. One of the stop-gaps in understanding catalytic effects, which is often ignored and limits the deployment of data science tools, relates to the lack of uniform data. The catalytic cleavage of C–X (X= H, C, N, and O) bonds is relevant to many fundamental catalytic processes. In this Perspective, we performed data analytics on four groups of C–X cleavage reactions that are common in production, upcycling, or reactive separation: the C–C cleavage in cyclopropyl alcohol, the C–H cleavage in hydroacylation reactions, the C–O cleavage in β-O-4 linkages, and the C–N cleavage in amides, using experimental data collected from the literature to understand their underlying correlations. Experimental variables of high impact are identified for each reaction by dimensionality reduction methods. We highlight the urgent need for experimental data sets that include full details on the reaction conditions, such as reagent concentration, reaction temperature, or time in machine-readable forms. We discuss the potential improvement of the data of these reactions and promising approaches such as autonomous experiments to fill the gaps in unbiased experimental data. Finally, we also address the early stage consideration of separation aspects in the experimental design of efficient catalytic systems for these fundamental examples of chemical reactivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1989

Laser holographic interferometric measurements of the flow in a scramjet inlet at Mach 4

The need for quantitative data is addressed by laser holographic interferometry (LHI) by efficiently recording and reducing high resolution density data. This paper investigates the potential to get quantitative data from an interferogram created from two separate holographic plates. THe LHI measurements were made on a scramjet inlet at Mach 4. LHI successfully generated results for both internal and external flows, and demonstrated its ability to map entire flow fields. Of the three data reduction techniques used, the four-bucket method gave better results than the three-bucket or three-by-three methods. This technique requires high quality holograms as well as a good resolution in the digital images to produce good data.

Mcarthur, J. Craig↗

NASA NTRS1970

Data user's notes of the radio astronomy experiment aboard the OGO-V spacecraft

General information concerning the low-frequency radiometer, instrument package launching and operation, and scientific objectives of the flight are provided. Calibration curves and correction factors, with general and detailed information on the preflight calibration procedure are included. The data acquisition methods and the format of the data reduction, both on 35 mm film and on incremental computer plots, are described.

Haddock, F. T.↗

NASA NTRS1975

Data for NASA's AVE 3 experiment: 25-mb sounding data and synoptic charts

The atmospheric variability experiment (AVE 3) is described and tabulated rawinsonde data at 25-mb intervals from the surface to 25 mb for the 41 stations is presented. The experiment was conducted between February 6 and February 7, 1975. Brief discussions are given on methods of data processing, changes in the reduction scheme since the AVE 2 pilot experiment, and data accuracy. An example of contact data is presented as well as synoptic charts prepared from the data.

Fuelberg, H. E.↗

NASA NTRS1977

The application of remote sensing to the development and formulation of hydrologic planning models: Executive summary

Methods for the reduction of remotely sensed data and its application in hydrologic land use assessment, surface water inventory, and soil property studies are presented. LANDSAT data is used to provide quantitative parameters and coefficients to construct watershed transfer functions for a hydrologic planning model aimed at estimating peak outflow from rainfall inputs.

Castruccio, P. A.↗

NASA NTRS1977

Wind tunnel test and calibration techniques for the measurement of damping and dynamic cross derivatives due to pitching and yawing

The paper shows how the oscillatory apparatus described previously by Orlik-Rueckemann et al. (1974) for determining cross and cross-coupling moment derivatives due to pitching and yawing oscillation is strengthened, extensively modified, and adapted to permit operation in a large continuous-flow wind tunnel. Particular attention is given to an electromagnetic three-degrees-of-freedom calibrating system developed to verify the validity of the experimental method and the various aspects of data reduction procedure. Typical results from calibration tests and from a series of wind tunnel experiments are presented. The only significant limitation is that the apparatus can only be used for models that are relatively small and have a conically-shaped longitudinal cavity.

Hanff, E. S.↗

NASA NTRS1989

Laser transit anemometer software development program

Algorithms were developed for the extraction of two components of mean velocity, standard deviation, and the associated correlation coefficient from laser transit anemometry (LTA) data ensembles. The solution method is based on an assumed two-dimensional Gaussian probability density function (PDF) model of the flow field under investigation. The procedure consists of transforming the data ensembles from the data acquisition domain (consisting of time and angle information) to the velocity space domain (consisting of velocity component information). The mean velocity results are obtained from the data ensemble centroid. Through a least squares fitting of the transformed data to an ellipse representing the intersection of a plane with the PDF, the standard deviations and correlation coefficient are obtained. A data set simulation method is presented to test the data reduction process. Results of using the simulation system with a limited test matrix of input values is also given.

Abbiss, John B.↗

NASA NTRS1991

Absolute extinction and the influence of environment - Dark cloud sight lines toward VCT 10, 30, and Walker 67

The range of validity of the average absolute extinction law (AAEL) proposed by Cardelli et al. (1988 and 1989) is investigated, combining published visible and NIR data with IUE UV observations for three lines of sight through dense dark cloud environments with high values of total-to-selective extinction. The characteristics of the data sets and the reduction and parameterization methods applied are described in detail, and the results are presented in extensive tables and graphs. Good agreement with the AAEL is demonstrated for wavelengths from 3.4 microns to 250 nm, but significant deviations are found at shorter wavelengths (where previous studies of lines of sight through bright nebulosity found good agreement with the AAEL). These differences are attributed to the effects of coatings on small-bump and FUV grains.

Cardelli, Jason A.↗