Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “data processing methods”

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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

XANES spectroscopy of sulfides stable under reducing conditions

X-ray absorption near-edge structure (XANES) spectroscopy is a powerful technique to quantitatively investigate sulfur speciation in geologically complex materials such as minerals, glasses, soils, organic compounds, industrial slags, and extraterrestrial materials. This technique allows non-destructive investigation of the coordination chemistry and oxidation state of sulfur species ranging from sulfide (2–oxidation state) to sulfate (6+ oxidation state). Each sulfur species has a unique spectral shape with a characteristic K-edge representing the s → p and d hybridization photoelectron transitions. As such, sulfur speciation is used to measure the oxidation state of samples by comparing the overall XANES spectra to that of reference compounds. Although many S XANES spectral standards exist for terrestrial applications under oxidized conditions, new sulfide standards are needed to investigate reduced (oxygen fugacity, f O 2 , below IW) silicate systems relevant for studies of extraterrestrial materials and systems. Sulfides found in certain meteorites (e.g., enstatite chondrites and aubrites) and predicted to exist on Mercury, such as CaS (oldhamite), MgS (niningerite), and FeCr 2 S 4 (daubréelite), are stable at f O 2 below IW-3 but rapidly oxidize to sulfate and/or produce sulfurous gases under terrestrial surface conditions. XANES spectra of these compounds collected to date have been of variable quality, possibly due to the unstable nature of certain sulfides under typical (e.g., oxidizing) laboratory conditions. A new set of compounds was prepared for this study and their XANES spectra are analyzed for comparison with potential extraterrestrial analogs. S K -edge XANES spectra were collected at Argonne National Lab for FeS (troilite), MnS (alabandite), CaS (oldhamite), MgS (niningerite), Ni 1–x S, NiS 2 , CaSO 4 (anhydrite), MgSO 4 , FeSO 4 , Fe 2 (SO 4 ) 3 , FeCr 2 S 4 (daubréelite), Na 2 S, Al 2 S 3 , Ni 7 S 6 , and Ni 3 S 2 ; the latter five were analyzed for the first time using XANES. These standards expand upon the existing S XANES end-member libraries at a higher spectral resolution (0.25 eV steps) near the S K -edge. Processed spectra, those that have been normalized and “flattened,” are compared to quantify uncertainties due to data processing methods. Future investigations that require well-characterized sulfide standards, such as the ones presented here, may have important implications for understanding sulfur speciation in reduced silicate glasses and minerals with applications for the early Earth, Moon, Mercury, and enstatite chondrites.

Anzures, Brendan A.↗
DOE OSTI2024

Massive all-atom analysis of 2D materials with quantum properties (Final report)

Improvements in microscopy have enabled the acquisition of data at a scale that is difficult to process manually, making automated machine learning approaches to analyzing experimental images essential. In this project, we developed and applied machine learning (ML) workflows for atomic resolution scanning transmission electron microscopy (STEM) images. This development included improving both methodology as well as generating user-friendly codes. We developed machine learning architectures which, after training, automatically identify the location and types of defects throughout a material. We used these data to produce class-averaged images of 2D atomic coordinates with up to 0.3 pm precision, uncovering the structure and oscillations of long-range strain fields around point defects in WSe 2-2x Te 2x . We also resolved a long-standing problem in this field in the training of ML models, a lack of labeled experimental data, by developing a cycle-GAN that transformed simulated-generated labeled data into labeled data indistinguishable from experiment and therefore suitable for training. This removed the remaining parts of the ML data processing workflow where human intervention was still critical and therefore a bottleneck to working at scale. Codes have been developed and released for this full machine learning workflow. ML approaches to partially automate STEM acquisition were also developed. Finally we applied ML and other advanced data processing methods to several materials science problems in two-dimensional materials, including studying the evolution of hyperuniformity with defect concentration in WSe2, understanding phase transformations in transition metal dichalcogenides during in-situ heating in the STEM, and exploring how 2D interfaces transform from twisted into aligned structures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1973

Management of natural resources through automatic cartographic inventory

The author has identified the following significant results. Significant results of the ARNICA program (February - December 1973) were: (1) The quantitative processing of ERTS-1 data was developed along two lines: the study of geological structures and lineaments of Spanish Catalonia, and the phytogeographical study of the forest region of the Landes of Gascony (France). In both cases it is shown that the ERTS-1 imagery can be used in establishing zonings of equal quantitative interpretation value. (2) In keeping with the operational transfer program proposed in previous reports between exploration of the imagery and charting of the object, a precise data processing method was developed, concerning more particularly the selection of digital equidensity samples computer display and rigorous referencing.

Rey, P. A.↗
NASA NTRS1976

Passive microwave mapping of ice thickness

Basic calculations are presented for evaluating the feasibility of a scanning microwave radiometer system for mapping the thickness of lake ice. An analytical model for the apparent brightness temperature as a function of ice thickness has been developed, and elaborated to include such variables as galactic and atmospheric noise, aspect angle, polarization, temperature gradient in the ice, the presence of transition layers such as snow, slush, and water, increased loss due to air inclusions in the ice layer, and the presence of multiple ice thicknesses within the antenna footprint. It was found that brightness temperature measurements at six or seven frequencies in the range of 0.4 to 0.7 GHz were required to obtain unambiquous thickness estimates. A number of data processing methods were examined. The effects of antenna beamwidth, scanning rate, receiver bandwidth, noise figure, and integration time were studied.

Apinis, J. J.↗
NASA NTRS1978

Viking gas chromatograph-mass spectrometer

The Mars Viking gas chromatograph-mass spectrometer is described. The system is designed to determine the composition of the Martian atmosphere and detect and identify chemical compounds vaporized or pyrolyzed from the Martian soil. Construction details, performance data, data processing methods, and references to manufacturing and test procedures are also provided.

Rushneck, D. R.↗
NASA NTRS1978

The Ten-Ecosystem Study - Landsat ADP mapping of forest and rangeland in the United States

The Ten-Ecosystem Study was designed to assess the maximum information content of Landsat data and its utility for large area classification using a uniform technical approach on the 10 generalized forest and rangeland ecosystems of the United States. Conclusions on the feasibility of using Landsat remote sensing automatic data processing methods, selecting the best seasons, analyzing costs and the effects of site complexity, miscellaneous analysis, problems, and recommendations were derived from 2 years of study, the project being three-fourths completed.

Kan, E. P.↗
NASA NTRS1984

Pressure filtration of ceramic pastes. 4: Treatment of experimental data

The use of data processing method based on the algorithm proposed by Kalman and its application to the filtration process at constant pressure are described, as well as the advantages of this method. This technique is compared to the least squares method. The operation allows the precise parameter adjustment of the equation in direct relationship to the specific resistance of the cake.

Torrecillas, A. S.↗
NASA NTRS1988

Estimating aircraft SAR response characteristics and approximating ocean wave spectra in the Labrador Sea

The data processing methods employed to compute estimates of two-dimensional wave height-variance spectra from the ocean imagery obtained in the Labrador Sea by a C-band airborne SAR system are described. The SAR spectra are compared for high and low altitude geometries with large and small elevation angles. A surface contour radar and a radar ocean wave spectrometer aboard an aircraft are used to verify the surface wave spectrum.

Tilley, D. G.↗
NASA NTRS1989

Validation of satellite solar occultation measurements 1975-1988

The Stratospheric Aerosol and Gas Experiment (SAGE II) is discussed. SAGE II was launched from the Space Shuttle in October, 1984 as part of the Earth Radiation Budget satellite and uses the solar occultation technique to measure the extinction of solar radiation caused by the earth's atmosphere. The solar radiance data are compared with data from ground-based systems, airborne missions, balloonborne in situ measurements, ancillary measurements, and other satellite systems. The SAGE II instrument, data processing methods, and correlative measurements program are examined.

Maddrea, G. L., Jr.↗
NASA NTRS1988

A study of rain effects on radar scattering from water waves

Results are presented from a laboratory investigation of microwave power return due to rain-generated short waves on a wind wave surface. The wind wave tank, sensor, and data processing methods used in the study are described. The study focuses on the response of a 36-GHz radar system, orientated 30 deg from nadir and pointing upwind, to surface waves generated by various combinations of rain and wind. The results show stronger radar signal levels due to short surface waves generated by rain impacting the wind wave surface, supporting the results of Moore et al. (1979) for a 14-GHz radar.

Bliven, Larry F.↗
NASA NTRS1989

Hypersonic nozzle design

Possible experimental facilities appropriate to a university environment that could make meaningful contributions to the solution of problems in hypersonic aerodynamics are investigated. Needs for the National Aerospace Plane and interplanetary flights with atmospheric aerobraking are used to scope the problem. Relevant events of the past two decades in universities and at the national laboratories are examined for their implications regarding both problems and prospects. Most striking is the emergence of computational fluid dynamics, which is viewed here as an equal partner with laboratory experimentation and flight test in relating theory with reality. Also significant are major advances in instrumentation and data processing methods, especially optical techniques. The direction of the study was guided by the concept of a companion program, i.e., the university effort should complement a major area of endeavor at NASA-Langley. Through this, both faculty and student participants gain a natural and effective working relationship. Existing and proposed major hypersonic aerodynamic facilities in industry and at the national laboratories are examined by type; hypersonic wind tunnels, arc-heated tunnels, shock tubes and tunnels, and ballistic ranges. Of these, the free piston tunnel and shock tube/tunnel are most appropriate for a university.

Griffith, Wayland C.↗