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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Producing Global Science Products for the Moderate Resolution Imaging Spectroradiometer (MODIS) in MODAPS

The MODerate resolution Imaging Spectroradiometer (MODIS) was launched on NASA's EOS-Terra spacecraft December 1999. With 36 spectral bands covering the visible, near wave and short wave infrared. MODIS produces over 40 global science data products, including sea surface temperature, ocean color, cloud properties, vegetation indices land surface temperature and land cover change. The MODIS Data Processing System (MODAPS) produces 400 GB/day of global MODIS science products from calibrated radiances generated in the Earth Observing System Data and Information System (EOSDIS). The science products are shipped to the EOSDIS for archiving and distribution to the public. An additional 200 GB of products are shipped each day to MODIS team members for quality assurance and validation of their products. In the sections that follow, we will describe the architecture of the MODAPS, identify processing bottlenecks encountered in scaling MODAPS from 50 GB/day backup system to a 400 GB/day production system and discuss how these were handled.

Masuoka, Edward J.↗
NASA NTRSDate not supplied

A PPE Use Case on Configuration Management Approach for MBSE

Systems engineers worldwide have been working to implement Model-based Systems Engineering (MBSE) environments, tools, and methodologies. MBSE is a formalized application of modeling to support systems engineering, including requirements, design, analysis, verification, and validation activities over the project’s lifecycle[1]; MBSE captures the system data into a digital environment. Significant benefits of MBSE includes a reduction in the time in performing systems engineering activities and an improvement higher fidelity data production. As more Systems Engineers are using MBSE, the models it produces are becoming the source of truth for Systems Engineering artifacts. As we move towards using these models as the source of truth, a more rigorous Configuration Management (CM) infrastructure is needed. Many of the MBSE tools provide CM options but utilizing them efficiently and effectively can be challenging. More rigorous methods and tools are needed to assist with keeping track of changes in the model, making sure inadvertent changes to baseline data did not occur, visibility of changes in the different model versions, and the impacts of changes to the models. System engineers and configuration management personnel from the Power and Propulsion Element (PPE) project at NASA Glenn Research Center have been working to develop a modeling construct that allows models to be the source of truth and maintain a configuration managed baseline. This paper presents a process that leverages the existing CM tools and describes how PPE used this process to manage changes more rigorously. It will describe the process behind building the model architecture that utilizes the MBSE tool capabilities and the configuration management process. It will contain some of the advantages and disadvantages of the architecture that the PPE project had settled upon utilizing, as well as some enhanced capabilities that the PPE MBSE team has developed.

MBSE↗
NASA NTRS1997

Earth Radiation Budget Experiment (ERBE) Data Sets for Global Environment and Climate Change Studies

For a number of years there has been considerable interest in the earth's radiation budget (ERB) or energy balance, and entails making the best measurements possible of absorbed solar radiation, reflected shortwave radiation (RSW), thermal outgoing longwave radiation (OLR), and net radiation. ERB data are fundamental to the development of realistic climate models and studying natural and anthropogenic perturbations of the climate. Much of the interest and investigations in the earth's energy balance predated the age of earth-orbiting satellites (Hunt et al., 1986). Beginning in the mid 1960's earth-orbiting satellites began to play an important role in making measurements of the earth's radiation flux although much effort had gone into measuring ERB parameters prior to 1960 (House et al., 1986). Beginning in 1974 and extending until the present time, three different satellite experiments (not all operating at the same time) have been making radiation budget measurements almost continually in time. Two of the experiments were totally dedicated to making radiation budget measurements of the earth, and the other experiment flown on NOAA sun-synchronous AVHRR weather satellites produced radiation budget parameters as a by-product. The heat budget data from the AVHRR satellites began collecting data in June 1974 and have operated almost continuously for 23 years producing valuable data for long term climate monitoring.

Bess, T. Dale↗
NASA NTRS1985

Estimating the change in asymptotic direction due to secular changes in the geomagnetic field

The concept of geomagnetic optics, as described by the asymptotic directions of approach, is extremely useful in the analysis of cosmic radiation data. However, when changes in cutoff occur as a result of evolution in the geomagnetic field, there are corresponding changes in the asymptotic cones of acceptance. A method is introduced of estimating the change in the asymptotic direction of approach for vertically incident cosmic ray particles from a reference set of directions at a specific epoch by considering the change in the geomagnetic cutoff.

Flueckiger, E. O.↗
NASA NTRS1978

Variation of solar cell sensitivity and solar radiation on tilted surfaces

The validity is studied that one of various insolation models used to compute solar radiation incident on tilted surfaces from global data measured on horizontal surfaces. The variation of solar cell sensitivity to solar radiation is determined over a wide range of atmospheric condition. A new model was formulated that reduced the deviations between measured and predicted insolation to less than 3 percent. Evaluation of solar cell sensitivity data indicates small change (2-3 percent) in sensitivity from winter to summer for tilted cells. The feasibility of using such global data as a means for calibrating terrestrial solar cells is discussed.

Klucher, T. M.↗
NASA NTRS1988

Effect of 0.1 at. pct Zirconium on the cyclic oxidation resistance of beta-NiAl

The effect of 0.1 at. pct Zr on the cyclic oxidation of hipped beta-NiAl was studied. Oxidation testing was performed in static air at 1100-1200 C, using 1-hr exposure cycles for test times up to 3000 hr. The weight change versus time data were modeled with the COSP computer program to analyze and predict cyclic-oxidation behavior. Zr additions significantly change the nature of the scale-spalling process during cooling, so that the oxide spalls near the oxide-air interface at a relatively low depth within the scale. Without Zr, the predominantly alpha-Al2O3 scale tends to spall randomly to bare metal at relatively high effective-scale-loss rates, particularly at 1150 C and 1200 C. This leads to higher rates of Al consumption for the Zr-free aluminide and much earlier depletion of Al, leading to eventual breakaway (i.e., failure).

Barrett, Charles A.↗
NASA NTRS1991

Atlas of wide-field-of-view outgoing longwave radiation derived from Nimbus 7 Earth radiation budget data set, November 1985 to October 1987

An atlas of monthly outgoing longwave radiation global contour maps and associated spherical harmonic coefficients is presented. The atlas contains 23 months of data from November 1985 to October 1987 . The data were derived from the second Earth Radiation Budget (ERB) package, which was flown on the Nimbus 7 Sun-synchronous satellite in 1987. This data set is a companion set and extension to similar atlases that documented 10 years of outgoing longwave radiation results from Nimbus 6 and Nimbus 7 satellites. This atlas and the companion atlases give a data set covering a 12-year time period and will be very useful in studying different aspects of our changing climate. The data set also provides a 3-year overlap with the current Earth Radiation Budget Experiment (ERBE).

Bess, T. Dale↗
NASA NTRS2006

Identifying Trends in Deep Space Network Monitor Data

A computer program has been developed that analyzes Deep Space Network monitor data, looking for changes of trends in critical parameters. This program represents a significant improvement over the previous practice of manually plotting data and visually inspecting the resulting graphs to identify trends. This program uses proven numerical techniques to identify trends. When a statistically significant trend is detected, then it is characterized by means of a symbol that can be used by pre-existing model-based reasoning software. The program can perform any of the following functions: Given an expectation that data in a given list should exhibit an upward, downward, constant, or unknown trend, it can determine whether the data do or do not follow such a trend. Given a list of data, it can identify which of the aforementioned trends the data follow. Given two lists of data, it can determine whether or not both follow the same trend. This program can be executed on a variety of computers. It can be distributed in either source code or binary code form. It must be run in conjunction with any one of a number of Lisp compilers that are available commercially or as shareware.

James, Mark↗
NASA NTRS1978

LANDSAT image differencing as an automated land cover change detection technique

Image differencing was investigated as a technique for use with LANDSAT digital data to delineate areas of land cover change in an urban environment. LANDSAT data collected in April 1973 and April 1975 for Austin, Texas, were geometrically corrected and precisely registered to United States Geological Survey 7.5-minute quadrangle maps. At each pixel location reflectance values for the corresponding bands were subtracted to produce four difference images. Areas of major reflectance differences are isolated by thresholding each of the difference images. The resulting images are combined to obtain an image data set to total change. These areas of reflectance differences were found, in general, to correspond to areas of land cover change. Information on areas of land cover change was incorporated into a procedure to mask out all nonchange areas and perform an unsupervised classification only for data in the change areas. This procedure identified three broad categories: (1) areas of high reflectance (construction or extractive), (2) changes in agricultural areas, and (3) areas of confusion between agricultural and other areas.

Stauffer, M. L.↗
NASA NTRS2005

Evaluation of Decision Trees for Cloud Detection from AVHRR Data

Automated cloud detection and tracking is an important step in assessing changes in radiation budgets associated with global climate change via remote sensing. Data products based on satellite imagery are available to the scientific community for studying trends in the Earth's atmosphere. The data products include pixel-based cloud masks that assign cloud-cover classifications to pixels. Many cloud-mask algorithms have the form of decision trees. The decision trees employ sequential tests that scientists designed based on empirical astrophysics studies and simulations. Limitations of existing cloud masks restrict our ability to accurately track changes in cloud patterns over time. In a previous study we compared automatically learned decision trees to cloud masks included in Advanced Very High Resolution Radiometer (AVHRR) data products from the year 2000. In this paper we report the replication of the study for five-year data, and for a gold standard based on surface observations performed by scientists at weather stations in the British Islands. For our sample data, the accuracy of automatically learned decision trees was greater than the accuracy of the cloud masks p < 0.001.

AVHRR (ADVANCED VERY HIGH RESOLUTION RADIOMETER)↗
NASA NTRS1994

Automated protein crystal growth facility

A customer for the protein crystal growth facility fills the specially designed chamber with the correct solutions, fills the syringes with their quenching solutions, and submits the data needed for the proper growth of their crystal. To make sure that the chambers and syringes are filled correctly, a NASA representative may assist the customer. The data needed is the approximate growth time, the growth temperature, and the desired crystal size, but this data can be changed anytime from the ground, if needed. The chambers are gathered and placed into numbered slots in special drawers. Then, data is entered into a computer for each of the chambers. Technicians map out when each chamber's growth should be activated so that all of the chambers have enough time to grow. All of this data is up-linked to the space station when the previous growth session is over. Anti-vibrational containers need to be constructed for the high forces encountered during the lift off and the landing of the space shuttle, and though our team has not designed these containers, we do not feel that there is any reason why a suitable one could not be made. When the shuttle reaches the space station, an astronaut removes a drawer of quenched chambers from the growth facility and inserts a drawer of new chambers. All twelve of the drawers can be replaced in this fashion. The optical disks can also be removed this way. The old drawers are stored for the trip back to earth. Once inside the growth facility, a chamber is removed by the robot and placed in one of 144 active sites at a time previously picked by a technician. Growth begins when the chamber is inserted into an active site. Then, the sensing system starts to determine the size of the protein crystal. All during the crystal's growth, the customer can view the crystal and read all of the crystal's data, such as growth rate and crystal size. When the sensing system determines that the crystal has reached the predetermined size, the robot is told to pick up a syringe filled with the correct quenchant solution and inject it into the chamber to stop the crystal growth. The chamber is then removed from the active site and placed into its original storage slot. Another chamber is then placed into the active site and the process is repeated in all of the active sites until all of the chambers have complted their growth. After ninety days (the scheduled time between shuttle visits), the crystal growth is completed, and the old drawers are replaced with new ones. Once the customer extracts the crystals, the chambers are retrieved for future customers.

Donald, Stacey↗
NASA NTRS2003

Data Assimilation Office (DAO) Operational Analyses and Reanalyses for Coordinated Enhanced Observing Period (CEOP)

The DAO operational assimilation system has produced and archived gridded data since 1998, and will continue through the CEOP period. However, major system upgrades and new assimilation variables will significantly affect the surface energy balance and data product. These changes will be discussed and the prospects for a CEOP reanalysis will be presented. W e will also review the data currently available and describe how to access the data.

Bosilovich, M.↗
NASA NTRS1979

Senescent changes in the ribosomes of animal cells in vivo and in vitro

The paper examines RNA-ribosomal changes observed in protozoa and fixed postmitotic cells, as well as the characteristics of intermitotic cells. Attention is given to a discussion of the implications of the reported ribosomal changes as to the senescent deterioration of protein synthesis and physiological functions. A survey of the literature suggests that, while the data on ribosomal change in dividing cells both in vivo and in vitro are inconclusive, there is strong histological and biochemical evidence in favor of some degree of quantitative ribosomal loss in fixed postmitotic cells. Since these decreases in ribosomes are demonstrated in differential cells from nematodes, insects and mammals, they may represent a universal manifestation of cytoplasmic senescence in certain types of fixed postmitotic animal cells. The observed variability in ribosomal loss for cells belonging to the same type suggests that this involution phenomenon is rather related to the wear and tear suffered by a particular cell.

Miquel, J.↗
NASA NTRS2014

Landsat-8 Thermal Infrared Sensor (TIRS) Vicarious Radiometric Calibration

Launched in February 2013, the Landsat-8 carries on-board the Thermal Infrared Sensor (TIRS), a two-band thermal pushbroom imager, to maintain the thermal imaging capability of the Landsat program. The TIRS bands are centered at roughly 10.9 and 12 micrometers (Bands 10 and 11 respectively). They have 100 m spatial resolution and image coincidently with the Operational Land Imager (OLI), also on-board Landsat-8. The TIRS instrument has an internal calibration system consisting of a variable temperature blackbody and a special viewport with which it can see deep space; a two point calibration can be performed twice an orbit. Immediately after launch, a rigorous vicarious calibration program was started to validate the absolute calibration of the system. The two vicarious calibration teams, NASA/Jet Propulsion Laboratory (JPL) and the Rochester Institute of Technology (RIT), both make use of buoys deployed on large water bodies as the primary monitoring technique. RIT took advantage of cross-calibration opportunity soon after launch when Landsat-8 and Landsat-7 were imaging the same targets within a few minutes of each other to perform a validation of the absolute calibration. Terra MODIS is also being used for regular monitoring of the TIRS absolute calibration. The buoy initial results showed a large error in both bands, 0.29 and 0.51 W/sq m·sr·micrometers or -2.1 K and -4.4 K at 300 K in Band 10 and 11 respectively, where TIRS data was too hot. A calibration update was recommended for both bands to correct for a bias error and was implemented on 3 February 2014 in the USGS/EROS processing system, but the residual variability is still larger than desired for both bands (0.12 and 0.2 W/sq m·sr·micrometers or 0.87 and 1.67 K at 300 K). Additional work has uncovered the source of the calibration error: out-of-field stray light. While analysis continues to characterize the stray light contribution, the vicarious calibration work proceeds. The additional data have not changed the statistical assessment but indicate that the correction (particularly in band 11) is probably only valid for a subset of data. While the stray light effect is small enough in Band 10 to make the data useful across a wide array of applications, the effect in Band 11 is larger and the vicarious results suggest that Band 11 data should not be used where absolute calibration is required.

TIIRS↗
NASA NTRS2020

Empirical estimates of regional carbon budgets imply reduced global soil heterotrophic respiration

Resolving regional carbon budgets is critical for informing land-based mitigation policy. For nine regions covering nearly the whole globe, we collected inventory estimates of carbon-stock changes complemented by satellite estimates of biomass changes where inventory data are missing. The net land–atmospheric carbon exchange (NEE) was calculated by taking the sum of the carbon-stock change and lateral carbon fluxes from crop and wood trade, and riverine-carbon export to the ocean. Summing up NEE from all regions, we obtained a global ‘bottom-up’ NEE for net land anthropogenic CO2 uptake of –2.2±0.6 PgC/yr consistent with the independent top-down NEE from the global atmospheric carbon budget during 2000–2009. This estimate is so far the most comprehensive global bottom-up carbon budget accounting, which set up an important milestone for global carbon-cycle studies. By decomposing NEE into component fluxes, we found that global soil heterotrophic respiration amounts to a source of CO2 of 39 PgC/yr with an interquartile of 33–46 PgC/yr —a much smaller portion of net primary productivity than previously reported.

carbon budget↗
NASA NTRS2004

Making Antarctic Atmospheric Electricity Data Available to Living with a Star and Climate Change Investigators

This proposal requests support for making the nearly three decades of Antarctic atmospheric electricity data available to more workers. Measurements of the vertical electric field and air-earth current density made at the Earth's surface in Antarctica have recently been shown to be of considerable interest to scientists interested in monitoring short-term Sun-Earth connections and long term climate change. Such measurements have been made off and on for more than three decades, primarily at Vostok and South Pole stations. There is no single place where all of these data can be obtained via the Internet in a contemporary format. The work proposed here will attempt to remedy this deficiency as much as possible. Data we know to be presently available include data from South Pole, 1982-86 and 1991-1993, and Vostok station, 1997-present. Data were taken at South Pole and Vostok in the 60's and ~O'S, but these may prove difficult to obtain in digital form. At present, only the University of Houston's 1991-1993 data are available on the Web. Unfortunately, they are stored on a server slated for retirement. Also, they are written VAX binary floating point, using the UCLA/Stanford/Michigan flatfile format (FLATDBMS), which is obscure to some users. We propose to combine and reformat the three available data sets plus any others we can obtain onto a newer server. We will use a more common and comprehensible format. Archival copies will be burned onto CD and/or DVD-ROM media. Finally we will register these data with the appropriate NASA data systems.

Bering, Edgar↗
NASA NTRS1976

The effect of changes in the USF/NASA toxicity screening test method on data from some cellular polymers

Rankings of relative toxicity can be markedly affected by changes in test variables. Revision of the USF/NASA toxicity screening test procedure to eliminate the connecting tube and supporting floor and incorporate a 1.0 g sample weight, 200 C starting temperature, and 800 C upper limit temperature for pyrolysis, reversed the rankings of flexible polyurethane and polychloroprene foams, not only in relation to each other, but also in relation to cotton and red oak. Much of the change is attributed to reduction of the distance between the sample and the test animals, and reduction of the sample weight charged. Elimination of the connecting tube increased the relative toxicity of the polyurethane foams. The materials tested were flexible polyurethane foam, without and with fire retardant; rigid polyurethane foam with fire retardant; flexible polychloroprene foam; cotton, Douglas fir, red oak, hemlock, hardboard, particle board, polystyrene, and polymethyl methacrylate.

Hilado, C. J.↗