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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 793 records · Page 44
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NASA NTRS1995

Global tropospheric experiment at the Hong Kong Atmosphere Chemistry Measurement Station

The major activities of the Global Tropospheric Experiment at the Hong Kong Atmospheric Chemistry Measurement Station are presented for the period 1 January - 31 December 1995. Activities included data analysis, reduction, and archiving of atmospheric measurements and sampling. Sampling included O3, CO, SO2, NO, TSP, RSP, and ozone column density. A data archive was created for the surface meteorological data. Exploratory data analysis was performed, including examination of time series, frequency distributions, diurnal variations and correlation. The major results have been or will be published in scientific journals as well as presented at conferences/workshops. Abstracts are attached.

Carroll, Mary Ann↗
NASA NTRS1996

Short-Term Chromospheric Variability in alpha Tauri (K5 III): Results from IUE Time Series Observations

We evaluate time series observations of chromospheric lines (Mg II, Mg I, and C II) for the K giant alpha Tau obtained using the IUE LWP camera at high dispersion. These observations cover a time span of about 2 weeks in 1994 February-March and were designed to resolve variations occurring within hours, days, and weeks. We consider the observational results in relation to theoretical acoustic heating models, motivated by the fact that alpha Tau may exhibit a basal (i.e., minimum) level of chromospheric activity. The data reveal flux variations between the extremes of 8% in Mg II h+k and 15% in each emission component. These variations occur on timescales as short as 8 hr but not on timescales longer than approx.3 days. For the h and k components, flux variations occurring on a timescale as short as 1.5 hr are also found. These changes are often not correlated (and are sometimes even anticorrelated), leading to remarkable differences in the h/k ratios. We argue that these results are consistent with the presence of strong acoustic shocks, which can lead to variable Mg II line emission when only a small number of strong shocks are propagating through the atmosphere. We deduce the electron density in the C II lambda 2325 line formation region to be log(base e) of N. approx. equals 9.0, in agreement with previous studies. Our data provide evidence that the Mg II basal flux limit for K giants might be a factor of 4 higher than suggested by Rutten et al.

Cuntz, Manfred↗
NASA NTRS1997

Characterization of Ionospheric Flow Patterns During Times of Unusual Auroral Activity Using DE and DMSP Data

This final report describes the work done by Dr. Marc Hairston and Dr. Rod Heelis on NASA SR&T grant NAGW-4411 studying the theta aurora using DE-1 ultraviolet imager data and DMSP particle data. This report covers the period from summer 1995 through summer 1996 along with a review of the previous work. Previous work on this grant looked at the time period from the launch of DMSP-F8 in June 1987 through the end of mission of DE-1 in summer 1991. Despite the sporadic and decreasing frequency of observations from DE-1 over this time period, we were able to identify six events for study where the DE-1 imager observed a theta aurora occurring during a period in which the DMSP-F8 satellite flew through the region of the aurora at an altitude of 800 km. We focused on the best two events where the theta aurora persisted for an extended period so that we could observe the DMSP particle signatures in both the hemisphere observed by DE-1 and in the other polar hemisphere immediately before or afterwards. These results were presented at the Fall 1994 meeting of the AGU. Initially we had hoped to expand on this work. However, further work showed that none of these events gave a clear enough signature in the DMSP data for us to identify a theta aurora in the hemisphere opposite to the hemisphere imaged by DE-1. Without that, there were no results from this work that were new enough to warrant publication. So instead we used the final year of the grant to work with our colleague, J. A. Cumnock on a similar project using DE data to study the evolution of theta auroras as a function of the IMF A paper from that work was published which acknowledged this grant and a copy of that paper is included with this final report.

Hairston, Marc↗
NASA NTRS1998

The 'CommTech' Methodology: A Demand-Driven Approach to Efficient, Productive and Measurable Technology Transfer

Market research sources were used to initially gather primary technological problems and needs data from non-aerospace companies in targeted industry sectors. The company-supplied information served as input data to activate or start-up an internal, phased match-making process. This process was based on technical-level relationship exploration followed by business-level agreement negotiations, and culminated with project management and execution. Space Act Agreements represented near-term outputs. Company product or process commercialization derived from Lewis support and measurable economic effects represented far-term outputs.

Horsham, Gray A. P.↗
NASA NTRS1998

Summer Research Internships at Biosphere 2 Center

Through the support of NASA's Mission to Planet Earth, Biosphere 2 Center hosted 10 research interns for a 10 week period during the summer of 1998. In addition, we were able to offer scholarships to 10 students for Columbia University summer field courses. Students participating in these programs were involved in numerous earth systems activities, collecting data in the field and conducting analyses in the laboratory. Students enrolled in the field program were expected to design independent research projects as part of their coursework. In addition to laboratory and field research, students participated in weekly research seminars by resident and visiting scientists. Field school students were involved in field trips exposing them to the geology and ecology of the region including Arizona Sonora Desert Museum, Mount Lemmon, Aravaipa Canyon and the Gulf of California. Interns participated in laboratory-based research. All students were expected to complete oral and written presentations of their work during the summer.

Source record↗
NASA NTRS1999

The Commtech Methodology: A Demand-Driven Approach to Efficient, Productive, and Measurable Technology Transfer and Commercialization

This paper presents a comprehensive review and assessment of a demonstration technology transfer and commercialization prouram called "CommTech". The pro-ram was conceived and initiated in early to mid-fiscal year 1995, and extended roughly three years into the future. Market research sources were used to initially gather primary technological problems and needs data from non-aerospace companies in three targeted industry sectors: environmental, surface transportation, and bioengineering. Company-supplied information served as input data to activate or start-up an internal, phased matchmaking process. This process was based on technical-level relationship exploration followed by business-level agreement negotiations. and culminated with project management and execution. Space Act Agreements represented near-term outputs. Company product or process commercialization derived from NASA Glenn support and measurable economic effects represented far-term outputs.

Horsham, Gary A. P.↗
NASA NTRS1992

Variable Property Flow in Rectangular Ducts with Repeated Rectangular Rib Roughness

PHOENICS was used to simulate turbulent flow of supercritical hydrogen through asymmetrically heated rectangular ducts with one side rib-roughened, in order to provide design data for active cooling systems of hypersonic aircraft where the hydrogen fuel is used as coolant. Variable property and conjugate heat transfer effects were considered. The computations using PHOENICS required provision of property sub-routines for supercritical hydrogen, a low-Reynolds number form of the k-epsilon turbulence model, a rough-wall wall function and a procedure for calculating proper diffusion coefficients at the fluid-solid interface. The effect of each design variable such as width and height of duct and wall thickness, on pressure drop and maximum wall temperature was investigated. PHOENICS version 1.4 was used on an IBM 3090 computer.

Youn, B.↗
NASA NTRS2000

Multi-Agent Diagnosis and Control of an Air Revitalization System for Life Support in Space

An architecture of interoperating agents has been developed to provide control and fault management for advanced life support systems in space. In this adjustable autonomy architecture, software agents coordinate with human agents and provide support in novel fault management situations. This architecture combines the Livingstone model-based mode identification and reconfiguration (MIR) system with the 3T architecture for autonomous flexible command and control. The MIR software agent performs model-based state identification and diagnosis. MIR identifies novel recovery configurations and the set of commands required for the recovery. The AZT procedural executive and the human operator use the diagnoses and recovery recommendations, and provide command sequencing. User interface extensions have been developed to support human monitoring of both AZT and MIR data and activities. This architecture has been demonstrated performing control and fault management for an oxygen production system for air revitalization in space. The software operates in a dynamic simulation testbed.

Malin, Jane T.↗
NASA NTRS2000

X-Ray Astronomy

Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

Wu, S. T.↗
NASA NTRS2000

Shuttle Radar Topography Mission (SRTM) Flight System Design and Operations Overview

This paper provides an overview of the Shuttle Radar Topography Mission (SRTM), with emphasis on flight system implementation and mission operations from systems engineering perspective. Successfully flown in February, 2000, the SRTM's primary payload consists of several subsystems to form the first spaceborne dual-frequency (C-band and X-band) fixed baseline interferometric synthetic aperture radar (InSAR) system, with the mission objective to acquire data sets over 80% of Earth's landmass for height reconstruction. The paper provides system architecture, unique design features, engineering budgets, design verification, in-flight checkout and data acquisition of the SRTM payload, in particular for the C-band system. Mission operation and post-mission data processing activities are also presented. The complexity of the SRTM as a system, the ambitious mission objective, the demanding requirements and the high interdependency between multi-disciplined subsystems posed many challenges. The engineering experience and the insight thus gained have important implications for future spaceborne interferometric SAR mission design and implementation.

Shen, Yuhsyen↗
NASA NTRS2002

A Data Miner for the Information Power Grid

Grid Miner (GM) is one of the early data mining applications developed by NASA to help users obtain information from the Information Power Grid (IPG). Topics cover include: benefits of data mining, potential use of grids in data mining activities, an overview of the GM application, and a brief review of GM architecture and implementation issues. The current status of the GM system is also discussed.

Hinke, Thomas H.↗
NASA NTRS2002

Coastal Atmosphere and Sea Time Series (CoASTS)

In this document, the first three years of a time series of bio-optical marine and atmospheric measurements are presented and analyzed. These measurements were performed from an oceanographic tower in the northern Adriatic Sea within the framework of the Coastal Atmosphere and Sea Time Series (CoASTS) project, an ocean color calibration and validation activity. The data set collected includes spectral measurements of the in-water apparent (diffuse attenuation coefficient, reflectance, Q-factor, etc.) and inherent (absorption and scattering coefficients) optical properties, as well as the concentrations of the main optical components (pigment and suspended matter concentrations). Clear seasonal patterns are exhibited by the marine quantities on which an appreciable short-term variability (on the order of a half day to one day) is superimposed. This short-term variability is well correlated with the changes in salinity at the surface resulting from the southward transport of freshwater coming from the northern rivers. Concentrations of chlorophyll alpha and total suspended matter span more than two orders of magnitude. The bio-optical characteristics of the measurement site pertain to both Case-I (about 64%) and Case-II (about 36%) waters, based on a relationship between the beam attenuation coefficient at 660nm and the chlorophyll alpha concentration. Empirical algorithms relating in-water remote sensing reflectance ratios and optical components or properties of interest (chlorophyll alpha, total suspended matter, and the diffuse attenuation coefficient) are presented.

Hooker, Stanford B.↗
NASA NTRS2003

Hypergravity Stimulates Osteoblast Proliferation Via Matrix-Integrin-Signaling Pathways

Extensive characterizations of the physiologic consequences of microgravity and gravity indicate that lack of weight-bearing may cause tissue atrophy through cellular and subcellular level mechanisms. We hypothesize that gravity is needed for the efficient transduction of cell growth and survival signals from the extra-cellular matrix (ECM) in mechanosensitive tissues. Recent work from our laboratory and from others shows that an increase of gravity increases bone cell growth and survival. We found that 50-g hypergravity stimulation increased osteoblast proliferation for cells grown on Collagen Type I and Fibronectin, but not on Laminin or uncoated plastic. This may be a tissue-specific response, because 50-g hypergravity stimulation caused no increase in proliferation for primary rat fibroblasts. These results combined with RT-PCR for all possible integrins indicate that beta1 integrin subunit may be involved. The osteoblast proliferation response on Collagen Type I was greater at 25-g than at 10-g or 50-g; 24-h duration of hypergravity was necessary to see an increase in proliferation. Survival was enhanced during hypergravity stimulation by the presence of matrix. Flow cytometry analysis indicated that cell cycle may be altered; BrdU incorporation in proliferating cells showed an increase in the number of actively dividing cells from about 60% at 1-g to over 90% at 25-g. To further investigate the molecular components involved, we applied fluorescence labeling of cytoskeletal and signaling molecules to cells after 2 to 30 minutes of hypergravity stimulation. While structural components did not appear to be altered, phosphorylation increased, indicating that signaling pathways may be activated. These data indicate that gravity mechanostimulation of osteoblast proliferation involves specific matrix-integrin signaling pathways which are sensitive to duration and g-level.

Vercoutere, W.↗
NASA NTRS1998

Antiproliferative effect of elevated glucose in human microvascular endothelial cells

Diabetic microangiopathy has been implicated as a fundamental feature of the pathological complications of diabetes including retinopathy, neuropathy, and diabetic foot ulceration. However, previous studies devoted to examining the deleterious effects of elevated glucose on the endothelium have been performed largely in primary cultured cells of macrovessel origin. Difficulty in the harvesting and maintenance of microvascular endothelial cells in culture have hindered the study of this relevant population. Therefore, the objective of this study was to characterize the effect of elevated glucose on the proliferation and involved signaling pathways of an immortalized human dermal microvascular endothelial cell line (HMEC-1) that possess similar characteristics to their in vivo counterparts. Human dermal microvascular endothelial cells (HMEC-1) were grown in the presence of normal (5 mM) or high D-glucose (20 mM) for 14 days. The proliferative response of HMEC-1 was compared under these conditions as well as the cAMP and PKC pathways by in vitro assays. Elevated glucose significantly inhibited (P < 0.05) HMEC-1 proliferation after 7, 10, and 14 days. This effect was not mimicked by 20 mM mannitol. The antiproliferative effect was more pronounced with longer exposure (1-14 days) to elevated glucose and was irreversible 4 days after a 10-day exposure. The antiproliferative effect was partially reversed in the presence of a PKA inhibitor, Rp-cAMP (10-50 microM), and/or a PKC inhibitor, Calphostin C (10 nM). HMEC-1 exposed to elevated glucose (20 mM) for 14 days caused an increase in cyclic AMP accumulation, PKA, and PKC activity but was not associated with the activation of downstream events such as CRE and AP-1 binding activity. These data support the hypothesis that HMEC-1 is a suitable model to study the deleterious effects of elevated glucose on microvascular endothelial cells. Continued studies with HMEC-1 may prove advantageous in delineation of the molecular pathophysiology associated with diabetic microangiopathy.

NASA Discipline Cell Biology↗
NASA NTRS2000

Feasibility Activities Completed for the Direct Data Distribution (D(sup )3) Experiment

The Direct Data Distribution (D(sup 3)) project being designed at the NASA Glenn Research Center at Lewis Field will demonstrate a high-performance communications system that transmits information at up to 1.2 gigabits per second (Gbps) from an advanced technology payload carried by the space shuttles in low Earth orbit to small (0.9-m) autonomously tracking terminals on the Earth. The flight communications package features a solid-state, phased-array antenna operating in the commercial K-band frequency that electronically steers two independently controlled downlink beams toward low-cost tracking ground terminals. The array enables agile, vibration-free beam steering at reduced size and weight with increased reliability over traditional mechanically steered reflectors. The flight experiment will also demonstrate efficient digital modulation technology that allows transmission of substantially increased amounts of latency-tolerant data (up to 72 Gb of data per minute of contact time) with very high quality (10(exp -11) bit error rate). D(sup 3) enables transmission from low-Earth-orbit science spacecraft, the shuttles, or the International Space Station directly to NASA field centers and principle investigator sites, or directly into the commercial terrestrial telecommunications network for remote distribution and archive. The ground terminal features a cryocooled receiver for ultralow noise and a reduced antenna aperture as well as open-loop tracking for unattended operations. The D(sup 3) technology validation and service demonstration will help to facilitate NASA's transition from using Government-owned communications assets to using commercially provided services.

Wald, Lawrence W.↗
NASA NTRS2005

Relocation of Advanced Water Vapor Radiometer 1 to Deep Space Station 55

In June of 2004, the Advanced Water Vapor Radiometer (AWVR) unit no. 1 was relocated to the Deep Space Station (DSS) 55 site in Madrid, Spain, from DSS 25 in Goldstone, California. This article summarizes the relocation activity and the subsequent operation and data acquisition. This activity also relocated the associated Microwave Temperature Profiler (MTP) and Surface Meteorology (SurfMET) package that collectively comprise the Cassini Media Calibration System (MCS).

Oswald, J.↗