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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 1,099 records · Page 61
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NASA NTRS1998

Feasibility Investigation on the Development of a Structural Damage Diagnostic and Monitoring System for Rocket Engines

The research activity for this project is mainly to investigate the necessity and feasibility to develop a structural health monitoring system for rocket engines, and to carry out a research plan for further development of the system. More than one hundred technical papers have been searched and reviewed during the period. We concluded after this investigation that adding a new module in NASA's existing automated diagnostic system to monitor the healthy condition of rocket engine structures is a crucial task, and it's possible to develop such a system based upon the vibrational-based nondestructive damage assessment techniques. A number of such techniques have been introduced. Their advantages and disadvantages are also discussed. A global research plan has been figured out. As the first step of the overall research plan, a proposal for the next fiscal year has been submitted.

Shen, Ji Y.↗
NASA NTRS1998

Simultaneous in situ Optical Monitoring Techniques during Crystal Growth of ZnSe by Physical Vapor Transport

ZnSe crystals grown in sealed ampoules by the physical vapor transport method were monitored in situ using three techniques, simultaneously. A Michelson interferometer was set-up to observe the growth rate and surface morphological evolution. An interference pattern (interferogram) is formed by the interaction between the reflection of a HeNe laser (632.8 nm wavelength) off the crystal-vapor interface and a reference beam from the same laser. Preliminary results indicate that the rate of growth/thermal-etching can be calculated using analog data acquisition and simple fringe counting techniques. Gross surface features may also be observed using a digital frame grabber and fringe analysis software. The second in situ technique uses optical absorption to determine the partial pressures of the vapor species. The Se2 and Zn vapor species present in the sealed ampoule absorb light at characteristic wavelengths. The optical absorption is determined by monitoring the light intensity difference between the sample and reference beams. The Se2 Partial pressure profile along the length of the ampoule was estimated from the vibronic absorption peaks at 340.5, 350.8, 361.3 and 379.2 nm using the Beer's law constants established in the calibration runs of pure Se. Finally, because the high temperature crystal growth furnace contains windows, in situ visual observation of the growing crystal is also possible. The use of these techniques not only permits in situ investigation of high temperature vapor growth of semiconductors, but also offers the potential for real time feed back on the growing crystal and allows the possibility of actively controlling the growth process.

Su, C.- H.↗
NASA NTRS1999

A New ERA in Global Temperature Monitoring with the Advanced Microwave Sounding Unit (AMSU)

The launch of the first Advanced Microwave Sounding Unit (AMSU) on the NOAA-15 spacecraft on 13 May 1998 marked a significant advance in our ability to monitor global temperatures. Compared to the Microwave Sounding Units (MSU) flying since 1978 on the TIROS-N series of NOAA polar orbiters, the AMSU offers better horizontal, vertical, and radiometric resolutions. It will allow routine monitoring of 1 1 (mostly) separate layers, compared to 2 or 3 with the MSU, including layers in the middle and upper stratosphere (2.5 hPa) where increasing carbon dioxide concentrations should be causing a cooling rate of about 1 deg. C per decade. More precise limb corrections combined with low noise will allow identification of subtle spatial temperature patterns associated with global cyclone activity.

Spencer, Roy W.↗
NASA NTRS1999

Long-Term Hard X-Ray Monitoring of X-Ray Bursters

The scientific goal of this project was to monitor a selected sample of x-ray bursters using data from the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory to characterize the hard x-ray emission of these objects over long time intervals. The project was closely related to "Monitoring x-ray emission from x-ray bursters", NASA project, and "Hard x-ray emission of x-ray bursters", NASA project, and shares publications in common with both of these. These efforts have lead to results directly from the BATSE data and also from Target of Opportunity Observations (TOO) made with the Rossi X-Ray Timing Explorer based on detection of transient hard x-ray outbursts with BATSE. The following papers have used BATSE data or data obtained with BATSE TOO triggers.

Halpern, Jules P.↗
NASA NTRS1999

Condition Monitoring of Large-Scale Facilities

This document provides a summary of the research conducted for the NASA Ames Research Center under grant NAG2-1182 (Condition-Based Monitoring of Large-Scale Facilities). The information includes copies of view graphs presented at NASA Ames in the final Workshop (held during December of 1998), as well as a copy of a technical report provided to the COTR (Dr. Anne Patterson-Hine) subsequent to the workshop. The material describes the experimental design, collection of data, and analysis results associated with monitoring the health of large-scale facilities. In addition to this material, a copy of the Pennsylvania State University Applied Research Laboratory data fusion visual programming tool kit was also provided to NASA Ames researchers.

Hall, David L.↗
NASA NTRS1997

Environmental Assessment and Monitoring with ICAMS (Image Characterization and Modeling System) Using Multiscale Remote-Sensing Data

With the rapid increase in spatial data, especially in the NASA-EOS (Earth Observing System) era, it is necessary to develop efficient and innovative tools to handle and analyze these data so that environmental conditions can be assessed and monitored. A main difficulty facing geographers and environmental scientists in environmental assessment and measurement is that spatial analytical tools are not easily accessible. We have recently developed a remote sensing/GIS software module called Image Characterization and Modeling System (ICAMS) to provide specialized spatial analytical tools for the measurement and characterization of satellite and other forms of spatial data. ICAMS runs on both the Intergraph-MGE and Arc/info UNIX and Windows-NT platforms. The main techniques in ICAMS include fractal measurement methods, variogram analysis, spatial autocorrelation statistics, textural measures, aggregation techniques, normalized difference vegetation index (NDVI), and delineation of land/water and vegetated/non-vegetated boundaries. In this paper, we demonstrate the main applications of ICAMS on the Intergraph-MGE platform using Landsat Thematic Mapper images from the city of Lake Charles, Louisiana. While the utilities of ICAMS' spatial measurement methods (e.g., fractal indices) in assessing environmental conditions remain to be researched, making the software available to a wider scientific community can permit the techniques in ICAMS to be evaluated and used for a diversity of applications. The findings from these various studies should lead to improved algorithms and more reliable models for environmental assessment and monitoring.

Lam, N.↗
NASA NTRS1996

Contributions of the SSBUV Experiment to Long-Term Ozone Monitoring

The SSBUV experiment flew eight Space Shuttle missions from October 1989 to January 1996 in conducted eight missions between October 1989 and support of the US long-term ozone monitoring program. Contributions of the SSBUV experiment are reviewed in this paper. SSBUV data are being used to provide and validate the absolute and long-term calibrations of multiple satellite-based ozone monitoring instruments. SSBUV observed a significant decrease in Northern hemisphere total ozone from the winter of 1992 to the following winter, and SSBUV data were combined with Nimbus-7 data to assess long-term ozone changes during the 1980's. SSBUV solar irradiance measurements are being used to determine the absolute solar spectral irradiance in the middle UV, validate solar data from two UARS instruments, and independently measure long-term solar change at wavelengths important for ozone photochemistry. SSBUV data where also used to study the effects of surface reflectivity and rotational Raman scattering on the ozone retrievals, determine the NO column amount and its altitude distribution, measure the UV lunar albedo, and assist in the optimization of wavelengths for new instruments.

Hilsenrath, E.↗
NASA NTRS1998

Monitoring Oceanic Islands Via Radarsat Imaging Radar

Oceanic islands represent an often overlooked aspect of the land surface of Earth, yet they are sensitive, natural laboratories for investigating the impacts of environmental change on landscapes and land-cover systems. For this reason, we have utilized the Canadian Space Agency's RADARSAT satellite to initiate a program for monitoring the landscapes of approximately 20 oceanic islands as part of the RADARSAT Background Mission. To date, we have analyzed high resolution SAR images of 12 islands that extend from the Arctic, throughout the Atlantic and Southern Indian oceans, and into the equatorial Pacific. We have selected islands for monitoring on the basis of their known or suspected history of landscape change in association with environmental factors or anthropogenic effects.

Garvin, James B.↗
NASA NTRS1971

A Pilot System for Environmental Monitoring Through Domestic Animals

A pilot system for environmental monitoring is in its early phases of development in Northern California. It is based upon the existing nation wide Federal-State Market Cattle Testing (14CT) program for brucellosis in cattle. This latter program depends upon the collection of blood program at the time of identified cattle. As the cattle Population of California is broadly distributed throughout the state, we intend to utilize these blood samples to biologically monitor the distribution and intensity of selected environmental pollutants. In a 2-year preliminary trial, the feasibility of retrieving, utilizing for a purpose similar to this, and tracing back to their geographic areas of origin of MCT samples have been demonstrated.

Schwabe, Calvin W.↗
NASA NTRS1971

Beta Absorption Mass Monitoring of Particulates - A Review

The theory and application of beta-radiation absorption for the measurement and monitoring of airborne particulates are discussed. The use of this technique, both for source testing and for ambient air quality monitoring is reviewed. Various particle collection methods used in conjunction with beta absorption sensing configurations are considered. State of the art and current developments of instrumentation approaches for the automated measurement of mass concentration and size distribution of aerosols by beta absorption are discussed. Methods for electronic signal processing and recording are presented. The Beta absorption technique appears as a powerful tool for the unattended measurement of the mass of particulate pollution, compatible with telemetry and central data processing methods.

Lilienfeld, Pedro↗
NASA NTRS1971

The Role of Monitoring in Controlling Water Pollution

The purpose of this paper is to provide an overview of trends in the national water pollution control effort and to describe the role of monitoring in that effort, particularly in relation to the responsibilities of the Environmental Protection Agency (EPA). I hope the paper will serve as a useful framework for the more specific discussions of monitoring technology to follow.

Hirsch, Allan↗
NASA NTRS1999

Science Data Report for the Optical Properties Monitor (OPM) Experiment

Long term stability of spacecraft materials when exposed to the space environment continues to be a major area of investigation. The natural and induced environment surrounding a spacecraft can decrease material performance and limit useful lifetimes. The Optical Properties Monitor (OPM) experiment provided the capability to perform the important flight testing of materials and was flown on the Russian Mir Station to study the long term effects of the natural and induced space environment on materials. The core of the OPM in-flight analysis was three independent optical instruments. These instruments included an integrating sphere spectral reflectometer, a vacuum ultraviolet spectrometer, and a Total Integrated Scatter instrument. The OPM also monitored selected components of the environment including molecular contamination. The OPM was exposed on the exterior of the Mir Docking Module for approximately 8-1/2 months. This report describes the OPM experiment, a brief background of its development, program organization, experiment description, mission overview including space environment definition, performance overview, materials data including flight and ground data, in-depth post flight analysis including ground analysis measurements and a summary discussion of the findings and results.

Wilkes, Donald R.↗
NASA NTRS2000

Commercialization and Industrial Development for the Fetal Hear Rate Monitor

The primary objectives for this task were to continue the development and testing of the NASA/ODU passive acoustic fetal heart rate monitor, with the goal of transferring the technology to the commercial sector. Areas of work included: 1. To assist in the development of a new hardware front end electronics box for the fetal heart rate monitor, so as to reduce the size of the electronics box, and also to provide for a "low-frequency" and "high-frequency" mode of operation. To make necessary changes in the operating software to support the two modes of operation. 2. To provide an option for a strip chart recording for the system, so that medical personnel could more easily make comparisons with ultra sound strip chart recordings. and 3. To help with continued testing of the system.

Zahorian, Stephen↗
NASA NTRS1998

Monitoring X-Ray Emission from X-Ray Bursters

The goal of this investigation was to use the All-Sky Monitor on the Rossi X-Ray Timing Explorer (RXTE) in combination with the Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory to simultaneously measure the x-ray (2-12 keV) and hard x-ray (20-100 keV) emission from x-ray bursters. The investigation was successful. We made the first simultaneous measurement of hard and soft x-ray emission and found a strong anticorrelation of hard and soft x-ray emission from the X-Ray Burster 4U 0614+091. The monitoring performed under this investigation was also important in triggering target of opportunity observations of x-ray bursters made under the investigation hard x-ray emission of x-ray bursters approved for RXTE cycles 1 and 2. These observations lead to a number of papers on high-frequency quasi-periodic oscillations and on hard x-ray emission from the x-ray bursters 4U 0614+091 and 4U 1705-44.

Kaaret, Philip↗
NASA NTRS1999

Six Years of Short-Spaced Monitoring of the v=1 and v=2 J=1-0 (28)SiO Maser Emission in Evolved Stars

We present the results from a monitoring of the v=1 and v=2 J=1-0 (28)SiO maser emission in 21 objects, covering all types of known SiO maser emitters: 13 Mira variables, 2 long period semiregulars (SRGs), 3 variable supergiants (SGs), 2 OH/IR stars, and one young stellar object. This study has been carried out with the 13.7 meter radiotelescope of the Centro Astronomico de Yebes (Guadalajara, Spain), from July 1984 to May 1990, and represents the longest and most tightly sampled monitoring of SiO masers ever published. Our data show that for Mira-type (i.e. regular) variables, the SiO and optical light curves agree in period, and that the maxima of the SiO emission lag the optical ones by about 0.1-0.2 periods. Since a similar lag characterizes the near infrared (NIR) emission variability from these stars, we conclude that for regular variables SiO and NIR vary in phase. This result was confirmed in three objects for which NIR variability curves are available. For SRGs and SGs, we found a less systematic behavior, but when the SiO emission is periodic, its variability curve agrees with the optical one, also showing a lag between maximum epochs similar to that of Mira-type stars. The data clearly reveal other interesting details on the SiO maser variability, such as the strong intensity differences between different maxima and changes in the velocity distribution of the emission. Finally, the SiO masers associated to the young stellar object Orion IRc2 showed a double peaked spectrum with low amplitude, aperiodic variations.

Alcolea, J.↗
NASA NTRS1998

A Discussion of Issues in Integrity Constraint Monitoring

In the development of large-scale software systems, analysts, designers, and programmers identify properties of data objects in the system. The ability to check those assertions during runtime is desirable as a means of verifying the integrity of the program. Typically, programmers ensure the satisfaction of such properties through the use of some form of manually embedded assertion check. The disadvantage to this approach is that these assertions become entangled within the program code. The goal of the research is to develop an integrity constraint monitoring mechanism whereby a repository of software system properties (called integrity constraints) are automatically inserted into the program by the mechanism to check for incorrect program behaviors. Such a mechanism would overcome many of the deficiencies of manually embedded assertion checks. This paper gives an overview of the preliminary work performed toward this goal. The manual instrumentation of constraint checking on a series of test programs is discussed, This review then is used as the basis for a discussion of issues to be considered in developing an automated integrity constraint monitor.

Fernandez, Francisco G.↗
NASA NTRS2000

Comparison of Pilots' Situational Awareness While Monitoring Autoland Approaches Using Conventional and Advanced Flight Display Formats

A simulation experiment was performed to assess situation awareness (SA) and workload of pilots while monitoring simulated autoland operations in Instrument Meteorological Conditions with three advanced display concepts: two enhanced electronic flight information system (EFIS)-type display concepts and one totally synthetic, integrated pictorial display concept. Each concept incorporated sensor-derived wireframe runway and iconic depictions of sensor-detected traffic in different locations on the display media. Various scenarios, involving conflicting traffic situation assessments, main display failures, and navigation/autopilot system errors, were used to assess the pilots' SA and workload during autoland approaches with the display concepts. From the results, for each scenario, the integrated pictorial display concept provided the pilots with statistically equivalent or substantially improved SA over the other display concepts. In addition to increased SA, subjective rankings indicated that the pictorial concept offered reductions in overall pilot workload (in both mean ranking and spread) over the two enhanced EFIS-type display concepts. Out of the display concepts flown, the pilots ranked the pictorial concept as the display that was easiest to use to maintain situational awareness, to monitor an autoland approach, to interpret information from the runway and obstacle detecting sensor systems, and to make the decision to go around.

Kramer, Lynda J.↗
NASA NTRS1999

VSOP Monitoring of the Quasar 1928+738

One limitation of the VSOP (VLBI Space Observatory Program) mission is that several famous superluminal sources such as 3C273 cannot be monitored with good uv-coverage throughout the lifetime of the VSOP Mission at regular intervals that are spaced closely enough to follow the evolution in the fine-scale source-structure. The reason for this is that the HALCA spacecraft cannot#observe sources outside certain restricted ranges of sun angle, defined to be the time variable angle between the source and the sun. However sources that lie within 10 degrees of the ecliptic poles can be observed throughout the year and observations are not restricted to narrow temporal windows. Furthermore, the best ground-based uv-coverages are obtained for circumpolar sources and consequently these will be the sources for which the maximum amount of space VLBI data will be obtained with a given ground array. We have began a VSOP monitoring campaign at 5 GHz on the relatively low redshift (z=0.3) superluminal quasar 1928+738 which is both a circumpolar source and lies 10 degrees away from the ecliptic pole. 1928+738 is in the S5 polar cap sample and has been well studied both on the arsecond-scale and mas-scale. 22 GHz observations have shown that the motion of the VLBI components in 1928+738 is inconsistent with simple linear expansion along a fixed position angle (PA) for all components. Indeed, 1928+738 was one of the first sources for which helical jet motion was proposed and it has been further proposed that a massive binary black hole (MBBH) system is responsible for the sinusoidal jet ridge line observed at 22 GHz over a S year period. our VSOP observations are designed to check this proposal.

Murphy, D. W.↗