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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Lab-Scale Demonstration of Pipeline Third-Party Damage Classification Using Convolutional Neural Networks

This research aims to mitigate the challenges of field tests for classification of third-party damages by generating a dataset of third-party damage events on a laboratory scale utilizing single mode-multi mode-single mode (SMS) fiber acoustic sensor. The sound samples representative of various third-party activities, such as vehicle movements, excavation, and digging, were sourced from open-source databases. These samples were then played through a speaker in proximity to an SMS sensor, and the resultant fiber acoustic vibration data were recorded for each event. This process yielded a collection of 200 samples across 13 distinct third-party events. Convolutional Neural Networks (CNNs) were employed to classify these samples into their respective categories, and an accuracy exceeding 97% was obtained from our results.

Bukka, Sandeep Reddy↗
NASA NTRS2021

GRACE Follow-On Early In-Flight Challenges

The Gravity Recovery and Climate Experiment (GRACE) Follow-On Mission is a successor to the highly successful GRACE Mission, which operated from 2002-2017. It is a partnership between the National Aeronautics and Space Administration (NASA) and the German Research Center for Geosciences, GeoForschungsZentrum Potsdam (GFZ). Under this partnership, the United States provides the project management, satellites and instruments, Germany provides the launch and mission operations. The partners share responsibilities for producing science data products. GRACE Follow-On, like its predecessor GRACE, consists of twin satellites which fly in a tandem formation at a near polar orbit separated by about 200 km along track. The mission continues the work of GRACE by tracking the movement of water, observing changes in ice sheets and sea level to provide a unique view of Earth’s changing climate. The satellites were launched May 22, 2018 from Vandenberg Air Force Base, in California, on a SpaceX Falcon 9 Rocket. Launch and Early Operations (LEOP) were completed within the first week and on-orbit commissioning proceeded for the next 8 months. The GRACE Follow-On mission is designed to last five years. The mission operations team has had to address several technical challenges early into the planned five-year mission life. The commissioning period was extended by 5 months to successfully address these issues, making it possible for the mission to meet key requirements for delivery and quality of the science data products. This paper will address the challenges faced by GRACE Follow-On and the actions taken by the mission operations team to continue to safely operate the mission.

Witkowski, M.M.↗
NASA NTRS2017

Experimental Study of Convective Heating on the Back Face and Payload of a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Aeroshell

A wind tunnel test program has been conducted to define convective heating environments on the back-face of a Hypersonic Inflatable Aerodynamic Decelerator aeroshell. Wind tunnel testing was conducted at Mach 6 and Mach 10 at unit Reynolds numbers from 0.5×10(exp 6)/ft to 3.9×10(exp 6)/ft on a 6.3088 in diameter aeroshell model. Global heating data were obtained through phosphor thermography on the aeroshell back face, as well as on the payload and the aeroshell front face. For all test conditions, laminar flow was produced on the aeroshell front face, while the separated wake shear layer and aeroshell back-face boundary layer were transitional or turbulent. Along the leeward centerline of the aeroshell back face and payload centerbody, heating levels increased with both free stream Reynolds number and angle of attack. The Reynolds number dependency was due to increasing strength of wake turbulence with Reynolds number. The angle-of-attack dependency was due to movement of the wake-vortex reattachment point on the aeroshell back face. The maximum heating levels on the aeroshell back face and payload were approximately 5% to 6%, respectively, of the aeroshell front-face stagnation point. To allow for extrapolation of the ground test data to flight conditions, the back face and payload heating levels were correlated as a function of aeroshell front-face peak momentum thickness Reynolds numbers.

Hollis, Brian R.↗
NASA NTRS2001

Planning of reach-and-grasp movements: effects of validity and type of object information

Individuals are assumed to plan reach-and-grasp movements by using two separate processes. In 1 of the processes, extrinsic (direction, distance) object information is used in planning the movement of the arm that transports the hand to the target location (transport planning); whereas in the other, intrinsic (shape) object information is used in planning the preshaping of the hand and the grasping of the target object (manipulation planning). In 2 experiments, the authors used primes to provide information to participants (N = 5, Experiment 1; N = 6, Experiment 2) about extrinsic and intrinsic object properties. The validity of the prime information was systematically varied. The primes were succeeded by a cue, which always correctly identified the location and shape of the target object. Reaction times were recorded. Four models of transport and manipulation planning were tested. The only model that was consistent with the data was 1 in which arm transport and object manipulation planning were postulated to be independent processes that operate partially in parallel. The authors suggest that the processes involved in motor planning before execution are primarily concerned with the geometric aspects of the upcoming movement but not with the temporal details of its execution.

Cues↗
NASA NTRS1973

Sea-surface circulation, sediment transport, and marine mammal distribution, Alaska continental shelf

The author has identified the following significant results. Even though nonsynchronous, the ERTS-1 imagery of November 4, 1972, showed a striking similarity to the ground truth data obtained in late August and September, 1972. The comparison of the images with ground truth data revealed that the general water circulation pattern in Lower Cook Inlet is consistent through the Fall season and that ERTS-1 images in MSS bands 4 and 5 are capable of delineating water masses with a suspended load as low as 1 mg/liter. The ERTS-1 data and the ground truth data demonstrate clearly that the coriolis effect dominates circulation in Lower Cook Inlet. The configuration of plumes in Nushagak and Kuskokwim bays further indicates the influence of the coriolis effect on the movement of sea water at high latitudes. Comparison of MSS bands 4, 5, 6, and 7 suggest MSS-1 penetration of several meters into the water column. Sea ice analysis of available imagery was exceptionally rewarding. The imagery provided a rapid method to delineate and describe the ice types apparent in the photos. The ice types ranged from newly formed grease ice to heavy flows of disintegrating shore-fast ice. Sea ice maps showing the extent of different ice zones in the Chukchi Sea are being compiled.

Wright, F. F.↗
NASA NTRS1977

Video simulator with electronic ranging

Gimbal orientation, raster shrinkage and deflection, and track movement are used to simulate attitude and range. Key component in system is video digitizer that converts vidicon camera signal to digital form, processes it to reduce image size, and reconverts processed data to analog signal for display on cathode ray tube.

Kraemer, W.↗
NASA NTRS1986

Use of speckle for determining the response characteristics of Doppler imaging radars

An optical model is developed for imaging optical radars such as the SAR on Seasat and the Shuttle Imaging Radar (SIR-B) by analyzing the Doppler shift of individual speckles in the image. The signal received at the spacecraft is treated in terms of a Fresnel-Kirchhoff integration over all backscattered radiation within a Huygen aperture at the earth. Account is taken of the movement of the spacecraft along the orbital path between emission and reception. The individual points are described by integration of the point source amplitude with a Green's function scattering kernel. Doppler data at each point furnishes the coordinates for visual representations. A Rayleigh-Poisson model of the surface scattering characteristics is used with Monte Carlo methods to generate simulations of Doppler radar speckle that compare well with Seasat SAR data SIR-B data.

Tilley, D. G.↗
NASA NTRS1993

Diffusion in liquid state and solidification of binary system (M-7)

Diffusion is one of the most fundamental physical phenomena. It relates to the manufacturing of almost all materials. Therefore, the precise knowledge of diffusivities of relevant materials is necessary for the optimization of these processes. On the other hand, such knowledge is indispensable to understanding the diffusion mechanism and structure of liquid metal in the field of physical metallurgy. Many diffusion experiments on solid metal were undertaken and a lot of data were accumulated. But on liquid metals there are few measurements because of experimental difficulties, such as thermal convection, induced by very slight temperature gradients in the specimen. Under microgravity conditions, the movement of liquid metal due to density differences and thermal convection must be suppressed markedly. Therefore, the transportation process will be controlled only by the diffusion of constituent atoms. These conditions offer the optimum environments for the diffusion experiment. The experiments are briefly described. Diffusion couples are prepared by attaching end to end two rods of different pure metals using hot press equipment. These couples are inserted into a graphite crucible and then doubly enclosed by two silica ampoules, respectively. The specimen is inserted into a tantalum cartridge, which is welded in a vacuum using an electron-beam apparatus. These cartridges are charged in the continuous heating furnace in space and held at a given temperature for a predetermined time and then solidified. The concentration distribution of elements in these specimens will be measured along the rod axis by means of an electron probe microanalyzer. The counterdiffusivity of the liquid metal binary system is determined on the basis of the compensated concentration distribution profile for thermal contraction.

Dan, T.↗
NASA NTRS1995

Psychophysical evaluation of three-dimensional auditory displays

This report describes the progress made during the first year of a three-year cooperative research agreement (CRA NCC2-542). The CRA proposed a program of applied psychophysical research designed to determine the requirements and limitations of three-dimensional (3-D) auditory display systems. These displays present synthesized stimuli to a pilot or virtual workstation operator that evoke auditory images at predetermined positions in space. The images can be either stationary or moving. In previous years, we completed a number of studies that provided data on listeners' abilities to localize stationary sound sources with 3-D displays. the current focus is on the use of 3-D displays in 'natural' listening conditions, which include listeners' head movements, moving sources, multiple sources and 'echoic' sources. The results of our research on two of these topics, the role of head movements and the role of echoes and reflections, were reported in the most recent semi-annual progress report (Appendix A). In the period since the last progress report we have been studying a third topic, the localizability of moving sources. The results of this research are described.

Wightman, Frederic L.↗
NASA NTRS1996

Psychophysical Evaluation of Three-Dimensional Auditory Displays

This report describes the progress made during the second year of a three-year Cooperative Research Agreement. The CRA proposed a program of applied psychophysical research designed to determine the requirements and limitations of three-dimensional (3-D) auditory display systems. These displays present synthesized stimuli to a pilot or virtual workstation operator that evoke auditory images at predetermined positions in space. The images can be either stationary or moving. In previous years, we completed a number of studies that provided data on listeners' abilities to localize stationary sound sources with 3-D displays. The current focus is on the use of 3-D displays in 'natural' listening conditions, which include listeners'head movements, moving sources, multiple sources and 'echoic' sources. The results of our research on one of these topics, the localization of multiple sources, was reported in the most recent Semi-Annual Progress Report (Appendix A). That same progress report described work on two related topics, the influence of a listener's a-priori knowledge of source characteristics and the discriminability of real and virtual sources. In the period since the last Progress Report we have conducted several new studies to evaluate the effectiveness of a new and simpler method for measuring the HRTF's that are used to synthesize virtual sources and have expanded our studies of multiple sources. The results of this research are described below.

Wightman, Frederic L.↗
NASA NTRS1995

Psychophysical Evaluation of Three-Dimensional Auditory Displays

This report describes the process made during the first year of a three-year Cooperative Research Agreement (CRA NCC2-542). The CRA proposed a program of applied of psychophysical research designed to determine the requirements and limitations of three-dimensional (3-D) auditory display systems. These displays present synthesized stimuli to a pilot or virtual workstation operator that evoke auditory images at predetermined positions in space. The images can be either stationary or moving. In previous years. we completed a number of studies that provided data on listeners' abilities to localize stationary sound sources with 3-D displays. The current focus is on the use of 3-D displays in 'natural' listening conditions, which include listeners' head movements, moving sources, multiple sources and 'echoic' sources. The results of our research on two of these topics, the role of head movements and the role of echoes and reflections, were reported in the most recent Semi-Annual Pro-ress Report (Appendix A). In the period since the last Progress Report we have been studying a third topic, the localizability of moving sources. The results of this research are described. The fidelity of a virtual auditory display is critically dependent on precise measurement of the listener''s Head-Related Transfer Functions (HRTFs), which are used to produce the virtual auditory images. We continue to explore methods for improving our HRTF measurement technique. During this reporting period we compared HRTFs measured using our standard open-canal probe tube technique and HRTFs measured with the closed-canal insert microphones from the Crystal River Engineering Snapshot system.

Wightman, Frederic L.↗
NASA NTRS2000

Case Study Analyses of the SUCCESS DC-8 Scanning Lidar Database

Under project SUCCESS (Subsonic Aircraft Contrail and Cloud Effects Special Study) funded by the Atmospheric Effects of Aviation Program, SRI International (SRI) developed an angular scanning backscatter lidar for operation on the NASA DC-8 research aircraft and deployed the scanning lidar during the SUCCESS field campaign. The primary purpose of the lidar was to generate real-time video displays of clouds and contrails above, ahead of, and below the DC-8 as a means to help position the aircraft for optimum cloud and contrail sampling by onboard in situ sensors, and to help extend the geometrical domain of the in situ sampling records. A large, relatively complex lidar database was collected and several data examples were processed to illustrate the value of the lidar data for interpreting the other data records collected during SUCCESS. These data examples were used to develop a journal publication for the special SUCCESS Geophysical Research Letters issue. The data examples justified data analyses of a larger part of the DC-8 lidar database and is the objective of the current study. Efficient processing of the SUCCESS DC-8 scanning lidar database required substantial effort to enhance hardware and software components of the data system that was used for the initial analyses. MATLAB instructions are used to generate altitude and distance color-coded lidar displays corrected for effects introduced by aircraft pitch and forward movement during an angular scan time interval. Onboard in situ sensor atmospheric measurements are propagated to distances ahead of the DC-8 using recorded aircraft velocity so that they can be plotted on the lidar displays for comparison with lidar remotely observed aerosol distributions. Resulting lidar and in situ sensor polar scan displays over extended sampling intervals are integrated into a time series movie format for 36 case studies. Contrails and clouds were detected to ranges of 15 km by the forward-viewing angular scanning lidar and were progressively mapped as the aircraft approached and penetrated them. Near aircraft lidar observations were much better correlated with in situ sensor observations than lidar observations at greater distances ahead of the aircraft. The major cause of this difference was thought to be the about 2 deg. offset of the lidar viewing direction from the flight direction. Contrail spatial distributions were not of the quality obtainable from ground-based lidar observations. This results because contrails tend to become horizontally stratified, vertical distance between angular lidar observations increases with increased distance from the aircraft, and erratic aircraft motions during an angular scan. The most useful lidar observations were made with lidar viewing directions of vertically upward or vertically downward. These provided real-time information on aircraft altitudes to achieve optimum in situ cloud and contrail sampling. At sampling altitudes, the forward viewing angular scanning observations were useful for fine-tuning the aircraft altitude for cloud and contrail penetration. Best information on cloud and contrail properties were obtained from vertically directed lidar observations as the aircraft performed a series of upward and downward penetrations of contrails. This operational mode was especially well suited for lidar and radiometric evaluation of cloud and contrail optical and radiative properties. The vertical viewing lidar detected ice crystals thought to be precipitating from an aircraft contrail and their scavenging by a cirrus cloud layer. The lidar display indicates that the crystals are effective for increasing cirrus cloud density. Vertical angular scanning observations can evaluate the sharp decrease in lidar backscatter for small off-vertical viewing directions that result from horizontally aligned ice crystals and perhaps can provide additional information on crystal shapes. The about 2 deg. offset of the lidar viewing direction from the flight direction is thought to have greatly degraded the forward-viewing angular scanning observations and this mode of operation was not fully evaluated. However, the reasoning for this capability remains valid and the angular scan presentations collected during this program justifies modification of the lidar pod for true forward direction lidar viewing during future cloud and contrail studies.

Uthe, Edward E.↗
NASA NTRS2003

The potato virus X TGBp2 protein association with the endoplasmic reticulum plays a role in but is not sufficient for viral cell-to-cell movement

Potato virus X (PVX) TGBp1, TGBp2, TGBp3, and coat protein are required for virus cell-to-cell movement. Plasmids expressing GFP fused to TGBp2 were bombarded to leaf epidermal cells and GFP:TGBp2 moved cell to cell in Nicotiana benthamiana leaves but not in Nicotiana tabacum leaves. GFP:TGBp2 movement was observed in TGBp1-transgenic N. tabacum, indicating that TGBp2 requires TGBp1 to promote its movement in N. tabacum. In this study, GFP:TGBp2 was detected in a polygonal pattern that resembles the endoplasmic reticulum (ER) network. Amino acid sequence analysis revealed TGBp2 has two putative transmembrane domains. Two mutations separately introduced into the coding sequences encompassing the putative transmembrane domains within the GFP:TGBp2 plasmids and PVX genome, disrupted membrane binding of GFP:TGBp2, inhibited GFP:TGBp2 movement in N. benthamiana and TGBp1-expressing N. tabacum, and inhibited PVX movement. A third mutation, lying outside the transmembrane domains, had no effect on GFP:TGBp2 ER association or movement in N. benthamiana but inhibited GFP:TGBp2 movement in TGBp1-expressing N. tabacum and PVX movement in either Nicotiana species. Thus, ER association of TGBp2 may be required but not be sufficient for virus movement. TGBp2 likely provides an activity for PVX movement beyond ER association.

NASA Discipline Plant Biology↗
NASA NTRS2004

Probe Station Antenna Range

This summer I was given the task of programming a Probe Station to collect near field antenna patterns and convert them to far field patterns. The purpose of this project is to provide NASA with another means of antenna characterizing. Currently, NASA Glenn can measure near field and far field patterns of many different types of antennas. The antennas targeted for this lab are small patch antennas at high frequencies that require probe biasing. The Probe Station contains two probes for RF signals and another two for DC Biasing. The way this lab works is as follows: A patch antenna is placed on the probe station and biased properly for testing. This antenna is known as the Antenna Under Test (AUT). The AUT is supplied with an RF signal from a probe that is connected to a network analyzer. Above the AUT hangs a probe for measuring the electric field emitted by the AUT. The probe is controlled by four axis. The axis of movements for this probe are back and forth, left and right, up and down, and rotation. The network analyzer and axis controllers are tied into a computer for reading commands and recording data. The probe scans a rectangular pattern above the AUT to measure the electric field emitted by the AUT. This data is then recorded and analyzed back at the computer.

Zaman, Afroz↗
NASA NTRS2008

NASA's Earth Science Use of Commercially Availiable Remote Sensing Datasets: Cover Image

The cover image incorporates high resolution stereo pairs acquired from the DigitalGlobe(R) QuickBird sensor. It shows a digital elevation model of Meteor Crater, Arizona at approximately 1.3 meter point-spacing. Image analysts used the Leica Photogrammetry Suite to produce the DEM. The outside portion was computed from two QuickBird panchromatic scenes acquired October 2006, while an Optech laser scan dataset was used for the crater s interior elevations. The crater s terrain model and image drape were created in a NASA Constellation Program project focused on simulating lunar surface environments for prototyping and testing lunar surface mission analysis and planning tools. This work exemplifies NASA s Scientific Data Purchase legacy and commercial high resolution imagery applications, as scientists use commercial high resolution data to examine lunar analog Earth landscapes for advanced planning and trade studies for future lunar surface activities. Other applications include landscape dynamics related to volcanism, hydrologic events, climate change, and ice movement.

Underwood, Lauren W.↗
NASA NTRS1978

The gravity method and interpretive techniques for detecting vertical crustal movements

Observations of temporal variations of gravity can be used as an inexpensive and rapid means of detecting, monitoring, and studying crustal deformation associated with many active geological processes. Such observations can yield qualitative or semiquantitative information on elevation changes and, when combined with independent elevation data, can yield information about changes of the subsurface density field arising from both subsurface displacements and temporal variations of the density of materials in the subsurface. The effectiveness of gravity techniques in specific cases of crustal deformation depends on the configuration of the local gravity field, the physical processes involved in the deformation, and the accuracy with which temporal gravity variations can be measured.

Jachens, R. C.↗
DOE OSTI2026

2011-2012 Maryland Route 200 Travel Survey

The 2011-2012 Maryland Route 200 Travel Survey collected in-vehicle global positioning system (GPS) data to investigate the use of Maryland Route 200, also known as the Intercounty Connector. The University of Maryland conducted the survey between October 2011 and February 2012 in Washington, D.C., and Baltimore, Maryland. Its goal was to increase understanding of the potential use of Maryland Route 200, a tolled freeway connecting Maryland's Montgomery County and Prince George's County. Dedicated in-vehicle GPS devices were installed in 260 vehicles to record location information every 60 seconds if movement was detected. Survey subjects partook in an initial participation form as well as a recall survey, providing social demographic information and a one-day travel diary.

1Hz data↗