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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 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Computer-aided light sheet flow visualization using photogrammetry

A computer-aided flow visualization process has been developed to analyze video images acquired from rotating and translating light sheet visualization systems. The computer process integrates a mathematical model for image reconstruction, advanced computer graphics concepts, and digital image processing to provide a quantitative and a visual analysis capability. The image reconstruction model, based on photogrammetry, uses knowledge of the camera and light sheet locations and orientations to project two-dimensional light sheet video images into three-dimensional space. A sophisticated computer visualization package, commonly used to analyze computational fluid dynamics (CFD) results, was chosen to interactively display the reconstructed light sheet images with the numerical surface geometry for the model or aircraft under study. The photogrammetric reconstruction technique and the image processing and computer graphics techniques and equipment are described. Results of the computer-aided process applied to both a wind tunnel translating light sheet experiment and an in-flight rotating light sheet experiment are presented. The capability to compare reconstructed experimental light sheet images with CFD solutions in the same graphics environment is also demonstrated.

Stacy, Kathryn↗
NASA NTRS1994

Dante's Volcano

This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

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NASA NTRS1994

Performance of customized DCT quantization tables on scientific data

We show that it is desirable to use data-specific or customized quantization tables for scaling the spatial frequency coefficients obtained using the Discrete Cosine Transform (DCT). DCT is widely used for image and video compression (MP89, PM93) but applications typically use default quantization matrices. Using actual scientific data gathered from divers sources such as spacecrafts and electron-microscopes, we show that the default compression/quality tradeoffs can be significantly improved upon by using customized tables. We also show that significant improvements are possible for the standard test images Lena and Baboon. This work is part of an effort to develop a practical scheme for optimizing quantization matrices for any given image or video stream, under any given quality or compression constraints.

Ratnakar, Viresh↗
NASA NTRS1994

Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6

The present study examines the wind-tunnel blockage and actuation systems effectiveness in starting and forcibly unstarting a two-dimensional scramjet inlet in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; however, prior to the design and fabrication of an expensive, instrumented wind-tunnel model, it was deemed necessary first to examine potential wind-tunnel blockage issues related to model sizing and to examine the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure; schlieren video was used to identify inlet start and unstart. A chronology of each actuation sequence is provided in tabular form along with still frames from the schlieren video. A pitot probe monitored the freestream conditions throughout the start/unstart process to determine if there was a blockage effect due to the model start or unstart. Because the purpose of this report is to make the phase I (blockage and actuation systems) data rapidly available to the community, the data is presented largely without analysis of the internal shock interactions or the unstart process. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

Holland, Scott D.↗
NASA NTRS1994

Two-Dimensional Scramjet Inlet Unstart Model: Wind-Tunnel Blockage and Actuation Systems Test

This supplement to NASA TM 109152 shows the Schlieren video (10 min. 52 sec., color, Beta and VHS) of the external flow field and a portion of the internal flow field of a two-dimensional scramjet inlet model in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; this (phase I) effort examines potential wind-tunnel blockage issues related to model sizing and the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure. In the video, flow is from right to left, and the inlet is oriented inverted with respect to flight, i.e., with the cowl on top. The plug motion is obvious because the plug is visible in the aft window. The cowl motion, however, is not as obvious because the cowl is hidden from view by the inlet sidewall. The end of the cowl actuator arm, however, becomes visible above the inlet sidewalls between the windows when the cowl is up (see figure 1b of the primary document). The model is injected into the tunnel and observed though several actuation sequences with two plug configurations over a range of unit freestream Reynolds number at a nominal freestream Mach number of 6. The framing rate and shutter speed of the camera were too slow to fully capture the dynamics of the unstart but did prove sufficient to identify inlet start and unstart. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

Holland, Scott D.↗
NASA NTRS1994

Virtual reality and telerobotics applications of an Address Recalculation Pipeline

The technology described in this paper was designed to reduce latency to user interactions in immersive virtual reality environments. It is also ideally suited to telerobotic applications such as interaction with remote robotic manipulators in space or in deep sea operations. in such circumstances the significant latency is observed response to user stimulus which is due to communications delays, and the disturbing jerkiness due to low and unpredictable frame rates on compressed video user feedback or computationally limited virtual worlds, can be masked by our techniques. The user is provided with highly responsive visual feedback independent of communication or computational delays in providing physical video feedback or in rendering virtual world images. Virtual and physical environments can be combined seamlessly using these techniques.

Regan, Matthew↗
NASA NTRS1994

SSME propellant path leak detection real-time

Included are four documents that outline the technical aspects of the research performed on NASA Grant NAG8-140: 'A System for Sequential Step Detection with Application to Video Image Processing'; 'Leak Detection from the SSME Using Sequential Image Processing'; 'Digital Image Processor Specifications for Real-Time SSME Leak Detection'; and 'A Color Change Detection System for Video Signals with Applications to Spectral Analysis of Rocket Engine Plumes'.

Crawford, R. A.↗
NASA NTRS1994

The probability of flaw detection and the probability of false calls in nondestructive evaluation equipment

The space industry has developed many composite materials that have high durability in proportion to their weights. Many of these materials have a likelihood for flaws that is higher than in traditional metals. There are also coverings (such as paint) that develop flaws that may adversely affect the performance of the system in which they are used. Therefore there is a need to monitor the soundness of composite structures. To meet this monitoring need, many nondestructive evaluation (NDE) systems have been developed. An NDE system is designed to detect material flaws and make flaw measurements without destroying the inspected item. Also, the detection operation is expected to be performed in a rapid manner in a field or production environment. Some of the most recent video-based NDE methodologies are shearography, holography, thermography, and video image correlation.

Temple, Enoch C.↗
NASA NTRS1994

Fracture behavior of large-scale thin-sheet aluminum alloy

A series of fracture tests on large-scale, pre-cracked, aluminum alloy panels is being carried out to examine and to characterize the process by which cracks propagate and link up in this material. Extended grips and test fixtures were specially designed to enable the panel specimens to be loaded in tension, in a 1780-kN-capacity universal testing machine. Twelve panel specimens, each consisting of a single sheet of bare 2024-T3 aluminum alloy, 3988 mm high, 2286 mm wide, and 1.016 mm thick are being fabricated with simulated through-cracks oriented horizontally at mid-height. Using existing information, a test matrix has been set up that explores regions of failure that are controlled by fracture mechanics, with additional tests near the boundary between plastic collapse and fracture. In addition, a variety of multiple site damage (MSD) configurations have been included to distinguish between various proposed linkage mechanisms. All tests but one use anti-buckling guides. At this writing seven specimens have been tested. Three were fabricated with a single central crack, three others had multiple cracks on each side of the central crack, and one had a single crack but no anti-buckling guides. Each fracture event was recorded on film, video, computer, magnetic tape, and occasionally optical microscopy. The visual showed the crack tip with a load meter in the field of view, using motion picture film for one tip and SVHS video tape for the other. The computer recorded the output of the testing machine load cell, the stroke, and twelve strain gages at 1.5 second intervals. A wideband FM magnetic tape recorder was used to record data from the same sources. The data were analyzed by two different procedures: (1) the plastic zone model based on the residual strength diagram; and (2) the R-curve. The first three tests were used to determine the basic material properties, and these results were then used in the analysis of the two subsequent tests with MSD cracks. There is good agreement between measured values and results obtained from the model.

Dewit, Roland↗
NASA NTRS1995

STS 63 Flight Day 4 Highlights/MIR-Shuttle Rendezvous

STS 63 Flight, day 4, the MIR-Shuttle rendezvous is highlighted in this video. The six-member team in the Shuttle are introduced and discuss their functions and tests for this day of the flight. There is actual footage of earth from space, of the MIR Space Station, a tour of the Shuttle cockpit, some footage from the MIR of the Space Shuttle, and footage from inside the MIR with the cosmonauts. Mission control communications with the Shuttle, communication between the Shuttle and MIR, and an historic communication between the Shuttle's astronauts and President Bill Clinton are included. President Clinton interviews each of the six-member team and discusses the upcoming space walk by Dr. Bernard Harris, the first black astronaut to walk in space. This video was recorded on February 6, 1995.

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NASA NTRS1992

Hey! What's Space Station Freedom?

This video, 'Hey! What's Space Station Freedom?', has been produced as a classroom tool geared toward middle school children. There are three segments to this video. Segment One is a message to teachers presented by Dr. Jeannine Duane, New Jersey, 'Teacher in Space'. Segment Two is a brief Social Studies section and features a series of Presidential Announcements by President John F. Kennedy (May 1961), President Ronald Reagan (July 1982), and President George Bush (July 1989). These historical announcements are speeches concerning the present and future objectives of the United States' space programs. In the last segment, Charlie Walker, former Space Shuttle astronaut, teaches a group of middle school children, through models, computer animation, and actual footage, what Space Station Freedom is, who is involved in its construction, how it is to be built, what each of the modules on the station is for, and how long and in what sequence this construction will occur. There is a brief animation segment where, through the use of cartoons, the children fly up to Space Station Freedom as astronauts, perform several experiments and are given a tour of the station, and fly back to Earth. Space Station Freedom will take four years to build and will have three lab modules, one from ESA and another from Japan, and one habitation module for the astronauts to live in.

Vonehrenfried, Dutch↗
NASA NTRS1993

Toys in Space, 2

In this educational video from the 'Liftoff to Learning' series, astronauts from the STS-54 Mission (Mario Runco, John Casper, Don McMonagle, Susan Helms, and Greg Harbaugh) explain how microgravity and weightlessness in space affects motion by using both mechanical and nonmechanical toys (gravitrons, slinkys, dart boards, magnetic marbles, and others). The gravitational effects on rotation, force, acceleration, magnetism, magnetic fields, center of axis, and velocity are actively demonstrated using these toys through experiments onboard the STS-54 Mission flight as a part of their spaceborne experiment payload. [Resource Guide referenced in the video is not available.]

Herbert, Dexter↗
NASA NTRS1994

Applications drivers for data parking on the Information Superhighway

As the cost of data storage continues to decline (currently about one-millionth of its cost four decades ago) entirely new applications areas become economically feasible. Many of these new areas involved the extraordinarily high data rates and universal connectivity soon to be provided by the National Information Infrastructure (NII). The commonly held belief is that the main driver for the NII will be entertainment applications. We believe that entertainment applications as currently touted (multi-media, 500 video channels, video-on-demand, etc.) will play an important but far from dominant role in the development of the NII and its data storage components. The most pervasively effective drivers will be medical applications such as telemedicine and remote diagnosis, education and environmental monitoring. These applications have a significant funding base and offer a clearly perceived opportunity to improve the nation's standard of living. The NII's wideband connectivity both nationwide and worldwide requires a broad spectrum of data storage devices with a wide-range of performance capabilities. These storage centers will be dispersed throughout the system. Magnetic recording devices will fill the majority of these new data storage requirements for at least the rest of this century. The storage needs of various application areas and their respective market sizes will be explored. The comparative performance of various magnetic technologies and competitive alternative storage systems will be discussed.

Johnson, Clark E., Jr.↗
NASA NTRS1991

Collection of Magellan Venus Radar Mapping Results

Through computer animation several geological features of Venus are presented in this video. The Sif Mons, a 1.2 mile high volcano and the Gula Mons, a 1.8 mile high volcano are shown. Also, radar images of a rift valley, several impact craters, and a corona can be seen. The video ends with a northeast view of Eistla Regio.

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NASA NTRS1995

STS-71 Shuttle/Mir Flight: Day 7

Day 7 of the STS-71 mission is featured in this video, a continuation from days 1-6, this video includes live footage onboard the STS-71 Space Station Atlantis and the Mir Space Station. Astronaut, Dr. Norman Thagard, after living in space for 3 months onboard the Mir Space Station, joins the crew of Atlantis for his trip back to earth. Live interviews are conducted with the crew of Atlantis.

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NASA NTRS1995

STS-71 Shuttle/Mir Flight: Day 8

Day 8 of the STS-71 mission is featured in this video, a continuation from days 1-7, this video includes live footage onboard the STS-71 Space Shuttle Atlantis and the Mir Space Station. Live interviews are conducted with the crew of Atlantis. Views are shown of the Mir Space Station from various angles.

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NASA NTRS1995

STS-71 Shuttle/Mir Flight: Day 9

Day 9 of the STS-71 mission is featured in this video, a continuation from days 1-8, this video includes live footage onboard the STS-71 Space Shuttle Atlantis and the Mir Space Station. Views are shown of the Mir Space Station from various angles and its earth orbit after disconnection from Atlantis.

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NASA NTRS1984

Twenty-Five Years of Progress. Part 1: Birth of NASA. Part 2: The Moon-A Goal

Historical footage (1958 - 1983) concerning NASA's Space Program, is reviewed in this two-part video. Host, Lynn Bondurant describes the birth of NASA and its accomplishments through the years. Part one contains: the launch of Russian satellite Sputnik on October 4,1957; the first dog (Soviet) in space; NACA Space Research, Explorer-6; and still photographs of various Space projects. Tiros 1 experimental weather satellite, Microgravity simulators, Echo 1 passive communications satellite, and the first U.S. manned spaceflight Mercury are included in part two. The seven Mercury astronauts are: Captain Donald Slayton, Lt. Commander Alan Shepard, Lt. Commander Walter Schirra, Captain Virgil Grissom, Lt. Col. John Glenn Jr., Captain Leroy Cooper Jr, and Lt. Malcolm Scott Carpenter. Also included are an ongoing interview (throughout the video) with NASA's first Administrator Keith Glennan, the first flight in 1961 with Enos, a chimpanzee, President Kennedy's speech in Washington about the Space Program, Project Gemini - the 2-manned space flights, and the recovery of Virgil Grissom from splash down.

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