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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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Dual TV monitor and collimated lens system in windscreens of standard aircraft cockpit simulator permits both pilot and copilot to simultaneously view three dimensional presentation. Proper design of complete system permits depth and viewpoint of visual displays to be accurately presented.
Direct evidence is reported for the simultaneous occurrence of Ostwald ripening and short-distance cluster mobility during annealing of discontinuous metal films on clean amorphous substrates. The annealing characteristics of very thin particulate deposits of silver on amorphized clean surfaces of single crystalline thin graphite substrates were studied by in-situ transmission electron microscopy (TEM) under controlled environmental conditions (residual gas pressure of 10 to the minus 9th power torr) in the temperature range from 25 to 450 C. Sputter cleaning of the substrate surface, metal deposition, and annealing were monitored by TEM observation. Pseudostereographic presentation of micrographs in different annealing stages, the observation of the annealing behavior at cast shadow edges, and measurements with an electronic image analyzing system were employed to aid the visual perception and the analysis of changes in deposit structure recorded during annealing. Slow Ostwald ripening was found to occur in the entire temperature range, but the overriding surface transport mechanism was short-distance cluster mobility.
The paper describes the system configuration and data manipulation capabilities of a solar image display system which allows interactive analysis of visual images and on-line manipulation of digital data. Image processing features include smoothing or filtering of images stored in the display, contrast enhancement, and blinking or flickering images. A computer with a core memory of 28,672 words provides the capacity to perform complex calculations based on stored images, including computing histograms, selecting subsets of images for further analysis, combining portions of images to produce images with physical meaning, and constructing mathematical models of features in an image. Some of the processing modes are illustrated by some image sequences from solar observations.
The microwave oceanographic satellite Seasat is described, and the main characteristics of its five sensors, including a radar altimeter, the Seasat-A scatterometer system, a synthetic aperture radar, a visual and infrared radiometer, and a scanning multichannel microwave radiometer, are discussed. Experimental programs undertaken by the satellite are briefly summarized.
Instructional material describing a methodology of remote sensing data interpretation and examples of applicatons to land use survey are presented. The image interpretation elements are discussed for different types of sensor systems: aerial photographs, radar, and MSS/LANDSAT. Visual and automatic LANDSAT image interpretation is emphasized.
A dual laser optical system and method is disclosed for visualization of phenomena in transport substances which induce refractive index gradients such as fluid flow and pressure and temperature gradients in fluids and gases. Two images representing mutually perpendicular components of refractive index gradients may be viewed simultaneously on screen. Two lasers having wave lengths in the visible range but separated by about 1000 angstroms are utilized to provide beams which are collimated into a beam containing components of the different wave lengths. The collimated beam is passed through a test volume of the transparent substance. The collimated beam is then separated into components of the different wave lengths and focused onto a pair of knife edges arranged mutually perpendicular to produce and project images onto the screen.
In order to ensure the reliable operation of the Attitude and Articulation Control Subsystem (AACS) which will guide the Galileo spacecraft on its two and one-half year journey to Jupiter, the AACS is being rigorously tested. The primary objectives of the test program are the verification of the AACS's form, fit, and function, especially with regard to subsystem external interfaces and the functional operation of the flight software. Attention is presently given to the Galileo Closed Loop Test System, which simulates the dynamic and 'visual' flight environment for AACS components in the laboratory.
A laboratory dedicated to ground based materials processing in preparation for space flight was established at the NASA Lewis Research Center. Experiments are performed to delineate the effects of gravity on processes of both scientific and commercial interest. Processes are modeled physically and mathematically. Transport model systems are used where possible to visually track convection, settling, crystal growth, phase separation, agglomeration, vapor transport, diffusive flow, and polymers reactions. The laboratory contains apparatus which functionally duplicates apparatus available for flight experiments and other pieces instrumented specifically to allow process characterization. Materials addressed include metals, alloys, salts, glasses, ceramics, and polymers. The Microgravity Materials Science Laboratory is staffed by engineers and technicians from a variety of disciplines and is open to users from industry and academia as well as the government. Examples will be given of the laboratory apparatus typical experiments and results.
Short takeoff and landing (STOL) and advanced short takeoff and vertical landing (STOVL) aircraft are being pursued for deployment near the end of this century. These concepts offer unique capabilities not seen in conventional aircraft: for example, shorter takeoff distances and the ability to operate from damaged runways and remote sites. However, special technology is critical to the development of this unique class of aircraft. Some of the real issues that are associated with these concepts are hot gas ingestion and airframe heating while in ground effects. Over the past nine years, NASA Lewis Research Center has been involved in several cooperative programs in the 9- by 15 Foot Low-Speed Wind Tunnel (LSWT) to establish a database for hot gas ingestion and airframe heating. The modifications are presented that were made in the 9- by 15-Foot LSWT, including the evolution of the ground plane, model support system, and tunnel sidewalls; and flow visualization techniques, instrumentation, test procedures, and test results. The 9- by 15-Foot LSWT tests were conducted at full scale exhaust nozzle pressure ratios. The headwind velocities varied from 8 to 120 kn depending on the concept (STOL or STOVL). Typical compressor-face distortions (pressure and temperature), ground plane contours, and model surface temperature profiles are presented.
Aerodynamic control using a rotatable, miniature nose-tip strake system was investigated in a water tunnel with a forebody model. Flow visualization and yawing moment measurements were performed. The results show that the system was highly effective in controlling the forebody vortices and producing controlled yawing moments at moderate-to-high angles of attack. In comparison with the forebody strakes used in several previous studies, the system can potentially be substantially smaller in size, simpler in operation, and effective over wide ranges of angles of attack and sideslip.
The Hybrid Automated Reliability Predictor (HARP) integrated reliability (HiREL) workstation tool system marks another step toward the goal of producing a totally integrated computer aided design (CAD) workstation design capability. Since a reliability engineer must generally graphically represent a reliability model before he can solve it, the use of a graphical input description language increases productivity and decreases the incidence of error. The captured image displayed on a cathode ray tube (CRT) screen serves as a documented copy of the model and provides the data for automatic input to the HARP reliability model solver. The introduction of dependency gates to a fault tree notation allows the modeling of very large fault tolerant system models using a concise and visually recognizable and familiar graphical language. In addition to aiding in the validation of the reliability model, the concise graphical representation presents company management, regulatory agencies, and company customers a means of expressing a complex model that is readily understandable. The graphical postprocessor computer program HARPO (HARP Output) makes it possible for reliability engineers to quickly analyze huge amounts of reliability/availability data to observe trends due to exploratory design changes.
The move to visualization and image processing in data systems is increasing the demand for larger and faster mass storage systems. The technology of choice is magnetic tape. This paper briefly reviews the technology past, present, and projected. A case is made for standards and the value of the standards to users.
The Astrophysical Information Systems Workshop was one of the three Integrated Technology Planning workshops. Its objectives were to develop an understanding of future mission requirements for information systems, the potential role of technology in meeting these requirements, and the areas in which NASA investment might have the greatest impact. Workshop participants were briefed on the astrophysical mission set with an emphasis on those missions that drive information systems technology, the existing NASA space-science operations infrastructure, and the ongoing and planned NASA information systems technology programs. Program plans and recommendations were prepared in five technical areas: Mission Planning and Operations; Space-Borne Data Processing; Space-to-Earth Communications; Science Data Systems; and Data Analysis, Integration, and Visualization.
The description, analysis, and experimental results of a method for identifying possible defects on High Temperature Reusable Surface Insulation (HRSI) of the Orbiter Thermal Protection System (TPS) is presented. Currently, a visual postflight inspection of Orbiter TPS is conducted to detect and classify defects as part of the Orbiter maintenance flow. The objective of the method is to automate the detection of defects by identifying anomalies between preflight and postflight images of TPS components. The initial version is intended to detect and label gross (greater than 0.1 inches in the smallest dimension) anomalies on HRSI components for subsequent classification by a human inspector. The approach is a modified Golden Template technique where the preflight image of a tile serves as the template against which the postflight image of the tile is compared. Candidate anomalies are selected as a result of the comparison and processed to identify true anomalies. The processing methods are developed and discussed, and the results of testing on actual and simulated tile images are presented. Solutions to the problems of brightness and spatial normalization, timely execution, and minimization of false positives are also discussed.
NTV is a tool used to visualize execution traces from message passing systems. It is designed to be ported easily to different trace formats. The first version of NTV uses trace files produced using AIMS Version 2.2. Versions for the native traces from the IBM SP2 and Intel Paragon are nearing completion. A distinctive characteristic of NTV is that it uses static displays rather then time varying displays. This, in combination with mouse controlled zooming, gives the user the ability to get a global view of the execution and a focused view of details. The principal display is a time line display that shows a color coded time line for each processor. The color coding shows the processor status. Messages between processors are indicated by lines connecting the processors involved in the communications. Controls for these message edges let the user show all messages, no messages, or only message between specified sets of processors. Summary (profiling) displays are also produced. These are of two types. One allocates information by processor, e.g., the time the processor was blocked sending, and the other allocates information by function, e.g., the time a function was blocked sending.
The objective of this work was to use direct numerical simulation (DNS) techniques to study the physics of noise generation by a high-speed turbulent jet. A Mach 0.9, Reynolds number 3,600 jet was selected because of available experimental data. New numerical methods for generating disturbances at the nozzle and computing far-field sound were developed and reported in the course of this work. Over 25 million mesh points were used in the simulations which ran for over 50,000 timesteps and required over 50,000 processor hours on state-of-the-art parallel computer systems to complete. Figures show a visualization of the jet and sound field, a comparison of the mean flow development with the experiment, a directivity comparison with the experiment, and time spectrum comparison with the experiment. Agreement is seen to be excellent. These are fully document in the attached references. Full details of the work, detailed achievements and conclusions are discussed in appendices, which are copies of publications that resulted from this work. We have studied noise mechanisms in supersonic jets, the refraction of sound by turbulence in subsonic jets, and noise sources in conjunction with a DNS of a Mach 0.9 jet.
A flight demonstration was conducted in August 1997 at the Hartsfield Atlanta (ATL) International Airport as part of low visibility landing and surface operations (LVLASO) research activities. This research was aimed at investigating technology to improve the safety and efficiency of aircraft movements on the surface during the operational phases of roll-out, turnoff, and taxi in any weather condition down to a runway visual range of 300 feet. The system tested at ATL was composed of airborne and ground-based components that were integrated to provide both the flight crew and controllers with supplemental information to enable safe, expedient surface operations. Experimental displays were installed on a Boeing 757-200 research aircraft in both headup and head-down formats. On the ground, an integrated system maintained surveillance of the airport surface and a controller interface provided routing and control instructions. While at ATL, the research aircraft performed a series of flight and taxi operations to show the validity of the operational concept at a major airport facility, to validate simulation findings, and to assess each of the individual technologies performance in an airport environment. The concept was demonstrated to over 100 visitors from the Federal Aviation Administration (FAA) and the aviation community. This paper gives an overview of the LVLASO system and ATL test activities.
Computer graphics based.