Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “imaging and visualization”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Concentration Measurements in a Cold Flow Model Annular Combustor Using Laser Induced Fluorescence

A nonintrusive concentration measurement method is developed for determining the concentration distribution in a complex flow field. The measurement method consists of marking a liquid flow with a water soluble fluorescent dye. The dye is excited by a two dimensional sheet of laser light. The fluorescent intensity is shown to be proportional to the relative concentration level. The fluorescent field is recorded on a video cassette recorder through a video camera. The recorded images are analyzed with image processing hardware and software to obtain intensity levels. Mean and root mean square (rms) values are calculated from these intensity levels. The method is tested on a single round turbulent jet because previous concentration measurements have been made on this configuration by other investigators. The previous results were used to comparison to qualify the current method. These comparisons showed that this method provides satisfactory results. 'Me concentration measurement system was used to measure the concentrations in the complex flow field of a model gas turbine annular combustor. The model annular combustor consists of opposing primary jets and an annular jet which discharges perpendicular to the primary jets. The mixing between the different jet flows can be visualized from the calculated mean and rms profiles. Concentration field visualization images obtained from the processing provide further qualitative information about the flow field.

Morgan, Douglas C.↗
NASA NTRS2007

Development of Hairpin Vortices in Turbulent Spots and End-Wall Transition

The end-stage phase of boundary layer transition is characterized by the development of hairpin-like vortices which evolve rapidly into patches of turbulent behavior. In general, the characteristics of the evolution form this hairpin stage to the turbulent stage is poorly understood, which has prompted the present experimental examination of hairpin vortex development and growth processes. Two topics of particular relevance to the workshop focus will be covered: 1) the growth of turbulent spots through the generatio and amalgamation of hairpin-like vortices, and 2) the development of hairpin vortices during transition in an end-wall junction flow. Brief summaries of these studies are described below. Using controlled generation of hairpin vortices by surface injection in a critical laminar boundary layer, detailed flow visualization studies have been done of the phases of growth of single hairpin vortices, from the initial hairgin generation, through the systematic generation of secondary hairpin-like flow structures, culminating in the evolution to a turbulent spot. The key to the growth process is strong vortex-surface interactions, which give rise to strong eruptive events adjacent to the surface, which results in the generation of subsequent hairpin vortex structures due to inviscid-viscuous interactions between the eruptive events and the free steam fluid. The general process of vortex-surface fluid interaction, coupled with subsequent interactions and amalgamation of the generated multiple hairpin-type vortices, is demonstrated as a physical mechanism for the growth and development of turbulent spots. When a boundary layer flow along a surface encounters a bluff body obstruction extending from the surface (such as cylinder or wing), the strong adverse pressure gradients generated by these types of flows result in the concentration of the impinging vorticity into a system of discrete vortices near the end-wall juncture of the obstruction, with the extensions of the vortices engirdling the obstruction to form "necklace" or "horseshoe" vortices. Recent hydrogen bubble and particle image visualization have shown that as Reynolds number is increased for a laminar approach flow, the flow will become critical, and a destabilization of the necklace vortices results in the development of an azimuthal waviness, or "kinks", in the vortices. These vortex kinks are accentuated by Biot-Savart effects, causing portions of a distorted necklace vortex to make a rapid approach to the surface, precipitating processes of localized, three-dimensional surface interactions. These interactions result in the rapid generation, focussing, and ejection of thin tongues of surface fluid, which rapidly roll-over and appear as hairpin vortices in the junction region. Subsequent amalgamation of these hairpin vortices with the necklace vortices produces a complex transitional-type flow. A presentation of key results from both these studies will be done, emphasizing both the ubiquity of such hairpin-type flow structures in manifold transitional-type flows, and the importance of vortex-surface interactions n the development of hairpin vortices.

Smith, Charles R.↗
NASA NTRS1998

Neural learning rules for the vestibulo-ocular reflex

Mechanisms for the induction of motor learning in the vestibulo-ocular reflex (VOR) were evaluated by recording the patterns of neural activity elicited in the cerebellum by a range of stimuli that induce learning. Patterns of climbing-fiber, vestibular, and Purkinje cell simple-spike signals were examined during sinusoidal head movement paired with visual image movement at stimulus frequencies from 0.5 to 10 Hz. A comparison of simple-spike and vestibular signals contained the information required to guide learning only at low stimulus frequencies, and a comparison of climbing-fiber and simple-spike signals contained the information required to guide learning only at high stimulus frequencies. Learning could be guided by comparison of climbing-fiber and vestibular signals at all stimulus frequencies tested, but only if climbing fiber responses were compared with the vestibular signals present 100 msec earlier. Computational analysis demonstrated that this conclusion is valid even if there is a broad range of vestibular signals at the site of plasticity. Simulations also indicated that the comparison of vestibular and climbing-fiber signals across the 100 msec delay must be implemented by a subcellular "eligibility" trace rather than by neural circuits that delay the vestibular inputs to the site of plasticity. The results suggest two alternative accounts of learning in the VOR. Either there are multiple mechanisms of learning that use different combinations of neural signals to drive plasticity, or there is a single mechanism tuned to climbing-fiber activity that follows activity in vestibular pathways by approximately 100 msec.

NASA Discipline Neuroscience↗
DOE OSTI2020

Systems-level investigation of aqueous batteries for understanding the benefit of water-in-salt electrolyte by synchrotron nanoimaging

Water-in-salt (WIS) electrolytes provide a promising path toward aqueous battery systems with enlarged operating voltage windows for better safety and environmental sustainability. In this work, a new electrode couple, LiV 3 O 8 -LiMn 2 O 4 , for aqueous Li-ion batteries is investigated to understand the mechanism by which the WIS electrolyte improves the cycling stability at an extended voltage window. Operando synchrotron transmission x-ray microscopy on the LiMn 2 O 4 cathode reveals that the WIS electrolyte suppresses the mechanical damage to the electrode network and dissolution of the electrode particles, in addition to delaying the water decomposition process. Because the viscosity of WIS is notably higher, the reaction heterogeneity of the electrodes is quantified with x-ray absorption spectroscopic imaging, visualizing the kinetic limitations of the WIS electrolyte. This work furthers the mechanistic understanding of electrode–WIS electrolyte interactions and paves the way to explore the strategy to mitigate their possible kinetic limitations in three-dimensional architectures.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Blockchain based Communication Architectures with Applications to Private Security Networks

Existing communication protocols in high consequence security networks are highly centralized. While this naively makes the controls easier to physically secure, external actors require fewer resources to disrupt the system because there are fewer points in the system can be destroyed or interrupted without the entire system failing. We present a solution to this problem using a proof-of-work-based blockchain implementation built on MultiChain. We construct a test-bed network containing two types of data input: visual imagers and microwave sensor information. These data types are ubiquitous in perimeter intrusion detection security systems and allow a realistic representation of a real-world network architecture. The cameras in this system use an object detection algorithm to nd important targets in the scene. The raw data from the camera and the outputs from the detection algorithm are then placed in a transaction on the distributed ledger. Similarly, microwave data is used to detect relevant events and are placed in a transaction. These transactions are then bundled into blocks and broadcast to the rest of the network using the Bitcoin-based MultiChain protocol. We develop five tests to examine the security metrics of our network. We performed the five security metric test using different sized networks from 7 to 39 nodes to determine how the metrics scale with respect to size. We nd that when compared to a centralized architecture our implementation provides a resiliency increase that is expected from a blockchain-based protocol without slowing the system so much that a human operator would notice. Furthermore, our approach is able to detect tampering in real time. Based on these results, we theorize that security networks in general could use a blockchain-based approach in a meaningful way.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Development and Standup Testing of a System to Observe Fission Gas Release During Transient Heating of Nuclear Fuel Element Segments

As part of an effort to increase the burnup of nuclear fuels used in Light Water Reactors, the mechanisms and timing of fission gas release during high temperature transients must be studied. In this work, a system was built to observe fission gas release of fuel element sections under evacuated conditions, at temperatures up to 800 °C. System capabilities and limitations are overviewed in this report. The system was further tested with a hydrogen-infused titanium foils and gas release was observed in agreement with literature observations. Pressure was monitored with two sensors, and temperature was monitored using a thermocouple and a pyrometer with continuous visual imaging.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1972

The Mariner Mars 1971 orbiter.

The Mariner Mars 1971 (MM '71) orbiter spacecraft, launched toward Mars in the spring of 1971, was designed to offer the first opportunity for sustained observations in the near vicinity of another planet of our solar system. The MM '71 spacecraft, like its predecessors, is fully attitude stabilized about three axes, using the sun and Canopus as references, an orientation which allows use of photovoltaic solar panels for primary power and permits two-way communication to the earth through a high-gain directional antenna. Midcourse and orbit insertion maneuvers use the sun-Canopus orientation as a reference direction for initiating commanded turns. Scientific instruments employed during Mars orbital operations are mounted on a two-degree-of-freedom platform controlled by commands from the central computer and sequencer. Science measurements to be obtained by the MM '71 spacecraft include television visual imaging, infrared radiometry, infrared spectroscopy, ultraviolet spectroscopy, S-band radio occultation, and celestial mechanics.

Scull, J. R.↗
NASA NTRS1974

Graphics shadowing analysis

Visual image is generated on cathode-ray tube screen to scale and is constructed according to dimensions of specified craft. Once displayed, image may be manipulated by several different means.

Hayes, S. R.↗
NASA NTRS1973

Mariner 9, an instrument of dynamical science

Mariner 9 viewed Mars and its satellites for a period of almost a year, transmitting doppler, time delay, visual images, and spectra to earth from its satellite orbit. This paper reviews the reduction of Mariner 9 data to more accurately define the dynamical characteristics of the Martian system. Primary results include the discovery of triaxiality of Martian gravity field and physical shape of Mars, and the verification of the discrepancy in optical and dynamic flattening. The impact of the Mariner 9 results on future space missions is evaluated in terms of the accuracy of control of a spacecraft in a 24.6 hour synchronous orbit about Mars.

Jordan, J. F.↗
NASA NTRS1975

Automatically-focusing microscope system for live tissue observation

System includes focus-sensing arrangement which controls servo to keep microscope constantly focused on target. Microscope objective is moved along optical axis. System includes two video cameras that are used as transducers for sensing focus. Incoming visual image is split by beam splitter so that one-half of information is fed to each camera.

Mansour, M. N.↗
NASA NTRS1975

The Viking Orbiter and its Mariner inheritance

The orbiter system of the Viking spacecraft performs the functions of transporting the lander into orbit around Mars, surveying the proposed landing sites, relaying lander data to earth, and conducting independent scientific observations of Mars. The orbiter system is a semiautomatic, solar-powered, triaxially stabilized platform capable of making trajectory corrections and communicating with earth on S-band. Its instruments for visual imaging, detecting water vapor, and thermal mapping are mounted on a separate two-degree-of-freedom scan platform. Radio science is conducted at three frequencies, using the main S-band system, a separate X-band derived from the S-band, and the UHF one-way link with the lander.

Wolfe, A. E.↗
NASA NTRS1976

Superconductive neuristor R-junction

Device incorporating specially-configured pure metal transition region can be developed to simulate a nerve cell. Combination of such cells may be formed to simulate an eye or brain and can be used in recognizing characters and other visual images.

Reible, S. A.↗
NASA NTRS1976

The Viking landing sites - Selection and certification

During the past several years the Viking project developed plans to use Viking orbiter instruments and earth-based radar to certify the suitability of the landing sites selected as the safest and most scientifically rewarding using Mariner 9 data. During June and July 1976, the earth-based radar and orbital spacecraft observations of some of the prime and backup sites were completed. The results of these combined observations indicated that the Viking 1 prime landing area in the Chryse region of Mars is geologically varied and possibly more hazardous than expected, and was not certifiable as a site for the Viking 1 landing. Consequently, the site certification effort had to be drastically modified and lengthened to search for a site that might be safe enough to attempt to land. The selected site considered at 47.5 deg W, 22.4 deg N represented a compromise between desirable characteristics observed with visual images and those inferred from earth-based radar. It lies in the Chryse region about 900 kilometers northwest of the original site.

Masursky, H.↗
NASA NTRS1978

A design for a 1984 Mars rover

A Mars rover is planned for the mid-1980's as a follow-up to the Viking program, and as a prelude to a return-to-earth mission of Martian samples in the late eighties or early nineties. An overall view of the rover's configuration is presented with a summary of basic design parameters. Six subsystems are outlined: computing, with a 10 to the 8th bit bubble memory; mobility, designed for a journey of 100 km in 2 earth years; science sample acquisition, including a soil auger and hard rock drill; power, supplied by an RTG and stored in batteries; telecommunication, with 50 K bit UHF transmission relayed through an orbiter; and visual imaging, employing two television cameras, each with an 800 x 800 pixel charge coupled device. Scientific research goals include information about Martian seismic characteristics, magnetic field, surface heat flow, chemical composition, geology along a transverse, and meteorology. Attention is given to the necessity of rover autonomy from earth commands.

Dobrotin, B. M.↗
NASA NTRS1979

Improving low-illumination video

Nonmoving TV pictures are improved by electronic system that removes much of the "snow" or random noise in image. System integrates and averages picture elements in real time and thereby allows easier and more accurate evaluation of image, visually and by computer.

Sapirstein, R. L.↗
NASA NTRS1978

The Ad Hoc Mars Airplane science working group

The capability of a remotely piloted airplane as a Mars exploration vehicle in the aerial survey mode is assessed. Specific experiment areas covered include: visual imaging; gamma ray and infrared reflectance spectroscopy; gravity field; magnetic field and electromagnetic sounding; and atmospheric composition and dynamics. It is concluded that (1) the most important use of a plane in the aerial survey mode would be in topical studies and returned sample site characterization; (2) the airplane offers the unique capability to do high resolution, oblique imaging, and repeated profile measurements in the atmospheric boundary layer; and (3) it offers the best platform from which to do electromagnetic sounding.

Clarke, V. C., Jr.↗