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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Models for compact pulsing X-ray sources.

Development of a model of a neutron star (Cen X-3) which releases the infall energy of accreted matter. Some general remarks are made on the possibility of accretion as a source of energy. It is shown that overflow of the Roche lobe is neither necessary as a source of mass nor probable in view of the observed stellar line widths of the two identified X-ray companions. While not excluding the possibility that tidal forces may drive some mass outflow, a number of models are investigated in which the material to be accreted appears in the form of a stellar wind. The behavior of the accreted gas near the accreting object is discussed, as well as the transfer of angular momentum near the accreting object. It is concluded that a relatively simple stellar wind driven accretion model appears to satisfactorily account, in a quantitative but not precise way, for most of the observed features of Cen X-3.

Ostriker, J. P.↗
NASA NTRS2011

Compact, Controlled Resistance Exercise Device

Spaceflight leads to muscle and bone atrophy. Isoinertial (free-weight) exercises provide a sufficient stimulus to elicit increases in both muscle strength and bone mineral density in Earth-based studies. While exercise equipment is in use on the International Space Station for crewmember health maintenance, current devices are too large to place in a transport vehicle or small spacecraft. Therefore, a portable computer controlled resistance exercise device is being developed that is able to simulate the inertial loading experienced when lifting a mass on Earth. This portable device weighs less than 50 lb and can simulate the resistance of lifting and lowering up to 600 lb of free-weights. The objective is to allow crewmembers to perform resistance exercise with loads capable of maintaining muscle and bone health. The device is reconfigurable and allows for the performance of typical Earth-based free-weight exercises. Forces exerted, volume of work, range of motion, time-under-tension, and speed/ acceleration of movement are recorded and can be remotely monitored to track progress and modify individual protocols based on exercise session data. A performance evaluation will be completed and data will be presented that include ground-reaction force comparisons between the device and free-weight dead-lifts over a spectrum of resistance levels. Movement biomechanics will also be presented.

Paulus, David C.↗
NASA NTRS1977

A low-cost system for reception and processing of line-scan data from LANDSAT and other sources

A low-cost transportable earth resources ground station was built in Canada and installed to operational status at Shoe Cove, Newfoundland. The system concepts developed for this station provide timely availability of data in both photographic and digital form. The system was designed with several objectives in mind: (1) to provide a system which could receive, store and process line-scan image data from a wide variety of satellites, most especially the LANDSAT and NOAA (VHRR) series, as well as aircraft scanner data, and data from future remote sensing and meteorological satellites; (2) the system has been designed to be operated by a small staff and to produce black and white images and computer-compatible tapes (CCT's) of all relevant data; (3) the system is compact in its physical design so that it is possible to configure it as a self-contained ground station, housed in a 3 x 12 meter trailer; (4) the system is designed to process all data at real-time rates or better and is designed in a modular fashion so that it can be easily upgraded to do further processing of the data, and/or to handle new satellites and sensors.

Sloan, D. S.↗
NASA NTRS2005

Development of mid-IR lasers for Laser Remote Sensing

There is an existing need in JPL and in NASA for development of mid-IR lasers, such as Quantum Cascade (QC) lasers, for in-situ and remote laser spectrometers. Mid-IR, compact, low power consumption laser spectrometers have a great potential for detection and measurements of planetary gases and biological important biomarker molecules such as H20, H202, CH4, and many additional chemical species on Mars and other Solar system planets. Another potential application of QC lasers for future NASA mission is in high power remote Laser Reflectance Spectrometers (LRS). In LSR instrument, mid-infrared lasers will act as the illumination source for conducting active mid-IR reflectance spectroscopy of solid-surfaced objects in the outer Solar System. These spectrometers have the potential to provide an incredible amount of information about the compositions of surfaces in the outer Solar System. In this work, we will discuss our current effort at JPL to advance QC lasers to a level that the laser performance, operational requirements and reliability be compatible with the instruments demands for space exploration applications.

Mid - IR lasers↗
NASA NTRS1994

The BL LAC phenomenon: X-ray observations of transition objects and determination of the x-ray spectrum of a complete sample of flat-spectrum radio sources

This report summarizes the activities related to two ROSAT investigations: (1) x-ray properties of radio galaxies thought to contain BL Lac type nuclei; and (2) x-ray spectra of a complete sample of flat-spectrum radio sources. The following papers describing the research are provided as attachments: Multiple X-ray Emission Components in Low Power Radio Galaxies; New X-ray Results on Radio Galaxies; Analysis Techniques for a Multiwavelength Study of Radio Galaxies; Separation of X-ray Emission Components in Radio Galaxies; X-ray Emission in Powerful Radio Galaxies and Quasars; Extended and Compact X-ray Emission in Powerful Radio Galaxies; and X-ray Spectra of a Complete Sample of Extragalactic Core-dominated Radio Sources.

Worrall, Diana M.↗
NASA NTRS1994

Near-infrared imaging of FSC 10214+4724 with the W. M. Keck Telescope

Near-infrared observations of the z = 2.286 IRAS source FSC 10214+4724, made with the near-infrared camera on the W. M. Keck Telescope, are reported. Deep broad-band images at 2.15 and 1.27 micrometers, and narrow-band images at 2.165 and 2.125 micrometers with 0.6 sec to 0.9 sec seeing show that FSC 10214+4724 consists of at least three distinct components in a compact group of galaxies. The source of the infrared luminosity appears to be in a strongly interacting galaxy that has a luminosity of approximately 100 times that of a present-day L* galaxy. The interaction suggests and 'age' of this galaxy of approximately equal to 10(exp 9) yr. The H-alpha emission is resolved as a source of diameter approximately equal to 5 kpc, suggesting that a starburst contributes to the observed H-alpha emission. There is an excess of objects in the FSC 10214+4724 field that could represent galaxies in an associated cluster.

Matthews, K.↗
NASA NTRS1998

Computational Nanoelectronics and Nanotechnology at NASA ARC

Both physical and economic considerations indicate that the scaling era of CMOS will run out of steam around the year 2010. However, physical laws also indicate that it is possible to compute at a rate of a billion times present speeds with the expenditure of only one Watt of electrical power. NASA has long-term needs where ultra-small semiconductor devices are needed for critical applications: high performance, low power, compact computers for intelligent autonomous vehicles and Petaflop computing technology are some key examples. To advance the design, development, and production of future generation micro- and nano-devices, IT Modeling and Simulation Group has been started at NASA Ames with a goal to develop an integrated simulation environment that addresses problems related to nanoelectronics and molecular nanotechnology. Overview of nanoelectronics and nanotechnology research activities being carried out at Ames Research Center will be presented. We will also present the vision and the research objectives of the IT Modeling and Simulation Group including the applications of nanoelectronic based devices relevant to NASA missions.

Saini, Subhash↗
NASA NTRS1998

Computational Nanoelectronics and Nanotechnology at NASA ARC

Both physical and economic considerations indicate that the scaling era of CMOS will run out of steam around the year 2010. However, physical laws also indicate that it is possible to compute at a rate of a billion times present speeds with the expenditure of only one Watt of electrical power. NASA has long-term needs where ultra-small semiconductor devices are needed for critical applications: high performance, low power, compact computers for intelligent autonomous vehicles and Petaflop computing technolpgy are some key examples. To advance the design, development, and production of future generation micro- and nano-devices, IT Modeling and Simulation Group has been started at NASA Ames with a goal to develop an integrated simulation environment that addresses problems related to nanoelectronics and molecular nanotecnology. Overview of nanoelectronics and nanotechnology research activities being carried out at Ames Research Center will be presented. We will also present the vision and the research objectives of the IT Modeling and Simulation Group including the applications of nanoelectronic based devices relevant to NASA missions.

Saini, Subhash↗
NASA NTRS2012

ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays

The objective of this work was to develop a new class of readout integrated circuit (ROIC) arrays to be operated with Geiger avalanche photodiode (GPD) arrays, by integrating multiple functions at the pixel level (smart-pixel or active pixel technology) in 250-nm CMOS (complementary metal oxide semiconductor) processes. In order to pack a maximum of functions within a minimum pixel size, the ROIC array is a full, custom application-specific integrated circuit (ASIC) design using a mixed-signal CMOS process with compact primitive layout cells. The ROIC array was processed to allow assembly in bump-bonding technology with photon-counting infrared detector arrays into 3-D imaging cameras (LADAR). The ROIC architecture was designed to work with either common- anode Si GPD arrays or common-cathode InGaAs GPD arrays. The current ROIC pixel design is hardwired prior to processing one of the two GPD array configurations, and it has the provision to allow soft reconfiguration to either array (to be implemented into the next ROIC array generation). The ROIC pixel architecture implements the Geiger avalanche quenching, bias, reset, and time to digital conversion (TDC) functions in full-digital design, and uses time domain over-sampling (vernier) to allow high temporal resolution at low clock rates, increased data yield, and improved utilization of the laser beam.

Vasile, Stefan↗
NASA NTRS2003

Rollable Thin Shell Composite-Material Paraboloidal Mirrors

An experiment and calculation have demonstrated the feasibility of a technique of compact storage of paraboloidal mirrors made of thin composite-material (multiple layers of carbon fiber mats in a polymeric matrix) shells coated with metal for reflectivity. Such mirrors are under consideration as simple, lightweight alternatives to the heavier, more complex mirrors now used in space telescopes. They could also be used on Earth in applications in which gravitational sag of the thin shells can be tolerated. The present technique is essentially the same as that used to store large maps, posters, tapestries, and similar objects: One simply rolls up the mirror to a radius small enough to enable the insertion of the mirror in a protective cylindrical case. Provided that the stress associated with rolling the mirror is not so large as to introduce an appreciable amount of hysteresis, the mirror can be expected to spring back to its original shape, with sufficient precision to perform its intended optical function, when unrolled from storage.

Meinel, Aden↗
NASA NTRS1989

Applications of algebraic image operators to model-based vision

A highly structured and compact algebraic representation of grey-level images is expanded. Addition and multiplication are defined for the set of all grey-level images, which can then be described as polynomials of two variables. Utilizing this new algebraic structure, an innovative, efficient edge-detection scheme is devised. A robust method for linear feature extraction is developed by combining the techniques of a Hough transform and a line follower with this new edge detection scheme. The major advantage of this feature extractor is its general, object-independent nature. Target attributes, such as line segment lengths, intersections, angles of intersection, and endpoints are derived by the feature extraction algorithm and employed during model matching. The feature extractor and model matcher are being incorporated into a distributed robot-control system.

Lerner, Bao-Ting↗
NASA NTRS1981

VLBI and X-ray observations of compact nuclei in pairs of galaxies

Five pairs of isolated pairs of galaxies with radio sources from the sample of Stocke et al. (1978) were observed with a three-element VLBI array operating at 4996 MHz. Parsec-scale components were detected in NGC 3894, Arp 102, and NGC 6500. Arp 102B was found to be a strong X-ray source with a luminosity in the 0.5-4.5 keV band of about 10 to the 43rd ergs/sec. Arp 102B was also found to be an elliptical galaxy for which no emission lines have been reported, and was the only source in the sample which appeared unresolved on the milli-arcsec scale, indicating that it may be related to BL Lac type objects.

Biermann, P.↗
NASA NTRS1995

Detection of compact ultraviolet nuclear emission in liner galaxies

Low-ionization nuclear emission-line regions (LINERs), which exist in a large fraction of galaxies, may be the least luminous manifestation of quasar activity. As such, they may make possible the study of the active galactic nucleus (AGN) phenomenon in the nearest galaxies. The nature of LINERs has, however, remained controversial because an AGN-like nonstellar continuum source has not been directly observed in them. We report the detection of bright (greater than or approximately = 2 x 10(exp -16) ergs/s/sq cm/A), unresolved (full width at half maximum (FWHM) less than or approximately = 0.1 sec) point sources of UV (approximately 2300 A) emission in the nuclei of nine nearby galaxies. The galaxies were imaged using the Faint Object Camera (FOC) on the Hubble Space Telescope (HST), and seven of them are from a complete sample of 110 nearby galaxies that was observed with HST. Ground-based optical spectroscopy reveals that five of the nuclei are LINERs, three are starburst nuclei, and one is a Seyfert nucleus. The observed UV flux in each of the five LINERs implies an ionizing flux that is sufficient to account to the observed emission lines through photoionization. The detection of a strong UV continuum in the LINERs argues against shock excitation as the source of the observed emission lines, and supports the idea that photoionization excites the lines in at least some objects of this class. We have analyzed ground-based spectra for most of the northern-hemisphere galaxies in the HST sample and find that 26 of them are LINERs, among which only the above five LINERs have a detected nuclear UV source.

Maoz, Dan↗
NASA NTRS1998

New Mission Concept Study: Energetic X-Ray Imaging Survey Telescope (EXIST)

This Report summarizes the activity carried out under the New Mission Concept (NMC) study for a mission to conduct a sensitive all-sky imaging survey in the hard x-ray (HX) band (approximately 10-600 keV). The Energetic X-ray Imaging Survey Telescope (EXIST) mission was originally proposed for this NMC study and was then subsequently proposed for a MIDEX mission as part of this study effort. Development of the EXIST (and related) concepts continues for a future flight proposal. The hard x-ray band (approximately 10-600 keV) is nearly the final band of the astronomical spectrum still without a sensitive imaging all-sky survey. This is despite the enormous potential of this band to address a wide range of fundamental and timely objectives - from the origin and physical mechanisms of cosmological gamma-ray bursts (GRBs) to the processes on strongly magnetic neutron stars that produce soft gamma-repeaters and bursting pulsars; from the study of active galactic nuclei (AGN) and quasars to the origin and evolution of the hard x-ray diffuse background; from the nature and number of black holes and neutron stars and the accretion processes onto them to the extreme non-thermal flares of normal stars; and from searches for expected diffuse (but relatively compact) nuclear line (Ti-44) emission in uncatalogued supernova remnants to diffuse non-thermal inverse Compton emission from galaxy clusters. A high sensitivity all-sky survey mission in the hard x-ray band, with imaging to both address source confusion and time-variable background radiations, is very much needed.

Source record↗
NASA NTRS2008

The Development of NDE Techniques for Large Cryogenic Storage Tanks

Objectives of this project are: (1) Develop and demonstrate NDE techniques to evaluate the condition of large cryogenic Dewars (typically 50,000 to 900,000 gaL). (2) These tanks are used across NASA for launch pads, engine test stands, cryogenic wind tunnels and other facilities: they represent a major investment. (3) Issues addressed: (1) Insulation integrity of existing Dewars (powdered insulation under vacuum or sometimes ambient pressure (LO2), (2) Post fabrication insulation verification without full chill-down to avoid thermal cycling the tank (fatigue limitation of piping and compaction of Perlite).

Youngquist, Robert↗
NASA NTRS2018

What is EA?

An enterprise architecture (EA) is a conceptual blueprint that defines the structure and operation of an organization. The intent of an enterprise architecture is to determine how an organization can most effectively achieve its current and future objectives. A single slide PowerPoint, size 36" x 48" has been produced for printing onto a poster board for display in the Pathways Internship showcase November 2018. This poster board presentation is a display of my internship from 2014 to present, to include my NIFS (NASA Interns, Fellowships, Scholarships) internship, ITSS (Information Technology Support Services) contract, and current Pathways internship. The presentation discusses my years producing deliverables for: the ISS (International Space Station) Anomaly Project in 2014, the FJET (Frangible Joint Empirical Test) database project in 2015, the CUI (Compact Unique Identifier) project in early 2016, and various Enterprise Architecture deliverables and contributions such as the Roadmap SQL (Structured Query Language) stored procedure and architectural views of Program data elements.

MySQL↗
NASA NTRS2000

Interferometry for X-Ray Astronomy

With direct imaging, the nature of distant astronomical objects and the physical mechanisms that control them can be constrained and understood. From Galileo's observations of the solar system, to Hubble Space Telescope's imaging of distant galaxies, improved astronomical imaging has always brought scientific understanding. The x-ray band of the spectrum, where exotic objects can have extremely high surface brightness, is ideally suited for high resolution imaging, but has lacked ultra-high quality telescopes. We report a practical x-ray interferometer that features high efficiency, affordable mirrors, adjustable baseline, and can be scaled to a full size observatory. Our prototype system, with just under one millimeter of baseline, created fringes at 1.25 keV with angular resolution of 100 milli-arcseconds. With a larger version of this interferometer in orbit it will be possible to resolve stars, black holes and other compact constituents of the universe. We can study the environments of pulsars, image and then model relativistic blast waves, study the space-time metric near the surface of a black hole, watch the physical formation of astrophysical jets, and study the dynamos of stellar coronae.

Cash, Webster↗
NASA NTRS2017

The Cloud Feedback Model Intercomparison Project (CFMIP) contribution to CMIP6.

The primary objective of CFMIP is to inform future assessments of cloud feedbacks through improved understanding of cloud-climate feedback mechanisms and better evaluation of cloud processes and cloud feedbacks in climate models. However, the CFMIP approach is also increasingly being used to understand other aspects of climate change, and so a second objective has now been introduced, to improve understanding of circulation, regional-scale precipitation, and non-linear changes. CFMIP is supporting ongoing model inter-comparison activities by coordinating a hierarchy of targeted experiments for CMIP6, along with a set of cloud-related output diagnostics. CFMIP contributes primarily to addressing the CMIP6 questions 'How does the Earth system respond to forcing?' and 'What are the origins and consequences of systematic model biases?' and supports the activities of the WCRP Grand Challenge on Clouds, Circulation and Climate Sensitivity. A compact set of Tier 1 experiments is proposed for CMIP6 to address this question: (1) what are the physical mechanisms underlying the range of cloud feedbacks and cloud adjustments predicted by climate models, and which models have the most credible cloud feedbacks? Additional Tier 2 experiments are proposed to address the following questions. (2) Are cloud feedbacks consistent for climate cooling and warming, and if not, why? (3) How do cloud-radiative effects impact the structure, the strength and the variability of the general atmospheric circulation in present and future climates? (4) How do responses in the climate system due to changes in solar forcing differ from changes due to CO2, and is the response sensitive to the sign of the forcing? (5) To what extent is regional climate change per CO2 doubling state-dependent (non-linear), and why? (6) Are climate feedbacks during the 20th century different to those acting on long-term climate change and climate sensitivity? (7) How do regional climate responses (e.g. in precipitation) and their uncertainties in coupled models arise from the combination of different aspects of CO2 forcing and sea surface warming? CFMIP also proposes a number of additional model outputs in the CMIP DECK, CMIP6 Historical and CMIP6 CFMIP experiments, including COSP simulator outputs and process diagnostics to address the following questions. 1. How well do clouds and other relevant variables simulated by models agree with observations? 2. What physical processes and mechanisms are important for a credible simulation of clouds, cloud feedbacks and cloud adjustments in climate models? 3. Which models have the most credible representations of processes relevant to the simulation of clouds? 4. How do clouds and their changes interact with other elements of the climate system?

carbon dioxide↗