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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Observation of super high energy big family with large scale Fe emulsion chambers

In order to get higher efficiencies for detecting hadrons and to make technical improvements in the chamber structure, the Mt. Kambala Emulsion Chamber Collaboration constructed 57 sq. m. of Fe chamber, with thickness 29 c.u.(1c.u.=17.6 mm Fe), using 300 tons of Fe plates and made the first exposure from Sept., 1982 to May, 1984. The photosensitive layers consist of X-ray films of Sakura N type, Fuji No. 100 type and Tianjin III type, some of them contain also emulsion plates of Fuji ET7B type. They are inserted between the Fe plates at 2 c.u., beginning at 5 c.u. from the chamber top. In a number of blocks, 3 mm spacings are provided at every 2 c.u. of Fe plates to facilitate the replacement of photosensitive layers, without disassembling the chamber. On the bottom of the chamber Fe plates of thickness 9 mm are placed in order to shield the chamber from the radioactivities of the ground. An event, numbered K2 58 of visible energy sigma E sub gamma = 7345 TeV was found in this exposure. No obvious halo is seen in the event and all the showers are clearly separated and easy to measure. A brief report of the preliminary results is presented.

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NASA NTRS1985

Comparison of big event with calculations of the air shower development

The incidence of high energy hadrons and electron-photons in air showers at various stages of development is calculated. Numerical calculation is used to solve the diffusion equation for a nuclear cascade and analytical calculation for cascade shower induced gamma rays. From these calculations, one can get the longitudinal development of the high energy hadron and electron-photon components, and the energy spectra of these components at various depths of air shower development. The total number of hadrons (N sub H) and electron-photon components (N sub gamma) are related according to stages of the air shower development and primary energy. The relation of the total energy of hadron and electron-photon component above the threshold energy is given. The energy balance between both components is also a useful parameter to study high energy events accompanying air showers. The relation of N sub H and fractional hadronic energy E (sum E sub H sup gamma/sum E sub H sup gamma + Sum E sub gamma) is calculated. This relation is helpful to understand the stage of air shower development(t) and primary energy (E sub p).

Niwa, M.↗
NASA NTRS1985

Bigness is in the eye of the beholder

This report reviews an investigation of judgments of size and distance as required of pilots in flight. The experiments covered a broad spectrum of basic psychophysiological issues involving the measurement of visual accommodation and its correlation with various other dependent variables. Psychophysiological issues investigated included the size-distance invariance hypothesis, the projection of afterimages, the moon illusion, night and empty-field myopia, the dark focus and its so-called Mandelbaum effect, the nature and locus of the accommodative stimulus, the relation between accommodation, retinal size, and perceived size, and possible relationships among accommodative responses, autonomic balance, and personality variables.

Roscoe, S. N.↗
NASA NTRS1987

Big whorls carry little whorls

The aim of the research was to explore the space-time structure of homogeneous turbulence by computing and then interpreting the two-point spectra and correlations of the velocity and pressure fields. Many of these statistics are of considerable practical importance. In particular, it is of interest to compare the different time and length integral scales and microscales for Eulerian and Lagrangian qualities, and to compare the space and time spectra.

Hunt, J. C. R.↗
NASA NTRS1987

Multispectral remote sensing as stratigraphic and structural tool, Wind River Basin and Big Horn Basin areas, Wyoming

The use of Landsat TM, Airborne Imaging Spectrometer, and airborne Thermal IR Multispectral Scanner data in the geological evaluation of two sites in central Wyoming is described and illustrated with diagrams, maps, photographs, sample images, and tables of numerical data. The value of the remotely sensed information on the areal variation of attitude, sequence, thickness, and lithology of exposed strata is demonstrated; details of the data analysis are given; and the specialized software packages employed are briefly characterized.

Lang, Harold R.↗
NASA NTRS1988

Coordinated videomagnetograph observations by the Big Bear and Huairou Observatories

A videomagnetograph patterned after the BBSO system was installed at Huairou in 1987, and five days of coordinated observing were carried out from September 24 to 29, 1987. The data were combined to make a continuous movie of the fields abound a stable spot. A 57 hour magnetograph run with two seven hour gaps were achieved from 2330 UT, September 24 to 0830 UT, September 27. The frames were reregistered and justified to eliminate the change of scale with meridian distance. The intensities were corrected for cosine effect. Preliminary examination of the data shows continuous decrease of the total magnetic field during this period by more than 50 percent. The principal loss of flux appears to be due to cancellation at the main neutral line. Some flux disappears due to fragmentation, which makes the elements fall below the threshold, while only a tiny loss due to diffusion can be detected. It is planned to continue this program during Max 1991, including transverse field measurements as well. Several long runs were already obtained in 1988.

Wang, Haimin↗
NASA NTRS1987

Herbicide treatment effects on properties of mountain big sagebrush soils after fourteen years

The effects of sagebrush conversion on the soil properties of a high-elevation portion of the Western Intermountain Sagebrush Steppe (West, 1983) are described. Changes were found in only a few soil chemical properties after conversion to grassland. It was found that surface concentrations of N were lower under grass vegetation than under undisturbed vegetation. Undershrub net N mineralization rates were higher under shrubs in the sagebrush vegetation than under former shrubs in the grass vegetation.

Burke, I. C.↗
NASA NTRS1989

Big savings from small holes

The status and results to date of the NASA-Lewis/USAF Astronautics study of technology for large spacecraft heat-dissipation by means of liquid-droplet radiation (LDR) are discussed. The LDR concept uses a droplet generator to create billions of 200-micron droplets of a heatsink fluid which will cool through radiation into deep space as they fly toward a dropet collector. This exposure to the space environment entails the maintenance of vapor pressure as low as 10 to the -7th torr; the fluid must also be very stable chemically. While certain oils are good fluids for LDR use at low temperatures, higher-temperature heatsink fluids include Li, Sn, and Ga liquid metals.

White, Alan↗
NASA NTRS1989

Asteroids - The big picture

An attempt is made to construct a simple model of the evolution of the asteroid belt from the data available about the individual asteroids. Data on the meaning of taxonomic types, the stratigraphy of the asteroid belt, the compositional meaning of Tholen space, collisional and dynamical history, and asteroid shapes are reviewed. Two main paradoxes concerning asteroids, called the ordinary chondrite mystery and the olivine problems, are briefly described. Finally, the tentative model is presented, showing how it takes into account condensation locations, heating, collisional evolution, and delivery of asteroids to earth.

Bell, Jeffrey F.↗
NASA NTRS1985

Instellar Gas Experiment (IGE): Testing interstellar gas particles to provide information on the processes of nucleosynthesis in the big bang stars and supernova

The Interstellar Gas Experiment (IGE) is designed to collect particles of the interstellar gas - a wind of interstellar media particles moving in the vicinity of the solar system. These particles will be returned to earth where the isotopic ratios of the noble gases among these particles will be measured. IGE was designed and programmed to expose 7 sets of six copper-beryllium metallic collecting foils to the flux of neutral interstellar gas particles which penetrate the heliosphere to the vicinity of the earth's orbit. These particles are trapped in the collecting foils and will be returned to earth for mass-spectrographic analysis when Long Duration Exposure Facility (LDEF) on which IGE was launched, is recovered.

Lind, Don↗
NASA NTRS1991

Testing the Big Bang: Light elements, neutrinos, dark matter and large-scale structure

Several experimental and observational tests of the standard cosmological model are examined. In particular, a detailed discussion is presented regarding: (1) nucleosynthesis, the light element abundances, and neutrino counting; (2) the dark matter problems; and (3) the formation of galaxies and large-scale structure. Comments are made on the possible implications of the recent solar neutrino experimental results for cosmology. An appendix briefly discusses the 17 keV thing and the cosmological and astrophysical constraints on it.

Schramm, David N.↗
NASA NTRS1993

The mission events graphic generator software: A small tool with big results

Utilization of graphics has long been a useful methodology for many aspects of spacecraft operations. A personal computer based software tool that implements straight-forward graphics and greatly enhances spacecraft operations is presented. This unique software tool is the Mission Events Graphic Generator (MEGG) software which is used in support of the Hubble Space Telescope (HST) Project. MEGG reads the HST mission schedule and generates a graphical timeline.

Lupisella, Mark↗
NASA NTRS1994

Small scale sequence automation pays big dividends

Galileo sequence design and integration are supported by a suite of formal software tools. Sequence review, however, is largely a manual process with reviewers scanning hundreds of pages of cryptic computer printouts to verify sequence correctness. Beginning in 1990, a series of small, PC based sequence review tools evolved. Each tool performs a specific task but all have a common 'look and feel'. The narrow focus of each tool means simpler operation, and easier creation, testing, and maintenance. Benefits from these tools are (1) decreased review time by factors of 5 to 20 or more with a concomitant reduction in staffing, (2) increased review accuracy, and (3) excellent returns on time invested.

Nelson, Bill↗
NASA NTRS1995

Image and compositional characteristics of the LDEF Big Guy impact crater

A 5.2 mm crater in Al-metal represents the largest found on LDEF. We have examined this crater by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and time-of-flight/secondary ion mass spectroscopy (TOF-SIMS) in order to determine if there is any evidence of impactor residue. Droplet and dome-shaped columns, along with flow features, are evidence of melting. EDS from the crater cavity and rim show Mg, C, O and variable amounts of Si, in addition to Al. No evidence for a chondritic impactor was found, and it hypothesized that the crater may be the result of impact with space debris.

Bunch, T. E.↗
NASA NTRS1994

1919+479: Big WAT in a poor cluster

New x-ray, optical, and redshift data are presented for the cluster of galaxies associated with the giant, 1 Mpc diameter, wide-angle tailed (WAT) radio galaxy 1919+479. The ROSAT Position-Sensitive Proportional Counter (PSPC) pointed observation shows an x-ray peak on the WAT and elongated diffuse emission tracing the galaxy distribution. In addition, an asymmetric extension of emission exists between the tails of the WAT. The fitting of a Raymond-Smith thermal model to the x-ray spectra suggests an approximately = 2 keV temperature intracluster medium (ICM). The cooling time and irregular morphology rule out a cluster-wide cooling flow. The x-ray luminosity and temperature are consistent with the velocity dispersion, 480 km/s, estimated from 31 galaxy velocities. However, this velocity distribution is significantly non-Gaussian, which along with the x-ray morphology, suggests incomplete virialization in the cluster. Substructure analysis does not reveal significant clumping in the velocities/positions; but, the spatial distribution of galaxies is very elongated. Also, the cD galaxy producing the WAT does not have a significant radial peculiar velocity with respect to the cluster centroid. These characteristics are consistent with a merger scenario in which a subcluster has crossed the cluster core in the plane of the sky and has dispersed. We compare this cluster with the post-merger cluster Abell 2634 (Pinkney et al., 1993), containing the prototype WAT, and with a recent N-Body/Hydro simulation of merging clusters. The similarities indicate that the cluster 1919+479 may be the poor extreme of a class of clusters in which the bulk motion in the ICM, caused by a subcluster merger, in shaping the central WAT.

Pinkney, Jason↗
NASA NTRS1997

Comet Shoemaker-Levy 9 Fragment Size Estimates: How Big was the Parent Body?

The impact of Comet Shoemaker-Levy 9 on Jupiter in July, 1994 was the largest, most energetic impact event on a planet ever witnessed. Because it broke up during a close encounter with Jupiter in 1992, it was bright enough to be discovered more than a year prior to impact, allowing the scientific community an unprecedented opportunity to assess the effects such an event would have. Many excellent observations were made from Earth-based telescopes, the Hubble Space Telescope (HST), and the Galileo spacecraft en route to Jupiter. In this paper, these observations are used in conjunction with computational simulations performed with the CTH shock-physics hydrocode to determine the sizes of the fifteen fragments that made discernible impact features on the planet. To do this, CTH was equipped with a radiative ablation model and a postprocessing radiative ray-trace capability that enabled light-flux predictions (often called the impact flash) for the viewing geometries of Galileo and ground-based observers. The five events recorded by Galileo were calibrated to give fragment size estimates. Compared against ground-based and HST observations, these estimates were extended using a least-squares analysis to assess the impacts of the remaining ten fragments. Some of the largest impacts (L, G, and K) were greater that 1 km in diameter, but the density of the fragments was low, about 0.25 g/cm(exp 3). The volume of the combined fifteen fragments would make a sphere 1.8 km in diameter. Assuming a prebreakup density of 0.5 g/cm(exp 3), the parent body of Shoemaker-Levy 9 had a probable diameter of 1.4 km. The total kinetic energy of all the impacts was equivalent to the explosive yield of 300 Gigatons of TNT.

Crawford, David A.↗
NASA NTRS1998

From Engineering Science to Big Science: The NACA and NASA Collier Trophy Research Project Winners

The chapters of this book discuss a series of case studies of notable technological projects carried out at least in part by the NACA and NASA. The case studies chosen are those projects that won the National Aeronautic Association's (NAA) Collier Trophy for "the greatest achievement in aviation in America, the value of which has been thoroughly demonstrated by use during the preceding year." Looking back on the whole series of projects we can examine both what successes were seen as important at various times, and how the goals and organization of these notable projects changed over time.

Mack, Pamela E.↗
NASA NTRS2001

New Tool Creates a Big Stir

A new self-adjusting, retractable pin tool for friction stir welding is now used in the manufacturing of components for NASA Space Shuttles. Friction stir welding is a process that makes straight-line welds without bringing the parent material to a liquid state. This is accomplished through high-speed rotation, which generates frictional heat between the welding tool and the piece being welded. This heat causes the material to soften to the point of plasticity without allowing it to melt. The plasticized material is then transferred from the front edge of the welding tool to the trail edge, where it joins the pieces being welded. However, a major flaw of this method is its reliance on a single-piece pin tool. The weld is left unfinished and a hole remains where the pin was inserted. The hole must be covered with a rivet in order to preserve the integrity of the weld. The NASA-developed pin tool, however, eliminates the need for this finishing step, as its retraction allows continuous rewelding at lesser depths, until the hole is completely closed. With this NASA technology, welding of higher strength alloys, as well as non-planer and variable thickness structures can be achieved.

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