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At least 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Collection of cosmic dust in earth orbit for exobiological analysis

Two proposed NASA exobiology flight experiments are described in terms of the approaches to cosmic dust collection and the issues addressed by the analysis of the samples. A passive collector is planned for use with the Cosmic Dust Collection Facility, and an active system is described for attachment to the Space Station Freedom payload. Exobiological study of cosmic dust could provide insights on organic chemistry in the grains and on the relative abundances of biogenic elements in interstellar, cometary, and meteoric samples.

Fogleman, Guy↗
NASA NTRS1993

An automated data collection system for a Charpy impact tester

A method for automated data collection has been developed for a Charpy impact tester. A potentiometer is connected to the pivot point of the hammer and measures the angular displacement of the hammer. This data is collected with a computer and, through appropriate software, accurately records the energy absorbed by the specimen. The device can be easily calibrated with minimal effort.

Weigman, Bernard J.↗
NASA NTRS1992

Neurodynamical model of collective brain

A dynamical system which mimics collective purposeful activities of a set of units of intelligence is introduced and discussed. A global control of the unit activities is replaced by the probabilistic correlations between them. These correlations are learned during a long term period of performing collective tasks, and are stored in the synaptic interconnections. The model is represented by a system of ordinary differential equations with terminal attractors and repellers, and does not contain any man-made digital devices.

Zak, Michail↗
NASA NTRS1993

Eliminating LH2 in LOX-collect space launchers - Key to on-demand capability

Two air-breathing reusable two-stage space launch vehicle concepts are proposed, in which the first stage employs turboramjet propulsion and the second stage uses rockets, which are expected to provide very rapid response launch of 10,000 lb polar-orbit payloads. In both concepts, liquid oxygen (LOX) for the second stage is collected during first stage ascent, thus eliminating the need for LOX ground servicing facilities. In the first concept, liquid hydrogen in the amount just sufficient to condense and collect second state LOX is the only cryogenic fluid that is loaded on the vehicle at takeoff. The second concept uses the heat sink of conventional jet propulsion fuel and water coolant to drive a lightweight adaptation of the commercial LOX production process, eliminating all cryogenics at takeoff. Both concepts should permit true launch-on-demand capability with aircraftlike ground operations.

Leingang, J. L.↗
NASA NTRS1991

Collecting address traces from parallel computers

Trace driven simulation is a well-established method of performance analysis for single processor computer systems. However, efficient and accurate memory address tracing for parallel computer systems is not well understood. In this paper we present a critical survey of recently implemented approaches to address tracing and highlight the issues specific to collection of traces for both shared and distributed memory parallel computers. These issues include potential distortion of the relative ordering of events by the address tracing activity, realistic interleaving of addresses generated by multiple processors, and I/O and storage problems associated with collecting traces for large parallel systems. The strengths and weaknesses of the parallel tracing approaches are described.

Stunkel, Craig B.↗
NASA NTRS1993

A prototype urine collection device for female aircrew

Women are gaining increased access to small military cockpits. This shift has stimulated the search for practical urine containment and disposal methods for female aircrew. There are no external urine collection devices (UCD) for women that are comfortable, convenient, and leak free. We describe a prototype UCD that begins to meet this need. Materials used to make custom aviator masks were adapted to mold a perineal mask. First, a perineal cast (negative) was used to make a mold (positive). Next, a perineal mask made of wax was formed to fit the positive mold. Finally, a soft, pliable perineal mask was fabricated using the wax model as a guide. The prototype was tested for comfort, fit, and leakage. In the sitting position, less than 5 cc of urine leakage occurred with each 600 cc of urine collected. Comfort was mostly satisfactory, but ambulation was limited and the outlet design could lead to kinking and obstruction. We concluded that a perineal mask may serve as a comfortable and functional external UCD acceptable for use by females in confined environments. Changes are needed to improve comfort, fit, and urine drainage. Integration into cockpits, pressure suits, chemical defense gear, and environments where access to relief facilities is restricted is planned.

Bisson, Roger U.↗
NASA NTRS1993

Advanced solid-state array spectroradiometer data collection during HAPEX-2 Sahel

Data collection using the Advanced Solid-state Array Spectroradiometer (ASAS) during the Hydrologic Atmospheric Pilot Experiment in the Sahel (HAPEX-II Sahel) field campaign in the Republic of Niger, West Central Africa from 22 Aug. to 19 Sep. 1992 is documented. Details on the ASAS system such as the hardware, data collection methods, information on system calibration, and data processing procedures are included. The ASAS configuration deployed for HAPEX-II Sahel contains several new components, including a new sensor array and pointing system. Because of this, new calibration procedures are being developed at the same time that the first ASAS images from HAPEX-II Sahel are being processed. These new calibration procedures will be documented in a future publication.

Walthall, Charles L.↗
NASA NTRS1993

Data collection with the ACTS propagation terminal

Viewgraphs on data collection with the ACTS propagation terminal are included. Topics covered include: DACS system overview; DACS board; APT data collection computer; APT software downloading; data storage for APT; and ACTS propagation experiment data flow.

Remaklus, Will↗
NASA NTRS1994

Method and apparatus for the collection, storage, and real time analysis of blood and other bodily fluids

The present invention provides a simple, portable, relatively inexpensive apparatus for accurately and efficiently collecting, separating, testing, and even storing between about 1-20 ml, preferably about 1-10 ml, of blood or other bodily fluid in situ. The apparatus includes a collection chamber bounded on its sides by an opening in a sheet of material, preferably clear plastic, abutting a filter card. The filter card is made of fibrous material, preferably less than about a millimeter thick, having an average pore size of less than about 3 microns. Preferably, the fibers are glass and the fibrous material has an average pore size of about 1 micron. The fibrous material is treated with a carbohydrate/protein mixture which contains between about 1-40 percent wt/vol carbohydrate and about 0.1-15 percent wt/vol nonspecific protein, preferably between about 10-20 percent carbohydrate and about 5-8 percent protein. A preferred carbohydrate/protein mixture comprises about 10 percent mannitol and about 6 percent albumin. The blood or other fluid moves through the filter card by capillary action aided by an absorbent matrix with a high Klemm factor which abuts the filter card. The absorbent matrix and/or filter card can be treated with a wide spectrum of test reagents. The speed, cleanliness, and efficiency of the separation process can be altered by: (a) changing the absolute concentration of the carbohydrate/protein mixture; (b) applying positive or negative pressure to one side of the filter; and/or (c) varying the relative density and pore size of the filter card and absorbent matrix.

Whitson, Peggy A.↗
NASA NTRS1994

Collection development at the NOAA Central Library

The National Oceanic and Atmospheric Administration (NOAA) Central Library collection, approximately one million volumes, incorporates the holdings of its predecessor agencies. Within the library, the collections are filed separately, based on their source and/or classification schemes. The NOAA Central Library provides a variety of services to users, ranging from quick reference and interlibrary loan to in-depth research and online data bases.

Quillen, Steve R.↗
NASA NTRS1995

Collection Efficiency and Ice Accretion Calculations for a Sphere, a Swept MS(1)-317 Wing, a Swept NACA-0012 Wing Tip, an Axisymmetric Inlet, and a Boeing 737-300

Collection efficiency and ice accretion calculations have been made for a sphere, a swept MS(1)-317 wing, a swept NACA-0012 wing tip, an axisymmetric inlet, and a Boeing 737-300 inlet using the NPARC flow solver and the NASA Lewis LEWICE3D grid based ice accretion code. Euler flow solutions for the geometries were generated using the NPARC flow solver. The LEWICE3D grid based ice accretion program was used to calculate the impingement efficiencies and ice shapes. Ice shapes specifying rime and mixed icing conditions were generated for a 30 minute hold condition. All calculations were performed on an SGI Model Power Challenge Computer. The results have been compared to experimental flow and impingement data. In general, the calculated flow and collection efficiencies compared well with experiment, and the ice shapes looked reasonable and appeared representative of the rime and mixed icing conditions for which they were calculated.

Bidwell, Colin S.↗
NASA NTRS1995

Ropes: Support for collective opertions among distributed threads

Lightweight threads are becoming increasingly useful in supporting parallelism and asynchronous control structures in applications and language implementations. Recently, systems have been designed and implemented to support interprocessor communication between lightweight threads so that threads can be exploited in a distributed memory system. Their use, in this setting, has been largely restricted to supporting latency hiding techniques and functional parallelism within a single application. However, to execute data parallel codes independent of other threads in the system, collective operations and relative indexing among threads are required. This paper describes the design of ropes: a scoping mechanism for collective operations and relative indexing among threads. We present the design of ropes in the context of the Chant system, and provide performance results evaluating our initial design decisions.

Haines, Matthew↗
NASA NTRS1994

The Global Oscillation Network Group site survey. 1: Data collection and analysis methods

The Global Oscillation Network Group (GONG) Project is planning to place a set of instruments around the world to observe solar oscillations as continuously as possible for at least three years. The Project has now chosen the sites that will comprise the network. This paper describes the methods of data collection and analysis that were used to make this decision. Solar irradiance data were collected with a one-minute cadence at fifteen sites around the world and analyzed to produce statistics of cloud cover, atmospheric extinction, and transparency power spectra at the individual sites. Nearly 200 reasonable six-site networks were assembled from the individual stations, and a set of statistical measures of the performance of the networks was analyzed using a principal component analysis. An accompanying paper presents the results of the survey.

Hill, Frank↗
NASA NTRS1995

Plasma turbulence enhanced current collection: Results from the plasma motor generator electrodynamic tether flight

The plasma motor generator (PMG) experiment, launched June 26, 1993, was a tethered system of two identical plasma contactors connected via a 500-m conducting tether. The experiment was designed to demonstrate the ability of plasma contactors to provide a low-impedance connection between a spacecraft and the ionosphere for both the electron emission and collection. The flight data indicate that plasma contactors enhance electron collection and emission by both neutralizing the electron space charge and scattering electrons across the geomagnetic field lines. Up to a 0.3 A steady current flowed along the tether in a curcuit completed through the ionosphere. An analytical model for plasma contactor interaction with a background plasma which incorporates electron scattering by plasma waves is compared with the flight data. Good agreement between the model and the data is achieved for an effective scattering frequency equal to one twentieth of the local plasma contactor plasma frequency.

Katz, I.↗
NASA NTRS1993

The thermal history of interplanetary dust particles collected in the Earth's stratosphere

Fragments of 24 individual interplanetary dust particles (IDPs) collected in the Earth's stratosphere were obtained from NASA's Johnson Space Center collection and subjected to pulse-heating sequences to extract He and Ne and to learn about the thermal history of the particles. A motivation for the investigation was to see if the procedure would help distinguish between IDPs of asteroidal and cometary origin. The use of a sequence of short-duration heat pulses to perform the extractions is an improvement over the employment of a step-heating sequence, as was used in a previous investigation. The particles studied were fragments of larger parent IDPs, other fragments of which, in coordinated experiments, are undergoing studies of elemental and mineralogical composition in other laboratories. While the present investigation will provide useful temperature history data for the particles, the relatively large size of the parent IDPs (approximately 40 micrometers in diameter) resulted in high entry deceleration temperatures. This limited the usefulness of the study for distinguishing between particles of asteroidal and cometary origin.

Nier, A. O.↗
NASA NTRS1994

The Meteoritical Bulletin, no. 76, 1994 January: The U.S. Antarctic Meteoritie Collection

The Meteoritical Bulletin number 76 contains a list of all classified meteorites collected by the United States' Antarctic meteroite program as of the summer of 1993. The compilation includes available information on classification, mass, weathering, olivine and pyroxene composition, Al-26 activities, natural thermoluminescence levels, pairing, collection location and references to published descriptions for 5537 meteorite specimens. A list of the properties of metallic meteorites and a list of the most significant meteorites by class are also included.

Grossman, Jeffrey N.↗
NASA NTRS1995

Plume Particle Collection and Sizing from Static Firing of Solid Rocket Motors

Thermal radiation from the plume of any solid rocket motor, containing aluminum as one of the propellant ingredients, is mainly from the microscopic, hot aluminum oxide particles in the plume. The plume radiation to the base components of the flight vehicle is primarily determined by the plume flowfield properties, the size distribution of the plume particles, and their optical properties. The optimum design of a vehicle base thermal protection system is dependent on the ability to accurately predict this intense thermal radiation using validated theoretical models. This article describes a successful effort to collect reasonably clean plume particle samples from the static firing of the flight simulation motor (FSM-4) on March 10, 1994 at the T-24 test bed at the Thiokol space operations facility as well as three 18.3% scaled MNASA motors tested at NASA/MSFC. Prior attempts to collect plume particles from the full-scale motor firings have been unsuccessful due to the extremely hostile thermal and acoustic environment in the vicinity of the motor nozzle.

Sambamurthi, Jay K.↗