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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Supplier's Status for Critical Solid Propellants, Explosive, and Pyrotechnic Ingredients

In the early 1970's a program was initiated at the Naval Surface Warfare Center/Indian Head Division (NSWC/IHDIV) to address the well-known problems associated with availability and suppliers of critical ingredients. These critical ingredients are necessary for preparation of solid propellants and explosives manufactured by the Navy. The objective of the program was to identify primary and secondary (or back-up) vendor information for these critical ingredients, and to develop suitable alternative materials if an ingredient is unavailable. In 1992 NSWC/IHDIV funded Chemical Propulsion Information Agency (CPIA) under a Technical Area Task (TAT) to expedite the task of creating a database listing critical ingredients used to manufacture Navy propellant and explosives based on known formulation quantities. Under this task CPIA provided employees that were 100 percent dedicated to the task of obtaining critical ingredient suppliers information, selecting the software and designing the interface between the computer program and the database users. TAT objectives included creating the Explosive Ingredients Source Database (EISD) for Propellant, Explosive and Pyrotechnic (PEP) critical elements. The goal was to create a readily accessible database, to provide users a quick-view summary of critical ingredient supplier's information and create a centralized archive that CPIA would update and distribute. EISD funding ended in 1996. At that time, the database entries included 53 formulations and 108 critical used to manufacture Navy propellant and explosives. CPIA turned the database tasking back over to NSWC/IHDIV to maintain and distribute at their discretion. Due to significant interest in propellant/explosives critical ingredients suppliers' status, the Propellant Development and Characterization Subcommittee (PDCS) approached the JANNAF Executive committee (EC) for authorization to continue the critical ingredient database work. In 1999, JANNAF EC approved the PDCS panel task. This paper is designed to emphasize the necessity of maintaining a JANNAF community supported database, which monitors PEP critical ingredient suppliers' status. The final product of this task is a user friendly, searchable database that provides a quick-view summary of critical ingredient supplier's information. This database must be designed to serve the needs of JANNAF and the propellant and energetic commercial manufacturing community as well. This paper provides a summary of the type of information to archive each critical ingredient.

Sims, B. L.↗
NASA NTRS1982

Explosive Separation of Electrical Connectors

Concept proposed for separating electrical cable that connects the Space Shuttle to deployable payloads could be used to sever electrical connections in other inaccessible environments. Although triggered explosively, connector would not release combustion products that could damage sensitive electronics. Suggested applications are undersea exploration, chemical processing and areas with high levels of radiation.

Barbour, R. T.↗
NASA NTRS1983

The extraordinary extragalactic supernova remnant in NGC 4449. II - X-ray and optical investigations

Einstein Observatory X-ray observations indicate that the SNR in NGC 4449 is the most luminous X-ray, as well as optical and radio, SNR known. New optical spectroscopy, together with the X-ray data, suggest this exceptional luminosity to be due to chemically enriched material at unusually high densities. A model is proposed in which this SNR resulted from the explosion of a massive star in a medium of nearly 25/cu cm density about 100 years ago. The chemistry in question further suggests that the SNR in NGC 4449 resulted from the explosion of a star whose mass was greater than 25 solar masses.

Blair, W. P.↗
NASA NTRS1992

High-temperature mass spectrometric degassing of enstatite chondrites - Implications for pyroclastic volcanism on the aubrite parent body

The volatile contents of a number of enstatite chondrite falls of different chemical groups (EH; EL) and petrologic types (EH3-5; EL6) were investigated in order to find evidence of explosive pyroclastic volcanism, supporting the mechanism proposed by Wilson and Keil (1991) to explain the lack of aubritic basalts in aubrites. It is shown that abundant volatiles are likely to have been released upon partial melting of enstatite chondritelike precursor materials of aubrites, enough to drive pyroclastic volcanic eruptions which would explain the lack of aubritic basalts.

Muenow, David W.↗
NASA NTRS1995

Computational Study of Flow Establishment in Hypersonic Pulse Facilities

This paper presents a study of the temporal evolution of the combustion flowfield established by the interaction of ram-accelerator-type projectiles with an explosive gas mixture accelerated to hypersonic speeds in an expansion tube. The Navier-Stokes equations for a chemically reacting gas are solved in a fully coupled manner using an implicit, time accurate algorithm. The solution procedure is based on a spatially second order, total variation diminishing (TVD) scheme and a temporally second order, variable-step, backward differentiation formula method. The hydrogen-oxygen chemistry is modeled with a 9-species, 19-step mechanism. The accuracy of the solution method is first demonstrated by several benchmark calculations. Numerical simulations of expansion tube flowfields are then presented for two different configurations. In particular, the development of the shock-induced combustion process is followed. In one case, designed to ensure ignition only in the boundary layer, the lateral extent of the combustion front during the initial transient phase was surprisingly large. The time histories of the calculated thrust and drag forces on the ram accelerator projectile are also presented.

Yungster, S.↗
NASA NTRS1998

Contributions of Nimbus 7 TOMS Data to Volcanic Study and Hazard Mitigation

Nimbus TOMS data have led to advancements among many volcano-related scientific disciplines, from the initial ability to quantify SO2 clouds leading to derivations of eruptive S budgets and fluxes, to tracking of individual clouds, assessing global volcanism and atmospheric impacts. Some of the major aspects of TOMS-related research, listed below, will be reviewed and updated: (1) Measurement of volcanic SO2 clouds: Nimbus TOMS observed over 100 individual SO2 clouds during its mission lifetime; large explosive eruptions are now routinely and reliably measured by satellite. (2) Eruption processes: quantification of SO2 emissions have allowed assessments of eruption sulfur budgets, the evaluation of "excess" sulfur, and inferences of H2S emissions. (3) Detection of ash: TOMS data are now used to detect volcanic particulates in the atmosphere, providing complementary analyses to infrared methods of detection. Paired TOMS and AVHRR studies have provided invaluable information on volcanic cloud compositions and processes. (4) Cloud tracking and hazard mitigation: volcanic clouds can be considered gigantic tracers in the atmosphere, and studies of the fates of these clouds have led to new knowledge of their physical and chemical dispersion in the atmosphere for predictive models. (5) Global trends: the long term data set has provided researchers an unparalleled record of explosive volcanism, and forms a key component in assessing annual to decadal trends in global S emissions. (6) Atmospheric impacts: TOMS data have been linked to independent records of atmospheric change, in order to compare cause and effect processes following a massive injection of SO2 into the atmosphere. (7) Future TOMS instruments and applications: Nimbus TOMS has given way to new satellite platforms, with several wavelength and resolution modifications. New efforts to launch a geostationary TOMS could provide unprecedented observations of volcanic activity.

Krueger, Arlin J.↗
NASA NTRS1988

Emergency-Evacuation Cart

Proposed cart designed to remove injured worker from vicinity of hazardous chemical spill. Self-propelled cart enables rescuer to move victim of industrial accident quickly away from toxic, flammable, explosive, corrosive, carcinogenic, asphyxiating, or extremely cold liquids. Intended for use where too dangerous for ambulances and other vehicles to approach accident site. Constructed of high-strength tubing, rides on bicycle wheels with balloon tires. Rescuer steers cart with handle at rear. Estimated mass of fully equipped vehicle is 650 lb.

Fedor, Otto H.↗
NASA NTRS1992

On determining the primordial helium abundance from the spectra of H II galaxies

A data set of 53 H II galaxies and giant H II regions whose observed abundances have reliable formal uncertainties reveals that the O/H-He/H relation used to determine the primordial helium abundance (PBA) has a highly significant physical dispersion. Consideration of possible sources of scatter indicates that it is almost certainly one-sided, i.e., upward from a minimum value of He/H at each O/H. The presence of an asymmetric dispersion casts doubt on values of PBA obtained by extrapolating ridge-line fits to the O/H-He/H relation. The loss of oxygen in SN explosions will lead naturally to a positive dispersion in He/H. The observed dispersions in He/H can be explained by chemical evolution models in which 0-95 percent of the newly synthesized oxygen is lost. It is concluded that in H II galaxies and giant H II regions PBA can be reliably determined only by fitting to the lower envelope of the O/H-He/H relation.

Campbell, Alison↗
NASA NTRS1987

Large negative Ti-50 anomalies in refractory inclusions from the Murchison carbonaceous chondrite - Evidence for incomplete mixing of neutron-rich supernova ejecta into the solar system

An ion microprobe was used to measure Ti-50 variations in hibonite-rich inclusions from the Murchison chondrite. Both deficits and excesses of the isotope were found, depending on the inclusion being scanned. The anomalies were not correlated with the mineralogy, chemical composition, other isotopic anomalies of Ti, etc. The lack of correlations indicates that the cosmic chemical memory model (Clayton, 1981) cannot explain the observed variations. The Ti-50 concentrations may have originated when a supernova explosion triggered the collapse of a molecular cloud that formed the solar system. The solar system Ti-50 anomalies were from the cloud, not the progenitor star.

Hinton, Richard W.↗
NASA NTRS1992

A detailed petrological analysis of hydrated, low-nickel, nonchondritic stratospheric dust particles

A detailed petrological analysis of three low-Ni, K-bearing, nonchondritic stratospheric dust particles is performed, and these particles are compared to products of high-energy, explosive (Plinian-type) volcanic events. The analytical electron microscope (AEM) analyses show pervasive layer silicates, carbonate and goethite, and chemical fractionation in the matrix of these particles similar to hydrothermal alteration in volcanic ejecta. Along with low Ni content and the presence of potassium, the texture and mineralogy of particles L2001-18, L2001-20, and L2002 C2 are similar to at least two nonchondritic stratospheric dust particles of the igneous subgroup for which an extraterrestrial origin has been suggested based on their minor- and trace-element abundances. The petrological characteristics of some low-Ni, K-bearing nonchondritic stratospheric dust particles supports a probable terrestrial volcanic origin, but the AEM data alone cannot exclude an extraterrestrial origin for these particles.

Rietmeijer, Frans J. M.↗
NASA NTRS1981

Development of a polysilicon process based on chemical vapor deposition, phase 1

The development of a dichlorosilane-based reductive chemical vapor deposition process for the production of polycrystalline silicon is discussed. Experimental data indicate that the ease of ignition and explosion severity of dichlorosilane (DCS)/air mixtures is substantially attenuated if the DCS is diluted with hydrogen. Redesign of the process development unit to accommodate safety related information is described. Several different sources of trichlorosilane were used to generate a mixture of redistributed chlorosilanes via Dowex ion exchange resin. The unseparated mixtures were then fed to an experimental reactor in which silicon was deposited and the deposited silicon analyzed for electrically active impurities. At least one trichlorosilane source provided material of requisite purity. Silicon grown in the experimental reactor was converted to single crystal material and solar cells fabricated and tested.

Mccormick, J.↗
NASA NTRS1984

Al-26 in the interstellar medium

The amount of dispersed interstellar Al-26 detected by the HEAO 3 gamma-ray spectrometer cannot have been synthesized by supernova explosions if current calculations of the production ratio p(26)/p(27) approximately equal to 0.001 are correct. Simple models of chemical evolution of the Galaxy are presented to explain this point. The observed Al-26 is more likely due to about 100 million dispersed novae, or to a single old (10,000-1,000,000 yr) supernova remnant that today surrounds the solar system. If the Al-26 is dispersed, the high interstellar ratio today Al-26/Al-27 about equal to 0.00002 calls into question the requirement that a supernova trigger for formation of the solar system was the cause of a concentration 3-times larger. Also discussed is p-process production in novae with application to the question of live Sm-146 in the solar system.

Clayton, D. D.↗
NASA NTRS1975

Materials selection criteria and data

The properties of materials selected for use in oxygen systems are examined. Specifically, materials are selected according to trade-offs between chemical compatibility, ignition temperature, combustion characteristics, and physical properties. Quantitative energy sources and energy release rates capable of causing material combustion or explosion were also considered.

Source record↗
NASA NTRS2003

Near-Infrared Spectra of Type Ia Supernovae

We report near-infrared (NIR) spectroscopic observations of 12 'branch-normal' Type Ia supernovae (SNe Ia) that cover the wavelength region from 0.8 to 2.5 microns. Our sample more than doubles the number of SNe Ia with published NIR spectra within 3 weeks of maximum light. The epochs of observation range from 13 days before maximum light to 18 days after maximum light. A detailed model for a Type Ia supernovae is used to identify spectral features. The Doppler shifts of lines are measured to obtain the velocity and thus the radial distribution of elements. The NIR is an extremely useful tool to probe the chemical structure in the layers of SNe Ia ejecta. This wavelength region is optimal for examining certain products of the SNe Ia explosion that may be blended or obscured in other spectral regions. We identify spectral features from Mg II, Ca II, Si II, Fe II, Co II, Ni II, and possibly Mn II. We find no indications for hydrogen, helium, or carbon in the spectra. The spectral features reveal important clues about the physical characteristics of SNe Ia. We use the features to derive upper limits for the amount of unburned matter, to identify the transition regions from explosive carbon to oxygen burning and from partial to complete silicon burning, and to estimate the level of mixing during and after the explosion. Elements synthesized in the outer layers during the explosion appear to remain in distinct layers. That provides strong evidence for the presence of a detonation phase during the explosion as it occurs in delayed detonation or merger models. Mg II velocities are found to exceed 11,000 - 15,000 km/s, depending on the individual SNe Ia. That result suggests that burning during the explosion reaches the outermost layers of the progenitor and limits the amount of unburned material to less than 10% of the mass of the progenitor. Small residuals of unburned material are predicted by delayed detonation models but are inconsistent with pure deflagration or merger models. Differences in the spectra of the individual SNe Ia demonstrate the variety of these events.

Marion, G. H.↗
NASA NTRS2008

Portable Device Analyzes Rocks and Minerals

inXitu Inc., of Mountain View, California, entered into a Phase II SBIR contract with Ames Research Center to develop technologies for the next generation of scientific instruments for materials analysis. The work resulted in a sample handling system that could find a wide range of applications in research and industrial laboratories as a means to load powdered samples for analysis or process control. Potential industries include chemical, cement, inks, pharmaceutical, ceramics, and forensics. Additional applications include characterizing materials that cannot be ground to a fine size, such as explosives and research pharmaceuticals.

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NASA NTRS2012

Volatile Transport by Volcanic Plumes on Earth, Venus and Mars

Explosive volcanic eruptions can produce sustained, buoyant columns of ash and gas in the atmosphere (Fig. 1). Large flood basalt eruptions may also include significant explosive phases that generate eruption columns. Such eruptions can transport volcanic volatiles to great heights in the atmosphere. Volcanic eruption columns can also redistribute chemical species within the atmosphere by entraining ambient atmosphere at low altitudes and releasing those species at much higher altitudes.

Glaze, Lori S.↗
NASA NTRS1993

Classical novae - Contributions to the interstellar medium

Theoretical results predicting yields of various isotopes in nova outbursts are reviewed. Emphasis is placed on the stardust and gas-phase chemical anomalies that may be contributed to the Galactic ISM by classic novae. It is concluded that most of the heavy isotope anomalies are produced by about 25 percent of novae that occur in systems containing massive O-Ne-Mg white dwarfs. The dust-production scenario for novae is summarized, and it is argued that explosions on O-Ne-Mg white dwarfs may lead to the formation of dust grains that carry the Ne-E and Mg-26 anomalies. Quantitative constraints are placed on the degree to which classical novae participate in the production of chemical anomalies, both in the primitive solar system and on a Galactic scale.

Gehrz, Robert D.↗