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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Mineralogy of new Antarctic achondrites with affinity to Lodran and a model of their evolution in an asteroid

We studied five new Antartic achondrites, MacAlpine Hills (MAC) 88177, Yamato (Y)74357, Y75274, Y791491 and Elephant Moraine (EET)84302 by mineralogical techniques to gain a better understanding of the mineral assemblages of a group of meteorites with an affinity to Lodran (stony-iron meteorite) and their formation processes. This group is being called lodranites. These meteorites contain major coarse-grained orthopyroxene (Opx) and olivine as in Lodran and variable amounts of FeNi metal and troilite etc. MAC88177 has more augite and less FeNi than Lodran; Y74357 has more olivine and contains minor augite; Y791491 contains in addition plagioclase. EET84302 has an Acapulco-like chondritic mineral assembladge and is enriched in FeNi metal and plagioclase, but one part is enriched in Opx and chromite. The EET84302 and MAC88177 Opx crystals have dusty cores as in Acapulco. EET84302 and Y75274 are more Mg-rich than other members of the lodranite group, and Y74357 is intermediate. Since these meteorites all have coarse-grained textures, similar major mineral assemblages, variable amounts of augite, plagioclase, FeNi metal, chromite and olivine, we suggest that they are related and are linked to a parent body with modified chondritic compositions. The variability of the abundances of these minerals are in line with a proposed model of the surface mineral assemblages of the S asteroids. The mineral assemblages can best be explained by differing degrees of loss or movements of lower temperature partial melts and recrystallization, and reduction. A portion of EET84302 rich in metal and plagioclase may represent a type of component removed from the lodranite group meteorites. Y791058 and Caddo County, which were studied for comparison, are plagioclase-rich silicate inclusions in IAB iron meteorites and may have been derived by similar process but in a different body.

Takeda, Hiroshi↗
DOE OSTI2023

Polynorbornene-based polycations

A statistical, cationic-functionalized norbornene copolymer is formed by a process including performing a vinyl addition polymerization in the presence of a metal catalyst of a first norbornene monomer substituted with a first alkyl group and at least a second norbornene monomer substituted with a second alkyl group, to form an intermediate norbornene copolymer. The second alkyl group includes a substituent which undergoes a substitution reaction with a precursor of a cationic group. The process further includes adding the precursor for the cationic group to the intermediate norbornene copolymer to form the cationic functionalized norbornene copolymer. The cationic group has a volume of 0.25 cm 3 /mol or greater (for example, a phosphonium group or an imidazolium group).

Noonan, Kevin↗
NASA NTRS1990

A proposed group management scheme for XTP multicast

The purpose of a group management scheme is to enable its associated transfer layer protocol to be responsive to user determined reliability requirements for multicasting. Group management (GM) must assist the client process in coordinating multicast group membership, allow the user to express the subset of the multicast group that a particular multicast distribution must reach in order to be successful (reliable), and provide the transfer layer protocol with the group membership information necessary to guarantee delivery to this subset. GM provides services and mechanisms that respond to the need of the client process or process level management protocols to coordinate, modify, and determine attributes of the multicast group, especially membership. XTP GM provides a link between process groups and their multicast groups by maintaining a group membership database that identifies members in a name space understood by the underlying transfer layer protocol. Other attributes of the multicast group useful to both the client process and the data transfer protocol may be stored in the database. Examples include the relative dispersion, most recent update, and default delivery parameters of a group.

Dempsey, Bert J.↗
DOE OSTI2017

Statistical Analysis of CO 2 Exposed Wells to Predict Long Term Leakage through the Development of an Integrated Neural-Genetic Algorithm

The objective of this project is to develop a computerized statistical model with the Integrated Neural-Genetic Algorithm (INGA) for predicting the probability of long-term leak of wells in CO 2 sequestration operations. This object has been accomplished by conducting research in three phases: 1) data mining of CO 2 -explosed wells, 2) INGA computer model development, and 3) evaluation of the predictive performance of the computer model with data from field tests. Data mining was conducted for 510 wells in two CO 2 sequestration projects in the Texas Gulf Coast region. They are the Hasting West field and Oyster Bayou field in the Southern Texas. Missing wellbore integrity data were estimated using an analytical and Finite Element Method (FEM) model. The INGA was first tested for performances of convergence and computing efficiency with the obtained data set of high dimension. It was concluded that the INGA can handle the gathered data set with good accuracy and reasonable computing time after a reduction of dimension with a grouping mechanism. A computerized statistical model with the INGA was then developed based on data pre-processing and grouping. Comprehensive training and testing of the model were carried out to ensure that the model is accurate and efficient enough for predicting the probability of long-term leak of wells in CO 2 sequestration operations. The Cranfield in the southern Mississippi was select as the test site. Observation wells CFU31F2 and CFU31F3 were used for pressure-testing, formation-logging, and cement-sampling. Tools run in the wells include Isolation Scanner, Slim Cement Mapping Tool (SCMT), Cased Hole Formation Dynamics Tester (CHDT), and Mechanical Sidewall Coring Tool (MSCT). Analyses of the obtained data indicate no leak of CO 2 cross the cap zone while it is evident that the well cement sheath was invaded by the CO 2 from the storage zone. This observation is consistent with the result predicted by the INGA model which indicates the well has a CO 2 leak-safe probability of 72%. This comparison implies that the developed INGA model is valid for future use in predicting well leak probability.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1985

Phenoxy resins containing pendent ethynyl groups and cured resins obtained therefrom

Phenoxy resins containing pendent ethynyl groups, the process for preparing the same, and the cured resin products obtained therefrom are disclosed. Upon the application of heat, the ethynyl groups react to provide branching and crosslinking with the cure temperature being lowered by using a catalyst if desired but not required. The cured phenoxy resins containing pendent ethynyl groups have improved solvent resistance and higher use temperature than linear uncrosslinked phenoxy resins and are applicable for use as coatings, films, adhesives, composited matrices and molding compounds.

Hergenrother, P. M.↗
DOE OSTI2015

Advanced Aqueous Separation Systems for Actinide Partitioning

One of the most challenging aspects of advanced processing of used nuclear fuel is the separation of transplutonium actinides from fission product lanthanides. This separation is essential if actinide transmutation options are to be pursued in advanced fuel cycles, as lanthanides compete with actinides for neutrons in both thermal and fast reactors, thus limiting efficiency. The separation is difficult because the chemistry of Am 3+ and Cm 3+ is nearly identical to that of the trivalent lanthanides (Ln 3+ ). The prior literature teaches that two approaches offer the greatest probability of devising a successful group separation process based on aqueous processes: 1) the application of complexing agents containing ligand donor atoms that are softer than oxygen (N, S, Cl - ) or 2) changing the oxidation state of Am to the IV, V, or VI state to increase the essential differences between Am and lanthanide chemistry (an approach utilized in the PUREX process to selectively remove Pu 4+ and UO 2 2+ from fission products). The latter approach offers the additional benefit of enabling a separation of Am from Cm, as Cm(III) is resistant to oxidation and so can easily be made to follow the lanthanides. The fundamental limitations of these approaches are that 1) the soft(er) donor atoms that interact more strongly with actinide cations than lanthanides form substantially weaker bonds than oxygen atoms, thus necessitating modification of extraction conditions for adequate phase transfer efficiency, 2) soft donor reagents have been seen to suffer slow phase transfer kinetics and hydro-/radiolytic stability limitations and 3) the upper oxidation states of Am are all moderately strong oxidants, hence of only transient stability in media representative of conventional aqueous separations systems. There are examples in the literature of both approaches having been described. However, it is not clear at present that any extant process is sufficiently robust for application at the scale necessary for commercial fuel processing supporting transmutation of transplutonium elements. This research project continued basic themes investigated by this research group during the past decade. In the Fuel Cycle Research and Development program at DOE, the current favorite process for accomplishing the separation of trivalent actinides from fission product lanthanides is the TALSPEAK process. TALSPEAK is a solvent extraction method (developed at Oak Ridge National Lab in the 1960s) based on the combination of a cation exchanging extractant (e.g., HDEHP), an actinide-selective aminopolycarboxylate complexing agent (e.g., DTPA), and a carboxylic acid buffer to control pH in the range of 3-4. Considerable effort has been expended in this research group during the past 8 years to elaborate the details of TALSPEAK in the interest of developing improved approaches to the operation of TALSPEAK-like systems. In this project we focused on defining aggregation phenomena in conventional TALSPEAK separations, on supporting the development of Advanced TALSPEAK processes, on profiling the aqueous complexation kinetics of lanthanides in TALSPEAK relevant aqueous media, on the design of new diglycolamide and N-donor extractants, and on characterizing cation-cation complexes of pentavalent actinides.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1992

Evaluation and recommendations for work group integration within the Materials and Processes Lab

The goal of this study was to evaluate and make recommendations for improving the level of integration of several work groups within the Materials and Processes Lab at the Marshall Space Flight Center. This evaluation has uncovered a variety of projects that could improve the efficiency and operation of the work groups as well as the overall integration of the system. In addition, this study provides the foundation for specification of a computer integrated manufacturing test bed environment in the Materials and Processes Lab.

Farrington, Phillip A.↗
NASA NTRS2005

Crew collaboration in space: a naturalistic decision-making perspective

Successful long-duration space missions will depend on the ability of crewmembers to respond promptly and effectively to unanticipated problems that arise under highly stressful conditions. Naturalistic decision making (NDM) exploits the knowledge and experience of decision makers in meaningful work domains, especially complex sociotechnical systems, including aviation and space. Decision making in these ambiguous, dynamic, high-risk environments is a complex task that involves defining the nature of the problem and crafting a response to achieve one's goals. Goal conflicts, time pressures, and uncertain outcomes may further complicate the process. This paper reviews theory and research pertaining to the NDM model and traces some of the implications for space crews and other groups that perform meaningful work in extreme environments. It concludes with specific recommendations for preparing exploration crews to use NDM effectively.

Review, Tutorial↗
DOE OSTI2023

Coordination and divergence in community assembly processes across co-occurring microbial groups separated by cell size

Setting the pace of life and constraining the role of members in food webs, body size can affect the structure and dynamics of communities across multiple scales of biological organization (e.g., from the individual to the ecosystem). However, its effects on shaping microbial communities, as well as underlying assembly processes, remain poorly known. Here, we analyzed microbial diversity in the largest urban lake in China and disentangled the ecological processes governing microbial eukaryotes and prokaryotes using 16S and 18S amplicon sequencing. We found that pico/nano-eukaryotes (0.22–20 μm) and micro-eukaryotes (20–200 μm) showed significant differences in terms of both community composition and assembly processes even though they were characterized by similar phylotype diversity. We also found scale dependencies whereby micro-eukaryotes were strongly governed by environmental selection at the local scale and dispersal limitation at the regional scale. Interestingly, it was the micro-eukaryotes, rather than the pico/nano-eukaryotes, that shared similar distribution and community assembly patterns with the prokaryotes. This indicated that assembly processes of eukaryotes may be coupled or decoupled from prokaryotes’ assembly processes based on eukaryote cell size. While the results support the important influence of cell size, there may be other factors leading to different levels of assembly process coupling across size classes. Additional studies are needed to quantitatively parse the influence of cell size versus other factors as drivers of coordinated and divergent community assembly processes across microbial groups. Regardless of the governing mechanisms, our results show that there are clear patterns in how assembly processes are coupled across sub-communities defined by cell size. These size-structured patterns could be used to help predict shifts in microbial food webs in response to future disturbance.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Method and system for preparing polycrystalline group III metal nitride

A process of preparing polycrystalline group III nitride chunks comprising the steps of (a) placing a group III metal inside a source chamber; (b) flowing a halogen-containing gas over the group III metal to form a group III metal halide; (c) contacting the group III metal halide with a nitrogen-containing gas in a deposition chamber containing a foil, the foil comprising at least one of Mo, W, Ta, Pd, Pt, Ir, or Re; (d) forming a polycrystalline group III nitride layer on the foil within the deposition chamber; (e) removing the polycrystalline group III nitride layer from the foil; and (f) comminuting the polycrystalline group III nitride layer to form the polycrystalline group III nitride chunks, wherein the removing and the comminuting are performed in any order or simultaneously.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Method and system for preparing polycrystalline group III metal nitride

A process of preparing polycrystalline group III nitride chunks comprising the steps of (a) placing a group III metal inside a source chamber; (b) flowing a halogen-containing gas over the group III metal to form a group III metal halide; (c) contacting the group III metal halide with a nitrogen-containing gas in a deposition chamber containing a foil, the foil comprising at least one of Mo, W, Ta, Pd, Pt, Ir, or Re; (d) forming a polycrystalline group III nitride layer on the foil within the deposition chamber; (e) removing the polycrystalline group III nitride layer from the foil; and (f) comminuting the polycrystalline group III nitride layer to form the polycrystalline group III nitride chunks, wherein the removing and the comminuting are performed in any order or simultaneously.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Space Resources and Space Settlements

This publication contains the technical papers from the five task groups that took part in the 1977 Ames Summer Study on Space Settlements and Industrialization Using Nonterrestrial Materials. The study was sponsored by the following NASA Headquarters organizations: Office of Space Science, Office of Aeronautics and Space Technology, and Office of Space Transportation Systems. The NASA Ames Research Center hosted the study and provided administrative support through its Life Sciences Directorate. Expert assistance in the many aspects of the study came from NASA Headquarters, NASA centers, universities, industry, and from individual consultants. This summer study was the largest and most comprehensive investigation of space manufacturing and habitation to date; forty senior research workers and ten students participated. The six-week study was preceded by several months of planning and preparation, and was followed by extensive work on manuscript checking, review, and assembly. The study topics reflected the research areas requiring the most intensive attention as ofrnid-1977; they were: Group I: Regenerative life-support systems and controlled environment agriculture. Group II: Parametric studies of efficient habitats in space. Time and cost analysis of a space manufacturing program plan. Group III: Detection and analysis of special classes of asteroids suitable as material resources for space manufacturing; studies of retrieval missions. Group IV: Electromagnetic mass drivers for use as interorbital engines, as devices to launch lunar material into space, and as tugs for the retrieval of asteroidal material. Group V: Chemical processing of non terrestrial material in space; manufacture of metals and glass fibers, beneficiation, and design of processing plants. These five task groups each produced two or more technical papers, signed by the contributing members. The papers were subjected to independent peer review by scientists not connected with the study. During the course of the study, frequent formal and informal exchanges of information occurred between task groups, so that the entire effort evolved in a coherent fashion and was directed toward common goals. However, each group remained responsible for the choice of its topics and for its conclusions. A listing of all the participants is given on pages vii-x. It would be inappropriate for me to single out particular people or groups for special mention, since all involved applied their skills with dedication and enthusiasm. Instead, I thank everyone for their contributions to the success of the study, and also for making it a united and warmly cooperative personal experience.

John Billingham↗
NASA NTRS2004

Over-Luminous Elliptical Galaxies

The first paper from our work has been completed and accepted for publication. Another paper presents a study of the ESO 30601 70 galaxy group, combining Chandra, XMM-Newton, and optical observations. We find that the system is a true fossil galaxy group - a group whose optical light is dominated by a single galaxy. The group X-ray emission is composed of a central, dense, cool core (10 kpc in radius) and an isothermal medium beyond the central 10 kpc. The region between 10 and 50 kpc (the cooling radius) has the same temperature as the gas from 50 to 400 kpc, although the gas cooling time between 10 and 50 kpc (2-6 Gyr) is shorter than the Hubble time. Thus, the ESO 3060170 group does not have a group-sized cooling core. We suggest that the group cooling core may have been heated by a central active galactic nucleus (AGN) outburst in the past and that the small, dense, cool core is the truncated relic of a previous cooling core. The Chandra observations also reveal a variety of X-ray features in the central region, including a finger, an edge-like feature, and a small tail, all aligned along a north-south axis, as are the galaxy light and group galaxy distribution. The proposed AGN outburst may cause gas to slosh around the center and produce these asymmetric features. The observed flat temperature profile to 1/3rvir is not consistent with the predicted temperature profile in recent numerical simulations. We compare the entropy profile of the ESO 3060170 group with those of three other groups and find a flatter relation than that predicted by simulations involving only shock heating, S approximately r approximately 0.85. This is direct evidence of the importance of non-gravitational processes in group centers. We derive the mass profiles within 1/3rvir and find that the ESO 3060170 group is the most massive fossil group known.

Forman, William↗
DOE OSTI2020

Mixed core processor unit

A method and apparatus for processing data. The data is sent to a processor unit comprising a group of neural cores, a group of digital processing cores, and a routing network connecting the group of digital processing cores. The data is processed in the processor unit to generate a result.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Metal distributions out to 0.5 r {sub 180} in the intracluster medium of four galaxy groups observed with Suzaku

We studied the distributions of metal abundances and metal-mass-to-light ratios in the intracluster medium (ICM) of four galaxy groups, MKW 4, HCG 62, the NGC 1550 group, and the NGC 5044 group, out to ∼0.5 r {sub 180} observed with Suzaku. The iron abundance decreases with radius and is about 0.2-0.4 solar beyond 0.1 r {sub 180}. At a given radius in units of r {sub 180}, the iron abundance in the ICM of the four galaxy groups was consistent with or smaller than those of clusters of galaxies. The Mg/Fe and Si/Fe ratios in the ICM are nearly constant at the solar ratio out to 0.5 r {sub 180}. We also studied systematic uncertainties in the derived metal abundances, comparing the results from two versions of atomic data for astrophysicists (ATOMDB) and single- and two-temperature model fits. Since the metals have been synthesized in galaxies, we collected K-band luminosities of galaxies from the Two Micron All Sky Survey catalog and calculated the integrated iron-mass-to-light-ratios (IMLR), or the ratios of the iron mass in the ICM to light from stars in galaxies. The groups with smaller gas-mass-to-light ratios have smaller IMLR values and the IMLR is inversely correlated with the entropy excess. Based on these abundance features, we discussed the past history of metal enrichment processes in groups of galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1980

Science Requirements Working Group (SRWG) in float zone materials processing in space: A review

A summary and history of the Float Zone Working Group was presented. The functions of this working group are to: provide an informal forum of scientific investigators for the exchange of information and ideas in the approach of the solution of common problems in float zone processing, help plan the research and development necessary to place the float zone process on a firm base of scientific understanding and advanced technological development, establish the science requirements for the AFZES for Spacelab, and seek ways to maximize the advantages of the space environment in the pursuit of these goals.

Fowle, A. A.↗