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Results for “SCALE Enhancement Activities”

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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2010

Parallel Computing in SCALE

The SCALE computational architecture has remained basically the same since its inception 30 years ago, although constituent modules and capabilities have changed significantly. This SCALE concept was intended to provide a framework whereby independent codes can be linked to provide a more comprehensive capability than possible with the individual programs - allowing flexibility to address a wide variety of applications. However, the current system was designed originally for mainframe computers with a single CPU and with significantly less memory than today's personal computers. It has been recognized that the present SCALE computation system could be restructured to take advantage of modern hardware and software capabilities, while retaining many of the modular features of the present system. Preliminary work is being done to define specifications and capabilities for a more advanced computational architecture. This paper describes the state of current SCALE development activities and plans for future development. With the release of SCALE 6.1 in 2010, a new phase of evolutionary development will be available to SCALE users within the TRITON and NEWT modules. The SCALE (Standardized Computer Analyses for Licensing Evaluation) code system developed by Oak Ridge National Laboratory (ORNL) provides a comprehensive and integrated package of codes and nuclear data for a wide range of applications in criticality safety, reactor physics, shielding, isotopic depletion and decay, and sensitivity/uncertainty (S/U) analysis. Over the last three years, since the release of version 5.1 in 2006, several important new codes have been introduced within SCALE, and significant advances applied to existing codes. Many of these new features became available with the release of SCALE 6.0 in early 2009. However, beginning with SCALE 6.1, a first generation of parallel computing is being introduced. In addition to near-term improvements, a plan for longer term SCALE enhancement activities has been developed to provide an integrated framework for future methods development. Some of the major components of the SCALE parallel computing development plan are parallelization and multithreading of computationally intensive modules and redesign of the fundamental SCALE computational architecture.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2018

Full-Scale Testing of Active Flow Control Enhanced Vertical Tail

This paper describes wind tunnel test results from a joint NASA/Boeing research effort to advance active flow control (AFC) technology to enhance aerodynamic efficiency. A full-scale Boeing 757 vertical tail model equipped with 37 sweeping jet actuators was tested at the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The model was tested at a nominal airspeed of 100 knots and across rudder deflections and sideslip angles that covered the vertical tail flight envelope. The flow separation control optimization was performed at the maximum rudder deflection of 30° and sideslip angles of 0° and -7.5°. Greater than 20% increase in side force were achieved at maximum rudder deflection and the two sideslip angles with a 31-actuator configuration. AFC caused significant increases in suction pressure on the actuator side and associated side force enhancement. The successful demonstration of this application cleared the way for a subsequent flight demonstration on the Boeing 757 ecoDemonstrator in 2015.

Whalen, Edward A.↗
NASA NTRS1994

Simulated life cycles of persistent anticyclonic anomalies over the North Pacific: Role of synoptic-scale eddies

This study examines the role of synoptic-scale eddies during the development of persistent anticyclonic height anomalies over the central North Pacific in a general circulation model under perpetual January conditions. The General Circulation Model (GCM) replicates the basic characteristics of the evolution of the anomaly patterns found in observations. The life cycle is characterized by the rapid establishment of the major anomaly center and considerably longer maintenance and decay phases, which include the development of downstream anomaly centers. The simulation also shows a realistic evolution of synoptic-scale activity beginning with enhanced activity off the east coast of Asia prior to onset, followed by a northward shift of the Pacific storm track, which lasts throughout the maintenance phase. The initial enhancement of synoptic-scale eddy activity is associated with a large-scale cyclonic anomaly that developes over Siberia several days prior to the onset of the main anticyclonic anomaly over the central North Pacific. The observations, however, show considerable interdecadel variability in the details of the composite onset behavior; it is unclear whether this variability is real or whether it reflects differences in the data assimilation systems. The role of the time mean flow and synoptic-scale eddies in the development of the persistent Pacific anomalies is studied within the context of a kinetic energy budget in which the flow is decomposed into the time-mean, low-frequency (timescales longer than 10 days), and synoptic (timescales less than 6 days) components. The budget, which is carried out for the simulation at 500 mb, shows that the initial growth of the persistent anticyclonic anomalies is associated with barotropic conversions of energy, with approximately equal contributions coming from the mean flow and the synoptic-scale eddies. After onset the barotropic conversion from the mean flow dominates, whereas the decay phase is associated with baroclinic processes within the low-frequency flow.

Higgins, R. W.↗
DOE OSTI2021

Atomic Layer Deposition with TiO2 for Enhanced Reactivity and Stability of Aromatic Hydrogenation Catalysts

Hydrogenation of aromatic molecules in fossil- and bio-derived fuels is essential for decreasing emissions of harmful combustion products and addressing growing concerns around urban air pollution. In this work, we used atomic layer deposition to significantly enhance the hydrogenation performance of a conventional supported Pd catalyst by applying an ultrathin coating of TiO2 in a scalable powder coating process. The TiO2-coated catalyst showed substantial gains in the conversion of multiple aromatic molecules, including a 5-fold improvement in turnover frequency versus the uncoated catalyst in the hydrogenation of naphthalene. This activity enhancement was maintained upon scaling the coating synthesis process from 3 to 100 g. Based on the results from Xray photoelectron spectroscopy, X-ray absorption spectroscopy, and computational modeling, the activity enhancement was attributed to ensemble effects resulting from partial TiO2 coverage of the Pd surface rather than fundamental changes to the Pd electronic structure. Additional durability testing confirmed that the TiO2 coating improved the thermal and hydrothermal stability of the catalyst as well as tolerance toward sulfur impurities in the reactant stream. Using an economic model of an industrial deep hydrogenation process, we found that an increase in catalyst activity or lifetime of 2× would justify even a relatively high estimate for the cost of TiO2 atomic layer deposition coatings at scale

atomic layer↗
NASA NTRS2022

Low-Speed Performance Enhancement using Localized Active Flow Control: Simulations, Scaling and Design of Localized Active Flow Control on the Common Research Model (4/4)

This report is dedicated to the application of localized AFC on the NASA CRM-HL wind tunnel model, with focus on the aileron application discussed in the CFD study (final report document #2). The experience developed for the Reference Aircraft guided the implementation on the CRM model. CFD evaluations are performed on a representative high-lift configuration, for a set of aileron deflections, and at relevant flow conditions. Alternative flow control actuator layouts are proposed and design consideration for practical integration into the existing CRM-HL model are set forth. The CFD simulations indicate that the aerodynamic performance improvements due to AFC obtained for the CRM-HL are consistent with those achieved for the Reference Aircraft. The observed changes in L/D are smaller than for the Reference Aircraft because the CRM has a higher leading edge sweep angle and a different relative aileron size. Conceptual design studies confirmed that the integration of an AFC equipped aileron into the existing wind tunnel model is feasible.

AFC↗
NASA NTRS2015

Performance Enhancement of a Full-Scale Vertical Tail Model Equipped with Active Flow Control

This paper describes wind tunnel test results from a joint NASA/Boeing research effort to advance active flow control (AFC) technology to enhance aerodynamic efficiency. A full-scale Boeing 757 vertical tail model equipped with sweeping jet actuators was tested at the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The model was tested at a nominal airspeed of 100 knots and across rudder deflections and sideslip angles that covered the vertical tail flight envelope. A successful demonstration of AFC-enhanced vertical tail technology was achieved. A 31- actuator configuration significantly increased side force (by greater than 20%) at a maximum rudder deflection of 30deg. The successful demonstration of this application has cleared the way for a flight demonstration on the Boeing 757 ecoDemonstrator in 2015.

Whalen, Edward A.↗
DOE OSTI2021

Characterization of Mammalian In Vivo Enhancers Using Mouse Transgenesis and CRISPR Genome Editing [Book Chapter]

Embryonic morphogenesis is strictly dependent on tight spatiotemporal control of developmental gene expression, which is typically achieved through the concerted activity of multiple enhancers driving cell type-specific expression of a target gene. Mammalian genomes are organized in topologically associated domains, providing a preferred environment and framework for interactions between transcriptional enhancers and gene promoters. While epigenomic profiling and three-dimensional chromatin conformation capture have significantly increased the accuracy of identifying enhancers, assessment of subregional enhancer activities via transgenic reporter assays in mice remains the gold standard for assigning enhancer activity in vivo. Once this activity is defined, the ideal method to explore the functional necessity of a transcriptional enhancer and its contribution to target gene dosage and morphological or physiological processes is deletion of the enhancer sequence from the mouse genome. Here we present detailed protocols for efficient introduction of enhancer-reporter transgenes and CRISPR-mediated genomic deletions into the mouse genome, including a step-by-step guide for pronuclear microinjection of fertilized mouse eggs. We provide instructions for the assembly and genomic integration of enhancer-reporter cassettes that have been used for validation of thousands of putative enhancer sequences accessible through the VISTA enhancer browser, including a recently published method for robust site-directed transgenesis at the H11 safe-harbor locus. Together, these methods enable rapid and large-scale assessment of enhancer activities and sequence variants in mice, which is essential to understand mammalian genome function and genetic diseases.

cis-regulatory elements↗
NASA NTRS1974

On the development of noise-producing large-scale wavelike eddies in a turbulent jet

The development of large-scale wavelike eddies in a two-dimensional turbulent jet was studied. The basic mean flow develops from a mixing region type with an initial specified boundary layer thickness into a fully developed jet. The role of the varicose and sinuous modes as these develop in a growing mean flow is brought out. In general, it was found, for a given frequency parameter, the varicose mode has a shorter streamwise lifetime than the sinuous mode. The latter, for lower frequency ranges, persists past the end of the potential core only to be subject to dissolution by the more enhanced fine scale turbulent activity in that region.

Merkine, L. O.↗
DOE OSTI2026

Quantitative DNA Stable Isotope Probing Identifies Active Microorganisms Assimilating Volatile Fatty Acids in Full-Scale Enhanced Biological Phosphorus Removal Processes

Enhanced biological phosphorus removal (EBPR) systems often rely on exogenous carbon sources, such as volatile fatty acids (VFAs), to achieve higher P removal. Here, we employed DNA quantitative stable isotope probing (qSIP) using two VFAs, acetate and propionate, in cyclic anaerobic/aerobic incubations to assess their effects on P cycling and microbial activity with biomass from two full-scale EBPR water resource-recovery facilities that utilize VFA addition. We found that anaerobic VFA uptake preferences differed within known groups of PAOs, such as Candidatus Accumulibacter and Tetrasphaera-affiliated members (e.g., Ca. Phosphoribacter), between the two biomasses. The combination of qSIP with metagenomics identified isotopically labeled phages that were linked to active PAOs, highlighting their potential roles in modulating EBPR community composition and activity. The highest levels of anaerobic labeling from acetate were in genomes belonging to Saccharimonadales and Rickettsiales, which are generally host-associated with bacteria and eukaryotes, respectively. Furthermore, this finding highlights the possibility of cross-feeding between PAO hosts and their parasites or predators, as well as the role of so-far uncharacterized organisms participating in carbon cycling under EBPR conditions. Collectively, these results expand our understanding of the ecological interactions involved in communities anaerobically uptaking VFAs and cycling P that are central to EBPR.

Polyphosphate accumulating organisms↗
DOE OSTI2024

Development of PWHT-Free, Reduced Activation Creep-Strength Enhanced Bainitic Ferritic Steel for Large-Scale Fusion Reactor Components

A compositional modification has been proposed to validate an alloy design which potentially eliminates the requirement of post-weld heat treatment (PWHT) while preserving the advantage of mechanical properties in a reduced activation bainitic ferritic steel based on Fe-3Cr-3W-0.2V- 0.1Ta-Mn-Si-C, in weight percent, developed at Oak Ridge National Laboratory in 2007. The alloy design includes reducing the hardness in the as-welded condition for improving toughness, while increasing the hardenability for preserving the high-temperature mechanical performance such as creep-rupture resistance in the original steel. To achieve such a design, a composition range with a reduced C content combining with an increased Mn content has been proposed and investigated. Newly proposed “modified” steel successfully achieved an improved impact toughness in the as- welded condition, while the creep-rupture performance across the weldments without PWHT demonstrated ~50% improvement of the creep strength compared to that of the original steel weldment after PWHT. The obtained results strongly support the validity of the proposed alloy design.

Yamamoto, Yukinori↗
DOE OSTI2015

Atomic Scale Analysis of the Enhanced Electro- and Photo-Catalytic Activity in High-Index Faceted Porous NiO Nanowires

Catalysts play a significant role in clean renewable hydrogen fuel generation through water splitting reaction as the surface of most semiconductors proper for water splitting has poor performance for hydrogen gas evolution. The catalytic performance strongly depends on the atomic arrangement at the surface, which necessitates the correlation of the surface structure to the catalytic activity in well-controlled catalyst surfaces. Herein, we report a novel catalytic performance of simple-synthesized porous NiO nanowires (NWs) as catalyst/co-catalyst for the hydrogen evolution reaction (HER). The correlation of catalytic activity and atomic/surface structure is investigated by detailed high resolution transmission electron microscopy (HRTEM) exhibiting a strong dependence of NiO NW photo- and electrocatalytic HER performance on the density of exposed high-index-facet (HIF) atoms, which corroborates with theoretical calculations. Significantly, the optimized porous NiO NWs offer long-term electrocatalytic stability of over one day and 45 times higher photocatalytic hydrogen production compared to commercial NiO nanoparticles. Our results open new perspectives in the search for the development of structurally stable and chemically active semiconductor-based catalysts for cost-effective and efficient hydrogen fuel production at large scale.

08 HYDROGEN↗
NASA NTRS1999

Large-Scale Coronal Heating from the Solar Magnetic Network

In Fe 12 images from SOHO/EIT, the quiet solar corona shows structure on scales ranging from sub-supergranular (i.e., bright points and coronal network) to multi- supergranular. In Falconer et al 1998 (Ap.J., 501, 386) we suppressed the large-scale background and found that the network-scale features are predominantly rooted in the magnetic network lanes at the boundaries of the supergranules. The emission of the coronal network and bright points contribute only about 5% of the entire quiet solar coronal Fe MI emission. Here we investigate the large-scale corona, the supergranular and larger-scale structure that we had previously treated as a background, and that emits 95% of the total Fe XII emission. We compare the dim and bright halves of the large- scale corona and find that the bright half is 1.5 times brighter than the dim half, has an order of magnitude greater area of bright point coverage, has three times brighter coronal network, and has about 1.5 times more magnetic flux than the dim half These results suggest that the brightness of the large-scale corona is more closely related to the large- scale total magnetic flux than to bright point activity. We conclude that in the quiet sun: (1) Magnetic flux is modulated (concentrated/diluted) on size scales larger than supergranules. (2) The large-scale enhanced magnetic flux gives an enhanced, more active, magnetic network and an increased incidence of network bright point formation. (3) The heating of the large-scale corona is dominated by more widespread, but weaker, network activity than that which heats the bright points. This work was funded by the Solar Physics Branch of NASA's office of Space Science through the SR&T Program and the SEC Guest Investigator Program.

Falconer, David A.↗
DOE OSTI2014

SCALE Enhancements for Detailed Cask Dose Rate Analysis - Paper 37

The Nuclear Fuels Storage and Transportation Planning Project and the Used Fuel Disposition Campaign, both under the US Department of Energy (DOE) Office of Nuclear Energy, require the ability to predict k{sub eff}, heat generation and temperature distributions, and external dose rates from any combination of commercial spent nuclear fuel assemblies loaded into any type of licensed cask. Work in the Reactor and Nuclear Systems Division at Oak Ridge National Laboratory has begun to develop the UNF-ST[and]DARDS system (Used Nuclear Fuel Storage, Transportation and Disposal Analysis Resource and Data System) that uses many of the nuclear analysis codes from the SCALE package, a comprehensive database of used nuclear fuel inventories from utilities, and a library of model template files to produce complete input files for the various types of UNF computational analyses. UNF-ST[and]DARDS uses the template files and input parameters that are applicable to a safety analysis to assemble and execute a complete input file, collect the output files and relevant information for subsequent calculations, and illustrate calculation results as a function of decay time and other relevant analysis parameters. This paper will focus on the shielding aspects and the ability to predict external dose rates from as-loaded casks. Realistic dose rate values based on actual canister fuel contents may be used in developing appropriate plans, procedures, and methods to keep personnel radiation exposures as low as reasonably achievable during cask repackaging and transportation operations, as well as in performing total system analyses and transportation risk evaluations. The MAVRIC shielding sequence of the SCALE package was created for the US Nuclear Regulatory Commission for analyzing dose rates outside of storage, transfer, or transportation casks loaded with spent nuclear fuel. MAVRIC contains automated variance reduction capabilities based on the CADIS and FW-CADIS methods that are effective for optimizing deep penetration Monte Carlo shielding problems for achieving low relative uncertainties in short computing times. MAVRIC uses the Denovo discrete ordinates code to compute importance maps and biased source terms for the Monaco fixed-source Monte Carlo code, which can use multi-group or continuous-energy cross section data. ORIGEN (Oak Ridge Isotope Generation and Depletion) is the SCALE computer code for calculating time-dependent isotopic concentrations during irradiation and decay for more than 2,200 nuclides that can be produced by nuclear fuel irradiation and activation. A series of SCALE enhancements was implemented to enable automatic decay heat and radiation source term generation and shielding safety analysis of as-loaded casks. The enhancements to SCALE made under this project will be a part of the SCALE 6.2 release expected in fall 2014. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1975

On the development of noise-producing large-scale wavelike eddies in a plane turbulent jet

The paper studies the development of large-scale wavelike eddies in a two-dimensional turbulent jet, extending earlier work on the mixing region (Liu, 1974). The basic mean flow developes from one of mixing-region type with an initially specified boundary-layer thickness into a fully developed jet. This study brings out the role of the varicose and sinuous modes as they develop in a growing mean flow. In general, it is found that, for a given frequency parameter, the varicose mode has a shorter streamwise lifetime than the sinuous mode. For lower frequencies, the latter persists past the end of the potential core only to become subject to dissipation by the enhanced fine-scale turbulent activity in that region.

Merkine, L.-O.↗
NASA NTRS1977

Soft X-ray observations of large-scale coronal active region brightenings

One hundred fifty-six large-scale enhancements of X-ray emission from solar active regions were studied on full-disk filterheliograms to determine characteristic morphology and expansion rates for heated coronal plasma. The X-ray photographs were compared with H-alpha observations of flares, sudden filament disappearances, sprays, and loop prominence systems (LPS). Eighty-one percent of the X-ray events were correlated with H-alpha filament activity, but only 44% were correlated with reported H-alpha flares. The X-ray enhancements took the form of loops or arcades of loops ranging in length from 60,000 km to 520,000 km and averaging 15,000 km in width. Lifetimes ranged from at least 3 hr to more than 24 hr. The event frequency was approximately 1.4 per day. X-ray loop arcades evolved from sharp-edged clouds in cavities vacated by rising H-alpha filaments. Expansion velocities of the loops were about 50 km/s immediately after excitation and 1-10 km/s several hours later. These long-lived loop arcades are identified with LPS, and it is suggested that the loops outlined magnetic fields which were reconnecting after filament eruptions. Another class of X-ray-enhanced loops stretched outside active regions and accompanied sprays or lateral filament ejections. It is suggested that these loops outlined closed magnetic fields guiding slow-mode shocks from flares and filament eruptions.

Rust, D. M.↗
DOE OSTI2022

Electrochemical device comprising thin porous metal sheet

Electrochemical device using thin micro-porous metal sheets. The porous metal sheet may have a thickness less than 200 μm, provides three-dimensional networked pore structures of pore sizes in the range of 2.0 nm to 5.0 μm, and is electrically conductive. The micro-porous metal sheet is used for positively and/or negatively-charged electrodes by providing large specific contact surface area of reactants/electron. Nano-sized catalyst or features can be added inside pores of the porous metal sheet of pore sizes at sub- and micrometer scale to enhance the reaction activity and capacity. Micro-porous ceramic materials may be coated on the porous metal sheet at a thickness of less than 40 μm to enhance the functionality of the porous metal sheet and may function as a membrane separator. The electrochemical device may be used for decomposing molecules and for synthesis of molecules such as synthesis of ammonia from water and nitrogen molecules.

Liu, Wei↗
NASA NTRS1986

Global large scale structures in the F region

Measurements of neutral densities, temperatures and ion density and temperature by the Atmosphere Explorer C and E satellites exhibit fluctuations made up of coherent waves of scale size from hundreds to thousands of kilometers. The fluctuations in the AE-C data are found at times of low magnetic activity to extend from the auroral region in one hemisphere across the equator to the corresponding region in the other hemisphere with little change in apparent wavelength. The fluctuations in the AE-E data similarly exhibit at times of low magnetic activity nearly uniform wave structure encircling the equatorial belt. Typical examples of waves of more than 1000 km apparent wavelength in both the AE-C and AE-E data are presented. These observations during quiet times may be explained by a system of quasi-stationary waves excited by the auroral belts that are distributed about the Earth possibly with tidal or sub-tidal periods and scale lengths determined by the structure of the belts. According to this interpretation, Traveling Ionospheric Disturbance (TID's) are manifestations of transient wave systems moving past a ground observatory that result from changes in magnetic activity with periods and scale sizes associated with the regions of enhanced auroral activity. Some evidence suggesting tidal-like stationary waves from the Millstone Hill incoherent scatter radar is presented.

Gross, S. H.↗
DOE OSTI2015

Adsorptive Separation and Sequestration of Krypton, I and C14 on Diamond Nanoparticles

The objective of this research proposal was to address the separation and sequestration of Kr and I from each other using nano-sized diamond particles and retaining these in diamond until they decay to the background level or can be used as a byproduct. Following removal of Kr and I, an adsorbent will be used to adsorb and store CO 2 from the CO 2 rich stream. A Field Enhanced Diffusion with Optical Activation (FEDOA-a large scale process that takes advantage of thermal, electrical, and optical activation to enhance the diffusion of an element into diamond structure) was used to load Kr and I on micron or nano sized particles having a larger relative surface area. The diamond particles can be further increased by doping it with boron followed by irradiation in a neutron flux. Previous studies showed that the hydrogen storage capacity could be increased significantly by using boron-doped irradiated diamond particles. Diamond powders were irradiated for a longer time by placing them in a quartz tube. The surface area was measured using a Quantachrome Autosorb system. No significant increase in the surface area was observed. Total surface area was about 1.7 m 2 /g. This suggests the existence of very minimal pores. Interestingly it showed hysteresis upon desorption. A reason for this may be strong interaction between the surface and the nitrogen molecules. Adsorption runs at higher temperatures did not show any adsorption of krypton on diamond. Use of a GC with HID detector to determine the adsorption capacity from the breakthrough curves was attempted, but experimental difficulties were encountered.

36 MATERIALS SCIENCE↗