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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 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Introduction to the SPARC Reanalysis Intercomparison Project (S-RIP) and overview of the reanalysis systems

Abstract. The climate research community uses atmospheric reanalysis data sets to understand a wide range of processes and variability in the atmosphere, yet different reanalyses may give very different results for the same diagnostics. The Stratosphere–troposphere Processes And their Role in Climate (SPARC) Reanalysis Intercomparison Project (S-RIP) is a coordinated activity to compare reanalysis data sets using a variety of key diagnostics. The objectives of this project are to identify differences among reanalyses and understand their underlying causes, to provide guidance on appropriate usage of various reanalysis products in scientific studies, particularly those of relevance to SPARC, and to contribute to future improvements in the reanalysis products by establishing collaborative links between reanalysis centres and data users. The project focuses predominantly on differences among reanalyses, although studies that include operational analyses and studies comparing reanalyses with observations are also included when appropriate. The emphasis is on diagnostics of the upper troposphere, stratosphere, and lower mesosphere. This paper summarizes the motivation and goals of the S-RIP activity and extensively reviews key technical aspects of the reanalysis data sets that are the focus of this activity. The special issue The SPARC Reanalysis Intercomparison Project (S-RIP) in this journal serves to collect research with relevance to the S-RIP in preparation for the publication of the planned two (interim and full) S-RIP reports.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Short-time polymerization and convolution kinetics in the analysis of the initiation step of isoprene polymerization over neodymium catalyst

The paper considers a convolution model for polymerization of 1,3-dienes in the presence of organometallic catalysts. It is shown that initial steps of polymerization can be represented as a set of shifted parallel reactions of the chain propagation, in which shift value are governed by the kinetics of the initiation step. In this case, polymer accumulation curve is described by an equation containing convolution of functions which allow one to solve an inverse problem of restoring the function of active site accumulation. Based on the example of isoprene polymerization over neodymium catalyst, it was demonstrated that the results of the inverse problem solution are in good agreement with the experimental data on concentration of the active sites. These data were obtained by a method of controlled introduction of inhibitor in short-time polymerization.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2006

What Do Our Users Want? Perspectives on Understanding and Meeting User Needs for Multi-Mission Data Services

The Sun-Earth Connection Active Archive (SECAA) project of NASA's Space Physics Data Facility operates a range of unique and heavily used multi-mission data services in support of the large-scale science objectives of the Great Observatory, including services such as CDAWeb, the CDAWeb Plus client, SSCWeb, OMNIweb and the CDF data format. In developing and operating these services, we have encountered and continue to struggle with a wide range of issues such as balancing scope and functionality with simplicity and ease of use, understanding the effectiveness of our choices and identifying areas most important for further improvement. In this paper, we will review our key services and then discuss some of our observations and new approaches to understanding and meeting user data service requirements. Some observations are obvious but may still have substantial implications; e.g. functionality without information content is of little user interest, which has led to our recent emphasis on development of web services interfaces, so the content and functionality we already serve is readily and fully available as a building block for new services. Some observations require careful design and tradeoffs; e.g. users will complain when they are offered interfaces with limited options but users are also easily intimidated and become lost when offered extensive options for customization. Some observations remain highly challenging; e.g. a comprehensive multi-mission, multi-source view of all data and services available easily produces a daunting list, but a more selective view can easily lead users to overlook available and relevant data. It is often difficult to obtain and meaningfully interpret measures of true productive usage and overall user satisfaction, even with a variety of techniques including statistics, citations, case studies, user feedback and advisory committees. Most of these issues will apply to and may even be more acute for distributed implementation architectures.

McGuire, Robert E.↗
NASA NTRS2012

An Update on the CDDIS

The Crustal Dynamics Data Inforn1ation System (CoorS) supports data archiving and distribution activities for the space geodesy and geodynamics community. The main objectives of the system are to store space geodesy and geodynamics related data products in a central data bank, to maintain infom1ation about the archival of these data, and to disseminate these data and information in a timely mam1er to a global scientific research community. The archive consists of GNSS, laser ranging, VLBI, and OORIS data sets and products derived from these data. The coors is one of NASA's Earth Observing System Oata and Infom1ation System (EOSorS) distributed data centers; EOSOIS data centers serve a diverse user community and are tasked to provide facilities to search and access science data and products. The coors data system and its archive have become increasingly important to many national and international science communities, in pal1icular several of the operational services within the International Association of Geodesy (lAG) and its project the Global Geodetic Observing System (GGOS), including the International OORIS Service (IDS), the International GNSS Service (IGS), the International Laser Ranging Service (ILRS), the International VLBI Service for Geodesy and Astrometry (IVS), and the International Earth Rotation Service (IERS). The coors has recently expanded its archive to supp011 the IGS Multi-GNSS Experiment (MGEX). The archive now contains daily and hourly 3D-second and subhourly I-second data from an additional 35+ stations in RINEX V3 fOm1at. The coors will soon install an Ntrip broadcast relay to support the activities of the IGS Real-Time Pilot Project (RTPP) and the future Real-Time IGS Service. The coors has also developed a new web-based application to aid users in data discovery, both within the current community and beyond. To enable this data discovery application, the CDDIS is currently implementing modifications to the metadata extracted from incoming data and product files pushed to its archive. This poster will include background information about the system and its user communities, archive contents and updates, enhancements for data discovery, new system architecture, and future plans.

Noll, Carey↗
DOE OSTI2016

Standardization of Geophysical Logging Data at the Hanford Site - 16208

Gamma activity has been measured in boreholes at the US DOE Hanford Site in southeastern Washington State since the 1940's. Over the years, detectors and data recording methods have changed, but the accumulated data provide a record of subsurface gamma activity spanning the period from active operations into interim stabilization. A basic problem is comparability of data between different detectors over a wide range of gamma activity. Many logs are simply presented in terms of raw count rate, and it is difficult to compare count rates between two different detectors, particularly when they have very different response characteristics. The Hanford Gamma Unit (HGU) is proposed as an empirical unit of gamma activity. The HGU is defined in terms of gamma activity at a specified location at the Hanford Borehole Model Facility, and its magnitude is defined such that 1 HGU is approximately equal to typical background gamma activity in uncontaminated soil. The HGU provides a means to convey information about the basic level of subsurface contamination without any implications as to the specific source of the gamma activity. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

FY2021 Progress Report on BISON Metallic Fuel Model Development and V&V Using EBR-II Legacy Data

In this report, the activities and achievements made by Argonne National Laboratory for the Nuclear Energy Advanced Modeling and Simulation (NEAMS) BISON code metallic fuel validation and verification project in FY2021 are summarized. The cladding degradation model based on the FCCI/CCCI wastage calculations has been developed and implemented into BISON. A comprehensive evaluation of the cladding degradation model was performed based on FIPD data of the IFR experiment X447. BISON objects were also developed to enable direct use of time-varying cladding outer surface temperature profile as temperature boundary conditions, which proved to provide more accurate temperature predictions for the metallic fuel pins irradiated in EBR-II. Additionally, a new BISON object was implemented to enable direct comparison between BISON predicted data and FIPD-based post-irradiation examination (PIE) results, which would significantly facilitate BISON metallic fuel verification and validation (V&V) activities. These new BISON-FIPD integration features were used in the establishment of a low-burnup fuel swelling evaluation framework as demonstration. The framework was successfully used to evaluate current fuel swelling models based on the IFR experiment X423.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

A Weakly Supervised Machine Learning Procedure for Magnet Quench Diagnostics

Voltage taps remain the standard and reliable diagnostic tool for detecting quenches in superconducting magnets. However, they identify a quench only at the time of voltage rise and do not provide information on earlier physical precursors. In this work, we investigate whether acoustic emission data can reveal precursor activity that occurs before conventional voltage detection using machine learning techniques. We introduce an event selection method and a weakly supervised machine learning procedure to learn data-driven criteria for identifying potential acoustic precursors to quenches. Two Convolutional Neural Network (CNN) architectures are trained: one on acoustic sensor events from our selection procedure and one on the Fast Fourier Transforms (FFTs) of these events. Both networks are trained iteratively using confidence-weighted loss functions to associate certain subsets of training data with a precursor label. We evaluate the performance of these models by examining the time distribution of events classified as potential precursors relative to the quench onset. Results indicate that the proposed approach can possibly distinguish acoustic emission events occurring closer to the quench from earlier acoustic activity during ramping, suggesting the potential for flagging quench precursors in acoustic data.

Khan, Maira [Fermilab] (ORCID:0009000891602387)↗
NASA NTRS2000

A natural basis for efficient brain-actuated control

The prospect of noninvasive brain-actuated control of computerized screen displays or locomotive devices is of interest to many and of crucial importance to a few 'locked-in' subjects who experience near total motor paralysis while retaining sensory and mental faculties. Currently several groups are attempting to achieve brain-actuated control of screen displays using operant conditioning of particular features of the spontaneous scalp electroencephalogram (EEG) including central mu-rhythms (9-12 Hz). A new EEG decomposition technique, independent component analysis (ICA), appears to be a foundation for new research in the design of systems for detection and operant control of endogenous EEG rhythms to achieve flexible EEG-based communication. ICA separates multichannel EEG data into spatially static and temporally independent components including separate components accounting for posterior alpha rhythms and central mu activities. We demonstrate using data from a visual selective attention task that ICA-derived mu-components can show much stronger spectral reactivity to motor events than activity measures for single scalp channels. ICA decompositions of spontaneous EEG would thus appear to form a natural basis for operant conditioning to achieve efficient and multidimensional brain-actuated control in motor-limited and locked-in subjects.

NASA Discipline Space Human Factors↗
NASA NTRS2018

Birth of a Bipolar Active Region in a Small Coronal Hole

We report on an the emergence of an anemone active region in a very small coronal hole (about 120'' across), beginning at approximately 19:00 UT on March 3, 2016. The emergence was initially observed by an amateur astronomer (RW) in an H-alpha movie from the Global Oscillation Network Group (GONG); it attracted the attention of the observer because there was no active region at the site of the H-alpha brightening. To examine the region in detail, we use data from the Solar Dynamics Observatory (SDO), provided by the Atmospheric Imaging Assembly (AIA) in wavelengths 193 Å, 211 Å, 304 Å, and 94 Å, and with the Helioseismic and Magnetic Imager (HMI). Data analysis and calibration activities such as scaling, rotation so that north is up, and removal of solar rotation are accomplished with SunPy. The emergence seen in HMI data begins with the appearance of a bipole close to the center of the coronal hole, followed by the appearance and growth of a coronal anemone in AIA-EUV images; as the emergence proceeds, the anemone fills the coronal hole in AIA wavelengths. The interchange reconnection of the emerging closed field with ambient open field builds the anemone and shifts the coronal hole from one side of the anemone to the other. Eventually, a sunspot forms in one foot of the emerging field. To date, studies of observations with SDO of anemone emergence in on-disk coronal holes are rare. This bipolar flux emergence episode fits well with the standard picture for the production of coronal-anemone regions.

Adams, Mitzi↗
NASA NTRS1990

The Variation of Solar Fe 14 and Fe 10 Flux over 1.5 Solar Activity Cycles

A new source of data on the solar output, namely limb flux from the one- and two-million degree corona is presented. This parameter is derived from data obtained at the National Solar Observatory at Sacramento Peak with the 40 cm coronagraph of the John W. Evans Solar Facility and the Emission Line Coronal Photometer. The limb flux is defined to be the latitude-averaged intensity in millionths of the brightness of disk center from an annulus of width 1.1 minutes centered at a height of 0.15 solar constant above the limb of emission from lines at 6374A (Fe X) or 5303A (Fe XIV). Fe XIV data have been obtained since 1973 and Fe X since 1984. Examination of the Fe XIV data shows that there is ambiguity in the definition of the last two solar activity minima, which can affect the determination of cycle rise times and lengths. There is an indication that a constant minimum or basal corona may exist at solar minimum. Cycle 22 has had a much faster onset than Cycle 21 and has now overtaken Cycle 21. The rise characteristics of the two cycles were very similar up until Jul. to Aug. 1989, at which time a long-term maximum occurred in Fe X and Fe XIV, which could possibly be the solar maximum. Another maximum is developing at the current time. Cycle 21 was characterized in Fe XIV by at least 4 major thrusts or bursts of activity, each lasting on the order of a year and all having similar maximum limb fluxes which indicates that coronal energy output is sustained over periods in which the sunspot number declines significantly. Dramatic increases in the limb fluxes occur from minimum to maximum, ranging from factors of 14 to 21 in the two lines. Two different techniques to predict the epoch of solar maximum have been applied to the Fe XIV data, resulting in estimates of April 1989 (plus or minus 1 mo) and May 1990 (plus or minus 2 mos).

Altrock, Richard C.↗
DOE OSTI2019

Data-enabled structure–property mappings for lanthanide-activated inorganic scintillators

The use of machine learning (ML) models toward development of validated structure–property relationships for two fundamental properties of activated inorganic scintillators for high energy radiation detection, namely the light yield (LY) and the decay time constant, is explored. The ML models are built on easily accessible proxies of materials—interchangeably referred to as features, descriptors or fingerprints—that are carefully selected on the basis of a physical understanding of the scintillation mechanism. Our study indicates that the developed physics-based ML models employing kernel ridge regression (KRR) and AdaBoost algorithm applied on top of a decision tree-based regression are able to “learn” the underlying design rules in a multi-dimensional feature space and thereby enable reasonably accurate predictions of the two target properties on unseen compounds (i.e., on a held-out test set). For instance, within a set of twenty-five cerium- or europium-doped scintillator materials, our analysis reveals a strong correlation between the average ionic part of the dielectric constant and the LY, irrespective of the specific chemistry of the compounds, indicating that the average ionic part of the dielectric constant is a particularly relevant descriptor toward prediction of the LY. Our results also demonstrate that, despite the use of small training datasets, the developed models are able to quickly distinguish high performing chemistries from those with relatively poor performance and therefore can play a crucial role in screening of new compounds with an attractive combination of targeted properties. Finally, the present study provides necessary motivation for future efforts involving ML models with relatively large training datasets, vast feature space explorations, and experimental design in search of promising novel scintillator chemistries.

36 MATERIALS SCIENCE↗
DOE OSTI2020

IRDFF-II: A New Neutron Metrology Library

High quality nuclear data is the most fundamental underpinning for all neutron metrology applications. This paper describes the release of version II of the International Reactor Dosimetry and Fusion File (IRDFF-II) that contains a consistent set of nuclear data for fission and fusion neutron metrology applications up to 60 MeV neutron energy. The library is intended to support: a) applications in research reactors; b) safety and regulatory applications in the nuclear power generation in commercial fission reactors; and c) material damage studies in support of the research and development of advanced fusion concepts. The paper describes the contents of the library, documents the thorough verification process used in its preparation, and provides an extensive set of validation data gathered from a wide range of neutron benchmark fields. The new IRDFF-II library includes 119 metrology reactions, four cover material reactions to support self-shielding corrections, five metrology metrics used by the dosimetry community, and cumulative fission products yields for seven fission products in three different neutron energy regions. In support of characterizing the measurement of the residual nuclei from the dosimetry reactions and the fission product decay modes, the present document lists the recommended decay data, particle emission energies and probabilities for 68 activation products. It also includes neutron spectral characterization data for 29 neutron benchmark fields for the validation of the library contents. Additional six reference fields were assessed (four from plutonium critical assemblies, two measured fields for thermal-neutron induced fission on 233U and 239Pu targets) but not used for validation due to systematic discrepancies in C/E reaction rate values or lack of reaction-rate experimental data. Another ten analytical functions are included that can be useful for calculating average cross sections, average energy, thermal spectrum average cross sections and resonance integrals. The IRDFF-II library and comprehensive documentation is available online at www-nds.iaea.org/IRDFF/. Evaluated cross sections can be compared with experimental data and other evaluations at www-nds.iaea.org/exfor/endf.htm. The new library is expected to become the international reference in neutron metrology for multiple applications.

IAEA IRDFF↗
DOE OSTI2017

Nanoquinacrine caused apoptosis in oral cancer stem cells by disrupting the interaction between GLI1 and β catenin through activation of GSK3β

Presences of cancer stem cells (CSCs) in a bulk of cancer cells are responsible for tumor relapse, metastasis and drug resistance in oral cancer. Due to high drug efflux, DNA repair and self-renewable capacity of CSCs, the conventional chemotherapeutic agents are unable to kill the CSCs. CSCs utilizes Hedgehog (HH-GLI), WNT-β catenin signalling for its growth and development. GSK3β negatively regulates both the pathways in CSCs. Here, we have shown that a nano-formulated bioactive small molecule inhibitor Quinacrine (NQC) caused apoptosis in oral cancer stem cells (OCSCs; isolated from different oral cancer cells and oral cancer patient derived primary cells) by down regulating WNT-β catenin and HH-GLI components through activation of GSK3β. NQC activates GSK3β in transcriptional and translational level and reduces β catenin and GLI1 as well as downstream target gene of both the pathways Cyclin D1, C-Myc. The transcription factor activity of both the pathways was also reduced by NQC treatment. GSK3β, β catenin and GLI1 interacts with each other and NQC disrupts the co-localization and interaction between β catenin and GLI1 in OCSCs in a dose dependent manner through activation of GSK3β. Thus, data suggest NQC caused OCSCs death by disrupting the crosstalk between β catenin and GLI1 by activation of GSK3β. - Graphical abstract: Schematic representation of inhibition of HH-GLI and WNT-β catenin cross talk by NQC through GSK3β. Diagram showing HH-GLI and WNT-β catenin pathway, where GLI1 and β catenin and other components were co-localized in a complex and co-ordinately regulate the downstream target genes. NQC activates GSK3β, which further phosphorylates and activates the β catenin and GLI1. Activated β catenin and GLI1 were degraded by proteosomal degradation pathway and unable to translocate into nucleus as a result growth of cells inhibited. - Highlights: • Nano-formulated quinacrine (NQC) activates GSK3β in oral cancer stem cells (OCSCs) in vitro and ex vivo. • NQC induces apoptosis in OCSCs by inhibiting WNT-β catenin and HH-GLI cascade in vitro and ex vivo. • NQC disrupts the interaction and co-localization between GLI1 and β catenin. • NQC-mediated disruption of the crosstalk between GLI1 and β catenin is GSK3β dependent.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

CHROMOSPHERIC MASS MOTIONS AND INTRINSIC SUNSPOT ROTATIONS FOR NOAA ACTIVE REGIONS 10484, 10486, AND 10488 USING ISOON DATA

This work utilizes Improved Solar Observing Optical Network continuum (630.2 nm) and H{alpha} (656.2 nm) data to: (1) detect and measure intrinsic sunspot rotations occurring in the photosphere and chromosphere, (2) identify and measure chromospheric filament mass motions, and (3) assess any large-scale photospheric and chromospheric mass couplings. Significant results from 2003 October 27-29, using the techniques of Brown et al., indicate significant counter-rotation between the two large sunspots in NOAA AR 10486 on October 29, as well as discrete filament mass motions in NOAA AR 10484 on October 27 that appear to be associated with at least one C-class solar flare.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Comparison of two different methods of image analysis for the assessment of microglial activation in patients with multiple sclerosis using (R)-[N-methyl-carbon-11]PK11195

Chronic active multiple sclerosis (MS) lesions have a rim of activated microglia/macrophages (m/M) leading to ongoing tissue damage, and thus represent a potential treatment target. Activation of this innate immune response in MS has been visualized and quantified using PET imaging with [ 11C]-(R)-PK11195 (PK). Accurate identification of m/M activation in chronic MS lesions requires the sensitivity to detect lower levels of activity within a small tissue volume. We assessed the ability of kinetic modeling of PK PET data to detect m/M activity in different central nervous system (CNS) tissue regions of varying sizes and in chronic MS lesions. Ten patients with MS underwent a single brain MRI and two PK PET scans 2 hours apart. Volume of interest (VOI) masks were generated for the white matter (WM), cortical gray matter (CGM), and thalamus (TH). The distribution volume (VT) was calculated with the Logan graphical method (LGM-VT) utilizing an image-derived input function (IDIF). The binding potential (BPND) was calculated with the reference Logan graphical method (RLGM) utilizing a supervised clustering algorithm (SuperPK) to determine the non-specific binding region. Masks of varying volume were created in the CNS to assess the impact of region size on the various metrics among high and low uptake regions. Chronic MS lesions were also evaluated and individual lesion masks were generated. The highest PK uptake occurred the TH and lowest within the WM, as demonstrated by the mean time activity curves. In the TH, both reference and IDIF based methods resulted in estimates that did not significantly depend on VOI size. However, in the WM, the test-retest reliability of BPND was significantly lower in the smallest VOI, compared to the estimates of LGM-VT. These observations were consistent for all chronic MS lesions examined. In this study, we demonstrate that BPND and LGM-VT are both reliable for quantifying m/M activation in regions of high uptake, however with blood input function LGM-VT is preferred to assess longitudinal m/M activation in regions of relatively low uptake, such as chronic MS lesions.

60 APPLIED LIFE SCIENCES↗