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At least 1,261 records · Page 70

Data and Reasoning Fabric (DRF) Video 2

The Data & Reasoning Fabric activity, under the Convergent Aeronautics Solutions (CAS) Project has developed a video, suitable for public release.

Data Reasoning↗

Concerted Proton–Electron Transfer Minimizes Substituent Effects on Adsorbed Phthalocyanine Electrocatalysis

Molecularly modified electrodes (MMEs) are potent electrocatalysts, but few principles exist for their rational design. Electrocatalysis by soluble molecules depends strongly on substituents that tune the catalyst redox potential (E 1/2 ), but it is unclear if this parameter similarly impacts MME catalysis. Herein, we employ the hydrogen evolution reaction (HER) as a test case for comparing carbon-adsorbed cobalt phthalocyanine (CoPc/C) and cobalt hexadecafluoro-phthalocyanine (CoFPc/C). By correlating HER activity and voltammetric data to total Co surface concentration across a wide range of catalyst loadings, we find that only 5–25% of adsorbed Co sites contribute to the Co(II/I) redox wave and that this subpopulation poorly correlates with catalytic activity. Instead, in the low-loading limit, catalytic activity correlates linearly with the majority Co(II/I)-silent Co population, revealing per-site turnover frequency (TOF) values for HER. Despite a 230 mV difference in Co(II/I) redox potentials, CoPc/C and CoFPc/C display TOF values differing by less than a factor of 3 when compared over a wide potential range. Mechanistic studies point to an inner-sphere concerted proton–electron transfer step as rate-determining, suggesting that the Co–H bond dissociation free energy (BDFE) rather than the Co(II/I) E 1/2 is thermodynamically relevant. Computational studies indicate that the fluoro-substituents lead to compensatory changes in Co(II/I) E 1/2 and Co(I) basicity, leaving the Co–H BDFE largely unchanged between CoPc and CoFPc and thereby manifesting in similar catalytic rates. Furthermore, these results highlight the limited effect of E 1/2 -tuning on MME catalytic activity and motivate the development of methods to directly alter active site–substrate BDFE.

Catalysts↗

Modeling household-level party composition behavior for multiparty activities: a random parameter nested logit modeling approach

This study presents findings of a household-level party composition model for multiparty activities. It exploits data from a comprehensive Household Travel Survey conducted by Chicago Metropolitan Agency of Planning. The study estimates a random parameter nested logit model to capture households’ unobserved preference heterogeneity and non-proportional substitution patterns in terms of activity party composition for multiparty activities. A wide variety of household demographics, activity attributes and residential neighborhood characteristics are examined in this paper. The magnitude of the impacts of the determinants are tested in this study by analyzing the elasticity of the variables, which suggests that household demographics and attributes of the multiparty activities have significant effects on the household-level activity party composition. Residential neighborhood characteristics, although somewhat less impactful, still play a meaningful role. This model will be implemented within the POLARIS transportation systems simulator to improve the activity generation modeling workflow, and the prediction accuracy of various activity-travel components.

activity party composition↗

Analysis of an Anemone-Type Eruption in an On-Disk Coronal Hole

We report on an eruption seen in a very small coronal hole (about 120 arcseconds across), beginning at approximately 19:00 Universal Time on March 3, 2016. The event was initially observed by an amateur astronomer (RW) in an H-alpha movie from the Global Oscillation Network Group (GONG); the eruption attracted the attention of the observer because there was no nearby active region. 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 angstroms, 304 angstroms, and 94 angstroms, and 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 eruption in low-cadence HMI data begins with the appearance of a bipole in the location of the coronal hole, followed by (apparent) expansion outwards when the intensity of the AIA wavelengths brighten; as the event proceeds, the coronal hole disappears. From high-cadence data, we will present results on the magnetic evolution of this structure, how it is related to intensity brightenings seen in the various SDO/AIA wavelengths, and how this event compares with the standard-anemone picture.

anemone↗

Isopiestic measurements of thermodynamic properties for the aqueous system LiBr–CaBr 2 –H 2 O at 373.15 K

In this study, the isopiestic molalities for the systems LiBr–H 2 O, CaBr 2 –H 2 O and LiBr–CaBr 2 –H 2 O were measured at 373.15 K with the isopiestic method using the Oak Ridge National Laboratory (ORNL) high–temperature gravimetric isopiestic apparatus. The osmotic coefficients were determined based on the lithium chloride and sodium chloride reference standards. The vapor pressure diagrams and osmotic coefficient diagrams at different mole fraction for LiBr were plotted. The calculated vapor pressure with water activities agree well with the experimental data. On the basis of Pitzer original and its extended model, the Pitzer binary parameters β (0) , β (1) C (0) and C (1) for the systems LiBr–H 2 O and CaBr 2 –H 2 O and mixing parameters of θ Li,Ca and ψ Li,Ca,Br were fitted with the measured osmotic coefficients. The calculated osmotic coefficients for systems LiBr–H 2 O and CaBr 2 –H 2 O agree well with the experimental data. The agreement between the calculated water activities and experimental results for the ternary system indicates that the parameters obtained in this work are reliable for water activity calculation. Finally, the thermodynamic data obtained in this study are essential for development of universal thermodynamic models for brine systems containing lithium bromide and calcium bromide.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Microtopographic and Depth Controls on Active Layer Chemistry in Arctic Polygonal Ground: Supporting Data

Polygonal ground is a signature characteristic of the Arctic, and permafrost thaw can potentially generate substantial feedbacks to Arctic ecosystems and climate. This study describes the first comprehensive spatial examination of active layer biogeochemistry that extends across high- and low-centered polygons and their features, including depth. Water chemistry measurements were made on active layer water samples collected near Barrow, Alaska during summer, 2012. Several significant differences in chemistry were observed between high- and low-centered polygons suggesting polygon types may be useful for landscape-scale geochemical classification. However, differences were found for polygon features (centers and troughs) for analytes that were not significant for type, suggesting that finer scale features control biogeochemistry in a different way than polygon type. Depth variations were also significant, demonstrating important multi-dimensional aspects of polygonal ground biogeochemistry. These results have major implications for understanding how polygonal ground ecosystems function, and how they may respond to future change. This data package includes one *.csv data file and one *.pdf user guide. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗

SU-G-201-03: Automation of High Dose Rate Brachytherapy Quality Assurance: Development of a Radioluminescent Detection System for Simultaneous Detection of Activity, Timing, and Positioning

Purpose: Accuracy of positioning, timing and activity is of critical importance for High Dose Rate (HDR) brachytherapy delivery. Respective measurements via film autoradiography, stop-watches and well chambers can be cumbersome, crude or lack dynamic source evaluation capabilities. To address such limitations, a single device radioluminescent detection system enabling automated real-time quantification of activity, position and timing accuracy is presented and experimentally evaluated. Methods: A radioluminescent sheet was fabricated by mixing Gd?O?S:Tb with PDMS and incorporated into a 3D printed device where it was fixated below a CMOS digital camera. An Ir-192 HDR source (VS2000, VariSource iX) with an effective active length of 5 mm was introduced using a 17-gauge stainless steel needle below the sheet. Pixel intensity values for determining activity were taken from an ROI centered on the source location. A calibration curve relating intensity values to activity was generated and used to evaluate automated activity determination with data gathered over 6 weeks. Positioning measurements were performed by integrating images for an entire delivery and fitting peaks to the resulting profile. Timing measurements were performed by evaluating source location and timestamps from individual images. Results: Average predicted activity error over 6 weeks was .35 ± .5%. The distance between four dwell positions was determined by the automated system to be 1.99 ± .02 cm. The result from autoradiography was 2.00 ± .03 cm. The system achieved a time resolution of 10 msec and determined the dwell time to be 1.01 sec ± .02 sec. Conclusion: The system was able to successfully perform automated detection of activity, positioning and timing concurrently under a single setup. Relative to radiochromic and radiographic film-based autoradiography, which can only provide a static evaluation positioning, optical detection of temporary radiation induced luminescence enables dynamic detection of position enabling automated quantification of timing with millisecond accuracy.

60 APPLIED LIFE SCIENCES↗

The Use of the CCSDS Unified Space Data Link Protocol on All Space Links

NASA is actively pursuing the development of data link layer protocols for the human space program with the added intent of infusing the key capabilities of efficient space link security, support for inter-networking, and compatible operational modes with Optical Communications. There seems to be two divergent technical approaches on how to provide these capabilities: one associated with the use of a fixed length Protocol Data Unit (PDU) i.e., a fixed length transfer frame, and the other advocating the use of a variable length transfer frame. The objective of this paper is to evaluate the pros and cons of these two approaches within the context of existing Consultative Committee for Space Data Systems (CCSDS) Space Data Link Protocols and Channel Coding Recommendations for all space links: space to ground (return) link, ground to space (forward) link and space to space (proximity) links.

Kazz, Greg J↗

Coupled Long-Term Experiment and Model Investigation of the Differential Response of Plants and Soil Microbes in a Changing Permafrost Tundra Ecosystem

The major research goal of this project was to understand and quantify the fate of carbon stored in permafrost ecosystems using a combination of field and laboratory experiments to measure and model isotope ratios and carbon fluxes in a tundra ecosystem exposed to experimental warming. Field measurements centered on a two-factor experimental warming to increase air and soil temperatures alone, and in combination, at a tundra field site in Alaska. A second manipulation of water table was embedded within the warming treatment such that both major environmental factors (temperature, moisture) controlling ecosystem carbon dynamics were experimentally altered. The experiment was interfaced with modeling activities using both data assimilation and forward modeling approaches. Models were used to make forecasts of ecosystem carbon dynamics beyond the time frame and environmental space of the experiment itself. This project was a follow-on to previous work that made use of the same field manipulation; here we continued the experimental manipulation in order to test new hypotheses regarding long-term effects of warming and permafrost thaw and subsequent changes in moisture availability on ecosystem carbon dynamics. These results were linked with ongoing synthesis and model intercomparison activities through the Permafrost Carbon Network, which led to additional synthesis publications as a result of collaboration and data sharing from this project. As key outcomes, this project has produced new papers published in the peer-reviewed literature, archived datasets used for model-data intercomparisons, trained graduate students and postdoctoral researchers, and has raised awareness about the vulnerability of permafrost carbon to a wider audience.

54 ENVIRONMENTAL SCIENCES↗

Active Learning Meets Foundation Models: Fast Remote Sensing Data Annotation for Object Detection

Object detection in remote sensing demands extensive, high-quality annotations—a process that is both labor-intensive and time-consuming. In this work, we introduce a real-time active learning and semi-automated labeling framework that leverages foundation models to streamline dataset annotation for object detection in remote sensing imagery. For example, by integrating a Segment Anything Model (SAM), our approach generates mask-based bounding boxes that serve as the basis for dual sampling: (a) uncertainty estimation to pinpoint challenging samples, and (b) diversity assessment to ensure broad data coverage. Furthermore, our Dynamic Box Switching Module (DBS) addresses the well-known cold start problem for object detection models by replacing its suboptimal initial predictions with SAM-derived masks, thereby enhancing early-stage localization accuracy. Extensive evaluations on multiple remote sensing datasets plus a real-world user study, demonstrate that our framework not only reduces annotation effort, but also significantly boosts detection performance compared to traditional active learning sampling methods. The code for training and the user interface will be made available.

Burges, Marvin [ORNL] (ORCID:0000000312690769)↗

Project Grandmaster

The purpose of the Project Grandmaster Application is to allow individuals to opt-in and give the application access to data sources about their activities on social media sites. The application will cross-reference these data sources to build up a picture of each individual activities they discuss, either at present or in the past, and place this picture in reference to groups of all participants. The goal is to allow an individual to place themselves in the collective and to understand how their behavior patterns fit with the group and potentially find changes to make, such as activities they weren't already aware of or different groups of interest they might want to follow.

Source record↗

MODIS Science Team Member Semi-annual Report

This paper presents a semi-annual report of the MODerate resolution imaging Spectroradiometer (MODIS) Science Team Members. The most important activities undertaken during this reporting period are the following: 1) Versions 2.1 and 2.2 surface reflectance L2/L3 DAAC/SDST delivery; 2) Version 2.0 1km and 250m VI product delivery (assist Arizona); 3) Version 2.1 surface reflectance L2 testing; 4) Land Synthetic data set generator improvements; 5) QA; 6) Surface reflectance error budget generation (SWAMP request); 7) SCF Hardware; 8) Aerosol transport modeling; 9) Aerosol optical depth retrieval from AVHRR data; 10) Aerosol characteristics retrieval from SeaWIFS/AVHRR fusioned data; 11) Validation activities; 12) Aerosol climatology; and 13) 6S code. The report includes summaries of the topics above.

Vermote, Eric↗

Science Data Processing for the Advanced Microwave Scanning Radiometer: Earth Observing System

The National Aeronautics and Space Administration established the framework for the Science Investigator-led Processing Systems (SIPS) to enable the Earth science data products to be produced by personnel directly associated with the instrument science team and knowledgeable of the science algorithms. One of the first instantiations implemented for NASA was the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) SIPS. The AMSR-E SIPS is a decentralized, geographically distributed ground data processing system composed of two primary components located in California and Alabama. Initial science data processing is conducted at Remote Sensing Systems (RSS) in Santa Rosa, California. RSS ingests antenna temperature orbit data sets from JAXA and converts them to calibrated, resampled, geolocated brightness temperatures. The brightness temperatures are sent to the Global Hydrology and Climate Center in Huntsville, Alabama, which generates the geophysical science data products (e.g., water vapor, sea surface temperature, sea ice extent, etc.) suitable for climate research and applications usage. These science products are subsequently sent to the National Snow and Ice Data Center Distributed Active Archive Center in Boulder, Colorado for archival and dissemination to the at-large science community. This paper describes the organization, coordination, and production techniques employed by the AMSR-E SIPS in implementing, automating and operating the distributed data processing system.

Goodman, H. Michael↗

Project Grandmaster

The purpose of the Project Grandmaster Application is to allow individuals to opt-in and give the application access to data sources about their activities on social media sites. The application will cross-reference these data sources to build up a picture of each individual activities they discuss, either at present or in the past, and place this picture in reference to groups of all participants. The goal is to allow an individual to place themselves in the collective and to understand how their behavior patterns fit with the group and potentially find changes to make, such as activities they weren't already aware of or different groups of interest they might want to follow.

Source record↗

Evaluating Age Effects on HEPA Filter Performance

Nuclear grade high efficiency particulate air (HEPA) filters are routinely employed as the final control element in confinement ventilation systems. The traditional HEPA filter utilizes a pleated filter medium of fibrous glass that has been produced in a manner analogous to manufacturing paper. These filters are the physically weakest element in a containment ventilation system. Containment ventilation systems are designed to condition the air-stream (temperature, relative humidity, moisture, particle size distribution of aerosols, and aerosol concentration) to levels/conditions that fibrous glass HEPA filters can handle. Approximately 6000 nuclear grade HEPA filters are purchased each year for use in the DOE/NNSA complex. Additional filters are purchased for use in commercial nuclear power generation and ventilation systems of other nuclear applications. These filters are designed and tested in accordance with the American Society of Mechanical Engineers (ASME) AG-1 Code Nuclear Air and Gas Treatment. This code establishes design requirements and qualification procedures. Qualification testing of axial flow filters is described in paragraphs 5000 and following of AG-1. The series of qualification tests are intended to describe the operating envelope of HEPA filters and verify the reliability of a filter design. AG-1 qualification also confirms the pedigree of components used in manufacture for that filter design. The collective set of qualification tests establishes the assumed operating envelope for AG-1 filters. The effects of age on HEPA filter performance have been a concern for at least two decades. A combination of physical evaluation of aged filter media and a review of filter failure records resulted in Appendix C of the Nuclear Air Cleaning Handbook (NACH), Determination of HEPA Filter Life. This states that HEPA filters are not to be used beyond 10 years from the date of manufacture. Additionally, filters put into service in locations where they may become wet are to be taken out of service five years from date of manufacture. Filters that have become wet are to be taken out of service immediately. Finally, it should also be pointed out that filters held in Level B storage are subject to the same 10-year service life. Very limited bench-scale testing in the 1990's raised concern that aging HEPA filters do not have the strength to withstand an accident scenario. In May of 1999, the DNFSB released a Technical Report 23 entitled HEPA Filters Used in the Department of Energy's Hazardous Facilities. This report expressed concerns for the potential vulnerability of HEPA filters in vital safety systems. Concerns and uncertainty associated with degradation of HEPA filter performance over time led the DOE sites to limit HEPA filter service life to 10 years from the date of manufacture or five years in cases where filters may become wet. Establishment of a conservative service life needs to be based on data from a structured series of tests comparing the performance envelope of new and aged full-scale filters. A service life that is insufficiently conservative endangers workers and the public. One that is excessively conservative costs can cause hundreds of otherwise unnecessary filter changes. This increases exposure of employees, disrupts facility operations, and increase disposal costs by millions of dollars annually. Conclusive data are needed to resolve uncertainty associated with the damaging effects of aging on durability of HEPA filters. Therefore, this study needs to provide a sufficient body of evidence to allow DOE and site professionals to make prudent decisions. An updated version of ASME AG-1 Section FC included a non-mandatory appendix that would include the DOE guidance for service life of HEPA filters. Balloting of this revision generated significant resistance to inclusion of any kind of service life language citing the lack of supporting experimental data. Efforts to resolve negative votes failed and resistance to acceptance of the language increased. The result has been to not include service language in Section FC and requests to remove it from sections that already include such language. The recent activity of the ASME AG-1 Committee on Nuclear Air and Gas Treatment effectively de-emphasizes following DoE's service life guidelines. The DOE Office of Nuclear Safety under its NSR and D program provided the Mississippi State University Institute for Clean Energy Technology (ICET) finding to initiate a study to determine the effects of aging on AG-1 axial flow filters just prior to actions taken within the AG-1 committee regarding service life. The NSR and D funding facilitated timely development of a national technical working group comprised of members from the regulatory community, DOE complex, and commercial power to resolve uncertainty associated with effects of aging. The Department of Energy Office of Environmental Management (DOE-EM) has been funding the ICET to evaluate the performance envelope for AG-1 HEPA filters. ICET is one of DOE-EM's qualified suppliers. Synergy has been achieved by associating the NSR and D aged filter activities to testing activities evaluating the performance envelopes of separator and separator-less AG-1 HEPA filters funded by DOE-EM. The DOE-EM funded activities establish baseline data for the aged filter study and future EM funding will provide long term support for testing additional aged filters. EM funding of new filters includes analytical evaluation of media tensile strength by thermal analysis to establish baseline values and determine mass loss of moisture resistance and acrylic binders due to use. All of these values can be used for comparison of test results for aged filters. (authors)

07 ISOTOPE AND RADIATION SOURCES↗

Using automated machine learning for the upscaling of gross primary productivity

Estimating gross primary productivity (GPP) over space and time is fundamental for understanding the response of the terrestrial biosphere to climate change. Eddy covariance flux towers provide in situ estimates of GPP at the ecosystem scale, but their sparse geographical distribution limits larger-scale inference. Machine learning (ML) techniques have been used to address this problem by extrapolating local GPP measurements over space using satellite remote sensing data. However, the accuracy of the regression model can be affected by uncertainties introduced by model selection, parameterization, and choice of explanatory features, among others. Recent advances in automated ML (AutoML) provide a novel automated way to select and synthesize different ML models. In this work, we explore the potential of AutoML by training three major AutoML frameworks on eddy covariance measurements of GPP at 243 globally distributed sites. We compared their ability to predict GPP and its spatial and temporal variability based on different sets of remote sensing explanatory variables. Explanatory variables from only Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data and photosynthetically active radiation explained over 70 % of the monthly variability in GPP, while satellite-derived proxies for canopy structure, photosynthetic activity, environmental stressors, and meteorological variables from reanalysis (ERA5-Land) further improved the frameworks' predictive ability. We found that the AutoML framework Auto-sklearn consistently outperformed other AutoML frameworks as well as a classical random forest regressor in predicting GPP but with small performance differences, reaching an r 2 of up to 0.75. We deployed the best-performing framework to generate global wall-to-wall maps highlighting GPP patterns in good agreement with satellite-derived reference data. This research benchmarks the application of AutoML in GPP estimation and assesses its potential and limitations in quantifying global photosynthetic activity.

54 ENVIRONMENTAL SCIENCES↗

Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations: Data used in Geosphere Journal Article

This data submission is for Phase 2 of Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations, which focuses on multi-fluid (CO2 and brine) geothermal energy production and diurnal bulk energy storage in geologic settings that are suitable for geologic CO2 storage. This data submission includes all data used in the Geosphere Journal article by Buscheck et al (2016). All assumptions are discussed in that article.

15 GEOTHERMAL ENERGY↗