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At least 325 records · Page 18

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DOE OSTI2026

Sampling Microbial Dynamics in the Salish Sea Estuary: Evaluating Methods to Capture Cyanobacteria and Cyanophage

Introduction: Picocyanobacteria from the genera Prochlorococcus and Synechococcus thrive across the globe in aquatic environments, have relatively small genomes, and have growth dynamics regulated by both viral interactions and abiotic conditions, making them excellent model organisms for exploring host-pathogencoevolution. Methods: We developed and refined methods to sample and sequence cyanobacteria, cyanophages, and measured features of their abiotic environment. Results: The protocol described herein can successfully discriminate large-cell eukaryotic organisms, but size fractionation of picocyanobacteria appears to be affected by the presence of free DNA, multicellular structures, and abundant tycheposons. Our preferred final protocol from this exploratory effort included a combination of in-line and single vacuum flask filtrations, which reduced filtration processing time by over threefold in some cases compared to other tested methods, such as a fully in-line sequence or in-site filtrations. We successfully extracted an average of approximately 400–1200 ng for all filter fractions, with some variations between kits. Discussion: The protocol described herein can successfully discriminate large-cell eukaryotic organisms, but size fractionation of picocyanobacteria appears to be affected by the presence of free DNA, multicellular structures, and abundant tycheposons.

Salish Sea↗

DOE OSTI2025

Ecohydrological controls on root and microbial respiration in the East River watershed of Colorado

The main objective of this project was to conduct exploratory work to quantify how snow and rain water inputs influence the CO2 coming from the soil surface (soil CO2 flux), and its plant and microbial sources, in the East River watershed, near Crested Butte, Colorado. Knowledge gained from this effort laid the groundwork for a more comprehensive (ongoing) follow-on grant that is using a combination of experiments, field observations, machine learning and simulation modeling to fully disentangle these relationships. New field measurements were made at four locations along an elevational transect on Snodgrass Mountain at Rocky Mountain Biological Laboratory. These sites were chosen to differ in total snowpack and water table depth, and included both deciduous (aspen) and evergreen (spruce/fir) forest types. We used automated measurements of soil CO2 concentrations to quantify the total soil CO2 flux, and the vertical CO2 production within the soil profile at each site. Isotope (radiocarbon, 14C) measurements determined how much of the CO2 emitted from the soil surface came from plant respiration (root metabolism) versus microbial respiration (decomposition of soil organic matter) sources. Supporting data on plant phenology and microbial dynamics provided context for the observed variation in respiration sources. This work was motivated by our overarching hypothesis that quantifying belowground plant and microbial processes separately, and how they are influenced by snow and rain inputs, is necessary for understanding and predicting how the East River watershed ecosystems will respond to future environmental change.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS2006

Exploratory Studies in Generalized Predictive Control for Active Gust Load Alleviation

The results of numerical simulations aimed at assessing the efficacy of Generalized Predictive Control (GPC) for active gust load alleviation using trailing- and leading-edge control surfaces are presented. The equations underlying the method are presented and discussed, including system identification, calculation of control law matrices, and calculation of commands applied to the control effectors. Both embedded and explicit feedforward paths for inclusion of disturbance effects are addressed. Results from two types of simulations are shown. The first used a 3-DOF math model of a mass-spring-dashpot system subject to user-defined external disturbances. The second used open-loop data from a wind-tunnel test in which a wing model was excited by sinusoidal vertical gusts; closed-loop behavior was simulated in post-test calculations. Results obtained from these simulations have been decidedly positive. In particular, results of closed-loop simulations for the wing model showed reductions in root moments by factors as high as 1000, depending on whether the excitation is from a constant- or variable-frequency gust and on the direction of the response.

Kvaternik, Raymond G.↗

DOE OSTI2023

Psychometric property study of the Affective Lability Scale-short form in Chinese patients with mood disorders

Introduction This study aimed to investigate the psychometric properties of the Affective Lability Scale-short form (ALS-SF) among Chinese patients with mood disorders, and to compare ALS-SF subscale scores between patients with major depressive disorder (MDD) and patients with bipolar disorder (BD) depression. Methods A total of 344 patients with mood disorders were included in our study. Participants were measured through a set of questionnaires including the Chinese version of ALS-SF, Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder 7-item (GAD-7), and NEO-Five Factor Inventory (NEO-FFI). Exploratory factor analysis and confirmatory factor analysis were applied to examine the psychometric properties of ALS-SF. Besides, correlation and regression analyses were performed to explore the relationship between affective lability and depression, anxiety, and neuroticism. Independent samples t -tests were used to compare the subscale scores of ALS-SF between the MDD and BD depression groups. Results Results of factor analysis indicated that the model of ALS-SF was consistent with ALS-SF. The ALS-SF showed a solid validity and high internal consistency (Cronbach’s alpha = 0.861). In addition, each subscale of ALS-SF was significantly correlated with PHQ-9, GAD-7, and NEO-FFI neuroticism subscale, except for the anger subscale showed no significant correlation with PHQ-9. Besides, the depression/elation and anger factor scores in patients with BD depression were higher than in patients with MDD. Conclusion Our study suggests that the Chinese version of ALS-SF has good reliability and validity for measuring affective lability in Chinese patients with mood disorders. Assessing affective lability would assist clinicians to distinguish between MDD and BP depression and may decrease the risks of misdiagnosis.

Ma, Mohan↗

DOE OSTI2021

Understanding implications of cathode architecture on energy density of solid-state batteries

Next generation solid-state batteries (SSB) will need to leverage high voltage cathodes, as well as metallic anodes to achieve the realistic performance targets necessary to replace liquid electrolyte-based batteries in cutting-edge applications including electric vehicles. However, limitations arising from mass and charge transports, kinetics and chemo-mechanical degradation at the electrode | electrolyte interface limit the performance of present day SSBs. Optimizing composite cathode architecture, which is an integral part of solid-state batteries, is vital to realize the high-energy density and high-performance goals for next-generation solid-state batteries. Additionally, cathode architecture needs to be optimized for high loadings of active material, well-percolated ion and electron transport pathways and increased resilience against electrochemical stresses. This paper provides a first report of framework for geometric modeling of composite cathode architectures and evaluates the impact of cathode architecture on cell-level energy density using hierarchical models. Packing around primary and secondary active material particles are simulated for a range of active material particle size and solid electrolyte size distributions in the composite cathode. Impact of packing architecture on processing parameters of a given cathode composition and thickness, as well as on achievable energy density is evaluated for a range of commonly used solid electrolyte and cathode materials. Overall, the proposed framework offers a facile exploratory methodology for establishing initial metrics for scalable processing of practical and competent SSBs.

25 ENERGY STORAGE↗

NASA NTRS1964

Experimental Data on Stagnation-Point Gas Injection Cooling on a Hemisphere-Cone in a Hypersonic Arc Tunnel

Exploratory tests were made to determine the reduction of heat transfer resulting from ejection of gases at the stagnation point on a hemisphere-cone at a nominal Mach number of about 9 and at stagnation enthalpies up to 1600 BTU per pound. Helium, nitrogen, and argon gases were used as coolants. The ratio of mass flow of coolant to the mass flow of air swept out by the model projected area was less than 0.20 in all cases. The experimental heat-transfer data were normalized by the calculated stagnation-point values based on test conditions in the tunnel and are presented as a function of the surface distance from the stagnation point. The variation of shock standoff distances with mass flow and volumetric flow of the gaseous ejectants is presented along with photographs of the luminous flow field of the model during tests.

STAGNATION FLOW↗

NASA NTRS1975

Satellite-sized planetesimals and lunar origin

Exploratory calculations using accretionary theory are made to demonstrate plausible sizes of second-largest, third-largest, etc., bodies at the close of planet formation in heliocentric orbits near the planets, assuming asteroid-like size distributions at the start of the calculation. Many satellite-sized bodies are found to be available for capture, cratering, or collisional fragmentation. In the case of earth-sized planets, the models suggest second-largest bodies of 500 to 3000 km radius, and tens of bodies larger than 100 km radius. Many of these interact with the planet before suffering any fragmentation events with each other. Collision of a large body with earth could eject iron-deficient crust and upper mantle material, forming a cloud of refractory, volatile-poor dust that could form the moon. Other satellite systems may have been affected by major capture or collision events of chance character.

Hartmann, W. K.↗

NASA NTRS2012

A Computational Investigation of Gear Windage

A CFD method has been developed for application to gear windage aerodynamics. The goals of this research are to develop and validate numerical and modeling approaches for these systems, to develop physical understanding of the aerodynamics of gear windage loss, including the physics of loss mitigation strategies, and to propose and evaluate new approaches for minimizing loss. Absolute and relative frame CFD simulation, overset gridding, multiphase flow analysis, and sub-layer resolved turbulence modeling were brought to bear in achieving these goals. Several spur gear geometries were studied for which experimental data are available. Various shrouding configurations and free-spinning (no shroud) cases were studied. Comparisons are made with experimental data from the open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility. The results show good agreement with experiment. Interrogation of the validative and exploratory CFD results have led, for the first time, to a detailed understanding of the physical mechanisms of gear windage loss, and have led to newly proposed mitigation strategies whose effectiveness is computationally explored.

Hill, Matthew J.↗

DOE OSTI2023

Exposure to multiple ion beams, broadly representative of galactic cosmic rays, causes perivascular cardiac fibrosis in mature male rats

Long-duration space exploratory missions to the Earth’s moon and the planet Mars are actively being planned. Such missions will require humans to live for prolonged periods beyond low earth orbit where astronauts will be continuously exposed to high energy galactic cosmic rays (GCRs). A major unknown is the potential impact of GCRs on the risks of developing degenerative cardiovascular disease, which is a concern to NASA. A ground-based rat model has been used to provide a detailed characterization of the risk of long-term cardiovascular disease from components of GCRs at radiation doses relevant to future human missions beyond low earth orbit. Six month old male WAG/RijCmcr rats were irradiated at a ground-based charged particle accelerator facility with high energy ion beams broadly representative of GCRs: protons, silicon and iron. Irradiation was given either as a single ion beam or as a combination of three ion beams. For the doses used, the single ion beam studies did not show any significant changes in the known cardiac risk factors and no evidence of cardiovascular disease could be demonstrated. In the three ion beam study, the total cholesterol levels in the circulation increased modestly over the 270 day follow up period, and inflammatory cytokines were also increased, transiently, 30 days after irradiation. Perivascular cardiac collagen content, systolic blood pressure and the number of macrophages found in the kidney and in the heart were each increased 270 days after irradiation with 1.5 Gy of the three ion beam grouping. These findings provide evidence for a cardiac vascular pathology and indicate a possible threshold dose for perivascular cardiac fibrosis and increased systemic systolic blood pressure for complex radiation fields during the 9 month follow up period. The development of perivascular cardiac fibrosis and increased systemic systolic blood pressure occurred at a physical dose of the three ion beam grouping (1.5 Gy) that was much lower than that required to show similar outcomes in earlier studies with the same rat strain exposed to photons. Further studies with longer follow up periods may help determine whether humans exposed to lower, mission-relevant doses of GCRs will develop radiation-induced heart disease.

60 APPLIED LIFE SCIENCES↗

NASA NTRS2009

Identifying Galactic Cosmic Ray Origins With Super-TIGER

Super-TIGER (Super Trans-Iron Galactic Element Recorder) is a new long-duration balloon-borne instrument designed to test and clarify an emerging model of cosmic-ray origins and models for atomic processes by which nuclei are selected for acceleration. A sensitive test of the origin of cosmic rays is the measurement of ultra heavy elemental abundances (Z > or equal 30). Super-TIGER is a large-area (5 sq m) instrument designed to measure the elements in the interval 30 < or equal Z < or equal 42 with individual-element resolution and high statistical precision, and make exploratory measurements through Z = 60. It will also measure with high statistical accuracy the energy spectra of the more abundant elements in the interval 14 < or equal Z < or equal 30 at energies 0.8 < or equal E < or equal 10 GeV/nucleon. These spectra will give a sensitive test of the hypothesis that microquasars or other sources could superpose spectral features on the otherwise smooth energy spectra previously measured with less statistical accuracy. Super-TIGER builds on the heritage of the smaller TIGER, which produced the first well-resolved measurements of elemental abundances of the elements Ga-31, Ge-32, and Se-34. We present the Super-TIGER design, schedule, and progress to date, and discuss the relevance of UH measurements to cosmic-ray origins.

deNolfo, Georgia↗

DOE OSTI2025

WEST L-mode record long pulses guided by predictions using Integrated Modeling

A new record was set on the WEST Tokamak, designed to operate long duration plasmas in a tungsten (W) environment, with an injected energy of 1.15 GJ and a plasma duration 364s. Scenario development was supported by integrated modeling using the High Fidelity Plasma Simulator (HFPS), the European IMAS-coupled version of JETTO/JINTRAC, which integrates physics-driven modules into a unified framework. In particular, a reduced model for Lower-Hybrid heating and Current-Drive (LHCD) and the quasi-linear turbulent transport model TGLF are crucial for long pulses predictions up to the Last Closed Flux Surface (LCFS). Using this workflow, a 100 s reference discharge was modeled and plasma kinetic profiles and loop voltage were quantitatively well matched. In preparation for the recent long duration experiments, non-inductive current-drive actuators (I P , n e , P LHCD ) were varied to determine the operational domain going towards fully non-inductive discharges. In particular, decreasing the plasma current is shown to ease the access to such conditions, with a careful monitoring of (n e , P LHCD ) to avoid machine limitations. In addition, post-prediction experiments conducted within the investigated parameter range validated the predicted dependencies and were shown to be in quantitative agreement. Exploratory work on the use of ECCD for MHD stability purpose is also introduced.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2025

Yes, No, Maybe So: Human Factors Considerations for Fostering Calibrated Trust in Foundation Models Under Uncertainty

High-stakes analytical environments require analysts to evaluate evidence and generate conclusions to inform critical decisions often under conditions of uncertainty. Probabilistic decision-making based on incomplete or inaccurate information can reduce productivity, compromise national interests, and endanger public safety. Researchers are developing expert systems built on foundation models (FMs) to support analysts’ decision-making processes by enabling human-artificial intelligence (AI) teaming, in part through the quantification and expression of uncertainty information. As FMs continue to mature, it is imperative to correspondingly consider analysts’ needs for appropriately interpreting and using uncertainty information. However, prior research indicates that it remains unclear how analysts engage with FM-generated uncertainty information and the extent to which these interactions influence trust in, and reliance on, expert systems. We plan to review the state of the science and conduct an exploratory, qualitative study to (a) understand how properly communicated uncertainty can foster calibrated trust and appropriate reliance and (b) identify approaches for effectively conveying FM-generated uncertainty information during analytical workflows. We will administer semi-structured interviews with analysts from a specific high-stakes analytical environment to collect their current experiences with job-related uncertainty and their impressions when viewing FM-generated uncertainty information. During the interview protocol, participants will be presented with several different FM outputs and invited to discuss their thoughts and beliefs about the uncertainty information displayed. Participants may provide insights into how trust and reliance may be influenced by uncertainty. The results of this study will help us to better understand how analysts currently interpret and use uncertainty information. Our findings may inform human factors recommendations for effectively conveying uncertainty information to foster calibrated trust in, and appropriate reliance on, expert systems. Interaction designers and FM developers can use this knowledge to enhance human-AI teaming and ensure the responsible deployment of FM-based expert systems in analytical workflows.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1990

Low-speed wind tunnel investigation of the static stability and control characteristics of an advanced turboprop configuration with the propellers placed over the tail

An exploratory wind tunnel investigation was performed in the 30 x 60 foot wind tunnel to determine the low speed static stability and control characteristics into the deep stall regime of an advanced turboprop aircraft with the propellers located over the horizontal tail. By this arrangement, the horizontal tail could potentially provide acoustic shielding to reduce the high community noise caused by the propeller blades. The current configuration was a generic turboprop model equipped with 1 foot diameter single rotating eight bladed propellers that were designed for efficient cruise operation at a Mach number of 0.8. The data presented is static force data. The effects of power on the configuration characteristics were generally favorable. An arrangement with the propellers rotating with the outboard blades moving down was found to have significantly higher installed thrust than an arrangement with the propellers rotating with the inboard blades moving down. The primary unfavorable effect was a large pitch trim change which occurred with power, but the trim change could be minimized with a proper configuration design.

Rhodes, Graham Scott↗

NASA NTRS1991

Exploratory research for the development of a computer aided software design environment with the software technology program

Field studies were conducted by MCC to determine areas of research of mutual interest to MCC and JSC. NASA personnel from the Information Systems Directorate and research faculty from UHCL/RICIS visited MCC in Austin, Texas to examine tools and applications under development in the MCC Software Technology Program. MCC personnel presented workshops in hypermedia, design knowledge capture, and design recovery on site at JSC for ISD personnel. The following programs were installed on workstations in the Software Technology Lab, NASA/JSC: (1) GERM (Graphic Entity Relations Modeler); (2) gIBIS (Graphic Issues Based Information System); and (3) DESIRE (Design Recovery tool). These applications were made available to NASA for inspection and evaluation. Programs developed in the MCC Software Technology Program run on the SUN workstation. The programs do not require special configuration, but they will require larger than usual amounts of disk space and RAM to operate properly.

Hardwick, Charles↗

NASA NTRS2000

Towards Simulating Non-Axisymmetric Influences on Aircraft Plumes for Signature Prediction

A methodology for efficiently including three-dimensional effects on aircraft plume signature is presented. First, exploratory work on the use of passive mixing enhancement devices, namely chevrons and tabs, in IR signature reduction for external turbofan plumes is demonstrated numerically and experimentally. Such small attachments, when properly designed, cause an otherwise axisymmetric plume to have significant 3D structures, affecting signature prediction. Second, an approach for including non-axisymmetric and installation effects in plume signature prediction is discussed using unstructured methodology. Unstructured flow solvers, using advanced turbulence modeling and plume thermochemistry, facilitate the modeling of aircraft effects on plume structure that previously have been neglected due to gridding complexities. The capabilities of the CRUNCH unstructured Navier-Stokes solver for plume modeling is demonstrated for a passively mixed turbofan nozzle, a generic fighter nozzle, and a complete aircraft.

Kenzakowski, D. C.↗

NASA NTRS1992

A LEX blowing technique for post-stall lateral control of trapezoidal wings

An exploratory low-speed wind-tunnel investigation of a pneumatic technique for LEX-induced lift augmetation on a low-aspect-ratio trapezoidal wing near C sub L, MAX is reported. The technique involved lateral sheet ejection from LEX edge-slots, with emphasis on nonsymmetrical blowing to obtain incremental roll control at high angles of attack when the aileron power is declining. Preliminary experiments on a pressure instrumented semispan wing model followed by force/moment measurements on a full-span LEX-wing configuration confirmed the effectiveness of LEX blowing for lateral control improvement up to an angle of attack of 45 deg and with a momentum coefficient of less than 02.

Rao, Dhanvada M.↗

NASA NTRS2004

The Structure of Young Stellar Systems: Establishing the Initial Conditions for Planet Formation

FYO1-FY03 Origins support to the PI had been as part of an effort involving Profs. Blake, van Dishoeck and L.G. Mundy of the University of Maryland. As outlined below, the merging of BIMA+OVRO into the Combined Array for Research in Millimeter Astronomy (CARMA) and our mutual involvement in the Spitzer Legacy Science program now provides a more natural means of continuing the Caltech/Maryland collaboration. In addition, the spectroscopy/radiative transfer programs led by Profs. Blake, Hogerheijde, and van Dishoeck form a more cohesive basis for a single proposal. Students supported by our previous Origins grant have been involved in making some of the first sub-arcsecond resolution images of the morphology and chemistry of individual YSOs at OVRO and BIMA, in the analysis of IR spectra taken by ISO, and in continuing exploratory IR diffraction-limited imaging and spectroscopy at the Keck and VLT observatories. Notable scientific accomplishments in the past grant period include: 1) detecting high density and temperature hot cores in the dynamically accreting envelopes of low mass protostars that contain significant quantities of complex, prebioitc molecules, 2) imaging chemical and isotopic zonation in the outer regions of T Tauri star accretion disks, particularly fractional ionization and D/H studies, 3) acquiring and modeling the first extensive CO v = 1 approaches 0 spectroscopy survey of the terrestrial planet-forming region of circumstellar accretion disks, and 4) optimizing detailed radiative transfer modeling of the molecular and dust emission from YSO envelopes and from comets, including a new parallelized implementation.

Blake, Geoffrey A.↗

NASA NTRS1973

Thermal control subsystem design of a Saturn/Uranus atmospheric entry probe for descent missions to 20 bars.

A study of scientific probes to explore the atmospheres of Saturn and Uranus to depths of between 2 and 30 bars is summarized. The study assessed configuration tradeoffs of recommended exploratory payloads, determined the types and quantities of the thermal control devices required, and evaluated thermal structural details and viable mission alternatives. These results indicated that a vented probe design with an environmental pressurization system for the first 2.5 bars of descent would satisfy the requirements for missions to either Saturn or Uranus to depths of approximately 20 bars. Parametric atmospheric descent thermal analyses are discussed and the effect of worst-case atmospheric models and navigational arrival uncertainties on mission performance are presented.

Webb, C. M.↗