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NASA NTRS1995

ROSAT observation program

In this annual progress report (November 1, 1993 to October 31, 1994), the geminga pulsar was observed by the ROSAT PSPC for 37,000 s in September 1993, in order to make a more detailed study than was previously possible of the pulse profile and two-component spectrum, and to do phase-resolved spectroscopy. This exposure was 2.5 times longer than the original discovery observation. In addition, a shorter 4,000 s exposure was made in October 1992, simultaneously with a GRO observation of Geminga, in order to verify the absolute phasing of the X-ray and gamma-ray peaks. We verified that the spectrum can be described as the sum of two black bodies, whose temperatures are 6 x 10(exp 5) K and 3 - 4 x 10(exp 6) K, with the latter covering 3 x 10(exp -5) the area of the former. The pulse profiles indicate that the intensity of the two emitting regions peak is approximately 90 deg out of phase in rotation, but that the temperatures are otherwise independent of phase. An improved estimate of the distance can be made from the cooler (larger) blackbody component, yielding d = 440 +/- 120 pc. Another program of this report was to obtain PSPC spectra of an important class of Seyfert galaxies which have narrow lines and stron permitted Fe II emission. Sometines called I Zw 1 objects, or narrow-line Seyfert 1s, they are crucial to our understanding of Seyfert classification and models of Seyfert unification. We observed four new objects and, in addition, obtained data on 17 more from the ROSAT archive. A third program combined PSPC and HRI observations of selected Seyfert galaxies which have unusual and variable spectra. The purpose was to disentangle diffuse X-ray emission from the nuclear source, in order to properly interpret the soft X-ray spectral shapes in terms of partial covering and/or warm-absorber models. The targets of the program are NGC 3516, NGC 3227, and NGC 7314. So far, we have only performed a dtailed analysis on NGC 3516. The fourth program of this report is the NGC 1672, the second brightest Seyfert galaxy and one or the original 'composite' Seyfert/starburst galaxies which have evidence for both Seyfert activity and H II regions in their optical spectra. It is one of the lowest luminosity Seyfert 2 galaxies that can be studied in detail.

Halpern, Jules P.↗
NASA NTRS2014

Data Processing and Experimental Design for Micrometeorite Impacts in Small Bodies

Comets and asteroids have been altered from their original "pristine" state by impacts occurring throughout their 4.5 billion year lives: [1]. Proof of shock deformation has been detected in the crystal structure of several Stardust samples from Comet Wild 2 [2, 3]. Analyses indicated that the planar dislocations in the crystal structure of the minerals had been imparted by impacts sustained during their lives, and not due to the aerogel capture process. Distortions to crystal structure also affect the ideal absorption spectra in the infrared, and [4], thus providing indirect evidence of its impact history and a means of remotely investigating the impact history of small bodies through comparing laboratory spectra with spectra observed by telescopes or spacecraft. -The effects of impacts propagating shock waves through minerals were investigated through laboratory impact experiments. Utilizing NASA Johnson Space Center's Experimental Impact Laboratory, projectiles were fired from the vertical gun at velocities ranging from 2.0 to 2.8 km/sec, projected impact velocities between Kuiper Belt Objects. Two types of projectiles were used, including spherical alumina ceramic, whose density mimics that of rock, and cylinders made from the same material that they impacted. The target materials chosen for testing included: OLIVINES forsterite (Mg2SiO4) and fayalite, Fe2SiO4); PYROXENES enstatite (Mg2Si2O6) and diopside (MgCaSi2O6); and CARBONATES magnesite (MgCO3) and siderite (FeCO3). Targets were impacted at either 25 C or cooled to -20 C to examine the effects of temperature, if any, on lattice distortions during the shock propagation. As comets and asteroids can undergo a wide range of temperatures in their orbital lifetimes, the effect of temperature on the equation of state of minerals being shocked needs to be examined for interpreting the results of these experiments. The porosity of the target mineral is varied by either grinding it into a powder/granular texture or as whole mineral rocks to investigate the differences in shock propagation when voids are present. By varying velocity, ambient temperature, and porosity, we can investigate different variables affecting impacts in the solar system. -Data indicates that there is a non-linear relationship between peak shock pressure and the variation in infrared spectral absorbances by the distorted crystal structure. The maximum variability occurs around 37 GPa in enstatite and forsterite. The particle size distribution of the impacted material similarly changes with velocity/peak shock pressure. -The experiments described above are designed to measure the near- to mid-IR effects from these changes to the mineral structure. See Lederer et al., this meeting for additional experimental results.

Jensen, E.↗
DOE OSTI2020

Exoplanets in the Antarctic Sky. IV. Dual-band Photometry of Variables Found by the CSTAR-II Commissioning Survey at the North Sky

From the experiences learned in three decades of exoplanet search, wide-field transit surveys have proven to be one of the most effective ways to detect exoplanets. Wide field of view, however, suffers from high false-positive rates caused by blended eclipsing binaries. The chromaticity in eclipse depth is an effective feature to distinguish low-depth eclipsing binaries from transiting exoplanets, making multiple-band photometry follow-up advantageous before a target is passed onto more expensive spectroscopic follow-up. Moreover, a multiple-band photometric survey is itself a powerful method to find and vet planetary candidates and narrow down the candidate list of high-priority targets. In this work, we report the first results of a dual-band (Sloan-g and -i) wide-field photometry survey—the Chinese Small Telescope ARray II (CSTAR-II), an updated version of the original CSTAR. As a key component of the Chinese Exoplanet Searching Program from Antarctica, CSTAR-II has been tested thoroughly at a remote arctic site near Mohe during the winter of 2014. In total, 13,531 light curves with the best overall photometric precision of ∼3 mmag were extracted from 7721 stars in the Sloan-g and -i bands. Using a robust method, we have detected 63 variables, of which 48 are newly discovered. The dual-band photometric results as well as the stellar properties of the detected sources are provided in this work.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2013

Improved Understanding of the Modeled QBO Using MLS Observations and MERRA Reanalysis

The Quasi-Biennial Oscillation (QBO) dominates the variability of the tropical stratosphere on interannual time scales. The QBO has been shown to extend its influence into the chemical composition of this region through dynamical mechanisms. We have started our analysis using the realistic QBO internally generated by the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 33 years. We will show targeted comparisons with observations from NASAs Aura satellite Microwave Limb Sounder (MLS) and the Modern Era Retrospective-Analysis for Research and Applications (MERRA) reanalysis to provide insight into the simulation of the primary and secondary circulations associated with the QBO. Using frequency spectrum analysis and multiple linear regression we can illuminate the resulting circulations and deduce the strengths and weaknesses in their modeled representation. Inclusion of the QBO in our simulation improves the representation of the subtropical barriers and overall tropical variability. The QBO impact on tropical upwelling is important to quantify when calculating trends in sub-decadal scale datasets.

MERRA↗
DOE OSTI2015

Consistent evaluation of GOSAT, SCIAMACHY, carbontracker, and MACC through comparisons to TCCON

Consistent validation of satellite CO 2 estimates is a prerequisite for using multiple satellite CO 2 measurements for joint flux inversion, and for establishing an accurate long-term atmospheric CO 2 data record. We focus on validating model and satellite observation attributes that impact flux estimates and CO 2 assimilation, including accurate error estimates, correlated and random errors, overall biases, biases by season and latitude, the impact of coincidence criteria, validation of seasonal cycle phase and amplitude, yearly growth, and daily variability. We evaluate dry air mole fraction (X CO 2 ) for GOSAT (ACOS b3.5) and SCIAMACHY (BESD v2.00.08) as well as the CarbonTracker (CT2013b) simulated CO 2 mole fraction fields and the MACC CO 2 inversion system (v13.1) and compare these to TCCON observations (GGG2014). We find standard deviations of 0.9 ppm, 0.9, 1.7, and 2.1 ppm versus TCCON for CT2013b, MACC, GOSAT, and SCIAMACHY, respectively, with the single target errors 1.9 and 0.9 times the predicted errors for GOSAT and SCIAMACHY, respectively. When satellite data are averaged and interpreted according to error 2 = a 2 + b 2 / n (where n are the number of observations averaged, a are the systematic (correlated) errors, and b are the random (uncorrelated) errors), we find that the correlated error term a = 0.6 ppm and the uncorrelated error term b = 1.7 ppm for GOSAT and a = 1.0 ppm, b = 1.4 ppm for SCIAMACHY regional averages. Biases at individual stations have year-to-year variability of ~ 0.3 ppm, with biases larger than the TCCON predicted bias uncertainty of 0.4 ppm at many stations. Using fitting software, we find that GOSAT underpredicts the seasonal cycle amplitude in the Northern Hemisphere (NH) between 46–53° N. In the Southern Hemisphere (SH), CT2013b underestimates the seasonal cycle amplitude. Biases are calculated for 3-month intervals and indicate the months that contribute to the observed amplitude differences. The seasonal cycle phase indicates whether a dataset or model lags another dataset in time. We calculate this at a subset of stations where there is adequate satellite data, and find that the GOSAT retrieved phase improves substantially over the prior and the SCIAMACHY retrieved phase improves substantially for 2 of 7 sites. The models reproduce the measured seasonal cycle phase well except for at Lauder125 (CT2013b), Darwin (MACC), and Izana (+ 10 days, CT2013b), as for Bremen and Four Corners, which are highly influenced by local effects. We compare the variability within one day between TCCON and models in JJA; there is correlation between 0.2 and 0.8 in the NH, with models showing 10–100 % the variability of TCCON at different stations (except Bremen and Four Corners which have no variability compared to TCCON) and CT2013b showing more variability than MACC. This paper highlights findings that provide inputs to estimate flux errors in model assimilations, and places where models and satellites need further investigation, e.g. the SH for models and 45–67° N for GOSAT

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6

Projections of future climate change play a fundamental role in improving understanding of the climate system as well as characterizing societal risks and response options. The Scenario Model Intercomparison Project (ScenarioMIP) is the primary activity within Phase 6 of the Coupled Model Intercomparison Project (CMIP6) that will provide multi-model climate projections based on alternative scenarios of future emissions and land use changes produced with integrated assessment models. Here, we describe ScenarioMIP's objectives, experimental design, and its relation to other activities within CMIP6. The ScenarioMIP design is one component of a larger scenario process that aims to facilitate a wide range of integrated studies across the climate science, integrated assessment modeling, and impacts, adaptation, and vulnerability communities, and will form an important part of the evidence base in the forthcoming Intergovernmental Panel on Climate Change (IPCC) assessments. Furthermore, it will provide the basis for investigating a number of targeted science and policy questions that are especially relevant to scenario-based analysis, including the role of specific forcings such as land use and aerosols, the effect of a peak and decline in forcing, the consequences of scenarios that limit warming to below 2°C, the relative contributions to uncertainty from scenarios, climate models, and internal variability, and long-term climate system outcomes beyond the 21st century. In order to serve this wide range of scientific communities and address these questions, a design has been identified consisting of eight alternative 21st century scenarios plus one large initial condition ensemble and a set of long-term extensions, divided into two tiers defined by relative priority. Some of these scenarios will also provide a basis for variants planned to be run in other CMIP6-Endorsed MIPs to investigate questions related to specific forcings. Harmonized, spatially explicit emissions and land use scenarios generated with integrated assessment models will be provided to participating climate modeling groups by late 2016, with the climate model simulations run within the 2017–2018 time frame, and output from the climate model projections made available and analyses performed over the 2018–2020 period.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2002

Major Element Analysis of the Target Rocks at Meteor Crater, Arizona

We collected approximately 400 rock chips in continuous vertical profile at Meteor Crater, Arizona, representing, from bottom to top, the Coconino, Toroweap, Kaibab, and Moenkopi Formations to support ongoing compositional analyses of the impact melts and their stratigraphic source depth(s) and other studies at Meteor Crater that depend on the composition of the target rocks. These rock chips were subsequently pooled into 23 samples for compositional analysis by XRF (x ray fluorescence) methods, each sample reflecting a specific stratigraphic "subsection" approximately 5-10 in thick. We determined the modal abundance of quartz, dolomite, and calcite for the entire Kaibab Formation at vertical resolutions of 1-2 meters. The Coconino Formation composes the lower half of the crater cavity. It is an exceptionally pure sandstone. The Toroweap is only two inches thick and compositionally similar to Coconino, therefore, it is not a good compositional marker horizon. The Kaibab Formation is approximately 80 in thick. XRD (x ray diffraction) studies show that the Kaibab Formation is dominated by dolomite and quartz, albeit in highly variable proportions; calcite is a minor phase at best. The Kaibab at Meteor Crater is therefore a sandy dolomite rather than a limestone, consistent with pronounced facies changes in the Permian of SE Arizona over short vertical and horizontal distances. The Moenkopi forms the 12 in thick cap rock and has the highest Al2O3 and FeO concentrations of all target rocks. With several examples, we illustrate how this systematic compositional and modal characterization of the target ideologies may contribute to an understanding of Meteor Crater, such as the depth of its melt zone, and to impact cratering in general, such as the liberation of CO2 from shocked carbonates.

See, Thomas H.↗
DOE OSTI2023

Detecting Axion Dark Matter with Black Hole Polarimetry

The axion, as a leading dark matter candidate, is the target of many on-going and proposed experimental searches based on its coupling to photons. Ultralight axions that couple to photons can also cause polarization rotation of light which can be probed by cosmic microwave background. In this work, we show that a large axion field is inevitably developed around black holes due to the Bose-Einstein condensation of axions, enhancing the induced birefringence effects. Therefore, we propose measuring the modulation of supermassive black hole imaging polarization angles as a new probe to the axion-photon coupling of axion dark matter. The oscillating axion field around black holes induces polarization rotation on the black hole image, which is detectable and distinguishable from astrophysical effects on the polarization angle, as it exhibits distinctive temporal variability and frequency invariability. We present the range of axion-photon couplings within the axion mass range $10^{-21}-10^{-16}\text{eV}$ that can be probed by the Event Horizon Telescope. The axion parameter space probed by black hole polarimetry will expand with the improvement in sensitivity on the polarization measurement and more black hole polarimetry targets with determined black hole masses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Validation of edge turbulence codes against the TCV-X21 diverted L-mode reference case

Self-consistent full-size turbulent-transport simulations of the divertor and scrape-off-layer (SOL) of existing tokamaks have recently become feasible. This enables the direct comparison of turbulence simulations against experimental measurements. In this work, we perform a series of diverted ohmic L-mode discharges on the tokamak à configuration variable (TCV) tokamak, building a first-of-a-kind dataset for the validation of edge turbulence models. This dataset, referred to as TCV-X21, contains measurements from five diagnostic systems from the outboard midplane (OMP) to the divertor targets—giving a total of 45 one- and two-dimensional comparison observables in two toroidal magnetic field directions. The experimental dataset is used to validate three flux-driven 3D fluid-turbulence models—GBS, GRILLIX and TOKAM3X. With each model, we perform simulations of the TCV-X21 scenario, individually tuning the particle and power source rates to achieve a reasonable match of the upstream separatrix value of density and electron temperature. We find that the simulations match the experimental profiles for most observables at the OMP—both in terms of profile shape and absolute magnitude—while a comparatively poorer agreement is found towards the divertor targets. The match between simulation and experiment is seen to be sensitive to the value of the resistivity, the heat conductivities, the power injection rate and the choice of sheath boundary conditions. Additionally, despite targeting a sheath-limited regime, the discrepancy between simulations and experiment also suggests that the neutral dynamics should be included. The results of this validation show that turbulence models are able to perform simulations of existing devices and achieve reasonable agreement with experimental measurements. Where disagreement is found, the validation helps to identify how the models can be improved. By publicly releasing the experimental dataset and validation analysis, this work should help to guide and accelerate the development of predictive turbulence simulations of the edge and SOL.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

Data-Driven Distribution System Load Modeling for Quasi-Static Time-Series Simulation

This paper presents a data-driven distribution system load modeling methodology targeting quasi-static time-series (QSTS) simulation. The proposed methodology is appropriate for modeling down to the level of the customer transformer, and it has three main features: 1) both load pattern diversity and intra-second load variability are considered, 2) the load profiles can be populated for multiple nodes on a circuit in such a way that the diversity factor of the feeder can be defined and tuned, and 3) the load aggregation method can be used to populate the profiles for different nodes at various load aggregation levels. Furthermore, as the foundation of the modeling methodology, variability and diversity libraries have been established based on high-resolution load data collected on customer transformers from real utility feeders. The proposed modeling methodology has been used to build load data sets for both the IEEE 123-bus feeder model and a realistic utility feeder model. The QSTS simulation results on the two evaluation feeders have demonstrated that the load data sets established from the proposed modeling methodology can effectively capture the load impact on feeder operations. For the realistic utility feeder, the effectiveness of the proposed methodology has also been validated by comparing the voltage characteristics of the feeder with modeled loads and the voltage characteristics of realistic voltage data from the same feeder.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2019

Application of Electronics Packaging Fundamentals to Photovoltaic Interconnects and Packaging

The energy capacity of photovoltaic (PV) installations worldwide has increased significantly in the last decade, increasing the demand for rigorous investigation of the physical phenomena causing degradation and failures in PV modules. As PV reliability science develops, established methods and approaches from longer-standing industries can inform and expedite PV reliability advances. This work demonstrates how thermomechanical solder bond fatigue models derived for electronics packaging applications can be applied to both standard and emerging PV interconnect designs. This expertise cannot be directly translated to PV however, as target PV module lifetimes are significantly longer than most electronics and the modules must withstand the natural climate wherever they are deployed. Verification of analytical reliability models is then an additional challenge, due to model size, test time, and climate variability. Furthermore, unconventional materials, such as low-temperature solders, are now being integrated into PV designs, for which appropriate material models must be selected and material parameters derived. In this paper, the current state of PV interconnect research is explored, with an emphasis on the experimental and simulation approaches and models being used for this work. Recent results for standard module architectures as well as emerging interconnect schemes are discussed.

14 SOLAR ENERGY↗
DOE OSTI2015

SU-E-T-580: On the Significance of Model Based Dosimetry for Breast and Head and Neck 192Ir HDR Brachytherapy

Purpose: To assess the dosimetric and radiobiological differences between TG43-based and model-based dosimetry in the treatment planning of {sup 192}Ir HDR brachytherapy for breast and head and neck cancer. Methods: Two cohorts of 57 Accelerated Partial Breast Irradiation (APBI) and 22 head and neck (H&N) patients with oral cavity carcinoma were studied. Dosimetry for the treatment plans was performed using the TG43 algorithm of the Oncentra Brachy v4.4 treatment planning system (TPS). Corresponding Monte Carlo (MC) simulations were performed using MCNP6 with input files automatically prepared by the BrachyGuide software tool from DICOM RT plan data. TG43 and MC data were compared in terms of % dose differences, Dose Volume Histograms (DVHs) and related indices of clinical interest for the Planning Target Volume (PTV) and the Organs-At-Risk (OARs). A radiobiological analysis was also performed using the Equivalent Uniform Dose (EUD), mean survival fraction (S) and Tumor Control Probability (TCP) for the PTV, and the Normal Tissue Control Probability (N TCP) and the generalized EUD (gEUD) for the OARs. Significance testing of the observed differences performed using the Wilcoxon paired sample test. Results: Differences between TG43 and MC DVH indices, associated with the increased corresponding local % dose differences observed, were statistically significant. This is mainly attributed to their consistency however, since TG43 agrees closely with MC for the majority of DVH and radiobiological parameters in both patient cohorts. Differences varied considerably among patients only for the ipsilateral lung and ribs in the APBI cohort, with a strong correlation to target location. Conclusion: While the consistency and magnitude of differences in the majority of clinically relevant DVH indices imply that no change is needed in the treatment planning practice, individualized dosimetry improves accuracy and addresses instances of inter-patient variability observed. Research co-financed by the ESF and Greek funds through the Operational Program Education and Lifelong Learning Investing in Knowledge Society of the NSRF. Research Funding Program Aristeia. Nucletron, an Elekta company (Veenendaal, The Netherlands) is gratefully acknowledged for providing Oncentra Brachy v4.4 for research purposes.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2025

Human perturbations to mercury in global rivers

Mercury compounds are potent neurotoxins that pose threats to human health, primarily through fish consumption. Rivers, critical for drinking water and food supply, have seen rapid increases in mercury concentrations and export to coastal margins since the Industrial Revolution (~1850). However, patterns of these changes remain understudied, limiting assessments of environmental policies. Here, we develop a global model to simulate preindustrial riverine total mercury and assess human perturbations by comparing it to present-day conditions. We find that global rivers transported ~390 megagrams annually of mercury to the oceans in the preindustrial era, with spatial variability. Human activities have elevated riverine mercury budgets by two to three times in the present day. Establishing a baseline riverine mercury level, our findings reveal rapid responses of riverine mercury to human perturbations and could be used to inform targets for global riverine mercury restoration. Total riverine mercury concentrations could also be used as indicators to comprehensively understand the effectiveness of mercury pollution governance.

Science & Technology - Other Topics↗
DOE OSTI2013

A Sensitivity Analysis of Surface Biophysical, Carbon, and Climate Impacts of Tropical Deforestation Rates in CCSM4-CNDV*

The biophysical–climate and combined biophysical and carbon–climate feedbacks of tropical deforestation rates are explored through sensitivity analyses using the Community Climate System Model 4 with prognostic carbon–nitrogen and dynamic vegetation. Simulations test 5%, 2%, 1%, and 0.5% annual deforestation rates, each paired with preservation targets of 10% per tropical tree type. Perturbations are applied over pan-tropical land but analyses also explore responses over the subcontinental areas of the Amazon basin, central Africa, and Southeast Asia. Sensitivities [expressed as the change in a variable per million square kilometers (Mkm 2 ) of change in tree cover] and means of selected biophysical, carbon, and climate variables during and after deforestation are compared across rates. The most apparent effect of the rates is in hastening/postponing climate change, but otherwise results show no consistent differences across rates and vary more across subcontinents (with the Amazon basin reflecting highest sensitivities in albedo and ground temperatures, and Southeast Asia for total ecosystem carbon). Furthermore, biophysical feedbacks alone were found to have significant impact on climate over subcontinental scales. In the Amazon, ground temperature increase due to biophysical feedbacks is as much as 55%, and precipitation decrease up to 61%, of combined biophysical and carbon impacts. Replication with other models is required. While it is still unclear whether a slow but prolonged deforestation differs in impacts from one that is rapid but short, the rate can still be relevant to planning with regards to the timing of impacts.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Data, figures, animations, and scripts associated with the manuscript "Integrated Effects of Site Hydrology and Vegetation on Exchange Fluxes and Carbon Cycling at the Coastal Terrestrial Aquatic Interface"

This package contains the data, figures, animations, and scripts used in "Integrated Effects of Site Hydrology and Vegetation on Exchange Fluxes and Carbon Cycling at the Coastal Terrestrial Aquatic Interface" (Li et al., 2023). This study examines the interactions between soil, vegetation and hydrologic conditions in coastal areas, with a focus on the Chesapeake Bay region. The researchers used a mechanistic model called ATS-PFLOTRAN to explore how these interactions affect exchange process in different regions and the carbon/nitrogen cycle across the terrestrial-aquatic interface (TAI). Simulation scenarios isolate the effects of control factors and reaction constants derived from laboratory experiments. The results show a carbon cycle "hot zone" in coastal wetlands and in the transition zone between wetlands and uplands. Transpiration enhances fluxes between the surface and subsurface domains and increases dissolved oxygen in TAI. The decomposition of leaf-derived organic carbon provides an additional source of carbon for aerobic respiration and denitrification in the TAI. Microbial activity plays a key role in controlling redox conditions and their variability. This modeling study improves the understanding of complex TAI interactions and facilitates the representation of coastal ecosystems in larger-scale Earth system models.Several files can be found from this data package.1. Readme,md: This file describe the Title, Target Journal, Target submission date, Co-author, Science Questions, Hypotheses, Key words, Key message, Model and Data, Repo Structure. The user can read this file first and then go to details.2. mesh.zip: This file contains the mesh file for simulation cases. 3. Figure.zip: This file contains figures used in the manuscript . 4. animation.zip: This file contains animations used in the manuscript . 5. Data.zip: This file contains all required input data, such as concentration and flow boundaries. Also, it contains the DEM and processes results on area fraction. 6. Simulation_setup_and_results.zip: This file contains setup of cases used in the manuscript . The result files are too large, if you need that data, please contact to the Author. 7. notebooks.zip: This file contains the Jupyter notebooks for performing sensitivity analysis and other pre-process and post-process analyses.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Self-healable Copolymer Composites for Extended Service H 2 Dispensing Hoses

In this project, we designed, synthesized and fabricated using X-winder technologies precommercialized novel, self-healingable commodity copolymer fiber-reinforced composites to extend the H 2 hose service life beyond the current target of 1000 fills. These studies demonstrated that these composites are able to withstand over 25,000 damage-repair cycles, which was the main objective of the proposed project, in the temperature range of -40 to +80 °C under variable pressures. When micro-cracks are formed after about 1,000 cycles/fueling per hose in the inner composite layer, these micro-cracks self-heal, thus extending the lifetime of a prototype inner layer of the hose. These composites were tested by exposure to H 2 fuel and demonstrated the ability to recover from mechanical damage. Thermomechanical testing combined with analysis of the stress and strain fields across the cross-section of the inner layer composite hoses also identified the ring-like stresses on the edge of inner layers arising from changes of the fiber winding angle directions from +45° to -45°. The developed novel concept that self-healing commodity copolymers can be used in the development of prototype composites for the extended service of H 2 dispensing hoses will have major implications for other energy-related technologies, where the extended service life in harsh environments is expected. In this project, we optimized, validated, and demonstrated novel copolymer fiber-reinforced composites for H 2 dispensing hose applications, which can be utilized in future manufacturing using commodity materials. The estimated cost of materials (exluding labor) is in the range of < $1.0/ft.

08 HYDROGEN↗
NASA NTRS1986

Judgments of eye level in light and in darkness

Subjects judged eye level in the light and in the dark by raising and lowering themselves in a dental chair until a stationary target appeared to be at the level of their eyes. This method reduced the possibility of subjects' using visible landmarks as reference points for setting eye level during lighted trials, which may have contributed to artificially low estimates of the variability of this judgment in previous studies. Chair settings were 2.5 deg higher in the dark than in the light, and variability was approximately 66 percent greater in the dark than in the light. These results are discussed in terms of possible interactions of two separate systems, one sensitive to the orientations of visible surfaces and the other sensitive to bodily and gravitational information.

Stoper, Arnold E.↗
NASA NTRS1990

The whole earth telescope - A new astronomical instrument

A new multimirror ground-based telescope for time-series photometry of rapid variable stars, designed to minimize or eliminate gaps in the brightness record caused by the rotation of the earth, is described. A sequence of existing telescopes distributed in longitude, coordinated from a single control center, is used to measure designated target stars so long as they are in darkness. Data are returned by electronic mail to the control center, where they are analyzed in real time. This instrument is the first to provide data of continuity and quality that permit true high-resolution power spectroscopy of pulsating white dwarf stars.

Nather, R. E.↗