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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

A Survey for New Stars and Brown Dwarfs in the Ophiuchus Star-forming Complex

We have performed a survey for new members of the Ophiuchus cloud complex using high-precision astrometry from the second data release of Gaia, proper motions measured with multi-epoch images from the Spitzer Space Telescope, and color–magnitude diagrams constructed with photometry from various sources. Through spectroscopy of candidates selected with those data, we have identified 155 new young stars. Based on available measurements of kinematics, we classify 102, 47, and 6 of those stars as members of Ophiuchus, Upper Sco, and other populations in Sco–Cen, respectively. We have also assessed the membership of all other stars in the vicinity of Ophiuchus that have spectroscopic evidence of youth from previous studies, arriving at a catalog of 373 adopted members of the cloud complex. For those adopted members, we have compiled mid-infrared photometry from Spitzer and the Wide-field Infrared Survey Explorer and have used mid-infrared colors to identify and classify circumstellar disks. We find that 210 of the members show evidence of disks, including 48 disks that are in advanced stages of evolution. Finally, we have estimated the relative median ages of the populations near the Ophiuchus clouds and the surrounding Upper Sco association using absolute K-band magnitudes (M {sub K}) based on Gaia parallaxes. If we adopt an age 10 Myr for Upper Sco, then the relative values of M {sub K} imply median ages of ∼2 Myr for L1689 and embedded stars in L1688, 3–4 Myr for low-extinction stars near L1688, and ∼6 Myr for the group containing ρ Oph.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Faint Object Detection in Multi-Epoch Observations via Catalog Data Fusion

Astronomy in the time-domain era faces several new challenges. One of them is the efficient use of observations obtained at multiple epochs. The work presented here addresses faint object detection and describes an incremental strategy for separating real objects from artifacts in ongoing surveys. The idea is to produce low-threshold single-epoch catalogs and to accumulate information across epochs. This is in contrast to more conventional strategies based on co-added or stacked images. We adopt a Bayesian approach, addressing object detection by calculating the marginal likelihoods for hypotheses asserting that there is no object or one object in a small image patch containing at most one cataloged source at each epoch. The object-present hypothesis interprets the sources in a patch at different epochs as arising from a genuine object; the no-object hypothesis interprets candidate sources as spurious, arising from noise peaks. We study the detection probability for constant-flux objects in a Gaussian noise setting, comparing results based on single and stacked exposures to results based on a series of single-epoch catalog summaries. Our procedure amounts to generalized cross-matching: it is the product of a factor accounting for the matching of the estimated fluxes of the candidate sources and a factor accounting for the matching of their estimated directions. We find that probabilistic fusion of multi-epoch catalogs can detect sources with similar sensitivity and selectivity compared to stacking. The probabilistic cross-matching framework underlying our approach plays an important role in maintaining detection sensitivity and points toward generalizations that could accommodate variability and complex object structure.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

On the Origin of Sub-subgiant Stars. I. Demographics

Sub-subgiants are stars that are observed to be redder than normal main-sequence stars and fainter than normal subgiant (and giant) stars in an optical color–magnitude diagram (CMD). The red straggler stars, which lie redward of the red giant branch, may be related and are often grouped together with the sub-subgiants in the literature. These stars defy our standard theory of single-star evolution and are important tests for binary evolution and stellar collision models. In total, we identify 65 sub-subgiants (SSG) and red stragglers (RS) in 16 open and globular star clusters from the literature; 50 of these, including 43 sub-subgiants, pass our strict membership selection criteria (though the remaining sources may also be cluster members). In addition to their unique location on the CMD, we find that at least 58% (25/43) of sub-subgiants in this sample are X-ray sources with typical 0.5–2.5 keV luminosities of order 10{sup 30}–10{sup 31} erg s{sup −1}. Their X-ray luminosities and optical–to–X-ray flux ratios are similar to those of RS CVn active binaries. At least 65% (28/43) of the sub-subgiants in our sample are variables, 21 of which are known to be radial-velocity binaries. Typical variability periods are ≲15 days. At least 33% (14/43) of the sub-subgiants are H α emitters. These observational demographics provide strong evidence that binarity is important for sub-subgiant formation. Finally, we find that the number of sub-subgiants per unit mass increases toward lower-mass clusters, such that the open clusters in our sample have the highest specific frequencies of sub-subgiants.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

The Fermi-LAT Lightcurve Repository

The Fermi Large Area Telescope (LAT) lightcurve repository (LCR) is a publicly available, continually updated library of gamma-ray lightcurves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality lightcurves binned on timescales of 3, 7, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 yr of Fermi-LAT observations. The repository consists of lightcurves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multimessenger communities by allowing users to search LAT data quickly to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2011

Integrating Nuclear Energy to Oilfield Operations – Two Case Studies

Fossil fuel resources that require large energy inputs for extraction, such as the Canadian oil sands and the Green River oil shale resource in the western USA, could benefit from the use of nuclear power instead of power generated by natural gas combustion. This paper discusses the technical and economic aspects of integrating nuclear energy with oil sands operations and the development of oil shale resources. A high temperature gas reactor (HTGR) that produces heat in the form of high pressure steam (no electricity production) was selected as the nuclear power source for both fossil fuel resources. Both cases were based on 50,000 bbl/day output. The oil sands case was a steam-assisted, gravity-drainage (SAGD) operation located in the Canadian oil sands belt. The oil shale development was an in-situ oil shale retorting operation located in western Colorado, USA. The technical feasibility of the integrating nuclear power was assessed. The economic feasibility of each case was evaluated using a discounted cash flow, rate of return analysis. Integrating an HTGR to both the SAGD oil sands operation and the oil shale development was found to be technically feasible for both cases. In the oil sands case, integrating an HTGR eliminated natural gas combustion and associated CO2 emissions, although there were still some emissions associated with imported electrical power. In the in situ oil shale case, integrating an HTGR reduced CO2 emissions by 88% and increased natural gas production by 100%. Economic viabilities of both nuclear integrated cases were poorer than the non-nuclear-integrated cases when CO2 emissions were not taxed. However, taxing the CO2 emissions had a significant effect on the economics of the non-nuclear base cases, bringing them in line with the economics of the nuclear-integrated cases. As we move toward limiting CO2 emissions, integrating non-CO2-emitting energy sources to the development of energy-intense fossil fuel resources is becoming increasingly important. This paper attempts to reduce the barriers that have traditionally separated fossil fuel development and application of nuclear power and to promote serious discussion of ideas about hybrid energy systems.

03 NATURAL GAS↗
DOE OSTI2013

Catheter based mid-infrared reflectance and reflectance generated absorption spectroscopy

A method of characterizing conditions in a tissue, by (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-IR spectrum; (b) directing the light from the catheter to an area of tissue at a location inside a blood vessel of a subject; (c) collecting light reflected from the location and generating a reflectance spectra; and (d) comparing the reflectance spectra to a reference spectra of normal tissue, whereby a location having an increased number of absorbance peaks at said selected wavenumbers indicates a tissue inside the blood vessel containing a physiological marker for atherosclerosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Full-Scale Cask Testing and Public Acceptance of Spent Nuclear Fuel Shipments - 12254

Full-scale physical testing of spent fuel shipping casks has been proposed by the National Academy of Sciences (NAS) 2006 report on spent nuclear fuel transportation, and by the Presidential Blue Ribbon Commission (BRC) on America's Nuclear Future 2011 draft report. The U.S. Nuclear Regulatory Commission (NRC) in 2005 proposed full-scale testing of a rail cask, and considered 'regulatory limits' testing of both rail and truck casks (SRM SECY-05-0051). The recent U.S. Department of Energy (DOE) cancellation of the Yucca Mountain project, NRC evaluation of extended spent fuel storage (possibly beyond 60-120 years) before transportation, nuclear industry adoption of very large dual-purpose canisters for spent fuel storage and transport, and the deliberations of the BRC, will fundamentally change assumptions about the future spent fuel transportation system, and reopen the debate over shipping cask performance in severe accidents and acts of sabotage. This paper examines possible approaches to full-scale testing for enhancing public confidence in risk analyses, perception of risk, and acceptance of spent fuel shipments. The paper reviews the literature on public perception of spent nuclear fuel and nuclear waste transportation risks. We review and summarize opinion surveys sponsored by the State of Nevada over the past two decades, which show consistent patterns of concern among Nevada residents about health and safety impacts, and socioeconomic impacts such as reduced property values along likely transportation routes. We also review and summarize the large body of public opinion survey research on transportation concerns at regional and national levels. The paper reviews three past cask testing programs, the way in which these cask testing program results were portrayed in films and videos, and examines public and official responses to these three programs: the 1970's impact and fire testing of spent fuel truck casks at Sandia National Laboratories, the 1980's regulatory and demonstration testing of MAGNOX fuel flasks in the United Kingdom (the CEGB 'Operation Smash Hit' tests), and the 1980's regulatory drop and fire tests conducted on the TRUPACT II containers used for transuranic waste shipments to the Waste Isolation Pilot Plant in New Mexico. The primary focus of the paper is a detailed evaluation of the cask testing programs proposed by the NRC in its decision implementing staff recommendations based on the Package Performance Study, and by the State of Nevada recommendations based on previous work by Audin, Resnikoff, Dilger, Halstead, and Greiner. The NRC approach is based on demonstration impact testing (locomotive strike) of a large rail cask, either the TAD cask proposed by DOE for spent fuel shipments to Yucca Mountain, or a similar currently licensed dual-purpose cask. The NRC program might also be expanded to include fire testing of a legal-weight truck cask. The Nevada approach calls for a minimum of two tests: regulatory testing (impact, fire, puncture, immersion) of a rail cask, and extra-regulatory fire testing of a legal-weight truck cask, based on the cask performance modeling work by Greiner. The paper concludes with a discussion of key procedural elements - test costs and funding sources, development of testing protocols, selection of testing facilities, and test peer review - and various methods of communicating the test results to a broad range of stakeholder audiences. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Selection biases in empirical p(z) methods for weak lensing

To measure the mass of foreground objects with weak gravitational lensing, one needs to estimate the redshift distribution of lensed background sources. This is commonly done in an empirical fashion, i.e. with a reference sample of galaxies of known spectroscopic redshift, matched to the source population. In this paper, we develop a simple decision tree framework that, under the ideal conditions of a large, purely magnitude-limited reference sample, allows an unbiased recovery of the source redshift probability density function p(z), as a function of magnitude and colour. We use this framework to quantify biases in empirically estimated p(z) caused by selection effects present in realistic reference and weak lensing source catalogues, namely (1) complex selection of reference objects by the targeting strategy and success rate of existing spectroscopic surveys and (2) selection of background sources by the success of object detection and shape measurement at low signal to noise. For intermediate-to-high redshift clusters, and for depths and filter combinations appropriate for ongoing lensing surveys, we find that (1) spectroscopic selection can cause biases above the 10 per cent level, which can be reduced to ≈5 per cent by optimal lensing weighting, while (2) selection effects in the shape catalogue bias mass estimates at or below the 2 per cent level. Finally, this illustrates the importance of completeness of the reference catalogues for empirical redshift estimation.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Controlled photo-discharge of dust in a complex plasma

One of the limitations in studying dusty plasmas is that many of the important properties of the dust (like the charge) are directly coupled to the surrounding plasma conditions rather than being determined independently. The application of high-intensity ultraviolet (UV) sources to generate discharging photoelectric currents may provide an avenue for developing methods of controlling dust charge. Careful selection of the parameters of the UV source and dust material may even allow for this to be accomplished with minimal perturbation of the background plasma. The Auburn Magnetized Plasma Research Laboratory (MPRL) has developed a ‘proof-of-concept’ experiment for this controlled photo-discharging of dust; a high-intensity, near-UV source was used to produce large changes in the equilibrium positions of lanthanum hexaboride ( $\textrm {LaB}_6$ ) particles suspended in an argon DC glow discharge with negligible changes in the potential, density and temperature profiles of the background plasma. The shifts in equilibrium position of the dust are consistent with a reduction in dust charge. Video analysis is used to quantify the changes in position, velocity and acceleration of a test particle under the influence of the UV and Langmuir probes are used to measure the effects on the plasma.

Physics↗
DOE OSTI2024

Representative Period Selection for Robust Capacity Expansion Planning in Low-carbon Grids

With the increasing urgency to decarbonize power systems, while mitigating extreme events, capacity expansion models can play a vital role in reliably planning the expansion of power systems and facilitating the integration of renewable energy sources. Optimizing capacity expansion generally involves selecting surrogate representative days from forecasts of load and the generation profiles of variable renewable energy resources. To properly select those representative days, we propose a novel input-based approach in combination with the k-means clustering algorithm that utilize three unique operational inputs: load shedding, renewable curtailment, and transmission congestion. The proposed method allows for more robust and cost-effective capacity planning. The method is validated using a capacity expansion model and a production cost model based on California Independent System Operator (CAISO)'s decarbonization goals, and results in reduced costs and drastically lower load shedding.

Anderson, Osten P.↗
DOE OSTI2012

VERITAS OBSERVATIONS OF SIX BRIGHT, HARD-SPECTRUM FERMI-LAT BLAZARS

We report on VERITAS very high energy (VHE; E {>=} 100 GeV) observations of six blazars selected from the Fermi Large Area Telescope First Source Catalog (1FGL). The gamma-ray emission from 1FGL sources was extrapolated up to the VHE band, taking gamma-ray absorption by the extragalactic background light into account. This allowed the selection of six bright, hard-spectrum blazars that were good candidate TeV emitters. Spectroscopic redshift measurements were attempted with the Keck Telescope for the targets without Sloan Digital Sky Survey spectroscopic data. No VHE emission is detected during the observations of the six sources described here. Corresponding TeV upper limits are presented, along with contemporaneous Fermi observations and non-concurrent Swift UVOT and X-Ray Telescope data. The blazar broadband spectral energy distributions (SEDs) are assembled and modeled with a single-zone synchrotron self-Compton model. The SED built for each of the six blazars shows a synchrotron peak bordering between the intermediate- and high-spectrum-peak classifications, with four of the six resulting in particle-dominated emission regions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Nonfuel antineutrino contributions in the ORNL High Flux Isotope Reactor (HFIR)

Reactor neutrino experiments have seen major improvements in precision in recent years. With the experimental uncertainties becoming lower than those from theory, carefully considering all sources of $\bar{ν}$ e is important when making theoretical predictions. One source of νe that is often neglected arises from the irradiation of the nonfuel materials in reactors. The $\bar{ν}$ e rates and energies from these sources vary widely based on the reactor type, configuration, and sampling stage during the reactor cycle and have to be carefully considered for each experiment independently. In this article, we present a formalism for selecting the possible $\bar{ν}$ e sources arising from the neutron captures on reactor and target materials. We apply this formalism to the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, the $\bar{ν}$ e source for the the Precision Reactor Oscillation and Spectrum Measurement (PROSPECT) experiment. Overall, we observe that the nonfuel $\bar{ν}$ e contributions from HFIR to PROSPECT amount to 1% above the inverse beta decay threshold with a maximum contribution of 9% in the 1.8–2.0 MeV range. Nonfuel contributions can be particularly high for research reactors like HFIR because of the choice of structural and reflector material in addition to the intentional irradiation of target material for isotope production. We show that typical commercial pressurized water reactors fueled with low-enriched uranium will have significantly smaller nonfuel $\bar{ν}$ e contribution.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Moderate pH changes alter the fluxes, selectivities and limiting currents in ion transport through polyelectrolyte multilayers deposited on membranes

Layer-by-layer (LBL) polyelectrolyte coatings on membranes are attractive for their high selectivities between monovalent and divalent ions. However, deposition of poly(4-styrenesulfonate) (PSS)/protonated poly(allylamine) (PAH) films on ion-exchange membranes leads to low ion fluxes that restrict productivity or current efficiency. This study shows that increasing the solution pH from 6.5 to 8.3 enhances cation fluxes and limiting currents through (PAH/PSS) 5 PAH-coated cation-exchange membranes while still achieving order of magnitude selectivity increases compared to bare membranes. In Donnan dialysis through (PAH/PSS) 5 PAH-coated Nafion, at pH 8.3 the K + /Mg 2+ selectivity is 100, and the K + flux is 22 times that at pH 6.5. Moreover, at the higher pH the electrodialysis limiting current through these membranes increases ~5-fold. This enables electrodialysis separation of K + and Mg 2+ with a current efficiency around 0.75, a selectivity of 18, and 50% K + recovery from the source phase. Transmembrane potential measurements and increases in Cl - /SO 4 2- selectivities (from 9.5 at pH 6.5 to ~70 at pH 8.3) for porous alumina membranes coated with (PSS/PAH) 5 PSS films suggest that the coating becomes cation-permselective at higher pH. Increased cation transference numbers in polyelectrolyte coatings likely lead to the enhanced limiting currents for coated Nafion at higher pH. Lastly, (PAH/PSS) 5 PAH-coated Nafion shows a Li + /Mg 2+ Donnan dialysis selectivity >700 at neutral pH and a selectivity of 10 at pH 8.3. However, the Li + flux is 6 times greater at pH 8.3, which might make operation at the higher pH desirable.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Economical and Environmentally Benign Extraction of Rare Earth Elements (REES) from Coal & Coal Byproducts

This final report provides a complete summary of the activities, results, analytical discussion, and overall evaluation of the project titled “Economical and Environmentally Benign Extraction of Rare Earth Elements (REES) from Coal & Coal Byproducts” under DOE Award Number DE-FE-0027155 that started in March 2016 and ended December 2017. Fly ash was selected as the coal-byproduct source material due to fact that it is readily available with no need for extensive methods to obtain the material, it is produced in large quantities (>50 million tons per year) and had REE concentrations similar to other coal-byproducts. The selected fly ash used throughout this project was from the Mill Creek power generating facility operated by Louisville Gas and Electric located in Louisville, KY and was subjected to a variety of physical and chemical characterization tests. Results from fusion extractions showed that the selected fly-ash had a TREE+Y concentration of 480 ppm with critical REEs concentration of 200 ppm. The fly ash had an outlook ratio of 1.25 and an estimated value of $16-$18 worth of salable REEs per 1-tonne of fly ash. Additional characterizations by optical evaluation, QEMSCAN, XRD, size fractionation, and SEM analysis showed the fly ash consisted of small glassy spherules with a size range between 1 to 110 µm (ave. diam. of 13 um), was heterogeneous in chemical composition (main crystalline phases: aluminum oxides and iron oxides) and was primarily an amorphous material (75 to 80%). A simple stepped approach was completed to estimate the total REE resource quantity. The approach included REE characterization of the representative samples, evaluation of fly-ash availability, and final determination estimated resource availability with regards to REE grade on a regional and national scale. This data represents the best available information and is based upon the assumptions that the power generating facility where the fly-ash was obtained will use the same coal sources (actual mines were identified), the coal materials will have relatively consistent REE concentrations, and the REE extraction process developed during this project can achieve 42% REE recovery (validated and confirmed). Calculations indicated that the estimated REE resource is approximately 175,000 tonnes with a current estimated value of $3,330MM. The proposed REE extraction and production process developed during this project used four fundamental steps; 1) fly-ash pretreatment to enhance REE extraction, 2) REE extraction by acid digestion, 3) REE separation/concentration by carbon adsorption and column chromatography, and 4) REE oxide production. Secondary processing steps to manage process residuals and additional processing techniques to produce value-added products were incorporated into the process during the project. These secondary steps were not only necessary to manage residuals, but also provided additional revenue streams that offset operational and capital expenditures. The process produces one value product stream (production of zeolite Na-P1), a solids waste stream, and one liquid stream that met RCRA discharge requirements. Based upon final design criteria and operational parameters, the proposed system could produce approximately 200 grams of REOs from 1-tonne of fly-ash, thereby representing a TREE+Y recovery of 42% (project target of > 25%). A detailed economic model was developed to evaluate both CAPEX and OPEX estimates for systems with varying capacities between 100 kg to 200 tonnes of fly ash processed per day. Using a standard system capacity of 10 tonne/day system, capital costs were estimated at $88/kg fly ash while operating costs were estimated at approximately $450/kg fly ash. This operating cost estimate includes a revenue of $495/tonne of fly ash processed from the value-added product produced from the system (zeolite Na-P1). Although operating cost savings due to zeolite production were significant, the capital + operating cost for a 10 tonne system was more expensive than the total dollar value of REEs present in the fly ash material. Specifically, the estimated cost per 1-tonne of fly ash treated is approximately $540 while the estimated value of REEs in the fly ash is $18-$20/tonne. This is an excessive difference showing that the proposed process is not economically feasible strictly on the basis of REE revenue compared to extraction costs. Although the current proposed system does not produce sufficient quantities of REEs or additional revenue sources to offset operational and capital costs, supplementary factors including US strategic concerns, commercial demands, and defense department requirements must be factored. At this time, the process developed during this project provides foundational information for future development of simple processes that require low capital investment and one that will extract a valuable quality and quantity of REE oxides from industrial waste.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2012

THE EVOLUTION AND ENVIRONMENTS OF X-RAY EMITTING ACTIVE GALACTIC NUCLEI IN HIGH-REDSHIFT LARGE-SCALE STRUCTURES

We use deep Chandra imaging and an extensive optical spectroscopy campaign on the Keck 10 m telescopes to study the properties of X-ray point sources in two isolated X-ray-selected clusters, two superclusters, and one 'supergroup' at redshifts of z {approx} 0.7-0.9. We first study X-ray point sources using the statistical measure of cumulative source counts, finding that the measured overdensities are consistent with previous results, but we recommend caution in overestimating the precision of the technique. Optical spectroscopy of objects matched to X-ray point sources confirms a total of 27 active galactic nuclei (AGNs) within 5 structures, and we find that their host galaxies tend to be located away from dense cluster cores. More than 36% of the host galaxies are located in the 'green valley' on a color-magnitude diagram, which suggests they are a transitional population. Based on analysis of [O II] and H{delta} line strengths, the average spectral properties of the AGN host galaxies in all structures indicate either ongoing star formation or a starburst within {approx}1 Gyr, and that the host galaxies are younger than the average galaxy in the parent population. These results indicate a clear connection between starburst and nuclear activity. We use composite spectra of the spectroscopically confirmed members in each structure (cluster, supergroup, or supercluster) to separate them based on a measure of the overall evolutionary state of their constituent galaxies. We define structures as having more evolved populations if their average galaxy has lower EW([O II]) and EW(H{delta}). The AGNs in the more evolved structures have lower rest-frame 0.5-8 keV X-ray luminosities (all below 10{sup 43.3} erg s{sup -1}) and longer times since a starburst than those in the unevolved structures, suggesting that the peak of both star formation and AGN activity has occurred at earlier times. With the wide range of evolutionary states and time frames in the structures, we use our results to analyze the evolution of X-ray AGNs and evaluate potential triggering mechanisms.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics

Here, ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these strengths, ultrafast x-rays have been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant x-ray Raman scattering (AS-RXRS) performed at the LCLS, and ab initio theory we establish background free excited state selectivity in addition to the elemental, chemical, orbital and magnetic selectivity of x-rays. This unparalleled selectivity extracts low concentration excited state species along the pathway of photo induced ligand exchange of Fe(CO)5 in ethanol. Conceptually a full theoretical treatment of all accessible insights to excited state dynamics with AS-RXRS with transform-limited x-ray pulses is given—which will be covered experimentally by upcoming transform-limited x-ray sources.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Planck intermediate results: LIV. The Planck multi-frequency catalogue of non-thermal sources$^\star$

This paper presents the Planck Multi-frequency Catalogue of Non-thermal (i.e. synchrotron-dominated) Sources (PCNT) observed between 30 and 857 GHz by the ESA Planck mission. This catalogue was constructed by selecting objects detected in the full mission all-sky temperature maps at 30 and 143 GHz, with a signal-to-noise ratio (S/N)> 3 in at least one of the two channels after filtering with a particular Mexican hat wavelet. As a result, 29 400 source candidates were selected. Then, a multi-frequency analysis was performed using the Matrix Filters methodology at the position of these objects, and flux densities and errors were calculated for all of them in the nine Planck channels. This catalogue was built using a different methodology than the one adopted for the Planck Catalogue of Compact Sources (PCCS) and the Second Planck Catalogue of Compact Sources (PCCS2), although the initial detection was done with the same pipeline that was used to produce them. The present catalogue is the first unbiased, full-sky catalogue of synchrotron-dominated sources published at millimetre and submillimetre wavelengths and constitutes a powerful database for statistical studies of non-thermal extragalactic sources, whose emission is dominated by the central active galactic nucleus. Together with the full multi-frequency catalogue, we also define the Bright Planck Multi-frequency Catalogue of Non-thermal Sources (PCNTb), where only those objects with a S/N > 4 at both 30 and 143 GHz were selected. In this catalogue 1146 compact sources are detected outside the adopted Planck GAL070 mask; thus, these sources constitute a highly reliable sample of extragalactic radio sources. We also flag the high-significance subsample (PCNThs), a subset of 151 sources that are detected with S/N > 4 in all nine Planck channels, 75 of which are found outside the Planck mask adopted here. The remaining 76 sources inside the Galactic mask are very likely Galactic objects.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Complex Sources and Impacts on Remediation and Monitoring Approaches - 19058

Remedy selection, implementation, and coordination with tank farm activities for adjacent waste sites need to be facilitated by a technically defensible description of sources and their relative strength and temporal contributions to groundwater contamination. Detailed data describing contaminant source releases are typically not available, so source locations are highly uncertain. Furthermore, data on sources and model parameters are not readily available through direct measurements. Instead, source data are often derived by extrapolation from a few direct and/or indirect measurements, while model parameters are commonly estimated using inverse modeling or calibration methods. Because the conceptual model of sources will influence the mass and timing of the flux of contaminants to groundwater, uncertainty in the source terms should be considered. Even though a best-fit model can often be identified, it may not be the best representation of the sources given the sparse, uncertain nature of the data used for estimating source terms. To support future feasibility studies, a systematic approach is needed for identifying remediation and monitoring activities appropriate under conditions of uncertainty. In this study, an integrated assessment of alternative conceptual model elements has been examined using the B-Complex site in the Hanford Central Plateau to demonstrate how multiple sources in a waste management complex can be described to identify their relative contributions to groundwater. The heterogeneous structure of the system is modeled based on available field information on the lithological data for both the vadose zone and aquifer. The approach includes a simulation assessment and linkages to site data, with an uncertainty analysis applied to evaluate the effects of source term uncertainty on contaminant mass flux to groundwater. An integrated assessment of alternative conceptual model elements was evaluated to identify how parameter uncertainty impacts both temporal and spatial uncertainties associated with vadose zone source terms. Modeling scenarios identify important characteristics of remediation target zones to provide context for how surface barriers, in situ remedies, and water-table treatment zones can be designed to account for source dynamics. Ramifications for remediation and monitoring are discussed within the context of the source term uncertainty. The described approach facilitates systematically addressing alternative conceptual model questions in relation to remediation and monitoring and supports the remedial investigation/ feasibility study process and the remediation strategy development for the Hanford Central Plateau. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗