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All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Delayed Gamma-Ray Spectroscopy for Spent Nuclear Fuel Assay

High-energy, beta-delayed gamma-ray spectroscopy is investigated as a nondestructive assay technique for the determination of plutonium mass in spent nuclear fuel. This approach exploits the unique isotope-specific signatures contained in the delayed gamma-ray emission spectra detected following active interrogation with an external neutron source. A high fidelity modeling approach that couples radiation transport, analytical decay/depletion, and a newly developed gamma-ray emission source reconstruction code is described. Initially simulated and analyzed was a “one-pass” delayed gamma-ray assay that focused on the long-lived signatures. Also presented are the results of an independent study that investigated “pulsed mode” measurements to capture the more isotope-specific, short-lived signatures. The initial modeling results outlined in this paper suggest that delayed gamma-ray assay of spent nuclear fuel assemblies can be accomplished with a neutron generator of sufficient strength and currently available gamma-ray detectors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

A Second Opinion is Worth the Cost - 12479

This paper, 'A Second Opinion is Worth the Cost', shows how a second opinion for a Department of Energy (DOE) Project helped prepare and pass a DOE Order 413.3A 'Program and Project Management for the acquisition of Capital Assets' Office of Engineering and Construction Management (OECM) required External Independent Review (EIR) in support of the approved baseline for Critical Decision (CD) 2. The DOE project personnel were informed that the project's Total Project Cost (TPC) was going to increase from $815 million to $1.1 billion due to unforeseen problems and unexplained reasons. The DOE Project Team determined that a second opinion was needed to review and validate the TPC. Project Time and Cost, Inc. (PT and C) was requested to evaluate the cost estimate, schedule, basis of estimate (BOE), and risk management plan of the Project and to give an independent assessment of the TPC that was presented to DOE. This paper will demonstrate how breaking down a project to the work breakdown structure (WBS) level allows a project to be analyzed for potential cost increases and/or decreases, thus providing a more accurate TPC. The review Team's cost analyses of Projects identified eight primary drivers resulting in cost increases. They included: - Overstatement of the effort required to develop drawings and specifications. - Cost allocation to 'Miscellaneous' without sufficient detail or documentation. - Cost for duplicated efforts. - Vendor estimates or quotations without sufficient detail. - The practice of using the highest price quoted then adding an additional 10% mark-up. - Application of Nuclear Quality Assurance (NQA) highest level quality requirements when not required. - Allocation of operational costs to the Project Costs instead of to the Operating Expenses (OPEX). OPEX costs come from a different funding source. - DOE had not approved the activities. By using a Team approach with professionals from cost, civil, mechanical, electrical, structural and nuclear disciplines and by performing a Line by Line, WBS element by WBS element review of the Projects' CD-2 baseline package helped the DOE Project Team experience success. The second opinion that PT and C provide by conducting a Pre-EIR review of the Project baseline package and the cost review of the TPC helped the DOE Team pass the CD-2 EIR and reduced the TPC. The Line-by-Line review of the DOE Project identified opportunities to reduce the TPC from $1.1 billion to $740.8 million, thus realizing a saving of approximately $359.2 million, or roughly 32% of the original TPC. This significant cost savings underscores the cost in obtaining the second opinion. This same Line by Line review can be applied to any DOE project in the Energy Management or Weapons complex. In the case of this DOE Project a second opinion was worth the cost. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

MARIE: A Python-Based Framework for Comprehensive Fuel Recycling Modeling

One of the most pressing challenges to the continued deployment of nuclear energy systems is in the ultimate management and disposition of discharged fuel assemblies. While reprocessing and recovery of valuable materials from UNF assemblies has been considered as part of an overall strategy for minimization of the volume of reactor-based wastes to be managed, the deployment of commercial-scale reprocessing facilities presents an enormous economic challenge. The MARIE software package has been developed as a means of confronting this challenge. Representing components of a generic fuel reprocessing operation as individual physical processes, MARIE is designed as a modular framework intended to allow for analysis and cost-optimization for a hypothetical reprocessing facility while realistically accounting for the physical characteristics of the used fuel source term, such as decay heat, activity, and radiation dose (informing corresponding shielding requirements). Capabilities supported by MARIE include head-end operations such as fuel shearing, voloxidation, and dissolution; generic solvent extraction operations informed by available open-literature data; a suite of unit operations intended to represent electrochemical processing of used fuel assemblies (i.e., oxide reduction, electrorefining, and electrowinning); and finally, accounting for both costs and physical features of discharged waste streams, which can be used to inform follow-on analyses such as the feasibility of deep-borehole disposal of HLW. This paper presents an overview of the MARIE software capabilities, including how individual unit operations are implemented to enable a larger-scale optimization of a hypothetical reprocessing operation on aspects such as cost and recovery of valuable materials.

Skutnik, Steve [ORNL] (ORCID:000000016441135X)↗
DOE OSTI2013

X-RAY NUCLEAR ACTIVITY IN S{sup 4}G BARRED GALAXIES: NO LINK BETWEEN BAR STRENGTH AND CO-OCCURRENT SUPERMASSIVE BLACK HOLE FUELING

Stellar bars can lead to gas inflow toward the center of a galaxy and stimulate nuclear star formation. However, there is no compelling evidence on whether they also feed a central supermassive black hole: by measuring the fractions of barred active and inactive galaxies, previous studies have yielded conflicting results. In this paper, we aim to understand the lack of observational evidence for bar-driven active galactic nucleus (AGN) activity by studying a sample of 41 nearby (d < 35 Mpc) barred galaxies from the Spitzer Survey for Stellar Structure in Galaxies. We use Chandra observations to measure nuclear 2-10 keV X-ray luminosities and estimate Eddington ratios, together with Spitzer 3.6 μm imaging to quantify the strength of the stellar bar in two independent ways: (1) from its structure, as traced by its ellipticity and boxiness, and (2) from its gravitational torque Q{sub b} , taken as the maximum ratio of the tangential force to the mean background radial force. In this way, rather than discretizing the presence of both stellar bars and nuclear activity, we are able to account for the continuum of bar strengths and degrees of AGN activity. We find nuclear X-ray sources in 31 out of 41 galaxies with median X-ray luminosity and Eddington ratio of L{sub X} = 4.3 × 10{sup 38} erg s{sup –1} and L{sub bol}/L{sub Edd} = 6.9 × 10{sup –6}, respectively, consistent with low-luminosity AGN activity. Including upper limits for those galaxies without nuclear detections, we find no significant correlation between any of the bar strength indicators and the degree of nuclear activity, irrespective of galaxy luminosity, stellar mass, Hubble type, or bulge size. Strong bars do not favor brighter or more efficient nuclear activity, implying that at least for the low-luminosity regime, supermassive black hole fueling is not closely connected to large-scale features.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

THE COMPLEX CIRCUMNUCLEAR ENVIRONMENT OF THE BROAD-LINE RADIO GALAXY 3C 390.3 REVEALED BY CHANDRA HETG

We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory . The spectrum shows complex emission and absorption features in both the soft X-rays and Fe K band. We detect emission and absorption lines in the energy range E = 700–1000 eV associated with ionized Fe L transitions (Fe XVII–XX). An emission line at the energy of E ≃ 6.4 keV consistent with the Fe K α is also observed. Our best-fit model requires at least three different components: (i) a hot emission component likely associated with the hot interstellar medium in this elliptical galaxy with temperature kT = 0.5 ± 0.1 keV; (ii) a warm absorber with ionization parameter log ξ = 2.3 ± 0.5 erg s{sup −1} cm, column density log N {sub H} = 20.7 ± 0.1 cm{sup −2}, and outflow velocity v {sub out} < 150 km s{sup −1}; and (iii) a lowly ionized reflection component in the Fe K band likely associated with the optical broad-line region or the outer accretion disk. These evidences suggest the possibility that we are looking directly down the ionization cone of this active galaxy and that the central X-ray source only photoionizes along the unobscured cone. This is overall consistent with the angle-dependent unified picture of active galactic nuclei.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Toward a Diverse Next-Generation Energy Workforce: Teaching Artificial Photosynthesis and Electrochemistry in Elementary Schools through Active Learning

Artificial photosynthesis is a promising approach to generate commodity chemicals using abundant chemical feedstocks and renewable energy sources. Despite its importance, affordable and effective hands-on classroom activities that demonstrate artificial photosynthesis and teach key concepts, especially for primary school students, are lacking. Educating young students on this topic is a critical step in the development of the next-generation energy workforce, especially one that is diverse in race and gender. Here, we hypothesize that an effective approach to educate a broad range of young students on the topic of artificial photosynthesis is through the use of an active learning-based lesson plan that employs cheap and accessible materials. This hypothesis is confirmed by evaluating the understanding of fifth grade students with a survey before and after a lesson plan on artificial photosynthesis that uses active-learning techniques and uses safe and highly accessible materials (baking soda, tap water, plastic jars, Ni coil, alligator clips, and a solar cell) to perform solar-powered water splitting. The lesson plan and survey questions are designed to align with the educational outcomes for fifth grade classrooms in California and to address four general learning objectives: (1) Motivations of Artificial Photosynthesis, (2) Applications of Artificial Photosynthesis, (3) Inputs and Outputs of Artificial Photosynthesis, and (4) Engineering Design for Artificial Photosynthesis. The survey data demonstrate a statistically significant improvement in overall student understanding from the lesson plan. Importantly, the data show that the lesson plan presented here is effective at narrowing the performance gap between minority students and overly represented groups.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

A lower bound on the number of cosmic ray events required to measure source catalogue correlations

Recent analyses of cosmic ray arrival directions have resulted in evidence for a positive correlation with active galactic nuclei positions that has weak significance against an isotropic source distribution. In this paper, we explore the sample size needed to measure a highly statistically significant correlation to a parent source catalogue. We compare several scenarios for the directional scattering of ultra-high energy cosmic rays given our current knowledge of the galactic and intergalactic magnetic fields. We find significant correlations are possible for a sample of >1000 cosmic ray protons with energies above 60 EeV.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Cumulative Impact Evaluation Technical Approach Document

This document presents the technical approach for developing a set of tools to perform a cumulative impact evaluation (CIE) on the effects of cleanup decisions regarding groundwater quality in the Hanford Site Central Plateau. Due to the complexity and large number of waste sites in noncontiguous source operable units (OUs), the computational tools used for the CIE must be capable of representing a range of site conditions and source terms in the vadose zone while also efficiently computing the impact that cleanup decisions have on the underlying aquifer. These tools will support remedial and closure decisions across the Central Plateau by providing cumulative information, but without replacing or displacing any part of those decision processes. The objective of this document is to describe the major components required for the CIE, the approach for developing these tools, and the plan for implementation. The Central Plateau has more than 1,300 waste sites, active and inactive burial grounds, and active and inactive waste processing facilities that are regulated under a combination of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA); the Resource Conservation and Recovery Act of 1976 (RCRA); and other waste disposal regulatory frameworks. Figure 1-1 shows the source OUs on the Central Plateau and illustrates the geographical intermixing of sites within different source OUs. Groundwater OUs have several overlying source OUs, and actions taken within source OUs may affect groundwater across the entire Central Plateau. Waste site proximity between and within source OUs has resulted in contaminants commingling in the vadose and saturated zones in complex ways (Figure 1-2). Plume commingling requires cleanup decisions to be evaluated considering the surrounding waste sites and existing groundwater contamination, therefore demonstrating the need to evaluate cumulative impacts from the vadose zone to groundwater. Soil (vadose zone) and groundwater (saturated zone) contamination across the Central Plateau is undergoing investigation and remediation, and decisions need to be made regarding how to most efficiently disposition and remediate sites. Because contaminants intermingle among the OUs, decisions should be evaluated considering the context of the surrounding sites and facilities and not in isolation. Thus, the CIE of Central Plateau groundwater contamination should consider the integrated effects of numerous contaminant sources and prospective remedies. For this CIE, cumulative impacts of an action (e.g., groundwater remediation or placement of an evapotranspiration barrier over a waste site) will be viewed as the total effects on groundwater from that action, considering all other activities or likely future activities for source or groundwater OUs.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Exploratory study of atmospheric methane enhancements derived from natural gas use in the Houston urban area

Here, the extensive use of natural gas (NG) in urban areas for heating, cooking and as a vehicular fuel is associated with potentially significant emissions of methane (CH 4 ) to the atmosphere. Methane, a potent greenhouse gas that influences the chemistry of the atmosphere, can be emitted from different sources including leakage from NG infrastructure, transportation activities, end-use uncombusted NG, landfills and livestock. Although significant CH 4 leakage associated with aging local NG distribution systems in the U.S. has been reported, further investigation is required to study the role of this infrastructure component and other NG-related sources in atmospheric CH 4 enhancements in urban centers. In this study, neighborhood-scale mobile-based monitoring of potential CH 4 emissions associated with NG in the Greater Houston area (GHA) is reported. A novel dual-gas 3.337 μm interband cascade laser-based sensor system was developed and mobile-mode deployed for simultaneous CH 4 and ethane (C 2 H 6 ) monitoring during a period of over 14 days, corresponding to ~ 90 hours of effective data collection during summer 2016. The sampling campaign covered ~ 250 road miles and was primarily concentrated on eight residential zones with distinct infrastructure age and NG usage levels. A moderate number of elevated CH 4 concentration events (37 episodes) with mixing ratios not exceeding 3.60 ppmv and associated with atmospheric background enhancements below 1.21 ppmv were observed during the field campaign. Source discrimination analyses based on the covariance between CH 4 and C 2 H 6 levels indicated the predominance of thermogenic sources (e.g., NG) in the elevated CH 4 concentration episodes. The volumetric fraction of C 2 H 6 in the sources associated with the thermogenic CH 4 spikes varied between 2.7 and 5.9%, concurring with the C 2 H 6 content in NG distributed in the GHA. Isolated CH 4 peak events with significantly higher C 2 H 6 enhancements (~11 %) were observed at industrial areas and locations with high density of petroleum and gas pipelines in the GHA, indicating potential variability in Houston’s thermogenic CH 4 sources.

03 NATURAL GAS↗
DOE OSTI2015

Advancements in the application of NanoSIMS and Raman microspectroscopy to investigate the activity of microbial cells in soils

The combined approach of incubating environmental samples with stable isotope-labeled substrates followed by single-cell analyses through high-resolution secondary ion mass spectrometry (NanoSIMS) or Raman microspectroscopy provides insights into the in situ function of microorganisms. This approach has found limited application in soils presumably due to the dispersal of microbial cells in a large background of particles. We developed a pipeline for the efficient preparation of cell extracts from soils for subsequent single-cell methods by combining cell detachment with separation of cells and soil particles followed by cell concentration. The procedure was evaluated by examining its influence on cell recoveries and microbial community composition across two soils. This approach generated a cell fraction with considerably reduced soil particle load and of sufficient small size to allow single-cell analysis by NanoSIMS, as shown when detecting active N2-fixing and cellulose-responsive microorganisms via 15 N2 and 13 C-UL-cellulose incubations, respectively. The same procedure was also applicable for Raman microspectroscopic analyses of soil microorganisms, assessed via microcosm incubations with a 13 C-labeled carbon source and deuterium oxide (D2O, a general activity marker). Lastly, the described sample preparation procedure enables single-cell analysis of soil microorganisms using NanoSIMS and Raman microspectroscopy, but should also facilitate single-cell sorting and sequencing.

59 BASIC BIOLOGICAL SCIENCES↗
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 OSTI2016

The search for sterile neutrinos with SOX-Borexino

The aim of the SOX-Borexino project is to verify or falsify the existence of eV-scale sterile neutrinos. The existence of sterile neutrinos is suspected because of several anomalies, which were observed in previous experiments. A ~3.7 PBq electron antineutrino source made of {sup 144}Ce will be installed below the Borexino detector at LNGS, Italy, to search for short-baseline oscillations of active-to-sterile neutrinos within the detector volume. Source delivery and beginning of data acquisition is planned for end of 2016, preliminary results are expected already in 2017.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

CANDIDATES FOR THE YOUNG STELLAR OUTFLOWS: WATER AND METHANOL MASERS FROM YOUNG STELLAR OBJECTS

We conducted simultaneous 22 GHz water maser and 44 GHz class I methanol maser surveys of newly identified 282 H{sub 2} emission features from the 2.122 {mu}m H{sub 2} narrowband image survey in the Galactic plane (UWISH2 project) using Korean VLBI Network 21 m radio telescopes. We detected 16 and 13 new water and methanol maser sources, respectively. This result indicates that at least {approx}5% of the H{sub 2} emission features originate from young stellar objects (YSOs) that are in the right physical condition to produce the water and methanol masers. The masers are closely related to the current outflow activities in the Galactic plane. The power sources of these 23 diffused/collimated H{sub 2} emission features (six sources are detected for both masers) are likely to be intermediate- to high-mass YSOs, based on a comparison with the maser luminosities of other well-studied YSOs. Both maser velocities are mostly close to their own systemic velocities within {approx}<5 km s{sup -1}, even though water masers generally show larger variabilities in the intensity, velocity, and shape than methanol masers. We also discovered three new water maser sources with high-velocity components: {approx}25 km s{sup -1} redshifted CMHO 019, {approx}50 km s{sup -1} blueshifted CMHO 132, and {approx}120 km s{sup -1} blueshifted CMHO 182. In particular, we propose that the dominant blueshifted water maser of CHMO 182 can be a unique laboratory for the study of the high-mass young stellar jet and its acceleration.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16 N gamma radiation emitted by the activated coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16 N, the decay of 16 N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Sealed Source Security Challenges and Solutions: The Impact of Increased Commercial Disposal Access - 16557

Several recent developments have transformed the sealed source disposal landscape in the United States in ways unimaginable just a few years ago, including the initiation of operations at the first new commercial LLRW facility to open in the United States in decades; publication by the Nuclear Regulatory Commission (NRC) of revised commercial low-level radioactive waste (LLRW) disposal guidance; and the development and certification by the Department of Energy National Nuclear Security Administration (DOE/NNSA) of new transportation package designs for high-activity sources/devices. These developments will likely enable LLRW generators to dispose of risk-significant radioactive sealed sources that for decades have been without a commercial disposal pathway. However, challenges remain with regard to ensuring that these new commercial disposal pathways are effective, and that sealed source licensees take advantage of the new options in a timely manner. These challenges include costs related to both transportation and disposal that are likely much higher than most generators expected when they purchased their sources. DOE/NNSA is actively engaged with Federal, State, regional, private sector partners to address these challenges, including measures to encourage financial planning for end-of-life management of radioactive sealed sources. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

The eROSITA Final Equatorial-Depth Survey (eFEDS)

Aims. The eROSITA Final Equatorial-Depth Survey (eFEDS), executed during the performance verification phase of the Spectrum-Roentgen-Gamma (SRG)/eROSITA telescope, was completed in November 2019. One of the science goals of this survey is to demonstrate the ability of eROSITA to detect samples of clusters and groups at the final depth of the eROSITA all-sky survey. Methods. Because of the sizeable (≈26" HEW FOV average) point-spread function of eROSITA, high-redshift clusters of galaxies or compact nearby groups hosting bright active galactic nuclei (AGN) can be misclassified as point sources by the source detection algorithms. A total of 346 galaxy clusters and groups in the redshift range of 0.1 < z < 1.3 were identified based on their red sequenc in the eFEDS point source catalog. Results. We examine the multiwavelength properties of these clusters and groups to understand the potential biases in our selection process and the completeness of the extent-selected sample. We find that the majority of the clusters and groups in the point source sample are indeed underluminous and compact compared to the extent-selected sample. Their faint X-ray emission, well below the flux limit of the extent-selected eFEDS clusters, and their compact X-ray emission are likely to be the main reason for this misclassification. In the sample, we confirm that 10% of the sources host AGN in their brightest cluster galaxies (BCGs) through optical spectroscopy and visual inspection. By studying their X-ray, optical, infrared, and radio properties, we establish a method for identifying clusters and groups that host AGN in their BCGs. We successfully test this method on the current point source catalog through the Sloan Digital Sky Survey optical spectroscopy and find eight low-mass clusters and groups with active radio-loud AGN that are particularly bright in the infrared. They include eFEDS J091437.8+024558, eFEDS J083520.1+012516, and eFEDS J092227.1+043339 at redshifts 0.3-0.4. Conclusions. This study helps us to characterize and understand our selection process and assess the completeness of the eROSITA extent-selected samples. The method we developed will be used to identify high-redshift clusters, AGN-dominated groups, and low-mass clusters that are misclassified in the future eROSITA all-sky survey point source catalogs.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Continuous assessment of metabolic activity of mitochondria using resonance Raman microspectroscopy

Dysfunctional mitochondrial activity can lead to a variety of different diseases. As such, there exists a need to quantify changes in mitochondria function as it relates to these specific diseased states. Here, we present the use of resonance Raman (RR) spectroscopy as a tool to determine changes in isolated mitochondrial activity. RR spectroscopy, using 532 nm as the excitation source, specifically provides information on the reduction and oxidation (RedOx) state of cytochrome c, which is determined by the activity of protein complexes in the electron transport chain. In this model, injection of the substrate succinate into the mitochondrial sample is used to drive the electron transport chain, which causes a subsequent change in cytochrome c RedOx state. This change in RedOx state is tracked by RR spectroscopy. We report this tool gives real-time information on the rise and fall of the amount of reduced cytochrome c within the mitochondrial sample, providing a method for rapid assessment of mitochondrial metabolism that has broad applications in both basic science and medical research.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2012

GEMINI MULTI-OBJECT SPECTROGRAPH SPECTROSCOPY OF EXO 0748-676 (=UY Vol) IN OUTBURST

We present a phase-resolved, optical, spectroscopic study of the eclipsing low-mass X-ray binary, EXO 0748-676 = UY Vol. The sensitivity of Gemini, combined with our complete phase coverage, makes for the most detailed blue spectroscopic study of this source obtained during its extended 24 year period of activity. We identify 12 optical emission lines and present trailed spectra, tomograms, and the first modulation maps of this source in outburst. The strongest line emission originates downstream of the stream-impact point, and this component is quite variable from night to night. Underlying this is weaker, more stable axisymmetric emission from the accretion disk. We identify weak, sharp emission components moving in phase with the donor star, from which we measure K{sub em} = 329 {+-} 26 km s{sup -1}. Combining all the available dynamical constraints on the motion of the donor star with our observed accretion disk velocities, we favor a neutron star mass close to canonical (M{sub 1} {approx_equal} 1.5 M{sub Sun }) and a very low mass donor (M{sub 2} {approx_equal} 0.1 M{sub Sun }). We note, however, that there is no evidence for CNO processing, which is often associated with undermassive donor stars. A main-sequence donor would require both a neutron star more massive than 2 M{sub Sun }, and substantially sub-Keplerian disk emission.

79 ASTRONOMY AND ASTROPHYSICS↗