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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Sediment Properties: E-Area Completion Project

To accommodate a future need for additional waste disposal facilities at the Savannah River Site, the Solid Waste Management Division (SWMD) designated nine additional plots for development (Kasraii 2007; SRS 2010); these plots are collectively known as the E Area Completion Project (ECP). Subsurface samples were collected from ECP plots 6, 7, 8 and 9 (Figure 1) for chemical and physical property analyses to support Performance Assessment (PA) and Special Analyses (SA) modeling. This document summarizes the sampling and analysis scheme and the resultant data, and provides interpretations of the data particularly in reference to existing soil property data. Analytical data in this document include: gamma log, cone penetrometer log, grain size (sieve and hydrometer), water retention, saturated hydraulic conductivity (falling head permeameter), porosity, dry bulk density, total organic carbon, x-ray diffraction, and x-ray fluorescence data. SRNL provided technical and safety oversight for the fieldwork, which included completion of eight soil borings, four geophysical logs, and the collection of 522 feet of core and 33 Shelby tubes from ECP plots 6, 7, 8, and 9. Boart Longyear provided sonic drilling and logging services. Two soil borings were completed at each location. The first set of boreholes extended into (but did not fully penetrate) the Warley Hill Formation. These boreholes were continuously cored, then geophysically (gamma ray) logged. The recovered core was split, photographed, and described; one half of the core was archived at SRS's Core Lab facilities, and the remaining half was consumed as necessary for testing at SRS and off-site labs. Core descriptions and geophysical data were used to calculate target elevations for Shelby tube samples, which were obtained from the second set of boreholes. Shelby tubes were shipped to MACTEC Engineering and Consulting Inc. (MACTEC) in Atlanta for physical property testing. SRNL deployed their Site Characterization and Analysis Penetrometer System (SCAPS) cone penetrometer test (CPT) truck at ECP plots 6, 7, 8 and 9 to collect inferred lithology data for the vadose zone. Results from this study are used to make recommendations for future modeling efforts involving the ECP plots. The conceptual model of the ECP hydrogeology differs from the conceptual model of the current ELLWF disposal area in that for the ECP plots, the topography (ground surface) is generally lower in elevation; The Upland and top of Tobacco Road lithostratigraphic units are missing (eroded); The water table occurs lower in elevation (i.e., it occurs in lower stratigraphic units); and the Tan Clay Confining Zone (TCCZ) often occurs within the vadose zone (rather than in the saturated zone). Due to the difference in the hydrogeology between the current ELLWF location and the ECP plots, different vadose zone properties are recommended for the ECP plots versus the properties recommended by Phifer et al. (2006) for the current disposal units. Results from this study do not invalidate or conflict with the current PA's use of the Upper and Lower Vadose Zone properties as described by Phifer et al. (2006) for the current ELLWF disposal units. The following modeling recommendations are made for future modeling of the ECP plots where vadose zone properties are required: (1) If a single vadose zone property is preferred, the properties described by Phifer et al. (2006) for the Upper Vadose Zone encompass the general physical properties of the combined sands and clays in the ECP vadose zone sediments despite the differences in hydrostratigraphic units. (2) If a dual zone system is preferred, a combination of the Lower Zone properties and the Clay properties described by Phifer et al. (2006) are appropriate for modeling the physical properties of the ECP vadose zone. The Clay properties would be assigned to the Tan Clay Confining Zone (TCCZ) and any other significant clay layers, while the Lower Zone properties would be assigned for the remainder of the vadose zone. No immediate updates or changes are recommended for the saturated zone properties for modeling of the ECP plots. The hydrogeology and saturated hydraulic conductivity values resulting from the ECP work are consistent with existing data for the area. The following recommendations are provided for consideration in future work: (1) When the database is next updated, we recommend checking/refining hydrostratigraphic interpretations (picks) in addition to revising physical property data for both the vadose zone and saturated zone. (2) Results from this work suggest that separate ECP vadose zone properties may be appropriate for the various ECP plots. Consideration should be given to the fact that the plots toward the northwest (ECP plots 6, 7 and 8) all have the TCCZ within the vadose zone whereas the TCCZ occurs within the saturated zone to the east (ECP plot 9). (3) Further data may be needed at ECP plot 7.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Inferring Netflow Data

Netflow data is a specific format for looking at network traffic. With this format, many security tests are easy to run. Cloud Service Providers produce logs that do not contain all of the content that Netflow data contains. There is a possibility that the fields that are in Netflow data but absent in Cloud Service Provider logs can be inferred from the fields that are present in the Cloud Service Provider logs. By inferring the missing data fields, the same test that can be run with Netflow data would be possible to run on the logs produced by Cloud Service Providers. Cloud Service Providers include Amazon Web Services and Box.com. There are multiple different types of Cloud Services, and each provider handles them differently and produces different logs. There are IaaS (meaning infrastructure as a service), Saas (meaning software as a service), and Paas (meaning platform as a service). Each provides a different use for the user.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

GlideinMonitor

This document describes GlideinMonitor. GlideinMonitor is a Web application that allows viewing of GlideinWMS’s Glidein log files: it provides a user interface, tools to do quick searches and to decode the log content; it provides an efficient managed archive of the log files and a framework to add log processing, e.g. log sanitation.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Geothermal Play-Fairway Analysis of Washington State Prospects: Final Report

The Washington State Geothermal Play-Fairway Analysis overcomes the exploration challenges posed by dense vegetation, glacial deposits, and extreme precipitation. The geothermal play-fairways we target are locations where heat, permeability, and saturated porosity are present in sufficient volume to provide adequate heat exchange at depths accessible by modern drilling technology. The three study areas lie along the Cascade Range magmatic arc and are near Mount Baker, Mount St. Helens, and the Wind River Valley. The seven-year project is divided into three phases. In Phase 1 we build on a previous statewide assessment of geothermal resources and develop an initial modeling approach. The results are a series of favorability, uncertainty, and risk maps for three targeted study areas. Based on these initial results, we collect new geologic and geophysical data to further refine our modeling and reduce exploration uncertainty in Phase 2. We improve the modeling method to handle the new data and update the favorability, uncertainty, and risk maps. We also update the conceptual geothermal resource models. In Phase 3 we validate our modeling approach by drilling two temperature-gradient holes and collecting and analyzing core, image logs, and new geochemistry. Our modeling approach improves on an earlier statewide method through a more-rigorous and detailed assessment of heat and permeability. Permeability potential is assessed through geomechanical modeling of the deformation that can generate and maintain reservoir porosity and permeability. Metrics to inform heat potential include temperature-gradient wells, which are sparse in Washington; proximity of Quaternary volcanic vents and young intrusive rock; spring temperature; and reservoir temperature inferred from geothermometry. We weight the individual components using an expert-guided approach known as the Analytical Hierarchy Process. During Phase 2 we also develop a fluid-filled fracture model, and an infrastructure model that helps to delineate areas which are more favorable for geothermal development based on proximity to transmission lines, elevation, land ownership and use restrictions, and availability of process water. New geologic and geophysical data is collected during Phase 2 in each of our three main study areas. At Mount Baker and north of Mount St. Helens we conduct 1:24,000-scale geologic mapping and lidar analysis to better constrain the location and character of surface faults; detailed mapping in the Wind River Valley was completed just prior to the start of this project. Ages of intrusive rocks are determined with 40 Ar/ 39 Ar geochronology, though all of our samples are Miocene or older. We collect ground based gravity observations (a total of 1,580 new stations) in all of our study areas and ground-based magnetic lines (a total of 93 km) at Mount Baker. These data are combined with existing gravity and aeromagnetic data and used to constrain fault locations and geometry. Two to three cross sections are constructed at each study area using the mapped surface geology and forward-modeling of the gravity and magnetic data; these cross sections form the basis for our updated conceptual models. We collect magnetotelluric surveys at Mount Baker and Mount St. Helens and these data are inverted to form a resistivity model from the surface to about 10 km depth; each model shows conductive zones that can be interpreted as upwelling geothermal fluids. At Mount St. Helens we deploy a passive seismic array and use the newly detected events to refine the location of the Saint Helens seismic zone. We also employ ambient-noise tomography to develop a detailed seismic-velocity model for the study area and use this model to help constrain our cross sections and conceptual model. Based on the new data collected during Phase 2—and our updated models—we develop a campaign of temperature-gradient holes and core analysis to validate our modeling in Phase 3. Drill hole MB76-31 is located near Little Park Creek, 11 km west-southwest of the summit of Mount Baker, and is 1,471 ft deep. About 410 ft of core from the lower portion of the hole—and image logs from ~175 ft below ground surface to the bottom—are collected and analyzed. Water samples are collected and processed for geothermometry. Drill hole MSH17-24 is located along upper Schultz Creek, 16 km north-northeast of Mount St. Helens and has core from 470 ft to the bottom at 1,053 ft. We did not collect image logs due to borehole stability concerns, but water samples are collected and analyzed for geothermometry. Repeat temperature-gradient measurements are made at both sites and thermal conductivity is measured from core samples. At MB76-31, the equilibrated temperature gradient of 64°C/km and calculated heat flow of 141–159 mW/m 2 is more than twice the regional average. Detailed mapping and analysis of the core, coupled with correlation to the image logs, indicates a history of permeability generation consistent with our predictions of high permeability. Because the site has high favorability in the Phase 2 model, we consider the results a positive validation of the modeling. At site MSH17-24, the equilibrated temperature gradient of ~15°C/km and calculated heat flow of 41–43 mW/m 2 are similar to regional. Geochemical analysis of the water samples indicates a meteoric source without any geothermal component. Detailed outcrop-based mapping of fault exposures near the drill site and analysis of image logs from nearby boreholes indicates a history of permeability generation consistent with our predictions. Because the site has low favorability in the Phase 2 model, we consider the results a positive validation of the modeling. Together, the two sites provide a reasonably positive validation of the Phase 2 modeling and should encourage future use of this modeling approach.

15 GEOTHERMAL ENERGY↗
DOE OSTI2016

Hot subdwarf stars observed in LAMOST DR1—atmospheric parameters from single-lined spectra

We present a catalog of 166 spectroscopically identified hot subdwarf stars from LAMOST DR1, 44 of which show the characteristics of cool companions in their optical spectra. Atmospheric parameters of 122 subdwarf stars with non-composite spectra were measured by fitting the profiles of hydrogen (H) and helium (He) lines with synthetic spectra from non-LTE model atmospheres. Most of the sdB stars scatter near the Extreme Horizontal Branch in the T{sub eff}–logg diagram and two well defined groups can be outlined. A clustering of He-enriched sdO stars appears near T{sub eff} = 45,000 K and log g = 5.8. The sdB population separates into several nearly parallel sequences in the T{sub eff}–He abundance diagram with clumps corresponding to those in the T{sub eff}–log g diagram. Over 38,000 K (sdO) stars show abundance extremes; they are either He-rich or He-deficient and we observe only a few stars in the abundance range −1<log y<0. With increasing temperature these extremes become less prominent and the He abundance approaches log y ∼ −0.5. A unique property of our sample is that it covers a large range in apparent magnitude and galactic latitude, therefore it contains a mix of stars from different populations and galactic environments. Our results are consistent with the findings of Hirsch and we conclude that He-rich and He-deficient sdB stars (log y < 1) probably originate from different populations. We also find that most sdO and sdB stars lie in a narrow strip in the plane of luminosity and helium abundance, which suggests that these atmospheric parameters are correlated.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

A NEW STATISTICAL PERSPECTIVE TO THE COSMIC VOID DISTRIBUTION

In this study, we obtain the size distribution of voids as a three-parameter redshift-independent log-normal void probability function (VPF) directly from the Cosmic Void Catalog (CVC). Although many statistical models of void distributions are based on the counts in randomly placed cells, the log-normal VPF that we obtain here is independent of the shape of the voids due to the parameter-free void finder of the CVC. We use three void populations drawn from the CVC generated by the Halo Occupation Distribution (HOD) Mocks, which are tuned to three mock SDSS samples to investigate the void distribution statistically and to investigate the effects of the environments on the size distribution. As a result, it is shown that void size distributions obtained from the HOD Mock samples are satisfied by the three-parameter log-normal distribution. In addition, we find that there may be a relation between the hierarchical formation, skewness, and kurtosis of the log-normal distribution for each catalog. We also show that the shape of the three-parameter distribution from the samples is strikingly similar to the galaxy log-normal mass distribution obtained from numerical studies. This similarity between void size and galaxy mass distributions may possibly indicate evidence of nonlinear mechanisms affecting both voids and galaxies, such as large-scale accretion and tidal effects. Considering the fact that in this study, all voids are generated by galaxy mocks and show hierarchical structures in different levels, it may be possible that the same nonlinear mechanisms of mass distribution affect the void size distribution.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

The effect of variability on X-ray binary luminosity functions: multiple-epoch observations of NGC 300 with Chandra

We have obtained three epochs of Chandra ACIS-I observations (totaling ∼184 ks) of the nearby spiral galaxy NGC 300 to study the logN–logS distributions of its X-ray point-source population down to ∼2 × 10{sup −15} erg s{sup −1} cm{sup −2} in the 0.35–8 keV band (equivalent to ∼10{sup 36} erg s{sup −1}). The individual epoch logN–logS distributions are best described as the sum of a background active galactic nucleus (AGN) component, a simple power law, and a broken power law, with the shape of the logN–logS distributions sometimes varying between observations. The simple power law and AGN components produce a good fit for “persistent” sources (i.e., with fluxes that remain constant within a factor of ∼2). The differential power-law index of ∼1.2 and high fluxes suggest that the persistent sources intrinsic to NGC 300 are dominated by Roche-lobe-overflowing low-mass X-ray binaries. The variable X-ray sources are described by a broken power law, with a faint-end power-law index of ∼1.7, a bright-end index of ∼2.8–4.9, and a break flux of ∼8×10{sup −15} erg s{sup −1} cm{sup −2} (∼4 × 10{sup 36} erg s{sup −1}), suggesting that they are mostly outbursting, wind-fed high-mass X-ray binaries, although the logN–logS distribution of variable sources likely also contains low-mass X-ray binaries. We generate model logN–logS distributions for synthetic X-ray binaries and constrain the distribution of maximum X-ray fluxes attained during outburst. Our observations suggest that the majority of outbursting X-ray binaries occur at sub-Eddington luminosities, where mass transfer likely occurs through direct wind accretion at ∼1%–3% of the Eddington rate.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Hints on the Gradual Resizing of the Torus in AGNs through Decomposition of Spitzer/IRS Spectra

Several authors have claimed that less luminous active galactic nuclei (AGNs) are not capable of sustaining a dusty torus structure. Thus, a gradual resizing of the torus is expected when the AGN luminosity decreases. Our aim is to examine mid-infrared observations of local AGNs of different luminosities for the gradual resizing and disappearance of the torus. We applied the decomposition method described by Hernán-Caballero et al. to a sample of ∼100 Spitzer/IRS spectra of low-luminosity AGNs and powerful Seyferts in order to decontaminate the torus component from other contributors. We have also included Starburst objects to ensure secure decomposition of the Spitzer/IRS spectra. We have used the affinity propagation (AP) method to cluster the data into five groups within the sample according to torus contribution to the 5–15 μm range (C{sub torus}) and bolometric luminosity (L{sub bol}). The AP groups show a progressively higher torus contribution and an increase of the bolometric luminosity from Group 1 (C{sub torus}∼0% and log(L{sub bol})∼41) up to Group 5 (C{sub torus}∼80% and log(L{sub bol})∼44). We have fitted the average spectra of each of the AP groups to clumpy models. The torus is no longer present in Group 1, supporting its disappearance at low luminosities. We were able to fit the average spectra for the torus component in Groups 3 (C{sub torus}∼40% and log(L{sub bol})∼42.6), 4 (C{sub torus}∼60% and log(L{sub bol})∼43.7), and 5 to Clumpy torus models. We did not find a good fitting to Clumpy torus models for Group 2 (C{sub torus}∼18% and log(L{sub bol})∼42). This might suggest a different configuration and/or composition of the clouds for Group 2, which is consistent with the different gas content seen in Groups 1, 2, and 3, according to detections of H{sub 2} molecular lines. Groups 3, 4, and 5 show a trend of decreasing torus width (which leads to a likely decrease of the geometrical covering factor), although we cannot confirm it with the present data. Finally, Groups 3, 4, and 5 show an increase of the outer radius of the torus for higher luminosities, consistent with a resizing of the torus according to AGN luminosity.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Tripling the Census of Dwarf AGN Candidates Using DESI Early Data

Using early data from the Dark Energy Spectroscopic Instrument (DESI) survey, we search for active galactic nuclei (AGN) signatures in 410,757 line-emitting galaxies. By employing the BPT emission-line ratio diagnostic diagram, we identify AGNs in 75,928/296,261 (≈25.6%) high-mass ($\mathrm{log}({M}_{\star }/{M}_{\odot })\,\gt$ 9.5) and 2444/114,496 (≈2.1%) dwarf ($\mathrm{log}({M}_{\star }/{M}_{\odot })\,\leqslant$ 9.5) galaxies. Of these AGN candidates, 4181 sources exhibit a broad Hα component, allowing us to estimate their BH masses via virial techniques. This study more than triples the census of dwarf AGNs and doubles the number of intermediate-mass black hole (M BH ≤ 10 6 M ⊙ ) candidates, spanning a broad discovery space in stellar mass (7 $\lt \mathrm{log}({M}_{\star }/{M}_{\odot })\,\lt$ 12) and redshift (0.001 < z < 0.45). The observed AGN fraction in dwarf galaxies (≈2.1%) is nearly four times higher than prior estimates, primarily due to DESI’s smaller fiber size, which enables the detection of lower-luminosity dwarf AGN candidates. We also extend the M BH –M⋆ scaling relation down to ${\rm{log}}({M}_{\star }/{M}_{\odot })\,\approx$ 8.5 and $\mathrm{log}({M}_{\mathrm{BH}}/{M}_{\odot })\,\approx$ 4.4, with our results aligning well with previous low-redshift studies. The large statistical sample of dwarf AGN candidates from current and future DESI releases will be invaluable for enhancing our understanding of galaxy evolution at the low-mass end of the galaxy mass function.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1993

The Lyman alpha forest of the high-z quasar 0000-263

Medium-resolution (delta(v) = 45 km/s) optical spectra of the bright, high-redshift (z = 4.1) quasar 0000-263 taken at the ESO 3.5-m NTT telescope were analyzed to determine the distribution of column densities, velocities and line widths of the Lyman-alpha forest absorption components. The values of NH, b, and z were determined by fitting Voigt profiles to the lines, and convolving with a Gaussian instrumental response function. Over 350 components with log N(sub H) greater than 13.2 were identified. An analysis of the dependence of the number of components with z reveals that the number evolution of components obeys the power law dN/dz varies as (1+z)(sup gamma), where gamma = 0.5 +/- 0.4 for the sample of 182 lines with log N(sub H) greater than 14.0. The distribution of component strengths is found to obey f(N(sub H)) varies as N(sub h)(sup -beta), where beta = -1.55 for components with log(N(sub H)) is greater than 14.7, and beta = -0.68 for the components with log(N(sub H)) greater than 13.5. A distinct break in the f(N(sub H)) histogram is also observed, at log(N(sub H)) is approximately 14.7. The results are briefly considered in the context of theoretical models of quasar Lyman alpha clouds and their evolution.

Penprase, Bryan↗
NASA NTRS1993

The optically thick C III spectrum. 2: Level/term populations and line/multiplet intensities using an improved hybrid model

An improved hybrid level/term calculation is employed to obtain C III level/term populations and line/fractional multiplet intensities over the extended range of electron density 4.0 less than or equal log N(sub e) less than or equal 12.0, for column lengths L ranging from zero (optically thin) to 10(exp 20)/sq cm (moderately optically thick), at electron temperatures T(sub e) approximately 40,000 K(log T(sub e) = 4.6), T(sub e) approximately 63,000 K (log T(sub e) = 4.8), T(sub e) approximately 79,500 K (log T(sub e) = 4.9), and T(sub e) = 100,000 K (log T(sub e) = 5.0). The tabulated results are relevant to the interpretation of space observations obtained over extended spectral ranges by new and planned facilities including the Hopkins Ultraviolet Telescope (HUT) and the Far-Ultraviolet Spectrographic Explorer (FUSE).

Bhatia, A. K.↗
NASA NTRS1995

Probing the galactic disk and halo. 2: Hot interstellar gas toward the inner galaxy star HD 156359

We present Goddard High Resolution Spectrograph intermediate-resolution measurements of the 1233-1256 A spectral region of HD 156396, a halo star at l = 328.7 deg, b = -14.5 deg in the inner Galaxy with a line-of sight distance of 11.1 kpc and a z-distance of -2.8 kpc. The data have a resolution of 18 km/s Full Width at Half Maximum (FWHM) and a signal-to-noise ratio of approximately 50:1. We detect interstellar lines of Mg II, S II, S II, Ge II, and N V and determine log N/(Mg II) = 15.78 +0.25, -0.27, log N(Si II) greater than 13.70, log N(S II) greater than 15.76, log N(Ge II) = 12.20 +0.09,-0.11, and log N(N v) = 14.06 +/- 0.02. Assuming solar reference abundances, the diffuse clouds containing Mg, S, and Ge along the sight line have average logarithmic depletions D(Mg) = -0.6 +/- 0.3 dex, D(S) greater than -0.2 dex, and D(Ge) = -0.2 +/- 0.2 dex. The Mg and Ge depletions are approximately 2 times smaller than is typical of diffuse clouds in the solar vicinity. Galactic rotational modeling of the N v profiles indicates that the highly ionized gas traced by this ion has a scale height of approximately 1 kpc if gas at large z-distances corotates with the underlying disk gas. Rotational modeling of the Si iv and C iv profiles measured by the IUE satellite yields similar scale height estimates. The scale height results contrast with previous studies of highly ionized gas in the outer Milky Way that reveal a more extended gas distribtion with h approximately equals 3-4 kpc. We detect a high-velocity feature in N v and Si II v(sub LSR) approximately equals + 125 km/s) that is probably created in an interface between warm and hot gas.

Sembach, Kenneth R.↗
NASA NTRS2007

The Hottest Horizontal-Branch Stars in Omega Centauri: Late Hot Flasher vs. Helium Enrichment

UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario here stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified from existing data. We want to determine effective temperatures, surface gravities and abundances of He, C, N in blue hook and canonical extreme horizontal branch (EHB) star candidates. Moderately high resolution spectra of stars at the hot end of the blue horizontal branch in the globular cluster omega Cen were analysed for atmospheric parameters (T(sub eff), log g) and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 37% of our stars are helium-poor (log nHe/nH less than -2), 49% have solar helium abundance within a factor of 3 (-1.5 less than or equal to log nHe/nH less than or equal to -0.5) and 14% are helium rich (log nHe/nH greater than -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 30% of the hottest HB stars in omega Centauri show helium abundances well above the predictions from the helium enrichment scenario (Y = 0.42 corresponding to log nHe/nH approximately equal to -0.74). In addition the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

Moehler, S.↗
NASA NTRS2017

Feeding and Feedback in the Powerful Radio Galaxy 3C 120

We present a spectral analysis of a 200-kilosecond observation of the broad-line radio galaxy 3C 120, performed with the high-energy transmission grating spectrometer on board the Chandra X-Ray Observatory. We find (i) a neutral absorption component intrinsic to the source with a column density of log N (sub H) equals 20.67 plus or minus 0.05 square centimeters; (ii) no evidence for a warm absorber (WA) with an upper limit on the column density of just log N (sub H) less than 19.7 square centimeters, assuming the typical ionization parameter log xi approximately equal to 2.5 ergs per second per centimeter; the WA may instead be replaced by (iii) a hot emitting gas with a temperature kT approximately equal to 0.7 kiloelectronvolts observed as soft X-ray emission from ionized Fe L-shell lines, which may originate from a kiloparsec-scale shocked bubble inflated by the active galactic nucleus (AGN) wind or jet with a shock velocity of about 1000 kilometers per second determined by the emission line width; (iv) a neutral Fe K alpha line and accompanying emission lines indicative of a Compton-thick cold reflector with a low reflection fraction R approximately equal to 0.2, suggesting a large opening angle of the torus; (v) a highly ionized Fe XXV emission feature indicative of photoionized gas with an ionization parameter log xi equal to 3.75 (sup plus 0.38) (sub minus 0.27) ergs per second per centimeter and a column density of log N (sub H) greater than 22 square centimeters localized within approximately 2 pc from the X-ray source; and (vi) possible signatures of a highly ionized disk wind. Together with previous evidence for intense molecular line emission, these results indicate that 3C 120 is likely a late-state merger undergoing strong AGN feedback.

black hole physics – galaxies: active – line: ↗
DOE OSTI2018

National Plan for the Disposal of Existing and Future TRU Wastes - 18616

Now that the Waste Isolation Pilot Plant (WIPP) has re-opened, after being down for three years due to an accident the DOE National TRU Program has re-developed a plan for the disposal of existing and future TRU wastes. The National TRU Waste Management Plan (NTWMP) is an integrated plan to address the needs of DOE sites across the DOE Weapons Complex that create and store TRU waste, and is centered on the capability of WIPP to receive and dispose of TRU waste. The WIPP capability is planned as a weekly shipping rate and is defined by emplacement and receipt rate capabilities since WIPP is not permitted for long-term storage. And, shipping rates may be constrained by new WIPP Waste Acceptance Criteria (WAC) and future plans for repository configurations and disposal package capabilities over the next 30 years. Since WIPP is the only disposal system available to the DOE for TRU waste disposal, DOE has a newly projected life-cycle need for WIPP to remain open and available up to 2050. It is projected that the need for WIPP will continue up to the year 2050 for the disposition of the remaining legacy TRU inventories and for the disposal of TRU waste continuing to be generated at DOE's National Laboratories. In addition, there are several other potential new waste streams in which WIPP is being considered an alternative solution for their disposition. The NTWMP has been updated to reflect the short-term and long-term plans for TRU waste disposal at WIPP. The short-term plan is used by DOE for budget projection and integration purposes to facilitate and inform budget planning, both in DOE's Environmental Management (EM) and National Nuclear Security Administration (NNSA) organizations. Most legacy TRU waste (generated in the past and stored at DOE sites today) is owned and managed by EM. And, EM submits integrated budget requests for DOE sites, including the integration of resources for TRU waste management. NNSA and DOE's Office of Science (OS) funds TRU waste management as part of their mission funding and NNSA should eventually be the primary user of the WIPP resources as EM's legacy TRU waste is cleaned-up. Prior to the unexpected shutdown of WIPP in 2014, there was a small back-log of waste certified for WIPP disposal and shipments of TRU waste to WIPP were 'just-in-time' as waste was certified. After three years of WIPP being down, DOE sites have built significant back-logs of TRU waste to be certified for WIPP. That back-log built up to over 25,000 containers of TRU waste during that three-year period (Table 1). The backlog included both Contact-Handled (CH) TRU waste and Remote-Handled (RH) TRU waste, and even though WIPP re-opened in April of 2017, it is only open for TRU waste containers that can be stacked on disposal room floors. Plans for changing RH waste disposal packages and methods are in-the-works, but are not yet mature enough for significant planning. In addition, the WIPP underground facilities are now partially contaminated with radioactive particulate, which significantly reduces the WIPP operational efficiencies as compared to 2014. With a large back-log of waste ready for WIPP disposal and limited throughput for WIPP disposal rates, the focus of the NTWMP is to prioritize the selection of TRU wastes from the various sites based on WIPP waste emplacement rates and shipping rates to WIPP. Some TRU waste sites have a significant need to be top priority for shipments to WIPP, and that must be balanced with the need for all TRU waste sites to have some shipments to deplete their back-log of TRU wastes. Storage and management of TRU waste is very costly for DOE and many of those resources could be used to optimize the overall disposition of TRU waste and save DOE significant funding. In addition, the plan will show the possible transition of TRU Waste Management from primarily being an EM function to being an NNSA function in the coming years. As legacy TRU waste inventories are removed, and as NNSA mission-related TRU waste inventories are produced, DOE will be faced with deciding where the primary responsibility for TRU waste management should reside. (author)

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

Evaluation of Drilling Performance at The Geysers with Machine Learning Methods Using Geologic Data

A recent well, GDC-36, was drilled in The Geysers Geothermal Field served in a Department of Energy-industry to demonstrate improved drilling performance with polycrystalline diamond compact (PDC) bits. Both PDC and roller cone drill bits were used to drill this well. Key challenges encountered during drilling included lost circulation in the mud-drilled section, and bit damage interfacial severity in the deeper, air-drilled section. The objective of this study is to evaluate the drilling performance in relation to the local geological characteristics using machine learning methods. By applying K-clustering to the sonic log data, we were able to identify areas correlated with measured lost circulation. Also, the boundaries defined by clustering of the mineralogical and lithological data from the mud logs correlate well with interfacial severity during drilling. A random forest model was employed to build correlation between drilling data and rock strength. The confined compressive strength (CCS) of the rock in the training of the machine learning model was inferred from the dipole sonic log. The R-squared of the testing data is 0.78, and the RMSE (Root Mean Squared Error) is 0.06. The trained model was used to forecast rock strength for the section where sonic log data are not available. CCS could also be inferred from mud logs provided the relationship between mineralogy and rock strength is established through core testing data.

15 GEOTHERMAL ENERGY↗
DOE OSTI2023

Utah FORGE 2439: Well 16B(78)-32 Field-Test Data from Mini-Frac Tests

This submittal includes the field-test data collected during stress tests conducted in the Utah FORGE 16B(78)-32 wellbore to measure/characterize the stresses in the geothermal reservoir. The type of stress test performed is referred to as a mini-frac test or a micro-frac test. The test is a hydraulic fracture test that involves injecting a small volume of water into a short interval of the reservoir that is isolated by a straddle packer to create a fracture. The test provides information about the minimum and maximum horizontal stress at the test depths. A total of seven mini-frac tests were performed within the upper (vertical or nearly vertical) section of the 9-5/8-inch diameter uncased wellbore, between depths of 5,202 ft MD [5,202 ft TVD] and 5,980 ft MD [5966.18 ft TVD]. Two types of data were generated as part of the mini-frac tests. The first type of data is time-series data for each mini-frac test (e.g., injection-rate, test-interval pressure), and are contained in the "Mini-Frac Test Data.zip" file below. The second type is geophysical log data, attached below in the "Geophysical Logs.zip" file. Here, two types of image logs and acoustic logs were obtained before and after the mini-frac tests to examine each test depth for visual evidence of induced fracture(s) and to measure the azimuth (orientation) of any observed fractures. The attached Readme file includes the test depth information and contents of each data file included here. Analysis of the field-test data was conducted and is documented in the attached report below.

15 GEOTHERMAL ENERGY↗
DOE OSTI2019

A probabilistic perspective on thermodynamic parameter uncertainties: Understanding aqueous speciation of mercury

Speciation plays an important role in determining the fate and transport of metals in terrestrial surface and subsurface systems. Equilibrium speciation modeling in aqueous systems relies on thermodynamic constants (log K values) of complexes, which are subject to uncertainties. In this study, using Monte Carlo (MC) simulations with Latin hypercube sampling (LHS) we systematically analyze the propagation of thermodynamic constant uncertainty through speciation modeling of an inorganic mercury-sulfide-chloride-water system. We find that seemingly small variances of the input log K normal distributions can lead to output species concentrations spanning multiple orders of magnitude, with highly skewed probability distributions. When equilibrium with mineral metacinnabar (β-HgS(s)) is neglected, the relative uncertainty of each output species is strongly positively correlated with the skewness of its concentration probability distribution, i.e., the lowest uncertainty occurs when the species concentration probability distribution is the most negatively skewed as its concentration approaches the total element concentration limit. The highest uncertainty in the identity of dominant species is located around species equivalence points. For cases where the mineral equilibrium is included, we derive analytical probability density functions for the log concentrations of all major species in the system. The mineral log K uncertainty is found to be an important contributor to all output concentration uncertainties. The analysis of combined effects of both pH and total sulfide concentration on output concentration uncertainties shows that high concentration uncertainties occur under highly sulfidic alkaline conditions and low uncertainties at low pH and sulfide concentrations. Finally, an analysis as presented here can distinguish between conditions that require a full uncertainty analysis and those for which the classical deterministic speciation modeling suffices.

58 GEOSCIENCES↗