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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 OSTI2011

Prospective Study Validating Inter- and Intraobserver Variability of Tissue Compliance Meter in Breast Tissue of Healthy Volunteers: Potential Implications for Patients With Radiation-Induced Fibrosis of the Breast

Purpose: Accurate detection of radiation-induced fibrosis (RIF) is crucial in management of breast cancer survivors. Tissue compliance meter (TCM) has been validated in musculature. We validate TCM in healthy breast tissue with respect to interobserver and intraobserver variability before applying it in RIF. Methods and Materials: Three medical professionals obtained three consecutive TCM measurements in each of the four quadrants of the right and left breasts of 40 women with no breast disease or surgical intervention. The intraclass correlation coefficient (ICC) assessed interobserver variability. The paired t test and Pearson correlation coefficient (r) were used to assess intraobserver variability within each rater. Results: The median age was 45 years (range, 24-68 years). The median bra size was 35C (range, 32A-40DD). Of the participants, 27 were white (67%), 4 black (10%), 5 Asian (13%), and 4 Hispanic (10%). ICCs indicated excellent interrater reliability (low interobserver variability) among the three raters, by breast and quadrant (all ICC {>=}0.99). The paired t test and Pearson correlation coefficient both indicated low intraobserver variability within each rater (right vs. left breast), stratified by quadrant (all r{>=} 0.94, p < 0.0001). Conclusions: The interobserver and intraobserver variability is small using TCM in healthy mammary tissue. We are now embarking on a prospective study using TCM in women with breast cancer at risk of developing RIF that may guide early detection, timely therapeutic intervention, and assessment of success of therapy for RIF.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Glauber-based evaluations of the odd moments of the initial eccentricity relative to the even order participant plates

Monte Carlo simulations are used to compute the centrality dependence of the odd moments of the initial eccentricity {var_epsilon}{sub n+1}, relative to the even-order (n) participant planes {Psi}{sub n} in Au + Au collisions. The results obtained for two models of the eccentricity - the Glauber and the factorized Kharzeev-Levin-Nardi (fKLN) models - indicate magnitudes which are essentially zero. They suggest that a possible correlation between the orientations of the odd and even participant planes ({Psi}{sub n+1} and {Psi}{sub n}, respectively) does not have a significant influence on the calculated eccentricities. An experimental verification test for correlations between the orientations of the odd and even participant planes is also proposed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Initial experience of ArcCHECK and 3DVH software for RapidArc treatment plan verification

The purpose of this study was to perform delivery quality assurance with ArcCHECK and 3DVH system (Sun Nuclear, FL) and to evaluate the suitability of this system for volumetric-modulated arc therapy (VMAT) (RapidArc [RA]) verification. This software calculates the delivered dose distributions in patients by perturbing the calculated dose using errors detected in fluence or planar dose measurements. The device is tested to correlate the gamma passing rate (%GP) and the composite dose predicted by 3DVH software. A total of 28 patients with prostate cancer who were treated with RA were analyzed. RA treatments were delivered to a diode array phantom (ArcCHECK), which was used to create a planned dose perturbation (PDP) file. The 3DVH analysis used the dose differences derived from comparing the measured dose with the treatment planning system (TPS)-calculated doses to perturb the initial TPS-calculated dose. The 3DVH then overlays the resultant dose on the patient's structures using the resultant “PDP” beams. Measured dose distributions were compared with the calculated ones using the gamma index (GI) method by applying the global (Van Dyk) normalization and acceptance criteria, i.e., 3%/3 mm. Paired differences tests were used to estimate statistical significance of the differences between the composite dose calculated using 3DVH and %GP. Also, statistical correlation by means of logistic regression analysis has been analyzed. Dose-volume histogram (DVH) analysis for patient plans revealed small differences between treatment plan calculations and 3DVH results for organ at risk (OAR), whereas planning target volume (PTV) of the measured plan was systematically higher than that predicted by the TPS. The t-test results between the planned and the estimated DVH values showed that mean values were incomparable (p < 0.05). The quality assurance (QA) gamma analysis 3%/3 mm showed that in all cases there were only weak-to-moderate correlations (Pearson r: 0.12 to 0.74). Moreover, clinically relevant differences increased with increasing QA passing rate, indicating that some of the largest dose differences occurred in the cases of high QA passing rates, which may be called “false negatives.” The clinical importance of any disagreement between the measured and the calculated dose is often difficult to interpret; however, beam errors (either in delivery or in TPS calculation) can affect the effectiveness of the patient dose. Further research is needed to determinate the role of a PDP-type algorithm to accurately estimate patient dose effect.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2013

A Case Study Correlating Innovative Gamma Ray Scanning Detection Systems Data to Surface Soil Gamma Spectrometry Results - 13580

HydroGeoLogic (HGL), Inc. completed a United States Environmental Protection Agency (USEPA) study to characterize radiological contamination at a site near Canoga Park, California. The characterized area contained 470 acres including the site of a prototype commercial nuclear reactor and other nuclear design, testing, and support operations from the 1950's until 1988 [1]. The site history included radiological releases during operation followed by D and D activities. The characterization was conducted under an accelerated schedule and the results will support the project remediation. The project has a rigorous cleanup to background agenda and does not allow for comparison to risk-based guidelines. To target soil sample locations, multiple lines of evidence were evaluated including a gamma radiation survey, geophysical surveys, historical site assessment, aerial photographs, and former worker interviews. Due to the time since production and decay, the primary gamma emitting radionuclide remaining is cesium-137 (Cs-137). The gamma ray survey covered diverse, rugged terrain using custom designed sodium iodide thallium-activated (NaI(Tl)) scintillation detection systems. The survey goals included attaining 100% ground surface coverage and detecting gamma radiation as sensitively as possible. The effectiveness of innovative gamma ray detection systems was tested by correlating field Cs-137 static count ratios to Cs-137 laboratory gamma spectrometry results. As a case study, the area encompassing the former location of the first nuclear power station in the U. S. was scanned, and second by second global positioning system (GPS)-linked gamma spectral data were evaluated by examining total count rate and nuclide-specific regions of interest. To compensate for Compton scattering from higher energy naturally occurring radionuclides (U-238, Th-232 and their progeny, and K-40), count rate ratios of anthropogenic nuclide-specific regions of interest to the total count rate were calculated. From the scanning data, locations with observed Cs-137 ratios exceeding six standard deviations above the mean ratio were mapped in high resolution [2]. Field teams returned to those locations to collect static count measurements using the same detection systems. Soil surface samples were collected at 30 locations and analyzed for Cs-137. An exponential correlation was identified between Cs-137 concentrations in surface soil and field-scanned Cs-137 ratios. The data indicate field minimum detectable concentration (MDC) of Cs-137 at 0.02 Bq/g (0.5 pCi/g) or lower depending on contaminant distribution in soil. (authors)

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

Stellar Obliquity and Magnetic Activity of Planet-hosting Stars and Eclipsing Binaries Based on Transit Chord Correlation

The light curve of an eclipsing system shows anomalies whenever the eclipsing body passes in front of active regions on the eclipsed star. In some cases, the pattern of anomalies can be used to determine the obliquity Ψ of the eclipsed star. Here we present a method for detecting and analyzing these patterns, based on a statistical test for correlations between the anomalies observed in a sequence of eclipses. Compared to previous methods, ours makes fewer assumptions and is easier to automate. We apply it to a sample of 64 stars with transiting planets and 24 eclipsing binaries for which precise space-based data are available, and for which there was either some indication of flux anomalies or a previously reported obliquity measurement. We were able to determine obliquities for 10 stars with hot Jupiters. In particular we found Ψ ≲ 10° for Kepler-45, which is only the second M dwarf with a measured obliquity. The other eight cases are G and K stars with low obliquities. Among the eclipsing binaries, we were able to determine obliquities in eight cases, all of which are consistent with zero. Our results also reveal some common patterns of stellar activity for magnetically active G and K stars, including persistently active longitudes.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

A Standardized Analysis Process Using Digital Image Correlation to Calculate In Situ Cladding Strain from Modified Burst Tests for Fuel Performance Code Validation

Historical data collection on nuclear fuel cladding materials has focused on generating a statistically significant amount of data to assess the material and its failure behavior. Furthermore, data generated to support material model and failure criteria development were previously posttest evaluations, so a large number of tests was required to gain new understanding. A way to expedite this process is to develop techniques capable of generating large, high-fidelity data sets from a single test with lower uncertainty or quantified uncertainty. One such example of this approach is Oak Ridge National Laboratory’s use of modified burst tests (MBTs) to analyze the mechanical behavior and failure conditions of cladding during a simulated reactivity-initiated accident (RIA). Each test incorporates digital image correlation (DIC) analysis techniques that are used to assess the accumulated strain in situ, as well as eventual cladding failure. This work has been fruitful in defining strain-to-failure conditions for materials like silicon carbide (SiC) fiber–reinforced/SiC matrix composite tubes (SiC/SiC), iron-chromium-aluminum (FeCrAl) alloy tubes, and chromium-coated Zircaloy-4 tubes. However, there are numerous DIC software available, including open-source and proprietary software. The different DIC software use various algorithms to process images and calculate displacement values. Using these different software and algorithms can lead to varying results, and perhaps larger-than-expected uncertainties. In the present study, previously published MBT data encompassing a variety of test conditions were reanalyzed with two different DIC software to assess the variance in the calculated strain results. The data consisted of SiC/SiC, FeCrAl, and chromium-coated Zircaloy-4 tubes. Plots of the calculated strains during the transient revealed good agreement between the two DIC software. The average root-mean-square errors between the two software was 0.20% strain, which is slightly larger than a previously reported error value for these tests. In conclusion, this variance in results is low enough that this analysis method can be used for code validation.

Reactivity-initiated accident↗
DOE OSTI2013

Experimental and life cycle assessment analysis of gas emission from mechanically–biologically pretreated waste in a landfill with energy recovery

Highlights: • Bio-methane landfill emissions from different period (0, 4, 8, 16 weeks) MTB waste have been evaluated. • Electrical energy recoverable from landfill gas ranges from 11 to about 90 kW h/tonne. • Correlation between oxygen uptake, energy recovery and anaerobic gas production shows R{sup 2} ranging from 0.78 to 0.98. • LCA demonstrate that global impact related to gaseous emissions achieve minimum for 4 week of MBT. - Abstract: The global gaseous emissions produced by landfilling the Mechanically Sorted Organic Fraction (MSOF) with different weeks of Mechanical Biological Treatment (MBT) was evaluated for an existing waste management system. One MBT facility and a landfill with internal combustion engines fuelled by the landfill gas for electrical energy production operate in the waste management system considered. An experimental apparatus was used to simulate 0, 4, 8 and 16 weeks of aerobic stabilization and the consequent biogas potential (Nl/kg) of a large sample of MSOF withdrawn from the full-scale MBT. Stabilization achieved by the waste was evaluated by dynamic oxygen uptake and fermentation tests. Good correlation coefficients (R{sup 2}), ranging from 0.7668 to 0.9772, were found between oxygen uptake, fermentation and anaerobic test values. On the basis of the results of several anaerobic tests, the methane production rate k (year{sup −1}) was evaluated. k ranged from 0.436 to 0.308 year{sup −1} and the bio-methane potential from 37 to 12 N m{sup 3}/tonne, respectively, for the MSOF with 0 and 16 weeks of treatment. Energy recovery from landfill gas ranged from about 11 to 90 kW h per tonne of disposed MSOF depending on the different scenario investigated. Life cycle analysis showed that the scenario with 0 weeks of pre-treatment has the highest weighted global impact even if opposite results were obtained with respect to the single impact criteria. MSOF pre-treatment periods longer than 4 weeks showed rather negligible variation in the global impact of system emissions.

09 BIOMASS FUELS↗
DOE OSTI2017

Ab initio calculation of the potential bubble nucleus Si 34

Background: The possibility that an unconventional depletion (referred to as a “bubble”) happens in the middle of the charge density distribution of certain nuclei due to a purely quantum mechanical effect has attracted theoretical and experimental attention in recent years. Based on a mean-field rationale, a correlation between the occurrence of such a semibubble and an anomalously weak splitting between low angular-momentum spin-orbit partners has been further conjectured. Energy density functional and valence-space shell model calculations have been performed to identify and characterize the best candidates, among which Si 34 appears as a particularly interesting case. While the experimental determination of the charge density distribution of the unstable Si 34 is currently out of reach, ($d, p$) experiments on this nucleus have been performed recently to test the correlation between the presence of a bubble and an anomalously weak 1/2 – –3/2 – splitting in the spectrum of Si 35 as compared to S 37 . Purpose: We study the potential bubble structure of Si 34 on the basis of the state-of-the-art ab initio self-consistent Green's function many-body method. Methods: We perform the first ab initio calculations of Si 34 and S 36 . In addition to binding energies, the first observables of interest are the charge density distribution and the charge root-mean-square radius for which experimental data exist in S 36 . The next observable of interest is the low-lying spectroscopy of Si 35 and S 37 obtained from ($d, p$) experiments along with the spectroscopy of Al 33 and P 35 obtained from knock-out experiments. The interpretation in terms of the evolution of the underlying shell structure is also provided. The study is repeated using several chiral effective field theory Hamiltonians as a way to test the robustness of the results with respect to input internucleon interactions. The convergence of the results with respect to the truncation of the many-body expansion, i.e., with respect to the many-body correlations included in the calculation, is studied in detail. We eventually compare our predictions to state-of-the-art multireference energy density functional and shell model calculations. Results: The prediction regarding the (non)existence of the bubble structure in Si 34 varies significantly with the nuclear Hamiltonian used. Yet, demanding that the experimental charge density distribution and the root-mean-square radius of S 36 be well reproduced, along with Si 34 and S 36 binding energies, only leaves the NNLO sat Hamiltonian as a serious candidate to perform this prediction. In this context, a bubble structure, whose fingerprint should be visible in an electron scattering experiment of Si 34 , is predicted. Furthermore, a clear correlation is established between the occurrence of the bubble structure and the weakening of the 1/2 – –3/2 – splitting in the spectrum of Si 35 as compared to S 37 . Conclusions: The occurrence of a bubble structure in the charge distribution of Si 34 is convincingly established on the basis of state-of-the-art ab initio calculations. This prediction will have to be reexamined in the future when improved chiral nuclear Hamiltonians are constructed. On the experimental side, present results act as a strong motivation to measure the charge density distribution of Si 34 in future electron scattering experiments on unstable nuclei. In the meantime, it is of interest to perform one-neutron removal on Si 34 and S 36 in order to further test our theoretical spectral strength distributions over a wide energy range.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

Examination of the observability of a chiral magnetically driven charge-separation difference in collisions of the Ru 44 96 + Ru 44 96 and Zr 40 96 + Zr 40 96 isobars at energies available at the BNL Relativistic Heavy Ion Collider

Here, anomalous viscous fluid dynamics model calculations for Ru 44 96 + Ru 44 96 and Zr 40 96 + Zr 40 96 collisions ( s N N = 200 GeV) are used in concert with a charge-sensitive correlator to test its ability to detect and characterize the charge separation difference expected from the chiral magnetic effect (CME) in these isobaric collisions. The tests indicate a larger charge separation for Ru 44 96 + Ru 44 96 than for Zr 40 96 + Zr 40 96 collisions and a discernible CME-driven difference of ~ 10 % in the presence of realistic non-CME backgrounds. Furthermore, they suggest a strategy for evaluating the relative influence of the background correlations, present for each isobar. These results suggest that charge-separation measurements for these isobaric species could serve to further constrain unambiguous identification and characterization of the CME in upcoming measurements at the Relativistic Heavy Ion Collider

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Utilization of localized panel resonant behavior in wind turbine blades.

The shear webs and laminates of core panels of wind turbine blades must be designed to avoid panel buckling while minimizing blade weight. Typically, buckling resistance is evaluated by consideration of the load-deflection behavior of a blade using finite element analysis (FEA) or full-scale static loading of a blade to failure under a simulated extreme loading condition. This paper examines an alternative means for evaluating blade buckling resistance using non-destructive modal tests or FEA. In addition, panel resonances can be utilized for structural health monitoring by observing changes in the modal parameters of these panel resonances, which are only active in a portion of the blade that is susceptible to failure. Additionally, panel resonances are considered for updating of panel laminate model parameters by correlation with test data. During blade modal tests conducted at Sandia Labs, a series of panel modes with increasing complexity was observed. This paper reports on the findings of these tests, describes potential ways to utilize panel resonances for blade evaluation, health monitoring, and design, and reports recent numerical results to evaluate panel resonances for use in blade structural health assessment.

17 WIND ENERGY↗
DOE OSTI2013

Mechanisms Underpinning Degradation of Protective Oxides and Thermal Barrier Coatings in High Hydrogen Content (HHC) - Fueled Turbines

The overarching goal of this research program has been to evaluate the potential impacts of coal-derived syngas and high-hydrogen content fuels on the degradation of turbine hot-section components through attack of protective oxides and thermal barrier coatings. The primary focus of this research program has been to explore mechanisms underpinning the observed degradation processes, and connections to the combustion environments and characteristic non-combustible constituents. Based on the mechanistic understanding of how these emerging fuel streams affect materials degradation, the ultimate goal of the program is to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has been focused on studying how: (1) differing combustion environments – relative to traditional natural gas fired systems – affect both the growth rate of thermally grown oxide (TGO) layers and the stability of these oxides and of protective thermal barrier coatings (TBCs); and (2) how low levels of fuel impurities and characteristic non-combustibles interact with surface oxides, for instance through the development of molten deposits that lead to hot corrosion of protective TBC coatings. The overall program has been comprised of six inter-related themes, each comprising a research thrust over the program period, including: (i) evaluating the role of syngas and high hydrogen content (HHC) combustion environments in modifying component surface temperatures, heat transfer to the TBC coatings, and thermal gradients within these coatings; (ii) understanding the instability of TBC coatings in the syngas and high hydrogen environment with regards to decomposition, phase changes and sintering; (iii) characterizing ash deposition, molten phase development and infiltration, and associated corrosive/thermo-chemical attack mechanisms; (iv) developing a mechanics-based analysis of the driving forces for crack growth and delamination, based on molten phase infiltration, misfit upon cooling, and loss of compliance; (v) understanding changes in TGO growth mechanisms associated with these emerging combustion product streams; and (vi) identifying degradation resistant alternative materials (including new compositions or bi-layer concepts) for use in mitigating the observed degradation modes. To address the materials stability concerns, this program integrated research thrusts aimed at: (1) Conducting tests in simulated syngas and HHC environments to evaluate materials evolution and degradation mechanisms; assessing thermally grown oxide development unique to HHC environmental exposures; carrying out high-resolution imaging and microanalysis to elucidate the evolution of surface deposits (molten phase formation and infiltration); exploring thermo-chemical instabilities; assessing thermo-mechanical drivers and thermal gradient effects on degradation; and quantitatively measuring stress evolution due to enhanced sintering and thermo-chemical instabilities induced in the coating. (2) Executing experiments to study the melting and infiltration of simulated ash deposits, and identifying reaction products and evolving phases associated with molten phase corrosion mechanisms; utilizing thermal spray techniques to fabricate test coupons with controlled microstructures to study mechanisms of instability and degradation; facilitating thermal gradient testing; and developing new materials systems for laboratory testing; (3) Correlating information on the resulting combustion environments to properly assess materials exposure conditions and guide the development of lab-scale simulations of material exposures; specification of representative syngas and high-hydrogen fuels with realistic levels of impurities and contaminants, to explore differences in heat transfer, surface degradation, and deposit formation; and facilitating combustion rig testing of materials test coupons.

Mumm, Daniel↗
DOE OSTI2015

SU-E-J-271: Correlation of CT Number Change with Radiation Treatment Response for Pancreatic Cancer

Purpose: It has been reported recently that radiation can induce CT number (CTN) change during radiation therapy (RT) delivery. In the effort to explore whether CTN can be used to assess RT response, we analyze the relationship between the pathological treatment response (PTR) and the changes of CTN, MRI, and PET before and after the neoadjuvant chemoradiation (nCR) for pancreatic adenocarcinoma. Methods: The preand post-nCR CT, MRI, and PET data for a total of 8 patients with resectable, or borderline resectable pancreatic head adenocarcinoma treated with nCR were retrospectively analyzed. Radiographic characteristics were correlated to PTR data. The histograms, means and standard derivations (SD) of the CTNs in pancreatic head (CTNPH), the GTV defined by ADC (CTNGTV), and the rest of pancreatic head (CTNPH-CTNGTV) were compared. Changes before and after nCR were correlated with the corresponding changes of ADC, lean body mass normalized SUV (SUVlb), and PTR using Pearson’ s correlation coefficient test. Results: The average mean and SD in CTPH for all the patients analyzed were higher in post-nCR (53.17 ± 31.05 HU) compared to those at pre-nCR (28.09 ± 4.253 HU). The CTNGTV were generally higher than CTNPH and CTNPH-CTNGTV, though the differences were not significant. The post-nCR changes of mean CTN, ADC, and SUVlb values in pancreatic head were correlated with PTR (R=0.3273/P=0.5357, R=−0.5455/P<0.0001, and R=0.7638/P=0.0357, respectively). The mean difference in the maximum tumor dimension measured from CTN, ADC, and SUVlb as compared with pathological measurements was −2.1, −0.5, and 0.22 cm, respectively. Conclusion: The radiation-induced change of CTN in pancreas head after chemoradiation therapy of pancreatic cancer was observed, which may be related to treatment responses as assessed by biological imaging and pathology. More data are needed to determine whether the CTN can be used as a quantitative biomarker for response to neoadjuvant therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

TU-G-BRA-06: PET-Based Treatment Response Assessement for Neoadjuvent Chemoradiation for Pancreatic Adenocarcinoma

Purpose: To address the limitations of the conventional response evaluation criteria in solid tumors (RECIST), and validate PET response criteria in solid tumors (PERCIST1.0). We analyze the relationship between the pathological treatment response (PTR) and PERCIST1.0 for patients treated with neoadjuvent chemoradiation (nCR) for pancreatic adenocarcinoma. Methods: The pre- and post-nCR CT and PET data for a total of 8 patients with resectable, or borderline resectable pancreatic head adenocarcinoma treated with nCR were retrospectively analyzed. These data were compared with the PTR which were graded according to tumor cell destruction (cellularity), with Grade1, 2 or 3 (G1, G2 or G3) for good, moderate, and poor responses, respectively. RECIST-based PET (RECISTPET), and PERCIST1.0 were defined using lean body mass normalized SUV (nSUVlb). RECIST-based CT (RECISTCT) was defined by contouring the whole pancreas head (CTPH). Pre- and post-nSUVlb and SUVbw, PERCIST 1.0, were correlated with PTR using Pearson’s correlation coefficient test. Results: The average mean and SD in nSUVlb for all 8 patients analyzed were lower in post-nCR (1.35±0.34) compared to those at pre-nCR (1.38±0.20). Using PERCIST1.0, 5/8 patients showed stable metabolic disease (SMD), 2/8 partial metabolic response (PMR), and 1/8 progressive metabolic disease (PMD). Using RECISTPET 4/8 showed stable disease (STD), 4/8 partial response (PR), whereas 8/8 showed stable disease (STD) using RECISTCT. PTR were correlated with PERCIST1.0 (R=0.3780/P=0.6071). Pathological tumor size was correlated with RECISTCT (R=0.0727/P=0.8679), and RECISTPET, R=−0.3333/P=0.3798. Conclusion: Chemoradiation treatment response assessment based on metabolic tumor activities using PRECIST1.0 and RECISTPET appears to provide better agreement with pathological assessment as compared to the conventional CT-based assessment using RECISTCT. The integration of these additional radiographic metrics in assessing treatment response to nCR for pancreatic adenocarcinoma may provide a promising strategy to better select those patients most suitable for therapeutic intensification.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Lens Model Accuracy in the Expected LSST Lensed AGN Sample

Strong gravitational lensing of active galactic nuclei (AGN) enables measurements of cosmological parameters through time-delay cosmography (TDC). With data from the upcoming LSST survey, we anticipate using a sample of O(1000) lensed AGN for TDC. To prepare for this dataset and enable this measurement, we construct and analyze a realistic mock sample of 1300 systems drawn from the OM10 (Oguri & Marshall 2010) catalog of simulated lenses with AGN sources at $z<3.1$ in order to test a key aspect of the analysis pipeline, that of the lens modeling. We realize the lenses as power law elliptical mass distributions and simulate 5-year LSST i-band coadd images. From every image, we infer the lens mass model parameters using neural posterior estimation (NPE). Focusing on the key model parameters, $θ_E$ (the Einstein Radius) and $γ_{lens}$ (the projected mass density profile slope), with consistent mass-light ellipticity correlations in test and training data, we recover $θ_E$ with less than 1% bias per lens, 6.5% precision per lens and $γ_{lens}$ with less than 3% bias per lens, 8% precision per lens. We find that lens light subtraction prior to modeling is only useful when applied to data sampled from the training prior. If emulated deconvolution is applied to the data prior to modeling, precision improves across all parameters by a factor of 2. Finally, we combine the inferred lens mass models using Bayesian Hierarchical Inference to recover the global properties of the lens sample with less than 1% bias.

Venkatraman, Padmavathi [Illinois U., Urbana; KIPA↗
DOE OSTI2020

Small-Scale Drying: FY2020 Interim Report

This report documents the interim experimental status of small-scale drying tests currently being performed at Pacific Northwest National Laboratory. These small-scale drying tests are to develop the technical bases for sensors, techniques, and approaches that will be used to address the challenges faced when determining moisture content from gas samples taken at the North Anna Nuclear Generating Station for the High Burnup Demonstration Project. Specifically, the purpose of these tests is to support Sandia National Laboratories gas sample methods and analyses through a series of small-scale experiments. Key focus areas include performing tests to: • Correlate sample bottle measurements to in-cask conditions • Estimate the amount of trapped and absorbed water on cask features and surfaces that can contribute to water vapor • Assess the accuracy of the hygrometer used in the measurements under similar conditions • Identify additional methods for measuring humidity in casks easily and accurately using lessons-learned from Sandia National Laboratories, including direct gravimetric and isotopic tracer techniques. To address these topics this report outlines a series of five tests and any data collected to date that were planned for FY 2020 that include 1) humidity measurement method development, 2) gas bottle sampling tests, 3) surface drying tests on cladding, 4) small-scale drying of cladding, and 5) small-scale drying of guide-tube/dashpots. This interim report documents the experimental background, design and progress of these small-scale drying tests. Further data gathered will be summarized in the FY 2021 report.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Design, Development and Testing of Inconel Alloy IN718 Spherical Gas Bottle for Oxygen Storage

This paper describes the details of design, manufacture and testing of 200 mm diameter spherical gas bottle of Inconel 718 (IN718) with nominal wall thickness of 2.3 mm. Gas bottle was designed for the specified internal pressure loading with a thickness of 2.9 mm at the circumferential weld which was brought down to 2.3 mm at the membrane locations. Hemispherical forgings produced through closed-die hammer forging were machined and electron beam welded to produce a spherical gas bottle. Duly welded gas bottle was subjected to standard aging treatment to achieve the required tensile strength. Aged gas bottle was inspected for dimensions and other stringent quality requirements using various nondestructive testing techniques. After inspection, gas bottle was subjected to pressure test for maximum expected operating pressure and proof pressure of 25 and 37.5 MPa, respectively. Strain gauges were bonded at different locations on the gas bottle to monitor the strains during the pressure test and correlated with the predicted values. The predicted strain matched well with the experimental strain confirming the design and structural integrity.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Comprehensive Studies on Hot Compaction and Vibration-Assisted Compaction Tests of Aluminum Powder

Abstract Aluminum powder compaction was studied using both test and simulation. Cold compaction, hot compaction, and vibration-assisted (cold) compaction tests were conducted to achieve different density ratios. First, the hot compaction test (at 300 °C, compression pressure 140 MPa) improved about 6% compared with cold compaction under the same compression pressure. Second, although the relative density ratio does not obviously improve at a vibration-assisted (cold) compaction, the strength of the specimens made under vibration loading is much better than those of cold compaction. Additionally, finite element models with well-calibrated Drucker–Prager Cap (DPC) material constitutive model were built in abaqus/standard to simulate the powder compaction process. The results of the finite element model have very good correlations with test results up to the tested range, and this finite element model further predicts the loading conditions needed to achieve the higher density ratios. Two exponential equations of the predicted density ratio were obtained by combining the test data and the simulation results. A new analytical solution was developed to predict the axial pressure versus the density ratio for the powder compaction according to DPC material model. The results between the analytical solution and the simulation model have a very good match.

Engineering↗