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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 OSTI2023

Impact of Electrolyte Composition on Bulk Electrolysis of Furfural over Platinum Electrodes

Partial oxidation of furanic biomass derivatives such as furfural is of interest for the sustainable production of chemicals including furoic acid, maleic acid, and 2,5-furandicarboxylic acid (FDCA). The oxidative bulk electrolysis of furfural is here investigated on platinum electrodes in acidic media. The effects of potential, concentration, pH, and supporting anion are studied, and selectivity trends are coupled with attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) to illuminate adsorbate structures that influence the catalysis. Increasing potential is found to shift selectivity from primarily C 5 products to C 4 products, coincident with oxidation of the Pt surface. Selectivity changes are also observed moving from pH 1 to pH 4, with an increase in C 5 products at higher pH. Furthermore, changing from the weakly adsorbing perchlorate anion to the specifically-adsorbing phosphate anion results in a number of changes that manifest differently depending on potential and pH. Selectivity to furoic acid is found to be highest above the pKa of phosphoric acid due to the strongly adsorbed phosphate ions suppressing flat-lying configurations of furfural that lead to C−C cleavage. These results point toward opportunities to use electrolyte engineering to tune selectivity and optimize surface conditions to disfavor binding of inhibitory products.

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

Multi‐dimensional lock‐free arrays for multithreaded mode‐directed tabling in Prolog

Summary This work proposes a new design for the supporting data structures used to implement multithreaded tabling in Prolog systems. Tabling is an implementation technique that improves the expressiveness of traditional Prolog systems in dealing with recursion and redundant computations. Mode‐directed tabling is an extension to the tabling technique that supports the definition of alternative criteria for specifying how answers are aggregated, thus being very suitable for problems where the goal is to dynamically calculate optimal or selective answers. In this work, we leverage the intrinsic potential that mode‐directed tabling has to express dynamic programming problems by creating a new design that improves the representation of multi‐dimensional arrays in the context of multithreaded tabling. To do so, we introduce a new mode for indexing arguments in mode‐directed tabled evaluations, named dim , where each dim argument features a uni‐dimensional lock‐free array. Experimental results using well‐known dynamic programming problems on a 32‐core machine show that the new design introduces less overheads and clearly improves the execution time for sequential and multithreaded tabled evaluations.

Areias, Miguel↗
DOE OSTI2019

Search for heavy resonances decaying into two Higgs bosons or into a Higgs boson and a W or Z boson in proton-proton collisions at 13 TeV

A search is presented for massive narrow resonances decaying either into two Higgs bosons, or into a Higgs boson and a W or Z boson. The decay channels considered are $ \mathrm{H}\mathrm{H}\to \mathrm{b}\overline{\mathrm{b}}{\tau}^{+}{\tau}^{-} $ and $ \mathrm{V}\mathrm{H}\to \mathrm{q}\overline{\mathrm{q}}{\tau}^{+}{\tau}^{-} $ , where H denotes the Higgs boson, and V denotes the W or Z boson. This analysis is based on a data sample of proton-proton collisions collected at a center-of-mass energy of 13 TeV by the CMS Collaboration, corresponding to an integrated luminosity of 35.9 fb$^{−1}$. For the TeV-scale mass resonances considered, substructure techniques provide ways to differentiate among the hadronization products from vector boson decays to quarks, Higgs boson decays to bottom quarks, and quark- or gluon-induced jets. Reconstruction techniques are used that have been specifically optimized to select events in which the tau lepton pair is highly boosted. The observed data are consistent with standard model expectations and upper limits are set at 95% confidence level on the product of cross section and branching fraction for resonance masses between 0.9 and 4.0 TeV. Exclusion limits are set in the context of bulk radion and graviton models:spin-0 radion resonances are excluded below a mass of 2.7 TeV at 95% confidence level. In the spin-1 heavy vector triplet framework, mass-degenerate W′ and Z′ resonances with dominant couplings to the standard model gauge bosons are excluded below a mass of 2.8 TeV at 95% confidence level. These are the first limits for massive resonances at the TeV scale with these decay channels at $ \sqrt{s}=13 $ TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Sensitivity of the NEXT experiment to Xe-124 double electron capture

Double electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture (2$\nu$EC EC) has been predicted for a number of isotopes, but only observed in 78 Kr, 130 Ba and, recently, 124 Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, 0$\nu$EC EC. Here we report on the current sensitivity of the NEXT-White detector to 124 Xe 2$\nu$EC EC and on the extrapolation to NEXT-100. Using simulated data for the 2$\nu$EC EC signal and real data from NEXT-White operated with 124 Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of 124 Xe and for a 5-year run, a sensitivity to the 2$\nu$EC EC half-life of 6 × 10 22 y (at 90% confidence level) or better can be reached.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Measurement of the inclusive WZ production cross section in pp collisions at $\sqrt{\textrm{s}}$ = 13.6 TeV

The inclusive WZ production cross section is measured in proton-proton collisions at a centre-of-mass energy of 13.6 TeV, using data collected during 2022 with the CMS detector, corresponding to an integrated luminosity of 34.7 fb −1 . The measurement uses multileptonic final states and a simultaneous likelihood fit to the number of events in four different lepton flavour categories: eee, ee μ , μμ e, and μμμ . The selection is optimized to minimize the number of background events, and relies on an efficient prompt lepton discrimination strategy. The WZ production cross section is measured in a phase space defined within a 30 GeV window around the Z boson mass, as σ total (pp → WZ) = 55.2 ± 1.2 (stat) ± 1.2 (syst) ± 0.8 (lumi) ± 0.3 (theo) pb. In addition, the cross section is measured in a fiducial phase space closer to the detector-level requirements. All the measurements presented in this paper are in agreement with standard model predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Search for $ \mathrm{t}\overline{\mathrm{t}} $ resonances in highly boosted lepton+jets and fully hadronic final states in proton-proton collisions at $ \sqrt{s}=13 $ TeV

A search for the production of heavy resonances decaying into top quark-antiquark pairs is presented. The analysis is performed in the lepton+jets and fully hadronic channels using data collected in proton-proton collisions at $ \sqrt{s}=13 $ TeV using the CMS detector at the LHC, corresponding to an integrated luminosity of 2.6 fb$^{−1}$. The selection is optimized for massive resonances, where the top quarks have large Lorentz boosts. No evidence for resonant $ \mathrm{t}\overline{\mathrm{t}} $ production is found in the data, and upper limits on the production cross section of heavy resonances are set. The exclusion limits for resonances with masses above 2 TeV are significantly improved compared to those of previous analyses at $ \sqrt{s}=8 $ TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Technical and Imaging Outcomes from the UK Registry of Prostate Artery Embolization (UK-ROPE) Study: Focusing on Predictors of Clinical Success

Introduction: The UK Registry of Prostate Artery Embolization (UK-ROPE) was a prospective, multicentre study comparing PAE against surgical therapies for symptomatic benign prostatic hyperplasia (BPH). A wealth of data was collected supplementary to the main study outcomes which provide a snapshot of UK PAE practice. We aimed to interpret these data in the hope of providing insight into factors which affect clinical outcome and radiation dose. Methods: 216 patients (mean age 66, mean IPSS 21.3) undergoing PAE at 20 British centres from July 2014 to January 2016 were prospectively followed up to 12 months with retrospective analysis of the data. Technical outcome was evaluated based on procedural and fluoroscopy times, skin dose and dose area product (DAP). Clinical outcome was evaluated through collection of Qmax, IPSS reduction and prostate volume reduction. Multiple analysis of variance (MANOVA) was used to assess the significance of various patients and procedural factors on clinical outcome and patient dose. Results: Significant predictors of technical outcome which affected patient skin dose included severity of CTA-detected atheroma (p < 0.001), the practitioner (p < 0.001) and use of protective coil embolization (p = 0.019). Predictors of clinical outcome included initial prostate size (dichotomized into groups > 80 ml and = <80 ml, d = 1, p = 0.0138), embolic agent (spherical particles < 300 nm performed best, p = 0.01) and number of arteries embolized (IPSS reduction of 32.9% in unilateral PAE versus 54.4% for bilateral PAE, p = 0.026). Conclusion: We have identified several important factors which are associated with improved clinical outcome and increased patient dose which we hope will facilitate optimal patient selection and encourage improved embolization technique.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Antibacterial and Structural Properties and Printability of Starch/Clay/Polyethylene Composite Films

A composite of thermoplastic starch (TPS), low-density polyethylene (LDPE) and citric acid-modified montmorillonite (CMMT) was prepared in a twin screw extruder for packaging film application. Starch was first converted to the thermoplastic state by using sorbitol and water. Composite films were produced on a chill roll system and then were modified for printability by grafting of acrylonitrile onto the starch backbone. Antimicrobial property and printability of the films were studied from which the sample with the highest antimicrobial property and the best printability was selected. This optimal sample was then characterized by Fourier transform infrared, thermal gravimetric analysis, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. The composite film showed a matrix/dispersed morphology in which LDPE formed a continuous phase and TPS/CMMT nanocomposite particles appeared as dispersed phase. Biodegradability, water absorption, oxygen permeability, tensile strength and transparency of optimal film were also studied. The results indicated very good properties of the produced composite film for packaging application. Graphical Abstract: .

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Effect Laws of Different Factors on Levitation Characteristics of High-T{sub c} Superconducting Maglev System with Numerical Solutions

The interaction between the high-temperature superconducting (HTS) bulk and permanent magnet guideway (PMG) has been a topic among the existing HTS magnetic levitation systems. Up to now, the theories about the electromagnetic and force characteristics have been relatively consummated. Here, using the finite element model by COMSOL Multiphysics 5.3a, we investigated the impact of the intrinsic and external factors on the levitation characteristics of HTS maglev systems, the application laws are concluded. Factors including the critical current density and geometric dimensions of the bulk superconductor, as well as the moving velocity, are discussed. The effects of the multiple back and forth movements are also analyzed. By comparing calculation results of the distributions of the induced current and the levitation force of the bulk superconductor, we can clearly confirm the effect laws of various factors on the electromagnetic characteristics and levitation force. These observations support the physical parameters that are difficult to be tested by experiments. And they also have a significant contribution to the experimental condition selections and optimization of the high-temperature superconducting magnetic levitation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Cerebral quantification of N-acetyl aspartate, aspartate, and glutamate levels in local structures of the human brain using J-editing of {sup 1}H magnetic resonance spectra in vivo

A procedure was developed for the first time for simultaneous in vivo quantification of local aspartate and glutamate concentrations in the human brain using {sup 1}H magnetic resonance spectroscopy ({sup 1}H MRS) and spectral J-editing. The MEGA-PRESS pulse sequence was modified to observe β-CH{sub 2} nonequivalent proton resonances of aspartate (δ 2.65 and 2.80) and glutamate (δ 2.04 and 2.12) overlapped by signals of other metabolites. The frequencies, frequency selective pulse durations, and optimal echo times were selected by simulation and experimentally (for phantoms and in the brain in vivo).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2–7 m, while providing data at sub-mm to mm scales. We report on SuperCam’s science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.

47 OTHER INSTRUMENTATION↗
DOE OSTI2026

Geothermal-integrated thermally anisotropic building envelope for energy and peak-demand reduction

Buildings consume large amounts of energy for heating and cooling, while peak electricity demand places significant stress on the power grid. This paper presents a reduced-order co-simulation framework and load-oriented supervisory control strategy for a geothermal-integrated thermally anisotropic building envelope with a ground loop (TABE+GL). In TABE+GL, a hydronic loop embedded in the building envelope is directly coupled with a geothermal ground loop, allowing for bidirectional heat exchange between the envelope, the ground, and the indoor environment. A hybrid co-simulation framework was established by coupling a reduced-order resistor–capacitor (RC) thermal network model with EnergyPlus augmented with GHEDesigner modules. The RC model generated feasible heat flux options under three operating modes, and EnergyPlus predicted sensible loads, energy use, and pump energy demand. At each simulation step, a supervisory control algorithm selected the optimal loop configuration and duty factor that maximizes useful TABE geothermal utilization without exceeding the predicted sensible load, thereby avoiding overheating or cooling. Case studies were conducted for Los Angeles, California, Charleston, South Carolina, and Denver, Colorado. Results showed that the proposed framework reduced HVAC electricity consumption by 43%–67%, natural gas use for space heating by 11%–38%, and peak electricity demand by 43%–88%. These results highlight the potential of combining reduced-order envelope modeling, direct geothermal coupling, and load-oriented supervisory control to improve whole building energy performance and reduce peak demand across diverse weather conditions.

Howard, Daniel [Southern Adventist University]↗
DOE OSTI2018

Vertebroplasty in Elderly Patients: A Clinical Effectiveness Analysis

Purpose of Review: Minimally invasive vertebral augmentation procedures (VAP) have been first introduced to provide pain relief in patients with osteoporotic vertebral fractures (VF). However, in the last decade scientific literature revealed to be quite controversial about their efficacy. The aim of this review was to analyze clinical evidences from current literature, supported by our own experience. Recent Findings: Compared to conservative therapies, VAP represent an effective treatment for recent VF and, in elderly patients, reduce mortality and morbidity. Advances in technology have widened the fields of application towards other spine pathologies typical of elderly, such as primary and metastatic tumors. Summary: In patients with severe pain for recent or un-healed vertebral fracture, VAP are clinically more effective than conservative treatment. Accurate pain assessment and pre-procedural Magnetic Resonance Imaging are highly recommended to obtain optimal patient selection and best treatment results.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

TOPSIS with similarity measure for MADM applied to network selection

In this article, a new method is introduced to handle fuzzy multi-attribute decision-making problems. The method preserves fuzziness in the preference technique to avoid the drawbacks of defuzzification. The study modifies the technique of order preference by similarity to an ideal solution (TOPSIS) for interval-valued fuzzy numbers. The traditional TOPSIS uses the relative degree of closeness to rank the alternatives. Instead, a similarity measure based on map distance is used for preference. The degree of similarity between each attribute of an alternative and the ideal solution is computed, and a similarity matrix is formed. Then, the total degree of similarity for all the attributes of an alternative is used for ranking. The alternative corresponding to the one norm of the similarity matrix is the best alternative. Thus, the comparison is done on a fuzzy basis to avoid the loss of information due to converting the elements of the weighted normalized decision matrix to crisp values by defuzzification. An illustrative example is given to demonstrate the approach. A practical example in network selection to optimize vertical hand offs is solved where both user preferences and network parameters are treated as interval-valued fuzzy numbers.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

An efficient Bayesian data-worth analysis using a multilevel Monte Carlo method

Improving the understanding of subsurface systems and thus reducing prediction uncertainty requires collection of data. As the collection of subsurface data is costly, it is important that the data collection scheme is cost-effective. Design of a cost-effective data collection scheme, i.e., data-worth analysis, requires quantifying model parameter, prediction, and both current and potential data uncertainties. Assessment of these uncertainties in large-scale stochastic subsurface hydrological model simulations using standard Monte Carlo (MC) sampling or surrogate modeling is extremely computationally intensive, sometimes even infeasible. In this paper, we propose an efficient Bayesian data-worth analysis using a multilevel Monte Carlo (MLMC) method. Compared to the standard MC that requires a significantly large number of high-fidelity model executions to achieve a prescribed accuracy in estimating expectations, the MLMC can substantially reduce computational costs using multifidelity approximations. Since the Bayesian data-worth analysis involves a great deal of expectation estimation, the cost saving of the MLMC in the assessment can be outstanding. While the proposed MLMC-based data-worth analysis is broadly applicable, we use it for a highly heterogeneous two-phase subsurface flow simulation to select an optimal candidate data set that gives the largest uncertainty reduction in predicting mass flow rates at four production wells. Finally, the choices made by the MLMC estimation are validated by the actual measurements of the potential data, and consistent with the standard MC estimation. But compared to the standard MC, the MLMC greatly reduces the computational costs.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Carbon fiber synthesis from pitch: Insights from ReaxFF based molecular dynamics simulations

Despite the potential to lowering fabrication costs of pitch-based carbon fiber (CF) compared to polyacrylonitrile-based CF, large scale utilization is currently limited by the complexity in manufacturing. This is mainly due to the lack of consistency between the pitch structure/chemistry and CF properties under different processing conditions. Here, we employed full atomistic simulations based on reactive force fields to investigate the conversion of pitch precursors to CFs. Additionally, it was found that at the carbonization stage, the consumption rates of precursors, gas formations, and solid yields (carbonized CFs) are all dependent on the composition and arrangement of molecular moieties in the precursor. Specifically, precursors with sp 3 carbons in the cata-condensed core area have limited decomposition pathways (i.e., limited reaction sites), which leads to the formation of carbonized CFs with similar compositions. Furthermore, carbonized CFs possess distinct structural characteristics, and finally lead to the formation of CFs with different moduli. By analyzing CF crystallinity and elemental composition, general rationales are proposed for the selection of optimal precursors and processing conditions, and thus shed lights on parameter screening during industrial CF synthesis. For instance, inclusion of sp 3 carbons in cata- condensed rings can be preferred over the presence of sp 3 carbons on side chains.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2026

Demonstration of a 228 Ra/ 228 Ac isotope generator

An isotope generator to produce 228 Ac from 228 Ra was developed using a cation exchange resin column eluted with an acetate-diethylenetriaminpentaacetic acid buffer. Here, the elution behavior of 228 Ac on the column was studied with solutions of various pHs to select the optimal conditions. Two identical isotope generators were eluted for 47 days with over 100 mL of eluant with no detectable 228 Ra breakthrough and high 228 Ac yields (∼95%). The separation requires only biocompatible reagents and is performed at pH 4.6, conditions suitable for radiopharmaceutical studies of Ac.

and nuclear chemistry↗
DOE OSTI2021

Monitoring agroecosystem productivity and phenology at a national scale: A metric assessment framework

Effective measurement of seasonal variations in the timing and amount of production is critical to managing spatially heterogeneous agroecosystems in a changing climate. Although numerous technologies for such measurements are available, their relationships to one another at a continental extent are unknown. Using data collected from across the Long-Term Agroecosystem Research (LTAR) network and other networks, we investigated correlations among key metrics representing primary production, phenology, and carbon fluxes in croplands, grazing lands, and crop-grazing integrated systems across the continental U.S. Metrics we examined included gross primary productivity (GPP) estimated from eddy covariance (EC) towers and modelled from the Landsat satellite, Landsat NDVI, and vegetation greenness (Green Chromatic Coordinate, GCC) from tower-mounted PhenoCams for 2017 and 2018. Overall, our analysis compared production dynamics estimated from three independent ground and remote platforms using data for 34 agricultural sites constituting 51 site-years of co-located time series. Pairwise sensor comparisons across all four metrics revealed stronger correlation and lower root mean square error (RMSE) between end of season (EOS) dates (Pearson R ranged from 0.6 to 0.7 and RMSE from 32.5 to 67.8) than start of season (SOS) dates (0.46 to 0.69 and 40.4 to 66.2). Overall, moderate to high correlations between SOS and EOS metrics complemented one another except at some lower productivity grazing land sites where estimating SOS can be challenging. Growing season length estimates derived from 16-day satellite GPP (179.1 days) were significantly longer than those from PhenoCam G CC (70.4 days, p adj < 0.0001) and EC GPP (79.6 days, p adj < 0.0001). Landscape heterogeneity did not explain differences in SOS and EOS estimates. Annual integrated estimates of productivity from EC GPP and PhenoCam G CC diverged from those estimated by Landsat GPP and NDVI at sites where annual production exceeds 1000 gC/m –2 yr –1 . Based on our results, we developed a “metric assessment framework” that articulates where and how metrics from satellite, eddy covariance and PhenoCams complement, diverge from, or are redundant with one another. The framework was designed to optimize instrumentation selection for monitoring, modeling, and forecasting ecosystem functioning with the ultimate goal of informing decision-making by land managers, policy-makers, and industry leaders working at multiple scales.

54 ENVIRONMENTAL SCIENCES↗