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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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At least 1,765 records · Page 98
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Experimental and calculational investigation of laser-heated additive manufactured foams

Foam materials are starting to find application in laser-heated Hohlraums used to drive inertial confinement fusion implosions. Foams made using additive manufacturing (AM) techniques are now available and may have advantages over traditional chemical (aerogel) foams. Here, we present new experimental data on laser-heated AM foams. Samples of four different types of printed AM foams were heated using a single 527 nm laser beam at the Jupiter Laser Facility. The laser pulse was ∼180 J square pulse with an FWHM of 1.6 ns and a peak intensity of 3–4 × 1014 W/cm2. The foam densities ranged from 12 to 93 mg/cc (all supercritical for 527 nm light). We measured the backscattered light (power and spectrum), the transmitted light, side-on x-ray images, and the Ti K-shell emission that was used to infer the time-integrated temperature. The fraction of backscattered light was 6%–15% of the input laser energy. The pure carbon foam sample had less backscatter than a C8H9O3 foam of similar density, which was consistent with multi-fluid calculations that predicted less ion heating for the C8H9O3 foam. The level of backscatter and the thermal front speeds for the AM foams were similar to values measured for stochastic (aerogel) foams under similar conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Characterization and application of a high-resolution microfluidic device in atmospheric ice nucleation research and integrated science teaching

Ambient ice-nucleating particles (INPs) represent an important subset of aerosol particles that facilitate heterogeneous formation of ice crystals in the atmosphere, which can impact Earth system and energy. In this work, we developed an affordable high-resolution platform to replicate atmospheric immersion freezing through the unique capabilities of microfluidics to measure INP concentration of known ice nucleation active materials, as well as high-latitude soil samples. The new instrument produced comparable and extended freezing efficiency data for a multitude of samples over the temperature range of -5 to -35 °C as compared to an existing freezing assay within known uncertainties. Moreover, the new assay was integrated into science teaching at a primarily undergraduate and Hispanic-serving institute, contributing to fostering a deeper understanding of ice nucleation processes among college students, instilling their enthusiasm for science, and addressing the critical need for a well-informed citizenry. Student research assistants were involved in both research and pedagogical development processes. Three students from our team visited the Pacific Northwest National Laboratory to help characterize physicochemical properties of our test samples and to test modeling of atmospheric ice nucleation using a box model as well as a global climate model (E3SM) for the regional-scale conditions over the North Slope of Alaska (NSA) and Southern Great Plains (SGP). We also assessed student learning experience via hands-on training, research processes, and development of educational materials. On pre- and post-participation surveys and in exit interviews, students reported personal growth as advancements in breadth of experience, research-related skill sets, and regarding their educational and career goals. They also affirmed that the methods enacted incorporated the NASA Minority University Research and Education Program (MUREP) STEM Engagement Best Practices.

58 GEOSCIENCES↗
NASA NTRS1988

Integrated-light spectroscopy of globular clusters at the infrared Ca II lines

Integrated-light spectroscopy has been obtained for 27 globular clusters at the Ca II IR triplet. Line strengths and radial velocities have been measured from the spectra. For the well-studied clusters in the sample, the strength of the Ca II lines is very well correlated with previous metallicity estimates. Thus, the triplet is useful as a metallicity indicator in globular cluster integrated-light spectra. The greatly reduced effect of interstellar extinction at these wavelengths (compared to the blue region of the spectrum) has permitted observations of some of the most heavily reddened clusters in the Galaxy. For several such clusters, the Ca II triplet metallicities are in poor agreement with metallicity estimates from IR photometry by Malkan (1981). The strength of an interstellar band at 8621A has been used to estimate the amount of extinction towards these clusters. Using the new metallicity and radial-velocity data, the metallicity distribution, kinematics, and spatial distribution of the disk globular cluster system have been analyzed. Results very similar to those of Zinn (1985) have been found. The relation of the disk globulars to the stellar thick disk is discussed.

Armandroff, Taft E.↗
DOE OSTI2019

Renormalization group computation of likelihood functions for cosmological data sets

I show how a renormalization group (RG) method can be used to incrementally integrate the information in cosmological large-scale structure data sets (including CMB, galaxy redshift surveys, etc.). I show numerical tests for Gaussian fields, where the method allows arbitrarily close to exact computation of the likelihood function in order N time, even for problems with no symmetry, compared to N 3 for brute force linear algebra (where N is the number of data points - to be fair, methods already exist to solve the Gaussian problem in at worst N log N time, and this method will not necessarily be faster in practice). The method requires no sampling or other Monte Carlo (random) element. Nonlinearity/non-Gaussianity can be accounted for to the extent that terms generated by integrating out small scale modes can be projected onto a sufficient basis, e.g., at least in the sufficiently perturbative regime. The formulas to evaluate are straightforward and require no understanding of quantum field theory, but this paper may also serve as a pedagogical introduction to Wilsonian RG for astronomers.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Power Grid Reliability Estimation via Adaptive Importance Sampling

Electricity production currently generates approximately 25% of greenhouse gas emissions in the USA. Thus, increasing the amount of renewable energy is a key step to carbon neutrality. However, integrating a large amount of fluctuating renewable generation is a significant challenge for power grid operating and planning. Grid reliability, i.e., an ability to meet operational constraints under power fluctuations, is probably the most important of them. In this letter, we propose computationally efficient and accurate methods to estimate the probability of line overflow, i.e., reliability constraints violation, under a known distribution of renewable energy generation. To this end, we investigate an importance sampling approach, a flexible extension of Monte-Carlo methods, which adaptively changes the sampling distribution to generate more samples near the reliability boundary. The approach allows to estimate overload probability in real-time based only on a few dozens of random samples, compared to thousands required by the plain Monte-Carlo. Our study focuses on high voltage direct current power transmission grids with linear reliability constraints on power injections and line currents. Herein, we propose a novel theoretically justified physics-informed adaptive importance sampling algorithm and compare its performance to state-of-the-art methods on multiple IEEE power grid test cases.

power system faults↗
DOE OSTI2019

SRNL Report on Vendor Solicitation and Selective Ion-Electrode Testing

Effective operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will require information collected from sampling and/or monitoring to maintain environmental compliance, product quality, and operating efficiency. The U.S. Department of Energy (DOE) – Office of River Protection (ORP) recognizes the potential long-term benefit of developing real-time, in-line monitoring (RTIM) at the WTP to improve the current strategy of collecting tens of thousands of samples and analyzing them. In-line monitoring can decrease processing time associated with waiting for sample analysis, reduce workers’ exposure to radiation and chemical hazards, decrease secondary waste volumes, potentially improve product quality, and provide production support and enhance overall operational control. The Assistant Manager, WTP chartered an Integrated Technical Team (ITT), which includes personnel from the Savannah River National Laboratory (SRNL), Bechtel National, Inc., and DOE-ORP, to evaluate the capability and potential benefits of replacing routine sample collection requirements with real-time, in-line monitoring. The initial focus of the ITT is the Direct Feed Low Activity Waste (DFLAW) Program. This work scope is being performed in multiple phases. Phase 1 is Requirements and Opportunities Analysis, Phase 2 is Applications and Benefits Determination, and Phase 3 is Qualification and Demonstration. Phase 1 included 6 tasks and was completed by SRNL in 2017. The tasks in Phase 1 were: (1) determining the functional requirements for determining analytes and properties of streams, (2) determining the technical basis for process control, (3) determining the sampling points within the Low Activity Waste (LAW) facility and Effluent Management Facility (EMF), (4) data quality and management, (5) process control challenges, and (6) preparing a Preliminary Analysis Plan. DOE-ORP was briefed on the findings from the Phase 1 tasks and requested that Phase 2 work focus on establishing a basis for a materials balance approach that minimized process sampling. The Phase 2 work scope contains tasks to evaluate a materials balance only approach as well as continuing scoping evaluations for instruments that could be used for RTIM. The Phase 2 work scope was completed by both SRNL and Pacific Northwest National Laboratory (PNNL). The tasks performed in Phase 2 were: 1. Overall program administration and technical oversight 2. Evaluation of a Material Balance Approach, a. Evaluation of uncertainty of this approach compared to uncertainty of current methods b. Evaluation of automating the material balance within the framework of existing control software, c. Development of the methodology to obtain and evaluate data during cold commissioning to support a material balance approach, and d. Development of a framework to utilize during presentation of the revised approach to stakeholders and regulators. 3. Screening Evaluations of Instruments to Supplement the Material Balance Approach, a. AP-105 melter condensate evaluations, and b. Screening testing with simulants. 4. Evaluation of the current DFLAW feed qualification program to identify analytes that could be eliminated, a. Inorganic analytes, b. Radionuclides, and c. Organic analytes. This report describes the results of Task 3b, Screening testing with simulants. The Savannah River National Laboratory requested demonstrations of commercially available analytical instruments by the vendors or laboratory demonstration. The techniques tested included: Raman spectroscopy, Infrared spectroscopy (IR), laser induced breakdown spectroscopy (LIBS), X-Ray Fluorescence Spectroscopy (XRF), and ion-selective electrochemical probes. Additionally, the instrumentation would need to be durable enough to withstand the environment of the plant, preferably with little to no maintenance. The insertion point of the instrument would be dependent upon the instrumentation.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Total Recoverable Aluminum: Not Totally Relevant for Water Quality Standards

Abstract A large water quality data set, representing more than 100 surface-water locations sampled from 2007 to 2017 in the Los Alamos area of New Mexico, USA's Pajarito Plateau, was assembled to evaluate Al concentrations in unfiltered and filtered samples. Aluminum concentrations often exceeded United States Environmental Protection Agency (USEPA) and New Mexico ambient water quality criteria (AWQC), regardless of filter size and sample location. However, AWQC are based on laboratory toxicity studies using soluble Al salts and do not reflect natural conditions in Pajarito Plateau surface waters. The plateau is predominately covered by glassy and recrystallized volcanic ashes (e.g., Bandelier Tuff) containing colloidal to sand-sized aluminosilicates. Samples from natural background drainages and areas downstream of developed regions exhibited similar Al concentrations, suggesting that AWQC exceedances are caused by naturally elevated Al concentrations. Solubility calculations indicated that most samples were oversaturated with respect to amorphous Al(OH)3(s). Therefore, AWQC exceedances are likely artifacts of the “total recoverable” sample preparation, which includes acidification and partial digestion, thereby liberating nonbioavailable Al from aluminosilicates. Accordingly, Al concentrations were strongly associated with suspended sediment concentrations (SSCs), implying that aluminosilicates in suspended sediment contributed to AWQC exceedances and Al oversaturation. Solid-phase particle characterization, using X-ray diffraction (XRD) and scanning electron microscopy with electron dispersive spectroscopy (SEM/EDS) did not identify potentially bioavailable amorphous Al(OH)3(s) in any sample tested. Thus, current sample collection and analysis protocols should not be used to evaluate attainment of Al AWQC on the Pajarito Plateau or locations where aluminosilicates are substantial contributors to total recoverable Al. A sample preparation method (e.g., pH 4 extraction) capable of differentiating nonbioavailable and bioavailable forms of Al is recommended. Otherwise, current New Mexico and USEPA sample preparation approaches will continue to generate artifactual AWQC exceedances in surface waters that contain aluminosilicates. Integr Environ Assess Manag 2019;00:1–14. © 2019 SETAC

Ryan, Adam C.↗
DOE OSTI2018

Measurement of branching fractions of charmless four-body Λ o b and Ξ o b decays

A search for charmless four-body decays of Λ o b and Ξ o b baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fb –1 . Six decay modes are observed, among which Λ o b → pK – π + π – , Λ o b → pK – K + K – , Ξ o b → pK – π + π – and Ξ o b → pK – π + K – are established for the first time. Their branching fractions (including the ratio of hadronisation fractions in the case of the Ξ o b baryon) are determined relative to the Λ o b → Λ c + π – decay.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Measurement of differential t-channel single top (anti)quark production cross-sections at 13 TeV with the ATLAS detector

The production of single top quarks and top antiquarks via the t-channel exchange of a virtual W boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The full Run 2 data sample recorded with the ATLAS detector in the years 2015–2018 is used, corresponding to an integrated luminosity of 140 fb−1. The absolute and normalised production cross-sections are measured differentially as a function of the transverse momentum and absolute rapidity of the top quark and top antiquark. In addition, the ratio of top quark to top antiquark production cross-sections is measured. The measured distributions are compared with next-to-leading-order quantum chromodynamics predictions obtained with different combinations of matrix-element generators, parton-shower programs and proton parton distribution functions, as well as to next-to-next-to-leading-order calculations. Overall, good agreement is observed between the measurements and the theoretical predictions. For most measured distributions, the sensitivity to differences between the predictions is limited by the systematic uncertainties in the measurement. The measured differential distributions are also interpreted in an effective field theory approach to constrain the Wilson-Coefficient CQq3,1$$ {C}_{Qq}^{3,1} $$ associated with a four-quark operator. The interpretation accounts for the effect of the selection efficiency, which is altered significantly by non-zero contributions from CQq3,1$$ {C}_{Qq}^{3,1} $$.

Aad, G↗
DOE OSTI2016

Phenomenological MSSM interpretation of CMS searches in pp collisions at sqrt(s) = 7 and 8 TeV

Searches for new physics by the CMS collaboration are interpreted in the framework of the phenomenological minimal supersymmetric standard model (pMSSM). The data samples used in this study were collected at $ \sqrt{s}=7 $ and 8 TeV and have integrated luminosities of 5.0 fb$^{−1}$ and 19.5 fb$^{−1}$, respectively. A global Bayesian analysis is performed, incorporating results from a broad range of CMS supersymmetry searches, as well as constraints from other experiments. Because the pMSSM incorporates several well-motivated assumptions that reduce the 120 parameters of the MSSM to just 19 parameters defined at the electroweak scale, it is possible to assess the results of the study in a relatively straightforward way. Approximately half of the model points in a potentially accessible subspace of the pMSSM are excluded, including all pMSSM model points with a gluino mass below 500 GeV, as well as models with a squark mass less than 300 GeV. Models with chargino and neutralino masses below 200 GeV are disfavored, but no mass range of model points can be ruled out based on the analyses considered. The nonexcluded regions in the pMSSM parameter space are characterized in terms of physical processes and key observables, and implications for future searches are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Natural fluorapatite as a raw material for Portland clinker

The present work focuses on the mineralogy and the reactivity of clinkers made from the integration of natural fluorapatite in the raw meals with percentages ranging from 0 up to15%. The samples were characterized by infrared spectrometry, X-ray diffraction and microscopy techniques. The distribution of phosphorous and fluorine into clinkers minerals was determined by MEB/EDS mapping. The mineralogical composition was determined by XRD/Rietveld and the samples reactivity followed by isothermal microcalorimetry. It has been found that fluorine stabilizes C{sub 3}S and β-C{sub 2}S which still are found with high levels of P{sub 2}O{sub 5}. Cements obtained from up to 8% natural fluorapatite incorporation still present acceptable properties. Natural fluorapatite could have an important potential as decarbonised source of CaO contributing to decrease the CO{sub 2} emission in cement industry.

36 MATERIALS SCIENCE↗
DOE OSTI2022

A portable fiber optic sensor for the luminescent sensing of cobalt ions using carbon dots

Cobalt is critical to energy-relevant technologies, and demand for cobalt will increase significantly with growing global adoption of renewables. However, supply chain stability is threatened by economic and geopolitical factors, incentivizing domestic cobalt production from alternative resources such as coal, coal utilization byproducts (e.g., ash, acid mine drainage) and electronic waste. Rapid, inexpensive, and portable characterization techniques are needed to reduce production costs associated with cobalt prospecting and process monitoring. Here, in this research, we develop a compact, portable fiber optic luminescent probe for cobalt using phosphorus and nitrogen co-doped carbon dots as the sensing material. The carbon dot emission overlaps well with the cobalt absorption band at ~510 nm, leading to a selective decrease in emission as a function of cobalt concentration. The system responds nearly instantly to the presence of cobalt, with detection limits of 0.7 and 3.5 ppm in water and pH 1.68 buffer, respectively, providing comparable performance to a commercial spectrometer at a significantly lower cost. Moreover, the sensor is selective for cobalt in the presence of 13 of the most common metal ions encountered in coal utilization byproducts and is responsive to cobalt when spiked into an acid mine drainage leachate sample, highlighting the sensor's potential for real-world deployment in challenging matrices. In addition, integrating the carbon dots with a filter paper substrate produced ‘test strip’ sensors that exhibited a selective and sensitive visual response to cobalt using a handheld UV lamp. Taken together, the sensing system represents a significant step forward in the development of low-cost practical sensors for high-value metals in complex streams.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

STAR CLUSTER PROPERTIES IN TWO LEGUS GALAXIES COMPUTED WITH STOCHASTIC STELLAR POPULATION SYNTHESIS MODELS

We investigate a novel Bayesian analysis method, based on the Stochastically Lighting Up Galaxies (slug) code, to derive the masses, ages, and extinctions of star clusters from integrated light photometry. Unlike many analysis methods, slug correctly accounts for incomplete initial mass function (IMF) sampling, and returns full posterior probability distributions rather than simply probability maxima. We apply our technique to 621 visually confirmed clusters in two nearby galaxies, NGC 628 and NGC 7793, that are part of the Legacy Extragalactic UV Survey (LEGUS). LEGUS provides Hubble Space Telescope photometry in the NUV, U, B, V, and I bands. We analyze the sensitivity of the derived cluster properties to choices of prior probability distribution, evolutionary tracks, IMF, metallicity, treatment of nebular emission, and extinction curve. We find that slug's results for individual clusters are insensitive to most of these choices, but that the posterior probability distributions we derive are often quite broad, and sometimes multi-peaked and quite sensitive to the choice of priors. In contrast, the properties of the cluster population as a whole are relatively robust against all of these choices. We also compare our results from slug to those derived with a conventional non-stochastic fitting code, Yggdrasil. We show that slug's stochastic models are generally a better fit to the observations than the deterministic ones used by Yggdrasil. However, the overall properties of the cluster populations recovered by both codes are qualitatively similar.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Model-independent measurement of 𝐷 0 −$\overline{D}$ 0 mixing parameters in 𝐷 0 → 𝐾$^{0}_{𝑆}$⁢𝜋 + ⁢𝜋 − decays at Belle and Belle II

We perform a model-independent measurement of the 𝐷 0 −$\overline{D}$ 0 mixing parameters using samples of 𝑒 + ⁢𝑒 − -collision data collected by the Belle and Belle II experiments that have integrated luminosities of 951 fb −1 and 408 fb −1 , respectively. Approximately 2.05 × 10 6 neutral 𝐷 mesons are reconstructed in the 𝐷 0 → 𝐾$^{0}_{S}$⁢𝜋 + ⁢𝜋 − channel, with the neutral 𝐷 flavor tagged by the charge of the pion in the 𝐷* + → 𝐷 0⁢ 𝜋 + decay. Assuming charge-parity symmetry, the mixing parameters are measured to be 𝑥 = (4.0 ±1.7 ±0.4) × 10 −3 and 𝑦 = (2.9 ±1.4 ±0.3) × 10 −3 , where the first uncertainties are statistical and the second systematic. The results are consistent with previous determinations.

Charmed mesons↗
DOE OSTI2016

Evidence for Exotic Hadron Contributions to Λ b 0 → J / ψ p π – Decays

A full amplitude analysis of Λ 0 b →J/ψpπ – decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb –1 . A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations N→pπ – , either the P c (4380) + and P c (4450) + →J/ψp states, previously observed in Λ 0 b →J/ψpK – decays, or the Z c (4200) – →J/ψπ – state, previously reported in B 0 →J/ψK + π – decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the P c (4380) + and P c (4450) + production rates expected from their previous observation taking account of Cabibbo suppression.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Search for Time-Dependent C P Violation in D 0 → π + π − π 0 Decays

A measurement of time-dependent C P violation in D 0 → π + π − π 0 decays using a p p collision data sample collected by the LHCb experiment in 2012 and from 2015 to 2018, corresponding to an integrated luminosity of 7.7 fb − 1 , is presented. The initial flavor of each D 0 candidate is determined from the charge of the pion produced in the D * ( 2010 ) + → D 0 π + decay. The decay D 0 → K − π + π 0 is used as a control channel to validate the measurement procedure. The gradient of the time-dependent C P asymmetry Δ Y in D 0 → π + π − π 0 decays is measured to be Δ Y = ( − 1.3 ± 6.3 ± 2.4 ) × 10 − 4 , where the first uncertainty is statistical and the second is systematic, which is compatible with C P conservation. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2026

Magnetic Measurements of Fermilab Rapid-Cycling Booster Gradient Magnets

Fermilab is upgrading its Booster synchrotron to increase ramp rate and intensity. This is part of the Proton Improvement Plan (PIP-II) that will allow the Main Injector to achieve proton beam power of 1.2 MW within the next few years. This upgrade includes running the 55-year-old Booster magnets at 20 Hz instead of the usual 15 Hz, and construction of some shorter and wider aperture versions of these combined-function gradient magnets. Magnetic measurements were performed to characterize the present 15 Hz AC performance, and then again with 20 Hz ramp cycle to ensure performance and compatibility in this new operating regime. A 3 m-long curved flat-coil was developed for these measurements using Printed Circuit Board (PCB) technology. The probe also has a separate 0.5 m-long body-field probe, allowing integral, body, and end fields to be measured across 100 mm of the magnet aperture. The sampling rate for these measurements during the AC cycle was 200 kHz, and field resolution was better than 0.01%. Details of the probe, measurements, and results are presented.

DiMarco, J. [Fermilab] (ORCID:0000000228400036)↗